Ft tiny trainer won't fly

[Pickowicko]

So I finally finished building my tiny trainer from the plans and took off after charging my batteries to full. Low and behold when I power the motor up and launch it flys straight into the ground. It does this over and over again with different batteries and motors. I am using a zippy 20c series 1000 3 cell li-po, a 2300kv motor,turnigy reciever and a 12A Afro esc. I don't know if it is to heavy as it weighs 307 grams. Can someone please give advice as it has been a stressful build experience attempting and almost breaking the plane each launch.

 

[bhursey]

Check CG also make sure the prop is the right way if the motor is not turning the wrong way. One way to test it is to throw it without the motor on and see if it glides. same will help you figure out cg it should glde straight. if it nose dives adjust cg or trim.

 

[Pickowicko]

Tried it all

I've been adjusting the chug all day and even without a motor it nosedives. The motor is definately the right way and changing the direction made no difference is 307 grams too heavy

 

[ME_Eng_NY]

Did you calibrate the ESC so you are getting max thrust? When you say it nose dives without a motor, what exactly is happening? Are you throwing in up on an angle and then it dives straight down on a stall, or does it automatically dive down?

 

[ztoon]

I've been adjusting the chug all day and even without a motor it nosedives. The motor is definately the right way and changing the direction made no difference is 307 grams too heavy

I don't think weight is the pb. 307gr is not the lighter possible but is doesn't matter at all.
The same way, motor esc and battery doesn't matter at the moment, you should be able to toss it for a small glide without motor.
Sounds (like bhursey said) more like a CG pb.

If motor and/or propeller spins the wrong way it must have made a difference:
- motor & prop (numbers facing aft) reverse = full thrust backward
- motor rv = poor backward thrust
- prop rv = poor thrust

If you haven't already, check FT beginner video series, it is a goldmine.

 

[Pickowicko]

All calibrated I go to full throttle and then it goes into the ground. I've adjusted the cg and it now glides and then it noses down

 

[ztoon]

I've adjusted the cg and it now glides and then it noses down

It nose dives when you apply power?

 

[Pickowicko]

I'm going to try and angle the motor up so it will stop nosediving immediately

 

[Pickowicko]

It nose dives when you apply power?

I'll try throwing it and then applying power maybe from a second floor window.but yes it does

 

[cranialrectosis]

Do you have your elevator channel reversed?

 

[BridgeInspector]

My first thought is to check your controls.

 

[Pickowicko]

Do you have your elevator channel reversed?

Yes when I push down the elevator goes up

 

[Smithereans]

Hi Pickowicko,

Where are you placing your battery? I am using a 800mAh 3S and have to place it as close to the recommended CG as possible to get the plane to balance right. If I remember correctly, the suggested battery location is directly under the power pod, and that placement probably would only work for a smaller 2S battery.

 

[Pickowicko]

Hi Pickowicko,

Where are you placing your battery? I am using a 800mAh 3S and have to place it as close to the recommended CG as possible to get the plane to balance right. If I remember correctly, the suggested battery location is directly under the power pod, and that placement probably would only work for a smaller 2S battery.

I place it so the front is just behind the power pod so it is very far in

 

[Ross]

Post a picture, are the wings in the appropriate place? If you are right on the CG on the plans you should be good, maybe the wings are to far aft?

 

[bhursey]

Yes when I push down the elevator goes up

It should be revers to that when you pull back on the stick the elevator should go up. When you say mush down you mean toward you?

 

[Pickowicko]

It should be revers to that when you pull back on the stick the elevator should go up. When you say mush down you mean toward you?

Yes

 

[Daemon1954]

It is possible to have a misalignment between the wing and the horizontal stabilizer that would cause this issue, if this were the case CG will not have much effect. My cub had a similar problem but reversed it would only stall... .

 

[Pickowicko]

It is possible to have a misalignment between the wing and the horizontal stabilizer that would cause this issue, if this were the case CG will not have much effect. My cub had a similar problem but reversed it would only stall... .

Ok so now I've got it to fly but only for about 10 seconds. It kind of flies down more slowly but even the tinniest amount of elevator control it stalls so I can't get it up in the air. This tiny trainer has not gone well

 

[cranialrectosis]

My first tiny trainer did not do well.

Every time I tossed it, it pitched to the right. I would give it left roll and the plane would roll hard right and nose into the dirt. It was ugly.

I had my aileron channel reversed. I checked it 30 times knowing how it should work and I still got it backwards. When I gave the plane left stick to counter the left tilt, the plane went harder to the left and being so close to the ground, it was not recoverable. If you have your elevator channel reversed, when you pull back on the stick to raise the nose you would be raising the tail instead and pitching face first into the dirt. I did this over and over and over and boy was it frustrating.

I took my plane to the local club. The trainer guy there reversed the channel, added 60% expo and reduced my rates to 50%. He then tossed my plane into the blue under full throttle and trimmed out the left roll with a trim switch in the first pass.

Now when I toss my tiny trainer into the sky, I run WOT (1806 2280kv and 6030 Gemfan on 3S) and my bashed and crooked 355 gram plane flies a nice straight line. The plane will fly by itself with my hands off the sticks and it took that guy at the club all of 6 minutes to get it this way.

If you have a local club, go there. If not, post video of the problem. Let us see in video your sticks and your flight surfaces moving in the same shot so we can confirm that you don't have a channel reversed (this is soooooo common ). Show us in video your CG with the lipo in place. Let us see the front of the plane so we can confirm that you have the motor tilted to the right (not down) to offset torque.

You need to run high expo and low rates if this is your first time flying. Tone the TT down by cutting the rates to 60% and running at least 30% expo. If you don't do this step, the tiniest touch on a control surface will have huge and dramatic effect making the plane HARD to fly. You are not going to trim out this plane at 100% rates. It's just too twitchy.

Most likely you have a CG problem or a reversed channel and too high rates with not enough expo or, like I did, some combination. All are simple to correct VERY common newbie issues. Your local club has that guy who can fix this in 5. Otherwise, post some video so we can see the issue and be more help.