apexanimal

We've been working on an idea to stay under the penalty area for a rear wing/spoiler (< 250 in/2).

The distance of the nb trunk is approximately 40" wide, and if I used an endplate mount at those points, this would leave me with a wing of approx 6".


Does anyone know of a decent short chord wing out there?

Occam’s Racer

There's a cheap wing you can find on eBay and other places, sold under a variety of names. It measures roughly 53x4.5" and would come in under 250 in/2. I can't speak for the efficiency of the wing, but it's cheap, less than $50 US, shipped, and it has mounts that are adjustable on the underside. I have mine set at 40" with wing stands in the trunk gutter. The mounting slots make it a pretty stiff, and light, at about 7 lbs with end plates I used a double-decker version of this wing, but I think maybe the single element might work better. I have since moved onto a 9 Lives wing, but I still have the eBay wing kicking around.

I've since modified the underside with a pine baseboard (no kidding). This is because the bottom of the wing is flat, and has mounting grooves in it. And as we all know, the underside of the wing is what matters most, and so I was trying to improve airflow for better attachment. But this is clearly just a way to waste time, since the 9LR wing is so much better. However, this kind of thing might work just fine in your rule set.

Here's a link to one, but you can find different mounts and end plates with the same wing.

flier129

iTrader: (7)

Are you running your normal airdam and flat undertray along with this? Do you plan to mount the tiny wing at roof height?

Curious to know if the imbalance of aero, front heavy with this, would be worth the 3% gain.

apexanimal

normal airdam and flat undertray.

we don't need much df in the rear to balance the front atm... i've been bugging johnny to get that low df package, specifically the endplate mounts, up and running... poke him in the eye for me.
mounting height wise, we're thinking to start it out low - but a few inches off the trunk so it won't act like a spoiler... higher if we need to. if johnny had those endplate mounts up and running i'd run it higher.


occam - i've seen that one and find it's about the only option i can find out there. thank you for posting bottom pics of the wing - i didn't know that it was flat down there.

Occam’s Racer

Steve, I tried to PM you, couldn't attach pics you asked for.

First pic shows the underside. I set the mounting width to 40" and used pine baseboards glued to the bottom. I then shaped them with a belt sander. Went very quickly.

Second pic is the profile of the wing, you can see the flat spot on the bottom with the twin mounting rails. These make the wing pretty stiff, especially compared to the upper wing, which is a noodle. I'm currently filling in holes on the upper wing where I mounted the gurney flap, and probably doing something else with this.

I measured the wing area and it's 246 in/2, just legal.

-Mario

apexanimal

disregard my pm - thank you sir!

Occam’s Racer

I've looked at a lot of wing profiles and I don't know what that bulge 1/3 of the way up on the pressure side could be for. Probably just looks? The wood I added to the bottom makes the wing very thick for its chord, and possibly too thick. I could have flattened it out more, but I was blending the curves on the leading and trailed edges. However, the thickness should make it work better at a higher angle of attack. As would a Gurney flap. A 1/4" flap would be about 6% of the chord width, and that's in the right neighborhood. For $50, can you go wrong?

apexanimal

Price and square/in area are right in the ball park. A friend of mine and I are going to plug it into his program and see what some general drag/lift numbers are!

apexanimal

well this one has a different profile!

We're running this one through some data, and plan on shortening the span and adding a bit of chord length.

Occam’s Racer

My wing is different, it has two tracks underneath so that the wing mounts can be of any width. Your wing profile is certainly better on the bottom, but I wonder if the wing will flex more with less internal structure? If I was limited to 250 square inches, I'd go after a high aspect ratio (62"x4" ideally) . By shortening the wing and increasing the chord, you'll get a less efficient wing. But I'm guessing you have good reasons for this, such as end mounting the wing at 40". I started following your FB page, looking forward to seeing the results.

apexanimal

we put a 125lb woman on it today and it held up just fine! a touch of deflection but nothing crazy at all.

our thought is to endplate mount it to keep it as efficient as possible (and able to due to the size restrictions) - nb trunk is approx 40" wide.
we're thinking if we finish up the bottom profile and extend the chord to maximize the area we're allowed.

the wing came as 4,11/16" chord, 43,3/8" length, and 3/4" thick at the front-most bolt