Vettel's Steering Issue

All that has to do with the power train, gearbox, clutch, fuels and lubricants, etc. Generally the mechanical side of Formula One.
Tommy Cookers
364
Joined: Fri Feb 17, 2012 3:55 pm

Re: Vettel's Steering Issue

Post by Tommy Cookers » Sat Aug 05, 2017 9:04 am

[quote=Zynerji] ........I wouldn't expect those to be outrageous numbers. They run 4 degrees of camber as well...[/quote]

we could say that they don't 'run' 4 degrees of camber

the camber is eg 4 deg negative in a stationary or slow-moving car ie in unimportant situations
because that's how to get in hard cornering the (outside) wheel acting at '0 deg' - ie normal to the track 'horizontal'
this might only be due to tyre compression effects as there appears to be little or no geometric effect producing traditional 'camber gain'
also the buildup of DF is a factor

maybe toe also changes similarly
but we should agree whether eg front toe is in or out and rear toe is in or out - and why

Zynerji
5
Joined: Wed Jan 27, 2016 3:14 pm

Re: Vettel's Steering Issue

Post by Zynerji » Sat Aug 05, 2017 7:12 pm

I'd like to know as well. He was an alien driver, and he did a weird "stair step" type cornering, very little Button, and far more Raikkonen.

But I helped with his setups for 5 years, and he won several championships in that time. The tyre wear was always the most important, and the 3-4 negative in the front and .5-1 positive in the rear allowed him to drive like that. This was done over rF1, rF2 and AC, so not a single sim engine.

I always thought it had to do with the weight transfer spikes generated by the stair step corner entry. It was destroying the tyres at first, but through the corner dampers and the toe, we found the balance. In most races, he was literally able to hold an entire gear higher to "shimmy" through most corners.

But Sims are not real, so it would be interesting to hear from the suspension guys here, as that is their wheel house.

Jolle
58
Joined: Wed Jan 29, 2014 9:58 pm
Location: Dordrecht

Re: Vettel's Steering Issue

Post by Jolle » Sun Aug 06, 2017 1:12 pm

Ok, what we more or less know: the issue wasn't there on the parade lap, the moog block was changed, the connection from steering wheel to wheel is all mechanical, there was no excess tire wear, in PF and they wanted both of them (RAI and VET) to stay off high curbs.

The only thing I can think of that there was a shift in one of the steering shaft connections, possible on the rack itself. Like someone didn't secure the rack enough and with small tolerances, pulling the steering wheel off on the grid and the wheels up in the air, it got out of place just enough to "hop" a few notches.

gruntguru
330
Joined: Sat Feb 21, 2009 6:43 am

Re: Vettel's Steering Issue

Post by gruntguru » Mon Aug 07, 2017 5:15 am

Mudflap wrote:
Thu Aug 03, 2017 11:08 pm
gruntguru wrote:
Thu Aug 03, 2017 4:28 am
wuzak wrote:
Wed Aug 02, 2017 7:26 am
From what I understand the power steering systems are hydraulic.

Fears in the early 2000s were that the electrically assisted systems could aid the driver in knowing when to steer, by having little or no assistance when steering was not desireable or by having more assistance when it was required.

The cars knew where they were on track through transponder and other electronic systems.

Edit: Found the regulation (2013 don't have later on this PC)

10.4.2 Power assisted steering systems may not be electronically controlled or electrically powered. No such system may carry out any function other than reduce the physical effort required to steer the car.
Yet another dumb regulation. (No need to specify non-electric.)
I think that's to prevent teams from developing fancy computer assisted steering.
Which is exactly why I said it is dumb. They don't think computer assisted steering could be done with hydraulics?
je suis charlie

wuzak
285
Joined: Tue Aug 30, 2011 2:26 am

Re: Vettel's Steering Issue

Post by wuzak » Mon Aug 07, 2017 7:03 am

gruntguru wrote:
Mon Aug 07, 2017 5:15 am
Mudflap wrote:
Thu Aug 03, 2017 11:08 pm
gruntguru wrote:
Thu Aug 03, 2017 4:28 am
Yet another dumb regulation. (No need to specify non-electric.)
I think that's to prevent teams from developing fancy computer assisted steering.
Which is exactly why I said it is dumb. They don't think computer assisted steering could be done with hydraulics?
Hydraulics not connected in any way to a computer, yeah.

outsid3r
6
Joined: Thu Nov 01, 2012 9:55 pm

Re: Vettel's Steering Issue

Post by outsid3r » Mon Aug 07, 2017 8:48 am

bigpat wrote:
Fri Aug 04, 2017 1:55 pm
Generally if something is left loose, it gets worse. I don't think it's toe movement from kerbs, remember carbon suspension doesn't permanently deform, its intact or in pieces. I think that now in F1, shims/packers are used for suspension adjustment for better installation stiffness.

