Driver position regarding handling perception

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j-c-c
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Driver position regarding handling perception

Post by j-c-c » Mon Jan 01, 2018 5:59 pm

Anybody seen/read data on how a drivers location in a car assists/hinders the drivers perception of how the car handles?
Related, is it the driver's head/eyesight/ear canal that determines perceived motions, or is the entire body a g sensor?
So back to the first question, is it the relationship to the COG that is most important, or some ratio between the fixed and steering axles?
Seems like this would be a big deal, but have yet to read a single thread discussing the topic online over the years.
Does one answer fit all cars and or drivers?
Seems like this would effect any human occupied driven vehicle.
I am not concerned here, on these questions, about how the drivers mass and its location effects the car.

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Re: Driver position regarding handling perception

Post by PackardV8 » Mon Jan 01, 2018 6:51 pm

For true, I've never read any authoritative quantified dissertations on driver location.

Speaking subjectively, I just experienced how much inner ear location affects vehicle dynamic perception. A '63 Studebaker Avanti has fixed upright seats and limited rearward travel. I replaced the OEM seats with some wrecking yard six-way-power-adjustable-heated-leather from a Japanese luxury car. The extra travel and recline relocated my inner ear almost a foot rearward and some inches lower. The driving experience feels like a completely different car.

I remember in the bad old days of transition from upright Champ Car front engine solid axles to rear engine independent suspension reclining, some very good drivers could not make the switch; couldn't feel what was happening in the laydowns.
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Re: Driver position regarding handling perception

Post by peejay » Mon Jan 01, 2018 7:40 pm

Supposedly one of the things that made the MkII Escort such a controllable driver's car is the driving position and its placement relative to the center of mass and the axle centerlines.

I keep requesting a drive in one, built to Group 4 rally specs, but so far nobody is offering me a drive :)

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Re: Driver position regarding handling perception

Post by PackardV8 » Mon Jan 01, 2018 10:10 pm

peejay wrote:
Mon Jan 01, 2018 7:40 pm
Supposedly one of the things that made the MkII Escort such a controllable driver's car is the driving position and its placement relative to the center of mass and the axle centerlines.

I keep requesting a drive in one, built to Group 4 rally specs, but so far nobody is offering me a drive :)
The Saab 99 is another genius design for rally cars. The driver can feel the car pivoting around him in the centerline. The seemingly similar later, longer 900s were numb by comparison.
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Re: Driver position regarding handling perception

Post by j-c-c » Tue Jan 02, 2018 11:23 am

I can't dispute any of the comments so far, but it would seem being close to a centerline (and we need? to differentiate between COG, center of pressure, roll center, etc) on any plane, would reduce rather then amplify motions, hard to understand which is better ( or the sweet spot) for driver perception.

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Re: Driver position regarding handling perception

Post by Speedbump » Tue Jan 02, 2018 12:40 pm

Can't say it relates to cars but in my AF career I've had the opportunity to ride back seat in a couple of fighters. The first, early in my career was an F-100 where the seats are almost 90 degrees to the airframe. We did a 5+G pull out after a simulated rocket attack and the feeling, to an inexperienced person, was pretty intense. At the end of my career I got to go in an F-16 where the seats are substantially reclined. At the end of runway the pilot said we would clear the runway and do a 6G rotate to vertical in a max performance climb. My mind went back to the 5G thing from the past and the anticipation level went way up. We did the maneuver and it was so smooth and easy I was convinced we didn't do the advertised G's. Checked the G meter and sure enough 6.1 G's but the difference in body feel was stunning to me. Needless to say, it was the ride of a lifetime. Guess it's like comparing a Model A to a Lexus.
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Re: Driver position regarding handling perception

Post by In-Tech » Tue Jan 02, 2018 12:42 pm

Speedbump = 8) =D>
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Re: Driver position regarding handling perception

Post by j-c-c » Tue Jan 02, 2018 4:10 pm

Actually the inspiration for my original question was by a book I was reading about military test pilots at Wright during WW2, and a comment one made about how pilot position in the plane effected flight perception characteristics. The pilot did not elaborate. They also touched on in much greater length testing of reclined seats for high g's during the end of Prop plane era as jets were being introduced, but strangely, nothing learned about reclined seating improving G force tolerance was applied until nearly 20? years into the jet era.

