INTELLIGENT dynamics ??

[abisec]

HEY MATES,

WAS JUST TOYING WITH THE IDEA.....AS WE WER WORKIN ON OUR FSAE RACER......WE GOT ACTIVE RIDE.......INTELLIGENT IGNITIONS.....VARIO CAMS.......BUT WHAT ABOUT INTELLIGENT DYNAMICS??

mates throw light on this idea please.....

in formula1 consider the .....front and rear wing sections being controlled(physically adjusted) in proportion to the steering angle and a little help from slip angles and yaw........

consider a fast corner......as the steering whell diverges away from the "straight ahed" position the wing sections will be made to converge proportionally to generate max downforce needed to take the turn(pre calculated using the slip angles and the yaw sensors)

consider a straight.....as the steering wheel is in the "straight ahed" position the wing sections will be concaved to produce the least downforce an hence less maximum speeds...

however mates i think the whole system would definetly have to be based on pneumatics as unbeliveably fast reaction times would be needed....and wat the heck.....pneumatics are used for valve actuations in an f1 engine right? having 8000g's(debatable...........!) of acceleration figures.


so is the new cost cuttings and increase in downforce going to "DEMAND" DYNAMICS.......??

POUR YOUR VIEWS MATES....

[Micky]

Wouldn'y adding pneumatics all over the front and rear wings severly hamper the aerodynamics overall?

Is it even legal to do this?

Good point though, could be another case where BAR could bend the rules

[Scuderia_Russ]

Sounds like you will have a car that is either bolted to the track or a nightmare to drive. Wings would have to respond to steering input immmediately, among other probs.

[abisec]

B.A.R havin bent everything inside and outside their pants wont be tryin this out (at least this season).........but with the low power v8 engines comin up this could be direction teams may take to counter the increase in lap times.....

me thinks this idea would suit the likes of oval racing more where speed(pneumatics) required would be relatively lesser considering the lack of chicanes and tight corners.......what say.....

and just realised this thead should have been in the aerodynamics section....sorry guys...

[bh]

You're talking about aeroelastic wings.

http://www.afrlhorizons.com/Briefs/Mar03/HQ0210.html

Somebody did a senior project at our school using actuators inside of a flexible wing to change the shape. It would work.

However, unless you are on a huge FSAE team, be carefull of getting in over your head. Just getting wings alone is a huge project. Then you'd have to get the elastic wings. Then design a control system to use them.

A far easier method of active aero would be to simply change the angle of attack. UTA already does this by way of rotating the wings around a leading edge pivot. The trailing edge is attached to the bellcrank, so as the ride height changes, the wing angle changes.

The other option would be either pneumatic actuation or electric. Neither method would be light, and the judges are already going to be skeptical of wings due to the added 20-30lbs of weight on the car. The actuation would probably weigh another 5-20lbs.

FSAE being the only type of racing that allows active aero, you arn't the first to think about it. But as we all know about FSAE, it's easy to come up with ideas, but implementing is a whole other world.

[riff_raff]

As a member (in good standing) of the SAE, I feel compelled to turn you for attempting to cheat in the formula SAE competition. On the other hand, I admire your attempt at "thinking outside the box", so I guess I'll let it go this time......

Here's the rules regarding moveable aero surfaces, for the 2005 formula SAE:

"3.7.3(B) The vehicle must maintain all required specifications, e.g. ride height, suspension travel, braking capacity, sound level and wing location
throughout the competition."

Good luck! And here's a tip: most of the competitors in the formula SAE's that I have seen, fail to even finish. So focus on a design that is straighforward, reliable and durable. Remember too, that you are also scored on design and cost.

[abisec]

oh no mates....this idea just struck us....but there is absolutely no way that we would be implementing this on our sae racer...besides we are the ones who are starting the fsae custom in our college.we will be workin to keep everythin as simple as it would possibily be.our only goal is to have a good foundation racer for the next year...on wich we can improve.

[bh]

Whoa, you need to get off your high horse. No one is trying to cheat here, and if they were, there are far better ways than through some crazy aeroelastic wing design.

You need to read that more carefully. It does not outlaw active aero. It states that the vehicle must maintain REQUIRED specifications. There is no wing angle specification besides the basic rules for wing location, LE radius etc. It is trying to keep teams from removing wings or drasticaly changing them for skid pad and accel events. Just a few lines above, it says that adjustment of wing angle is allowed.

