I would like to see how that equation was derived. It seems kind of weird that the angle is just thrown in the with the rest of the measurements... The units of the final answer should really be ēN. Downforce should be the resultant vector in the Y direction, drag would be the vector in the X direction. I would imagine there would be an cosine or something somewhere in the mix.

 

Homework
Put a fig newton on the hood and see how fast you have to go to get it to blow off. Repeat experiment with a polished hood.
Results to be posted by next Friday to get full marks.

 

When I placed the fig newtons 75 mm from the front and 50 cm from the side on the left and the right of the hood. At 80 miles per hour the one on the drivers side (left side) slid exactly 195 mm's to the rear and the one on the right side only 150 mm's. I believe that the results are due to the fact that I was driving the car without a passenger and thus the car leaned to the left 3.689 degrees. So the test will vary according to body mass.

 

I could have sworn that the manual tells you how much downforce the spoiler puts down at a certain speed...will have to take a look. As far as spoiler deploying my spoiler deploys at 68 mph everytime.

 

in the factory repair manuals (in PDF format) in section 23-Body on page 116, it states that the deployed wing provides 40 lbs (356 Newtons) of aerodynamic downforce to the rear of the vehicle at 80 MPH (129 km/h).

 

I did wonder why no trigonometry was used.

 

When i convert 356 netwons to lbs-force i get 80lbs ????/

 

Suffice to say I nearly drenched my monitor, keyboard, self, and numerous pages of inkjet printed documents (after filling my mouth almost full from a large glass of H2o) during the progressive digestation of the multitudes of complicated practical and theoretical computations offered. The data that almost sent me over the edge was the visual of that wasp! I cannot tell you how many bugs I have seen on my windshield that have suffered that same embarrassing outcome. Can I be faulted for actually feeling sorry for the lil creature(s), and slowing down? Can I be hated for actually speeding up on a few of those occasions? Suffice to say I cannot remember when last I had such a hearty and full bout of natural occuring endorphines, while at the same time not making a huge mess! Thank you members, I salute you!

 

all i can say is ROFLMAO

 

I pushed down on the lever and mine deploys at 62 MPH every time.

 

Mine puts out whenever I ask, but the wing goes up around 64 mph every time. down under 40.

I'd find it hard to believe the wing is effective at anything under 95-100 mph...

 

well needless to say , if the car spoiler is disabled and starts screaming at you at exactly 91 mph it isnt working , it must be doing a mighty important job so i am very thankful for said spoiler!

 

Well, since you dug up this old thread I will report the following. We have had wing discussions many times. We have even insulted each other's wings...ironing board, skate board etc. I attended a mtg of the design engineers last year who gave a nice presentation about the cars. I asked about the wings, and the wings were designed to all give similar numbers of downforce. I also asked about the splash shield under the car since I had removed mine. They also have a role to play on keeping the car glued to the road. I have since re-installed my splash shield and will keep my ironing board....

 

Id like to know where that formula came from. The height seems to be an arbitrary factor and drag on the wing is a multiplier, not a negative term, I just dont see the units working out.

It the wing was up 30 feet it would do more???? And if it is a torque factor, then it would be bad as it would tend to reduce the front down force. Not sure about the equations source. Where do you measure the height?? from the centerline? ground? surface it is mounted on????

Woody

 

After the Woodward Dream Cruise we went to see Eric Stoddard and he said that initial tests of the Crossfire showed that it was worse that a Jeep Cherokee ( ?) type vehicle in the wind tunnel and design alterations had to be made to make it stable at speed.

The basic shape of the Crossfire is like a airfoil which creates lift. So the airflow over the car had to be disrupted, hence the spoilers and limited ground effects.

Simply put the air flows farther over the top of an airfoil so it is less dense = less pressure than the air that flows under the airfoil and this creates lift This is good for an aircraft but not for a car.

 

I suspect I have erred in my use of the above formula but if down force is 80 at 80mph than I get 280 at 150mph. Can one of you math wizards check my number?

 

that cant be true , because that would mean the stress on the spoiler would be that of a 285 pound man on it , no offense to your math , but that spoiler doesnt seem like it could handle the weight , with that said... im going to place a fat guy in my trunk....

 

Why? Then you will get traction but go slower due to weight...

 

but he would be fun to talk too? and isnt downforce the same as putting the extra weight on your car anyways? they are equivalents, 285 pounds of air is the same as 285 pounds of man?