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?

Lynn,

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)..............

Thanks,

--
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.

Lynn E. Hanover