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Nov 11, 2010, 02:30 PM
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Nine Eagles Solo Pro I/II/V1/V2/270/Bravo SX FAQ (FAQ part in the first 3 postings!)


After this little Fixed Pitch heli (also known as the NE260A) got more popular, and information was spread around among various topics, I decided to start a FAQ. As the Bravo SX (NE320A), an updated Solo Pro with scale fuselage, still uses the same head setup, most tips do apply on that one as well.

Thread Rules: The general purpose of this thread is to discuss technical matters regarding this heli and keep it as informative as possible. Please be polite and respectfull to each other. More general remarks like "I just bought this heli and it is great!" or "I just received my extra batteries, now I can fly a lot more!" are not what this thread is for! Please use the general Solo Pro thread for this, using the link provided a few lines below. Same applies to sales and deals. Please post deals here:

Please observe this and we can keep this thread as useful as can be. From time to time I will remove postings that break these rules. Finally, I hope you will find the answers you were looking for in this thread. Enjoy!

Update: Nine Eagles have released other helis that are also called "Solo Pro" but with a suffix, like "328" or so, behind the "SP" part. These helis are mostly very different to the heli range this topic was created for. User "frank fjs" has created a topic, with links to the respective topics for many other "Solo Pro" heli:

In 2012 the Solo Pro 270 appeared. It uses a different head, and there are more differences with the NE260A. Here is the topic where this heli can be discussed in general:

For some 270 FAQ info, please check the 3rd posting in this thread.

For completeness, here's the link to the regular Solo Pro (260) thread, the first heli in this range. It may also be interesting to read about it's history.

And the link to the general Bravo SX thread:

I heartily recommend checking that as well.

Finally, although upgrades are also discussed in the second posting in this thread, here's the link to the thread where (Xtreme) upgrades are discussed:

Disclaimer: I do not work for Nine Eagles or sell helicopters. Most of the information listed here is from personal experience, or found on this or other forums. So I don't claim to be the inventor of all the tips listed here. Do you see some reference to a discovery you made, please see it as a compliment your discovery is listed here. Usage of this information is purely at your own risk. This FAQ is a Work in Progress, so things could be missing.

Finally, a warning!: It seems standard heli batteries for the Solo Pro are not fully up to the job. This is also discussed under "Power Options" with a graph to show it's lack of performance. The voltage drop can sometimes mess with the programming of the board, causing servo lockups as most common problem. As a precaution, it would be wise to get better batteries, and not to push flight times too far. This does not apply to the stock Bravo SX batteries, these are of better quality. Also check the metal battery contacts in the heli, bad contacts can also cause glitches.

First Impressions:

Q 1: I have a Revell Proto Max, Soar, Robbe Nano Arrow, Merlin Tracer 90... and it looks just like the Solo Pro. Is my heli an illegal copy?

A:There is nothing wrong. Nine Eagles products are often rebranded. Most of the times this means you only get a different canopy and tailfin, but the heli is the same. Parts from the Solo Pro should and will fit. Or if you have a Solo Pro, parts from Revell etc will also fit. You might get better warranty conditions when getting a rebranded Solo Pro, although a good shop will replace faulty items no matter what the name on the box. So whatever brand you choose, you are getting the same heli.

Q 2: The leds are flashing when I insert the battery, and also when I throttle up. Is something wrong?

A: The leds on the receiver board serve as indicators. When inserting the battery, the blue led will become solid, then start flashing, and finally become solid again, indicating the heli is ready, and connected to the transmitter. If it keeps flashing blue, either you forgot to switch on the transmitter (aka TX) or the heli is not "bound" to the TX yet or lost binding. How to (re)bind your TX and heli is listed in the "other problems" section.

When your heli is connected to the TX, and you apply throttle, a green led will start to flash on the receiver. This indicates the board is sending a throttle command to main and tail motor. This can help with trouble shooting. If the motors still don't turn with the green led flashing, either the ESC has gone bad, one or more motors are bad, or it might just be that the motor wires are not securely connected to the board.

Q 3: When I first start up the rotors, my servos move erratically, so it seems. When I power up just a few seconds later that doesn't happen. Is my board faulty?

A: No, don't worry. The reason for the servo movement is to help with lifting off straight from the ground. This lift-off-help-mix is part of the receiver's programming, and works quite well. And if you don't want to use it, spin the motors up slowly, and lift off when the servos have gone back to home position, which is just after some mere seconds.

Q 4: Is the V2 an updated version of the V1? ClubHeli even sells a "V5", is that even newer? And what about the Solo Pro I and II?

A: The V2 is not newer than the V1. The 2 indicates the color, meaning it has a yellow canopy and white skids, main blades and tail rotor. Apart from that the white parts are glow in the dark, a V2 is technically identical to a V1. The V5 doesn't exist, some sellers use it so indicate they've got the latest version. A "V5" is not newer than the V1 or V2. Same applies to the earlier versions of the Solo Pro, the I and II, the number only tells the color, not the specs of the heli, so the II is not better than the I.

As for the second question, the Solo Pro I and II are older versions. The main difference between the V-version and the older ones is the head (which will be discussed in the next question), the battery holder is "keyed" so you can't insert the battery the wrong way anymore, and the receiver has rotary pots instead of lineair resitive tracks on the receiver print. Also, between the receiver and the skids is now a connector, so when you have to replace one of these two, you don't need a soldering iron. As final differences, the tailboom is attached higher on the frame and is slightly longer. (check this posting for a comparison picture: )

It's very unlikely when buying one you will run into a Solo Pro I or II these days, even though some sellers may still use a pic of an older revision of this heli in their webshop. Also, the new parts were phased into produced helis, so it's possible to have a heli which is a combination of both older and newer parts, like for example a heli with a new head, but skids without the connector. Besides that, second hand helis might still be fully older spec.

Q 5: I heard there are different types of head used on the Solo Pro. What are the differences?

A: The main change is a different type of links between swash plate and mixer arms on the blades. The older head uses "banana" shaped linkages, while the newer head uses "o-shaped" ones. Because of this change the small thin pins on the top of the head, that those links rest against, are placed on a different location on the plastic head. So the new type of links won't fit on an older type head, at least not very well. If you want to use the newer links, you would also need a newer type main shaft set. Since the older type of head is no longer current, when getting a spare main shaft set, it is very likely it will contain the newer type main shaft, which needs the "o-shaped" links. The pictures below show first the old type head, and then the new type.

Q 6: There are these little tabs underneath the left skid of the landing gear. Did they forget to remove these “molding marks” in the factory?

A: These little tabs may seem out of place, but have a real purpose. Like we will discuss under the next chapter "Flight Behavior", this heli needs to hang to the right to stay in place. On the ground it would rest flat however. So when the rotors start spinning, the sideways push of the tail rotor might cause it to tip over before you managed to get airborne. To help prevent this, along with the lift-off-help-mix, the designers put these little tabs underneath the left skid to give it some right incline to begin with. So best not to remove these, unless you are willing to have to add some right aileron on every ground start.

Q 7: Why are there 2 types of balls on the top of the swash? Which ones should I use?

A: Stock the Solo Pro comes with the links attached to the long balls. These give more cyclic control. You could fit the links to the short balls, to tame response, but it is recommended to use the dual rates on the transmitter instead, to limit cyclic throws. These extra smaller balls are only present because the Solo coax uses these. Having both types of balls on the top of the swash means they manufacturer only has to produce one swash for both helis.

Q 8: I see these copper colored wires coming from the back of the receiver, but these are not connected to anything. Is that a problem?

A: Those copper colored wires are the antenna wires. These should only be connected to the receiver, and not to anything else. Also beware that they don't interfere with any moving parts. On the RX-01 receiver there is only one single antenna, so don't think it has fallen off.

Q 9: What is the purpose of those little square holes in the side of the canopy?

A: As you may know, the Bravo SX is also available in camouflaged version. For those who want to fit guns to their heli, Nine Eagles put those little square holes in the canopy's sides. The following pictures show this:

And those can fit right in:

Q 10: I have a good transmitter already (Dx6i, or other brand/type) can I use that to fly a Bind & Fly version of the Solo Pro?

A: Sadly, no. The 2.4 GHz technology offers some advantages over the older MHz types, but with it manufacturers decided to each use their own control protocol. As a result of that, you can only fly a heli from brand "A" with a transmitter (also referred to as TX) from brand "A", and not with one of brand "B". There is a way to fly a Solo Pro with the aforementioned Dx6i, but that requires replacing the complete receiver with the one from the mSR, which is Spektrum compatible. No easy task, and mSR recievers are about the same price as a complete RTF Solo Pro, if you manage to find a good deal.

Q 11: Can I control a BnF Solo Pro/Bravo SX with my current Nine Eagles transmitter?

A: If you previously bought the Solo coaxial, Bravo III or Draco, you can certainly use the TX that came with your RTF set to control a seperately bought Solo Pro or Bravo SX. This even holds for rebranded ones, like the Revell Proto CX for instance, you can use that transmitter to control a Solo Pro, rebranded Solo Pro, or Bravo SX. The more "hobby-like looking" Kestrel 500 transmitter (NE-24 TX) can also be bound to the Solo Pro series. This transmitter has also been seen bundled with the 220a Free Spirit.

Currently Nine Eagles is releasing a few new 6 channel TX model, with hopefully model memory and other advanced features. But it is not clear yet if these can be used to control the sub micro helis like the Solo Pro. The newer Solo Pro 270 uses a TX that is NOT compatible.

If you don't mind a little tinkering, this thread shows how to modify the popular Turnigy 9x transmitter to control the Solo Pro V and other helis using the same protocol:

Beware! Nine Eagles also make micro planes, and their TX looks just like the ones supplied with the helis, but you can't bind a Solo Pro to a plane TX, or the other way round. A very strange decision of Nine Eagles, so it seems, and the reason for this is yet unknown, but at the moment this is how it is.

Q 12: I keep hearing the Solo Pro is a "carbon copy" of the mSR and that Nine Eagles is getting sued for it. Should I avoid getting one?

A: Those that own(ed) both helis know they fly very differently. Head setup is very different, as is the battery connector, and the NE RTF transmitter is much more sophisticated. The lawsuit is based around a supoosed patent infringement on the lineair servos, and actually revolves around the mCX and Solo/Free Spirit coaxials, which were the first NE helis to use this servo type. However, it appears the company claiming the patent, and gets supported by Horizon Hobby to sue Nine Eagles, flied for a patent on this servo after the idea was already published, so the patent claim most likely won't hold due to the "prior art" principle. More details in this post:

Q 13: My heli came with a receiver marked "RX-01". Yet I hear that others fly with RX-06 or higher numbers. Did I get an old one?"

