On numerous occassions while watching “Knight Rider,” Kitt (driven by Michael Knight) would shadow a tractor-trailor on the highway, a ramp would extend from the trailor, and Kitt would drive up and into it.
My question: Is this indeed possible in real life?
Thoughts: Let’s just say that the 18-wheeler moves at 60 mph and the car you wish to drive up the ramp is moving at 61 mph. In relation to the ramp extending from the 18-wheeler, the car is approaching it at 1 mph. BUT… as soon as the car hits the ramp doesn’t it squeal up it at a now relative 61 mph, thus flinging itself through the front of the semi?
Conversely, a car backing down the ramp back onto the road from a semi would all of a sudden be instantly be moving relative to the road at 60 mph once the rear wheels transfer from the ramp onto the roadway–in essence going from -1 mph (backin down the ramp) to 60 mph in a matter of milli-seconds and destroying the drive-train in the process.
Not sure about getting onto the trailer, but as far as getting off:
Put the car in reverse, and back onto the ramps. Switch the car into Neutral, and let the car back off the ramps by itself (gravity, with application of the brakes to make it a slow backing), then switch into Drive (or the appropriate gear, but I don’t think Kitt was a stick-shift) and you’re moving at 60 mph with no damage. In theory.
Given that stunt drivers did the stunt for the scenes in question, I’d say it’s certainly possible to do the onto-the-ramp and the off-the-ramp. It may be damned tough, but then, Kitt was a super-intelligent car able to make up for David Hasselhoff’s crappy acting, so one can assign near God-like powers to it.
In a word, nope. You’re relative speed doesn’t change a bit merely because you come in contact with the 18 wheeler. You’re moving 61 MPH relative to the ground. The truck is moving 60 MPH relative to the ground. Assuming you hit the ramp smoothly, you will be doing 1 mph in relation to the ramp before, during, and after your initial contact. The big deal comes with whether or not power is still being transferred to the wheels once the drive wheels hits the ramp. Assuming its a front-wheel drive car, the most efficient way to do this would be to approach doing like 70 mph, then coast onto the truck in neutral, going into gear only after full contact was made. As long as you don’t attempt to transfer the same power to the wheels that was required to keep you moving at your old speed, you should do OK. In order to assure that, as long as you aren’t pushing on the gas WHILE making the transfer between surfaces, you should be OK.
Think about it this way. Imagine you are driving your car, and it hits an ice patch. If you are pressing on the gas when it makes the change of surface from ice to road, you will make a noticble squeel when you hit the road, since you had to apply MUCH less torque to the wheels to keep your car moving in the same direction at the same speed. If, however, you keep your foot off of the gas until after your drive wheels have hit dry pavement, you can make the transition without a noticble jerk in acceleration (assuming, of course, you discount the other problems with driving on ice).
Well the cars motion is still relative to the earth, And its momentum hasn’t changed, so once it is on the ramp it is not going 120 mph forward, it is still esentially going 60 mph forward. The tires on the otherhand would attempt to go 60 mph on the ramp, but I’d imagine the stunt guy would pretty quickly figure out how to drop off to not get too much of a jerk or squeal. The car was rear wheel drive, so you don’t have to think about the entire length of the car, just the foot or so between the rear tire being completely on the road, and totally on the ground. The front tire just turns on the bearings relative to how fast the ground is passing beneath it. In the Sci-Fi world of Knight Rider, I’d imagine KITT had enough control over his wheels to put put the front in neutral until they were on the ramp, then put the rear wheels in neutral and switch to front wheel drive at about 2 MPH, letting the rear wheels rotate freely. I havent watched in a while to see how clear the view of the operation is, but its possible that for the show they just drove the front wheel on the ramp into a moving track and put it in neutral, while it got winched up.
This thread puts me in mind of a terrific sci fi story called “The Roads Gotta Roll”. Help me here with the author’s name. At any rate, the rolling roads are akin to the moving sidewalks at airports, except that one moved inwards from the Way Stations, and in doing so, upon leaping from road to road, increased in speed. The inner roadway is moving at 60, you are doing 61. You are doing 1mph. Upon entering that roadway ( ramp to truck, in the case of this OP ), you are doing 1 Mph MORE than the ramp is, and so can proceed up it slowly.
