I'd like to be wrong but I've seen Laithwaite, Hayasaka (sp?) and at
least one other make similar devices, all of which failed when tested
away from their original rigs. Measured forces proved to be due to
friction, erratic vibration and in one case, the exhaust from the model
aeroplane engine powering the prototype. :-)
I know you won't have made that basic a mistake, but you're up against a
*very* hard problem here, at the very least.
Bob Grahame : <bdg@mm-croy.mottmac.com>