A: No, you didn't. For some reason, Nine Eagles did some funny things with the naming of receivers. The first Solo Pro receiver was RX-02, followed by RX-04 (A few reported to have a heli with RX-03, but so far this revision seems very rare), and later RX-05 (also quite rare) and RX-06. RX-02 and 04 have different servo design, with a linear resistive track providing feedback about the servo's position. These tracks were exposed to dust and debris, and also looked a lot like eFlite's servo design, so on the 05 and 06 rotary potmeters were used to provide feedback about the servo. 06 has the added bonus of a connector between skids and receiver, so you can replace either of these without soldering. Then it was decided to name the latest receiver RX-01, which is the current receiver type. Based on reliability, it appears the early RX-06 receivers are the best.

Q 14: Are the Jiuchon JC002 and the V911 also rebranded Solo Pro helis?

A: No, these are not. Both can be considered clones, with some changes here and there. Head setup is identical, and it appears even parts are interchangable. But there are also differences, on the Jiuchon the servos are not mounted on the receiver board, but on small seperate boards, the battery connector is the same the mSR uses, and the TX looks like a spitting image of the Blade RTF TX. The V911 seems to use a Trex 100S board and TX. Despite the close resemblence, you can't bind it to a NE TX, both clone use their own 2.4 Ghz protocol. For a more detailed description of both clones, check these reviews:

Jiuchon JC002:

For more information about the original Solo Pro, you might find these reviews helpfull. One is by Michael Heer, he reviews the Revell Proto Max, but since this is just a rebranded Solo Pro, the information is fully relevant. Here you can find the review:

The other review is about a Solo Pro V2: [url][url]

To give an impression of the flight characteristics of these helis, here are some videos hosted on Youtube.

Solo Pro:

Helitec - Nuevo modelo Nine Eagles SOLO Pro- vuelo en el campo con viento !!!"!!!! increible!!!! (1 min 45 sec)

Nine eagle solo pro.mp4 (2 min 1 sec)

Bravo SX:

nine eagles bravo sx (7 min 40 sec)

Flight Behavior

Important general remarks before (first) flight, please read this!: Since the linear servos used on this heli have mechanical limits, check if no servos are jamming or getting very close to jamming on full stick deflection. This test should be done on full rates, so with a "full circle" on the display of the transmitter, so you are getting the maximum servo throws. If a servo has less than 1 mm play at one of the endpoints, use the EPA-procedure, listed under the header "Trim Issues" for how to perform this adjustment. Observing this might save you a broken receiver board.

Second, it appears that a flight battery that is not making good contact with the battery terminals on the heli, can cause the receiver to get problems with the programmed endpoints, and a servo or possible both servos stop responding to stick movements. Instead they will move to full deflection of their own, and stay there, regardless of trim settings. There seems to be a way to recover from this situation, but prevention is usually better. If a battery doesn't make good contact, clean the metal strips of the connector on the battery with mild detergent, like 70% alcohol.

Small tutorial for new pilots:

When you are new to (single) rotor helis, take it easy on the first flights. I can't stress this enough, if possible, find a place where you have room to fly, like a big room, a hall, or even better, a gym. That way, when the heli starts drifting in one direction because it is not properly trimmed, you have time to react to this. In a cramped flying area, you will have to correct for a drift immediately, and most beginners tend to over-correct, making things worse, usually ending in a crash. And although this heli is light, and fairly crash resistant, it is not indestructable. For tips about trimming, you might want to check the second question of this part of this FAQ first. When you have the heli trimmed out, don't think about flying figures and fancy moves yet, you need to get used to the controls first. First, concentrate on how the heli responds to a small increase and decrease in throttle. When you get the hang of that, you could try a little forward movement (elevator), and then getting the heli back to you. Keep stick movements small, you want to keep control, instead of chasing the heli, and starting to over-correct. If you think you got an impression on elevator control, try a sideways ("aileron" or also called "roll") moving. Same as with elevator, make the heli slide left or right a little, and try to get it back to where it was. When you got that figured out, you are ready to try turning. Questions 3, 4 and 5 contain some valuable tips for how to make good turns, and question 11 explains how the self correcting ability of this heli might work against you a little as you start moving it around more. And remember, practice makes perfect!

Q 1: My heli is not hanging straight once in the air? I can't trim that out, is it broken?

A: This is completely normal. The sideways pressure of the tail rotor would make the heli slide left all the time, unless the rotor disc is tilted a little to the right to compensate this. So the heli will be, or need to be, trimmed a little to the right on the roll channel, and hence the heli does hang to the right in a stable hover. After a while you will become accustomed to this, and consider it normal. Most of these ultra small single rotor helis show this effect, and even bigger ones, but the heavier weight might reduce the tilt angle.

Q 2: How do I trim this heli for stable hover?

A: First, make sure you have enough space, so you don't run into a wall before you are ready trimming. Like we will see below this, the heli will move forward or backward when steering rudder. So the first thing to concentrate on is getting the tail to hold steady. You can do this in the air, or if you feel uncomfortable doing that, you could try "rough tail trimming" on the ground. Put the heli on a smooth surface, then carefully add throttle to a point where the heli will get a little "light on the skids" but can't take off yet. If the tail is badly trimmed, the heli will spin on the ground. Add some tail trim in the right direction to make the tail stop moving. The reason this could be called "rough trimming" is because the added resistance of being on the ground will affect trim.

When you (finally) get in the air, make sure you are well above the ground. If you are too low, the rotor wash will bounce back, and disturb the heli. Again, focus on the tail first, then, when this is holding well enough, take care of the other directions, like elevator (forward/backward) and roll (slide left/right) after that. This heli is so stable, you should be able to reach a setting where the heli will stay more or less in place without touching the TX's sticks at all. If you can't get a good trim, like a situation where 1 click one way is too much, and a click back again too little, check the chapter "Trim Issues" which is more to the bottom of this FAQ.

After trimming, observe if no servo gets too close to it's endpoint, sometimes when a lot of trim is applied, the endpoints setting gets altered a little, and this might be enough to get a servo to jam. If you have such an issue, either use the EPA procedure, or adjust the length of the pushrods instead of trimming on the transmitter.

Q 3: When I just right (clockwise) the heli accelerates, when I steer left (counter clockwise), it comes back to me! I am really just steering rudder, not moving other sticks, is my receiver programmed the wrong way or something else wrong?

A: No, it's not really a defect at all. This behavior is common for this heli. Reason for this behavior might be the strong tailrotor sideways push. This forces the heli to hang slanted in the air, like we discussed earlier. When you apply right rudder, the tail rotor increases sideways push, but also lifts the tail a little, because the heli is slanted. This makes the heli want to go forward at the same time. When applying left rudder, the opposite happens, the tail drops a little, and the heli comes veering backwards. There may be other forces involved, I don't have a degree in heli physics. Fact is, there are 4 things you can do about this,

a) learning to counter this behavior with some elevator input while applying rudder. Soon it will become second nature, trust me.
b) A more rigid flybar also seems to help, I've noticed right piros being quicker and more "on the spot" with my Xtreme sample flybar, even when not applying any elevator to compensate forward drift.
c) Put some weight on the tail (some wrapped solder strand or blue tack for instance) or alter the battery holder so the battery can be inserted with the connector facing forward. This shifts the center of gravity more to the back.
d) later in this FAQ there is a part that discusses altering the gyro setting. Lowering this setting improves yaw rate significantly

The Bravo SX also displays this trait, but much less noticable. It stays in much better place when steering rudder, turning almost like a coax would. It could be the different weight distribution also plays a role here, and the fuselage may also have some effect. The Blade mSR also doesn't seem to display this behavior, but that is because the receiver automatically mixes some elevator with rudder, to counter the sliding.

Q 4: I am having trouble making a left turn, even though I give some forward elevator, is something wrong?

A: Countering the tendency to drift backwards on a left turn with forward elevator is a must on the Solo Pro, but for a really smooth turn you need to do more. As you are now aware of, this heli leans to the right. To make it enter a left turn better, steer a little aileron/roll left at the same time as you give left rudder. This makes the heli lean left a little in the turn. Finding the right combination of rudder, aileron en elevator for a smooth left turn takes some practice, but if you persevere, you will get the hang of it.

Q 5: When I try to make a right turn in a tight space, the heli tends to slide out of the curve. What can I do to prevent this?

A: Although this heli is slanted to the right, helping in wider right turns, during a tight right turn it needs a little help. Adding a fraction of right aileron will keep the heli more locked in the turn.

Q 6: After a crash the heli is not stable in the air and goes all around the place. What is broken?

A: First thing to check is whether the orientation pin on the back of the swash plate hasn't jumped out off the slot that holds it in the proper position. If it is, just carefully bend the guide a little away, so the pin can snap back in. Look at the picture to see how a dislocated pin would look like. You can also use it to study if the links are all in the right place.

Also verify that both flybar weights are still present. Sometimes these pop out, and this causes a strong unbalance in the head. To prevent this, some have put a little shrink tube over the weights, to keep them in place at all times.

It can also be that the blade pivots have sheared off the head. How to fix this is covered under the header "repairs".

Q 7: Sometimes, when I go a little rough on the controls, I hear a loud "knack". Are the blades hitting something?

A: Well, there can be two things wrong. Either your tail fin has shifted forward, and the blades might brush along it occasionally. Or, more likely, it is the flybar hitting the canopy or tail boom. When you turn the blades so that the flybar is aligned with the tail boom, and you tilt it one way or the other, you will see it can touch the canopy top or tail boom, depending on what way you tilt it. This can also happen in the air. Solution is either very simple, be gentle with the controls, and you can most likely avoid it completely, like I have. Or shorten the flybar. Marconos posted an excellent video of one way to do that here:

nine eagles solo pro fly bar modificata.wmv (8 min 1 sec)

It appears that these collars, that are used on the Honeybee FP, fit very well: EK1-0269 (New 000238)

Ranavalona also did a nice job on his flybar. What he did was use the centre section of the stock one, with each end cut off 6mm beyond the root of the link arm and the stub scraped down to 1mm diameter. The outer arms are 1mm diameter carbon fibre rod, 40mm long (Can be as long as you like). They're joined by 12mm lengths of 1mm bore CF tube. At the end of each arm CA glue was used to attach a short 3mm bit of tube to act as an end stop. The weights are four turns of multicore solder - use more or less to suit - and they're covered with heat shrink tube to bring the weight up to where you want it. (Not strictly necessary.) Check the picture below for more details.

User Gabek also did a clean job on his flybar, as this picture shows:

There are other ways, when searching Youtube more ideas can be found. Most users report that, using stock weights, 95 mm is the best length, shorter can cause instability.

Recently, a company called Xtreme, has started work on a flybar that looks very similar to Marconos' modded one, but with carbon fiber as rod material. I have had the privilege of testing a sample, and first results seem very good. Still, as long as it hasn't been put into production, and we don't know what it will cost, the best way to prevent strikes is by being gentle on the sticks or mod the flybar yourself.

Q 8: When I switch the TX to outdoor/advanced mode, both servos move when I push the elevator stick full forward. My board must be defective...

