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Old Mar 04, 2012, 11:53 PM
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Originally Posted by bytemuncher View Post
I think a lot of us are diy'ing the tail boom. You need 2mm cf square tube. It fits but is ever so slightly loose. I think walkera puts a finishing gloss on their stock boom so it fits a bit better.
Oh! The stock Tail Boom is 2mm square CF Beam.

I thought I read indoorheli? posted about using a square boom, but I thought it was an improvement mod because for the same weight of material, square tube is stronger than round tube.

So if I understand your post correctly, the 2 mm square tube is measured from opposite flat sides, not corner to corner? And the square tube fits into a square hole, not round hole?

AFAIK, Mini spare parts just recently became available about a week or so ago (Wow still doesn't have them for advertised for sale, and told me they won't be have them until around mid MAR!). You guy's that have been flying the Mini during the last few months must be really good fliers! I seriously expect to be breaking mine the first day. Hopefully it will be after I attempt to flip it!
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Old Mar 05, 2012, 12:17 AM
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United States, MA, Springfield
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Originally Posted by i812 View Post
So if I understand your post correctly, the 2 mm square tube is measured from opposite flat sides, not corner to corner? And the square tube fits into a square hole, not round hole?
yes it's measured from opposite sides. you can buy a 2mm tube (with 1mm hole) or 2mm rod (solid) and wrap the wires around the boom. square is stronger (stiffer) than round boom and solid boom is stronger than hollow (less chance of splitting).

a round tube will probably fit a square hole but a square rod won't fit a round hole unless you shave the corners off.
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Old Mar 05, 2012, 12:37 AM
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United States, TN, Johnson City
Joined Oct 2011
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Originally Posted by benboy207 View Post
What's the best upgrade battery for this heli? Considering both performance and flight time.

Ben
I think making the conversion to brushless is the best upgrade. It gives longer flight times and better power.
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Old Mar 05, 2012, 12:46 AM
Making Stock Fly Like Modified
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United States, PA, Philadelphia
Joined Oct 2009
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Originally Posted by i812 View Post
I asked Wow why they consider their Mini-"pro" with the Genius Main gear better than a stock Mini with stock Mini Main Gear.

The person I spoke to said the Mini CP with Genius Main Gear runs 200 (rpm?) slower than with stock Mini Main Gear.

I then asked why having a 200 slower headspeed rpm is considered better? I don't remember getting an explanation other than something to the effect of: "it flies better with the slower headspeed", and Wow includes the Mini Main Gear with their "Pro" version, so the owner can compare the differences, and confirm the increase in performance (lower headspeed) the Genius Main Gear provides over Mini Main Gear.

Finally, I asked why Wow didn't choose to keep the thicker, more durable stock Mini Main Gear, and change the rpm by using a smaller Pinion with slightly less teeth count? I heard a soft laugh, a pause, and then he said changing the Main Gear is easier; whereas, changing the Pinion is more difficult and time consuming because of the temperature sensor being attached to the Main Motor.

Afterwards, I went back and re-read a couple of Manny's (buildem336's) posts, and from what I understood, found he prefers slightly lower headspeed on his Mini because he likes to fly it indoors, and thinks slightly lower headspeed causes less damage (to the heli and furniture?) without loss in performance.

I don't know anything about how headspeed effects a heli's flight performance. However, from my limited understanding of Gear Trains, using more teeth on the Main Gear is equivalent to using less teeth on the Pinion. I suppose with the Mini, it is easier and quicker to change headspeed by simply removing and replacing a Main Gear than it is to remove and replace a Pinion? However, unless I planned on changing head speeds often, once I decided on the best headspeed, I'd be more inclined to choose the most cost effective (durable?) long term solution instead of easiest short term solution. If something in the heli's drive-train "has" to break upon impact, then I'd like to intentionally design/use a cheap, easy to identify as defective, and easy to replace weak "link" to function as a sacrificial "Jesus" part. Using Walkera's authorized warranty provider's (HobbyOne's) prices, the drive-train parts cost are:

($9.67) Main Motor
($2.75) Pinion
($4.17) Main Gear
($2.58) Main Shaft
($2.67) Feathering Shaft
($3.33) Blade Grips
($3.33) Main Blades

Main Gear is the second most expensive part, although it may be the easiest to inspect and replace?

