HobbyKing.com New Products Flash Sale
Reply
Thread Tools
Old Oct 10, 2011, 02:46 PM
Right Rudder
PittSpecial's Avatar
USA, FL, Orlando
Joined Nov 2010
8,988 Posts
Quote:
Originally Posted by mikepapa View Post
Have you ever run the Sensei at about 1/2 throttle using your briefcase setup and let the system run until the battery is discharged to 9v? How long did it run? Did you notice any overheating? I did this and my motor smoked. I am trying to decide if the Sensei needs more airflow when not in the air.

Thanks,
Mike
Mike,

The Video was exactly what you saw...just a few seconds of static testing and that is IT!

I do not prolong any Static testing on the ground.

Carlos
PittSpecial is offline Find More Posts by PittSpecial
RCG Plus Member
Sign up now
to remove ads between posts
Old Oct 10, 2011, 02:51 PM
Registered User
Joined Jul 2011
116 Posts
I mistyped. Meant to say 3.85 volts for each cell.

I went back out today and it occurred on every flight. We've pretty well decided that it is electrical. I'm not the best solderer in the world and I am going to redo my solder joints on the battery pigtail plugin on the plane just to make sure I didn't get a cold solder joint. And see if that fixes it.
proweddingphotos is offline Find More Posts by proweddingphotos
Last edited by proweddingphotos; Oct 10, 2011 at 03:14 PM.
Reply With Quote
Old Oct 10, 2011, 02:52 PM
Right Rudder
PittSpecial's Avatar
USA, FL, Orlando
Joined Nov 2010
8,988 Posts
Quote:
Originally Posted by proweddingphotos View Post
I'm using my Spectrum DX6i with a full range Spectrum sports receiver. 3c 2200mAH Li-po batteries.

So, could I be experiencing a soft low voltage cut off that keeps me from climbing out from time to time? Although the batteries usually show 40% or so left in them when I take them out of the plane after the flight (I check them as soon as they go on my charger to see what he mAh reading is?)

What is the soft cut off voltage, does anyone know? I've got this meter I plug into the balancing wires of the battery when I take the battery out of the plane after a flight and each cell usually reads about 1.85 volts at that time.

I'm usually at half throttle on a low level flyby when this (no increase in power to be able to pull up to go around again) happens to me.
I do not understand what you are talking about with respect to 1.85Volts?

My typical flight operation is getting a Turnigy 3-Cell, 2200mAH, 25C discharge, Li-POLY and its off-the-charger Voltage reads: 12.54 Volts "or" 4,18 Volts each cell. After perhaps 9 minutes of "Mix" throttle I land my SENSEI to have the Battery pack reading 11.86 Volts "or" 3.95 Volts each cell.

I highly recommend that you seek knowledgeable assistance from a local hobby shop that they can do an evaluation of your Power System as these threads do not provide good method.

I am just taken-a-back from your reference of 1.86 Volts each cell...

Please take your model to a Hobby Shop so, they can determine if all is okay with your power system.

Carlos
PittSpecial is offline Find More Posts by PittSpecial
RCG Plus Member
Old Oct 11, 2011, 12:14 PM
Registered User
Joined Jan 2009
10 Posts
Sensei Upgrade/Conversion to RimFire .10

Quote:
Originally Posted by PittSpecial View Post
Mike,

The Video was exactly what you saw...just a few seconds of static testing and that is IT!

I do not prolong any Static testing on the ground.

Carlos
Ah the light is dawning. The fellows at the LHS also said it is suicidal to do a full battery run of a motor/esc on the bench. This is probably the cause of my motor frying. The ESC frying is another story as this occurred in the air.

