Subject: My FWF design so far
From: rotaryeng
Date: 4/13/2014, 12:04 PM
To: AAA-rotaryeng



 Paul,

 You hit the nail on the head. The look of this plane was 100%
 inspired by what I thought would look good. Basically it's a WAR
 Replica aircraft with a composite fuselage (as opposed to wood
 frame), and a rotary instead of a 0-200 or comparable. I wanted a
 aircraft that was uniquely my own so I picked the planes I liked the
 most (Corsair, Spitfire, Mustang, Fw-190) and combined all the style
 elements that I liked into one plane. And yes the cowling was most
 definitely inspired by looks not practicality but the volume the
 radial style cowling offers is it's own practicality. I tried raising
 the engine up until the spinner was tangent to a curve that was drawn
 from the top of the firewall and looked at component locations. About
 the only thing that didn't give me an immediate headache trying to
 figure out where it would go is the alternator.

 As you can see in the attached screen grab there isn't much room
 between the firewall and the main spar (which goes all the way to the
 bottom skin). The grey tube is your ejector and there just isn't any
 room for it unless I hang it under the plane. It looks a lot bigger
 when placing it right up against the rest of the plane. I wear size
 13 shoes and having a tunnel go between them although plausible would
 make me want to jump out of my skin (I'm slightly claustrophobic) if
 I couldn't have any room for my feet side to side. I have built a
 mockup of the cockpit if you were wondering.

 I moved the exhaust outboard a little and that allowed the center of
 the ends of the motor mount tubes to get within about 1" of each
 other at the motor mount plate. Hopefully that will be enough. It
 does require a bulge on the side of the cowling. Aircraft design is
 all about compromises and the bulge is the one I'm most comfortable
 with. I can live with it being a little noisier and having a little
 higher fuel consumption. In exchange I get a whole lot of space to
 put everything and a good looking plane as well. And the bulge will
 add a little more Fw-190 to the flavor.

 So basically unless there is some major functionality issue that
 hasn't been mentioned yet I think my basic course is set.

 Will Aldridge

 That's a beautiful airplane no doubt about it.

 Please send me the 3DM on the pilot.

 Paul Lamar


 Paul,

 It's pretty crude but you're welcome to it. It's roughly a 95% guy.
 Maybe about 6'2". I measured myself to make him and broadened the
 shoulders and hips a little and made him slightly taller just so I knew
 there would be some wiggle room in the cockpit. And he's wearing size
 13 shoes.

 Will

 Thanks. He is about my size with the same shoes :)

 I think you might have problems with the muffler. Most people do.

 Could you make the fuse a little deeper oval?
 The intersection drag with the wing would be less and you could get the
 muffler in there.
 I'll get my Hoerner Fluid Dynamic drag out and scan it shortly.

 Not the whole thing of course.

 Paul Lamar

The design although not quite set in stone is at least set in foam.  I've already started building the fuselage and wing
spars.  I have a build thread on homebuiltairplanes.com here: http://www.homebuiltairplanes.com/forums/member-project-logs/16831-wa-1-2-spitsairwulfstang.html

So although it hasn't been glassed yet it's still pretty much in final form.

I had an idea that you will probably shoot down but it involves a ovoid ejector of smaller diameter than your design and much shorter.  The screen caps will show better than words.



Above you see the ejector (made from 4" tube split in half with flat sides) and the intake duct.



Above shows the ejector removed so you can see the headers which would have the swiss cheese holes in them.




And the last shows what it would look like with the cowl on. Not shown in the pic is the cutout in the side of the fuselage.

This was very quickly roughed in just to give the general idea.  Is this in any way feasible?

You mentioned that most people have trouble with their mufflers and I'm wondering what they are?

Thanks,

Will Aldridge


Very ingenious ejector. Solves the motor mount problem too.

That will work of course but I doubt it will be quite enough.

The six foot coax ejector is not exactly quite. It just has a more pleasant sound.
This too may have a more pleasant sound but I doubt it will be quiet enough.

We get lots of complaints about the noise. The six foot coax muffler is barely acceptably quite.

Basically they melt from the 1400 t0 1700 F heat.

Paul Lamar

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