Baffle(ing) Question

Henryrifle · #1 03-03-2015, 01:47 PM

My O-320 equipped fixed pitch RV-6 has relatively new baffling. It is the Vans kit. The rubber baffling at the back of the engine, the one parallel with the firewall, continues to curl backward toward the firewall in-flight. I believe this is impacting engine cooling as my oil cooler is firewall mounted. What are some sensible ways to resolve this issue?

Should I remove the rubber part, extend the aluminum baffling by a half inch or so and then reattach the rubber part in hopes of making it more resistant to flipping back? Is there a thicker or stiffer rubber baffling material that would be more resistant to the pressure?

Thanks in advance for your thoughts,
Hank

bruceh · #2 03-03-2015, 01:56 PM

How much space is there between the cowling and the aluminum baffle?
A half inch is recommended. If it is much more than than, then I would pop rivet on some extensions to the aluminum.

You might also try to put in wider rubber.

Henryrifle · #3 03-03-2015, 02:00 PM

Bruce,

I'll have to measure to know the answer for sure but I would say that it is more than 1/2". Thanks for the advice and I'll measure next time I am out there.

Thanks again,
Hank

JonJay · #4 03-03-2015, 02:40 PM

One thing you might be able to try. Form the material with your hand at the corners and tie the back to the side with lacing cord with it folded into shape. This only takes a couple of stitches near the top of the fabric. Do the same at each split in the back. Don't get too crazy and fold over too much or it will not seal.
If that works, over time, it will take that shape and not want to be blown back. This will only work if your spacing is marginal, not if it is way to large.

az_gila · #5 03-03-2015, 03:49 PM

You could also gently bend the top 1/2 inch or so of the baffle metal - where the rubber is riveted - forward about 20 degrees or so.

This will help the rubber lay forwards when the top cowling is installed.

Jesse · #6 03-04-2015, 06:06 AM

If you are sure the baffle seal is laying correctly when you put the top cowl on, then it is actually being blown back in flight, then your gap is way too big or the seal is way too short. You could extend your baffle aluminum, even without moving the rubber seal, or you could buy some thicker and stiffer baffle seal. Aircraft Spruce sells silicon baffle seal in rolls in different thicknesses.

Henryrifle · #7 03-09-2015, 06:51 AM

Jon:

I have tried your suggestion an after one relatively long flight, it has worked! I'll keep an eye on it but happy to learn about a simple solution.

Thank you all for the education and ideas,
Hank

JonJay · #8 03-09-2015, 11:57 AM

Quote:

Originally Posted by Henryrifle

Jon:

I have tried your suggestion an after one relatively long flight, it has worked! I'll keep an eye on it but happy to learn about a simple solution.

Thank you all for the education and ideas,
Hank

Excellent. After a few hours you will be able to tell if it is sealing well by the witness marks from the baffle material on your cowling. If it is blowing by, you will see it. Glad it worked.