A: Well, it is your board, but it's not defective. When you check the text on your board it will read "RX-04" somewhere. This type of receiver was used in later revisions of the Solo Pro I and II, and has a special aileron/elevator mix that is activated in outdoor/advanced mode only. When the elevator servo moves down, at a certain point close to full travel, this mix will be activated, and aileron servo will steer almost full left as well. When this happens in FFF, the heli will veer a little to the left and loose speed as well. The reason for this mix probably is to counter what is called "translational lift", the effect that helis tend to want to roll to one side when the forward speed increases. This is caused by a difference in lift between the rotor blade that moves towards the front of the heli, and the one moving to the back of the heli. When in hover, there is no airflow over the blades except the one caused by the blades' rotation, so the lift force is equal on every part of the rotor. When moving forward with decent speed, the blade moving forward will have increased airflow, while the one moving back gets less airflow, and as a result less lift, just like a plane trying to land or take off with the wind from the back. This results in more lift on the left side of the rotor disc, and less lift on the right side. This unbalance in the lift makes the heli roll right in case of a clockwise spinning main rotor, like on the Solo Pro, and this causes the heli to want to make a curve to the right as you go into FFF.

On later revisions of the receiver, the aileron mix to help with FFF was left out, probably because it didn't work out as intended. So you will have to add a little left aileron yourself when going FFF. Also, it would help to trim your heli to drift very, very slowly left when in handsfree hover. This will counter the roll to the right tendency up till a certain speed.

So to get rid of this mix, you can either replace the receiver (RX-06 also has faster servos that are better shielded from dust as added benefit) or use the EPA procedure (listed under "Trim Issues") to limit forward travel of the elevator servo, so it can never reach the point where the mix gets triggered. When you do this, make sure you also shift the center position of the elevator servo up, with subtrimming (also listed under "Trim Issues") or you will loose forward elevator travel, and your heli will be slower in forward flight.

Q 9: When I want to take off, the heli tips over to the side. What am I doing wrong?

A: Chances are you are not adding throttle fast enough. Best is to move the throttle stick fairly fast to around 50%, which is usually where the heli wants to climb a little on a fresh battery. Don't punch the throttle to full or you will be up at the ceiling in a second (unless you are flying in a nice open space) and down on the ground the next second. You could also opt for the hand launch technique. The Solo Pro video at the bottom of the "First Impressions" section, shows this method. Basically it means holding the heli in one hand, at the point where the tail is attached, and the transmitter with the other hand. Add throttle till about 50%, and you will feel the heli wanting to go up. Then gently release the heli, and take the transmitter in both hands, to start flying.

Q 10: Every time I land my Bravo SX the heli tips over backwards. Is there a way to land it nicely?

A: The Bravo SX has it's weight more to the back, making it a little tail heavy. This causes trouble with landing. First thing to check is if you got the right battery with your heli. Some RTF kits, both Deluxe and standard ones, were bundled with the "plane-battery" with the wrong label on it. This battery is 4.70g instead of 4.35g, and this will shift balance even more to the back, and reduce flight times a little.

If you have the right battery, there is a technique to help. Make the heli descend smoothly, like usual, and when the skids are about to touch down, apply a touch of forward elevator. Small stick movements are the key, and with practice you can make every landing a "scale like" one.

Q11: This heli seems to have a mind of it's own. When I give forward elevator, and then center the stick again, it comes backwards a little. What is going on?

A: As you may or may not now, this heli has a 45 degrees shifted flybar. This head setup gives the heli it's stability and the ability to hover handsfree, and stay in position, not taking air disturbances and other outside influences into account. This also means the flybar tends to counter your control inputs. So when you give forward elevator, the flybar will try to get the heli back to steady hover. However, the cyclic controls have more "steering power" than the flybar, so the heli will move forward, with the flybar still fighting this movement. When you return the sticks to zero, there is no cyclic input, and the flybar, which was trying to stop the heli, will cause it to move backwards a little. This can be annoying, although the effect is quite mild on the Solo Pro, on some helis this effect is even more pronounced. Best way to prevent this "backfiring" is to ease the stick to the middle, instead of moving it abruptly to neutral. That way, the heli will come to a halt without any side effects. It may take some practice, but since smooth stick inputs are what most helis need anyway, it's a good moment to start with it now.

Q 12: I have a Bravo SX, and sometimes it wobbles during flight. What is wrong, and can I fix it?

A: This behavior is seen on some Bravo SX helis. This wobbling can show itself when for instance making a fast left piro, and then centering the sticks, so the heli goes back into stable hover. During the transition to hover, a rocking movement can be seen. Sometimes it's also present when giving left aileron. It's no regular inbalance in the head, since the heli still has the ability to do a steady hands free hover. If you also have a wobble when not touching the sticks, and the heli is in hover, you have another problem, and you should fix that first. If the wobble is only present in transition to hover and/or when giving left aileron, there are a few thing you can try. Some have been able to fix it by altering the gyro setting. This procedure is listed under "Trim Issues", the third question. Most of the time the gyro needs to be increased, try 2 to 3 clicks and see what the results are. If needed, try some 2 to 3 clicks more. It might be wise to record how far you adjusted the gyro, so you can go back to the original setting, if the adjustments don't improve things. It could also be that on your heli, the gyro needs to be decreased a little, instead of increased.

Others have reduced the lateral play on the blades. A little picture explains this:

By adding a small washer on one, or both sides, limiting lateral play, some reported the wobble was fully gone. Make sure you don't reduce play too much, and cause the blades not to pivot freely any more after adding the washer(s). Another possible option is to loosen both screws that hold the blades together, and tighten them again while pushing the blades to the center, so they get fixed with less play. This method is still under investigation.

Q 13: I have a Bravo SX, and after a couple of flights my flight times have dropped dramatically. The heli seems to loose power. What is the matter?

A: Recently, we're talking june 2011, there seem to be some issues with some batches of Bravo SX main motors. This can show itself after a few flight, or even on the maiden. You may be able to fly well for a minute or so, and then power drops rapidly. Or, at the beginning of the flight, when going to full throttle, a strange sound can be heard, like on the following vid:

The only way to solve this is replacing the main motor, hoping it will be from a good batch, or claim warranty.

Q 14: Sometimes I need to start my main/tail motor manually, giving it a little tap. Is that normal?

A: Definitely not! This type of motor should be able to start from any position of the axle. Having to "crank-start" a motor means it has been damaged, most likely the brushes and collector, and should be replaced ASAP! You risk burning the main or tail motor ESC transistor, depending on which motor is going bad. Other symptoms might be the heli losing bind as soon as you throttle up.

Q 15: My heli barely moves forward when giving forward elevator. What is wrong?

A: This problem can be caused by a number of things. First to check is if the elevator servo has decent forward throw. If not, check the "trimming" section of this FAQ how to adjust the servo's throw. Also check if the TX is on low rates, as this reduces throw. Also, sometimes the heli needs a little push to make the nose dip down, and gain speed. You can help the heli doing this by adding a little throttle while moving the elevator forward. Finally, it might also be caused by the little collar beneath the swash plate, that holds the main shaft in place. If it comes loose, usually because the area around the screw has cracked, the main shaft can move up and down, and most of the forward elevator movement goes into sliding the shaft down.


General remark about repairs: If a part is not secured by any screw(s), you can assume it is press-fit instead. Like the tail rotor, landing gear and tail boom. When you need to remove such a part, pull gently but firmly until you feel the part coming loose. Never use considerable force, it's still a small heli, and though quite durable, things can break if you try to rip it apart.

This link gives a step by step tutorial on how to assemble a Solo Pro, it might be helpful as reference during repairs:

Also, I keep getting questions where to get spare parts. I will provide some options here, but stress that these are not the only vendors offering Nine Eagles (compatible) spares, and if you run into troubles with one of them, I don't feel responsible for "guiding you there". Possible sources are:

ClubHeli -
Miracle Mart -
HopMeUp -
My RcMart -
Hobby King -

Also keep in mind that rebranded helis use the same parts, so look at all your options to see which one offers the best deal for you.

For those who feel capable of soldering on SMD components, and have a problem that is related to a failed component on the receiver board, this posting might be a useful reference:

Q 1: What spare parts do I need for this heli?

A: Depends on your flying style and luck. If you don't crash you will simply wear some things out sooner or later. The tail motor is usually the first to go. The links between swash and head will wear as well, and may unsnap themselves during flight, so it is wise to keep a linkage set handy. The main motor may also go sooner or later.

Different story when you crash often, you might need a lot more spare parts, although most of the times because of it's light weight, a crash may not cause any damage at all. Things that can break are

- the landing skids
- the main shaft (blade pivots shear off, a little below this we will discuss how to fix this cheap)
- possibly a flybar (It won't break easily, but the weights could come loose, and will naturally be hiding somewhere after that... )
- canopy (doesn't really need to be intact to be able to fly, but it might look ugle when cracked)

Q 2: My heli came with the tail boom loose from the frame. How do I put it back on, where do the wires go?

A: The tail boom is, like most parts, pressed in. Sometimes it isn't pressed in far enough in the factory, or get's loose during transport. It's easy to push it back in, if you know where the wires should go. On the left side (viewed from behind) of the socket in the frame, that the tail boom is supposed to be, there is a small groove, where the wires can be routed backwards to the end of the socket, and go from there to the receiver. Here's a picture, to clarify things:

If the tail has a loose fit, and slides out during flight, secure it with a drop of (hot) glue.

Q 3: After a crash one servo is binding and buzzing.

A: This could be caused by a number of things. This list (provided by member asanado) may help:

Verify that:

- Threaded axle is straight and clean, and rotates freely (about 1/2 mm play).
- Axle has a good thread (not damaged).
- Plastic rail (in which the moving part of the servo slides up and down) is straight and not deformed. (check screws holding it to the board)
- Gears are whole, no missing or deformed teeth, not cracked or broken.
- Lever between servo and feedback potmeter is in place and moving freely.
- Servo Links are not touching the canopy.
- Endpoints are not exceeding mechanical limits, aka the servo travels too close to the edge and jams as a result.
- The feedback potmeter has no cold soldering points. When in doubt, use a soldering iron with a thin tip to reflow the points.

This is all assuming board (servo MosFets) is not damaged. In that case you would need to replace SMD components, which is no easy feat.

Q 4: Can I use spare parts from other helis? I broke something and the local hobby shop has no Nine Eagles spares...

A: Well, you can in some cases. The tail rotor of the Blade MSR is a direct replacement for the Solo Pro tail rotor, and if you can solder those tiny wires, you could even use a tail motor of the same heli. Some reported the tail rotor from the well know Picooz can be used.

Also some parts from other Nine Eagles micro helis will fit. The locking collar on the main shaft is the same as the one used in the Solo/Free Spirir coax. Also the links between swash and mixer arms on the blades are the same, if you have a Solo Pro V1 or V2 with the O-shaped links. And even the swash can be identical. The one on my Solo coax also had longer and shorter balls on the top plate, but beware, there are also some coaxes, in my case a rebranded Solo (Merlin Tracer 60) that had 4 short balls, so you will lose cyclic control when taking a swash from that one. The tail of the 270 doesn't fit, as it's a fraction thicker.

