Basic cooling plenums built

[n3480h1]

After cutting up several sheets of heavy card stock, and finally some aluminum, I now have the basic plenums built. This is my first experience at forming aluminum, so be kind. There is more detail work to do. And I have questions. Should I add a small deflector at the lower front of each front cylinder to help direct the air up and over the cylinders, to cause it to be forced down through the fins of all four? I suspect that if I leave it as it is I will run cool on the front two and hot on the rear two.

Silicone baffling material and exhaust wrap will arrive Thursday. I have two 1" blast tubes coming off the back of the plenums - one for scat tube to the mag and one for the gascolator. Comments and suggestions are appreciated.

Tom

 

[splischke]

I assume you checked that your plenums have adequate clearance to the upper cowl - ? I had to design my plenums so that they angle downward.

 

[eschrom]

You do nice work, Tom, but ditto about Scott's concern. I'm pretty sure your baffles would not fit under my cowl.

Ed

 

[n3480h1]

Yep, I worried about that before starting, and during building, but with a little planning and a lot of measuring, they do fit under the cowl. I don't have a pic, but I mounted the cowl before and after the plenums were built. The prop hub is centered in the cowl vertically and horizontally, and extends 3/8" from the front of the cowl. I have 1/2" clearance at the back corner of the plenums and 3/8" at the highest points toward the front of the plenums. The thing I don't know is just how much the engine will move on its mounts. If its more than 3/8" vertically, I will have to modify the plenum sides and make new top plates.

Another factor in the measuring was that I plan to do taxi work with the engine in its current 1915cc configuration (no flight), with the hub shown. As it is set up, I will need to use a 1" spacer between the hub and the prop to accomodate the 1" backset for the rear spinner bulkhead. Then the engine will be pulled and sent in for the stroker crank, to bring it up to 2276CC with the Force One prop hub - which is 1" longer - so the spacer can be eliminated. I know that's a lot of screwing around, but the crank conversion will run about $2500 and it takes a while to save up that much while continuing on the airframe and wings. The one possible Plan B is that I may just go with a new 2276 from GPASC and move the 1915 as is . . . into the biplane build.

Tom

 

[splischke]

3/8" clearance is enough at this location. The engine, despite the Lycoming rubber mounts, doesn't move around much. My spinner is 1/4" from the cowl and it never rubbed even when running on 3 cylinders ;D

 

[n3480h1]

Ah ha ha . I had thought about performing a worst case experiment by cutting the ignition to one cylinder to see just how much it would jump around. Very good information, Scott. Thank you.

Tom

 

[splischke]

I'd like to say it was a planned experiment but actually it wasn't. It happened when the #3 auto-spark plug adapter vibrated far enough off the plug. After that, I switched back to aviation plugs but at $41 a pop, I may go back to auto adapters and look for a way to secure them better than with a single 10-32 set screw. I also found that the phenolic component of the adapter loosens with time and exposure to operating temperatures. My last set hardly grabbed onto the ridges of the plugs. Yep, double trouble -- the aluminum can slip off the phenolic and the phenolic can slip off the plug. Anyone else experience these issues? I'll split the thread if replies are made.

-Scott

 

[phzabriskie]

You do nice work, Tom, but ditto about Scott's concern. I'm pretty sure your baffles would not fit under my cowl.

Ed

10-4 Tom very nice work... I tried to get a bunch of kids in shop class here 1st day of school excited about airplane building but the all look back at me like they were all starting the worst prison sentence anyone ever faced.

 

[n3480h1]

Thanks for the nice comments, but the best laid plans . . .
Turns out I bought a used fuel tank which fits ok but leaves no wiggle room. That, and the oil cooler blast tubes hold the top cowl up at the nose, about 1/4" from where it needs to be. The tank by itself is not a problem but the blast tubes are the real issue. So, its on to Plan B, which will require reconfiguring to something more like Scott's setup.

In the meantime, a friend has offered a partnership with very favorable terms in an Ed Fisher designed Skylite ultralite - an offer I could not refuse. So, I will have something to fly while I continue to build the Sonerai. Its an ultralite that looks more like an airplane - really a remarkable piece of engineering. Should be fun.

Tom

 

[Raceair]

Tom....You got my attention....Do you know the Skylite's original builders name, or the serial #?...With either piece of info I can look it up and possibly find out more about it....I welded up a couple fuselages that went to Iowa......Ed Fisher

 

[n3480h1]

Ed, I do not have that information yet. But, I do know the last owners were two guys in Nebraska, in the Nat'l Guard. The plane is painted gray with Guard markings and has a Kawasaki 440 in it. But we can make it pretty again. I'll get the info and pass it along to you. Very nice design, Ed.

Tom

 

[Raceair]

Tom...Thanks for the compliments.. Ed

 

[phzabriskie]

Hey Tom, just want to compliment a few nice touchs. The oil breather return line is neatly done, and I found the Rustoleum superduper hightemp exhaust paint you mentioned and will give it a try as it looks very good on your straight pipes.
-Pete

 

[n3480h1]

Thanks Pete. The Rustoleum does look good, but be aware that it needs to be baked on. Directions and options are printed on the can. It can also be "baked" when on the engine. The oil return line is pretty neat, but I can't take credit - the previous engine owner fabbed that part.

Spent most of today entertaining lookers at the hangar. Hard to get much done when I have to be polite and use civil language, lol. Spent the last two hours touring a large scale RC aircraft factory nearby. Neat stuff. Best part of the day was putting my 19 month old granddaughter in the seat of the Sonerai. She did not want to get out. Her Dad's going to have a financial hit when she turns 16 and wants to fly her own.

Tom

 

[n3480h1]

Got out to the hangar at 4:00 a.m. this morning to avoid the lookers and the heat. It quickly got hot enough that no sane person would come out to the hangar, but I managed to get my plenums rebuilt - with the angle off the top of the intakes. Also managed to get the oil cooler blast tubes relocated so that they do not interfere with the top cowl, so now the cowl clears everything and the front edge is located so the spinner will be centered on the cowl. And it only took 12 hours. : Repositioned the panel mounts to provide better clearance between the instrument fittings and the back of the fuel tank. Too hot and tired to take the pics today, but will post some later.

Tom

 

[phzabriskie]

Very very ambitious engery level you have Tom. Send some of your coffee this way. See Spring~Summer ~Fall Thread for my progress.

 

[n3480h1]

Pete, there's a thin line between ambition . . . and desperation. I can spend a lot of time building the plane because its just me and Inspector Dog, and I'm basically a hermit.

Yesterday's effort -aside from putting the wings back on the Skylite - involved separating the canopy from the skirt, glassing in the NACA cabin ventilation scoops and further correction of the exterior lines near the front of the skirt. Today will see blending in the exterior junctions of the NACA scoops, filling and fairing every other screw hole (way too many made earlier), and work to smooth the canopy latching function.

Tom

 

[phzabriskie]

Pete, there's a thin line between ambition . . . and desperation. I can spend a lot of time building the plane because its just me and Inspector Dog, and I'm basically a hermit.

Yesterday's effort -aside from putting the wings back on the Skylite - involved separating the canopy from the skirt, glassing in the NACA cabin ventilation scoops and further correction of the exterior lines near the front of the skirt. Today will see blending in the exterior junctions of the NACA scoops, filling and fairing every other screw hole (way too many made earlier), and work to smooth the canopy latching function.

Tom

I'm gonna have to move west of the missouri river and get me some desperation.....but after winter.