Air ramp problems

From the picture is hard to see but the the left hand side air ramp is 1/2" higher than the bottom cowl. It's from Vans baffle kit and the air ramp is pre-drilled to the cylinder 2 baffle so it can't be a builder fabrication problem.

If I attach the rubber airseal on at this stage there will be a distinct "step" which of course is not right. Has anyone come across this situation before and what was the fix, does the cowl inlet need to be trimmed back ?



Thanks in anticpation


Martin

Can't really tell from the pic but your suppose to have a bend in that part that matches up to the cowl inlet.

Looks like this one has been cut off???

Pic below belongs to Jeff:

Yeah, it's definitely too high

...so something hasn't been done correctly. Both the -6 and -7 and probably the-9's all have a diagonal bend across the lower ramp and it's usually slightly lower than the inlets.

Best,

Looks like the baffle is flat. There should be the diagonal bend starting from the outboard edge of the cylinder to the forward edge of the baffle near the prop. That bend creates a slope which will line up to the inlet.

Roberta

wish it was

Thanks fellas but it's not that simple, this is the horiz induction so does not have the "kink" in the ramp that the pictures you are showing does. The ramp position is predetermined by the support bolts. I can't figure out why this has come about and was hoping someone with the same setup might throw some light onto it. I'll keep plugging away, I'm sure I'll find the problem.

Thanks

Martin

That is the right approach

Several things in the area forward of the firewall on my RV-6A were not right and I just had to back off and decide the best way to fix the problem as you are doing now. It is good to suspect that you have done something wrong if something isn't right and spend some brain time trying to figure it out but after a few of these impossible situations you realize that some things from Vans are not right as they come out of the box, especially when they have to work with a tremendous range of variables in engine installations.

The basic thing here is, the inlet ramp must be below the lower cowl cooling air inlet opening. What is the best way to handle that problem. Like I said, I ran into many conflicts like the nose landing gear strut extending through the space required for the FAB (filter air box). I cut a hole in the FAB in the form of a plane parallel to the strut and fiberglassed a new FAB wall to close the box and provide enough space for the box to clear the strut during operations. The engine control support brackets were good material to work with to fabricate the brackets needed - nothing more.

The thing that surprised me most was the the amount of twist I had to add to the left wing incidence to get it right before drilling the rear spar to fuselage attach hole.

Bob Axsom

shiney said:

Thanks fellas but it's not that simple, this is the horiz induction so does not have the "kink" in the ramp that the pictures you are showing does. The ramp position is predetermined by the support bolts. I can't figure out why this has come about and was hoping someone with the same setup might throw some light onto it. I'll keep plugging away, I'm sure I'll find the problem.

Thanks

Martin

Click to expand...

How old is the baffle kit and is it for that engine?

It sure looks like it doesn't belong in that airplane or it is a piece in the wrong place. It won't work the way it is.

my point exactly!

How old is the baffle kit and is it for that engine?

It sure looks like it doesn't belong in that airplane or it is a piece in the wrong place. It won't work the way it is.

Click to expand...

That's the conclussion I'm coming to! I got the baffle kit with the FF kit and suspect it's the wrong ramp, I've emailed Vans and will let you know the outcome.

Thanks

Martin

Can you post a picture with the cowl off? I am working in this same piece of the baffles right now, and mine (from the new baffle kit) has a downward bend pre-formed in it.

Also, I am realizing that the baffles become somewhat easier if you only use the plans as a general guide to accomplishing the objectives, and work out the individual details on your own! I went out to the airport and stuck my hand in the cowl of five different RV's this weekend to feel how the inlet ramps were constructed, and not one of them was the same as the next. One of them didn't even have any rubber seals between the baffles and cowling!

good luck,
mcb

Hi all,

The only issue I had during flight testing was an extreme vibration that had possible causes such as out of balance prop, engine issue (serious) or dodgy mounts.

It turned out to be the rubber baffle flapping on the ramps. So I cut the baffle rubber down to less that 1/2" and all was better. I too had stuck my hand in the inlets of other RVs and found some with none. I feel that the baffles in this area is not so important as the baffling within the cowl.

Don't forget to seal the ends of your top cowl fibreglass ramps...

Horizontal Air Filter Bracket

Here is a picture of mine under construction. I made mine so the left side was just under the bottom cowl to allow room for the rubber seal. This makes the right side a little lower than the bottom cowl, but the rubber seals it pretty well.

http://yfrog.com/jyairfilterbracketsj Picture