Formula1 Steering Question.

[autobonrun]

During today's Hungarian race, one of the camera shots showed an angle from behind the driver that included the front wheels and steering wheel. It appeared that a full turn to the left caused the right wheel to respond fully but the left wheel responded much slower and much less (nearly stayed straight). Likewise, a full turn to the right caused the left tire to turn and the right tire to remain nearly straight.

Was this just the way the camera made it appear or do the wheels actually turn at different angles and rates? If so, what advantage would be gained by keeping the inside wheel nearly straight?

[pbs911]

I would guess that what you are seeing is the deflection in the outside tire making it appear it is turning more. F1 has some prety tall sidewalls that results in lots of tire deflection when cornering. The inside tire is unweighted so the deflection is not as prevelent. (Is deflection the right word here?)

[surflvr911sc]

What you are seeing is correct. The geometry of the steering purposely makes the outside wheel turn more than the inside wheel. B/C the outside wheel is farther from the center (picture turning in a circle) it needs to turn sharper for both wheels to reach the same distance at the same time. Toe-in also helps in this. You car does this too.

Maybe one of the experts can explain it a little better than I did.

Did I get this backwards? The inside tire turns tighter for the smaller radius. I think that's right. Well I guess I don't know why the F1 inside tire doesn't turn much.

[David Ceruti]

Yes, this is called Ackerman angle and is due to the fact that the radii of the circles followed by the two front wheels is different and each will then have a different steering angle.

The actual angles used are normally not "perfect" Ackerman to allow for the slip angles of the wheels and the different weights on each wheel when cornering. Generally the inner wheel will be turned more so that it will generate more slip and hence more turning force when cornering - that is why you hear wheel scrub when turning sharply at low speed e.g. in a parking lot.

hope this makes some sense - if this is unclear, I will try to do a picture

[surflvr911sc]

I just looked up "Project 60 - Alignment on your 911" in "101 Projects". Wayne gives a good explanation of all the alignment parameters and why. I was wrong at first, inside tire turns tighter through the turns, which make sense now.

So I have absolutely no clue why the inside tire appeared to hardly turn at all. Big help I am. I guess F1 cars are just totally different animals.

[autobonrun]

This is why I'm confused with the F1 steering. The outside tire turned and the inside remained fairly straight which is just the opposite of what you guys are saying and is opposite to what David stated about the Ackerman angle. Maybe tire deflection could be part of it but I don't think it would explain the magnitude of the difference I see. The outside tire turned faster and ended up at a much more severe angle.

I used the frame by frame feature on my VCR to slowly advance the picture to double check what I was seeing. Although you could see it on tight turns, it was most apparent on a straight stretch when one of the drivers was making quick side to side turns to warm his tires up. Virtually, only the outside tire did the turning. In addition to knowing why, I would love to find out technically how they do this. I know on our cars, the angle of both tires is a function of the steering rack and the tie rods. It obviously doesn't hurt the F1 cars' ability to handle, as none I've ever seen respond like these F1 cars.

[David Ceruti]

This has been bugging me for the last two weeks - Needless to say I will be glued to the TV this Weekend

My gut feel is that the camera angle may create the appearance that the inner wheel doesn't turn much because it would create huge amounts of understeer

Note for autobonrun: It is relatively easy (theoretically at least) to change the Ackerman angle- All it involves is moving the steering rack back or forward relative to the steering arm ends. This changes the angle of the tie rods ends and affects how the much a given amount of movement in the rack will move each of the steering arms

Lets exchange ideas again after the race

BTW who do you all support? (If the answer is Michael Schumacher I don't want to know)

[Joeaksa]

David,

I would love to see Villeneuve get in a good car for a change and be able to go head to head with Montoya and Mikey. Those two, along with some of the other new guys could really put on a challenge if they were in a car that is close to the level of the Ferrari. We have all seen what Montoya has done when the Williams is working well and he seems to have no fear what so ever...

The only reason why Mikey has won so many races was that Senna was not there to wipe the floor with him like he did when he was alive... Schumacher is good but what got him there is the combination of the car and planning he has to draw upon.

Joe

[RazorRacer]

The real racing is in the middle of the pack. I'd like to see team Toyota do well. They have the resources to make a difference.

It's boring watching Ferrari, BMW, Mercedes in that order every week.

There should be two broadcasts. One that shows the leaders and another that shows the middle.

Anyone going to the Indy F1 race?

[Paul Franssen]

Mikey? It took me a while to figure out who that micht be... of course, you mean Michael, Sir! Mikey is something for Americans, not Germans! And in the case of Mr. Schumacher, I would say Mike, certainly not something tending to diminish. And Mr. Senna, he Sir, is not around. And the Canadian, he just blew his engine and then hit the (sand)pits. And Mr. Juan-Pablo, he's looking every day a bit more like the Pope. Did you see Michael Schumacher qualify today at Spa? Settled that, right there and then. I'm rather pleased Mr. Panis got himself a ride with Toyota for next year: the only way to go is up, and Toyota are aiming for just that.

[Mike M]

I don't know about the Ackerman angle,but I've been a TV cameraman for 17 years and I can tell you that the "point of view" cameras they use for these shots have extremely wide angle lenses. A wide lens will cause distortion,sometimes called fish-eye. When the camera moves or something in the camera shot moves,very weird things appear to happen. This may be why one wheel appears to turn more that the other.