Maybe having cheaper but relatively weaker Main Shaft, Blade Grips, Feathering Shaft cost less to purchase, but are more difficult to inspect and replace?
You have it the other way around and actually mean a 200 RPM HeadSpeed gain on this MiniCP Pro that Wow are selling now. It's using the Genius main gear and the upgrade 25C battery it comes with supposedly gives it this extra 200 RPM.

IMO it would be better to buy a stock heli with the more docile headspeed using the stock gearing, and a set of 6.00 training gear for a beginner Cp flyer.

The training gear is one of the most overlooked tools that new pilots dont seem to get with these micros yet its the one thing that will save you the most in crashes in the very beginning. It stops the heli from tipping over and acts like a shock absorber on hard landing and bumping into things.

When you get the mini check to make sure all the electronics work,, connecters are plugged in the correct spots on the RX and tight before power on. If ok then check the motors work, main and tail, servos work and move in sync up down left and right front and back, and RX binds and is auto correcting. If not check all 6 channels in the radio are set correctly from the manual under Reverse section.Then make sure all the screws are tight and tighten up the blade grips if they are too loose. Spool up in your hand and inspect the heli for anything that could be wrong check the main shaft is straight etc..

Once thats done, charge the battery and while its charging set up the radio. Put in 0-85-85-85-85 for a normal mode throttle curve and 50-56-66-76-86 for a pitch curve. For ST1 and ST2 put zeros all across for throttle and pitch so in case you hit ilde up by mistake you dont hit the cieling. Keep Throttle hold a linear curve from 0 to 100 and use that to check your pitch range later.

Set the gyro for ~70-75%, enable throttle hold and set it for -10%, setup dual rates for 70% w/ 40% expo on Aile/Elev and Rudd 100% w/ 30% expo. Make sure subtrim and travel adjust are all at zero.

Next you want to bind the heli up and get the swash close to center of the main shaft, do it by eye for now. Then get 0 degrees pitch, your already there at bottom stick in normal mode if you set the radio up previously, so just fold the blades back parallel to the boom and adjust the 2 long links until both blades are flat and even with no pitch at bottom stick. Spool up and adjust the blade tracking, just pick a master blade...you should see one blade when spooled up, use a small piece of tracking tape on one blade if needed or a dot of white out....... Snap on the training gear, while rechargeing the battery, again.

Battery charged, training gear on and leveled?..... Find a decent sized uncluttered room with carpet on the floor preferable, bind on a flat level surface (important the traing gear is level) and give a slow but steady throttle until the heli hops up a few inches, get a feel for the throttle stick, keep doing it over and over, go forward, back, left and right make sure the heli is acting right. Be quick on the throttle and drop the heli before you hit something.. Eventually, once you get the feel of things and make some radio adjustments, ...... take off and hover a few feet up and take it slow.

In the meantime ;
ask a million more questions, and read a few thousand more threads

Do it this way and I guarentee you wont need any spare parts if you take your time with it. Be methodical and have fun at the same time. its cheaper that way trust me.

Remember if you go with Wow you get 24hours to report a problem and once you fly the heli you own it and any of its possible problems too. That is thier loose policy, which can be strictly enforced. Especially now that you told them your new at CP flying etc........ehh they see you coming. So make sure before you take off the heli is 100 % functional.

Hope this helps you, Its not all inclusive but its a start.
I would have paid someone 50 bucks to give me this info when i first started, it would have probably saved me a thousand in parts and helis and wasted time.. no Shit
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Old Mar 05, 2012, 12:52 AM
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Tokyo
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Originally Posted by itsmillertime View Post
I had a rudder servo burn up when I first connected the RX801 to one of my planes but didn't think much of it. I had the servo bound up several times. Today I replaced the servo and everything worked. Powered it down and tried to fly it a couple hours later and the aileron servo is dead.
So you suspect the rx801 is a servo fryer? I guess they'll stop at nothing to get us to buy their servos.
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Last edited by bytemuncher; Mar 05, 2012 at 12:57 AM.
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Old Mar 05, 2012, 12:57 AM
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Tokyo
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Originally Posted by bobepine View Post
-Servos- I'd get three of them and a bunch of gears if you can get some. And do the servo saver mod out of the box if you want to save $.
I wholeheartedly disagree with this advice. Do the servo saver mod and do not give Walkera another penny for their servos. Okay, if you can find the gears get some...but don't buy the servos.
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Old Mar 05, 2012, 01:15 AM
2 seconds from crashing
indoorheli's Avatar
United States, WA, Seattle
Joined Sep 2007
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Quote:
Originally Posted by i812 View Post
Oh! The stock Tail Boom is 2mm square CF Beam.

