Forum: HoseHeads Sprint Car General Forum (go)
Moderators: dirtonly  /  dmantx  /  hosehead

does anybody have drag and downforce numbers on a flat wing with a 1" wickerbill versus a dished wing with no wickerbill

Just thinking...wouldn't this all depend on wing angle and the like?

Chuck.....

If you test them both at the same angle, 0* or no tilt, then you can get a comparison as to drag/downforce numbers.

The way it was explained to me, the dished wings make more downforce with a hair more drag than a flat wing with a wicker bill, but I don't have any numbers to prove it.

probably...but I don't know so that's what i'm trying to figure out

It would be wise to read a book on NACA airfoils to understand just how stupid both your statements sound.

I don't aim to please.
I aim to hit the target.

Please, o wise and powerful aeronautical engineer. School me. I wait patiently for your response.

How do you get downforce and drag numbers? Test them. Obviously you can't test them when they're mounted on a car, the conditions vary too much, so put them in a wind tunnel. If you come back with mathematics as an end all be all, how do you verify your mathematics? That's right, put them in a wind tunnel and see if the numbers match.

Pick up a book and read. the numbers you are asking are there. School yourself. Most modern wing builders give you a bunk design. There only worried what works best for them to break easiest and not so much on shape.

I don't aim to please.
I aim to hit the target.

You apparently already have the books and knowledge, please share it with us. Prove the claims you're making. Help educate the masses. Until proof is shown, it's all conjecture. I never once stated I knew for a fact that what I think is true, you however think what you're saying is fact, I'm asking you to prove it.

This post wasn't meant to sound condescending, I'm genuinely curious. It may cause me to switch wing manufacturers.

I know that 12 years ago the accuracy of the fluid dynamics equations were far enough off that I would never take them as gospel, just a general guideline, and always use a wind tunnel to check the actual result. That being said, I'm pretty sure that Computational Fluid Dynamics programs have come a long long way in that time. But if you are not using CFD or a wind tunnel, the general equations won't give you a straight up answer. Also wing angle is a very big part of it. What gives you the best numbers at a 0 degree wing angle will not necessarily work best at a 30 degree angle. Throw in variations in air turbulence and wing slip angle, and it can become a pretty big mess. For the record, I haven't done any of this research,since I don't plan on building wings, I just use what's cheap.

I agree. In response to the 0 degree part, I think the OP was looking for a comparison between the two and that would be easy to check. You could set them both at 30* and evaluate them at that angle and get the same comparison. I bet at those high wing angles like that you run into a lot of turbulence because you lose laminar flow off the back ~1/3 or so of the wing.

Yes I do and why am i going to give you something I worked hard for. Why dont you go out and earn it by picking up a book.

If your running test on a wing at a thirty degree angle you might as well throw a piece of plywood up there cause if you think you are going to created anything more then drag numbers you have proved my point you need to pick up a book and read in to what angle wings work best at for creating max amounts of downforce for less amounts of drag and trust me it aint with them flat belly wings with a wicker bill.

I don't aim to please.
I aim to hit the target.

Show me a book that has information on a wing that has the same span length as chord length and operates at 20 to 30 degree angle with no flaps, (and with or without a gurney flap) and i am sure it would provide useful information that a lot of racers could understand and use. Otherwise unless you have done wind tunnel tests or know someone who has and gave you the numbers, your post is f---in stupid.

and if i remember from some BOOK I READ a 4' x 8' piece of plywood can put up to 500 lbs. of downforce with about 80 h.p. of drag...but the rules don't allow 4' x 8' of anything!!!

Ill do one better.

http://www.ae.illinois.edu/m-selig/ads/coord_database.html

Its in there now its up to you to find it.

I don't aim to please.
I aim to hit the target.

The guy who wrote the NASA wing program I've used told me drag is very hard to get numbers for. To get an accurate comparison, you would also need to know how much camber (dish) your wing has. He also told me that camber is the most efficient way to create negative lift, or down force. You can take a wing with positive lift angle, give it enough dish and it will still create down force. Fun stuff to play with.

This is a fun topic! It actually got me thinking about wings as something other than a flip attenuation device. I quit applying any brain power to this topic when they mandated the flat top wing, at which point I figured they might as well make us run sheets of plywood. Now F1- they have some wing tech! I just found out what an F-Duct is, and the guy who came up with that is brilliant!

I would prefer to run our cars with a smaller wing, but allow more efficient designs. Of course this would mean someone with deep pockets would hire and aerodynamic engineer and smoke the rest of us, but it would put some innovation back into sprint cars. (Of course we would all cry when we sat our cars on top of our $2,000 wings).

I would like to apologize to javenus and all the other true racers, fans and the like for the infantilism of 21wforacer...It's is guys like hime, trolls and the like that have caused guys like me, who used to truly like and enjoy coming to this board to abandon it and only paruse through it from time to time. I guess not all of us can be as smart as him. Obviously he is way to smart to share his knowledge...worked to hard for it to share it?!?!? I think that he doesn't have the knowledge or someone with all that knowledge and the ego he has would surely want to prove his worth. 5 or six years ago this was a great place, but he is truly why this place has gone to the birds. I really was interested in this topic, but no matter how harmless, the topics on here always go the way of bashing! Maybe that is what sprint car racing is coming to and the reason that, though I love the sport, only went to 1 race all year. Guys like 21wforacer just put a bad taste in my mouth. CAN'T WE JUST ALL GET ALONG AND NOT HAVE TO PROVE HOW SMART WE ARE OR THE SIZE OF OUR JOHNSON'S!

ok, this is just an opinion and a little thinking out loud here.

my thinking is you get a better down force vs drag number with a dished wing, at least up to some point, because you don't have to have as much angle of attack with a dished wing to get the same down force as with a flat wing.

we don't seem to be using wings on sprint cars really like the upside down version of a wing. we seem to be using them like a piece of plywood catching the air to rock the car back on the rear tires rather than as a wing to suck the car down. we are running such steep wing angles that at some point we have gone past the "stall point" of the wings we are running as far as down force vs drag. we seem to be using the drag more than the down force to help us. we just keep adding horse power to over come the drag.

i used to have drivers complain the wings were trying to suck their helmets off their heads 20 years ago with wings at 14 degrees or less. i don't hear them complaining of that today with wings at 28 degrees.

the more dish we take out of the wings, the more angle we put in them trying to get "down force".

in my opinion we are using the last 12-14 inches on the back of todays wings to rock the car back on its rear tires rather than the belly at the first 12-14 inches to suck the car down on the wings we used to use.

as i said this is just an opinion and a lot of wondering out loud. i am a racer, not an engineer. i just keep raising the thing up until the driver complains he can't keep the front tires on the ground.

to indy and beyond!!