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Did Maurice Olley just do IFS for the stylists?


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#1 mariner

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Posted 22 April 2012 - 21:24

I think this post is dedicated to our old friend Cheapracer who beleived the only real axles were ones with wheels on each end.

I dont agree with that but I was reading Maurice Olley's autobiographical book and was struck by how much the beam axle problems he sought to eliminate with IFS were , perhaps, peculiar to those times .

He studied precession and wheel hop in great detail at Rolls Royce but MAYBE a lot of the problem was due to the very large diameter wheels used then, the heavy tyres and the short length of the classis king pin swivels which wore quickly and then couldn't control the shimmy forces properly

Possibly with todays small wheels , lighter tyres and widely spaced ball joint pivots the precession and wheel hop problems with beam axles would be far less seriuos

What IFS did do was hugely help the stylists and packaging engineers by allowing the engine to go between the front wheels and sit low down. I do wonder if that was a big factor in Olley's development of IFS , he did work for Alfred P Sloan's GM after all.

I am not going to say the Range Rover was perfect for road ride and handling but it was pretty good thanks to Spen King's detail design so you can't say beam axles can't work on road cars when engine location is not such a benefit to IFS.

So, with modern F1 cars having virtually no suspension movement and upward sloping wishbones etc would beam axles still make sense in racecars where styling etc. is not relevant.

I know nobody has ever made beam axles work on road racing but I am stlll not sure what the really fundemental barriers are

Edited by mariner, 22 April 2012 - 21:26.


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#2 carlt

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Posted 22 April 2012 - 21:50

If your being specific to the front axle -
weight and lack of camber gain would be two reasons

#3 Magoo

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Posted 22 April 2012 - 22:47

I don't have Olley & Milliken at hand at the moment but from memory it seems to me that from Olley's perspective two of the big issues driving IFS were 1) pitch and 2) front axle tramp/shimmy. I should avoid asserting anything without referring directly to the book as there is usually more going on than there may seem... which is part of its charm.

This is also a good time to mention that Bill Milliken celebrated his 100th birthday last week. Happy birthday, Bill.

#4 maxay1

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Posted 22 April 2012 - 23:05

Bill,

you are correct with regard to Olley's perspective on what drove IFS, but last week was Bill's 101st birthday! His engineering autobiography is a must read...

#5 Greg Locock

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Posted 22 April 2012 - 23:36

Gyroscopically introduced steer inputs due to excessive camber gain were still of interest in the 60s, and we occasionally see a shimmy introduced due to them even now. Of course this is usually masked by the PAS, and steering systems are generally far less clunky than they were back then, ie less backlash and stiffer.

I think more generally Olley demonstrated that a beam axle at each end tends to give insufficient understeer, with the technology of the day. IFS was his solution. But that is from memory.








#6 gruntguru

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Posted 23 April 2012 - 02:26

If your being specific to the front axle -
weight and lack of camber gain would be two reasons

I am pretty sure a front beam could be designed with similar unsprung to a good IFS.

Can anybody give me a typical value for nett camber gain (camber gain minus roll angle) for an open wheel race car? Seems to me a beam axle wouldn't suffer too much on this criterion.

#7 Magoo

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Posted 23 April 2012 - 02:43

Gyroscopically introduced steer inputs due to excessive camber gain were still of interest in the 60s, and we occasionally see a shimmy introduced due to them even now. Of course this is usually masked by the PAS, and steering systems are generally far less clunky than they were back then, ie less backlash and stiffer.

I think more generally Olley demonstrated that a beam axle at each end tends to give insufficient understeer, with the technology of the day. IFS was his solution. But that is from memory.


My memory may be questionable as well, but I believe Olley rather elaborately distinguished between classic beam axle shimmy and other forms that IFS may fall prey to like caster wobble. They seemed to adopt the view that only beam axles can beam axle shimmy and everything else was See Other. Time for another reading -- it's one of my favorites.