Q 5: One of the pins that holds the landing gear to the frame snapped off, and is now stuck inside the hole in the frame. I can't get it out, help!

A: This seems like a tricky situation, but there are a few ways to get the remainder of the pin out. You can use a smal drill bit to drill a little hole in the broken piece and then thread a small screw into it as far as possible. Then pull the whole thing out with pliers. Another method is using a heated paperclip, or a another small metal pin, and press it into the broken piece that is stuck. Let it cool down, then pull it out with pliers.

Q 6: The links between swash and blades keep coming loose in flight. They also snap on very loosely, but I don't have a spare linkage set...

A: The little holes in those links wear out sooner or later, no doubt. Besides replacing them, there is a way to repair them with thin CA glue. Get a thin object, like a toothpick or small flat screwdriver, put a tiny drop of glue on, and make a circular motion inside the hole that has a too loose fit, coating the inner sides with a thin layer of CA glue. Let this cure for a good period of time (we wouldn't want the glue to be a little wet and then find out the links are permanently glued to the swash plate and mixer arms, no do we?) and then fit them back on. If there is still too much play, repeat procedure, but usually one time can fix this link for many flights.

Q 7: I broke my flybar and can't remove it to replace it. Help!

A: The metal pin holding the flybar is press fit. Essential is that you have something to push it out with, something small enough to fit in the hole that the pin sits in, without getting stuck or damaging the inside of the hole. Try to get a small flat precision screwdriver, put that on the pin, and gently but firmly press while holding the head with your other hand. The pin is only held in place by the flybar, so you only get resistance from that. Don't use force, but even pressure to slide it out.

Some have used a jewellers watch strap pin removal tool to extract the flybar pin. These can be found on sites like eBay if you search for "watch strap link pin". It uses a screw movement to gently press the pin out.

Q 8: My blade pivots sheared off in a crash. Can I glue them back on?

A: You can try, but it won't be very strong. The only other way to save yourself from getting a new main shaft is to replace the sheared of plastic pivots with a new pin. This can be done by drilling a hole on the place where the sheared off pivots used to be, straight through the shaft. Make sure that the drill is perpendicular to the shaft, so the hole on one end will line up with the other side. This video shows it quite nicely:

nine eagles solo pro mainshaft repair (6 min 26 sec)

You can use alternate materials for the replacement blade pivots, some used tooth picks, others used a straw from a spray can, or a metal pin. The results are comparable, but a weaker material like tooth picks will work like a fuse, breaking in crash, and hopefully saving other parts from harm. A metal pin will not break, but perhaps something else will. What you choose, depends on what you want from the final result.

Important!: Should you decide to replace the main shaft, observe the position of the little collar beneath the swash. It should have the ridge facing down. Mounting it the wrong way will cause trim problems.

Q 9: I had to replace the receiver and it came without wires attached. Where do the wires from the battery connector go?

A: On the bottom right of the front side of the circuit board (the side where the servo motors are) you'll see 2 solder pads marked "B+" and "B-" indicating battery positive wire (red) and battery negative wire (black) placement. The next picture will show this.

This picture shows a Bravo SX board on the left side, explaining the extra wires (from the navigation lights) and a Solo Pro one on the right. The solder pads on the receiver are quite small, so you might want to practice first if you don't have much experience with soldering on such small objects. It might help to remove the right servo motor on the picture, to give more clearance.

Q 10: When I try to put the linkages back on the balls, they won't snap on again. What is wrong?

A: Sometimes the fit can be a little tight, but it might also be that you are trying to put them on the wrong way. Every link has a bigger hole on one side, and a smaller on the other. Observe this, and always put the bigger hole on the inside.

Q 11: How do I get the canopy off?

A: On the Solo Pro this is fairly easy. The canopy is held on the frame with 4 rubbery washers, that sit on the connector pegs on the frame. Simply put your finger on the inside of the canopy near the connector peg, and slide the washer off, taking that part of the canopy with it. The canopy is made from very flexible material, so if you do it gently, nothing will get damaged.

The Bravo SX is more of a challenge. The canopy is held by 6 pins on the frame, 4 of which are secured with screws. Near the "exhaust" on the bottom of the heli is a 5th screw, and on the front there are 2 more, one on each side, holding the searchlight. To seperate the canopy halves, only one has to be removed. Also on the front, just before the swash plate, is another screw, joining the canopy on the top section.

The biggest challenge comes next, the windshield is partially glued with CA, as well as the top section directly behind the main shaft. The only way to get this apart cleanly is with a thin knife, putting between the parts where the halves are not glued, and then driving it towards the glued parts. Gently does it! If you have the right tools, apply the right amount of moderated force, and a little luck, you should be able to seperate the windshield and other glues areas without any damage. If you need to fully remove the canopy, there is also a screw near the tail motor to be removed. For maintenance on the receiver this can stay where it was. Installation is the opposite of removal, just observe all holes in the canopy and pins on the frame are lined up when joining the halves. It's easy to miss a pin, and then the canopy will be warped, and not fit well

Q 12: How long do the motors last? And how do I replace the main motor?

A: The motors can last pretty long when treated well. Most motors die prematurely either because of crash damage, or not being allowed to cool down between flights. Luckily replacing the main motor, just like the tail motor, is a fairly simple procedure. The motor is just press fit in the frame. There is a small dot of glue securing it, but with a little pressure the motor will slide out quite easily. It is convenient to remove the canopy and skids, so you have more clearance on the bottom. Unplug the connector but observe how it was connected. If you forgot to take a picture, or note it down, the red wire is on the bottom. Just the opposite of the tail motor, on which the reddish wire is on top. Use a blunt screwdriver or other strong thin pointed object to push the motor up. It may help to disconnect the links to the swash, although it can be done with them still on, so you don't risk snapping off the balls on the swash. Replacing the motor with a fresh one is just a matter of pushing it down in the slot. You could put a drop of glue to secure it, when in place, although it is not really needed, it sits pretty snug.

Q 13: Can I use the receiver of the small coaxials? It looks very much like my current receiver.

A: No, not really. The programming on the coaxial receiver is different. A coaxial turns by speeding up one rotor/motor and slowing down the other. Also, the gyro affects both. With a single rotor setup, rudder is only achieved by speeding up a single motor, the tail motor. With older revisions the receivers used in the coaxials used a different layout, and the gyro was mounted differently, so you could easily tell both receivers apart, but since the introduction of the "universal" RX-01 receiver, they look identical. But the programming is different, so unless we find a way to re-program a receiver, it can only be used with the heli type it came with.

Q 14: A small plastic part (see picture) fell from the heli. I have no idea where it goes, or if it has a real function. What can I do?

A: This is the part that you mean, right?:

It belongs near the battery contacts, holding those in position. A picture of the white skids clearly shows where the part goes:

Like most parts, this is just press-fit, but you might consider securing it with a drop of glue, since it doesn't have to stay removable.

Q 15: Suddenly, or right after a crash the heli keeps spinning. What can I do?

A: Usually, a spinning heli means tail problems. If, when viewed from above, the rotation is counter clockwise, the tail motor's connector might have loosened itself from the receiver board, or is making bad contact. It's also possible a hair was trapped around the tail motor's axle. Make sureAlso the tail rotor hasn't cracked at the root of the blades, and is now slipping on the axle. If the motors were still spinning when crashing, it also possible the tail motor's axle got bent, or the motor got damaged. If you hear distinct clicking sounds when manually rotating the motor, the brushes might have been damaged, and you will need a new tail motor. Generally, it's very wise to always keep a tail set as spare, for easy trouble shooting and fixing.

Sometimes you get the opposite, the heli rotating clockwise when viewed from above. This means the tail motor is overpowering the main rotor's torque. Most likely cause is a blown transistor in the tail motor's speed control (ESC) section. If you have experience with electronics, you might be able to replace the damaged part. User "asanado" created a comprehensive "how to", just take a look at this posting:

Except from taking a transistor from a damaged board, this posting lists some compatible components:

If you don't feel comfortable with SMD soldering, or can't find anyone to do it for you, only fix is a new receiver board.

Q 16: When I throttle up the power is suddenly lost. Can also occur when moving the servos. What is wrong?

Most likely the contact between battery and receiver board is not ok. It could be that the small strips inside the battery holder on the heli have become a little dirty, or bent backwards too far, so these don't make good contact with the battery. It can also be that the battery's metal strips have become a little smudgy. A drop of cleaning alcohol on a cotton stick would be a good way to make these contact shine again.

A final option is that the problem lies in the wire that runs from battery holder to the receiver board. On some heli's this wire hangs a little low, and when inserting the battery, it pushes against the wire. This can cause breakage, or the wire getting loose from the receiver board. After taking off the canopy, this will be easier to spot. If touching the wire causes the leds on the board to flicker or go dim, there is your problem.

Another possible cause, if it only happens on throttle input, and not with moving the servos, is that main and/or tail motor is failing. A bad motor can cause excessive current draw, and thus a brown-out. If you don't have a spare motor available, try unplugging either tail or main motor, and check if the power issue is gone with one motor disconnected. If it is, you will likely need a new motor.

Q 17: Where can I find spare connector wires to connect the RX with the skids?

A: Nine Eagles doesn't seem to sell the wires with plug as seperate spare parts, user Sar315 found this connector is the JST (ZHR-2P) type plug. For more information, check this posting:

Q 18: Suddenly a servo moves to full travel on it's own and stays there. I can manually rotate the axle to bring it back to the middle, but as soon as the heli powers on, it moves to full travel again.

A: There are 2 causes most likely. If the servo stays centered when only the heli is powered up, but moves to full travel as soon as the transmitter is switched on, it's probably a problem with the endpoints setting. Enter EPA mode, and then try to increase the range on the opposite side of where the servo is jamming. One would expect the endpoint on the side where the servo has moved to be wrong, but in fact it's the other way 'round, the lower endpoint has probably moved up and is now above the other endpoint. The servo wants to sit in the middle, so tries to reach it's new midpoint, and jams, as it moves the wrong way.

A second problem might be with the feedback potmeters on the board. Like mentioned earlier, with the "servo's binding or buzzing" issues, there may be some cold solder joints, causing a wrong value about the servo's position to be reported back to the board's logic. In this case, the servo might not stay centered as the heli is powered up without the TX being on, but this needs to be verified.

Q 19: The tail wires seem like these can cause a short any second, as there is no insulation. Do I need a new tail?

A: Don't worry, the wires are fully insulated with a thin coat of enamel paint. Unless this layer gets damaged there is no risk of shorting. However, as the coating is translucent, damaged insulation may be hard to spot.

Q 20: My heli keeps rebinding/restarting. What can be wrong?

A: There are a few possible causes. A loose connection in the power supply, like a damaged or badly soldered battery wire, bent contact strips on the battery holder. A damaged motor can also cause this. Try unplugging the main and tail motor, to see if the problem goes away. If it doesn't, it could also be a bad servo motor, unsoldering one of these might help identify the culprit. If the issue is intermittent, fixed it before flying on, as you risk burning board components.

