Ground loops with tailwheel planes.

[Captain Ed]

I can't seem to avoid ground-looping my tailwheel planes. I've practiced taxiing on my street and I most always veer off to the left or right with a ground loop as a result. Do I have a technique problem or is there a design remedy that can help. I usually use a non-steerable tailwheel or skid. My main gear is generally aligned with the leading edge. Thanks in advance for the advice. Ed

[DeaninMilwaukee]

A big factor is how nose high the plane sits with the tailwheel on the ground.

The bigger the angle, the easier it is to ground loop. If you notice, when you do manage to get going, as soon as the tail lifts, ( removing almost all the angle), you barely need to add any rudder after that.

Try lengthining your tailwheel mount to hold the tail higher so that the plane is close to level sitting on the ground.


Dean in Milwaukee

[DaveSawers]

Move your main gear back a little. When the model is on the ground with the tail lifted, the wheels should be underneath (or just forward of) the CG.

As Dean says, the problem is magnified if the at rest angle is high because that puts the main gear well forward of the CG.

[Viper Pilot]

1) Make sure you have some toe-in on your main gears.

2) Apply throttle slowly at first.

3) Use up elevator until speed is up.

Viper

[ChrisP]

In 40 years of R/C flying the only thing that has ever worked for me has been a steerable tailwheel or skid.

If it's still squirrely, then I take off from grass and not concrete.

I always had a hankering to try a gyroscope on rudder, but never got round to it.

[tim hooper]

Capt Ed,

I asked a similar thing a little while ago;

http://www.rcgroups.com/forums/showthread.php?s=&threadid=107282&highlight=torquesteer

tim

[Captain Ed]

Tim, I checked out your thread. Lots of spirited discussion for sure.
I'm finishing up a scratchbuilt and installed the wheels and a temporary skid. I read the advice about locating the wheels as close to the cg as is practical but I fly off grass and that tends to cause the plane to tip over at times, which is why I put the mains near the leading edge. Anyway, I did some taxi runs with the new machine and it exhibits the typical tailwheel tendencies - especially swapping ends when the throttle is cut. I replaced the skid with a steerable tailwheel and taxied it again with much better control, in fact it's better on the ground than any other previous plane I've built. Most of my planes I've removed the gear from altogether, but its real tough on props (especially the takeoffs - :D ) Ed

[Fallen Angel]

toe in works for me.