The Wittman gear is the flat or tubular main gear used on Cessnas and
Tailwinds.

--
Cy Galley, TC - Chair, Emergency Aircraft Repair, Oshkosh

Editor, EAA Safety Programs
or

Always looking for articles for the Experimenter

"Corrie" wrote in message
om...
"Rich S." wrote
It may have something to do with the rebound spring.

I think you're probably right. From what I can see of the pictures
and drawings, it's probably sized to damp the natural frequency of the
big spring, which is sized to damp the natural freq. of the small one.

It might be possible to screw up the gear with differently-massed
struts, wheels, brakes, tires, etc. so that the resulting natural
freqs synch up, yielding undamped divergent feedback. (Remember the
films of Galloping Gertie, the Tacoma Narrows bridge?) We had those
kinds of problems in my Statics and Dynamics classes back in college.
But they always made my head hurt. ;-)

Rich, in the Emeraude plans, how specifically are the springs called
out? Do they specify the stiffness (or the spring constant, may be
the same thing), as well as the dimensions? (By way of contrast, the
gear-retraction system of the CA-65 uses a garage-door spring , hardly
a tight specification. But there's not likely to be much occillation,
as the spring is just a mechanical assist while cranking up the gear.

BTW, a newbie question. What's a Wittman undercarriage? I know Steve
Wittman's name and that he was a major contributor to the field, and
I've seen lots of references to "Wittman undercarriage" but what
exactly IS this wonder-invention?

Corrie