Q 21: Are there other skids that can be used instead of the stock skids?

A: Besides the parts of rebranded helis, there are some other options for the Solo Pro I/II/V1/V2. First, the skids of the same size Nine Eagles coaxials will fit. The battery will be mounted 180 degrees turned, though, which will reduce the forward bias of the Solo Pro V. So expect less forward speed, but possibly more neutral rudder response. The 270s skids fit as well, and will look better. These also have the battery facing to the rear, so it will affect handling.

As the Bravo SX uses a different spacing between the mouting pins for the skids, without modding, no skids of the other NE helis will fit.

Part 2 of this FAQ is located in the post directly below this one.

Big thanks to all who contributed. This FAQ wouldn't have been possible without your help.
Last edited by SoloProFan; May 11, 2016 at 06:29 AM.
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Nov 11, 2010, 03:02 PM
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FAQ Part 2

The first posting was starting to exceed the 60000 characters limit, so I had to split the FAQ up into 2 parts.

Power Options:

Q 1: How long can I fly on a battery, and how do I know when to land?

A: Depends on the battery capacity. With the stock 120 mAh cells you can stay in the air for around 7 minutes, but these don't last many cycles. With Hobby King's OEM 120 mAh batteries flights of 6 1/2 to 7 minutes are possible, and these seem to last more cycles. Also remember lipos need to be treated with care. Discharge them too far and they won't last long, and in worst case scenario can explode or catch fire. The lipos for the Solo Pro are small, so the risks are also smaller, but you still don't want to go too far, and destroy your batteries. When the heli can't hold altitude on full throttle, you will have gone too far. Best is to either time your flights or use the throttle percentage on the display of the transmitter to estimate the condition of the lipo. Between full and a well but not overly discharged lipo, there is about 20% throttle. So if in the beginning you need say 45% throttle to maintain height, it will be time to land at 65% throttle to maintain height. If you want to be extra careful, take 15% as stopping point. This will be about 5 minutes of flight, 20% will be a little over 6, depending on battery capacity.

The Bravo SX draws more power from the battery, due to it's higher weight and navigation lights. Typical flight times for this heli are 5 1/2 minutes with a 150/160 mAh battery. With the Hobby King 120s you can get a little over 4 minutes. Due to the higher current drain you probably won't reach the 20% throttle difference before the heli starts to spiral down because battery voltage collapses. Either time your flights to 5 minutes, so you have some power left to land, or let "throttle needed to hold hover" drop between 10 and 15% max to prevent an unexpected landing at the end of the flight.

Q 2: Can I fly batteries back to back, so directly after one another?

A: Flying batteries back to back is not recommended, at least not indoor. After a typical 5 to 6 minute flight in the living room, which will consist mainly of hovering, the tail motor will feel quite warm. And you can be sure the inside of the motor is much hotter. A cool down of 5 to 10 minutes is recommended in this situation. Outside it may be different, since the heli moves through the air, and motors don't heat up so fast, since the air cools them down. On a hot summer day the same rules like for indoor flight might apply, but with temps around 20 degrees centigrade or lower, 2 batteries in a row, or perhaps even more, will not heat up the motors very fast.

Closely related to this question is using a higher cap battery. One thing to observe here is that a bigger battery will make the heli heavier, putting more strain on the motors, which might make them heat up faster. Best option for a bigger battery is currently the Thunder Power 160, which is about the same weight as a 130 mAh cell, just 4.0g. But this battery doesn't come with a Nine Eagles style connector.

Q 3: How long does it take to charge a battery?

A: That depends on how much was drained from it the flight before. And this is also determined by what heli you used it in. The Bravo SX draws more power than the lighter Solo Pro. I did some measurements and found that for about every minute of flight on the Solo Pro, you need about 5 minutes to charge back what was used from the battery. So if you were to fly for 4 minutes, charge time would be around 20 minutes to get it fully charged again. On the Bravo SX the ratio is different. For every minute of flight you will have to charge the battery for 7 minutes. This is using the NE wall charger. Results may vary a little, as some chargers might have a higher or lower charge current, and it also depends on your flying style. My typical flights consist of a little hover, some turns or circuits, some nose or tail in circles, and sometimes a little precision landing practice.

Q 4: I bought a new battery and it won't fit my Solo Pro I/II.

A: That is very well possible. Nine Eagles changed the connector slightly when introducing the V-series. Since the Solo Pro has the battery inserted the other way round compared to the coaxial Solo, some inserted the battery with the connector facing forward, and fried their receiver instantly. To prevent this, Nine Eagles added an extra "key" notch on the new batteries, making this impossible. If you have an older Solo Pro, though, new batteries, like the OEMs from Hobby King for instant, won't fit. Solution is simple, remove the extra notch (and in case if the OEMs, also file or sand down the edges of the connector, because it's a fraction too big) and the battery should fit well again.

A picture showing a V-series battery and an older one side to side:

To make things a little more confusing, the Bravo SX uses the old style connector again, since the battery is also inserted with the connector facing forward, just like on the coaxial Solo. To make a new battery fit the Bravo SX, the same applies as when making it fit an older Solo Pro, remove the extra tab on the connector, and it will fit your heli again.

Q 5: My batteries are getting a little puffy and don't perform very well any more. What is wrong?

A: Lipo batteries need to be treated with special care. In contrary to some other types of batteries, like NiCad, these should never be fully discharged, but kept above 3V, and preferably higher. When you do push flight times to the limit, you risk over-draining the lipo battery, which might cause irreversible damage. Lipos also don't like heat, and when a battery gets close to being fully drained, it will get hot fast. When subjected to this kind of abuse, the lipo will get puffy, and perform less. The first question in this chapter gives some guidelines on how to treat your batteries the right way.

This can also happen when the used lipo is not able to deliver the current the motors are drawing from it, and also gets too hot during flight. The stock Nine Eagles 120 mAh batteries suffer from this, and will get puffy even when treated with proper care. Other batteries are a better option. The stock 150 mAh lipo that comes with the Bravo SX seems to hold up much better, despite the Bravo SX drawing more power from the battery.

Q 6: What other batteries can be used with the Solo Pro?

A: Because Nine Eagles uses a battery connector of their own design, options were very limited until recently. You could only use stock batteries without modding. But Hobby King recently started selling OEM batteries that are much cheaper than stock ones. Despite their low C-rating, implying they are not suitable for high performance use, they actually work quite well. Flight times of over 6 minutes for the 120 mAh version, and even longer with the 150 mAh type, with good power, and they can easily reach over 100 cycles, when treated well. In the next question, just below this one. you'll find some info about things to do before using these batteries, please read them as well if you got the OEMs. The graph directly below this shows how these perform, when compared to the stock batteries:

As of november 2010 Hyperion also sells their 130 mAh batteries with NE connector, so perhaps Intellect will also, which is a battery with identical performance, but usually a better price. If you want more power than stock or the OEMs, but don't want to mod batteries or your heli, this is certainly an option. Fall 2011, Hobby King started fitting the Nanotech 130 and 160 mAh batteries with NE connector, providing another way to get more power, but at a more economical price point than Hyperion. The Nano 160 is a little on the heavy side though, with 4.8g. Personally I would prefer the lighter 130 mAh, rather have to change the battery a little more often, but have a more lively responding heli, than adding almost 1g over the weight of a stock battery. The Nanotechs come with 2 types of connector, T2 (twin rail) and T1 or single rail. The Solo Pro uses the single rail type, the Bravo SX the twin rail. However, it's relative;y easy to remove those rails, so it's possible to use both types in both the SX and the SP. The only reason for the difference in connector are to prevent inserting the battery the wrong way, so you have to be more alert when making batteries suitable for both helis.

Do you want more choices, it is better to solder an extra wire to the skids' contact strips so batteries for the MSR can be used. Intellect/Hyperion 130 mAh is very suitable, and the Thunder Power 160 and Nano-tech 130 are other possible options, although these haven't been tested as extensively yet. The extra wire can be found here:

And the picture right below this indicates where the wire should come. Remember to sand the metal strips a little so solder will hold better, and don't apply heat for too long, or the plastic will melt. You can also decide to solder the extra wire directly to the receiver, but this also has risks involved, since the contacts are close to one servo motor, and some small SMD components...

For those that are comfortable with dissecting lipos, it is possible to replace the MSR style connector with a NE type, of an old faded stock battery for instance, and get a better electrical contact, with more power. There are some risks though, so try at your own risk, and take precautions.

Q 7: I bought those OEM 120 mAh batteries from Hobby King but they won't fit or the heli won't turn on when the battery is in place. Cheap crappy batteries?

A: These batteries are quite capable, but have 2 things to observe before use. First, some contamination can be present om the metal contact strips of the battery's connector. So it is advised to clean these before inserting the battery. Take a cotton swab and some cleaning alcohol, and rub the contacts a few time. You'll see them become shiny, where before they were a little dull looking.

Second, it might be you have an older Solo Pro, that won't accept batteries with the V-series connector. Go a few lines up, and you'll see the "My new battery won't fit my Solo Pro I/II" header.

Third, the OEM 150 has the pull tab on the wrong end for use in the Solo Pro. Solution is simple, either make a new pull tab from tape and attach it to the connector side, or remove the current pulling tab, and re-attach it to the connector side.

Fourth, the corners on the connector of the OEM batteries are a little too sharp, and need to be rounded off some to make them fit as smoothly like a stock battery. A small precision file, like one that is used for fingernails, will do fine. The picture below shows what corners need some trimming. Use a small file or hobby knife to round of the indicated sharp edges. Test fit regularly to see if fit has improved enough. Picture only indicates this for one side, but repeat procedure at the other side for best results. It may take a few minutes, but these batteries perform well enough to warrant the extra effort in making them fit perfectly.

Q 8: Okay, so now I have some batteries with Eflite style connector. Can I use my NE wall charger to charge those?

A: Oh yes, you can, but it requires some modding of either the charger or using an old battery. Modding the charger is quite straightforward, open it up, and solder an extension wire, like you used in the heli, to the terminals inside the charger. Red is + and black is - like is to be expected. Make a little hole in the charger's case for the wire to pass through and close it again.

There is also a method that leaves the charger untouched, but like I said, uses an old battery. You need to remove the connector from the battery, and then solder the extension wire to the terminals inside the battery connector. Other benefits are that you can easily measure the lipo's voltage, since a multimeter can be used to make contact with the NE connector's contact strips. Here are some pictures to clarify this method:

Q 9: Can I use rechargeble batteries in the transmitter?