The speeds are added when impacting, not when moving in the same direction. ( I know KNOW I’m gonna get my shit jumped here, because I audited Physics in High School, and failed the final anyway, but I know I am right in this explanation, I just can’t quote the right Laws here). If you are doing 25 Mph and the other poor feeb is doing 25 Mph, your Impact Speed is 50 Mph.
Not 20 minutes ago, I came back from the scene of a minor car accident. Both cars were doing at least 50, but moving in the same direction. A mirror side-swiped a car panel. No huge rending impact, no massive injuries. The net speed of the mirror striking the side panel was probably less than 10 Mph. ( The damage is because there was lateral movement as well, and so when the one person drifted into the other, there was damage, NOT from the fact that they were both doing 50+ Mph ).
P.S. As an amusing but potentially troublesome side note to the post above, the drivers were both okay. However, I did back my ambulance up into a LARGE sign that indicated “No U Turns Here”. Took it right down, it snapped BOTH vertical supports for the sign off about 6" from the grass level. <Sigh> They don’t call me Crash around the ambulance bay for nothing…
Cartooniverse
I’ve seen it in one or two other movies as well, so it’s definitely possible. Try to find an old film called The Italian Job, it’s a classic heist flick. The criminals make their escape in three Austin Minis (front wheel drive) and drive them into the back of a modified bus just as you described. No special effects required, just drivers who really knew what they were doing.
Actually, Heinlein’s used that in a couple of his novels.
Thank you for the replies. I would assume that the way the car gets up the ramp is to build up enough momentum so as to not be applying power to the rear wheels at the moment the wheels make contact with the ramp. So in essence the car coasts up the ramp.
Still, when going from semi back onto the road, those wheels are going to be going from a slight reverse roll to an immediate 60 MPH forward state upon hitting the road. Even with the car being in neutral there’s gotta be a problem with this. (and imagine if the front wheels are slightly off center when THEY hit the road–immediate loss of control!)
Lets assume rear wheel drive. KITT is moving at 61MPH and the truck (with the shapely mechanic :)) is moving 60MPH. KITT’s rear wheels are producing the forward motion of the car through contact with the road. The front wheels are merely along for the ride (much like Hasselhoff). As the front wheels come in contact with the ramp they most likely spin in place and eventually slow to traveling up the ramp at 1MPH. The rear wheels meanwhile are still applying forward movement on the road to keep going at 61MPH. When the rear wheels make contact, they will be applying a force on the ramp to keep the car moving at 61MPH. Using this site’s calculator, I get a stopping distance of 155ft. That’s a real long truck.
Yes, I believe it to be possible, but not at your proposed speeds. I propose that the car was moving more along the lines of 20-30MPH (26ft stopping distance) and the film was sped up or shot in way to look like they were going faster.
What I want to know is how KITT could get the exact layout of buildings and where people were in the building. Any WAG’s?
I believe you have a key point here. I’m not involved in the tv/movie industry, but I understand that virtually all stunts involving motor vehicles are done at fairly slow speeds.
Hell, I’ve always wondered how KITT could unlock handcuffs, engage another car’s brakes or freeze the back rotor of a helicopter all using a “microlock” signal.
You guys leave KITT alone !!! He used thermal imaging and gamma rays and a little bit of Magnetic Resonance Imaging to scan the buildings and people. After a quick scan he could tell the exact layout of the building, even secret rooms. Every person’s face has a distinct thermal image, so he was able to tell who was who.
The microlock button sent out an Electromagnetic Pulse that would disable cars and helicopters.
The handcuffs were opened with a high intensity microwave balsted at the frequency of the steel atoms in the cuffs. It was very localized and very quick, so it did not heat up the entire handcuff, it just melted the locking mechanism of the handcuffs. It could also break the chain in the middle. I never saw that episode so I dont know which option he chose.
They got such good live feeds because no one else was online back then taking up all the bandwith. Plus they have their own personal communication satelite, that helps a lot. KITT could also get Pay-Per-View for FREE.
The automatic tint KITT had was done with liquid crystals embedded between two layers of glass.
Bad guy tries to shoot Hasselhof at point-blank range, through Kitt’s driver side window. Unfortunately (for the bad guy) it’s bulletproof glass, so the bullet rebounds straight back, like a rubber ball, and hits the bad guy, killing him.