I thought I read indoorheli? posted about using a square boom, but I thought it was an improvement mod because for the same weight of material, square tube is stronger than round tube.
!
I might have posted about solid round 2mm tube like my ol mcpx's. When i break my boom I will go solid round because it seems to take quite a bit more bashing than a square tube. To make it fit it needs to have the ends coated same way as the square tube to make it snug
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Old Mar 05, 2012, 01:24 AM
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United States, TN, Memphis
Joined Dec 2011
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Originally Posted by bobepine View Post
This seems to be working fine. The fluctuation in voltage readings actually indicate that there is something wrong with your lipo connection.

I'm sure someone should be able to fix the contacts on the board for you. I know Benmlee is quite experienced. Might be worth offering him a few bucks to fix it for you.

Good luck!
Chris
I calibrated the lcd screen and it fixed the throttle position anomaly. I already soldered new battery leads on my receiver once I realized they were coming loose. I looked over the rx with a magnifying glass but can't see anything wrong. It would bind but when I tried to throttle up to lift off the receiver would fast blink and rebind. After the new leads it did the same thing and now the led won't come on at all.
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Old Mar 05, 2012, 01:25 AM
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Joined Sep 2007
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Try tapping into the back of the rx instead for power
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Old Mar 05, 2012, 01:27 AM
Making Stock Fly Like Modified
HeliFlyer711's Avatar
United States, PA, Philadelphia
Joined Oct 2009
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Quote:
Originally Posted by itsmillertime View Post
I calibrated the lcd screen and it fixed the throttle position anomaly. I already soldered new battery leads on my receiver once I realized they were coming loose. I looked over the rx with a magnifying glass but can't see anything wrong. It would bind but when I tried to throttle up to lift off the receiver would fast blink and rebind. After the new leads it did the same thing and now the led won't come on at all.
You might have a shorted servo, try disconnecting everything fom the RX and just bind with the battery and radio. If it works the RX is ok and the problem is elseware...motors or servos or any of the wireing in between.
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Old Mar 05, 2012, 01:34 AM
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What good would that do? I have the wire going through the board just like stock. I measured the resistance of my new wires and soldering joints and they are at 0. The traces are good because I'm getting power to the capacitor that sits near the battery leads.
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Old Mar 05, 2012, 01:37 AM
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Originally Posted by itsmillertime View Post
What good would that do? I have the wire going through the board just like stock. .
If you have the wire going through the board and getting power to the cap...then nothing
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Old Mar 05, 2012, 03:56 AM
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OnceAFly's Avatar
Singapore, Singapore
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Originally Posted by bytemuncher View Post
So you suspect the rx801 is a servo fryer? I guess they'll stop at nothing to get us to buy their servos.
I have 3 rx801 and all doing fine on my 450's
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Old Mar 05, 2012, 04:03 AM
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Originally Posted by itsmillertime View Post
What good would that do? I have the wire going through the board just like stock. I measured the resistance of my new wires and soldering joints and they are at 0. The traces are good because I'm getting power to the capacitor that sits near the battery leads.
Unless you have a really good (expensive 4 point) Ohm meter, you may not be able to easily measure the difference between a good wire with 7? strands, and a bad wire with 1 strand.

With a "normal" Ohm meter, both the good wire with 7 good strands, and bad wire with only 1 good strand will both appear to measure the same: very low resistance much less than 1 Ohm - down in the "noise".

