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Baffles and Inlets

JDA_BTR

Well Known Member
I did my inlets and the baffles there strictly according to the plans. Now that cylinder 2 is getting cooling, next thing I want to do is perfect the inlet (reasonably).

I think on both sides that I'm not sealing completely when the upper cowl is installed. The rubber of the lower cowl is in good position though.

What I think is happening is that the upper cowl comes down, and there is a bit of seal at the most forward point, that ends up behind the lower cowl and can be pushed out and away from the inlet sending air to the lower part of the cowling.

When I pull the gasket material inboard so that it is in the center of the inlet and not lying behind the lower cowl edge it isn't laying well and it seems I would have to trim the gasket back some to make it fit better.

I think that the upper cowl inlet ramp may need some mods to make a better inlet.

Has anyone made mods to the inlet to get a better seal? I'm thinking of taping it over for a test flight to see if it makes a difference.
 
I re-made the front baffle seals that attach to the lower cowling - I reshaped them and made them a bit longer to give a bit more overlap over upper cowling. I used the original Van's seals as a template and some new baffle material from Spruce - seals better now. I did have a problem with the left front seal (on lower cowling) wanting to slide under the ramp leading to the air filter and this cured the problem. But I never saw any issues with CHT's being high - I just wanted better overlap and to fully close any gaps. My CHT's were imbalanced front-to back (1 and 2 were warmer than 3 and 4) - much better after removing the left front air dam and cutting right one down by about 50%.
 
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Is the purpose of the air dams to protect from incoming debris, or mainly airflow? On the left it protects the fuel inlet line too.
 
My CHT temp delta is about 12-15 between the hottest and coolest with #3, then #4 being the coolest and they run in the 320-330 range in cruise and in the 290-305 when LOP. My aim is to see if I can lower the delta by possibly cutting the air dam a bit.

I will be doing a oil change today, if you like I can send you pictures of mine. I believe mine seal well. I can't post pictures easily but be happy to mail them.
If you have iphone, we could possibly even do face time so you look at it at different angles.
 
Turner,

I am interested in seeing your cowl ramp mods. Are photos available?

Not really a ramp mod - just re-cut the baffle material to fit a little better. I did remove the air dam on front left, and cut the front right down by half. I'll try to get photos next time I'm in the hangar.
 
Turner, my bad - I read dam and thought ramp in your previous message. Got it. Yes, I would like to see what you have done.

Thanks
 
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