B-model cooling exits

[Area 51%]

Can someone give the dimensions and location of the cooling air exit holes on the B-model cowl? I'm about to try something else in the same location on a Legacy, but don't want to make my exits so large (or odd shaped) that the Bs vents won't fit if this experiment goes wrong.

[WesRagle]

Hey Randy,

You have probably seen this but, if not, it might help some.: https://www.sonexaircraft.com/documents/plan_sheets/SNB-P16-06_NC_B-Model_Cowl_Vents.pdf.

Wes

[GraemeSmith]

Randy:

I did post this - but have to stress that I posted it April 1st (some people missed that)
viewtopic.php?f=3&t=6159

Here are the "B style" vents I DID put in a Legacy cowl:

Mold made of waxed pine board

Lay up of epoxy and glass, aluminum tube to reinforce edge and curing under peel ply

Section after releasing from mold

Trimmed and epoxied in place over slot in cowl

Aluminum end plates epoxied in place

Outside - priming and filling

In Service - ignore crappy cowl paint.

I was trying this before I tried an opening cowl flap in the bottom of the cowl. Slots were a lot of work for a small gain. Wish I had tried a cowl flap first. I suspect it will be a lot more effective and can be stowed to streamline when not needed. That's next and I may even remove the B Vents if the cowl flap works better.

[Bryan Cotton]

That looks a lot different.

[Area 51%]

Thanks Wes, that's what I was looking for.

Graeme, it appears at one time there was another opening below your vertical vent. As I recall, the April Fools post showed what looked like marine vents. The witness marks under your B-ish vent looks to be just that.

What I have in hand are the Van's supplemental vents that, according to the installation sheet, get installed in the bottom of the lower cowl ahead of the normal opening in an RV. My intention is to install them in the sides where the B-vents will go if this turns out to be a bust. They are multiple gills as opposed to a single slot.

Thanks Group.

Wishing in one hand and shi--ing in the other here @Area 51%

[Kai]

I posted this on the actual flying Rotax thread as well.

The side outlets for my Legacy were more or less shaped according to a drawing that Kerry mailed a while back. Let me just say that in addition to the standard bottom exits, the improvement in cooling efficiency with the addition of the side outlets is massive!

Thanks
Kai