Cooling Schemes

[swinn]

For those of you who are flying air cooled engines, I am reasearching the various cooling options for the Long-EZ. Not really intersted in the 'P-51' scoop is an option. Our Long is getting a 200HP IO 360, so we are expecting cooling to be more of a concern than usual and trying to weigh the benefits/pitfalls of each setup.

 

The options seem to be armpit scoops, belly mounted naca scoop, or shoulder scoops. Then there is the choice of updraft or downdraft. I've heard of exhaust augmentation, but I'm not sure what that means.

 

I have talked to the owners of two armpit scoop setups. Both of these are smaller engines, one an O-320 and the other an O-235. Both have oil cooling problems which they are still trying to work out. Both aircraft are updraft cooling.

 

Another owner had a belly mounted NACA scoop which seemed to be working OK with his O-235. The oil cooling was reported as acceptable - this was accomplished with some extra venting in the rear of the cowl to exit the oil cooler air.

 

I'm interested in hearing from people who are flying air cooled engines on EZ Types (Long, vari, cozy, etc...). What setup do you have and is it working? Where is your oil cooler and how are you getting air into/out of it. What type of oil cooler are you using? What temps are you seeing?

[unick3]

Hi,

I installed drown draft cooling in my longez with scoops on the upper cowls. I found it works extremely well. I used to have an O235 with a P51 type scoop and the cooling was marginal with great oil cooling. Now I have terrific 'out of the box', no mod engine cooling and marginal oil cooling (I am working on that). Overall, I would most certainly recommend down draft cooling for any of the canards.

 

The issue is how do you accomplish it. Arm pits, NACA, external scoops? Who knows. For the LongEz's it is easiest accomplished with external scoops. Cant speak for the Cozy’s, but I would suspect NACA style scoops.

 

I strongly believe in exhaust eductors. My plane has a rough approximation. Again, there is no hard fast rules, formulas, techniques for how it is accomplished. I cut, chopped and spent lots of time trying to figure out what went wrong.

 

Unfortunately, this IS experimental aviation, and experimenting comes with a cost...time. Lots of time sent on trial and error.... I spent 7 months doing a 2 week engine replacement because I wanted to experiment. I am happy now, but 4 months into the project I most certainly was not…

 

I would just recommend, hanging out, learning, going to air shows, and see what is currently working for people. You'll have LOTS of time to soak it all in and make intelligent decision on how you want to spend your time building... either quick or innovative (long).

[swinn]

Thanks for the information Nick. Actually we are nearly ready to start fabricating the cowling. The engine mount should be here in about 3 or 4 weeks and I've already started mounting accessories. I have heard good things about downdraft cooling with shoulder scoops from several sources now. Do you have any photos you can share of your Long EZ downdraft install?