Landracing Forum
Bonneville Salt Flats Discussion => Bonneville General Chat => Topic started by: kustombrad on December 11, 2014, 12:24:14 PM
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I was in a conversation last night with a guy who's been running at El Mirage and Bonneville for the last 20 yrs. and I brought something to his attention. We were talking about spools and open diff's and getting HP to the ground. I asked him if he noticed that most cars making horsepower always (sometimes aero is weird) spin to the right. I told him my theory and he kinda chuckled because he never really thought about it. Before I ramble my thoughts I'm curious if anyone else has noticed this? Go to YouTube and check 'em out!
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And your theory is???? Inquiring minds need to know. :-D :-D
I have my own and want to see how your's compares.
Ron
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OK here we go... Landspeed racing is no different than drag racing, it's just a lot longer track. The idea is still to accelerate as quickly as possible with the traction available. If anyone has watched any drag race door cars (stock to pro stock) has seen the technology change on how they launch. In the old days the cars would pick up the left front AND the right rear with the brutal twisting motion of the engine vs. the ring and pinion. It went from a way stiffer right rear spring to an adjustable rear sway bar. Now with just a little right side preload on the sway bar, both tires plant (watch them launch now) on the ground evenly. On the flats everyone adds weight but never compensates for the rear suspension twisting. Under power the right side picks up ever so slightly and PLANTS the left...instant hard right! Now this is assuming the rear tires roll out is identical to rule out that possibility and it's a standard ring and pinion design. This is just my theory, but after seeing it happen over and over and climbing under the backs of numerous cars, this is the conclusion I've come to.
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Coriolis effect... they spin the other way in Australia... :roll:
The lakester has spun left and right... the liner went left. Jonny Hotnuts went left as well, maybe it is only roadsters that go right...
or not
:cheers:
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Did it go left or was that where the correction took it? A quick change is going to do just the opposite because power is coming from the back. Same if the engine is behind the rear end. My theory is with a bunch of horsepower involved. Sometimes stuff happens.
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Brad, I would think that a quick change would go the same way. It isn't the direction the pinion rotates, but the direction the driveshaft rotates. That's assuming that your theory has some credibility and I think it may. The reason for the twist is external and not what happens within the rear end. :? :? :x :-D
Pete
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.. On the flats everyone adds weight but never compensates for the rear suspension twisting....
I think that might not be totally true since I'm aware of some that have tried to pre-load the right rear.
You are never going to be able to get the hit on salt you can at the strip. Still when the throttle stuck wide open with me it went to the right and and the times I got in it experimenting it went to the right so maybe we should try more weight on that side,
Sumner
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The rear end is trying to get power to the ground from a 90 degree angle and since the engine turns clockwise from the front, it's also trying to pick up the right rear. A quick change is making a 180 degree power change so it would be the opposite. Same if the engine was mounted behind the rear.
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Kustombrad
I agree completely. Years ago Mickey Thompson wrote an article on leaving the line. On launch, if the car fishtails right, add weight or preload to the right side, or visa versa, until it launches straight. On the drag strip, if you watch the down the track cameras, if they get out of the groove, they pull hard in the the direction of the tire that looses traction.
At Bonneville, cross winds may have something to do with which way it spins.
Back in the 60's when I had a service station, I could tell whether a car had a posi by which tire was worn the most (young hot rodders) If posi, left tire was worn more because of torque loading and more weight on left when both are spinning.
IIRC Smokey even turned one of his Hudson's engines backwards to try to balance out the traction issues. Until he was caught.
Ron
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The mild preload is to compensate for the twisting motion. Look at some of the records that were set by solid mounted rear ends. On a smooth track they planted BOTH tires and were gone. My theory is with suspended cars. Instead of adding more weight Sumner, throw a sway bar back there to even (bring the left weight over to the right with an eighth to quarter turn) it out.
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When I posted my theory up, I wasn't trying to sound like a know-it-all, cuz I'm definitely not and still learning stuff EVERYDAY! It was more of me commenting on what I've observed and how I thought it would be a relative and easy fix. The sway bars are (in racing terms) inexpensive, can be installed with a minor amount of fab work and are infinitely adjustable! Will the car "plant" like a drag car? Not at all, but it will keep both tires "evenly" stuck on the ground without adding a bunch of unnessesary weight to the car!