I think the electric power steering went AWOL. I would think there is a rotary potentiometer to indicate steering angle, to determine the amount of assistance for the amount of steering lock applied. If an adjusting bolt was left untightened then it could give an incorrect reading as to where the centre would be, and could get worse, which is what Vettel reported....
I wasn't referring to the carbon parts as such - like you said, they would either be in one piece or a million pieces. I was thinking of the part where they fine tune the toe angle. On a road car it would look something like this:

Image

...and if left loose, kerbs would definitely cause it to change dimensions. Then again, I would imagine that an F1 car wouldn't have a primitive system such as this one, hence mine is only a speculation

bigpat
16
Joined: Thu Mar 29, 2012 12:50 am

Re: Vettel's Steering Issue

Post by bigpat » Mon Aug 07, 2017 12:54 pm

Ok, So I was wrong on electric powered steering!!!!, I still I suspect there was a failure on the centering...

As for toe settings, a typical race car will have static toe out to assist turn in response. Road cars run toe in for stability.
Conversely toe in is run at the rear of a race car to settle the rear end down.

On our Formula Holdens ( Euro F 3000's ) we typically ran a total amount of 6-8mm toe out up front, and between 4-8 mm toe in rear. Cambers were on avg 2.5 - 3.5 degree neg front, and 1.5 degree rear. We typically ran 5 degrees of castor, though we did play with less. The drivers liked the reduced steering load from that....

Watch Damon Hills qualy lap from the 1997 Aust Grand Prix to see what happens when a mechanic accidentally puts toe out on a race car....

As for the toe adjuster, yes most racecars use LH & RH threaded adjusters, though I have seen splined setups for both toe and camber adjustment...

bigpat
16
Joined: Thu Mar 29, 2012 12:50 am

Re: Vettel's Steering Issue

Post by bigpat » Mon Aug 07, 2017 1:07 pm

Might be of interest here...

F1 Power Steering Rack
Posted on June 21, 2016
WF1-Rack- (7)

Much like the shift in road car steering, F1 steering is now power assisted, with the hydraulic power steering rack now has been standard for many years. Integrated as part of the cars high power hydraulic system, the rack is an essential part of the cars set up. Without it the current suspension geometry at the upright would be impossible to steer without power assistance. Like all F1 hydraulic solutions, the rack is a simple solution, made possible by finely engineered details.

WF1-Rack- (1)

Operated in classic racecar fashion, by a steering column acting on a rack and pinion set inside the rack’s body, the basic mechanics of F1 steering are simple. A kind of chicken and egg situation has grown up around the upright geometry with increasing offset being used to provide feedback at the cost of the mechanical effort to require to steer the car. Power steering allows the geometry and as a result the geometry becomes even more exaggerated, both sides driving each other. Now an F1 car is un-drivable without power steering and to some extent easy because of the power assistance, allowing the drivers to be of slimmer build.

WF1-Rack- (3)

The hydraulic process is also simple, a double acting piston is supplied with a pressurized hydraulic fluid to aid the rack and pinion move in either direction. The hydraulic fluid is supplied as part of the cars main hydraulic system, from a pump driven by the engine. The FIA regulatory requirement for the steering to be a simple hydro-mechanical system, means that no electronics are involved in the process, so none of the Moog electro servo valves are used. This makes metering the fluid flow and tuning the system to the driver’s demands, a tricky exercise in the detail design of the system. Perhaps in hindsight a SECU monitored electronic system would have been cheaper, than teams investing huge resources in mechanical engineering to tailor the system to each car\driver?