Posted below are pictures of the conversion I did to put a RimFire .10 motor and 50A Castle Creations Phoenix ICE ESC into the Sensei. Note that aside from making the center hole and 2 mounting holes on the motor mount a little bit bigger, no mods were made to the Sensei Cowl other than re-gluing with Gorillia foam glue after 2 hobby knife surgeries. This power setup pulls about 30% more watts than the stock motor. I have not flown it yet but it should be fine. The motor/esc replacement required NO change in weight for proper COG.
mikepapa is offline Find More Posts by mikepapa
Reply With Quote
Old Oct 11, 2011, 04:09 PM
\_(ツ)_/
Joined Sep 2011
738 Posts
Fried again!

So, the motor fried again. For anyone who has not been following, this is the second motor/esc to fry on me, the first was 2 days old and was replaced by the company. This one has faired much better. I actually got a good 10 flights out of this one.

Today I went out and flew 2 flights, (2 batteries worth), and it went so well I decided to charge them up again and fly later in the afternoon. Maybe 4 hours later, I took my 2 charged batteries and headed out again. I installed the battery, turned on the tx, tested the prop and control surfaces, full throttle, the plane accelerated forward but didn't lift off. Because I was aiming diagonally on the road in order to head as much into the wind as possible, it actually ran right off the road and stopped in the grass. Odd I thought, that it didn't lift off, but whatever I run over and pick up the plane to reposition it on the road, and there is smoke coming out of the motor, right out of the spinner. LOVELY. At first I think MAYBE a piece of grass got caught in the motor and smoked a bit? WISHFUL THINKING! I blip the throttle just to make sure, and all I hear is the noise the prop makes when you first turn on the tx, that beep like noise. No rotation. Shut it off and unplug the battery. Head home, take it all apart and sure enough, the copper twine in the motor is black. Just a couple strands of copper color, that is all.

Here are the pics.









I haven't taken apart the esc to see if there is another soldering problem that could have caused it. I'm taking it back to the local hobby store and they
can take it apart. I'm not going to ask for another warranty swap. I won't put the same thing back in the plane. If they can credit me something, then that's fine. Either way
I'm going to see about putting in a new motor and esc. Something better than this.

As far as I'm concerned, there is enough evidence based on my experiences as well as some others that I've read that there is an inherent flaw with this plane. It's a great flyer, no doubt, and a great value considering the size of the plane, the radio, the battery etc., it's a good package, BUT, there is a defect here for sure. I wouldn't recommend purchasing this exact plane until they figure this out. That's my opinion.
Kawi is offline Find More Posts by Kawi
Last edited by Kawi; Oct 11, 2011 at 04:18 PM.
Reply With Quote
Old Oct 11, 2011, 04:43 PM
Registered User
Joined Jan 2009
10 Posts
Quote:
Originally Posted by Kawi View Post
Because I was aiming diagonally on the road in order to head as much into the wind as possible, it actually ran right off the road and stopped in the grass. Odd I thought, that it didn't lift off, but whatever I run over and pick up the plane to reposition it on the road, and there is smoke coming out of the motor, right out of the spinner.
I wonder if the problem is that the stock ESC on the Sensei has no overload detection or stalled prop detection. If you hit the grass with the throttle up the prop could have stalled and drawn too much current, toasting the windings. Did you see my RimFire .10 conversion? The Castle ICE ESC has built in cutout if voltage is low, prop is stalled, or too much current is flowing. Easy to upgrade as everything just about fits perfectly. The only downside is the motor is about $60 and the ESC $100. Tough medicine to take so soon after buying an RTF plane that was not cheap to begin with. Anyway... good luck with whatever you decide. I second your warning about purchasing a Sensei. By the way, I am heading away from home on a project that will last 3 months. Because I have not flown my Sensei with its new motor, I decided to take it with me! I got a suitcase that is 30" tall, This will accommodate the wings easily. Then I (shudder) chopped the fuse in half just behind the servos. The two halves will fit in the suitcase too. I am bringing some carbon fiber rods to insert into both halves of the fuse when I get to my destination. Add a little Gorilla glue and will be good to go. After all what is a little more surgery on a foam plane? Of course, I will have to reverse the process to get the thing home, but hopefully I will get some flights in. A new fuse from the Mfg is only $60.... this plane is starting to sound like my boat!

