Kyle Boatright
Well Known Member
The RV-10 remains a work in progress. It is fully functional, but there are probably 20 things I'd like to do to refine/optimize the airplane and I've been picking those off one at a time.
Anyway, on a trip to Florida about 6 weeks ago, a buddy and I identified several air leaks associated with the doors and cabin top. There were leaks into the cabin (from the NACA duct fed cabin top plenum) around the strut mounts. It was amazing how much (cold) air was flowing into the cabin through a couple of 1/2" square openings. That's an easy fix - I just need to pull the access panel and glue a little piece of baffle seal over each of the holes.
The other notable leaks were from air exiting the cabin at all 4 hinge pockets. My airplane has excellent door seals...except at the hinge pockets where I never addressed the issue. The exterior of the cabin is convex at that point, and there is almost certainly a low pressure area in the vicinity of the hinges, which creates a noticeable pressure delta.
So there I was the other day climbing up high to do some economy testing and I thought to cover 1 of the 4 hinge pocket openings with my hand. I was surprised at the apparent pressure delta - it really sucked my hand down (up?) firmly against the opening. But I was more surprised at the difference covering that one leak made in cabin noise. Wow. I'd have never guessed. So now, hinge pocket covers are much higher on my improvement list than before. This will be a multi-faceted improvement. When I eliminate the leaks, I'll get less noise, better heat in the winter and should see a modest performance improvement since I'll be eliminating excrescence drag, which is drag caused by air leaking out of the airplane into the slipstream. Excrescence. Say it. Spell it. Use it in a sentence. Oh, and here's a link to a 172 page paper on it:
https://apps.dtic.mil/sti/pdfs/ADA106030.pdf
If DanH sees this, he'll probably stay up all night reading...
Anyway, on a trip to Florida about 6 weeks ago, a buddy and I identified several air leaks associated with the doors and cabin top. There were leaks into the cabin (from the NACA duct fed cabin top plenum) around the strut mounts. It was amazing how much (cold) air was flowing into the cabin through a couple of 1/2" square openings. That's an easy fix - I just need to pull the access panel and glue a little piece of baffle seal over each of the holes.
The other notable leaks were from air exiting the cabin at all 4 hinge pockets. My airplane has excellent door seals...except at the hinge pockets where I never addressed the issue. The exterior of the cabin is convex at that point, and there is almost certainly a low pressure area in the vicinity of the hinges, which creates a noticeable pressure delta.
So there I was the other day climbing up high to do some economy testing and I thought to cover 1 of the 4 hinge pocket openings with my hand. I was surprised at the apparent pressure delta - it really sucked my hand down (up?) firmly against the opening. But I was more surprised at the difference covering that one leak made in cabin noise. Wow. I'd have never guessed. So now, hinge pocket covers are much higher on my improvement list than before. This will be a multi-faceted improvement. When I eliminate the leaks, I'll get less noise, better heat in the winter and should see a modest performance improvement since I'll be eliminating excrescence drag, which is drag caused by air leaking out of the airplane into the slipstream. Excrescence. Say it. Spell it. Use it in a sentence. Oh, and here's a link to a 172 page paper on it:
https://apps.dtic.mil/sti/pdfs/ADA106030.pdf
If DanH sees this, he'll probably stay up all night reading...
