Hey guys, i need some help with constructing baffling to cool the engine in a 33% Extra with a ZDZ-100 in it. I've been flying 50 size planes, so I never had to build any. I get the general idea behind it that you want to force the air through the fins, but would still appreciate any help or some pics. Tis particual cowl is a two piece that splits about 1" above the thrust line. My general questions are what is the best material to use, how do you attach it to the cowl, and how far back over the engine do you go?

Thanks

Mike

Here is a good article on baffling.

http://www.cactusaviation.com/Tech/baffling.html

I recently tried something- used on full scale EXTRAS-and it works .
We did a WH35% with a ZDZ160 and JMB cans -which fit close to bottom of engine on 5"headers . (absolute rocket!)
This really blocks air flow out the bottom -so----------
I copied the fake louvers in the kit cowl-- and simply put them on top edges of cowl- I used 3 cutoff discs stacked to make the 1.25" long slits- 13 of em in a row
Having seen how well it eliminates the trapped air in the top of the cowl-- I am going to REALLY do up the cowl on my new super snorter Giles 202 with a Super Snorter ZDZ80 single and pipe .
Old hot rodders will recall the multi louver rows on '32 Ford hoods (and '40's)
I found that the best place is at rear corners on EXTRA and on the round cowls - It should work equally well. there are lots of em on a YAK
For those who can't cut holes in cowls -
drill big round ones - not purty but it will get airflow over top of cyls and out the rear of the cowl
Anybody else used this setup?