117 replies to this topic

[saudoso]

You had better believe it, they teach English here that is at least 50 years old and I have trouble understanding what they say sometimes.

Also pick up a Sherlock Holmes book and see the grammar style and words used.

I was silly enough to go with my wife to see Henry VIII on Broadway. Being a non native speaker and all, I got sleepy to the point of explosive snoring. I could get one word out of four I guess.

[Greg Locock]

If the worlds fastest car Thrust SSC uses rear steering then there cant be much wrong with the idea.

The'thrust' from the engines in the LSR car helps to keep the car strait and prevents the application of the rear steering
from destabalising the car.

Probably the stupidest argument by analogy I have ever read on this board. Next up you'll be explaining why commuter cars should be powered by jet engines, cos they're used on Thrust.

Since you don't want equations, or simulations, build a prototype and prove your point. Or your ideas will continue to be mocked.

Not too sure why you put thrust in quotes, jet engines make thrust, not 'thrust'. Anyway, you are now at liberty to explain how, if a car deviates to the right, having the nozzle of a jet engine sticking out the back, is a stabilisizing influence. Would it not push the car more to the right? ThrustSSC does not have steerable nozzles.

[24gerrard]

Probably the stupidest argument by analogy I have ever read on this board. Next up you'll be explaining why commuter cars should be powered by jet engines, cos they're used on Thrust.

Since you don't want equations, or simulations, build a prototype and prove your point. Or your ideas will continue to be mocked.

Not too sure why you put thrust in quotes, jet engines make thrust, not 'thrust'. Anyway, you are now at liberty to explain how, if a car deviates to the right, having the nozzle of a jet engine sticking out the back, is a stabilisizing influence. Would it not push the car more to the right? ThrustSSC does not have steerable nozzles.

Mock away Greg if it makes you feel better.
The thrust from a jet or rocket will reduce the efficiency of other forces trying to divert the projectile from a strait course.
Ask anyone who has worked in missiles.

Edited by 24gerrard, 18 January 2012 - 22:55.

[Greg Locock]

Standard troll technique: make stupid claims, when asked to justify them claim higher authority or ignore it

[saudoso]

Mock away Greg if it makes you feel better.
The thrust from a jet or rocket will reduce the efficiency of other forces trying to divert the projectile from a strait course.
Ask anyone who has worked in missiles.

NOT

[Wolf]

If I may offer my slightly opinionated, biased, and perhaps unfounded opinion- it is that if one has to compare the layout as God intended it to be- front wheel steering and rear wheel drive, one loses some of the advantages either way the layout is changed... If one goes to rear wheel steering, when properly driven, the independent control of both ends of the car is lost, as both steering wheel and throttle steering are applied to the same set of wheels. FWD and RWS would make a horrible combo, if one was to try to reverse this effect- I'd say it would be something C. Smith would call an abomination- oversensitive steering (as if one was driving in reverse) and counterproductive throttle steering effect... And the only 'unnatural' option left is FWD and FWS and I say "bah, humbug!"- independent control of both ends of the car is lost, and (here I beg to differ with Gillespie) again throttle steering working against the driver.

[cheapracer]

FWD and RWS would make a horrible combo,

And I maintain that this is best for city commuting, everything car isn't about going fast.

"over sensitive steering" is a result of design (as mentioned in posts above), not a given.

[24gerrard]

NOT

Of course outside forces change the dynamics of a moving body that is a given.

However, if that body has a major force working in one direction, the outside forces later applied can only change that direction by a lesser degree
than if that force were not present.

[24gerrard]

And I maintain that this is best for city commuting, everything car isn't about going fast.

"over sensitive steering" is a result of design (as mentioned in posts above), not a given.

The sensitivity of rear single wheel steer in my idea would be negated by the application of electricaly controlled electric power to each front wheel motor. This gives a steering input to the front axle under fine electronic control from steering wheel input.
If the rear steering wheel excites an over sensitive turning reaction the inside front wheel motor is increased in its torque application relative to the outside motor.
The result is to make the overall steering highly controllable even to the extent of fully variable under to over steer capability.
With electronicaly controlled rear wheel lean
(sensor activated as in the project 425 LSR motorbike project I helped design which had gyro stability and hub center steering).
The lean can be set to occur in response to G forces thus achieving the required weight transfer needed to match or exceed four wheeled handling.

Edited by 24gerrard, 19 January 2012 - 10:13.

[Wolf]

And I maintain that this is best for city commuting, everything car isn't about going fast.

"over sensitive steering" is a result of design (as mentioned in posts above), not a given.

