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Issue with Left Air Inlet Ramp

CharlieWaffles

CharlieWaffles

Well Known Member
I'm to the step where I need to cut the air ramps to clean the air inlets in the cowling and I am having an issue with the left ramp. I temporarily placed the 2" SCAT tube flange on top of the ramp to make the issue clearer in my photo. I see three options and problems:

1) If I cut the ramp back per the plans, it will cut into the location of the scat tube flange mount. So I would need to move it to the right.

2) If I move the SCAT tube hole to the right, then it would be buried under the conical side flange that will be installed between the ramp and the upright side baffle.

3) I could cut the cowl inlet itself shorter. Currently the inlet sizes are per plans (2" on the outer portion of the inlet, and 3.5" near the prop"). This may or may not necessitate removing the aft most nutplates near the flywheel.

Other ideas? Recommendations? FYI this is a stock setup for the RV-10 (IO-540, etc..)

90691ae7-ddcf-4749-a5df-de369cb91714_zpsa08182c5.jpg
 
CharlieWaffles said:
I'm to the step where I need to cut the air ramps to clean the air inlets in the cowling and I am having an issue with the left ramp. I temporarily placed the 2" SCAT tube flange on top of the ramp to make the issue clearer in my photo. I see three options and problems:

1) If I cut the ramp back per the plans, it will cut into the location of the scat tube flange mount. So I would need to move it to the right.

2) If I move the SCAT tube hole to the right, then it would be buried under the conical side flange that will be installed between the ramp and the upright side baffle.

3) I could cut the cowl inlet itself shorter. Currently the inlet sizes are per plans (2" on the outer portion of the inlet, and 3.5" near the prop"). This may or may not necessitate removing the aft most nutplates near the flywheel.

Other ideas? Recommendations? FYI this is a stock setup for the RV-10 (IO-540, etc..)

90691ae7-ddcf-4749-a5df-de369cb91714_zpsa08182c5.jpg
Click to expand...

Charlie,

As with the cabin top and doors, I think Van's recommended cut lines are just starting points. I cut the al. ramp back to within 1/4" of the hole, which eliminated one rivet hole. Then trimmed the aft edge of the fiberglass till I had a 3/8" gap between the 2 edges. If I was doing it again I would trim the fiberglass to leave more of a gap. It is very difficult, but not impossible, to pull the rubber gap seal in to place when reinstalling the lower cowl. A larger gap would make it easier.

Jim Berry
RV-10
 
I did not have to remove that fwd rivet, I left about 1/4" gap which was too tight. I have to use an ice pick or cotter pin puller to get rubber seal pulled up. Before you do your final install, you may want to cut both air dams down 1/2" to start. Several have removed them completely.
 
Mark,
It appears that your cowl inlet ramp is to deep. When I trimmed the inlet I ended up cutting the ramp all the way back to minimum distance for the forward rivet, I then cut the glass back to obtain a 1/2" gap. It's still a real pain to install the cowl. As Wayne stated, you have to use a screw driver or pick to pull the baffle seal over the top of the engine inlet ramp when you are installing the cowl. I would recommend at least 3/4" gap between the glass inlet and the engine ramp. Below is a photo of how far back I have the engine inlet trimmed. You should also think about eliminating or trimming the front cylinder dam. I ended up removing it completely and I think Tim Olson removed all but the last third. I added the only photo I could find of the cowl inlet

IMG_2512.jpg


IMG_2323.jpg
 
Last edited:
Bill, from the looks of the second picture your inlet is cut back enough that there are only two screws near the propeller area, is that correct or is it that just two of them are cleco'd?
 
The air dams on different -10s run the gamut from full height to none. I suggest installing them with nutplates instead of rivets, so they are easy to modify.

Jim Berry
RV-10
 
couple more pics

Nothing much to add here just what everyone said, trim more off the inlet ramp.

IMG_1481.JPG


IMG_1480.JPG


IMG_1658.JPG
 
No room

N15JB said:
The air dams on different -10s run the gamut from full height to none. I suggest installing them with nutplates instead of rivets, so they are easy to modify.

Jim Berry
RV-10
Click to expand...


Jim, it's a good idea but there isn't any room for the nutplates. The air dams are right up against the cylinders fins.

David
 
dhmoose said:
Jim, it's a good idea but there isn't any room for the nutplates. The air dams are right up against the cylinders fins.

David
Click to expand...

David,

The air dams attach to a piece of al. angle. Plenty of room to attach the angle with nutplates.

Jim Berry
RV-10
 
Food for thought...can we get a pole of how many people with 2" holes have ever opened their heat knobs past 1/2 way? I usually drill a 1" hole for the heat and then you can put the scat flange wherever you need to while still covering the hole. I have never much more than cracked the heat knob, even in my small amount of up north winter flights. Also gives more engine cooling air for those hot days.
 
I used the two inch heat inlet but my flexible baffling covers about the forward third. Plenty of heat but I do live in northern CA.

I wonder if there is a minimum flow requirement to keep the heat exchangers or mufflers from overheating?
 
My 2" flange up front is covered with a cap, unused.
I decided to install 2 side by side flanges on the upper right side of
The rear baffle. I hardly ever use heat and if I do it's a crack open at most.
A one inch hole would have been plenty big for my heating requirements.
 
I had a similar issue. I trimmed the front corner from the scat flange and then fitted a rivet slightly to one side. I also had to make a slight "half-moon" cut in the cowl-to-ramp seal to clear the opening.

My whole cowl seems to be a bit shorter than intended by VANS, even though I have a stock engine. It may be due to the depth of the MT prop spinner requiring the cowl to be slightly further aft than with the Hartzell.
 
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