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Brad, if I had access to large amounts of surplus cash I'd already be out in the shop setting up a quick change with an open rear end. I know that the front of the housing would still want to rise in reaction to tire grip and I still think the reaction of the housing will still be the same as a conventional rear end. I don't think what happens within the housing affects the reaction on the outside as long as the drive shaft and the drive axles rotate in the same direction. :-D :-D :-D
Pete
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After close to 30 years in the timing venue I have seen more spins then I can remember. But it many cases a spin is caused by over correction when the vehicle is drifting to the side of the courses and the driver tries to correct and doing so over corrects. This results in the spin.
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Glen, I'm sure you've seen more spins than anyone out there!
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Just out of curiosity Pete, why would you run an open diff?
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This subject should bring out lots of opinions, examples, beliefs, and maybe even some humor.... :-D
The subject of rear wheel drive type (locked, open, or limited slip) might have to do with the vehicle it's installed in.
Example: a roadster vs a streamliner. The roadsters wheels are much further apart than a streamliner. So if the roadster has a locked rear & runs through a spot of soft salt or dirt it MAY have a tendency to rotate around the tire that has lost some amount of traction. Where as the streamliner most likely will drive through this spot with both tires as they are much closer together. Now if the roadster has an open rear it may drive through this same soft spot and is less apt to try and rotate as the wheels are not locked together.
But after years of watching different race cars on the salt & dirt one thing I do know, I don't know why some cars spin more than others. But I am inclined to agree with Glen, drive input has something to do with it. Ask guys who spin at El Mirage & you'll get "I hung with it to long" or "it happened before I knew it" type answers a lot of the time.
Carry on...
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The stiffer the sway bar (and the frame) the less preload needed; a good thing, since the car needs to go straight with a range of torque inputs. They sell VERY stiff sway bars for drag cars.
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Just out of curiosity Pete, why would you run an open diff?
Just to see for sure which wheel would have traction and which wheel would spin. I think I know. I think the result would be the same whether it's a quick change or a conventional rear end. An open rear end would just emphasize the result.
Pete
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I agree with Pete. If you consider the tires,axles,gears are all resistance to turning by the driveshaft. As the driveshaft is trying to turn against this resistance, regardless of all the gears, and which way they turn, it is loading the left wheel (rear wheel drive non IRS)
The rear end in my roadster is mounted solid, but i can see torque lightening the right side to cause issues. It has spun several times before I got it and I intend to add weight to the right side.
of course YMMV
Ron
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A short pitman arm is cheap insurance.
(And no, that doesn't count when you break traction at 180 with a 35 MPH crosswind.)
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This all applies to a live rear axle. If a rear differential is driven through a torque tube, the engine torque does not cause weight shifting from one wheel to the other since the engine and differential are connected solidly together by the torque tube. Ditto for a car running a transaxle.
These effects may or may not overshadow the open/locked rear end question.
Regards, Neil Tucson, AZ
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I do know the 180 degree power turn does the exact opposite with the nose of the quick change. It actually shoves the nose down. This I know from a friend who put one in a sand dragster to keep it from doing wheelies the full 100 yds. Yes, it worked drastically!
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I certainly agree with comments by Stan and Glen. I had one spin that was caused by a crosswind just past the "2" at about 170 MPH pushing the Roadster to the left. A very small correction resulted in a very interesting circular sight seeing tour.
Slowed down the steering and never had a problem again. ( Too much horsepower and wheelspin was never my problem.)
Tom
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Brad, 2 PMs sent.
Pete
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Got 'em Pete! ;)
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And we haven't even gotten to the Detroit Tru-Trac [Gleason-Torsen] gear type differentials yet. Essentially an open differential transferring torque to the wheel with less traction to keep things going straight.
This is making my head spin. I think I'll have another beer. :-P
Doug :cheers: :cheers: :cheers:
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Sent you one more Brad. I'll now sit back and observe for a while. :roll: :roll: :-D
Pete
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One of the interesting things to ponder is the effect of actual torque inputs against the salt, at speed. Most of us who've run a roadster out there have experienced the sideways slips that are hard enough to bang your helmet in the cage.
I was thinking about tire slip angles, when that happens, and how far the car is traveling per combustion event. A V8 running 7200 rpm at 200 mph, straight thru high gear and 3:1 axle with 28" tires....is traveling more than 7" per combustion event. Thats over 2 feet per crankshaft revolution.
Our 4 cyl roadster was running about 5700 rpm at 175 on 28" tires....anyway, its over 2.6 feet over the ground per crankshaft revolution. It never quite got away, but there were a few thrills.
