Scratch build planes keeps twisting side ways

[Dude]

Hi to all,

I have been doing a couple of scratch builds and I have been having an issue that they twist side ways as if they had a rudder(which they dont), it keeps going into circles and into the floor. The planes have been check for the CG and it is ok but still, when i hand launch it it twists out of control. Any recommendations?

 

[bicyclemonkey]

You don't happen to have a video of this, do you?

 

[pgerts]

Picture of the plane? Or link to drawing? Best of all a movie.
Twist - is it yaw or roll?
Circles - is it rolling or flat spins?

 

[bicyclemonkey]

You mention that it's when you hand launch it, it twists out of control...As in a torque roll to the left from too much motor? I have some small foamie warbirds that veer to the left when I hand launch them.

 

[Dude]

no i dont have a video. It twists as in yawn. Not roll. I also thought it could be to much torque but even at half stick it spins

 

[bicyclemonkey]

I'm assuming the vertical or horizontal stab or main wing are all glued on straight and not at any angle?

 

[FlyingMonkey]

The obvious answer is that you could have the vertical stabilizer attached slightly crooked, or it has a slight warp in it.

You could have the plane slightly off balance on the side it turns towards.

You could have too much right thrust in your motor.

Those are the three guesses I have without seeing the plane or it's flights.

 

[bicyclemonkey]

I'm just throwing this out there as an example but you want to make sure these measurements are accurate:

 

[NickRehm]

If all else fails, add a rudder and trim it out

 

[colorex]

If the fuse is warped, it may act as a rudder...

 

[Jeffrey Saelee]

If it is a 3D plane or something, try this: http://static.rcgroups.net/forums/attachments/1/9/2/2/4/2/a2401567-145-DSCN0152 small.jpg (Sorry embedding it doesn't work)

 

[pgerts]

No fin at all?

 

[Dude]

Yes a small fin, i will re assemble it with the information provided. Thanks alot everyone! It has been of great help!!! When i assembled it the first time i didnt take under consideration so many details