On 1/4/2007 3:21:53 PM, "Morgans" wrote:

"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.

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.

Van's RV-4, RV-6, RV-7, RV-8 and RV-9 aircraft. Those
aircraft were slightly bigger, appealed to more pilots, were easier to
build, used proven available engines, offered performance galore and
were far easier for the average pilot to fly.

Although I have never flown one, the experienced pilots that did said things
like; it would eat most people alive, that it scared them, and so on.


Are you thinking about this one?
http://www.prime-mover.org/Engines/T.../contact1.html
I ran across it while doing a little research prior to this post.

I think all piston engine designs suffer too much from torsional vibration
problems. But most are just not serious enough to be destructive.

--
Whome?