I dont think anyone has much luck catching the car once the slip angle gets very far while power is on. Those widely spaced power inputs are more like a skip than a slide, and a spin would sure be easy. You can travel alot of distance on not that many crankshaft rotations. Especially with a heavy flywheel, which wont prevent tire slip when the tires are out of line with direction of travel.
The other interesting thing is how far the tires slip during each power event. In 2004 I was measuring the blister spacing and length on the Buckeye Bullet after a near 300 mph run. Doing the math from motor rpm (3-phase electric), I found the blisters were exactly the spacing of armature torque inputs for the gearing they used. Those blisters were pretty short, maybe about 3" long. My best guess (just guessing) is that they were transitioning to square wave 3-phase at some higher motor rpm. We did the same thing on the Prius that year, at about 93 mph. Torque takes a jump for a while, with that method, but it makes for pretty hard, short hits.
Really odd to consider, isnt it? Of course....Probably doesnt mean a thing, but it makes you wonder if its part of the mix.
P.S. Edit..... I was thinking about that getting banged around, and it only happened in cross winds. The worst ride I remember was a return run when they came down the line giving everyone the option of waiting a while if they didnt trust the wind. The thing I remember was that it didnt feel so much like a slide, as some banging back and forth. Anyone else had that?
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JimL;
Not to be too nit-picky but tire "slip angle" is a term used to describe the difference in the angle between the tire contact patch and the angle of the wheel. In other words- how much the tire is twisted between the wheel and the pavement when going around a corner at high speed.
I think you meant something other than this-- "torque angle" maybe? (my made- up word :-) )
Regards, Neil Tucson, AZ
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Yes, that sounds better.
I would think we'd also have actual slip angle with these tall, thin, sidewalls. Thinking about my bike, which is a V-twin, it also tends to jerk a bit in side winds if I try to stay on the throttle. I dont think I could have slip angle problems with these BT003 Race. They are sure stiff.
Like I said, maybe means nothing....I dont really know. :|
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Ask guys who spin at El Mirage & you'll get "I hung with it to long" or "it happened before I knew it" type answers a lot of the time.
I had both of the above happen to me while driving Skip's roadster this year. We could write a book about the changes we made over the year but my first spin (in competition) was largely a "front end" spin and I drove the car too aggressively and knew the spin was coming. The spin was slow and fairly controlled. We made a major change after that by locking out the rear suspension making the car solid in the rear. The next month the car went straighter than it ever had until it snapped left and spun. This second spin was a "rear spin" in that the rear tires broke loose (could see rpm spike in data log) and the back end of the car came around pretty quickly.
IMO there are too many differences between cars to come up with a valid theory as to why cars appear to spin a certain direction most frequently.
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... I do know the 180 degree power turn does the exact opposite with the nose of the quick change. It actually shoves the nose down...
I can't agree with that; as long the resulting torque on the axle(s) is in the forward direction, the resisting force (on the housing) will be to the rear.
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After close to 30 years in the timing venue I have seen more spins then I can remember. But it many cases a spin is caused by over correction when the vehicle is drifting to the side of the courses and the driver tries to correct and doing so over corrects. This results in the spin.
There's your answer. :cheers:
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"for every action, there will be an equal and opposite reaction" If force at the front of the tire is moving down (forward direction), the force at the front of the housing (pinion) has to be up.
No dog in the fight but I did stay at a Holiday Inn Express :-D :-D :-D
Ron
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I was telling Pete about the quick change in my friends sand dragster and how the car stopped carrying the front end after the install and almost plowed the 100 yds.. I could be and probably am completely wrong on that one. Yes, spins can happen no matter what just because of the tire spin, all I was commenting on was how many go right because of the right tire being unloaded by engine torque. I'd still do the sway bar deal, tighten it to take the slack out of the bolts and fine tune it from there. The solid cars will continue to haul butt but it has to be a smooth surface as any bumps will unload the chassis and cause instant tire spin. It's pretty cool seeing all the comments and different ideas on here and I love being part of this group! Hope to meet more of you this next summer! Brad
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... The solid cars will continue to haul butt but it has to be a smooth surface as any bumps will unload the chassis and cause instant tire spin. It's pretty cool seeing all the comments and different ideas on here and I love being part of this group! Hope to meet more of you this next summer! Brad
Take a look at Sparky's old lakester and it accelerating with a solid rear (runs a torsen though)....
