Drag reduction

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Dust

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Troy, Michigan
OK, we all know i am building a cozy, and i would like to reduce the drag, wouldn't we all.

I'm thinking one area that i could try is in the landing gear strut. It currently has an airfoil shape so that it creats a left and a right counterbalancing lift.

I was thinking of changing the shape to have each leg have a no lift airfoil shape.

Does this make sense to any out there?

Talked to klause at lightspeed and he makes them using a wartman aileron airfoil shape for the long ez, and it improves the long's performance, but the cozy landing gear strut is much more airodynamic than the longs to start with

enjoy the build

dust
 

StRaNgEdAyS

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Northern NSW Australia
The question I guess you'd have to ask, is would the no lift airfoil inpinge on the plane's performance, and if not, does it actually produce less drag than the current one.
You could do a little research into airfoils and select one with a lower L/D ratio. That might do the trick. :D
 

wsimpso1

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Hmm, I would not expect much from changing the shape of the gear leg. Once it has a foil shape, that thread is probably run out. Have you read Kent Paser's book? He covers a bunch of aero cleanup, particularly cooling drag and fairings, plus some induction/exhaust ideas... A lot of his biggest improvements were things that the Cozy automatically has covered, but he has some left. After that, you might check out the speed mods on the race planes at Sun-n-Fun and OSH, and perhaps at the various races.

F1 is the ultimate in aero cleanup. Go to an F1 meet and talk to the guys. I know a guy in Belleville MI who is an experienced F1 racer and was number 2 behind Nemesis. He is building an F1 airplane to win it all right now. Send me a private message and I will connect him to you...

Also, I know a couple of EAA Tech Counselors with more than a few inputs on drag reduction...

Send me a private message and I will connect them to you...

Billski
 

orion

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I too am thinking along the same lines as Billski. Once you have a faired section (airfoil) then there is reletively little you can do to reduce the drag count further. You'll get better results in paying attention to several details such as the interfearance drag of the gear coming tino the fuselage. It is the numerous small details around the whole airplane that will probably add up to more of a penalty than just the gear alone.
 

Dust

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Troy, Michigan
what if, because of the angle the gear is attached, it is creating down force as well?

enjoy the build

dust
 

wsimpso1

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Hey Dust, here is my way of looking at it. Just about any foil you can find has a drag vs AOA curve that is pretty flat near the min drag point, so if your angle is withina few degrees of the min drag point, you are just not looking at much drag... And it is just a couple square feet of wing too. Once you get into the junctions of the gear leg to the wing and wheeel pants, you start to find richer ground for drag reduction.

Now if the angle of incidence of the gear leg is really large compared to the main wing, you might want to either go to a simple teardrop form or alter the trailing edge to make it less draggy, but you are still in a pretty small drag region compared to other places on most birds.
 

Dust

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Feb 9, 2004
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Troy, Michigan
OK, now peoples, shoot this idea down.

I'm thinking of playing with the exhaust to create a venturi/augmentor effect to pull the air by the turbo and exhaust and out the rear. like take the 3" exhaust pipes i will have and put it in the middle of a 5" pipe and mess with the lengths until i get a combination that uses the exhaust preasure to pull air thru the augmentor to reduce cooling drag, by creating negative preasure under the cowling, and get rid of waste heat

enjoy the build

dust
 

Midniteoyl

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Sep 3, 2003
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Indiana
Saw something at bd-4.org(??) about the sizing of those things and, at least for this guy, without 'diffusers', his were gonna end up 47" long after the exhaust....

Seems to be a good idea, however, if you can terminate inside the cowling and shorten the pipe hanging out in the breeze...I was thinking of doing the same for radiator cooling...
 

MarbleTurtle

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:whistle: Getting the ol' ball and chain to have a garage sale. What she doesn't get outta there goes to the dump! I'm getting the supplies for a table, hotbox, and glass closet this weekend...
 

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wsimpso1

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Hey Dust, Kent Paser's book describes his experiments on this topic, and an Internet search should turn up info on augmenter proportions. I f I remember properly, the pipe has to have a resonant frequency about the same as your engine's exhaust pulses, and then it has to be big enough to move enough air to decrease your air inlet size, or it is all for nought. Augmenters came and went, and I have to presume for a reason...
 

Dust

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Troy, Michigan
Well, if i study every darn part of this installation in as much detail as i should, my partner will kill me, he wants to fly this plane next year.

So I think i will experiment with a leaf blower

sounds like a plan

enjoy the build

dust
 

Dust

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Feb 9, 2004
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Troy, Michigan
Everyone here knows too dam much, i find i have to re read almost all of the answers to get the full meaning that was said, great problem, keep it up

orion said

"Once you have a faired section (airfoil) "

That really finally sunk in, a great way of thinking about fairings

enjoy the build

dust
 

Sonja

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Apr 13, 2004
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Streamlined gear legs are nice, but what if they don't line up with the streamlines? The airflow at the gear location may be at an angle, the only way to find out is to fly it. If the dead bugs accumulate straight on, the airflow should be fairly straight. Tufts and a camera or mirror are helpful to find separation.
 
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