Thomas,
Sounds like you're making good progress. The 20B makes a great a/c engine. Biggest problem is cooling. Pay close attention to size and placement of radiators & plenum design. And don't underestimate the oil cooling requirements. That's 1/3 of the cooling load. Make sure the heated air can get out of the cowl.
I think the jury is still out on the "perfect" muffler. The only thing that I know that works is a turbo-charger as it homoginizes the exhaust pulses. But up till now, those have been problematic, and they're heavy. The fishtail may work, if you can design it to survive for any length of time. Ed Anderson tried it and it self-destructed in a very short time. But then I don't know the details of his design (the devil's in the details). Also, Al G's Velocity has a nice muffler/resonator arrangement that seems to work well. May be worth a look.
The p-port design solves a lot of the intake design headaches. You'll have to fabricate a slide throttle, but those are pretty straight forward and can be built with a standard drill press. Then you use three 180* bends to get the intakes up and over the engine (to the cool side), then into a plenum/filter and you're done. Much easier than fabricating a six runner side-port manifold.
Good luck and Happy Thanksgiving,
Mark S.
On Tue, Nov 17, 2009 at 10:28 PM, Thomas Mann <tmann@n200lz.com> wrote:
Well there ya go Mark…….. just the person I need to talk to.
I’m still building my canard aircraft. I just came up out of the basement/shop after putting in another 4 hours on my split canopy frame plug. I should have my mold layup complete this weekend and a CF version of the frame by the end of Turkey Day weekend.
My power plant of choice is a 20B P-Port. I have the PSRU from Tracy and an engine mount from the Cozy Girrrls.
I’m tracking the two big issues on my mind as I work towards the engine part of the project.
Intake and Exhaust.
I really like the cool side intake design. Is anyone fabricating this for a 20B or is it a DIY project.
As far as exhaust, I find the fish tail design interesting. I wonder if the exhaust was split out into a flat wide pattern projecting the sound into several directions at once if it would dissipate the sound waves enough to result in a quieter result ………. Or maybe just annoy more people at the same time.
I’m hoping to be addressing this in the spring.
T Mann
Here is the company that has the tube bends in aluminum and stainless for intake and exhaust systems.
The intakes may be Siamesed to require only three tubes over the engine just like a Periphery port housing. The disadvantage might be a bit less power but probably still over 300, and the advantages are,
you don't take the engine apart, you don't change the design, and you don't weld on the rotor housings.
The three runner tubes can be joined in a flat sided log manifold with a big automotive throttle body on one end.
Since dozens are flying with a throttle body and no difficulties the slide throttle seems less important.
While not built to reduce engine noise, the waste gate exhaust pipes on CART Indy cars were designed to fit between the bodywork and a rear tire. A narrow gap. So the outlet is a stack of 3/4" square tubing stacked up welded and of course chromed. No chance for a flutter failure there.
The Cozy Girrrls make some great pieces.
Lynn E. Hanover
From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On Behalf Of Mark Steitle
Sent: Tuesday, November 17, 2009 8:46 PM
To: Rotary motors in aircraft
Subject: [FlyRotary] Re: Ping
Thomas,
Some of us are still hanging around reading/sending emails (when we should be working). Maybe there are a bunch of us that don't have time to email because we're hard at work on our projects. Could happen.
Personally, I've been making some mods to my cooling system by changing from two coolers in series to two parallel loops. It required some additional AN fittings, so I am waiting for my order from Earl's.
Also, in my spare time, I'm working on building up a new p-port 20B, including a new tangential muffler and slide throttle. Lots of irons in the fire right now. Received my new apex seals today... waiting for the TES o-rings from Creavey Seal.
Mark
On Tue, Nov 17, 2009 at 4:47 PM, Thomas Mann <tmann@n200lz.com> wrote:
Did everyone leave for Thanksgiving already?
|