https://www.youtube.com/watch?v=PtGmGTHK6qc&list=UUxFiJQoy2NEbltvkvT2q71g (https://www.youtube.com/watch?v=PtGmGTHK6qc&list=UUxFiJQoy2NEbltvkvT2q71g)
.... try not to do this....
https://www.youtube.com/watch?v=fPnvgj1Bdgk&list=UUxFiJQoy2NEbltvkvT2q71g (https://www.youtube.com/watch?v=fPnvgj1Bdgk&list=UUxFiJQoy2NEbltvkvT2q71g)
..... The car later ran over 300 and got him in the 300 mph club :-). We've never been able to accelerate like that with the Stude and it is sprung and has almost twice the weight and about the same HP. With a 1.93 first and a 2.47 rear never more than 50% throttle in 1st and about the same in 2nd.
Sumner
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The 222 Camaro runs a locked rear end and suspension and has run 280 mph at the 21/4 and 294 in the 1st mile
when it blew just before the end of 1st mile.
Have to ease into throttle as wheel spin will cause a spin and the rear comes around to right.
Adding new spill plates and spoiler flap should help acceleration and spin recovery.
If you watch our videos in build diaries you can see Troy saving a spin a couple of times at El Mirage. I believe its because of his faster reflexes [ I always spin ] :roll: You can see Troy moving the wheel back and forth quite a bit.
Anyhow I wonder if faster steering would help me catch the spin faster. Check out sprint cars, just reading that they have a 6-1 ratio. Not that fast for Bville but faster than what we have.
JL222
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Just to through some thought on what Stainless said about his lakester and streamliner.
Stainless said "The lakester has spun left and right... the liner went left." Remember that in his lakester the engine is mounted cross ways to the chassis so engine torque has no effect on drive wheel loading and in his streamliner the engine is (was) behind the rear axle and unless it had a reverse running engine engine torque would unload the right wheel therefore spinning left!
Rex
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If it unloaded the right, it would plant the left and go right.
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Brad, you are right! I stand corrected, as I said on their liner with the engine behind the axle the torque load would be opposite a normal engine so the spin, if caused by engine torque, would be to the left.
Rex
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My initial comment was cars spinning to the right because of the right side tire unloading under engine torque. Tires spinning can make it spin any direction, but my comment was the right rear unloading under torque just enough the push the left down and make the car go right. It happens way more than to the left if you look for spin videos on YouTube.
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To prove my point in the simplest way I know how, here's some in car video of the most famous car out there. This is what happens when the rear end twists and loads the left tire. Watch how during the pass and the motor is making power, he has to compensate and drive the car to the left. If both tires were planted evenly, this wouldn't happen to just one side. Then notice how the steering wheel goes dead straight as soon as he shuts it off. If it was wind blowing from the left, he'd still be turning to the left. On the last video, look how much input to the left that is happening right before the crash.
Replay XD1080 The Fastest Camera on Earth: Speed …: http://youtu.be/B7tf6nGA1U4
2013 Speed Demon Run: http://youtu.be/T8oyW61fLCI
Crash dans le désert à près de 600 km/h (POV): http://youtu.be/oKpQDWtZkFo
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look at link below and comment... I'm 3rd up in the red roadster...nose went down in a soft spot, butt started to swing around, yep, I over-corrected and pulled the chute and a couple of buttons out of the seat padding.
http://www.landspeedracingvideo.com/videos/spins.wmv
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Wow! That was some crazy, seat puckering videos! I was never saying they all spin to the right (but since we're watching that video, how many went right?), I'm saying that particular issue can be fixed easily enough, so you can get farther at speed until your NEXT set of issues arises! If BOTH tires are planted EVENLY and spin, it's a crap shoot on which way it'll go. I still look at this as a really long drag strip and always will. Obviously, you can't launch the same way, but the car twisting and unloading the rear tires on a dragstrip at half track is very much relevant in THIS sport! The drag guys got tired of fighting it and have numerous fixes for that problem without adding weight. Adding lead to one side or another is just a band aid for the actual problem ( you'd need to change the spring rate AND revalve the shock for the weight difference on how the suspension reacts), plus the added weight slows the acceleration of the car. Fix the problem first with something as simple as an airbag and add weight when the car hits it's wall/air barrier and unloads the rear end (i.e. spun the tires at 170mph, added 200lbs and went to 190mph before they spun again) and go to the next thing.
