Another tailwheel discussion

[av8rps]

You know Jeff, that makes a lot of sense. I think that might be another piece of this puzzle.

Personally, I am beginning to believe the issues some of us have experienced were probably related to caster angle, spring tension, rudder deflection, gear alignment, or any combination of all of the above.

More and more I'm starting to think that someone really needs to make it much clearer to builders and flyers just how critical any or all of these things can be to sucessfully operating a tailwheel airplane...

It would be nice to see the tailwheel manufacturers do a better job at providing that information proactively, rather than to let some learn the hard way...

Tailwheel Caster Angle:

Even if the tailwheel is unlocked, if the caster angle of the pivot is correct,
THEN the airplane will will land perfectly normally ... Since the correct
caster angle will make the tailwheel straighten right out.

It would only ever have a tendency to make the airplane turn, if the
caster angle is incorrect.

So I would assert that if an unlocked tailwheel is causing the plane to
go off course, then the caster angle of the tailwheel is incorrect.

The exception to this is if you are countering a strong crosswind on the
ground with the tailwheel, then it unlocks and rudder alone cannot keep
it straight.

Jeff

[Av8r3400]

The reason for my ground loop was tailwheel shimmy, which caused the wheel to unlock.

The shimmy was induced by a sagging tail spring, which caused the king pin on the wheel to have an excessive positive caster.

Look at this helpful photo…

[KFfan]

A quote from Matco site:

"The assembly should be mounted on the flat spring so that the pivoting axle is as close to vertical as possible when the plane is loaded".