#8 Greg Locock

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Posted 23 April 2012 - 04:48

I don't have Olley's book, but I know this is discussed to some extent in Bastow. I really should get Olley.

#9 carlt

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Posted 23 April 2012 - 07:43

I dont agree with that but I was reading Maurice Olley's autobiographical book and was struck by how much the beam axle problems he sought to eliminate with IFS were , perhaps, peculiar to those times .


What time period were these developments occurring

#10 rachael

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Posted 23 April 2012 - 08:07

I don't have Olley & Milliken at hand at the moment but from memory it seems to me that from Olley's perspective two of the big issues driving IFS were 1) pitch and 2) front axle tramp/shimmy. I should avoid asserting anything without referring directly to the book as there is usually more going on than there may seem... which is part of its charm.

This is also a good time to mention that Bill Milliken celebrated his 100th birthday last week. Happy birthday, Bill.


Don't be put off by the title (Equations of Motion), Bill Milliken's autobiography is a truly brilliant book. Happy Birthday Bill!

#11 mariner

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Posted 23 April 2012 - 09:24

I have to confess I only read Olley's book quickly in the reference library but he did a lot of work on large diameter rollers with bumps to stimulate hop and shimmy whilst at RR.

Thinking a bit more there were two interlinked things which may have driven him to IFS.

- The cars of the time had long wheelbase so needed large front wheel angles for decent lock. This forced the front springs close together so reducing roll stiffness for any given bump rate.

- His K^2/AB ratio work pointed to having lower bump rates at the front versus the rear for best ride ( which was lets face it more important to GM than racecar handling).

So He couldn't ever get a low enough front rate without very low front roll stiffness as long as the beam axle used leaf springs.

Once the stylists realise that they could get better looksand more pasenger space from IFS as well as softer ride it was a no - brainer to go IFS

today we can arrange the effective spring base of a beam axle to be the track width and , for racing , front to rear spring rates are not ride optimised.

As an aside front beam axles do have many probems but one advantage is that you can choose almost any RC height without compromising camber change etc.




#12 Magoo

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Posted 23 April 2012 - 11:00

Bill,

you are correct with regard to Olley's perspective on what drove IFS, but last week was Bill's 101st birthday! His engineering autobiography is a must read...


Thanks. I've never been happier to receive a correction.

It's funny... now that you mention it, I clearly remember wishing him a happy 100th birthday here last year. Clearly, Bill's faculties remain sharper than mine.

#13 Bloggsworth

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Posted 26 April 2012 - 07:55

I give you the Beagle F3 car designed and built by Jim Yardley - It didn't work.

#14 gruntguru

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Posted 26 April 2012 - 22:51

Would you expect it to, with a name like that?

#15 Wolf

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Posted 27 April 2012 - 00:03

I give you the Beagle F3 car designed and built by Jim Yardley - It didn't work.


This one didn't set the world alight in '56, either. Mind you, maybe it had too much going on, with transversely mounted straight 8 in the rear, solid front axle and conventional de Dion at the rear... (BTW, it's Bugatti Type 251)

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#16 desmo

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Posted 27 April 2012 - 01:04

Just as easy to blame the mid-engine as the solid axle.

#17 Wolf

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Posted 27 April 2012 - 01:32

Haha, didn't mean it that way... but they knew what they were getting into with solid axles (I think they were a company trademark of a sort), whereas they were getting into unchartered territory with engine (am I correct in remembering that the only other transverse engine in F1 was Honda's 1.5l V12?).

Come to think of it, it came in quite interesting period- desmodromic valves, direct injection, engines as stressed chassis members in F1, airbrakes and wings sprouting on sportscars... :stoned:

#18 Kelpiecross

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Posted 27 April 2012 - 10:47

I give you the Beagle F3 car designed and built by Jim Yardley - It didn't work.


The rear-engined Beagle looks like a very neatly designed little car to me - and it seems to have been very successful in racing.