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Brad, I really like your idea of adding a little wedge to the chassis to even the tire traction loading. We use it all the time in oval cars to do the same thing but didn't think of using it for a straight line vehicle. Sometimes you have to look a little closer to see the obvious. :roll: :roll: :roll:
Pete
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That AND rear tire roll out Pete! In roundy stuff that's also a huge part of car stagger. I've seen LOTS of guys checking air pressure but never roll out/tire circumference to see if they're the same size. If they (tires) say 80 lbs air pressure jack it up, put them at 75 lbs and measure the circumference of the tire. If ones a 1/2" shorter add air until they are the same, then fine tune it. When you're in line waiting, keep the sun OFF your tires because the heat expands the air and will make the tire bigger. This racing is like any other... It's all about the DETAILS!
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Brad, I really like your idea of adding a little wedge to the chassis to even the tire traction loading.
I'd think the more anti-roll you have, the less wedge you need, and the more consistent the handling with varying levels of force applied during the run. You also need a torsionally stiff chassis, but LSR chassis are a pretty stiff as a side effect of being crashworthy.
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Brad is so right on the roll out, we had 4 new MT tires last year 2 were different
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My deal isn't really wedge, it's like Tortoise said and more about anti roll and even weight on the back tires at all times.
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I don't want to get into a pi$$ing contest but I will add this. The anti roll bar is simply another spring and if you add preload through an anti roll bar you are jacking weight using a different tool.
I probably screwed up by A$$-u-me ing that everyone would be checking roll out to ensure it was equal. I've always bought tires in pairs and then in the good old days with bias ply tires if one was slightly small we'd over pressure the small tire and put it out in the sun to stretch it.
This is a really interesting debate with a lot of variables.
Pete
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I don't want to get into a pi$$ing contest but I will add this. The anti roll bar is simply another spring and if you add preload through an anti roll bar you are jacking weight using a different tool.
Agreed, but with stronger anti-roll, you need less pre-load, as measured statically on a scale.
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It's all good Pete! As far as being another "spring", that's kind of a yes/no thing. Tortoise said it perfectly. We're not talking about a little 1/2" twister like the old days. We're talking about a beefy bar with little to no (unless you have 4000hp) twist that's basically making your rear think it's on a swingarm, if that makes sense. As soon as the torque starts twisting and raising the right side, it's essentially raising the left the same amount and keeping both tires evenly on the ground. If it still twisted a bit all it takes is literally an 1/8" turn to even it out. This is very simple technology (and relatively inexpensive) that works. I'm not sure why the land racing community is afraid of stepping out and trying stuff that actually works. Just because we're "grass roots" doesn't mean we have to be behind the times!
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And for guys with leaf springs, "Caltrac" bars made by Calvert Racing are really awesome!
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And for guys with leaf springs, "Caltrac" bars made by Calvert Racing are really awesome!
I've had them on my pickup for about 15 years but they haven't done anything to stop the salt damage :evil:,
Sumner
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Hmmmmm... I'm really not sure what to say. I did some more homework on Speed Demon because the twist thing was bugging me on THAT particular car. Sure enough, they did it right on the back of that car and DID put a swaybar on it. I guess crazy amounts of horsepower will twist just about anything! I'd still like to ask George why it pulled so hard to the right though.
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This is Lionel West in Australia, spinning left
https://www.youtube.com/watch?v=jz74cgTYvlo
This is the in car
And if you look real close at about 1:39 you can see our new timing equipment
https://www.youtube.com/watch?v=kno02BFLxd0
So based on the evidence of one video........ :evil:
G
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Yep, it spun left! :-D
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KustomBrad,
Personally I think you have a very valid point with your observations. But using the Speed Demon runs
and specially the one where it crashed, is not really a good example.
Check out this video, called "Something Evil This Way Comes"
https://www.youtube.com/watch?v=XoriCmQD5zY
Look at about 12.25 and watch the rear camera.
Look at about 15.15 and watch the rear camera.
Then watch the video you had posted before.
http://youtu.be/oKpQDWtZkFo
Notice a difference in the runs?
Look at the following pictures from George's last run. (from Mike Cook's Shoot Out Page)
(http://i1212.photobucket.com/albums/cc453/vintageflth/Speed_Demon_Tracks_1_zps4e24d110.jpg?1419401787841&1419401789404)
(http://i1212.photobucket.com/albums/cc453/vintageflth/Speed_Demon_Tracks_2_zps1470057c.jpg?1419401787841&1419401789404)
Look at the last picture and zoom in real close on the tires.
