N941WR

N941WR

Legacy Member
Bob,

Today I had the honor of helping a friend unload his -7 QB. The guy who is building was a former race car driver and he is looking for ways to get every last knot of speed out of his plane.

He was thinking of modifying the NACA vents so they close flush.

Here is the question, have you tried making a plug for the vents to see if there is any speed gain there?
 
N941WR said:
Bob,

Today I had the honor of helping a friend unload his -7 QB. The guy who is building was a former race car driver and he is looking for ways to get every last knot of speed out of his plane.

He was thinking of modifying the NACA vents so they close flush.

Here is the question, have you tried making a plug for the vents to see if there is any speed gain there?
Click to expand...

Didn't AJ decrease the size of the cooling ducts on his RV6? I believe it's a fast plane.

Cam
 
No I haven't but ...

The NACA vents have not escaped my attention either. I have thought of race plugs and I have seen them taped over for races. I race with a teammate that I have been married to for 40+ years and sometimes like the 2005 AirVenture Cup race the heat is so intense that I have to crack the vent for her (well OK, me too) a little bit. However, I plan on doing it for cool day races. The implementation could be a plug or a cover but either way it is a good idea. I can visually and repeatably verify the impact of those "low drag" vents by opening and closing the metal vents I bought to replace the leaky plastic ones. The AirVenture Cup Race this year is from Mitchell South Dakota - maybe it will be cooler up there? Tell your friend I wish him good luck in the elusive chase, it can be very rewarding to the soul.

Bob Axsom
 
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Yep...

....they are seen on the faster RV's. I met a guy at Sun 'n Fun who said it helped on his -8.

AJ has one of the fastest RV's and had a bunch of under-cowl pictures of his 4 into 1 exhaust and extended exit area, also rounded.

I'd have to go with a Sam James plenum and intakes for max speed....also a TD config for sure.

Regards,
 
I did finally develop plugs for the NACA vents

I did finally develop plugs for the NACA vents in 2010 and posted the information in another thread. I had forgotten about this one. The speed gain on our RV-6A was 0.9 kts using my standard test method at 6,000 ft density altitude.

Bob Axsom
 
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