A: You can, and when you use the transmitter to charge the batteries of the helicopter it might be wise. Just beware that voltage of rechargable batteries (unless you have alkaline based ones) can be lower than of standard, one time use, batteries. Better is to charge the heli's batteries with the Nine Eagles wall charger, and just put alkalines in the TX. Flying this way, I am still on the TX batteries my heli came with, and do fly regularly. Just watch the battery indicator on the TX's display carefully. When you have just one segment lighting up, it might be wise to change to a fresh set of batteries, to avoid range problems when flying outside. This may even apply to inside, since some devices in your house can interfere with the 2.4 Ghz signals your Solo Pro uses.

Q 10: My TX "eats" batteries, is something wrong or why does it consume so much energy?

A: My guess is you are using the TX to charge the heli batteries. This will deplete them very soon. If you use a wall charger for the lipos, and just use the TX for controlling your heli, batteries can last up to months, even with daily flying. The AA batteries that came with the heli might last a little shorter, since these are not high grade, but regular brands, that have a good reputation, will last much longer.

Q 11: I have a Revell Proto Max and use the TX to charge the lipo. According to the manual the charging light should go off when the lipo is fully charged, but it starts blinking instead?

A: This seems to be an issue only with the Proto Max batteries, which have a little Low Voltage Protection circuitry built in. Jtravel asked someone at Revell directly about this, and it was confirmed a blinking light means a charged battery, so the manual is not fully accurate there. Some users report that the light will go out a while later, but based upon current information you should remove the Proto Max battery when the light starts blinking. If you want to be sure the battery is fully charged, test with a voltage meter, it should read around 4.20V, might be a little higher when just coming of the charger.

Q 12: The Nine Eagles Wall Charger is out of stock everywhere, and I am going nuts having to use the TX to charge my batteries...

A: Don't despair. There are other options. You can use the skids of the Solo coaxial, or other NE heli that uses these batteries, and a spare USB charger you might have lying around from some 3 channel infrared coaxial. If not, these USB chargers come cheap. Their charge rate is mostly close enough to the NE charger, and they have a cut off around 4.2 Volt, although some chargers have no cut off, since the overcharge protection is located on the battery in the heli the charger came with, and are not suitable as a result. Here's a picture that shows how you can do this:

You can also use these skids to connect the batteries to a bigger charger, that has adjustable charge rates, and use that instead.

Q 13: I noticed there are different versions of the Wall Charger, which one do I need?

A: Because NE changed the connector slightly with the V-series of the Solo Pro, to avoid inserting it the wrong way, and shorting the receiver, the charger's socket was also altered. But if your charger looks like the one on the picture, it will accept all current NE micro batteries.

If you do get a charger that has small slots on both sides of each charge socket, and have V-series batteries, you can either remove the bigger notch on the batteries, or modify the charger, by using a file to enlarge the left notch, whatever you like best.

Q 14: When inserting a battery in the wall charger, the green light starts blinking. I thought it should burn solid green, right?

A: It should, and a blinking light means there is a problem. It could be the lipo is bad, be sure to check the voltage with a voltmeter. If the voltage is good (at least above 3.0V, preferably higher) you might have a little contamination on either the battery contact strips, or the charger's strips. Clean the battery first, if the problem stays, clean the charger's contacts as well.

Trim Issues:

Q 1: The swash plate is not level. I think this asks for some major adjustments...

A: Don't level the swash! The weight distribution on this heli requires the swash to be tilted backwards a little to hold steady. Same applies to the sideways tilt, but this is because the heli hangs slanted in the air, like we discussed earlier. Just trim it in the air, not on the ground, this is not a CP heli. On the Bravo SX the swash is tilted less, because the center of gravity (CoG) is more to the back on this heli. Still, the same principle applies, if you level the swash, you'll end up trimming the heli back to the original swash position with the TX to get hands free stable hover ability back.

Q 2: I need almost maximum trim to hold the tail straight. Or the tail is very "twitchy/shaky". This can't be good, right?

A: This can be a sign your tail motor is (going) bad, especially if you have to move the trim a lot to the right, but it can also be that the tail rotor is not fully okay, or your base setting for the rudder stick is way off. If replacing the tail rotor won't help, you can adjust the base setting for rudder trim. With the TX in mode 2, power up TX and heli, then press the little button on the back of the TX a few times in quick succession. The button is located near where the antenna is mounted. You will hear a beep and notice all trims are set to neutral. Now you can fly like usual (except the rudder stick will do nothing!) and make trim adjustments, but you won't see the trim indicators moving. Adjust the tail trim until it is holding well, and land the heli. Press the little button on the back one more time to hear an affirmative beep the new setting is locked in. Now trims will move again, but since the tail is holding with the new setting, you have equal “trimming space” to both sides again. You may also notice the tail responds better in both directions.

If this won't work, it might be that the flight battery is fading in performance. Draining it too far by pushing flight times is the most common cause for this. The lipo will loose it's capability to maintain a decent voltage under load, and the tail hold is the first to suffer from this. In this case, try a known good or preferably new flight battery, this might make a big difference.

Important: On some Bravo SX units the subtrim for the tail motor won't work. This is a manufacturing defect/bug, presumably only present on early produced helis, when the RX-01 receiver first appeared. Currently there is no fix for this, except replacing the receiver board.

Q 3: I need almost maximum trim for elevator/aileron to keep steady hands free hover.

A: In this case you have 2 options. You can use the sub trim method, like with the tail motor, or adjust mechanically. This means carefully snapping off the links between swash plate and servos, and turning the plastic connector a turn, before snapping it back on. This is especially recommended if the trimming makes the servo be very far away from centre with the sticks neutral.

How to enter subtrim mode was already mentioned in the question above this one, where we were fixing tail trim problems. The procedure to subtrim the elevator and aileron servo is identical, except you press different trim buttons, the same ones you would use when trimming in normal mode.

There is also an adjustment for the gyro in subtrim mode. Pressing the throttle trim up increases gyro, pressing it down decreases it. I haven't used it myself because most tail issues are tail motor or tail rotor related anyway, or caused by fading batteries. But you will get much better piro-rate with reducing the gyro to zero, and then about 6 clicks up again. Look at the video directly below for the amazing results. The tail might become a little more twitchy, but I heard from others it still handles well outside.

Still, as there is no way that I know of to reset gyro to factory default (although some reported the gyro is set to max on default), it might be wise to use this adjustment with caution.

Q 4: I adjusted the servo links, but trim became worse, and I forgot to measure them so I can't go back to the old length. What is the stock length for the servo arms?

A: There isn't really a stock length, the optimum length varies among helis. Amount of play in the swash, neutral position of the servos, trims and other small differences can affect this. But to have a reference for those that need it, I measured some linkages and got these results. Length is taken from the z-shaped part of the metal rod to the center of the hole in the link that snaps on to the swash arms.

Elevator: 28 mm
Aileron: 25 mm

Q 5: My servo(s) lock up when steering full movement with the stick. If I move the stick less, it works okay. What can I do?

A: Sometimes a little trimming, and adjusting the link between servo and swash to compensate the difference might work. But otherwise, EPA or End Point Adjust is what you need. This is a hidden mode in the transmitter, that needs a special procedure to access it. As I recall Himalaya was the first to provide this information, and here is how you do it:

**** EPA, or End Point Adj. ****

▲ enter Sub Trim Mode
▲ unplug the lipo of your bird and plug it back in to enter EPA adj.

△ to set Aileron left end point, push&hold right stick to max. left positon, press T4 to adjust, right = less throw, left = more throw.
△ to set Aileron right end point, push&hold right stick to max. right position, press T3 to adjust, up = more throw, down = less throw.
△ to set Elevator forward end point, push&hold right stick to max. forward position, press T1 to adjust, right = less throw, left = more throw.
△ to set Elevator backward end point, push&hold right stick to max. backward position, press T2 to adjust, up = more throw, down = less throw.
▲ press the back button to save&exit when done.

I would recommend to carefully watch the servos move when you do this EPA trim. Stop moving when the servo sliding block is 1mm apart to the hardware limit. Hitting the hardware limit will cause the servo lock up, you may have to manually spin the tiny servo gear to rescue it from the lock-up. The next picture explains what T1~T4 here all stand for. It's the four trims in futaba order, T1~T4 from right to left.

For completeness, this is the link the the original posting which contained this information:

Q 6: Why are there 3 trim buttons for every stick? What do the top ones do?

A: These have no function, that is, until you decide to switch the TX from mode 2 to mode 1. This TX can be switched between modes by simply mounting the antenna 180 degrees turned. Then you turn the whole TX upside down, so the relocated antenna faces up again, and the 2 previously unused top trim buttons have now suddenly become the 2 bottom trim buttons, and control aileron and rudder trim. This means you can still trim those functions with your thumbs easily. I don't think there is a single TX out there that makes switching between modes so easy.

Q 7: Some of the controls don't work. Like throttle stays at 100% even with the stick down. Or a servo will only move one way. Do I need a new receiver?

A: First thing to try is stick calibration. This mode is also covered under "other problems", in the posting just below this one. Press down both sticks, so you hear the swithes beneath the sticks click, and hold it there for a few seconds. 3 dotted lines appear on the display, then press down on the sticks and rotate them a few times through all positions, to calibrate sticks' ranges and return the TX to normal operation, hopefully restoring the controls.

If this won't work, or you want to analyze a problem more thoroughly, there is a way to determine if the problem is receiver based, or TX based, by using the simple mode changing feature. Remember, when in mode 2, throttle will be on left vertical stick, and rudder on left horizontal. Right stick vertical is elevator, and right stick horizontal is aileron. In mode 1 this changes to left stick vertical = elevator, left stick horizontal = rudder, and right stick vertical = throttle, and right stick horizontal = aileron. So when you change the TX from mode 2 to mode 1, and the left stick becomes the right one, because you have to turn the TX upside down, some controls are physically changed from one stick to the other. We can use this to diagnose a control problem.

Let's consider some examples to make this more clear. Let's say the elevator servo goes to full forward position, regardless of stick position. When changing the TX to mode 1, elevator physically stays on the same stick, but since the TX was turned upside down, up and down for elevator are also reversed. So if the stick was constantly steering full elevator down in the mode 2 situation, when in mode 1, it should move full up, if the problem is caused by the TX. If it still moves down aka forward, the problem lies in the receiver.

Another example, say the aileron servo steers full right, regardless of stick position. We change the TX to mode 1, and now aileron is controlled by the other stick. If the problem was TX based, we should now have a rudder problem, and the aileron servo would behave normal again. If not, the receiver is the cause.

Q 8: The main motor is not working? What can be wrong?

A: While there is always a chance the main motor itself is broken, there are 2 things to check first, before ordering parts. First, the throttle trim needs to be set at neutral. Second, the motor's connector should be firmly in place on the receiver board. Vibrations or crashes might nudge the connector off.

Q 9: Suddenly my rudder is not working, but all other controls are fine. Help!

A: Pretty good chance your transmitter is still in subtrim mode (see Q 2 and Q 3 for more details about this mode). The solution is simple, press the little button on the back of the TX a couple of times untill you hear a beep, and everything should be back to normal again.