(http://i1212.photobucket.com/albums/cc453/vintageflth/Speed_Demon_Tires_Gone_zps17133484.jpg?1419401787840&1419401789403)
What do you think? I think the Traction Control was just not set up correct on his last run.
In the video "Something Evil This Way Comes" George says "It's so easy to drive this car at 429 Mph",
well it was not on this run.
Really enjoy this Thread. Let's hope we all learn from every bodies feedback.
Mike
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.....What do you think? I think the Traction Control was just not set up correct on his last run. ....
In George's interview in BRN he said when the car is up to that speed (high 300's) he is the traction control (surprised me) and he said that it was a combination of more HP than previous runs, slick spot on the track and him being too aggressive with the throttle.
Again you guys are missing a lot of good info by not subscribing to Bonneville Racing News. It is the best thing out there for land speed racing. This site is great and also invaluable but you won't find the information here that the in depth articles and interviews there will give you. They can really help you regardless of if you are a car or bike person. Subscribe now and also order reprints of a number of the past interviews that are available and have info you would probably never get even talking to the bike or car owner,
Sumner
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I received a great email from Tom Burkland about Speed Demon. My using that car as an example was both right and wrong. I still stick to my theory and observations of torque twist loading one tire but it's not really a fair analogy of George's car. Tom reminded me that it's essentially a long, narrow "tricycle" with no front axle. Without a "standard" front end to use as leverage the car will always be twisting regardless of anything being done. Was George driving left to keep it from going right? Absolutely! But by the design of the car there's nothing that could be done to change that apart from mounting the engine sideways and having the engine torque go front to back instead of side to side. When I started this thread it wasn't to point at or pick on one particular person, it was to comment on why I see lots of cars spin one particular way. If a car is planting both tires "evenly" and you're being easy on the gas, it won't blow the tires off (and potentially spin) until it hits its air "wall" and unloads the tires. Only then should you be adding either physical or air (down force) weight. LOTS of people forget this is racing and (or maybe it's just me) you want to ALWAYS be out thinking your competition. Using a peg-leg rear end or adding a bunch of weight "just because" is just some band aids for the actual issues. Fix the "actual" issues and seriously go after some records!
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And looking at the picture of George's car on it's side again shows what I'm talking about. Which tire is destroyed from all the pressure and spinning on the salt?
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Fix the "actual" issues . . .
The Speed Demon cockpit canopy extends much further forward than needed. Low drag, no doubt, but moves the CP forward a bunch.
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Tortoise, the canopy, windshield, CP, CG, etc. is not the point here and had nothing to do with it spinning. None of those caused the car to go right every time he rolled hard into the throttle and the picture of the car on its side and the left tire showing cords validates what I've said. Piles of horsepower, the car's twisting motion, loose salt and George "getting with it" were the causes of that deal. That car by design still had LOTS of records left in it!
My comment of "actual issues" was not referring to Speed Demon. George is one of my heroes in the hot rod "world" and I'm sure he'll be back to kick more butt!
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Tortoise, the canopy, windshield, CP, CG, etc. is not the point here and had nothing to do with it spinning.
As George said in the interview in BRN (more or less) the car was stable for many runs before conditions finally were too much and it went around. He notes that the cars CG was behind the CP and also notes that it won't be if there is a new car
Neither you nor I know whether aero forces could have stopped the spin.
George is one of my heroes in the hot rod "world" and I'm sure he'll be back to kick more butt!
Agreed!
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Yep, it spun left! :-D
That's left? rear end swings to right and is to drivers right. Guess its like making a left turn.
Anyhow that's how the 222 Camaro spins, rear end slides to right. But its left?
Now its almost Turkey time :-D
JL222 :cheers:
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And to end all this, refer to Newtons third law of physics " For every action there is an equal and opposite reaction"
. Meaning that the pinion has EXACTLY the opposite torque in relation to the ground that the engine has. Watch a nitro F/C leave the starting line, Both front wheels in the air and going straight. SAME amount of traction on each tire,maybe some chassis flex but same weight.
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If the chassis is torsionally stiff behind the engine, no rear suspension or rear suspension with very strong anti-roll, engine torque won't cause much unequal wheel loading, especially with the front wheels inline or in the air. Rapid engine acceleration, like when traction is suddenly lost, will twist the whole car. You can see the result of this force when winging the engine while out of gear.
