"Juan Jimenez" wrote in message
...

"Morgans" wrote in message
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"BobR" wrote

Probably lots of different reasons why it has not achieved the flying
success it should have but you hit on the biggest and probably most
important, no suitable engine. Yeah, I know that there are now many
good engines that could power it well but its time was then and this is
now. It was ahead of its time then and the needed engine wasn't
available.

I don't think that is quite true. There may be better engines now, but
that is only part of the problem with the piston engine in the BD-5.

The link escapes me now, but there were tremendous problems with
torsional harmonics, tearing apart everything, all the way along the
drive train.

No BD-5 has suffered an inflight failure involving either the airframe or
the drive train hardware.

Correct, but that statement avoids the issue. There are/were unsolved
torsional problems. During the so-called development period for the design
they fought a number of problems including broken drive shafts, broken
engine mounts, etc. which were results of various torsional issues which
were never completely resolved.

http://www.prime-mover.org/Engines/T.../contact1.html

The only reason there were no in-flight failures of drivetrain hardware is
that the people involved with the design, both the Bede team and tinkerers
over the last 30 years have been dilligent and lucky enough to identify
failures and pending failures on the ground, rather than discovering the
failures in the very rarely demonstrated airborne mode of the design.



Beef up the driveshaft, and the clutch tore apart. Fix the clutch, and
the engine mounts cracked, beef them up, and something else broke. So
on, and so on.

Anyone happen to have the links handy that addressed all of these issues?
It was a very interesting read, although a lot of material. I think they
would answer, with great detail, why the 5 never caught on. They self
destructed.

My web site includes a library of material that includes things like this.
Help yourself, that's why I put it there, the good _and_ the bad.


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