steering wheel torque - how much do drivers cope with?

[fiohaa]

i would like to know how much steering torque in NM do drivers have to cope with when driving? Either F1 or GP2?

reason: waiting to buy a servo motor wheel for my racing sims, one is capable of 7nM, the other 2 are more expensive but capable of 10-14 NM.

Just wondering if 7 is enough, or whether I need to get the more expensive wheel for a more true to life force.

thanks.

[fiohaa]

well i found this http://www.sae.org/students/cockpit_control_forces.pdf
One of the Design Judges (Steve Lyman aka ‘Ergo Man’) was kind enough to send along the
following data. This is static measured torque data he has acquired over the years using a Sensor
Development hand wheel torque sensor:
Autokraft Midget = 6.0 Nm (55 in-lbs) No power steering, 380mm (15.0”) Ø steering wheel.
Lola T332 = 5.5-8.5 Nm (50-75 in-lbs) No power steering, 318mm (12.5") Ø steering wheel.
Dodge Viper SRT-10 = 4.5 Nm (40 in-lbs) Power steering, 350mm (13.7" Ø steering wheel.
Lotus 20 = 4.0-4.5 Nm (35-40 in-lbs) No power steering, 330mm (13.0") Ø steering wheel.
Lola T190 = 6.0-7.5 Nm (55-65 in-lbs) No power steering, 318mm (12.5") Ø steering wheel.

I wonder if anyone has got any data for F1/Gp2?

[Scootin159]

F1 cars have power steering, so I would expect it to be entirely up to what the driver's preferences, but most likely inline with any other car they've driven on the path to F1.

[strad]

I have wondered how light the steering is myself.
I would think you would want it fairly stiff for the straights but lighter for the twisty sections. Is it a compromise or do they have a variable sort of thing like on my Caddy?

[Tim.Wright]

Assist is almost aleays added as a function of speed startingwith maximum assist at zero speed for parking and going to nearly zero at highway speeds.

5Nm is a typical maximum steady value when you are at the grip limit for a road car. It might be smaller (ie more assist) on an F1 car because the steerin)wheel is a smaller diameter and thee is more sustained driving in limit conditions.

[Greg Locock]

To add to Tim's post, even with HPAS the assist is a non linear function of the demand torque. So, for very small efforts say 1.5 Nm you get no assist and then at say 6Nm you'll get 25 Nm of assist. On road cars with EPAS some manufacturers use a parametric set of curves, others use lookup tables, and some use a mixture. There are many more functions available in EPAS than in the most complex HPAS, but I doubt they would be used when racing.

Here's an example of a boost curve, I don't know what they are trying to do but the dotted lines would feel a bit odd

http://patentimages.storage.googleapis. ... D00003.png

[CBeck113]

To add to Tim's post, even with HPAS the assist is a non linear function of the demand torque. So, for very small efforts say 1.5 Nm you get no assist and then at say 6Nm you'll get 25 Nm of assist. On road cars with EPAS some manufacturers use a parametric set of curves, others use lookup tables, and some use a mixture. There are many more functions available in EPAS than in the most complex HPAS, but I doubt they would be used when racing.

Here's an example of a boost curve, I don't know what they are trying to do but the dotted lines would feel a bit odd

http://patentimages.storage.googleapis. ... D00003.png

Not necessarily Greg: you also need the "center" feel to the steering, to know when the tires are straight - that's exactly why the curves start with such a steep slope before dropping the resistance for real steering actuation.

[yessamgerg]

Not an F1 car obviously but here is a log of steering torque, steering travel and wheel speed on our FSAE car. Let me know if you want any different graphs of the data and I should be able to provide it...

https://plus.google.com/photos/11787185 ... 5LiksdSuVg

[riff_raff]

To make the experience real, what you need is a way to simulate the cornering forces.

Regarding the forces required for steering or shifting, recall the effort required from F1 drivers 20 years ago. I remember seeing drivers get out of the car with holes worn through their gloves and blisters on their hands.

[andylaurence]

Not an F1 car obviously but here is a log of steering torque, steering travel and wheel speed on our FSAE car. Let me know if you want any different graphs of the data and I should be able to provide it...

https://plus.google.com/photos/11787185 ... 5LiksdSuVg

Interesting stuff. Does the car oversteer quite a bit at low speed? It seems more stable at higher speeds.

[yessamgerg]

Interesting stuff. Does the car oversteer quite a bit at low speed? It seems more stable at higher speeds.

Not really, this test was done at the end of a long test season right before leaving for our second competition so a this point the car was handling pretty much exactly as intended. do you have a spot that illustrates the question, I can go into the log and look at what else is happening, could be on throttle or something....

[BanMeToo]

I can't produce numbers but GP2 cars will take more effort to steer, compared to F1, since they lack any assist/power steering.

[fiohaa]

Not an F1 car obviously but here is a log of steering torque, steering travel and wheel speed on our FSAE car. Let me know if you want any different graphs of the data and I should be able to provide it...

https://plus.google.com/photos/11787185 ... 5LiksdSuVg

thanks, so how do i interpret the graph? its saying maximum torque achieved was 267 lbs.
What does this mean? Is that the amount of turning force being applied to the steering column? So that is what the driver is pushing against, with the steering wheel? (267 lbs = radius of steering wheel * force being applied by arms) ?!

[fiohaa]

ive found a video which has answered my question.

All sorted.
http://youtu.be/bynp2wiadKM

[yessamgerg]

thanks, so how do i interpret the graph? its saying maximum torque achieved was 267 lbs.
What does this mean? Is that the amount of turning force being applied to the steering column? So that is what the driver is pushing against, with the steering wheel? (267 lbs = radius of steering wheel * force being applied by arms) ?!

This was measured with a strain gauge rosette on the steering column shaft so this is the torque being applied by the driver. The steering wheel is right around 10" diameter so 267 in-lbs would be 27 lbs per arm (one pushing one pulling). The important thing here is that this is generally just during turn in and then quickly falls off during steady state turns. Generally the SS torque is ~100 in-lbs.