Comment

Comment by Mark Gravatt on December 10, 2012 at 3:25pm

Louis,

Yes, it helps a lot.  As I am just getting started, I am trying to complete the build in my mind so that there are as few changes to the configuration (during actual building) as possible.  I don't want to be re-fabricating parts because I didn't see something that I preferred to do until after the fact...

Thanks for documenting this.  I have always liked the LoPresti cowlings with their two round holes.  Reading your logic, this configuration seems to maximize cooling airflow.  Thirty six years of flying (off and on) and still another aha moment for me!

Comment by Louis W. Ott on December 9, 2012 at 10:39pm

Hi Mark,

I took a few pictures of the cowling at the hangar today. I am soooo close to finishing this airplane, but there always seems to be one more thing.

I think the cowling on the plane looks really good and not like most other Corvair installations.

Hope this helps.

The first picture shows the top of the engine and that it is quite a bit different than the usual Corvair. My starter is in the rear so I don't need the height in the front for the starter. My carb (Rotec) is where the distributor normally fits. My cold air intake is along the right rear of the plenum area. The intake manifold is on top of the engine.

This picture is of the plenum cover over the top of the engine. This fits tight under the cowling top.

The next picture shows looking in the air intake right above the cylinders and heads. No turns or other impediment to air flow.

Next couple of pictures shows the cowling on. It isn't fastened down just sitting on top. Paint is primer to keep the oil and dirt from getting into the fiberglass.

Comment by Louis W. Ott on December 7, 2012 at 11:49pm

Hi Mark,

The cowling has worked out nicely... so far. It looks great. The ground run engine temps have been quite cool I think. The outside temp is only about 50F so I don't know what will happen at 100+F. Now, I can run it wide open for as long as I want and the cyl head temps don't go above 300F. Temp probes are under the spark plugs. The air intakes located up high lets you make a decent straight in diverging inlet to the cooling plenum. The inlet isn't as long as it should be for best efficiency but is a lot better than other nose bowls with inlets centered about on the crankshaft. Then, the air usually hits a flat plate in front of the cylinders and has to turn sharply and go up to get to the top side of the heads. That presents quite an energy loss.

I notice that I don't have any frontal pictures after it was mounted on the airplane. I'll take a couple tomorrow so you can see. The airplane is at the airport now with almost all work finished. I expect that it will be ready to fly by year's end.

Comment by Mark Gravatt on December 7, 2012 at 8:56pm

I like this a lot.  Nothing against the standard 'Vair cowling, but this looks nicer, IMHO.  Some day I hope to retire in Arizona, and I am planning everything to accommodate operations in temperatures up to 120 Deg. F.  That makes me wonder about the air inlet sizes of all cowlings.  Next time I am down there, I'm going to try to meet up with a couple local ZZ builders and get their input.  It is not uncommon to see 100+ F around here in Nor Cal central valley in summer.

Keep those pictures coming!  Thanks...