B Warren's clutch design copied from China? From his group list..



Reading an advertising of a slight damaged Diamont DA-20 from a Shandong
Flight Academy in China,after some inspection (it had a prop strike) and no
apparent damages to the fuselage but some major repair will require to
repair one wing, we decided to purchase the aircraft and shipped it to
Australia. We ordered a wooden box for its transport and while waiting for
it, we had the engine/box removed to be serviced and a full inspection of
the PSRU. The engine is an EJ255 DOHC N/A and Dyno certificates shows
developing 240HP @ 4800RPM, the PSRU is a SubAir D3 and to our surprise it
had a B Warren clutch in it..! We made an appointment so see the engine/box
makers, as it turns out, he was on businesses travel in Russia and not
available. Second best was the engineer, Swen; the German engineer told us
the box is actually a reversed engineering for some box in NZ and already
know to us widely used in China with no apparent problems expect prop
strikes ever so often and the boxes rarely suffer and damages. According to
Swen boxes are replaced even if no problems are found.. Seeing personally
the Dyno test performed on the clutch I found it odd claims that past the
5000RPM the centrifugal weight can dislodge from the blocks, at that RPM the
weight are waged between the clutch plate. We had our box tested at 8000 RPM
with no apparent problems. Since we had to wait for the box to be delivered,
and my pilot license is not valid in China, flying was arranged with an
instructor to be familiarized with the craft, talked to several instructors
and no reported problems with the clutches.

Marc Wiese