My team runs chassis mounted wings. They move in reference to the ground, and teams with suspension mounted wings move with reference to the chassis. So tell me how our wings must not move?

And, if that outlaws active wings, then how has UTA passed tech twice now with dynamic angles of attack? That and their wheels are the most widely publicized parts of their car, so don't try to say they hide it.

[abisec]

as the rule 3.7.3(b) currently stands,prohibits only varying suspension settings...i.e preload,ride hieght,track ,rebound etc......but def dosent have a conclusive say on active aero...and most def not on dynamic angles of attack,besides this has already appeared in previous events...besides "bh" is it worth goin for chassis mounted wings cosidering we are first timers.....?

[Scuderia_Russ]

I sometimes post on the fsae.com forums because there is an amazing wealth of ideas and information that could be beneficial to me and my single seater build. Although i'm not qualified to say as i have never had the chance to take part in the competition, from what i've read from other posters involved with the comp, wings aren't usually worth the weight penalty for the speeds being undertaken. (even though some of the videos that entrants have posted on the site show that these cars can really shift!!) Wouldn't a diffuser be better all round? Are undercar aero devices alllowed? Like i say i'm not involved so i don't know the rules.

[abisec]

rule 3.7.1:

"no power device may be used to move or remove air from under the vehicle exept fans designed exclusively for cooling.power ground effects are prohibited"

[bh]

The rules in fsae restrict the location of the wings, powered underbody effects, and leading edge radii. Thats pretty much it. This is by far the most unrestrictive set of rules for racing... You can do anything you want if you meet those rules.


Our car is driven more at real autocrosses than at fsae events. Therefore, our car is really designed for a track with speeds around 40-50mph instead of the standard 30mph of fsae. To us, wings are a huge benefit, without a doubt. Are they a big benefit in fsae? Wings were a help in 2004 Detroit with the fast track, but not so much in 2005 with the slower track. Really, its on the borderline whether or not they are beneficial. NC State did a SAE paper that ran some calcs and determined that they were an advantage, however, designing a light set of front wings that can take cone hits is still an issue after running wings for years. As a young team, don't even think of wings. Not enough benefit compared to how much they use in resources, and if done incorrectly they will not help at all.

As for underbody, I have heard two trains of thought. One is that due to the low speeds and small car size, it is hard to get enough of a pressure difference to make significant downforce from it. Without a doubt, the majority of downforce comes from wings.

The other train of thought is that if you can build an undertray that weighs 10lbs, and makes 20lbs of downforce, it is worth it. Not everyone, including me, agrees with this idea. That's still an added 10lbs of weight and a big hit in the cost report.

Wings are iffy. Some say they hurt, some say they help. If you have limited resources, use them on other areas that will yeild a more difinitive benefit.

[riff_raff]

As far as lift-to-drag characteristics goes, a well designed underwing is best. Remember back in the days of unregulated F1 aerodynamics and the cars were running ground rubbing side skirts. They got rid of the front and rear wings because they caused more drag than they were worth.

Even now days, the rules-limited underbody (in F1 and Champ Cars) provides the majority of the downforce. The front/rear wings are simply used to balance the car's grip front-to-rear.

[bh]

True, in terms of lift to drag. But remember, we are talking about FSAE, where the average track speed is around 30mph. Our goal at FSAE is to first maximize downforce, and secondly minimize drag. The first priority heavily outweighs the second. Until we get into the ~45+ mph range, the drag does not significantly slow the car (we are still traction limited in corner exit at around those speeds).

Obviously there is a limit to just how much drag you can have before it does become a drawback. We have not hit that yet, even during autocrosses, where average track speed is more like 45-50mph. So far, the more downforce we make, the faster the car and the easier to drive it is.

[riff_raff]

bh,

If you're running at less than 45 mph and you're still "traction limited" in the corners, you need to talk to a cart racer regarding set-up. Cart racers (especially shifter carts) are used to dealing with stiff (or no) suspensions and "peaky" power curves from their highly tuned 2-stroke engines. Those 250cc Superkarts are capable of breaking traction in all 6 gears, so mechanical grip is very important.

And of course you're right, it's very difficult to make significant downforce from any aero device, wing or tunnel, at 30 mph. And I'm sure you know, from your Aero 101 class, that drag losses increase at the square of the speed. So ditch the aero devices, soften up the rear springs and re-tune the engine to give as wide a power band as possible.