James inlet ring to Vans FAB interface

I am about to begin work on the FAB for my carbed O-320 but I don't have a clear understanding of the interface from Sam James inlet ring to Vans FAB. My research hasn't thrown up an answer.

In particular, I can't see how you can get a satisfactory seal while still allowing the lower cowl to move straight up and down for fitting and removal. At most, the cowl can move forward 1/4in before it hits the aft edge of the spinner so vertical movement is really the only option.

James supplied an "induction adapter" piece that goes from circular to D shaped but the instructions say that it should be bonded to the FAB, meaning the sealing takes place at the forward end behind the inlet ring by means of a flexible sleeve. But how can you insert the FAB end into this seal when you have no horizontal freedom of movement?

Does anybody have any pictures from this area of a similar project?

Loman,

Originally I had a flexible sleeve of baffle material attached to the aft edge of my cowl air inlet, and as you have surmised, it was a hassle to get it over the forward edge of the fab. I switched to a method I borrowed from someone on the list that works much better.

It consists of 2 overlapping half round pieces of baffle material; the top half fastens to the forward edge of the fab and extends forward 3". The second piece fastens to the aft edge of the cowl inlet and extends 3' aft. Makes it easy to move the lower cowl vertically. I had some concern that I would have inlet air leakage between the 2 pieces, but there is no detectable change in MP or airspeed.

Jim Berry
RV-10

Sam James inlet

I use a short section of scat from the inlet to the airbox. A rubber or neoprene sleeve may be a better option, the scat is a tight fit.

You didn't say if you have the short or long cowl.

On my -9, I have the short cowl, which has less room than the long cowl.

I had to significantly modify my FAB as the transition piece provided by Sam James wouldn't work with a carb. It is my understanding, and I could well be wrong, that the short cowl was set up for a fuel injection servo and not a carb.

Here are some pictures of the FAB modification I made.

To transition between my FAB and the inlet I simply used some of the wetsuit material provided for the cooling air inlets.