Mike
mikepapa is offline Find More Posts by mikepapa
Reply With Quote
Old Oct 11, 2011, 05:02 PM
\_(ツ)_/
Joined Sep 2011
738 Posts
I shut down the motor before I hit the grass, I just didn't have any brakes to stop the plane too. Who really knows what caused it though. Maybe it was still decelerating and still spinning when it hit the grass? Still doesn't make sense.

If I find that it's going to cost me 150 bucks, then I'm going to buy a new plane altogether and shelf the sensei. I've had my eye on the RTF cessna corvailis. It's about 150 bucks RxR, plus it takes the sensei batteries. I just have to see if I can use the tactic radio if I buy a receiver for it.

I'm a bit scared to go to a low wing, but it's a sweet looking plane, has flaps and has lights too lol. Idk, I think I'm good enough at this point to move up a bit, but I am a bit apprehensive at the same time.

LOL it sucks that you had to cut the plane in half, but I guess what are you going to do? It's true you can glue it back together just fine. You might want to use brochette skewer sticks. It was recommended to me and it's what I used to reattach the engine mount. It worked great. They don't snap like toothpicks, at their most bending point, they will splinter and fold. The guys all told me at the shop to not waste money on the cf sticks, the skewers are the best option. One guy said it's what he used to reattach the entire tail of his plane and it's crashed since many times and never came apart. Just something to keep in mind.
Kawi is offline Find More Posts by Kawi
Reply With Quote
Old Oct 11, 2011, 07:34 PM
Registered User
Joined Jan 2009
10 Posts
Quote:
Originally Posted by Kawi View Post
If I find that it's going to cost me 150 bucks, then I'm going to buy a new plane altogether and shelf the sensei. I've had my eye on the RTF cessna corvailis. It's about 150 bucks RxR, plus it takes the sensei batteries. I just have to see if I can use the tactic radio if I buy a receiver for it.
Just check what kind of motor it has first! If you use the receiver from the Sensei then the Tactic radio should work fine. 1 3' CF rod at LHS was $5.00. I used two short pieces to put the cowling back on the first time I removed it. The second time I had to take the cowling off the rods got in the way so I had to saw them through. However, they are hollow so when I put the cowl back on the second time I just glued some piano wire into each end of the hollow rods. By this time I had finally figured out that the cowl actually comes apart into 2 pieces. The motor mount part and the outer cowl which holds the weights. The cowl will never come off now... and I have enough CF rods left over for the fuse halves. I am starting to get angry with having to do any of this.... but....calm.....in the end it is quite an adventure.
mikepapa is offline Find More Posts by mikepapa
Reply With Quote
Old Oct 11, 2011, 07:39 PM
Right Rudder
PittSpecial's Avatar
USA, FL, Orlando
Joined Nov 2010
8,988 Posts
Guys,

I am really amazed of the issues with the motor windings / ESC?

I am very sorry to see it again and most importantly the LET DOWN that one feels after a few good flights and anticipation to fly it again and this happens!

As a matter of fact, early this morning at exactly 8:00am Eastern at my RC Club and on the way to work, my SENSEI took to the sky for two wonderful flights (2 Battery packs). It is certainly faster with the Park Zone 2-Blade, 9.75 X 7.5 propeller and zooms with zest appeal passing us by at the pilots station.

Since we have received two days and two nights worth of rain the field was about 25% flooded and I was able to manage a perfect pin point landing on some construction material that was placed on the field for a make-shift smooth runway run.

My SENSEI has not missed a BEAT!

