New flyer getting frustrated

[AndyA]

We built an FT Trainer from a complete FT kit and everything looked good. Went to fly it and it agressively climbed, then stalled and crashed on its nose and broke the prop.

We replaced the prop, connected the battery and the motor started smoking and the ESC caught fire.

Replaced the motor and ESC with versions off Amazon but went with a 1000KV motor instead of the 1250KV the kit came with, thinking it wasn't a significant difference - it was, the plane just wanted to nosedive when taxiing. We checked the COG and it was fine.

Replaced the motor with a 1250KV from Amazon and this time it took off but climbed, veered to the right, dived and crashed on its nose. The ESC immediately caught fire.

Am I right in thinking that the cause of the fires is because the motor is stalled but we were not immediately reducing the throttle, so the motor kept demanding more and more current? Don't the ESCs have current limiting in them to give them some kind of protection?

What make of ESC should I get that does have protection?

The windings on the third motor are short circuited. Is there a make of motor that is more resistant to instant short circuit when crashing?

Right now the motors and ESCs seem really fragile to us.

Thanks! Andy

 

[Mr Man]

First, I’ll answer your esc question: the only esc I’ve ever had that had a high amp draw protection was a Castle Creations 100 amp ICE esc.
I would highly recommend hand launching next time, makes it a lot easier to get it flying quicker. Both flights sound like the planes stalled, causing you to lose all control of the plane. You also mightwant to check control surface directions. On the elevator it should be: to go up, the control surface should also go up, which would be pulling down on the stick. Hope this helps some!

 

[Foamforce]

We built an FT Trainer from a complete FT kit and everything looked good. Went to fly it and it agressively climbed, then stalled and crashed on its nose and broke the prop.

We replaced the prop, connected the battery and the motor started smoking and the ESC caught fire.

Replaced the motor and ESC with versions off Amazon but went with a 1000KV motor instead of the 1250KV the kit came with, thinking it wasn't a significant difference - it was, the plane just wanted to nosedive when taxiing. We checked the COG and it was fine.

Replaced the motor with a 1250KV from Amazon and this time it took off but climbed, veered to the right, dived and crashed on its nose. The ESC immediately caught fire.

Am I right in thinking that the cause of the fires is because the motor is stalled but we were not immediately reducing the throttle, so the motor kept demanding more and more current? Don't the ESCs have current limiting in them to give them some kind of protection?

What make of ESC should I get that does have protection?

The windings on the third motor are short circuited. Is there a make of motor that is more resistant to instant short circuit when crashing?

Right now the motors and ESCs seem really fragile to us.

Thanks! Andy

First, regarding the aggressive climb, first check your elevator trim. Make sure that the elevator is perfectly lined up with the horizontal stabilizer when the radio is turned on and plane is plugged in. Next, check that it balances nicely on the COG marks. I believe the COG marks on the Tiny Trainer are actually a bit too far back, but you can test that first by doing a test glide. Find a grassy area, plug the plane in and turn the TX on. Then, without powering up the motor, give it a medium toss toward some grass. If it’s balanced and trimmed correctly, it should glide nicely, slightly nose down. If the nose comes up and then stalls, then add nose weight until it doesn’t.

Regarding the motor, sorry to hear that. ☹️ Yes, motors and/or ESCs will burn out if they’re locked for more than a couple seconds. This is a really common issue for beginners. Sorry you got bit. It’s rare for an ESC to have protection for that, although FT said they were coming out with some new ones (made in America even) that would have this protection. I don’t think those are released yet though.

 

[AndyA]

Thanks - great advice! We will try launching it as a glider and try to iron out some of the basic problems that way so we don't burn a third ECU LOL.

 

[Merv]

...Am I right in thinking that the cause of the fires is because the motor is stalled but we were not immediately reducing the throttle, so the motor kept demanding more and more current?...

Yes, that is likely the issue.

Replaced the motor and ESC with versions off Amazon but went with a 1000KV motor instead of the 1250KV the kit came with, thinking it wasn't a significant difference - it was, the plane just wanted to nosedive when taxiing....

