Center Baffle and inlet faring

[704CH]

I know there are lots of questions and lots of threads on baffling, but I couldn't find an answer to this specific one..

My question is about the center baffle and top cowl inlet faring junction.

Do you cut the baffle down, or do you space the faring so it clears the baffle?

From the pics that I have seen, most of you must be cutting the farings so that they clear the center baffle, rather than cutting down the baffle? In this case, how does the rubber lining work and keep it pressurized?

Can anyone post specific pics of this area or provide any details on the best path?

Thanks

 

[scsmith]

both approaches can work

Most of the baffles I've seen leak in that area.

If you want the baffle to be cut to fit the inlet ramps in the top of the cowl, the issue is that the baffle turns 45 degrees and angles toward the center of the engine, then joins the part of the baffle that straddles the nose of engine behind the spinner.
At some point, that 45-degree portion steps off the side of the inlet ramp, and that is a problem area. After scratching my head for many hours, I built a fiberglass transition surface between the inboard edge of the inlet ramp and the top of the cowl. I made it out of flat segments of foam glued together, then glassed over. So my baffles are cut to mate to this transition surface. It is a bit of a complicated shape, but one that allows the rubber seal to conform to the shape and seal. With all other aspects of my cowl and baffles stock, my CHT's are 270--290F at 2400/24".

The other approach that can be made to work well, probably easier than what I did, is to trim the intake ramp so that the baffle never touches it - the forward baffle fits to the original cowl surface everywhere. Now, you must be sure that there is no flow path around the inboard edge of the inlet ramp, then outboard to the other edge of the inlet ramp, and then dump air into an area that is outside the outer side baffles. So what most people do is close off the end(s) of the inlet ramps.

Hope that helps.

 

[vlittle]

Look at this thread

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