Going high tech

[RV8RIVETER]

Watch out you SARL types, Bob, Bob, and Mark, ect! I am going high tech!

I raided my retirement account for $35 and bought a used wind tunnel from my local school district. Cleaned up the dust, replaced the on/off switch, and it runs and looks as good as new.

[rvmills]

Pretty cool Wade!

Lemme see, if we get busy, Bob can send you wingtip mock-ups, Mark can send you EVO-2 wing mockups, and I can send you ram air inlet mockups...really itty-bitty mockups! Better get those tweezers and magnifying glasses ready!

How much will tunnel time cost us?!?

The SARL boys be warned...there's a new scientist in town!

Have fun with it, and show us what ya test in it!

Cheers,
Bob

[Bob Axsom]

Originally Posted by rvmills

Pretty cool Wade!

Lemme see, if we get busy, Bob can send you wingtip mock-ups, Mark can send you EVO-2 wing mockups, and I can send you ram air inlet mockups...really itty-bitty mockups! Better get those tweezers and magnifying glasses ready!

How much will tunnel time cost us?!?

The SARL boys be warned...there's a new scientist in town!

Have fun with it, and show us what ya test in it!

Cheers,
Bob

Seriously, what he said! If you get any test photos I would like to see them Posted.

Bob Axsom

Bob Axsom

[panhandler1956]

I love it!

The fun you could have with that! Can't wait to here about some of your experiments!

[pierre smith]

I can see testing "roll your own" NACA ducts, hockey puck GPS antennas...pop rivets vs flush rivets on a -12, filled-in elevator tips and so on....airfoil shaped latches on sliders and tipups vs unmodified.

Best,

[Ironflight]

Very neat Wade! We have a wind tunnel in a hangar on our field that belongs to an Aero PhD friend - but it hasn't run since he moved in (neither has his Vagabond....), and would require some "work". I suspect that yours will provide hours of enterntainemnt!!

paul

[RV8RIVETER]

Glad you all got a laugh. I am looking forward to hanging out with you guys at my first SARL race.

Being serious for a moment, I am currently trying to rig up an experiment to compare 2 different designs for my flush fuel vents with the stock set-up. I just need to scrounge up or build a high resolution manometer. I will post pictures and data when done.

If I can come up with a low cost smoke generator, I was thinking I might get some good visual data of the wing leading edge/gear intersection flow.

[Bob Axsom]

1 - A possible experiment would be interlocking airfoil shapes like a landing gear strut and the interface fairing with the fuselage. Comparative test with the joint naked vs. taped.

2 - The chord of the RV-6 airfoil is just under 5 feet (approximately 4 ft 10 in). It looks like you could produce a 1" to 1' scale outer wing section and test various tip designs on it. I think I can still dig back through my records and validate your experiments with respect to stock, flat, semi-flat and streamlined tips.

3 - Same method as "2" but change the length of the exposed wing and record differences in lift and drag.

Smoke would be good, strain and maybe thread tufts could be tried as means of comparisson. It will require careful work.

Bob Axsom

[RV8RIVETER]

Ran my first experiment today. I compared my mark 2 flush fuel vent to the std plans 45 cut aluminum tubing using a manometer to record the readings. It took some "creative rigging" as the wind tunnel is meant for flow and drag measurements and the design creates low pressure. I found that if I pumped the inlet with my leaf blower I could get positive dynamic pressure. Since I am directly comparing with the same set up, it shouldn't matter about the flow errors induced.

The results are the flush vent is equal to or actually slightly better than the std vent in total pressure. Pressure recorded with a Dwyer magnahelic gauge 0 - 2 inches of WC. The maximum recorded avg readings for pressure were;
Std tube = 1.9 inches of WC
Flush vent = 1.9 + inches of WC. Gauge increments 0.2" so needle position is subjective.

Vent in place on the wind tunnel wall.


Vent mold.


Vent itself.

[hevansrv7a]

Paul Lipps has a posthumous article in Contact magazine that denies slowdown. Jack Norris and many others believe in it. I am a doubter because I have not been able to observe it in open blower tests. This would be a good experiment. However, we need to measure velocity, not pressure.