Since some years i think about a rigid chest strap for a reduction of twist risque.
The last year with Pascal Valley, we did some acro test with his paramotor and we were impress by the rigid comportment during the spin triks.
I made the first test during the winter 2010/2011 with the wood bar, and Gill SCHNEIDER push the test this winter with a better shape bar.
After the test i think it s can be nice in acro in some way, but i advice for beginning acro more safety.

test : rigid chest straps from Jb test fly on Vimeo.

The feel back :
- no problem during the take of
- hard to twist during the flight.
- no one change in dynamic tricks
- a real security during the spin tricks ( mac twist, helico, misty … )
- it s change the feeling during the spin tricks ( helico, the helico link and misty )

the positive points :
- diminution of twist risque
- during the twist, the bar push for come back in normal way.
- a possibility to push faster some tricks ( twister, sat to heli, mac twist )
- safety for learn some tricks ( full stall, spin, helico, misty, mac twist … )

The negative points :
- the twisty misty can be really harder ( we don’t test ir )
- the helico landing can be also a problem ( we don’t test it )

If you are interesting, test it, it s easy to build
cheers