RV7A Flyer

RV7A Flyer

Well Known Member
Patron
Experimenting with a little aluminum foil tape to find the right heights for the air dams before cutting them down and installing them (made mine removable), and found 1/2" results in a difference in CHTs of about 10 deg F between front and rear cylinders in level cruise at normal speeds. This is in comparison to 25-30 deg difference without the tape. The only issue with this is that the front ones tend to get a bit hotter during initial climb (just over 400, unless I shallow out the climb considerably, or step climb, either of which is manageable).

What would you consider a realistic goal for getting the temps matched up? 5 deg? 0? :) I.e., how much "polishing the cannonball" should I do here?

TIA!
 
I'd be quite happy with a 10 degree delta, for me I see about 30-35 delta in a hard climb and about 20 delta in cruise with the front cylinders cooler.
 
How much of the original air dam are you guys flying with, trying to decide if I need to trim some before first flight?
 
bret said:
How much of the original air dam are you guys flying with, trying to decide if I need to trim some before first flight?
Click to expand...

I put them on for the first flight, and took them off immediately after...much, much too large, blocking too much airflow to the front cylinders.

I haven't had them on now for 400+ hours, but decided to start messing with this a few weeks ago.

I'd leave them off entirely for the first flight and see what you get. And, one of the best pieces of advice I got during the build...make them removable, with screws and platenuts, NOT riveted in!
 
I pulled mine, but after getting everything sorted out and broken in, I could probably use a small dam for my #1 jug.

Larry
 
You must log in or register to reply here.