[g zero]

Any documented speed gains from taping over the Naca scoops feeding the cockpit inlet air ? My 8 has two , one on the left side of the fuselage on one under the right wing .

 

[David Paule]

What are you doing for a cabin air exit? Or are you letting it go out any gap it chooses?

Dave

 

[Weasel]

Sure it helps! Any air that goes in there is drag!

Is it measurable? I was not able to quantify any gains by running a continuous power setting on auto pilot with them open and then with them closed.


Would I do it again? dont know. It was a lot of work!

 

[g zero]

Looks nice ! i guess I'll do some testing with tape and see what results I get .

 

[vlittle]

Very old school, etching your own pcbs!

Great spirit of the endless persuit of perfection, nicely done Weasel!

 

[rvmills]

Very cool project Weasel! Nicely done! Do have any pis of the set-up with the servos attached? Pretty neat!

Bob Axsom tested his NACA closures as well, but I don't recall what he measured. Tried digging through a few threads, but couldn't find that info.

I'd think that it would have some impact, even if incremental. In order of higher to lower drag, I imagine it would be:

1. Open NACA, open vent.
2. Open NACA, closed vent (drag from the opening, but no flow in the duct and scat), and
3. Closed (or taped-over) NACA.

If I had any, I'd cover them for racing.

It would be neat to see the electric "NACA flaps" in operation!

Cheers,
Bob

 

[BillL]

Yeah Bob Axsom did a lot of that testing. I have downloaded and archived many of his posts.

Tom, one thing with pressure in the cowl, it leaks all around the perimeter, and I noted in one post (forgot which one) that leakage from the gear exits blew off the transition farings. There are lots of places for these "jets" to disturb flow. I'm sure you know this looking at your FWF pictures, but did not see how you addressed this aspect. You probably already covered it.

 

[larryj]

Weasel,
Love your NACA duct. I've had the idea of doing the same thing but manually with a push-pull cable for a very long time - and I'm surely not the first. Saving that project for after I get flying ...... having to shelve a bunch of things in the interest of actually finishing and flying the airplane.

 

[n82rb]

just a few things that have been learned by trying to get a few MPH out of a "stock" t-6.

1. air going out is just as important as air coming in. all exit spots must be sealed also. you would be amazed at how much drag is created by air exiting the tail cone that came from the front of the cabin.

2. span wise flow of air inside of the wings and the tail create a lot of drag.



bob burns
RV-4 N82RB