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If the chassis is torsionally stiff behind the engine, no rear suspension or rear suspension with very strong anti-roll, engine torque won't cause much unequal wheel loading, especially with the front wheels inline or in the air. Rapid engine acceleration, like when traction is suddenly lost, will twist the whole car. You can see the result of this force when winging the engine while out of gear.
:cheers: Yup!
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So if you put the engine and transmission in facing east west ?
G
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So if you put the engine and transmission in facing east west ?
G
You'll probably increase frontal area and require some expensive custom unproven driveline bits, unless it's motorcycle powered.
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Tort... Bonneville runs on unproven bits of all types... innovation is encouraged... :cheers:
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Tort... Bonneville runs on unproven bits of all types... innovation is encouraged... :cheers:
Innovation within the rules that is
G
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Hold a spinning die grinder with a cut off wheel as if it's the rear in a land speed car . If the "rear" yaws in either direction the outside "tire" dips . This says at the start of a spin the outside rear tire suddenly gets more traction guaranteeing a spin . Could spins be that simple ? Could spins start with unequal traction , gyro loading makes it worse till CP/CG takes over .
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Make sure it's an angle grinder to use that theory. Does it twist either way equally when you flip the switch (leave it on and just plug/unplug it) or just twist one direction? When you turn it on, that's the ring and pinion torque load (twist) I was referring to with it unloading one and loading the other side. If you really want to make it like a landspeed deal, hook it to a rheostat and "hit" it. Level it off at part throttle and "hit" it hard again. Is it twisting when you "hit" it or just staying even?
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Brad you may be missing what I'm talking about . It's not the acceleration of the car or die grinder , it's when the car yaws that gyroscopic force tries to roll the car in the direction of the yaw . A cut off wheel in the die grinder adds a lot to the gyroscopic effect making it more obvious . Point the axis of the spinning die grinder north . As you change the aim to NW or NE it tries to pitch up or down . Same for an angle grinder but with the 2 axis the effect is less clear .
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Here's some food for thought from over 50 years ago: The original plan for the Gyronaut motorcycle was to have it equipped with two contra-rotating gyroscopes to keep it going in the intended direction. During WWII, Alex Tremulis had pulled apart the gyros in the German V2 rockets and immediately thought that if the gyros could be programmed to land in the center of London from Germany, then why the hell couldn't they be programmed to keep a car on the racetrack to eliminate spinouts. He was on a mission, especially following the 1964 deaths of Eddie Sachs and Dave MacDonald. The Gyronaut was to prove his concepts, but he couldn't get sponsors, Lear or Sperry, to jump on board. As deadlines neared, the plan had to eliminate the gyros, and switch from the Ford V8 to Bob Leppan and Jim Bruflodt's twin Triumph 650cc setup, calling it the X-1. The X-2 was to have the V8 and gyros and the X-3 the jets to go supersonic. Alas, only the X-1 was built. Still, pretty advanced thinking outside the box...
(http://i652.photobucket.com/albums/uu248/gyronaut/gyronautscopes_zps8a0a8f2a.jpg)
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I do understand what you're saying and I wasn't trying to get too far off track. What is causing the "yaw?" Is it the rear suspension twisting? Are both rear tires the exact same circumference? Did it hit a soft spot? Did it hit that air "wall" where it can't go unless static or air weight is added? Too heavy of a foot? Too soft suspension? Lift? Once you narrow down the variables it'll be obvious.
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Brad you are talking about driveshaft torque starting a yaw . I'm talking about gyroscopic effect turning a slight yaw into a spin .
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At one point in this video of 2 spinning gyroscopes on a beam it shows how yaw causes roll . This is why a motorcycle naturally leans when when it turns . It also shows how with a car going down the salt a little yaw loads the outside drive wheel turning a slight yaw into a spin .
http://youtu.be/vGun5athdfg
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:cheers:
Thank you!
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Interesting, and a really neat machining project for when I run out of things to do. :roll: :roll: :-D
Pete
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At one point in this video of 2 spinning gyroscopes on a beam it shows how yaw causes roll . This is why a motorcycle naturally leans when when it turns . It also shows how with a car going down the salt a little yaw loads the outside drive wheel turning a slight yaw into a spin .
http://youtu.be/vGun5athdfg
To bad half the steps were left out when gyros were spinning in opposite directions :roll:
JL222