[jerkitt]

Ok, this may be an old topic, but I figured I'd try to set some things straight.

This "hooper/reverse flip/whatever" can be done in any car with any tranny.... well... front wheel drive, anyways.

It works exactly the same as a car with RWD going forward, then cranking the wheel and flooring it. They spin.

Now, I've owned quite a few POS cars, including a white 1991 Cavalier Wagon, and rusty brown 85 buick skylark. Both were automatic. As well, I learned how to do what I called a reverse-180 on slick ice in the winter. Once I was confortable there, I took it to very rainy days. Then slightly wet roads... then gravel... and eventually to straight pavement.

Of course, a couple years doing that, and those cars are no longer with us. Not to mention their e-brakes, which were LONG dead... I will post a pick of what happened to the cavalier in my profile right away.

Anyways, once I got my excel, which was 5-speed, I started with that on ice. Worked like a charm. All in all, this can be done with any FWD car for sure.

Also, try cranking the wheel to either side, and just flooring it in reverse... reverse donuts, no? SAME as a RWD car going forwards.

One last thing... a friend of mine who had a 5-speed cavalier and a couple more years of driving under his belt....

Start forawards, gain decent speed
Pull e-brake for 180
throw into reverse while turning
reverse 180
throw back into "drive" while turning (whichever gear neccessary)
repeat process


The only reason he stopped was because he ran out of parking lot.... :??:
Being from Winnipeg, we have snow for practically six months of the year.... so everybody here thinks their a rally driver!

P.S.... my e-brake doesn't work anymore...:nervous:

 

[MechaniX_034]

Gonna look for snow one of these days.:evil:

 

[jerkitt]

definitely a must
and if you get an old POS car with a metal bumper, like my buick... then nothing will get in your way, and you can pull all this stuff whenever and wherever you want

IE. garbage cans, snowbanks, fences, curbs... and that old lady who ran into me on her bike... WHAT WAS UP WITH THAT?!

 

[MechaniX_034]

I was thinking somthing a little lighter, a little more compact and with lots better handling, but who knows bro, my bank account looks really weak right now so I may just have to go Pony. The engine may be weak but the rest of the car's a damn TANK.:rambo:

 

[jerkitt]

If you REALLY don't care about what car you get,
might I recommend a Pontiac Acadian (AKA Chevette)

Those things are BRICKS! My friend's had one in his family for over 2 decades, and he still has it. Rusty floor holes and all. I mean, the thing tops out at like 60 KM/H, but STILL! You could hit anything, and not a mark on the bumper!

I have no idea about Pony's. All I heard was that they were very unreliable, cheaply built, and had little to no safety features.

Anyways, let me know what you decide on

 

[MechaniX_034]

Don't faint when I do.:evil:

 

[jerkitt]

*COUGH COUGH* ... i DID drive a cavalier wagon.

There isn't much worse

check out the pic of it's death in my car's profile pictures

The wheel and hub ripped apart around a corner.... then i tried to turn into a side street, came to a grinding stop on the concrete.... then the wheel rolled into the side of the car... with enough momentum to create a substantially noticeable impact on the driver's door. It was funny! I laughed! :lol:

 

[MechaniX_034]

LMAO bro I'm laughing right now! How's you get the car outta there anyway?:lol:

 

[jerkitt]

had it towed.... they salvaged the axle... thank god... that would have been like... $1000... but that pics in my Excel profile now, in case you hadn't checked it out yet

 

[paltask14c]

Has anyone here taken ANY physics lessons? your car (and the tires, etc) are moving in a strait line: axis X. (reverse, say 25 mph) you put it in nuetral (or push in the clutch) the wheels are now FREE MOVING! you swing the car around (swap the tail for the nose) on axis Z(going though the center of your car, from the ground to the sky, like a pole). axis Y always stays the same (you hope). Your car goes 135 degrees around axis Z, so it is now facing practically forward. Your tires are ALSO no spining in a forward direction (the stop spinning forward around 90 degrees) after you cut your wheel straight again. your going about 20 mph, and slip easily into second gear. no tranny harm at all. i'll graph the maneuver if you wish.

During the direction change, you have the clutch disengaged from the engine, putting the car in neutral, and allowing the wheels to spin however they want, so they go from spinning "backwards" to spinning "forwards" with the direction of the car, so the tranny never actually "feels" this change, and never has to counter act it.

In an automatic, its a bit trickier. Its optimum that you swing it from revers, to N, then about 130-140 degrees, pop it down one more notch to D. It happens so fast, that your probably cant get the car into D before the direction change in the first place. but if you go straight from R to D before the tires change direction, the ol' slush box takes care of it all.

After you get this move down, go from D to R. Remember the book Christine...you never know when you're going to need that trick!

PS.
Christine is a book by stephen king, in it some "bad guys" are stuck in there car, speeding down a road, about to hit the wall at the end (or some other kinda dead end thing) so the guy does a 180 flip (from forward, to reverse) and "rear ends" the wall at like 100mph. Everyone in the back seat=:dead:

 

[MechaniX_034]

:evil::evil::evil:

OK here it is.