Blasphemy! (I checked your earlier post on the subject, and will think about your arguments, but still had to say it ;) )

In low speed situations, I'd call it a design trait- but on account of that RWS for city commuting would have a big selling point: parking would be a walk in the park, and might even be beneficial to reducing congestions in city traffic (one could just 'dive' in the parking place, rather than having to pass it and then parallel park into it, with the reswt of the traffic behind coming to a grinding halt). Some years ago the idea would be unpractical on account of mechanical linkage required, but with all that drive by wire, cars modulating throttle themselves, as well as applying brakes however and whenever they want- I would think that public fear of electronic (non-mechanical, to be more precise) solutions is gone and it would be quite easy to do nowdays (hehe, come to think of it, I could probably think of a big MFG or two that would put force feedback for more 'sporty feel').

[saudoso]

Of course outside forces change the dynamics of a moving body that is a given.

However, if that body has a major force working in one direction, the outside forces later applied can only change that direction by a lesser degree
than if that force were not present.

Each individual force will aways affect and object by the same amount. If your perception of one force's effect seems lesser due to more noticeable effects from other force applied at a right angle to the first the difference lies on the observer, not on the observed fact.

Edited by saudoso, 19 January 2012 - 13:04.

[Engineguy]

The sensitivity of rear single wheel steer in my idea would be negated by the application of electricaly controlled electric power to each front wheel motor. This gives a steering input to the front axle under fine electronic control from steering wheel input.
If the rear steering wheel excites an over sensitive turning reaction the inside front wheel motor is increased in its torque application relative to the outside motor.

Using two motors to "steer" fixed front wheels IS rear steer. For the unequal rotation of the front wheels to steer the vehicle to the right, the rear of the vehicle must move to the left, either by actively steering the rear wheel(s) to the left or by being free to comply like a caster wheel.
2-motor front axle... watch from 0:7:00 to 0:10:10

If you're boxed in with a parallel parking situation, you can only reverse out with rear steer... try to go forward your rear fender will smack the parking meter.

Edited by Engineguy, 19 January 2012 - 14:27.

[saudoso]

Using two motors to "steer" fixed front wheels IS rear steer. For the unequal rotation of the front wheels to steer the vehicle to the right, the rear of the vehicle must move to the left, either by actively steering the rear wheel(s) to the left or by being free to comply like a caster wheel.
2-motor front axle... watch from 0:7:00 to 0:10:10

If you're boxed in with a parallel parking situation, you can only reverse out with rear steer... try to go forward your rear fender will smack the parking meter.

That's exactly what youd like to have grandma driving, LOL.

[24gerrard]

Using two motors to "steer" fixed front wheels IS rear steer. For the unequal rotation of the front wheels to steer the vehicle to the right, the rear of the vehicle must move to the left, either by actively steering the rear wheel(s) to the left or by being free to comply like a caster wheel.
2-motor front axle... watch from 0:7:00 to 0:10:10

If you're boxed in with a parallel parking situation, you can only reverse out with rear steer... try to go forward your rear fender will smack the parking meter.

Only if used in that way.
The video does show how superior electric traction and control is.

[Greg Locock]

Of course outside forces change the dynamics of a moving body that is a given.

However, if that body has a major force working in one direction, the outside forces later applied can only change that direction by a lesser degree
than if that force were not present.

Your second sentence is either wrong or unhelpful in context. So you are either agreeing with me, or arguing that Newtonian physics is wrong in this instance. Your call, please check with your missile designing mates whether they want to chuck Newton out of the balloon. Do you know how to draw a free body diagram?

Edited by Greg Locock, 20 January 2012 - 02:46.

[Kelpiecross]

I thought the problem with high speed RWS was that to turn one way you have to first accelerate the rear of the car laterally in the opposite direction then accelerate it back in the direction you want to go, which would seem to me to be less efficient and stable than simply moving in only one direction. To change direction means having to out accelerate the lateral acceleration of the front of the car leading to a pendulum effect if not tightly controlled.

I thought this comment might be getting down to the basic reason RWS is not a good idea except on a forklift.
Front wheel steering moves the car initially in the direction you want to go - RWS moves the car initially in the opposite direction you want to go.

[24gerrard]

I thought this comment might be getting down to the basic reason RWS is not a good idea except on a forklift.
Front wheel steering moves the car initially in the direction you want to go - RWS moves the car initially in the opposite direction you want to go.

Good point but my idea is to use both rear and front steering in balance.

Edited by 24gerrard, 20 January 2012 - 11:35.

[24gerrard]

Your second sentence is either wrong or unhelpful in context. So you are either agreeing with me, or arguing that Newtonian physics is wrong in this instance. Your call, please check with your missile designing mates whether they want to chuck Newton out of the balloon. Do you know how to draw a free body diagram?

Poor old Newton, he has to put up with so much these days.
Cant remember anything about baloons.
I can draw all kinds of things although not as well as Tony.