Wings and such

Anything aero-related (wings, under-trays) etc. Separate from "Wind Management", which deals with protection from wind buffeting.
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rennkafer
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Re: Wings and such

Postby rennkafer » 13 Feb 2018, 14:06

Here's an idea.

1974 shadow DN4, rear wing probably generates as much downforce as anything we're likely to.
Shadow-DN4-Chevrolet-110373.jpg


Rear wing mounts are fabbed from tube with a sheet metal cover (DIY Aero tube), bottom has a horizontal tube welded to it. Attached to the car with a single bolt in double shear (bracket welded to chassis)

Shadow-DN4-Chevrolet_17.jpg


The two forward rods are just fastened with pip pins (also in double shear), easy to remove.

Shadow DN4 2.jpg


When you remove the pins it rotates out of the way to remove bodywork and work on the engine.

Shadow DN4 1.jpg
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Re: Wings and such

Postby Midlana1 » 13 Feb 2018, 14:20

Very helpful pictures, thank you!

I'm aware that when trying to figure something out, I tend to come up with some idea and focus entirely on going that way, and not zooming out frequently to see what else is out there.

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Re: Wings and such

Postby rennkafer » 13 Feb 2018, 15:53

I have the advantage of having worked on a lot of cars with fairly rudimentary aero on them ('60's/70's F1/F2/Can Am), which is doable for mere mortals, unlike more modern cars.

That was just the first one that popped into my head that I thought may be adaptable to Midlana. I'll have a look through my pics and see if anything else looks relatively simple.
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Re: Wings and such

Postby Midlana1 » 13 Feb 2018, 18:00

Given that these wings are small and require a 1" diameter tube through them, and because it's it's going to be a two-element assembly, I'm unsure how to proceed.

Do I make a fixed assembly, make the trailing wing AOA adjustable, or even both?

I assume the main wing can be fixed relative to the mounts and that AOA can be altered with the mounts.

I guess the real stumbling block is what to do about the trailing wing, suspecting it needs to be adjustable but unsure how. Do I leave the wing segments loose on the tube and anchor them in position via end plates permanently attached to the wings, and the end plates bolt to the supports at the desired angle.

Or, rivet the wing to the tube and adjust the tube angle somehow. If that's done, how does the rotating assembly attach to the end plates at the outside ends. Seems I'm right back to making intermediate plates that bolt to the wing, then the plates bolt to the mounts/end plates.

As you can see, I'm at the flailing about stage.

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Re: Wings and such

Postby rennkafer » 13 Feb 2018, 21:06

I've seen all of those done, Kurt.

Here are a couple ways the rear element has been done. May have to enlarge the pics a bit.

This one is a Ralt RT-1 Formula Atlantic

March 79B.jpg

RT-1.jpg



This is a 1970 Brabham BT33 F1

BT33.jpg

Brabham-BT33-Cosworth-81979.jpg

historic-brabham-cosworth-bt33-up-for-auction.jpg
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Re: Wings and such

Postby Midlana1 » 10 Apr 2018, 13:52

Here's a picture of the general layout. Many thanks to Def for answering my dumb questions behind the scenes. His suggestions included a 3-3.5mm slot, and shifting the second wing forward so that the undersurface of the combination of the two is smoother than what I show here. Also, he suggested a base AoA of the forward wing of 0 degrees, and a maximum of maybe 15 degrees, with the aft wing around 32 degrees more.
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Re: Wings and such

Postby rennkafer » 11 Apr 2018, 07:11

I think it would be helpful to everyone to see at least some of the "behind the scenes" Q&A that lead to that Kurt.

How are you planning on holding/adjusting them?
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Re: Wings and such

Postby Midlana1 » 11 Apr 2018, 10:17

I came up with the angles and spacing from the books Race Car Aerodynamics by Katz, and Competition Car Aerodynamics by McBeath, with my proposed placement being sent to Def for comment. I have no idea how often he or anyone else visits this website, so my questions were sent via email to ensure he'd see them in a timely manner. His comments:
Based on the wing profile, I would probably up the slot gap to about 3-3.5 mm. That will also help keep it from closing up under high load, which would cause a huge reduction in downforce, and probably lead to some bad aero flutter of the upper element. You also generally want the bottom profile to be a smooth line. If the trailing element “sticks out” into the flow, it’ll not work as well. Looks like it might be sticking a bit proud now.

A 32 deg AoA between the wings is probably a good aggressive first go. I’d also adjust both elements at the same time for most coarse adjustment. I’d probably set the min at the main element being 0 deg AoA, then a set of holes up to about 15 deg AoA will probably cover the range to stall pretty well. I’d probably do 5 sets of holes at 3 deg AoA each. You can offset the pattern if they’re too close in one line.

As far as how to mount them, the plan is to have small end plates attached to the wing material, with holes allowing the spar to pass through. Those plates will bolt to the main mounting plates, which in turn are attached to the car. Right now, the pitch between the two elements will probably remain fixed, with downforce adjusted by changing the pitch of the entire assembly. While I have a couple ideas about how to adjust pitch of the trailing element, because of the spar passing through, adjustment's not simple and I may skip it entirely.


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