I doubt going from 1250 to 1000 Kv was the cause of the nose dive.
I suspect the landing gear was bent backwards a bit. When the plane is level, you want the wheals to be about an inch forward of the leading edge of the wing.

...The windings on the third motor are short circuited. ...

The screws attaching the motor to the X motor mount may have been too long & caused the short. Next time make sure the screws are not touching ANY wires inside the motor.

As others have said, make the plane balance about 1/4 inch forward of the CG marks on the TT.
If you are going to hand launch, have someone else throw the plane. You want them to throw it with 20-30 degree upward angle, with enough force as you would use to throw a baseball 10 yards or so.

Make sure you have the controls going the correct way. Stand behind the plane. When you pull back on the elevator stick, you want the elevator to come up. When you push the rudder stick to the left, you want the rudder to go to the left. If you have ailerons, when you push the stick to the left, you want the left aileron to go up.

All planes are difficult to fly before you get them trimmed out. If you need to hold the stick one way or another to make the plane fly straight, move the trim that same direction you need to hold the stick..

 

[Foamforce]

By the way, is this the Tiny Trainer? You said it was the FT Trainer, so I wasn’t sure if you meant THE Tiny Trainer or A trainer. Maybe it’s the Tutor?

I ask because the Tiny Trainer doesn’t have landing gear. If you made your own, it could be affecting the COG quite a bit.

 

[HVB79]

We replaced the prop, connected the battery and the motor started smoking and the ESC caught fire.

... this time it took off but climbed, veered to the right, dived and crashed on its nose. The ESC immediately caught fire.

Am I right in thinking that the cause of the fires is because the motor is stalled but we were not immediately reducing the throttle, so the motor kept demanding more and more current? Don't the ESCs have current limiting in them to give them some kind of protection?

Having the prop blocked was not the cause of your ESC fires.

You did not even have the prop blocked in the first case as you had just replaced it.
Even if you had blocked the prop the ESC would not have been armed yet as you had just plugged in the battery.

ESCs do NOT instantly start on fire from a few seconds of the prop being blocked. If given enough time with throttle on and a blocked prop an ESC or motor can be damaged, smoke or even catch fire but it will not happen right away.

What will cause an almost instant ESC fire is shorting the wires between the ESC and motor. This results a short that pulls the full current of the battery through the ESC. This will start the ESC on fire after only a few seconds. Common causes are exposed bullet connectors, having a sharp metal edge or screw damage the wires in a crash or physical damage directly to the ESC.

 

[Foamforce]

Having the prop blocked was not the cause of your ESC fires.

I’ve had it happen to me a couple times. Shorting the windings with the screw is another possible cause, but not the only cause. When you burn up the motor from locking it, that shorts the windings too.

 

[Mr Man]

Having the prop blocked was not the cause of your ESC fires.

You did not even have the prop blocked in the first case as you had just replaced it.
Even if you had blocked the prop the ESC would not have been armed yet as you had just plugged in the battery.

ESCs do NOT instantly start on fire from a few seconds of the prop being blocked. If given enough time with throttle on and a blocked prop an ESC or motor can be damaged, smoke or even catch fire but it will not happen right away.

What will cause an almost instant ESC fire is shorting the wires between the ESC and motor. This results a short that pulls the full current of the battery through the ESC. This will start the ESC on fire after only a few seconds. Common causes are exposed bullet connectors, having a sharp metal edge or screw damage the wires in a crash or physical damage directly to the ESC.

If it draws enough amps it will.

 

[HVB79]

If it draws enough amps it will.

The OP states that the first fire happened "instantly" after replacing the prop and plugging in the battery. Even if the prop was blocked and the throttle at 100% the ESC would not be armed and the amp draw would be 0 amps from the motor.

 

[HVB79]

I’ve had it happen to me a couple times. Shorting the windings with the screw is another possible cause, but not the only cause. When you burn up the motor from locking it, that shorts the windings too.

I agree that putting a motor mounting screw into the windings is a great way to burn out a motor. But if that was the case, how was the motor running prior to the first crash if a motor mounting screw was inserted into the motor windings?

