Intro to Racecar Engineering: 11 King Pin Inclination
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- čas přidán 25. 07. 2024
- Smitty describes king pin inclination. This is the eleventh in the video series developed for UCI's racecar engineering program. (Smitty and the Professor series)
mechanicaldesign101.com/smitty...
I'm amazed how flawless you are when you explain those subjects, I could watch the videos for hours, best videos ever. This is gold and cannot be lost! Cheers for you and your team sir! All the best!
In the 1970's I had a VW Rabbit with what VW engineers called "negative roll steering radius". I'm pretty sure that meant that the kingpin inclination angle was steep enough so that there was a negative scrub radius and the centerline of the king pin intersected the ground outside of the center of the contact patch. The "negative roll" terminology meant that when the car was sitting still and you turn the steering wheel through it's range of motion from right turn to left turn, the right front tire would roll backward on the pavement a very slight amount. On every other car that I know of, the wheel would roll forward very slightly.
The way it affected driver experience was that I could point the car straight ahead while going down the interstate, take my hands off the wheel and the car would not wander to one side or the other. It did not matter if I was driving on one side of the crown of the road. It seemed I could go a half mile or more without touching the wheel.
This whole series is absolutely brilliant!
fantastic explanation I had a hard time understanding scrub radius and KIA but seeing it on a test rig really makes a difference. Thanks so much!
Your videos are sooo interesting and well-made!
Great video. love the explanations.
I am convinced that kingpin inclination and caster are utterly alien concepts to every single Red Bull Soapbox builder!
Sir, your classes are amazing! I'm waiting for a online course from you!
This is an amazing video just came across this series big fan now! Thank you. Translating to jeep in my head 😂
this vid should be nº 10 and the vid about caster is nº11.
Hi, I have a question. There is any scrub radius variation in a real working system? I think about how the contact patch could change during a corner, so i guess the SR will follow too. I this a problem? In some designs It could change from a positive to a negative one. Is this something we should think about during the design of the suspension? 404english
hello, how about the king pin angle in the heavy weight service vehicles, at what angle is for them the inclination desirable?
so if you use a king pin angle which is a bit more than the normal the first thing that you will notice during cornering,is that the car in the entry of a corner will be faster and probably sharper due to the force of the outside wheel to push and lift the front axle...so the less the scrub radius the more sharp the steering..correct???
Thank you very much professor
Damn, what a good explanation. Thank you
Got it, on a positive Caster angle, the wheel contact patch follows the the “Axis” of the steering pivot point.. and not the pivot point itself.
It's great vid, yet, I confused regarding he said that if decrease the scrub radius, on the vid 10:13, he explains that it'll put more of braking load to the steering axis ( king pin ), but on 11:00, he says the greater scrub radius will put more to the steering mechanism, which way would give more load to the steering axis?
Increasing king pin inclination and thus reducing the scrub radius will put more of the braking, pot hole, road friction and so on through the king pin. And if you decrease your king pin inclination and thus you increase the scrub radius, then the loads will go through the steering system more. Hope this helps.
Great explanation ! I have one question though about scrub radius.
Is it true and logical to expect for example that the braking forces or pothole - road irregularities, when scrub radius is negative ( outside of the tire centerline ) instead of positive ( inside of tire centerline ) are reversed, with positive scrub the wheel will want to toe out with braking force or rolling resistance, potholes. With negative though is it the reverse ( Toe in ) ?
Thanks.
Imagine the front wheel of a bicycle mounted, not between the front forks, but outside the forks to the right side.
While riding, if your front wheel would hit a bump, you would feel your handlebars jerk to the right and you would have a scrub radius of about 5". You could eliminate the problem with a zero scrub radius in two ways: The most obvious would be to put the front wheel back between the front forks. But another way would be to bend the front axle where it attaches to the right fork so that the wheel is now leaning to the right and the tire contact patch is back between the forks at ground level.
@@Bluuplanet That cleared it up for me a lot more and nice and clear example. Thanks for replying !
I’m modifying a 2005 dodge 2500 chassis suspension to narrow it for a 1948 panel truck body. I’ll be changing scrub radius and kingpin inclination. Would love to talk to you
What about changing theses angles by actuators in realtime ?
TY I just learned a bunch
6:19 i may be wrong but did u mean 79 80? Instead of 80 90
Very good explanation, i just wish the video wasn't in such a low resolution :(
thank you sir!!!
An explanation of the ramifications of neutral and negative scrub radius would have been useful.
Thanks!!
Thank you
The video is good and explains a lot, but the camera is too far away for the content to be fully understood. Cheers.
This should be compulsory watching for Red Bull Soapbox builders!
U think they would ZOOM in on the KINGPIN - but that would be too smart ?