Lynn,
What is a “Dutch clamp”?
Bill B
From: Rotary motors in aircraft
[mailto:flyrotary@lancaironline.net] On
Behalf Of Lynn Hanover
Sent: Sunday, October 11, 2009
4:25 PM
To: Rotary
motors in aircraft
Subject: [FlyRotary] FlyRotary]
Re: where's the missing power?
I realize that the Drummond dyno exhaust system is sized
to get maximum power at much
higher rpm (9000+) than we use but can you give us approximate tubing
diameters and lengths
of both the primaries and collector of the Drummond system then pulling
from your many years
of "Real World Experience" recommend tubing diameters
and lengths sized for our aircraft
systems (perhaps one for the 2.17 re-drive that spends most of the time
at 5000 to 5500 rpm
then one for the 2.85 re-drive typically used at 6000 to 6500
rpm)..............
--
Kelly Troyer
"Dyke Delta"_13B ROTARY Engine
"RWS"_RD1C/EC2/EM2
"Mistral"_Backplate/Oil Manifold
The goal will be the scavenge effect and not actually pumping up torque
at lower RPM. So any system that does not screw up the scavenge effect should
be a huge improvement. So one system design should work fine for either
reduction ratio.
This all conjecture since I no longer have a dyno. But, I would use
1/7/8" ID primaries of 18" to 22" into a long collector
maybe 8" ending at 2 1/4". Then a smooth transition to a flex pipe
(to allow for engine moving in the mounts) then to the end of a fixed down tube
of 2 3/4" clamped to an engine mount tube with Dutch clamps.
A streamlining cuff over the down tube with air holes for cooling. Then
into a Bomb style muffler with the cooling tube through the center as seen here
on the news group. I would use crossed fish tails so as to look like ordnance.
With air along the outside and through the centerline, plus the distance from the
engine, muffler failures would be reduced. Plus there would be less heat inside
the cowl. No dripping liquids would be set alight. More room for other items to
fit.
If it does fall apart the worst that could happen is that it falls off,
never to be seen again. Just don't put your tail number on it. I would have the
cooling center tube turned through the centerline to disconnect the cooling
tube from the exhaust note.
The important part of the build is to get the primary pipes exactly the
same length to the collector.
I can do drawings if you like.