aerofoil tubing

[Jon_Dal]

Has anyone used aerofoil tubing (or carbon fibre aerofoil) for their a-arms? I can't remember ever seeing any pictures of any. And yes I realize that the benefits at 100km/h or so are probably not much, I'm just curious. If so, how much more expensive is it? My guess is quite a bit more expensive. I tried looking around for suppliers just for fun but didn't turn up much.

[Jon_Dal]

Has anyone used aerofoil tubing (or carbon fibre aerofoil) for their a-arms? I can't remember ever seeing any pictures of any. And yes I realize that the benefits at 100km/h or so are probably not much, I'm just curious. If so, how much more expensive is it? My guess is quite a bit more expensive. I tried looking around for suppliers just for fun but didn't turn up much.

[Jersey Tom]

Nope. No need. I take the cheapest, most available, lightest option and run with it.

[John_Burford]

OH YA. Penn State 1996 or 1993

Somebody was filming during the endurance. They were setup near a hard braking zone. Penn State's car comes into the center of the camera shot when the lower front a-arm (with airfoil sections) BUCKLES! The corner of the car grindes into the pavement, and the car stops a couple of feet from the camera. The driver looks up into the camera, and you can feel my thinking DOOH!


John Burford

[Bryan Hagenauer]

steel (http://www.aircraftspruce.com/catalog/mepages/4130streamline.php) or aluminum (http://www.aircraftspruce.com/catalog/mepages/struttube.php)?

[Jon_Dal]

Haha....there's been some interest in using carbon fibre in our team for our a-arms. I'm just imagining hitting cones and breaking them...and crying. Anyway, the aerofoil was about as expensive as I was thinking. Thanks for the link.

[D-Train]

We had a similar experience to Penn State in 2004. Buckled the aerofoil section tubing on an upper A-arm (with pullrod suspension), had the front of the car scraping around corners for half the enduro run. Still managed to finish though.

Has anyone made their A-arms out of Aluminium before?

Also, it is out there in carbon fibre... might be a little big though. http://www.cstcomposites.com/Foil_and_Elipse.htm

[Erich Ohlde]

what was the dimension on the tubing you [teams that have had aerofoil tubing fail] were running?
I've been looking at running aerofoil on our 07 and the tubing i selected was in the neighborhood of 1000% stiffer (geometrically) and thats the narrower section.

[Jersey Tom]

1000% stiffer in terms of what? Bending in the ground plane of the car? Or the buckling modulus? And how much heavier for that 1000%?

How stiff is stiff enough?

[Erich Ohlde]

bending from lateral force of the car. This is based on the geometric stiffness (area moment of inertia). I'm actually looking at a 250% reduction in weight over 5/8x.035" tubing.

[Jersey Tom]

Wouldnt a 100% reduction in weight already put it at 0 lbs?

Interesting. Sounds like mighty thin stuff though. .625 OD x .035 wall tube is pretty light as it is.

Whats the critical buckling load?

[Erich Ohlde]

yeah. i mixed that number up, it was like 2am last night when i was running those numbers. Haven't gotten into buckling yet.

[drivetrainUW-Platt]

that stuff looks soo cool thou, if you pulled it off you could create a plane wing effect with your a-arms and get some downforce....

save your money and get the round tubing unless you are going to be racing at a LOT faster speeds then we see in fsae.

[Erich Ohlde]

So, anyone got those dimensions?