WTF was that crx vacuum thingy???

[legendboy]

That thing was so stupid! WTF is that guy thinking????

Maybe he was trying to keep the track clean by sucking up all the dust???

[Superesc]

I don't know dude, his idea was sound, just not sure how effective it is overall. At the very least he didn't spin out and it was pretty cheap.. 800 bucks turbo!!!!

[speedracer]

downforce

[legendboy]

Originally posted by speedracer
downforce

Sure, but as if it would work! for the amount of time and money he could have got a better engine! I think he needed that more than the vacuum.

[CRXguy]

I think it was the LUDELVR-style side skirts that slowed him down!

[rage2]

Honestly, I don't think a weed wacker with a tiny fan blade attached to it can generate enough vaccuum to suck the car down...

The Brabham F1 "Fan" car, did it use a big fan or a turbine? That worked well, cut nearly a second a lap. But I remember the fan was huge, sticking out the back of the car.

[4wheeldrift]

Its a sucker car. The idea of the fan is this. The fan forces air up and out through the shaft in the middle of the car. The air moving up and out of the car forces the car down into the road very hard. They tried it in F1 back in the 60s, and the car ran I believe one or two races before they banned it for being way too fast (and a bit dangerous, the fans had a tendency to throw debris). Incidentally, the driver of that car is Shannon Wall, the owner of Western Motorsports and a track record holder at Race City. He decided to try a turbo'ed honda sucker car to do something different )

[Ekliptix]

Actually, it can be very effective. If he was sealing against the road properly, and producing even 0.5psi of a vacuum, and the skirts were approximately 6' x 6' = 72" x 72" = 5184"sq. so that's 2592lbs of additional downforce keeping the car down.

This is all theory to me, but I know that when this vacuum car idea was introduced into mainstream motorsports years and years ago, it was quickly banned because there was too much of an advantage by those cars equiped with the vacuum system.

[kenny]

This particular "crx vacuum" did not have a proper seal at all along the road. Most of the time there was an half an inch to an inch gap which would render the entire vacuum system useless.

[legendboy]

hey rage, u gonna post the vid of me wiping out?

[kenny]

the rendering farm is churning out videos from Europe (f1 race) it'll be posted when its done rage2 is workin' on it.

[legendboy]

sweet....thanks guys....

[4wheeldrift]

Originally posted by kenny
This particular "crx vacuum" did not have a proper seal at all along the road. Most of the time there was an half an inch to an inch gap which would render the entire vacuum system useless.

You don't really need a proper seal to make it work. If you had to have the whole system in contact with the ground at all times it would be totally useless because of the change of ride height due to manuevering the car. The vacuum system creates a low pressure area underneath the car and a high pressure system above it, forcing the car into the ground in the same as a conventional wing does. However, because the vacuum system isn't speed dependent for airflow it is much more efficient at lower speeds than a typical spoiler or aerodynamics package.

[legendboy]

I really don't think that this guys crx hoover did anything advantagious.....maybe on a real race car with a proper setup but this guy was using a weed wacker 2 stroke motor with a little fan blade and a 50 gallon drum cut in half. I think he'd be better off saving the weight and spend the money on more screws to hold dat thing together.......or a new paint job, it looks like . ..pretty creative I must say tho......

[Weapon_R]

From what I understand, this fan works to push air upwards, to force the car downwards? Ok...but wouldn't that kind of be equivalent to adding weight to the back of the car? It would help keep the wheels stuck to the pavement, but wouldn't it also create more weight for the engine to pull? In theory, there is no extra weight, but the downforce on the vehicle may be translated into the same effect. And would this even work on a FWD?

[Fluidic]

Either way gents... it was fast, cornered like a mother-fucker and stuck to the track with, what appeared to be, apparent ease...

Peter

[speedracer]

Originally posted by 4wheeldrift
<snip> They tried it in F1 back in the 60s, and the car ran I believe one or two races before they banned it for being way too fast (and a bit dangerous, the fans had a tendency to throw debris). <snip>

Yup, even in FSAE there is a rule that prevents people from doing that. And it doens't have to be a big powerful vacum to have that effect.

If I only paid attention in Physics class.. wait I'm not taking any physic classes

[4wheeldrift]

Originally posted by legendboy
I really don't think that this guys crx hoover did anything advantagious.....maybe on a real race car with a proper setup but this guy was using a weed wacker 2 stroke motor with a little fan blade and a 50 gallon drum cut in half. I think he'd be better off saving the weight and spend the money on more screws to hold dat thing together.......or a new paint job, it looks like . ..pretty creative I must say tho......

The sucker car they made back in the 60s was using IIRC a pair 2 hp lawn mower engines to power the fans and it worked exceptionally well.

And weapon R, because of the relatively central placement of the fan well the downforce has an effect over the entire car, not just one end like a conventional wing. The thing with downforce is, its not really creating any extra weight on the car at all, when the car is first starting out because the effect of the airfoils or suction is dependent upon airspeed around the vehicle. The reason a big spoiler can slow a car down is because of drag, not weight added by downward force. If the car isn't moving there is no (or very little) downward force so there is no drag. Once the vehicle is moving you start to get downward force but the force of the air hitting this airfoil also creates drag which slows the car down (with a large enough airfoil it can actually stop a car accelerating completely if the car cannot overpower aerodynamic drag. In this setup, yes the fan and that is adding extra weight to the car but the benefit is that the car's speed is no longer drag limited because of its very clean aerodynamic profile offered by not needed spoilers to generate downforce. And downforce works on any type of vehicle, front wheel drive, all wheel drive, rear wheel drive, it doesn't make a difference. It just depends on where you put the downforce. If you look at the front wheel drive BTCC cars they are using chin spoilers and splitters to generate downward force at the front end of the car where it can actually do some good. In shannons case, because of where the fan is the downforce is evenly distributed front to rear.

I understand why you guys are skeptical, but trust me this works and it works very well, even if it looks like a total hack job.

[Davan]

Regardless how well it worked for him, I give him props for taking the time to build it and try it out on the track.

[thich]

all I can say was he and that weird giant wing mobile were fast.....