That's the part that concerns me the most in building one of these.

I've heard the baffling can be a little...wait for it...baffling.

I'd love to see your final design. If I ever build an Airdrome plane, the baffling will require some major jiggery pokery on my part.

The good news is that there is no shortage of advice - and, amazingly, all of it good - on baffling and decisions I've made.

Indeed, they observed that I've overbuilt myself in a bad way - but that the fix is simple. Then again, it's always easier to remove stuff than to add it on.

Deacon, here's my much smirked upon solution for baffling:



The engine area is now split in two, making a high pressure area on top and a low pressure area on the bottom. Air is forced down through the cooling fins of the cylinders, keeping them cool.

My fellow builders have mixed opinions, mostly to do with my lack of craftsmanship and a little "why didn't I do that" thrown in. The idea of cheating the seams and where the baffling meets the firewall with industrial aluminum ducting tape is sort of "smupid," in that it's both smart and stupid at the same time.

But nobody can tell me why it won't work, so I'm running with it. It's just way outside the normal conventions of doing it.

But hell, that's why they're called Experimental aircraft!

I don't see why the alu-duct tape is "smupid", at worst it's "smartd" (increased ratio of smart to stupid ).

I'll be interested to know if your dual-pressure theory works in practice. What aircraft have implemented such a desing?

My gut tells me that the upper area may not develop sufficient pressure relative to the bottom to work due to pressure leaks (how is the cowling sealed to the fuselage?) and, the horizontal separator may cause turbulence in the airflow around and past the cooling fins which may offset any benefits derived from the design. This is, of course, pure speculation. Outside of an proper airtunnel testing it is impossible to know how the design will work at different velocities and angles of attack.

Exciting stuff! Did you get all your electrical gremlins sorted out?

Well you will know after a few flights if your "smupid" idea has merit.


Wheels

Baffling like that is pretty much a mainstay of air cooled engines, either by a plenum (formed fiberglass that draws air in and forces it over and down between the cylinders) or by splitting the engine compartment with a baffle like I've done.

Here's another way to do it:

[img]http://eaaforums.org/attachment.php?attachmentid=5138&stc=1&d=1447162354[/img]

But most of the Nieuports do it as I've done it (though a little bit more sexy).

I'm going to put some felt around where the cowl fits the aircraft.

However, the idea here is to increase airflow over the cylinders; one wants as tight a seal as one can to the cowl and the firewall, but it's not like we're talking high pressure - just higher pressure. Plus I've got a huge oil cooler that holds about a quart of oil including the hoses to help out on that front.

I just got back from our monthly EAA meeting and the consensus was that it should work out okay, and if it doesn't it's easy to modify.

Angle of attack is a tiny consideration as all of this is right behind the prop and air is just getting rammed into the upper part of the cowl and there's nothing underneath.

On electrical - yeah, sorted. I wound up tying all grounds for the gauges together and running them back to the battery. The tach was replaced with a less attractive version, as the Royale tachs seems to be hit or miss with VW's.

Even with only 'higher pressure' one can get a build up of pressure on the high pressure side (semi stagnate air) if there is not enough air flow to the low pressure side.

Dude, that is waaaaay too professional looking! LOL! Mine would have a lot more false marks, cuts, wrinkles, and gaps in it than that.

Very, very nicely done.

You know, I spoke with both Robert Baslee and the guy up in Minnesota or something like that that built the Pup and their ideas sounded like exactly what you are doing, give or take some jots and tittles of personal design.

Purely out of curiosity, would some sort of scoop improve things right around the cooling fins. Not so much anymore, but some planes I flew were scoop city!




The other think I was just thinking about, and maybe this would only work in high altitude jobs, but has anyone ever used a fuel/oil heat exchanger on one of these? Like I said, the fuel might not be cold enough for it to work.

Anyway, your solution looks spectacular and, since it's easy enough to modify, doesn't mean that you'll be taking half the plane apart if it doesn't work.

Outstanding!

Deacon

I tend to fly rather low and slow, which a real life fighter pilot described as "loitering over the entirety of the route," which he did with a smile, having traded in F-104's and F-106's for a Champ.



On scoops: one of my early design ideas was exactly that, scoops that covered the tops of the cylinders and then went forward to the edge of the cowl. But it's just too complicated.

A little fun to reward myself for the work up to this point.

Things went pretty well, but I noticed a couple little things to correct.

Dart, I remember the first time I saw the thread where OG asked how your progress was, and you posted a picture of partial frame under a tarp in your backyard. I thought to myself "Hmmmm. Whatever dude."

But I'll be damned. Shame on me.

That video was fun to watch, not to mention the insane sense of pride you must feel taxiing that thing around. This thread is by far the most worth while one to check on SHQ. I check almost daily.

Keep up the good work!

Yay, Awesome!

Can't wait for the first flight, like an estimate 10K other people here.

Looking good Dart.....
You must of felt an immense feeling of satisfaction; taxiing the fruit of your labours on a nice sunny day. What could be better....except the first flight of course
I expected a little triumphant ejaculation at the end of it (A 'woohoo!', not the other kind!)

Be interesting to see your tally of total hours spent constructing when you finish the build.

Cool. That "documentary" made the craft look larger and the roar of the engine has a deep growl which also makes it seem bigger. I was expecting a high revving, screamer. very cool.

Getting close.


Wheels

Nice vid. Must be a real sense of accomplishment.

We were discussing "fast taxi" at the last EAA meeting and had a few chuckles.

Fast taxi is where one takes the aircraft up to almost flying and then slows it back down.

The advantages are that one can get a feel for stability of the aircraft, control response, and any other issues that can effect flight.

The disadvantage is that fast taxi can affect flight - if things get a bit squirrelly, the proper thing to do is increase power and take off. My one experience with a fast taxi attempt was in fact flight.

The chuckles came from my comments that I'll do a fast taxi attempt if the DAR hunt takes too long once she's done and then self report the flight and landing to the NASA site.

This is too cool!
At the end you wrote, "Still a lot left" - and I suppose that means, things that need to be done before the official check and first flight. What items still need to be done?

Are we there yet?