 

[Mr Man]

The OP states that the first fire happened "instantly" after replacing the prop and plugging in the battery. Even if the prop was blocked and the throttle at 100% the ESC would not be armed and the amp draw would be 0 amps from the motor.

Sounds like reversed polarity or short-circuit then

 

[Foamforce]

The OP states that the first fire happened "instantly" after replacing the prop and plugging in the battery. Even if the prop was blocked and the throttle at 100% the ESC would not be armed and the amp draw would be 0 amps from the motor.

The OP also stated that it happened after a crash. What probably happened was that the motor burned up when it locked in the crash. Once the motor windings are burnt and the windings are short circuited, then if you give it full throttle, it can burn up the ESC in a couple seconds as well. This specific scenario has happened to me.

If either the motor or the ESC gets fried, it can end up frying the other one. On the ESC side, when any of the six transistors gets fried, they can get stuck in the on state and dump unrelated current to one or more of the windings. Since it’s not alternating the current between the windings, the motor doesn’t spin and it quickly overheats and burns out the motor windings. It can happen the other way too. If the motor has gotten burnt out, then the windings will be short circuiting power which can draw too many amps from the ESC, burning that up.

The lesson is that if one or the other gets fried, carefully bench test a new motor or esc very quickly, checking for heat. If any heat is felt within a couple seconds, unplug the battery to prevent damage.

 

[Foamforce]

The OP states that the first fire happened "instantly" after replacing the prop and plugging in the battery. Even if the prop was blocked and the throttle at 100% the ESC would not be armed and the amp draw would be 0 amps from the motor.

I just re-read your post and you were suggesting that the motor wires between the ESC and motor were shorted. But if the throttle was at 0, then there would be no power going to those wires, unless the ESC was already damaged.

 

[bisco]

We built an FT Trainer from a complete FT kit and everything looked good. Went to fly it and it agressively climbed, then stalled and crashed on its nose and broke the prop.

We replaced the prop, connected the battery and the motor started smoking and the ESC caught fire.

Replaced the motor and ESC with versions off Amazon but went with a 1000KV motor instead of the 1250KV the kit came with, thinking it wasn't a significant difference - it was, the plane just wanted to nosedive when taxiing. We checked the COG and it was fine.

Replaced the motor with a 1250KV from Amazon and this time it took off but climbed, veered to the right, dived and crashed on its nose. The ESC immediately caught fire.

Am I right in thinking that the cause of the fires is because the motor is stalled but we were not immediately reducing the throttle, so the motor kept demanding more and more current? Don't the ESCs have current limiting in them to give them some kind of protection?

What make of ESC should I get that does have protection?

The windings on the third motor are short circuited. Is there a make of motor that is more resistant to instant short circuit when crashing?

Right now the motors and ESCs seem really fragile to us.

Thanks! Andy

who is teaching you to fly?

 

[AndyA]

Sorry!! It is the Tutor! Gah. we have the tail dragger configuration.

Thanks for all of the really helpful replies!

After the first crash we replaced the prop. Thottle was at zero and not armed. Connected the battery and immediate smoke from the motor then ESC caught fire.

We don't have anyone to teach us so we are at the trial and error stage. We really like the idea of throwing it as a glider to try and work some of the issues out so we will try that next. Also we will put some electrical tape over the bullet connectors.

As for screws into the motor, we used what came with the FT kit - the motor and mounting. The ony screws we had to install were the ones to mount the cross piece to the firewall so they were pointing away from the motor.

Thanks, Andy

 

[FoamyDM]

We built an FT Trainer from a complete FT kit and everything looked good. Went to fly it and it agressively climbed, then stalled and crashed on its nose and broke the prop.

We replaced the prop, connected the battery and the motor started smoking and the ESC caught fire.

Replaced the motor and ESC with versions off Amazon but went with a 1000KV motor instead of the 1250KV the kit came with, thinking it wasn't a significant difference - it was, the plane just wanted to nosedive when taxiing. We checked the COG and it was fine.