Generally this is a very maintenance free heli. Parts are small, and so are the forces acting upon them. Lubrication is not really needed, and in most cases might even casue dirt to stick to parts, causing malfunction or excessive wear. There are a few things to observe though, on a regular basis.

- Most important!: The metal contact strips on the battery can get smudgy from fingers and other things, symptoms are intermittent contact when the battery is inserted in the heli or charger, or even sudden power loss during flight, causing the heli to crash. Other side effects might be a messed up servo settings, causing a servo to behave erratically. If the metal looks dull, use a cotton swab with a drop of cleaning alcohol on it to make them shine again, and have better electrical contact. If cleaning with a cotton swab won't restore contact, take a small piece of waterproof sanding paper, grain 400 or so, fold it, and use the edge of the fold to slighly sand off any corroded metal. Also check the contacts on the heli, sometimes these need to be bent a little to make better contact with the battery.

- Check if the servo gears are clean. A small speck of sand can cause the servo to jam, and even damage the receiver board.

- Check if the tail boom is still fully pressed in. Sometimes the fit is a bit loose, and it can work it's way out slowly. If it is very loose, use a small drop of CA glue to secure it. That way it can still come loose when you have to replace the tail set

- Check the motor connectors on the board. Vibrations can make them come loose, and cause intermittent contact

- Check all moving parts in the head and the tail motor for foreign objects, like hairs etc.

Other Problems

Q 1: My TX has locked up in bind mode. I see three lines but they are not moving and I hear no beeps...

A: This is actually a hidden stick calibration mode. It can be accessed, sometimes by accident, by pushing down both sticks (there is a little switch beneath every stick) and holding them down for a few seconds. Getting out of this mode is simple, some like Marconos posted a solution a while ago, but some info was lost in the translation. What you do is press down on the sticks, then rotate both sticks simultaneously through their full range a few times, and the display will come back to normal.

Here is a video that shows how the TX can get locked in this mode, and be restored to normal operation easily:

sbloccaggio radio nine eagles (2 min 7 sec)

Q 2: How do I bind the heli to the transmitter? My manual is in Chinese...

A: In this case the manual of the Proto Max offers support. This is the correct procedure:

Turn on the transmitter. Lower the throttle control stick all the way down. Adjust the throttle trim tab until the throttle trim indicator is centered and the throttle position indicator reads “000.” Turn off the transmitter.
Connect the LiPo battery to the helicopter. Turn on the transmitter while pressing inward on the throttle control stick until the blinking blue light in the helicopter remains steady, indicating that the receiver is reading signals from the transmitter—this should happen within a few seconds.
If it doesn’t work the first time, disconnect the LiPo battery from the helicopter and turn off the transmitter. Repeat the binding procedure again by reconnecting the LiPo battery and turning on the transmitter with the throttle stick depressed. The receiver is now “bound” to the transmitter and the helicopter is ready to fly.

Upgrades and other Mods

Q 1: Do I need the Xtreme upgrades for this heli?

A: Well, in short, you don't need any upgrades, but some of these certainly have some benefits. Metal parts are usually more wear resistant than their plastic versions, and can be stronger, like for instance there is no more shearing of blade pivots when crashing with blades spinning when using the metal head. Some will like the shiny appearance of metal. There are also drawbacks. Metal parts are not cheap, and are also heavier, reducing flight times a little. Every one should decide for himself if the benefits outweigh the drawbacks. Some are very happy with it, and will never go back to stock setup, while some others prefer the heli in stock form.

Most that tried it like the Metal Swash. It reduces lateral play because it has a ball with hole in it in the center of the swash, acting as a bearing. It also has metal arms, so no more balls snapping of when removing the steering links coming from the servos. I got the impression the cyclic response was a little faster, and more crisp, but not really dramatically. Anyway, a fine piece of work, and worth considering

The CF Flybar is nice, it offers choice of flybar weights, to adjust response to the pilot's preferences, and is more rigid than the stock one. It's also a little shorter, so it can't strike the tail or canopy during wild moves. If may be a little more fragile though, but it offers a nice option to tune your heli, with the different weight options.

One word of caution though. When flying fast outside some reported the heli was more susceptible to "death spiral", meaning the heli will start a wide left circle, moving sideways and backward, and eventually crashing. Another issue is that the balls on the flybar, where the linkages are fitted, are a fraction too big, so the linkages will be hard to snap on and bind when you do get them on. A little sanding to make these slightly smaller solves this. Xtreme has promised this will be solved in later batches. Some also reported the thread in the weights is not cut very precisely, so it may be tricky to secure the weights.

Replacement Skids have also been added, made from delrin, these are really durable, and at a slight extra weight penalty. For those that keep breaking the stock skids (although some stock skids are also almost indestructible, might depend on what batch they came from), a must have, I think. These do add a little weight, being around 0.9 g heavier than the stock skids, which are only 1.38 g.

The Metal Head offers some benefits, we already discussed how it will prevent sheared off blade pivots, since the feathering shaft is now solid metal. The added weight over a stock head (weighing 0.36 grams) is quite substantial, as the metal head is 1.53 grams. But now a Delrin (plastic) version of the metal head has been released, which is around 0.4 grams lighter than the full metal version. The feathering shaft is still solid steel though, so for those that want to save more weight, it would be wise to replace the feathering shaft by CF or hollow aluminium for instance.

The replacement Main Gear seems to have little benefits. It has small cooling fins instead of normal flat spokes between center part and the outer section. While these might supply some extra airflow over the motor and added cooling, it also makes the gear noisier than stock.

The new Main Blades look great, with nice differently printed graphics, and these have winglets, so reduce drag and tip stalling. The center section has a very smooth profile, which makes the blades look very sleek and might reduce drag even more. Drawback is that there is little "flesh" for the screws to fit in, and the blades tend to be a little too flexible.

Xtreme is also working on more upgrade parts, including a new tail blade, and perhaps some more parts. For the most recent information, check this topic:

Q 3: Is there a way to get more performance?

A: If you already tried better batteries than the weaker stock cells that the Solo Pro comes with, there are other options. Some people have been working on a brushless setup, and although this adds a lot of extra power, it also adds weight, and requires a much stronger tail. The tailboom also needs to be lengthened to counter the main motor's extra torque. The flight character of the heli changes a lot because of that, and not everyone may like this.

There is an easier way though, the Bravo SX main motor is substantially more powerful than the Solo Pro main motor, and is a straight drop-in replacement for the Solo Pro. If you don't mash the throttle all the time, the tail can stay the same, it will hold well enough. Or you could fit a Bravo Sx tail set, which has an upgraded tail motor. Make sure you cut the tail to stock SP tail length when fitting a Bravo SX tail. A longer tail will make rudder turns less fluid, the extra few mm length it has over the stock SP tail is only needed on the Bravo SX, the Solo Pro works best with it's normal length tail.

Q 4: Do the motors need heatsinks?

A: Small, high speed coreless motors, like used on the Solo Pro, can get hot after continuous operation. Most tend to limit flight times to about 6 minutes (one battery) and then let the heli cool for 5 minutes or more. If you do want to fly batteries back to back, this heatsink mod, Marconos came up with, might help:

dissipatore di calore.wmv (2 min 26 sec)

Just remember that a coreless motor can be much hotter inside, where the windings and the brushes are, than on the outside. It is not sure if a heatsink will help to keep motors cool enough after long flights, but it will certainly help some.

Q 5: Can I replace the sticks on the TX to get more control?

A: Not directly, the sticks are not seperate parts that can be unscrewed or so. But you can still make them longer to have more control. You can use bamboo skewers, sanded to fit the hollow sticks, to get more "feel" on the controls. Recenty, someone reported the top section of the sticks is just loosely glued on, so with a little force, can be removed to replace with bigger sticks. Not sure if this mod is totally safe and fully reversible.

More info can be found in this post:

Q6: Can I use the Solo Pro TX to control a Flight Simulator?

A: Well, not straight away, but with some clever modding, it is possible. For more details with the oval shaped TX, check this topic:

This topic shows how to use the J6Pro instead:

Q7: Can I fit the Bravo SX canopy to a Solo Pro?

A: Not straight away, as the mounting pins are on different places on the Bravo SX frame. Canopies of the Nine Eagles coaxials are a direct fit though, except the Bravo III canopy, as it is almost identical to the Bravo SX canopy. If you want to pursue fitting the Bravo canopy, also consider upgrading the main motor to a Bravo SX one, as it's heavier than the stock Solo Pro canopy. This video shows how to fit the canopy:
Solo Pro with Bravo Fuselage.wmv (4 min 28 sec)


"Master Tinkerer" EQMOD also did some amazing mods to his Solo Pro, changing head setup and more. I won't go into detail much, since I haven't tried any of those, and can't comment on how difficult they may be to apply. But I would like to point to the topic where EQMOD gathered his mods, so those that like some adventure, can see how this heli can be improved even more:
Last edited by SoloProFan; Mar 01, 2016 at 01:48 PM.
Nov 11, 2010, 04:25 PM
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FAQ part #3 - Solo Pro 270

Solo Pro 270 specific section

The latest addition in the 100-size Solo Pro 45 degree flybar FP family, the Solo Pro 270, is also a very nice heli, so it will get some seperate attention here:

Main features/differences compared to Solo Pro V and Bravo SX:

- Flybar located below rotorblades, and unable to strike canopy or tail boom during flight
- Thicker CF tail boom, and tail motor mounted a little higher
- Main shaft now has dampened feathering shaft, so no more breaking off those small blade pivots
- Swash has center ball hub, to reduce lateral play, and swash anti rotation pin now pointing straight backward, instead of 45 degrees
- Slighty different receiver, and different transmitter (J4Pro), might be able to bind to Futaba TX (still unconfirmed)
- Slightly differently shaped tail rotor
- Differently shaped main blades

These changes make this heli very pleasant to fly. It's very smooth in it's control response, has a good tail hold, and it's more quiet than the Bravo SX, and even more silent than the V-series. Hover, once the heli is trimmed out, is very stable, almost like a Syma S107. I haven't seen a 45 degree flybar FP heli hover this solid yet. It's also less affected by ground effect, as you hover close to the ground, making take offs and spot landings much easier.

As this heli uses a very similar design of key components, many problems can be adressed by following the FAQ content in the first 2 postings. So for now I'll only discuss some 270 related issues here.

First Impressions:

Q1: My servo's are often buzzing a little, like they are searching for their positions. Is that normal?

A: Initially all 270 receivers had this, so it's a little hard to call it a malfunction. Perhaps they tried to increase the servo's resolution, but it appears to be pretty harmless, and doesn't appear to affect control response once in the air. Later batches of the receivers appear to not have this buzzing "issue".

Q2: This heli doesn't have the "take off help mix" the 260 and SX have. Was my board badly programmed?

A: There is nothing wrong with your board. Since this heli remains very stable when close to the ground, it's not really needed, and that is probably why it was removed. For a perfect vertical take off you would need to apply a slight touch of left aileron while increasing throttle, but even without the 270 will likely have a neater take off than the 260, with the mix.