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Re: Driver position regarding handling perception

Post by Speedbump » Tue Jan 02, 2018 4:54 pm

Some of the greatest innovations are the ones where, when experienced, one says, "Hell, I could have thought of that", which was my thinking after the physics of it was explained by a pilot after the flight. I don't know how that may translate since the jet is trying to push you through the floor and a drag car is trying to push you out the back. My drag race experience has been exclusively with door cars and the fastest only a mid 9 sec SG car. I recently completed a build of a tube chassis altered where the seating is in the center as opposed to the left side. I don't know how to explain the difference but I can tell you there definitely IS a difference, not entirely to my liking.(experience?) I've only been sideways once in the door car and it seemed like a BIG deal to me. Broke a ladder bar bracket at the launch, did a pretty immediate right turn but there was no speed, so corrected and continued down the track and back to the pits. No one there seemed to think it was much of a deal which surprised me. In the altered on my second to last license pass I got a little out of the groove and the car wiggled at about 1000 feet. I felt it but didn't think too much of it. Got back to the pits and asked if anyone saw it or was it me. The reaction seemed to be bigger than what I felt in the car. So I wonder was what I felt part of driver position or just an older, nervous guy in a faster car? Kind of the same as your question. Does a 200 MPH pro stock driver feel a more magnified movement than a 200 mph alcohol altered driver when the rear starts to move?
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Re: Driver position regarding handling perception

Post by Brian P » Tue Jan 02, 2018 4:55 pm

I recall that there was an issue with a certain commercial aircraft that led to at least one crash, because the location of the pilots was such that if they bounced the main landing gear due to a slightly-too-hard landing, they were so close to the center of rotation that they couldn't feel that it had happened, which led to them cutting throttle and applying the air brakes while the plane was actually in the air after the bounce - and the subsequent really hard bounce was too hard and too late to recover from.

My van has the driver and passenger almost on top of the front wheels, which is the opposite of ideal driver position for feeling what is happening at the rear wheels. It's OK in that application, the rear suspension can be stiff for cargo capacity and it still rides OK because the driver mostly feels the front suspension.

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Re: Driver position regarding handling perception

Post by Kenova » Tue Jan 02, 2018 9:18 pm

Brian P wrote:
Tue Jan 02, 2018 4:55 pm

My van has the driver and passenger almost on top of the front wheels, which is the opposite of ideal driver position for feeling what is happening at the rear wheels. It's OK in that application, the rear suspension can be stiff for cargo capacity and it still rides OK because the driver mostly feels the front suspension.
I drove a full size GM van (12 passenger) for a number of years in all kinds of weather.
A little twitch in the drivers seat was enough to fling a 200 pound passenger from one side of the rear seat to the other. I thought it was funny as hell but he didn't see the humour in it. :lol:

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Re: Driver position regarding handling perception

Post by Morgo » Sat Feb 10, 2018 11:59 am

I have a -93 Camry STW with 3 litre V-6.Driver seat is about middle of the axels and is incredibly easy to drive sideways and steer with throttle.
Even on dry asphalt :D
Giving friends four wheel slide experience they are in extacy 8)
Yeah,just check how many Finns are WRC and F-1 champions (from population of bit over 5 million)
The ability to feel what the car is doing and how to mange it is maybe in the genes :wink:
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Re: Driver position regarding handling perception

Post by PackardV8 » Sat Feb 10, 2018 12:16 pm

Morgo wrote:
Sat Feb 10, 2018 11:59 am
Yeah,just check how many Finns are WRC and F-1 champions (from population of bit over 5 million) The ability to feel what the car is doing and how to mange it is maybe in the genes
Or maybe the roads are frozen ten months of the year, so lots of practice slides and no traffic and nothing to hit.
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Re: Driver position regarding handling perception

Post by MadBill » Tue Feb 13, 2018 10:11 pm

My driver/car location interaction story relates to my first time at the wheel of a RHD car, a Suzuki. I thought I was doing fine until I realized I was positioning my body in the usual location wrt the road centerline, leaving the bulk of the car in the oncoming lane! :oops:

Wake-up two was when I dipped the clutch and up-shifted the window crank.. #-o
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