[David Ceruti]

Well well - seems that my comments about Sir Michael raised a few opinions. He is undoubtably a very good driver but I what I dislike about him is that he is a perfect example of the kind of modern driver that sponsors love - bland, always the diplomat and so single mindedly professional that he seems like a robot. He even makes Senna seem to have been a character. I guess I like drivers that are a bit more "human" - who show passion, and fire and stuff it up from time to time. Like Rosberg, Berger, Mansell and of the present crop Montoya and Villeneuve.

Oh I would love a Rossi in F1!!

I actually met the Schumie brothers back in the early eighties when they came out to SA to race Karts. Can't say that I remember much - just that they were both bloody fast, bloody ambitious and had a daddy right behind them.

Hope I haven't started a bun fight with this one:eek

Ah well - lets see what happens to-morrow:

[Bob Goding]

On the subject of F1,maybe someone out there might have a satisfactory answer to an observation that has been puzzling me for a long time. A couple of years ago we had one of Shuie's
Ferraris at a motor show here in NZ and I asked a rep. at the stand. --Then earlier this year we had the retired manager of Maclaren on talkback radio and I rang and asked him. The reply was all fluff.
-------So, Why dont F1 cars run low profile tyres?

[Zeke]

Originally posted by Bob Goding

-------So, Why dont F1 cars run low profile tyres?

With as much downforce as the F1 cars have, suspension travel is virtually usless. It has to be stiff enough to hold the car up when something like 5000lbs is pushing it down. At low speeds, this amounts to basically solid suspension. The tires are the suspension and therefore have to be tall enough to absorb the shock that typical suspension does. Also, the faster they turn, the more they grow and hold the car up. In the days of active suspension, this could all be programmed into the suspension computer, i.e., softer settings at slower speeds and conversly, tighter at higher speeds.

It's also a function of the rules. Tire widths and heights along with the grooves are all intended to keep the cars speeds down. There would still be a rule against traction control, but the scrutineers gave up trying to police it. Too many ways to implement TC without it being noticed. Any time you have electronics governing intake and ignition, the possibilties are limitless. It is highly suspected that Nascar has some teams that have some form of subtle TC. The tech inspectors now even count the number of wires on the car to make sure they know what each one does.

[David Ceruti]

Watching the the slow motion shots at the bustop at Spa on Sunday it seems that the inside wheel did turn in more than the outside. I was hoping to get a good look at a stationary car but either I was drowsing (late night on the P-car) or there wasn't a good shot.

Speculating about the engineering, the downforce on F1 cars is such a big part of the equation that weight transfer won't unload the inside wheel as much as on a saloon car so I would imagine that the steering geometry will be closer to true Ackerman on F1 a car

I also share Bob's puzzlement on F1 tyres though. I take Zeke's point about the possible regulations, but I don't buy using the tyres as springs to counter the downforce because the tyres "springs" are essentially undamped. I also can't see a steel belted tyre growing significantly under certrifugal forces. This is all just guesswork - I would really like to know. Maybe a thread in one of the other areas or does anyone know of a good F1 BB

[Roland Kunz]

Hello

@ Joeaksa

Schumacher and Senna had some "fun" togehther.
I think if Senna still would turn circles things might developed different. But Senna could be beaten and showed nerves if pushed.

Mr. Schuhmacher is in fact born and educatet in germany but he pays his taxes in switzerland

Your homeland is where you pay your taxes

Low profile tires ? ask your local dragster driver why he didn´t use them

Grüsse

[Zeke]

David, I knew someone would catch me on the "growing" thing. You are right, the tires don't grow in diameter like a dragster tire. But undamped ao not, the tires are the big part of the suspension. Even in stock car racing, a half a pound air pressure adjustment is said to change the overall spring rate.

Back to the growing thing. What I theorize here is that the treaded portion of the tire (the circumference) behaves differently when spinning at high speed making it less likely to collapse under the weight of the downforce, so it grows to a truer circle with less contact patch. How's that for getting out of a tight spot?

[David Ceruti]

Zeke

I wasn't trying to catch you out - Its just that this question has been bugging me for a while and I tend to obsess on this type of technical trivia. Your input got me thinking - I am not even sure if F1 uses steel belted tires - I know that they were using crossplies a few years ago - the mystery deepens!!
I went onto the FIA site to look aththeir regulations ans found this:
Wheel diameter must not exceed 660 mm
WWheel bead diameter must lie between 328 and 332mm

This would result in a sidewall height of around 155mm.

So a team would have the option of running a large tyre with high sidewall or a smaller low profile tyre. Still doesn't answer the question of why the FIA has the regulation like this at all

It seems some concentrated research is called for. If I get any answers I will post them here

Stay well and enjoy Monza

[Paul Franssen]

(rather off-topic, but better to say) to David Ceruti: kind greetings to you, my nerves are flaming my temper (has a lot to do with my Carrera being delayed n repairs) Re Schumi and co. I'll agree no 2 races can be compared... 'ave a Pinotage on me!

[David Ceruti]

Paul

Even more OT.

Where did you learn about Pinotage and Thanks - Ive got a nice bottle of '85 Kanonkop that has just been waiting for an excuse to be opened

If you are interested, there are a few nice sites that sell SA wine online. E-mail me and I'll send you the URL

Stay well

David