New under tray for GR55B

h/climb central · 2 Feb 2008, 09:35 (Ref:2118934)

Does any one know any thing about the new floor that has been built for the Gould, in Aust we are starting our state championship this weekend and Andrew Howell has one of these new floors on his GR55B, it is said that it produces an increase down force of up to 30%,Hmmm, the old floor must have been hardly working to get an increase of this amount.

b1ackcr0w · 5 Feb 2008, 08:34 (Ref:2121387)

It depends what the 30% is of. Overall downforce? I don't know. I'd have thought 30% more than the downforce the old floor maybe.

Don't forget the floor of the car is an area where massive gains can be made. Ground effects and suchlike....

Steve Wilkinson · 5 Feb 2008, 10:44 (Ref:2121507)

The last time I stood up at Martini at Wiscombe (2006) I noticed that the overhanging trees on Castle Staright were hardly disturbed by many of the big single seaters as they passed underneath. Therefore does this mean that (a) they were not moving enough air to actually achieve a great deal of downforce, or (b) that the aero package was being efficient?

zac510 · 5 Feb 2008, 10:52 (Ref:2121515)

Photos?

**Woolley** · 5 Feb 2008, 11:19 (Ref:2121533)

Or the air that was moving is not moving upwards? With my extensive knowledge of guesswork, and extremely limited knowledge of aero, I'd guess the greatest disturbance occurs where you move the air to, not from. So if you're creating downforce you're pulling it down from above which won't move the trees much, and leaves all the crap at ground level (they certainly pull stuff up off the track - just watch when they go over leaves or a plastic bag). This also conveniently explains why F1 cars can't follow each other.

Easy, this! Probably wrong, but that never stopped Wikepaedia either.

Steve Wilkinson · 5 Feb 2008, 16:29 (Ref:2121743)

Quote:

Originally Posted by Woolley

Or the air that was moving is not moving upwards? With my extensive knowledge of guesswork, and extremely limited knowledge of aero, I'd guess the greatest disturbance occurs where you move the air to, not from. So if you're creating downforce you're pulling it down from above which won't move the trees much, and leaves all the crap at ground level (they certainly pull stuff up off the track - just watch when they go over leaves or a plastic bag). This also conveniently explains why F1 cars can't follow each other.

Easy, this! Probably wrong, but that never stopped Wikepaedia either.

I thought the air moving downwards as you suggest would in turn pull the branches of the trees downwards, or am I missing something basic in aerodynamics?

If you see cars blasting down a straight in the wet the rooster tails always fly upwards not down! As illustrated below:

Rodney Eyles at Pembrey

**Woolley** · 5 Feb 2008, 23:17 (Ref:2122041)

I definitely didn't claim to know anything about it! Pure supposition on my part.

When you do see a car in the rain, there's little energy visible in the upper part of the trail - you can see the dense part of the spray (nice picture, BTW) above, which usually looks fairly turbulent. Anything higher just seems to drift.

mcb666 · 6 Feb 2008, 14:25 (Ref:2122479)

Steve,

remember Doune and your commentary post. The trees don't half get sucked down...

Richard

It could just be the vacuum created by the Predator.

Pike · 6 Feb 2008, 19:20 (Ref:2122691)

Its all to do with low and high air pressure and directing each up and over the various parts of the car to optimise the speed against grip argument. I.e the car can be set up to be really fast in a straight line but not have much aerodynamic grip in the corners or the car can be relatively slow on the straight but have ooodles of aero grip in the corners. Somewhere in all this mix the floor of the car comes into it but not just in aero design as in ride height as well- remember "the plank" that was bought in to make F1 raise the ride height to slow them down?

I think the air should be pushed upwards as the car moves along the track therefore pushing the said car onto the track. If the wings dont push the car down then what is the point of them?

I think the spray off a car is mainly the open wheels throwing water up - just like a truck on the motorway but the aerodynamics do throw some water up.

I could be talking complete b*****ks and wouldnt be surprised if I were!

b1ackcr0w · 6 Feb 2008, 21:08 (Ref:2122770)

Quote:

Originally Posted by Steve Wilkinson

The last time I stood up at Martini at Wiscombe (2006) I noticed that the overhanging trees on Castle Staright were hardly disturbed by many of the big single seaters as they passed underneath. Therefore does this mean that (a) they were not moving enough air to actually achieve a great deal of downforce, or (b) that the aero package was being efficient?

Stand on the Marshal Post Castle 2, you feel it there. For fear of being a smart alec, the effect of aero surfaces is not to displace air, or create high preassure zones. It's actually the low preassure zones (underneath the wing on a race car or on top of the wing on an aeroplane) that do the work.

**Woolley** · 6 Feb 2008, 23:25 (Ref:2122898)

Look at us, couldn't design a wing between us, I reckon! One thing I do remember from school physics, Pike, is that the wings are there to pull the car down, not push it, as BC more scientifically described.

Right, so the next great piece of science on a hillclimb - 500cc Jedi, could it pull the skin off a rice pudding...?

Or to put it another way, better leave the rest of this thread to the experts who know what they're talking about, and that doesn't include me!

Pike · 7 Feb 2008, 18:18 (Ref:2123407)

Wheres that aerodynamist we all know when u need him???!!!!!

Dan_Q · 7 Feb 2008, 21:45 (Ref:2123583)

it doesnt include me either- but I'll agree with pikes post from yesterday......

the air travels further under the cars wing than over it creating a pressure difference as the air speeds up more underneath.

not really adding anything here just confirming what I believe to be correct!

as for undertrays I would say that race cars are getting like some modern aircraft- the body is designed to crate lift as well as the wing, which means you need less wing = less drag = more speed.

hope that makes sense and doesnt just confuse matters!

PS I could well be talking cod ****e too

blackx · 8 Feb 2008, 08:52 (Ref:2123879)

Quote:

Originally Posted by Pike

Wheres that aerodynamist we all know when u need him???!!!!!

Probably doing 40mph down some Swiss hill on a bike instead of 140mph up some hill over here .....

He may even be working