For the sake of common reference, we'll use the same points with point added for the third dimension(the one we forgot earlier) You describe Point Z as an axis through the centre of the car. However taking that the car has a 50/50 weight split front and rear, and has a 50/50 weight split across it's track(Axis E). Notice how Axis Z1 has come to an angle. This has been brought about by a shift in weight distribution from Point K1 to Point K2(A similar effect is had between Points L1 and L2, the rear wheels). This is dynamic weight transfer caused by the turning of the seering wheel, creating different coefficient of friction between the 4 wheels as weight is transferred between them and load is absorbed by the suspension, reducing load on Points(wheels)K1 and L1 and transferring more weight to point L2 and the majority of the vehicles mass onto Point K2. This is called crossloading. Basically this means that the wheels will not necessarily come to a stop at 90 degrees with the direction of travel at perhaps 92-97 degrees perpendicular to the tyre's slip angle(If no countersteer is applied) If countersteer is applied this angle is reduced to perhaps 37 degrees(assumed) at the front wheels with weight beind distributed unevenly between the front wheels. This means that the front tyres are closer to their optimm slip angle. You should know what that means; more grip on one wheel, less grip on the other because of counter-load on both front wheels being uneven. So the rear of the car slides /drifts a greater degree than the rear, with Point K2 being the point of cintact wit the most Coef. of friction, so this is t3h axis of the rotation(if drift corner is used). Axis E will experience cant towards the outside of the corner due to centrifugal force acting upon the mass of the car, and the suspension compensating for this, keeping all 4 wheels on the ground.

With this in mind, Axis X no lnger becomes the direction of travel, but the longitudal axis of the car's chassis. If you wish to denote the direction of travel, you would have to create another axis pararell to the contour of the roads. Take all these factors into consideration, with traction, crossloading and whatever the hell there is and you'll see that Axis X must be relative to unillustrated Axix R(for Road)that is paralell to the countour of the road. Because of t3h load on Point K2 as well as this point being the centre of rotation of the fixed points (K1,2,L1,2) the inner front wheel(Point K1) will slow or perhaps even rotate backwards if LSD is not equipped, all relative to the degree of rotation, slip anle and coef. of friction differential between Point K1,2 and Point L1,2. The same applies to the rear wheels.

The transmission(Differential) will begin to react to the change in the rate of rotation between the front wheels even before the car reaches 90 degrees perpendicular to the axis of motion of the inertial kenetic mass. So this point is moot, because the car's rate of rotation will require that 15 degrees be reached before 60 degrees and so on what knot. Same with the autobox. Changing geas quickly enough to make this move a success with an autobox will turn it's internals into mashed potatoes. With gravy. With crossloading going down between points K1,2 and different Coef. of friction going on between the tyres because of centrifugal forces acting upon Axis X and E, even with the clutch disconnected, the wheels may come to a NEAR-STOP but will still mantain a measure of rotation depending on road conditions, bringing the differential into play. Another cause of this is that your car is not only FWD, but the rotating inertial energy of the wheel's mass.

Notes:
-It is assumed that the vehicle has 50/50 weight distribution across Axis E and X, and Z, and that the absolute centre of gravity for this supposed vehicle is the intersection between Axis E,X and Z.

BTW dont pay atention to the pics, they're cartoons. Look a the axis instead and take the car for refferance only.

Uhhh I think there's more but I kinda forgot the rest. D'OH!!!:dead:

[Edited by MechaniX_034 on Oct 16, 2002 5:32 AM]

[Edited by MechaniX_034 on Oct 16, 2002 5:40 AM]

[Edited by MechaniX_034 on Oct 16, 2002 5:48 AM]

 

[jerkitt]

OH C'MON!!
You guys are sucking the fun out of driving! :dead:



why don't we just accept the fact that it works and it's fun to do? can we agree on that?
if I wanted to figure out the physics of it, I'd have done it on my own... but... you get the pointuzzled:

 

[paltask14c]

Dang, i thought that I got over technical with it! I left out the y axis, for simplicity sake. hopefully you werent going to flip the car! and yes, i assumed there was a 50/50 weight split, again for simplicity. I wasnt really going to graph it though....I'm going to have to dust of my old TI-81. Anyone want to factor in traction and wind resistance?:nervous:

 

[jerkitt]

OOH OOH !!
how about....
factor in a gravel road.... 12 feet across....steep ditches on either side..... on.... a windy day!

word to whomever decides to try this.... once your around in drive, don't floor it right away.... or at all.... especially if you over-rotated.....:dead:

not... that I... did that.... or anything....:hmmm:

 

[MechaniX_034]

LOL, you know they do make MathCAD for a good reason:lol:

 

[jerkitt]

it's for making squares in graphics class gre:

 

[MechaniX_034]

:evil:Naw dude the MathCAD's for us to make Hentai with!!!:evil:

 

[jerkitt]

Hentai eh?.... that japanese characters? or... chinese? or characters at all?


yeah.. and where's the "all your base are belong to us" from?
I know it from a song, but i'm sure the song dubbed it from somewhere else

 

[MechaniX_034]

Uhh bro Hentai is Manga or Anime Porn.:lol:

The "All your base" thing is a pic edit from another site, decided to change the image a little for a little misplaced "originality".X) The origin of the "All your base" thing is from a really bad video game called Zero-Wing.

 

[jerkitt]

well, had you said Manga or Animé or Japanimation I'd have known what you were talking aboot.

And I will check out that game tonight sometime :lol: thanks!