plane doesn't go straight

[Belial2801]

hello, some time ago I had a problem with my first plane because it didn't move straight, I stopped the project and a few days ago I thought I had it ready so I tried it and surprisingly it moved straight (I tried it without the wings), today I built the plane (with wings) and the problem continued, I think it is due to a problem with the wings of the plane since it always goes to the left side. How could I fix it? This happens when trying to take off so I haven't tested it in flight

 

[Foamforce]

Do you mean while taxiing on the ground? If it’s at low speed, it’s usually the wheels being out of alignment. You’re saying that it goes straight on the ground if the wing isn’t on it? It could be that the added weight of the wing squats the plane down on the landing gear and bends it. Your landing gear wire might be too light in that case.

 

[Belial2801]

Do you mean while taxiing on the ground? If it’s at low speed, it’s usually the wheels being out of alignment. You’re saying that it goes straight on the ground if the wing isn’t on it? It could be that the added weight of the wing squats the plane down on the landing gear and bends it. Your landing gear wire might be too light in that case.

yes, taxiing on the ground, without wings the plane goes straight but when adding them it turns to the left, I realized the problem with the landing gear and I added some reinforcements so it stays in place. I recently added some weight to the right wing and that seems to compensate for the spin but I don't know if that is the final solution. They also told me that it could be due to the torque of the engine and that I only have to compensate with the rudder but I feel that the turn is very strong because it begins to make circles

 

[Foamforce]

Try taxiing as slow as you can go and if it still goes left strongly, it’s probably the wheels. I wouldn’t add weight to one of the wings because that could affect your flight. If your landing gear wire was too light, I would probably replace it with some heavier gauge stuff.

What kind of wire are you using and which plane is it?

 

[Merv]

Make sure both wheals are spinning freely.
Try adding some toe-in, that is have both wheals pointing to a point 5-10 feet in front of the plane.

 

[Belial2801]

Try taxiing as slow as you can go and if it still goes left strongly, it’s probably the wheels. I wouldn’t add weight to one of the wings because that could affect your flight. If your landing gear wire was too light, I would probably replace it with some heavier gauge stuff.

What kind of wire are you using and which plane is it?

It's the piper cub from flite test, I don't know how to say it in English but I think it's called a coat hanger, it's made of metal and I added some reinforcements so that the weight of the plane doesn't affect it, but I still wonder why without wings the plane goes straight but when putting them on the problem returns.

 

[Belial2801]

Make sure both wheals are spinning freely.
Try adding some toe-in, that is have both wheals pointing to a point 5-10 feet in front of the plane.

I will try

 

[RossFPV]

sometimes planes will turn left when on the ground due to the rotation of the air from the prop hitting the plane. I guess it makes sense that it happens most with the wing on because its a much bigger surface for the air to hit. Ever tail dragger plane i had turned left on the ground but flew straight in the air, just hold some right rudder to keep it straight until your in the air.

 

[Belial2801]

sometimes planes will turn left when on the ground due to the rotation of the air from the prop hitting the plane. I guess it makes sense that it happens most with the wing on because its a much bigger surface for the air to hit. Ever tail dragger plane i had turned left on the ground but flew straight in the air, just hold some right rudder to keep it straight until your in the air.

Good point, I corrected the landing gear once again and it has reduced a lot when using the rudder, I'll try another prop just to confirm, thank you very much everyone for the help.

 

[tamuct01]

sometimes planes will turn left when on the ground due to the rotation of the air from the prop hitting the plane. I guess it makes sense that it happens most with the wing on because its a much bigger surface for the air to hit. Ever tail dragger plane i had turned left on the ground but flew straight in the air, just hold some right rudder to keep it straight until your in the air.

This is standard behavior on nearly every single-propeller tractor setup. It's called P-factor: https://en.wikipedia.org/wiki/P-factor
You will likely need to apply some right rudder on takeoff to counter the effects.

 

[quorneng]

Just remember the P-factor is due to the rotation of the prop. if for any reason you fit a prop that goes round the other way, i.e. clockwise viewed from the front, then the plane will tend to go the other way on take off and need left rudder.

 

[mastermalpass]

It's the piper cub from flite test, I don't know how to say it in English but I think it's called a coat hanger, it's made of metal and I added some reinforcements so that the weight of the plane doesn't affect it, but I still wonder why without wings the plane goes straight but when putting them on the problem returns.

Coat hangers are my go-to for landing gear material! The only limitation is that on larger planes needing longer struts, the material is a bit too heavy and a bit to easy to bend out of shape, but for the FT Cub, it should be fine.

I never expect a straight run when rolling on the ground, I'm actually surprised your plane can go straight at all, wings or not. As others have said; don't add weight to the wing. If you really think it will help, then balance the fuselage on your finger tips and see how quickly it wants to tilt to one side - that will tell you how the weight balances out in flight, which is where it really matters.

When you roll on the ground, P-factor, torque and bumps in the road will be turning your plane anyway and once you're up, torque and P factor will still be there to turn it off-course. So it's best not to go adding asymmetric weight into the mix as well.

 

[Belial2801]

This is standard behavior on nearly every single-propeller tractor setup. It's called P-factor: https://en.wikipedia.org/wiki/P-factor
You will likely need to apply some right rudder on takeoff to counter the effects.

Thanks, I didn't know about that.

 

[Belial2801]

Coat hangers are my go-to for landing gear material! The only limitation is that on larger planes needing longer struts, the material is a bit too heavy and a bit to easy to bend out of shape, but for the FT Cub, it should be fine.

I never expect a straight run when rolling on the ground, I'm actually surprised your plane can go straight at all, wings or not. As others have said; don't add weight to the wing. If you really think it will help, then balance the fuselage on your finger tips and see how quickly it wants to tilt to one side - that will tell you how the weight balances out in flight, which is where it really matters.

When you roll on the ground, P-factor, torque and bumps in the road will be turning your plane anyway and once you're up, torque and P factor will still be there to turn it off-course. So it's best not to go adding asymmetric weight into the mix as well.

I decided not to add weight because I think that it will affect the flight, all this information was very helpful, thank you very much everyone