The reason is due to Ohm's Law:

V (Voltage drop) = I (current through) * R (resistance)

I haven't made current measurements on any Walkeras, but to give you a "ballpark" idea of how the Voltage drops across wires with broken strands, lets use Ohm's Law and see what happens "on paper":

A heli uses the MINimum amount of power and current from a Battery when the Blades aren't spinning. I haven't measured the MIN current, but it is probably less than than 1 Amp current draw, probably closer to 0.1A

A heli draws the MAXimum amount of power and current from a Battery when the Blades are spinning at MAX rpm and pitch. I haven't measured the MAX current, but it is probably approaching 10 Amp current draw. I'm guessing this because the micro helis use 10 Amp ESC's.

I don't know the resistance of a good wire going between the LiPo and RX, but it is very small, something like 0.01 Ohm. My "normal" Ohm Meter measures down to 0.0 Ohm.

I don't know how many strands the wire has, but it is about 7. If 6 of them are broken, the wire's resistance will increase by 7. This means if the good wire with 7 good strands has 0.01 Ohm resistance, then a bad wire with only 1 strand left will have a resistance of 0.07 Ohm. A "normal" Ohm meter isn't going to be able to measure this increased resistance.

But will the heli be able to tell the difference between a good wire with 7 good strands, and a bad wire with only 1 good strand?

Let's use Ohm's Law, to determine what should happen on paper:

The MIN load Voltage drop across a good wire = 1 A * 0.01 Ohm = 0.01V = too small of a Voltage drop to measure

The MIN load Voltage drop across a bad wire = 1 A * 0.07 Ohm = 0.07V = 7 times more than good wire, but still too small of a Voltage drop to measure.

The MAX load Voltage drop across a good wire = 10 A * 0.01 Ohm = 0.1 V = small but measurable

The MAX load Voltage drop across a bad wire = 10 A * 0.07 Ohm = 0.7 V = very measurable = 4.2 V fully charged LiPo appears at RX as if it is 3.5V = time to land!!!!!! (even though the LiPo is fully charged)

I don't know how good my guesses were about the wire resistance and current usage are, but that wasn't the main point of my post. The main point of this post is the Voltage drop going across a wire isn't very noticeable until after a lot of current is going through it, the greater the current going through it, the greater the Voltage drop! The higher the resistance, the greater the Voltage drop.

Bottom line:

Unless all the wire strands are broken, measuring wire resistance with a "normal" Ohm Meter, isn't going to help identify a "weak" wire with broken strands.

Measuring Voltage drop across a wire with a "normal" Volt Meter at MIN load current, isn't going to help identify a "weak" wire with broken strands.

Measuring Voltage drop across a wire with a "normal" Volt Meter at MAX load current, is the most effective way to identify a "weak" wire with broken strands.

(Sorry for the long post, but I hope it helps, because I think many micro Walkera electrical problems are probably caused by bad wires with broken strands, but the wire problem really doesn't show itself until after the Blades are spun up, and approaching MAX current usage - MAX Voltage drop across weak wire(s). IMO, if a person knew which wire, replacing a wire is probably one of the cheapest repairs a person could make. Since I can get scrap wire for free, replacing a wire is a cheaper repair than using CA to fix stuff. I'm guessing many "broken" expensive Motors, ESC's, and LiPo's are trashed because of broken wires!)
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Last edited by i812; Mar 05, 2012 at 04:45 AM.
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Old Mar 05, 2012, 04:37 AM
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Joined Jun 2011
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Originally Posted by bytemuncher View Post
I wholeheartedly disagree with this advice. Do the servo saver mod and do not give Walkera another penny for their servos. Okay, if you can find the gears get some...but don't buy the servos.
I fully understand your gripe about the servos. Heck, I've spent my fair share on servos. In fact, the first few of them I stripped I didn't even know I could reuse the gears or turn the gears to get another round with them. I removed them and threw them out then installed a new one. So far I have purchased more than 10 servos and I only have 3 spares left. This gives you an idea.

Problem is, you need the darn things to fly the heli and if you plan to keep the heli for a while, you will need at least 3 servos to keep going for a little while as not only the gears break. I had 2 of them developing a wobble/jitter and there was nothing wrong with the gears. The electronics in them went bad. YMMV.

i812, you did not answer the question. Is this going to be your first CP heli?

Best,
Chris
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