Moog Spool valves

Translating the drivers turn of the steering column into a precise fluid flow into the piston is the job of the spool valve. Despite being a passive mechanical part, it’s still often made by electro-servo valve supplier Moog. With movement in either direction the spool valve meters a pressurized supply of fluid to either side of the piston. To move the spool valve there needs to be a tiny amount of ‘give’ in the column to rack movement, this lost movement is translated to the spool valve and into the rack. This effect isn’t felt by the driver, such is the efficiency and accuracy of the spool valve, only a microscopic amount of movement is required.

To provide this give there are two ways to have the offset movement, in the column itself or in the rack and pinion interface.

WF1-Rack- (9)

I have a Williams F1 Steering rack, while its nearly complete the spool valve is missing, but it’s clear the system uses the column flex to provide the spool valve movement. The last section of steering column going into the rack is separate from the main steering column and a precision machined part of the rack assembly. The column shaft thins and a small angular flex is created in the shaft when steering movement is put into the system by the driver. This flex rotates a spool valve mounted around the column and this then sends proportional pressure change into the piston.

IMG_20151209_111038

Other racks use a flexure at the point where the pinion meets the rack. Rather than a solid mounting of the pinion into the rack body, there a “W” shaped flexure, when steering effort is put into the system, the pinions moves laterally a tiny amount. This operates the spool valve which then provides the proportional fluid control.

Both systems see active use in F1, with steering racks increasingly tucked away out of sight inside the front bulkhead, it’s not possible to see which remains the more popular solution and who has what set up.

This entry was posted in Uncategorized by scarbsf1. Bookmark the permalink.

ChrisDanger
38
Joined: Wed Mar 30, 2011 8:59 am

Re: Vettel's Steering Issue

Post by ChrisDanger » Mon Aug 07, 2017 3:52 pm

bigpat wrote:
Mon Aug 07, 2017 12:54 pm
Watch Damon Hills qualy lap from the 1997 Aust Grand Prix to see what happens when a mechanic accidentally puts toe out on a race car....
I haven't been able to find out the reason for the poor performance. Do you know for sure that the problem was definitely an incorrect front toe setting, that the setting was negative (toe-out), and that "normal" settings are positive (toe-in)? Please provide references if possible.

I did find this setup sheet for a 2001 Arrows A22 which has a negative front toe setting, but it looks like it's in clicks, not degrees, so who knows what the actual value is.

Image

Scootin159
10
Joined: Thu Aug 06, 2009 8:09 pm

Re: Vettel's Steering Issue

Post by Scootin159 » Mon Aug 07, 2017 7:07 pm

FYI - Most (if not all) F1 teams use shim packs for setting alignment settings. As opposed to the standard lh/rh threaded turnbuckles, they'll just unscrew one end of the suspension arm, slide in a shim, and tighten things back up. This design allows for much more repeatable adjustments, and has a much lower risk of things loosening up on track (not to mention being lighter & stronger).

That said - if the shim pack bolts were to loosen up, they could introduce some slop in the system. This would also be a huge safety concern though, as the added shock stress on the bolts as they are loaded/unloaded under normal suspension loads could easily cause them to break, and cause immediate suspension failure. The team probably don't have sensors on the shim packs themselves, but they may have been able to see that something was amiss by analyzing the standard pushrod load sensors.

The numbers in the Arrows setup sheet are probably index values for the shims to be used. The team engineers can quickly convert those numbers into degrees - but in reality they don't need to, they just know if they want to go up/down one or two steps. The mechanics also won't care what the actual degrees are, they just need to know what shim to use.

MrPotatoHead
18
User avatar
Joined: Thu Apr 20, 2017 6:03 pm
Location: All over.

Re: Vettel's Steering Issue

Post by MrPotatoHead » Wed Aug 09, 2017 2:15 am

This should be required reading for anyone in this discussion :-P

http://scarbsf1.com/?p=4585

Also:

http://www.moog.com/content/dam/moog/li ... _Valve.pdf

bigpat
16
Joined: Thu Mar 29, 2012 12:50 am

Re: Vettel's Steering Issue

Post by bigpat » Fri Aug 11, 2017 2:37 pm

That's the article I tried to copy onto my post. Good read....

As for Damon Hills lap in 97, there was toe out accidentally put into the rear end on one side.

In all the circuit and speedway racing I've been involved in, we run toe out to neutral on the front, and straight to toe in at the rear. It works, simple....



Who is online

Users browsing this forum: CCBot [Bot], Yahoo [Bot] and 6 guests