Oh, my batteries come out ICE cold.
PittSpecial is offline Find More Posts by PittSpecial
RCG Plus Member
Old Oct 11, 2011, 10:22 PM
Right Rudder
PittSpecial's Avatar
USA, FL, Orlando
Joined Nov 2010
8,988 Posts
Quote:
Originally Posted by mikepapa View Post
Ah the light is dawning. The fellows at the LHS also said it is suicidal to do a full battery run of a motor/esc on the bench. This is probably the cause of my motor frying. The ESC frying is another story as this occurred in the air.

Posted below are pictures of the conversion I did to put a RimFire .10 motor and 50A Castle Creations Phoenix ICE ESC into the Sensei. Note that aside from making the center hole and 2 mounting holes on the motor mount a little bit bigger, no mods were made to the Sensei Cowl other than re-gluing with Gorillia foam glue after 2 hobby knife surgeries. This power setup pulls about 30% more watts than the stock motor. I have not flown it yet but it should be fine. The motor/esc replacement required NO change in weight for proper COG.
Mike,

I am so sorry that you bought that RimFire .10

This "is" the same recommended power system that Tower Hobby (Great Planes) issued for the new Super Stearman EP by Great Planes - Electrifly.

The motor is a AMP Hog or in other words it has too high of a Kv (RPM/VOLT and thereby, too low Torque Kt) such that if you attempt to swing that STOCK 10 X 5 propeller with 3-Cell Li-POLYs expect something like 31 AMPS of current draw and lots of heat!!!!

I would caution you with wide open throttle or even 3/4 throttle as you might burn up this motor, puff the battery pack and perhaps ruin the ESC due to heat build up.

For this model, if I was to change out the power system I would seek a motor that does not surpass anything over 950 Kv and at least 28mm - 35mm in diameter.

Becareful...
Carlos
PittSpecial is offline Find More Posts by PittSpecial
RCG Plus Member
Old Oct 11, 2011, 10:57 PM
Registered User
Joined Jan 2009
10 Posts
Quote:
Originally Posted by PittSpecial View Post
Mike,
I am so sorry that you bought that RimFire .10
Well we shall see. The brushless moter configuration wizard on the Electrifly Site called out this motor based on a 3.2lb trainer. The spec was for a 35A ESC. I am using a 50A. The "short" bench test I did showed about 200 watts output at 1/2 throttle. The spec even calls out a 10x7 prop. I certainly will not fly at full throttle! But it is a grand experiment and if it does not work then I will have learned something! I will post my results after my first crash...errr.... flight! Thanks for the heads up though! I have attached the Electrify recommendations... take a look.
mikepapa is offline Find More Posts by mikepapa
Reply With Quote
Old Oct 11, 2011, 11:45 PM
\_(ツ)_/
Joined Sep 2011
738 Posts
Well, i'm back from the lhs and I bought a new motor, an eflite 480 brushless. We examined the esc at the shop, took it all apart and concluded that it did not burn, and that it should still work.
It doesn't. I strung everything together once I got home and the motor receives no signal. So, next I will be going back and getting a new esc. It sucks, but at this point, i'm only that far away from the plane flying again. The new motor is rated at 22 amps, 28 peak. The guy told me the 30 amp esc is fine because those numbers are within that, but from what I'm reading, the esc should be at least twice the rated power, so it looks like even if it did work, it wouldn't last. I have a new prop too, a 10x7. The guy said the 10x5 was underpropped for this motor, and I think he's right, I think it's underpropped for whatever motor was there originally, but I'm wondering if I went to big though, maybe something in between would've been better.

I really hope that I get it right so that I stop going back there. This shop is great and these guys go the extra mile to help me out every time, even though it's not their doing. I really don't want to push things!

Hopefully I end up with a more resilient system. Plus this seems like a good motor to later on transfer onto another plane.
Kawi is offline Find More Posts by Kawi
Last edited by Kawi; Oct 11, 2011 at 11:52 PM.
Reply With Quote
Old Oct 12, 2011, 07:47 AM
Right Rudder
PittSpecial's Avatar
USA, FL, Orlando
Joined Nov 2010
8,988 Posts
Quote:
Originally Posted by mikepapa View Post
Well we shall see. The brushless moter configuration wizard on the Electrifly Site called out this motor based on a 3.2lb trainer. The spec was for a 35A ESC. I am using a 50A. The "short" bench test I did showed about 200 watts output at 1/2 throttle. The spec even calls out a 10x7 prop. I certainly will not fly at full throttle! But it is a grand experiment and if it does not work then I will have learned something! I will post my results after my first crash...errr.... flight! Thanks for the heads up though! I have attached the Electrify recommendations... take a look.
Mike,

Like I am trying to tell you, I assisted a buddy with this power system setup on a smaller and lighter model (Electrifly Super Stearman) and it was just too much Kv, furthermore, there is no motor specifications, motor constants for this motor as I already have investigated several months ago....look for yourself here:

http://www.rcgroups.com/forums/showp...4&postcount=36

The RimFire .10 comes with a very high 1250Kv such that it will be marginal at best to have enough Torque (Kt) to swing a 10 inch diameter propeller with 3-Cell (~ 12.5 Volts) behind the motor.

What I am trying to tell you is that it will work but, most of your electrical energy will be converted into HEAT and not necessarily MECHANICAL energy.

But, who knows, you might like it and like you said, it is an experiment and this model is perfect for such experiments.
PittSpecial is offline Find More Posts by PittSpecial
RCG Plus Member
Old Oct 12, 2011, 07:58 AM
Registered User
Joined Aug 2010
241 Posts
Concerned about the esc/ motor problems on this model. I have about 10 flights on mine with no problem so far. Thought maybe just a few lemons, so I checked the parts availability at Tower Hobbies and Hobby Zone and both stores are out of stock on these parts. Makes me wonder if this is a bigger problem since they have sold out their supply of esc/motors, or whether they had them in stock to begin with. Flyzone site also lists them as out of stock. It would be nice if these companies would identify possible problems on their models, and make corrections if needed. Just wondering out loud.--Bo
bostomper is offline Find More Posts by bostomper
Reply With Quote
Old Oct 12, 2011, 08:48 AM
Right Rudder
PittSpecial's Avatar
USA, FL, Orlando
Joined Nov 2010
8,988 Posts
Quote:
Originally Posted by Kawi View Post
Well, i'm back from the lhs and I bought a new motor, an eflite 480 brushless. We examined the esc at the shop, took it all apart and concluded that it did not burn, and that it should still work.
It doesn't. I strung everything together once I got home and the motor receives no signal. So, next I will be going back and getting a new esc. It sucks, but at this point, i'm only that far away from the plane flying again. The new motor is rated at 22 amps, 28 peak. The guy told me the 30 amp esc is fine because those numbers are within that, but from what I'm reading, the esc should be at least twice the rated power, so it looks like even if it did work, it wouldn't last. I have a new prop too, a 10x7. The guy said the 10x5 was underpropped for this motor, and I think he's right, I think it's underpropped for whatever motor was there originally, but I'm wondering if I went to big though, maybe something in between would've been better.

I really hope that I get it right so that I stop going back there. This shop is great and these guys go the extra mile to help me out every time, even though it's not their doing. I really don't want to push things!

Hopefully I end up with a more resilient system. Plus this seems like a good motor to later on transfer onto another plane.
To keep things light and have a very capable motor, the E-Flite 480 series is the best motor you could have selected, congrats!

From the current rating, I am assuming that it is the 1020Kv form factor of the E-Flite 480.
http://www.e-fliterc.com/Products/De...rodID=EFLM1505

I have this same motor in several models and one specific is the World Models P-51D Mustang EP-40 as shown here:
http://www.rcgroups.com/forums/showt...d+ep+40&page=5
PittSpecial is offline Find More Posts by PittSpecial
RCG Plus Member
Reply


Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
Alert Flyzone Sensei wmcneal Foamies (Kits) 7 Sep 30, 2013 04:00 PM