#19 Powersteer

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Posted 27 April 2012 - 20:43

Jean Bugatti inspired car that one? Creative set up like a Miura.

:cool:

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#20 mariner

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Posted 07 July 2012 - 16:17

I am resurrecting this thread because during my annual trip to the Goodwood FOS I got talking to Malcom Ricketts who now owns the Lotus 58 "beam axle " car.

The Lotus 58 was the last attempt ( I think) where a major racecar team tried to see if beam axles could work. It was a unique monocoque designed by Martin Wade for Lotus. It was a dual purpose F2/F1 chassis for either a 4 cylinder FVC or 8 cylinder DFV engine so it was really oversized for F2.

The rear end was a conventional De Dion system using a tubular frame to tie the rear wheels together whilst avoiding all the std. Hewland box and ancillaries bits.

The front end was a beam axle with the rack and pinion mounted on the beam axle to avoid any arc onflicts. So the column moved a bit as the axle and rack rose and fell. Four trailing links located the axle fore and aft ( very Cheapracer!).

The lateral front beam location is a simple peg and slot arrangement that would look familar to a 50's Maserati 250F mechanic! So no clever lateral links at all but the roll centre is fixed a a constant height above the ground.

The car was tested by Graham Hill in April 1968 who thought it slow. So Lotus put it away until " Jim gets back from Germany" - The sad part is that , of course, Jim Clark never did come back from Germany so the car was abandoned whilst Lotus tried to recover in 1968.

The car was broke up and stored at Hethel but eventually Classsic Team Lotus rebuilt it from the bits. Eddie Dennis , the original Team Lotus mechnic who built it up did the rebuild so it ought to be authentic!

Malcom Ricketts related that when he first tested the car after its rebuild it was " undrivable" because the front springs were to soft and the rear almost solid. That was fixed but its handling never made him and the other amateur drivers comfortable so it is now only used in demo. runs.

However the one thing he did say was that gyro kickback is definitely not a problem.

So an interesting car which seems to confirm that for racing a front beam axle isn't anything superior to IFS.

One funny story is that Classic Lotus and Malcom Ricketts were never sure why certain things were designed that way as Martin Wade had left Lotus and gone to the USA. Then at the Lotus 50th meeting at Snetterton a older person said " it looks just like it was " - the person was Martin Wade who had made as special trip to see his old cars.

more here

http://www.telegraph...-revisited.html

http://www.flickr.co...h27/7500116250/

http://www.f1fanatic...u-58-good-2012/

#21 Greg Locock

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Posted 08 July 2012 - 00:12


You get the gyroscopic kickback proportional to the absolute roll velocity of the axle. generally wheel vertical velocities are rather less in racing cars than road cars.

The nearest thing a racing car sees to a typical road car event is coming off a kerb, and a bit of a kick from the steering wheel is well within acceptability.

If someone has a damper velocity histogram for a circuit car it would be interesting to compare road and circuit values. FWIW I get 6 m/s wheel velocities.

#22 Johan Lekas

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Posted 08 July 2012 - 09:39

...
The lateral front beam location is a simple peg and slot arrangement that would look familar to a 50's Maserati 250F mechanic! So no clever lateral links at all but the roll centre is fixed a a constant height above the ground.

Pictures and discussion in the nostalgia forum
http://forums.autosp...showtopic=92104

The front lateral arrangement does not look like a peg and slot.

The "tip" of a horizontal triangle attached to the front axle comes through the bulkhead. A triangle pointing down holds the tip of the first triangle (and the front axle) laterally. This works together with the four-link without bind
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#23 Johan Lekas

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Posted 08 July 2012 - 09:42

In the http://forums.autosp...showtopic=92104 thead there is also an interview with Chapman from Road&Track:

Bulmer: It is fairly well-known that you have been experimenting for some time with a car with quite different suspension-in fact with beam or the equivalent at both front and back. Can you say how this is shaping

Chapman: Well, it's still very experimental-we've been running it on and off when we've had the time this year. In places it behaves incredibly well but we rather clouded the issue by deciding to build a Formula 2 car initially simply because we had Formula 2 engines to spare. The initial response was tremendous-we went out and ran so much quicker than we'd ever run before the first time out that it was unbelievable but then we tried it on faster circuits and found that really the car was a bit too big-we were gaining on the turns but losing on maximum speed and this clouded the issue for a bit.

