First Post: I have a problem

[jhetland]

I ordered some of the kits, and wanted to start with the FT Tiny Trainer to put together.

I have a decent amount of experience flying racing/freestyle quadcopters, but really want to be able to FPV an airplane with its ability to have long sweeping and floaty turns.

I've also flown things like the e-flight vapor around in my backyard with good success, and have even flown with some success a 6 channel plane with no accelerometers or stabilization ( bring these things up to give background that while it totally could be inexperience, i have been able to successfully do something, so it isn't total newb syndrome, and I'm suspecting its more to do with my inexperience building / assembling)

I just took the tiny trainer with the trainer wing on it (sans ailerons) and it went....... terrible. I don't know what i did wrong.

There was a bit more wind than i wanted, but it wasn't crazy and even in launches where the wind died down or launching with the wind had the same outcomes.

With each launch it almost immediately hard banked back at me to the left, turning over and landing either upside down, or on its side breaking away the wing.
The power pod is angled in that direction by design, because the motor spins in the opposite direction, but i thought the dihedral wing was supposed to make it want to level out and fight against any tendency to flip over, meaning something has to be extra bad here that it is doing so much.

I was able to slow down its hard bank one time by steering all the way over in the other direction, it flew forward for like...... 10 seconds and then actually flipped upside down and nosed down, which i suspect means it was really really wanting to turn over and ended up barrel rolling instead of banking

Here is an image of it built, hanging on the wall

any idea what i did wrong, or how to correct it?

 

[telnar1236]

A couple things to check. My first suspicion is that it's your thrust angle. The thrust angle should be in the same direction as the prop rotates since when the prop spins it makes the airplane want to spin the opposite direction. For almost all planes, that means right thrust to counter a propeller spinning clockwise as seen from the back of the plane. This is a rough picture of what's going on as seen from the back of the plane. Basically, the plane wants to spin in the green direction instead of the red direction (the way the prop is spinning). So the thrust angle should be the direction in purple and probably a bit down too.

That said, it's possible that your prop spins the opposite direction to normal, in which case built in left thrust would be correct. As best I can tell from the picture, the prop should spin clockwise, but it's hard to tell from that angle.
If you're confident in the thrust angle, the next thing to check would be to make sure everything is lined up and true. Your build looks good, so I doubt that's the problem though. Other things could be too slow of a launch or too much power before the plane has time to gain speed, but the thrust angle seems most likely.

 

[Mr Man]

The prop appears to be a cw prop, In other words, it;s turning counter-clockwise if its coming towards your face.

 

[MZ250Ben]

How much throttle are you launching with? You don't need much with that plane. In any case, you should glide test it with no throttle, then you'll know whether it's even propeller related.

 

[telnar1236]

The prop appears to be a cw prop, In other words, it;s turning counter-clockwise if its coming towards your face.

Glad you can see that in the picture. Almost certainly a problem with thrust angle then.

 

[Foamforce]

IMO, thrust angle wouldn’t have that dramatic of an effect. @MZ250Ben has good advice regarding the glide test. The outcome probably won’t be as dramatic without thrust, but it will likely still roll left and attempt to nose up. It may be tail heavy along with needing a fair amount of right trim. When you glide test it, you should be able to throw it a fair way and it should go straight with the nose slightly dropping. Post a video! Good luck!

 

[Shurik-1960]

1.Check: the wing plane must be in the same plane as the stabilizer. 2. The rudder must be positioned strictly along the axis of the fuselage and perpendicular to the plane of the wing (stabilizer). 3. The screw must rotate counterclockwise (front view of the model) 4. The motor is tilted 3 degrees to the left and 3 degrees down (front view of the model).5. Check the correct installation of the screw: the screw should rake air onto the model when rotating counterclockwise (view from the nose of the model). If everything is in order, we switch to planning and adjust the smooth flight with weights.When the model is planning smoothly and perfectly, we make the first flight: we throw it into planning and smoothly add gas .The model should fly smoothly, slowly gaining altitude. By following these rules, you will cease to be new models on your first flight.Good luck.

 

[Merv]

...how to correct it?

Try moving the CG about 1/4 inch forward of the recommed spot.

 

[jhetland]

thank you so much. Based on what you described i looked at the nose and adjusted it a bit.

After your reply i looked at it and here is how it was configured from the top.
The tiny trainer precut kit has the motor pointed to the left (from the top down, this is exaggerated to illustrate it).

The motor was spinning in the same direction as the angle, which is the side it was leaning hard towards.

I changed the direction of the motor to spin in the other direction and did some very short backyard powered glide tests, it still felt like it was pulling to the left, but not nearly as bad, with some right rudder it would fly straight but it still wanted to turn over to the left.

I'll need to get back out to somewhere with some space to see if i can get it into the air for real. My backyard is too small, all i could do was try to get it to fly straight, close to the ground for about 100 ft.

 

[jhetland]

How much throttle are you launching with? You don't need much with that plane. In any case, you should glide test it with no throttle, then you'll know whether it's even propeller related.

i think i was probably hot on the throttle

 

[Piotrsko]

100 ft is enough space for a test glide. 1:1 ratio glide from 6ft high launch would be 6 ft away. it takes 16:1 to go 100 ft. If you're getting 16:1 glide, you're outperforming my sloper, and it ain't turning or doing weird stuff.

Gentle.toss. you want a touchdown about 40 ft away

 

[Foamforce]

The TT powerpod is designed with a right thrust angle, not left. You may have installed it upside down. The open side of the power pod should be up. The other possibility is that it crashed and squashed it, changing the angle. If that’s the case, I would recommend downloading the free plans and making a new power pod. It’s pretty quick.

You said you reversed the motor. Did you do that by switching two of the wires? After that, did you turn the prop around? If you did, that won’t work. Props only produce good thrust in the correct direction, which is numbers forward.

Regardless, I agree with @Piotrsko that you should start with an unpowered glide test. That will verify that your airframe and trim are all working properly. Once that’s good, then you can focus on thrust angle. Tackling one problem at a time makes debugging easier.

Good luck!