flattrack technique

[MikeT]

Originally posted by Ace McCool
I still disagree.
The centrifugal force, which is felt,

Correct

Originally posted by Ace McCool
is not the rock moving outward but the tension on the string is from the force you need to apply to pull the rock inward; to keep it from shooting off.

Not really, the rock is moving outward in a big way. What Jaybird means (correct me if I'm wrong) when he says "plot it out, is to draw what's called a free body diagram of all the bodies in the experiment. When that diagram is plotted or drawn out, you can see all the forces acting on everything in the system. Lets take the rock and string example. In this example there are three pieces with many different forces, the rock, the string, and your hand. We, for simplicity because this is already getting too complicated, will eliminate the hand. The string (when spinning) has a forward vector (force) moving it around in a circle. It also has the force of its own mass pulling it, or pushing it outward (just as Jaybird pointed out, the car door is also pushing out) on the rock. The rock has the force of its own mass wanting it to continue in a straight line because of the centrepital force but it keeps going in a circle because of the string. As long as the maximum tensile force of the string is not exceeded by the centripetal force of the rock plus the mass of the string, then the whole system is in eqlibrium until your arm gets tired. Side note, in this example there is also the gravitational force acting on all involved, I didn't want to add more to the mix.

Originally posted by Ace McCool
Centrifugal force in this case as well as with the car is just the felt force of centripetal force.

Aren't we saying the same thing here? Can't we all just get along.

Really, I think if you took my little story above and replaced the rock with your body on the flat track bike, the string with (more or less) traction (less because traction doesn't have any mass) and the spinning force also with traction, you'll have some good lap times! :D

MikeT

 

[Saratoga]

OL'89'ER: Your explanation was very clear to me. I wish someone would have explained it this way to me about 25 years ago. What does your call sign mean anyway?

 

[High Lord Gomer]

Rumor has it that, back when he joined DRN, he was a spry 89 year old. Now he is merely a 90-something year old fart, but doesn't want to rejoin under a new screen name because he has forgotten his email (and street) address and wouldn't be able to make it back on. :p

Seriously though, Terry, please don't let the fact that the geek sqad (sic) (:)) went off on discussing insect attractions (centipedal forces?) keep you from sharing your info with us. I figure I'll listen to anything someone has to say if I know they've been full-throttle and full-lock in high gear on any motorcycle.

(I got nervous just typing that. I think the only time I was full throttle and full lock on any bike was at 3 mph in a slippery turn just before I went down.)

 

[Ol'89r]

Originally posted by High Lord Gomer
Rumor has it that, back when he joined DRN, he was a spry 89 year old. Now he is merely a 90-something year old fart, but doesn't want to rejoin under a new screen name because he has forgotten his email (and street) address and wouldn't be able to make it back on. :p

BWWWWWWHAHAHAHAHAHA!:) Good one Gomer, glad to see you are fully recovered and back to your old self.;)

No worries, I don't let things like the geek s**** bother me. Kawi has a hard time figuring out how to get around any corner that doesn't have a berm to bounce off of.

Saratoga. My call sign is my AMA racing number, 89r. When I try to sign on at DRN and can't remember my name, I just go out to the shop and look at my number plate. Works every time.:confused:

 

[MikeT]

Originally posted by High Lord Gomer
Seriously though, Terry, please don't let the fact that the geek sqad (sic) (:)) went off on discussing insect attractions (centipedal forces?) keep you from sharing your info with us.

Hey! Who you callin' a geek? I don't even know how many legs a centipede has anyway..:confused:

 

[High Lord Gomer]

Originally posted by a Geek Sqad member
[Hey! Who you callin' a geek?

Actually, I was more referring to young novice riders attempting to correct an expert old man. but if the pocket protector fits... :scream:

 

[longtime]

Mike's a good guy. Gomer's right 'bout 89r, though. We best respect our elders. Specially ones that can still light it up. Got some video of a recent hill climb spree with 25 DRN'ers. Guess how many could even touch his rear fender? None. Better yet -- ride the fire roads with him. That cracks me (and others) up every time. The old timer can't -- and I mean CANNOT -- keep either wheel from sliding on any turn. Controlled slides, on every turn, both wheels, in complete control, always pinned, often 5th gear, never by use of brakes. It's fun to watch people try to learn from this/emulate it. Cause some can . . . for a while. But if you do this, and the slightest things goes wrong. . . yikes! :scream: Course I remember the last major bar-banger, where a sponsored desert racer was really pushing it, and Terry was too, and he hit a huge rock while 5th pinned two wheels slidin' -- that was a sight to behold -- and one that someone who might have been following his technique up to that point would have been toast.

Oh well, if it makes any of us lesser-skilled, mortal riders feel better, Terry may well be off on the physics of it all. He may not know the Newtonian reasons behind why what he does works so well. This is a clear cut case, though, of where science must take a back seat to art. Poetry in motion is more importantly created than explained, methinks. (This from a scientist, btw.).

 

[Boozer]

LongTime, thanks for your last post. that made me smile while reading it! this is a good example of how things in theory (the mechanics behind it) hold little value when time comes for the practice. everyone here can post all they like about the 'physics' behind the perfect slide, but at the end of the day, i want to hear what Ol'89r has to say.
There is this one friend i have the oppertunity to ride with, and he too was a former dirt track rider. There is nothing better than watching him slide both wheels through corners, again in complete control. LongTime, i know the feeling. He cracks me up also!
Ol'89r, don't take this wrong way, but would you consider being my foster grandfather? we can crack out the bikes on weekends while other grandfathers are out sailing boats or throwing lawn bowls!

 

[Ol'89r]

Awww shucks, you guys. Your making me blush like MXBetsy.:o

LT. The credit goes to the awsome power and tractability of the modern day four stroke. I just sit there and twist that little twisty thingie on the right side handlebar and the thing goes up anything I point it at. I'm just a passenger.

Boozer. Aye mate. You will have to take that up with my real grandson.;)

Ol'89r

 

[Rich Rohrich]

Terry here's a picture with Rich King and Nicky Hayden in what appears to be the stages of the technique you described. Nicky's throttle looks to be fairly closed while Rich has it open and driving. Can you explain the specifics of what each of these guys are doing? Thanks.

 

[MikeT]

Originally posted by High Lord Gomer
Actually, I was more referring to young novice riders attempting to correct an expert old man. but if the pocket protector fits... :scream:

You are a funny guy! I will meet you soon.

MikeT

 

[High Lord Gomer]

So how hard did Rich slap Nicky after he took him out by sliding the 450 up under him? :scream:

MikeT...I'm hoping to see a ride report when I get over to the Genral forum... :D

 

[Rich Rohrich]

Originally posted by High Lord Gomer
So how hard did Rich slap Nicky after he took him out by sliding the 450 up under him? :scream:

This is from DelMar and I'm pretty sure he pulled it off. The pass not the win :)

 

[Jaybird]

80 is pinned and driving hard, 69 is feathering and hoping he doesn't loose his drive OR become the business end of a dirt track 69.

 

[Ol'89r]

Rich.

That looks like the Del Mar short track last year. King is driving as I described and Nicky appears to be scrubbing off speed by pushing both wheels. He is either trying to intimidate king by showing him a wheel or two or trying to keep from running over the top of him.

If I remember correctly, (which is very unlikely) Nicky finished either 2nd or 3rd with the debut of the CR450f in the main event.

Ol'89r