Replaced the motor with a 1250KV from Amazon and this time it took off but climbed, veered to the right, dived and crashed on its nose. The ESC immediately caught fire.

Am I right in thinking that the cause of the fires is because the motor is stalled but we were not immediately reducing the throttle, so the motor kept demanding more and more current? Don't the ESCs have current limiting in them to give them some kind of protection?

What make of ESC should I get that does have protection?

The windings on the third motor are short circuited. Is there a make of motor that is more resistant to instant short circuit when crashing?

Right now the motors and ESCs seem really fragile to us.

Thanks! Andy

Hi Andy,
It is sad and nostalgic to hear about the difficult times you’ve had getting started.
My AviationRCNoob podcast might help. Or at least help you to know this is common for those brute forcing the learning, using our own cobbled (cheaper) setup.

What battery are you using? The cheap orange-can motors are limited to 3S lipo. The Escs can handle 4s. A 4 cell lipo with one of those inexpensive motors will cause the wires to overheat, melts the Wire coating on the windings and then a short circuit ruins the motor.

The 1000kv motor and 1250kv motors will pull more different flow/Amps from the battery through the ESC. The motor will take what it needs. If the ESC can handle it (30A esc should be fine) everything is fine. If the voltage, or Amps are to high, high heat will melt something and release the magic smoke.

Be sure to check your surfaces are going the correct direction. Flite Test talks about the high five method.

Control check - High five method
When moving sticks from behind and looking at the aileron and elevators, the stick movement should come to give the deflected surface a “high-five”.
Push the aileron left, the left aileron on the plane should deflect up to “high-five” the stick.
When moving the elevator for upward movement, the downward stick movement should yield an elevator deflection upward.
Rudders to follow the stock movement.

Other components
The raised numbers on the prop should face the direction you want the plane to go.

The esc should have some airflow.

If the motor is spinning the wrong way… flip two of the wire leads to the ESC. The 3 wires supplies 5v and ground to the Rx and signal from the Rx to tell the ESC what to do.

Batteries should be at or under the rating of all the components (ESC and Motor)

Lastly CG. Should be where its marked. That means it stays level when balanced on finger tips on those points. It Should be between the 25-33% of the wing chord from the leading edge on straight wings. Use a CG calculator to verify.

Lasty check for twisting. On most planes, the wing should be straight down the length. Or at least symmetrical about the center. The elevator should be parallel to the wing trailing edge. Rudder should be perpendicular to the elevator (v-tails aside here).

That said, is this a FT kit with all the recommended electronics?

 

[FoamyDM]

Sorry!! It is the Tutor! Gah. we have the tail dragger configuration.

Thanks for all of the really helpful replies!

After the first crash we replaced the prop. Thottle was at zero and not armed. Connected the battery and immediate smoke from the motor then ESC caught fire.

We don't have anyone to teach us so we are at the trial and error stage. We really like the idea of throwing it as a glider to try and work some of the issues out so we will try that next. Also we will put some electrical tape over the bullet connectors.

As for screws into the motor, we used what came with the FT kit - the motor and mounting. The ony screws we had to install were the ones to mount the cross piece to the firewall so they were pointing away from the motor.

Thanks, Andy

Also can you post a picture or two showing the electronics? It might help us help you. Also a flight video can help some members tell what caused the nose-in.

 

[HVB79]

The only screws we had to install were the ones to mount the cross piece to the firewall so they were pointing away from the motor.

Are the cross piece mounting screws sticking out of the back of the firewall? I have seen several new builders use screws that stick out the back of the firewall creating sharp spikes ready to stab anything behind the firewall in a crash.

Like this example:

 

[HVB79]

We don't have anyone to teach us so we are at the trial and error stage.

As you are teaching yourself to fly consider the building a pusher style plane like the FT Mighty Mini Explorer. A plane like this moves the motor and ESC out of the nose so they don't get crushed in a crash.

If you have the money a flight simulator (or this one) will help a lot instead of crashing over and over while you learn the basics. A simulator does not help with aircraft setup issues but is a big help with learning the correct stick movements.