I agree 100%. I graduated with a bachelor's in aeronautical engineering a few years ago and thought I could use my degree. I even got a master's in mechanical. I had a lot to learn. I now work directly in the mechanical/aero world on some of the most high-tech products in the world, but all the theory you guys just shot out has no relavance to real products. If the Evo was designed by only aero and mechanical engineers, we'd all be driving Indy cars.

 

I actually have a pretty good understanding of how all that works. The fact of the matter is, the engineers are still going to try to squeeze some engineering into the design. It obviously won't be a perfect design, but there is some engineering behind it. Any time someone is trying to sell a product they have to make certain concessions, it's just part of business.

-Paul

 

wow i just read 3 pages of garbage and this is the only worthwhile answer on here.

congrats trinydex.

and just for reference, we run a 4 element wing on our race car. we normally don't run a gurney flap on the last element because the "legality" of it is in question for our competition (leading and trailing edges must have certain radii). anyway, we have done windtunnel testing with our wings with and without the gurney flap and even to our surprise it increased downforce. this is with a last element that is nearly vertical with so much angle of attack. the flap was literally pointing forward. drag is not an issue with us as we make more power then we can use, however, the Cl/Cd ratio is still good enough that even if we were power limited, the downforce is worth considerably more in track times then the drag would cost us. it would be a different story if we were going 200 mph. we reach speeds no more then 80 mph.

the multi element wings feed eachother in essence. it allows you to increase the angle of attach without stalling the wing. watching the smoke test through the wing elements on the windtunnel is really quite amazing. you can see when you reach stall with to much angle of attack. and you can even see the effects of the flap. endplate design is also critical as you can see the high pressure air literally roll over the endplates if they are not large enough. this will effect the downforce generated at the outside edges of the wing.

if you really want to make significant downforce with an evo, your best bet is to make a flat bottom undertray with some tunnels at the end. lower the evo, and you will make a ton of downforce that way. also the flat bottom will greatly reduce drag.

 

Again read what I already posted. Thats exactly my point.

This is so true. Wow if you read 3 pages of garbage then I would advise you to learn how to read a little better cause most of the info on here is quite useful. He just repeated what me and PVD04 stated already in other words with of course some of his info in it too.

Oh well I guess let people buy what they want.

 

right... i just said they work, and you clearly said they are pointless.


like putting a wing on a fwd car? well let me inform you of the physics behind a wing, tire grip, and handling ability....

wings generate downforce. downforce increases the normal force acting on a tire. lets review: Force of friction = mu * normal force. a high force of friction means more "grip" to the road, thus better handling, acceleration, and braking. in the case of a FWD car, putting a wing on it will increase the downforce to the rear wheels. the rear wheels will then be less prone to oversteer in turns, increasing the lateral acceleration limits.

it doesn't make a difference if it is FWD, RWD or AWD, a wing generates downforce if it is shaped properly, and installed in a good location. increasing downforce WILL make your car handle better. think about it, if the formula 1 cars didn't have a wing on the front because they are RWD, they wouldn't be able to handle nearly as well as they do.

the wing does not need to be able the "Drive" wheels because at speeds where the downforce makes a difference, you are not going to be breaking traction by HP anyway.


i just read over your posts a second time because i also missed any detailed answer by you as to why a gurney flap "is pointless". please direct me to the scientific data rather then your uncle who works at lockheed.

apparently i missed this one too. but you are waaaaay off here. drag does slow a vehicle down, but not at all by a "decreased chance of skidding the tires". downforce does that. drag acts perpedicular to the normal force, which i'm sure you know already. drag slows a car down by surface friction and a pressure differential from the front to the back of the "body" moving through the fluid. in this case air. i think you should to take some more classes online at calpoly and maybe join their formula team so you can learn how car aerodynamics work. or better yet draw a Free body diagram of a car with drag and explain to me how drag will decrease the tires chance of skidding.

 

So you guys would really go out and spend more then 400 bucks on a hood that may save you five pounds. Why not take the time and de-glue and de-tar your car. Or invest in Alky injection and get 60-80 HP. I cant see the point of spending near 500+ for dry carbon fiber because its five pounds lighter maybe. I have seen people who drive cars that looks mean more then how fast your car is. The drive eclipses with gay wings and have neon kits lol. Sorry Im just not going to spend 500+ for dry carbon to look cooler.

 

when you say dry carbon, are you reffering to wet layup, or prepreg? prepreg is far easier to use, and generally looks better and certainly is lighter. the wet layup is typically done in very low production, and the much thicker resins due to poor manufacturing sometimes give it a "glossy" look. i have never heard the term dry carbon though. the wet layup carbon comes in a roll that is dry, and you add your own resins... is that what you mean?

but i totally agree with you... spending ANY money on a heavier carbon hood is not going to get you anywhere. the aluminum hood is extremely light as is, and i actually heard the carbon hoods are heavier in some cases. if you are going for extreme weight savings, then by all means go for it, but find a light one!!!.

 

If you are building a track car then why not? If you are doing it for a street car and just like expensive and exclusive parts to make your ride standout and it brings you personal satisfaction, then why not? IF you like the wet look of the cheaper hoods, and don't care that it adds four pounds, but that's what you want, then why not?

 

thats Evom <except Offtopic, which is like uber better> for ya

 

dude... i'm talkin' about spending thousands for a deck lid that weghs 7 pounds....

 

i wanted to make one small comment, perhaps you can clarify. i'd like to say that the gurney does not in fact produce any downforce of it's own besides the "angle of attack" type of downforce, wher ethe normal force of the air hitting it has some vertical component.

that said it can SHIFT your downforce curve WAY up in the velocity range which i BELIEVE is what you were seeing in your tests (very cool btw, THIS is the **** i live for!). basically where you were no longer seeing downforce due to flow seperation, turbulance and lots of drag as a result... the gurney recombines the air flow and you see BIG downforce increase because of that.

let me know what you think.... and i mean no offenses

 

I'm no engineering wizard like you guys seem to be, but wouldn't the gurney also slow down the airflow on top of the spoiler making the speed differential between the two sides greater, therefore creating more preasure at the top?

Or should I just leave now?

 

no you shouldn't leave, just read this:

the gurney speeds up the air over the top of the wing. this may seem a bit counterintuitive but it's from the fact that the massflow is more of less conserved, so to get "over" the obstruction only means increase in velocity, no other way.

what you're saying brings up an ancillary point though as it would slow down the air directly in the "pocket" inside the gurney flap. that would of course create a high pressure zone furthering downforce production, however i would believe those effects to be not as big as the 'modification' to the wing would produce

 

Wow, too much good stuff!

 

Like I said if looks are important to then go ahead, Get some neon too your car will stand out. All Im saying is I would just like to build a faster car, Not one that "stands out" and looks cool.