Q3: Can I use my Solo Pro/Bravo SX TX to control the 270?

A: No, this is not possible. The 270 receiver might look like a simple revision of the 260 receiver, but these are not compatible. It appears though that this heli, or a later batch of the 270, is to be compatible with Futaba transmitters. Details about this are still sketchy though.

The transmitter that comes with the Solo Pro 328 however, can be bound to the 270. Also, the J6Pro can be bound to the 270, but only when "Communication Protocol R-0" is selected. On page 27 of the J6 manual is a section on changing the Communication Protocol choice. You will need to set it to R-0 for the SP 270 (which actually looks like A-0 on the display). Then just bind normally (see P26 of the same manual).

Flight Issues:

Q1: I've flown outside, but the heli seems to struggle more to pick up speed. What is wrong?

A: For some reason the servo throw on the 270's receiver is greatly reduced compared to the Bravo SX and 260 aka Solo Pro V. It's like flying on low rates on the 260. Perhaps this was intended to avoid the servos locking up at the endpoints under any circumstances, but it also limits the heli's potential. So far it seems to be impossible to alter the servo travel with the stock J4Pro TX, and the only way to get full throws is to change the receiver for the 260's one, which has adjustable endpoints on the TX. As both receivers are identical in board shape, and the mounting holes are also the same, this swap is straightforward.

It seems on recent batches (we're talking second half of march, 2012) throw is more on par with the 260, and there is no direct need for fitting a 260 receiver to get faster forward flight.


General remark, except for the head components, this heli is built the same way as the 260 aka Solo Pro V.

Q1: How do I replace the flybar?

A: The procedure is fairly identical to the Solo Pro, except the pin is not press fit into the flybar, using the shaft as pivot point, but the other way around. So if the flybar can't pivot freely (testing with links not attached) the holes in the flybar might need reaming, and not the hole in the shaft. Best is to unsnap the long links at the mixer arms, then remove the screw that holds the head on the main shaft, and pull the head off. Slide the guide piece off the rest of the head, then unsnap the links between mixer arms and flybar. Finally, slide out the pin, and the flybar is free.

Q2: Can I repair a broken flybar?

A: When making a crash with the blades still spinning (also called "under power") there is a risk that the flybar breaks just outside the balls, where the links to the mixer arms are attached. It's possible to repair this with nail glue (perhaps a decent CA glue will work as well) and a tea bag. First glue the 2 halves together with the glue. Then carefully wrap small strings cut from the tea bag around the broken area, acting as a splint. Soak the tea bag strings with CA, and let it cure. Should be as good as new. You might create a slight unbalance in the flybar, in that case, add some weight on the other side as well, perhaps adding a "splint" on the opposite side, just to prevent future breakage there.

Trim Issues:

Q1: Does this heli still have subtrim, like the 260 and 320?

A: At first this option didn't appear present, as the TX of the 270 lacks the button on the back, that is used on other helis to access subtrim mode. But it's still there, it just needs a little different procedure to access it. Push down on the right stick, the one you use to switch between low and high rates, hold it down, and then push down the left stick 3 times. That will put the TX in subtrim mode. Unlike on the 260 and 320, in subtrim all controls still work, even the rudder. So it's possible to fly normally in subtrim mode. When finished trimming, one click on the left stick will put the TX back in normal mode.

Power Options:

Q1: What batteries can be used for this heli?

A: The stock battery is the BA-927, which is the same battery the Bravo SX uses. In contrary to most stock batteries, this one has already proven itself in the "power hungry" Bravo SX, as a battery that gives good power, good flight duration, and also good life expectancy. Typical flight times on this 150 mAh battery are around 6 minutes.

The Hobby King OEM 150 (BA-925) can also be used, but performance is less, with a possibly less strict tail hold, and shorter flight times, despite being also rated as 150 mAh. The NanoTech 160 is now also sold fitted with a NE style connector, so these are an option as well. Performance is better than the BA-925, but the NT 160 is also about 0.5 gram heavier than the stock Nine Eagles BA-927 batteries, putting a little more strain on the motors, and possibly reducing climbout power. Personally I prefer the 927, but if money is tight, the NT160 is a viable replacement.

When converting the battery holder to accept mSR style plug batteries, the 160 mAh versions of batteries like Thunder Power and other brands, are probably what to go for. Lower capacities will limit flight times noticably, and may not even be able to deliver the current this heli needs for good control response.

Upgrades and mods:

Since this heli is pretty new, no real upgrades have been produced yet. The swash already has a center ball, and the head has rubber damper rings, like the Xtreme heads for the 260 and 320. User Bobepine reported that replacing the rubber dampers with those for the Blade mSR has made control response slightly more direct, as the stock rings apparently are softer.

Apart from that the only performance increasing mod so far is swapping the board for that of the 260, so you get more servo throw, and the option to adjust the gyro setting, thus influencing the piro-rate, like on the 260 and 320. When flying outside, this board swap is very recommended.

For those that want a different canopy, there is some good news. User Bobepine also tried the MIA canopy kit on the 270. His comments: "As you can see, I did not need to use the upper part of the boom mount. No need on the SP270. In fact, there is no modifications required at all. It's plug and play. No need to install a canopy mount, it fits right onto the stock canopy mount. Also no need to modify the tail boom mount, either, like using part of another frame to make this work. Things line up perfectly with the stock tail boom mount. It's like this mod was made specifically for this heli. Very cool."

The overall result is indeed nice:

Last edited by SoloProFan; Sep 23, 2012 at 03:30 PM. Reason: Added SP 270 specific content
Nov 11, 2010, 04:31 PM
staff tecnico-prismalia-techn
marconos's Avatar


not to underestimate the heat,
There are four degrees of difference between the model with heat sink ............
ideal because it is made with aluminum foil tape with a few grams of weight.

dissipatore di calore.wmv (2 min 26 sec)
Nov 12, 2010, 12:07 AM
Fan of just about anything RC
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Thanks for mentioning this. And added to the FAQ, along with some tips about the TX batteries.

FAQ became sticky, thanks moderators!

Updated section about spare parts, mentioning option to use parts from other helis/brands

Originally Posted by guy1a View Post
very good !

Originally Posted by marconos View Post
I complimeto for the initiative, why resize everything that belongs to the only pro
In this case we start from nothing more than a step away anything to the old post .............
a trend I hope it is useful to all,
with great effort that our dear friend-PRO-SOLO
make available to the community forum ...........
with remedial action and interest .............. thanks.

I would like also to point out that in my country there are people who
copy your ideas, and show boasting that holy men,
but I always follow that you understand that this is not correct,
reason that I almost abandoned the forum in my country,
I need people to stimulate new initiatives, not to copy others' ideas ........
thanks to you all .....................

Thanks for the compliments. I will try to add credits to posted information when due, if I forget that sometimes, just contact me, and I will correct that. This is meant purely to be a source of information, not trying to show off or try to appear to have more expertise on any matter.
Last edited by SoloProFan; Mar 01, 2016 at 01:47 PM.
Nov 12, 2010, 12:56 PM
FPV! and nothing else matters.
guy1a's Avatar
tips about batteries and wall power adapter.

added adapter for the turnigy batteries.
Nov 12, 2010, 01:30 PM
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Originally Posted by guy1a View Post
tips about batteries and wall power adapter.

added adapter for the turnigy batteries.
Personally I am backing off a little of using batteries with eflite connector, since there can be some issues with this plug, and have been converting more of these batteries to a NE connector, but for completeness I will list this method of charging as well. Really like how this way of using the NE charger doesn't require modding of the charger itself, but just uses an old battery's connector.

Did you invent this or did you find it? So I know who to credit for the idea.
Nov 12, 2010, 04:37 PM
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Added the part about modding the charger, and TX lock up or stick losing function...
Nov 13, 2010, 12:25 AM
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Originally Posted by guy1a View Post
i did it, i am not sure if i am the first .. it may have been done before ... though i didn't find it one the web.

i don't need the credit

my reward is the future generation can use the data.
That's the spirit, and what this thread is all about.
Nov 14, 2010, 07:53 AM
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Added some info about the Xtreme Metal Head and updated the part about the different versions.
Nov 14, 2010, 04:48 PM
Registered User
i am a newbie from greece.
read this thread and really think it's helpfull, especially the TX settings stuff you posted.
i have a little hack i have to offer: making a hole to a broken rotor head and putting a little metal rod instead of the little rods that keep breaking solves the rotor head problem for good.
Here'w how you do it:
1. take a broken rotor head and make a hole in the exact place where the little rods where, about 1mm wide.
2. take a big paper clip and cut a piece about 1cm. put it through the hole and cut to fit with the blades on.
3. cover the protruding bits with small pieces of electrical tape.
youre done!

here's a picture of it finished, only the right side is covered with electrical tape.

i did this quite a while ago, and it works great, but i don't have step by step pictures or videos.
if it brakes and i have to do it again i will post a video.
Nov 15, 2010, 01:02 AM
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Thanks for the contribution and the compliments about the thread. I did indeed not list this mod/repair yet, but knew of it's existance. There are more variations, like using a straw from a spray can or even a tooth pick. I will soon add this info and maybe use your picture, although I think I have seen some step by step pictures or a video, so I might use that as example picture instead.
Nov 15, 2010, 08:02 AM
Registered User
Here's another pic
Nov 15, 2010, 08:55 AM
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Originally Posted by Helicrush View Post

Since you know this bird well, could you post the lengths of the AIEL and ELEV servo arms for the Solo Pro II, for "normal" flying? Lenght from ball hole to where the metal bends into the servo arm hole...or whatever you choice. One of my Solos is out of whack, and it would be good to have a "default" value to start from.
"Normal" depends on your trim settings on the TX and programmed endpoints on the receiver, plus the variations in swash plate (some are more tightly pressed together than others) to name a few things. So I can measure my servo arms, no problem, but the lengths may not at all be right for your heli. What I usually do when a heli is way out of trim, is trim the tail on a flat surface, just throttle up till the heli will still stay on the ground, but get a little "light" on the skids.

Then do a handlaunch, holding heli with right hand, go to about 50% throttle or whatever percentage needed to make the heli want to "escape" from your hand, and take the TX. See what stick movements you need to keep the heli steady, and trim asap. If your trims don't provide enough "room" use subtrims while on the ground first.

But if you really want to make the arms "my length" first, no problem, I'll measure them when I get home.

@Borjo: can you make a pic with the head right side facing up, and sharp? Now the bottle on the side of the picture is really sharp, but the head itself is a little blurry...
Nov 15, 2010, 10:26 AM
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Originally Posted by Helicrush View Post
Thanks, I managed to get a better flyer by adjusting the ELEV servoarm a little down, then used the subtrim reset procedure.
Ok, glad to hear. I will add a part about servo arm length to the FAQ, just in case...

Edit: Added the part about how to repair the main shaft, and "stock" lengths for the servo arms.
Last edited by SoloProFan; Nov 15, 2010 at 01:22 PM.

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