Bulmer: Was it a consequence of the type of suspension?

Chapman: No, it's a very big car because we'd designed it to be capable of taking the Formula 1 engine and also it has the wedge shape. But we had such a frantic season building and rebuilding team cars that we've only just got back to normal development on the beam axle car. We've now put a Formula 1 engine in it and we're doing a test program on that but we've only just started so I can't tell any more really.

Bulmer: Have you tried it on a really bumpy surface?

Chapman: Oh yes, well we've run it at Snetterton which is as bumpy as most and it behaved very well.

Bulmer: No steering problems?

Chapman: No. The thing that I was really worried about was the steering problem and it just hasn't appeared at all. The biggest problem is roll because we've got very low roll centers -we tried to run it without anti-roll bars but the roll was enough to use up too much of the suspension travel. We've only got about 6 in. of suspension travel at the front-we made a mistake there. And when Firestone changed all their tire diameters we lost another inch because of ground clearance.

Bulmer: You've got the old beam axle problem of an effective spring base which is much narrower than the track.

Chapman: Yes, and we've also got a very high pitch oscillation on it, very high; even though we're running fairly high spring rates, we're still getting far too much pitch.

Bulmer: Have you got the springing harder at the front than at the back?

Chapman: No, we're running at frequencies of about 100/105 laden or something like that which is different from a year ago -we had it all very soft then but we've still got too much roll and so we're just putting anti-roll bars on now.

Bulmer: I can't see any disadvantage in that really.

Chapman: No, well we were trying to get away without them. So then we tried to cut the roll down by raising the roll center and that definitely reduced the cornering power so we've now gone back to the low roll center with roll bars. It sounds easy but in fact with the particular configuration of the car it's not very easy to put them on-it's the old, old story: we should have designed them in in the first place. So we're cobbling some on at the moment and then we'll see how it goes.


Edited by Johan Lekas, 08 July 2012 - 09:46.


#24 Magoo

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Posted 08 July 2012 - 11:24

Is there any information regarding the weight savings, if any, over a conventional wishbone setup?

#25 mariner

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Posted 08 July 2012 - 11:31

Thank you for the links, the pics seem to 100% contradict what the car owner said!!

Sounds like we are in Nostalgia forum territory so I'll give in - I wonder if the axle location method was changed at some time?

I would note that in true F1 tradition much of what Chapman said is different from the memories ascribed to Eddie Dennis who built the car!!

Doesn't mean Chapman was wrong but I can see why the restoration team wanted to find Martin Wade.

#26 Tony Matthews

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Posted 08 July 2012 - 13:47

Cheapy has some info and a video of his beam in the last post of this page ....
http://www.locostusa.......7&start=120

#27 saudoso

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Posted 08 July 2012 - 15:55

Link's broken Tony...

#28 Tony Matthews

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Posted 08 July 2012 - 16:14

So it is. We will have to wait and see...

http://www.locostusa (DOT) com/forums/viewtopic.php?f=53&t=9417&start=120

Try that!

Edited by Tony Matthews, 08 July 2012 - 18:17.


#29 Powersteer

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Posted 09 July 2012 - 05:27

Very interesting that Lotus dropped roll-center so that on bumpy surface the car would not move sideways as much. I am pretty sure they had a Dedion rear set up. Also, with how hard they run spring rates in racing, unsprung mass might not be an issue..the J-Damper is a good example, engineered to road surface unsprung mass.

:cool: