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Old 11-09-2019, 10:10 PM   #1
Thanatos
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Default Defying the laws of physics...

... or, perhaps... understanding them very well, and applying them judiciously:



Yeah... poor quality image - it is a digital scan of a slide that was created nearly 40 years ago.

For those who ride motorcycles, "enthusiastically"... "common knowledge" states that you cannot brake extremely hard, and turn, at the same time. Instant face plant. In the image above, the last time I rode/raced that particular 2-stroke Grand Prix bike, things are getting a little "sporty"... the front suspension is nearly bottomed out, tire almost touching the fairing... if you look carefully, you can see the flat spot on the front tire as it is carrying most of the weight of the motorcycle, while there is very little compression of the rear tire as it is almost clear of the pavement... Yet, my butt is off the saddle on the inside of the bike, and if my leg where out in the normal fashion my knee would be touching the pavement, but on that particular turn there is a high bright yellow painted FIA curb, so my knee is tucked up against the fairing to keep from banging the curb HARD...

(The front fender had been removed because it had been hitting the fairing under hard braking, and disruptive to the handling of the motorcycle)

... at the instant the photo was captured, the bike was still traveling around 110-120mph.

There are the most who believe that racing is about the "adrenaline rush", but the truth is, it is more the test of doing those physics and calculus calculations in a heartbeat, time after time, seamlessly, continually, endlessly...

This is also my first race back after having been bodily lifted by my pit crew and set upon that same motorcycle after running over an oil spill while racing a Production class bike at the end of the prior season, having my left hand lifted to the clip-on handlebar with a fractured hand, fractured shoulder, fractured collarbone, three fractures in the left scapula, and four fractured ribs from a 100+ mph high side... and my right boot lift to the peg with a fractured foot and tibia - then racing that black Yamaha while vomiting into my helmet from the pain, while on the track and at over 160 mph. We did not have body armor and air bags under our leathers like in the current era... hitting the pavement hard at speed generally resulted in multiple fractures.

The bike is a 1978 Yamaha TZ-350E, sourced through the director of the Yamaha Motor Canada factory racing team (not imported into the USA). Lots of "trickery", including the TZ-750 cylinder sourced through none other than Erv Kanemoto
https://en.wikipedia.org/wiki/Erv_Kanemoto
who kinda/sorta had a clue as to how to carve a 2-stroke cylinder...
the carburetors were the exact same Lectron cards as used by Kenny Roberts, the expansion chamber exhaust pipes were specially built Mack Kambayosha (Yamaha USA factory team), and lots and lots of other special bits that enabled the 373cc twin to run about 165 mph, producing something over 80 hp and weighing about 225 pounds.
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Old 11-10-2019, 01:06 AM   #2
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There are more than just one force acting on the bike during a turn, you have centrifugal force, friction and I believe gyroscopic force also helps keep it on the road, not to mention gravity.
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Old 11-10-2019, 02:07 AM   #3
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It ain't the dying I would worry about its living with the pain a day or two after the freaking wreck.
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Old 11-10-2019, 02:39 AM   #4
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Quote:
Originally Posted by aviator View Post
There are more than just one force acting on the bike during a turn, you have centrifugal force, friction and I believe gyroscopic force also helps keep it on the road, not to mention gravity.
Oh, there are more forces than than that.

At that point in the corner, the bike was already leaning over more than 45* from vertical, which means that there was more "centrifugal" force - aka inertia - pushing the bike off of the track than there was gravity holding the bike onto the track, and "friction" - aka tire traction - was being fought over by the two force vectors of braking and turning. The "gyroscopic" effect of both the wheels and the crankshaft are a drain on that tire traction, not an enhancement. With that design engine, the crankshaft rotated in the same direction as the wheels, one added to the other, resisting cornering. It was a year later that Yamaha reversed the rotation of the engine crankshaft, for the purpose of extending piston life past 100 miles in the radically tuned 2 strokes, so that the longer exhaust skirt bore the force of rotation, rather than the shorter intake skirt on the piston... It was realized a couple decades later that the gyroscopic effect of the crankshaft rotating opposite the wheels canceled out each other and made the bikes easier to roll into the corners, thus... less of a drain on that tire traction. In the present day MotoGP bikes, Yamaha is the ONLY manufacturer using an inline 4 cylinder 4-stroke, while the rest of the competition is using variations on the V-4 theme - the V-4s with a shorter crank and less rotating inertia turn in to corners more quickly than the inline 4s, but... Yamaha has reversed crank rotation so that again the crank cancels out the wheel inertia, and the Yamahas flick into corners extremely quickly.

If you have ever attempted to apply the front brake on a motorcycle while leaned over at a 45* angle, much less apply the front brake with sufficient force as to bottom the front suspension, then you have likely experienced a high side crash, the bike flipping you face first into the pavement in the manner of a pissed off gorilla doing a body slam on your dumb ass.

If you have ever done a "stoppy" - braking so violently as to lift the rear tire clear of the pavement - much less doing this at 160+ mph, rushing into a corner...then you are in a very small minority of the population. There is an incredibly fine line between "stoppy" and the accompanying forward endo, and locking the front wheel (even with a racing slick), which for the most of the population means doing an instant face plant when the bike tucks its front end beneath you.

If you can duplicate what is happening in that photo, then you are likely on the path to earning one of these:


which is an international competition license - relatively few hold one of those admission tickets to allow you to measure yourself against the very best in the world.
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Old 11-10-2019, 03:28 AM   #5
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As to the component of "friction" - or tire traction - not only are they using tread compounds in the current day where the tire are as sticky as fly paper when at their operating temperature, and supported by full radial carcasses rather than the stiff bias ply slicks of that long ago era, but... the wheels and tires are more than twice as wide now, as then. The tires put a MUCH bigger footprint onto the pavement than 40 years ago.

If you look at the tread of a current MotoGP bike, the tires is "feathered" (roughed up) to about 3/4" of the edge of the tread, the sharp break between the tread and the concave sidewall. If you are able to see the tires on this still image:

the tires are feathered all the way to the edge of the tread. There is a 1/4 band of the tire between the tread and the concave section of the sidewall; the feathering hangs over the edge. There tires were on the absolute design limit of lean angle, and sliding on the pavement... there was no more lean in the tires, no "safety margin".

That photo was taken a few days after winning a Canadian national championship race, a 350cc bike against the 750cc 2-stroke GP bikes and 1,000cc "Superbikes". Even as high and tucked as were the footpegs, they were being dragged in the corners. There is a "port" cut in the fairing and an exhaust pipe bulges through the fairing... the fairing was cut and lifted higher onto the bike to allow another inch of lean... and it got used.

Quote:
Originally Posted by 4thIDvet View Post
It ain't the dying I would worry about its living with the pain a day or two after the freaking wreck.


This photo was taken at Valley Bend, Westwood Racing Circuit, outside Coquitlam, B.C., a few years earlier, 1976. In that image, I have cut the cast off of a crushed left forearm and wrapped the arm in duct tape so that I could get it inside my leathers, plus have enough strength in my hand to hold onto the handlebar. This is on a 250, chasing soon to be crowned World Champion Stevie Baker, America's first motorcycle road racing world champion, on his home course. With the orange and yellow 350 5 years later, I was leaned over significantly farther, and dragging everything on the right side through that turn, accelerating HARD at about 130 mph. You were right on the ragged edge of washing out the front end, or lighting up the rear tire and high siding, both of which would take you off the track, through the short "run off", up the berm, and launch you into the trees. I had a couple friend die in those trees, and several more were paralyzed.

Tom Nash survived his tour in Vietnam, came back, and was paralyzed from the diaphragm down. It was not just a day or two, but every day for the rest of his life.

In this photo

accelerating hard while still leaned over, you can see the large flat spot on bottom of the rear tire, barely any on the front - the bike is trying to wheelie while still leaned over, those two force vectors of acceleration and turning fighting to overcome "friction", the tire traction... but with very little weight on the front tire, it cuts that tire traction quotient virtually in half. The bike is running wide under acceleration, and that ever present threat of a high side crash is leering, about to collect me up.

As an aside... you can see where the duct tape was layered over the holes in my knees so that I could get through tech inspection, but... by halfway through a race, the holes were worn through again, and my boots would be getting all squishy, filling up with blood. Dragging knees at 150 mph is like holding a belt sander against your flesh. This was in the days before leathers came with "knee draggers"...
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Old 11-11-2019, 01:20 PM   #6
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Old 11-11-2019, 03:06 PM   #7
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Thread on the tire? I never even saw the motorcycle.

Actually I have never ridden a motorcycle, I'm terrified of them. I don't mind throwing an airplane in a spin at 3,000 feet but I'm afraid of motorcycles.
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Old 12-01-2019, 02:27 PM   #8
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Thanatos, did all of those injuries heal properly, or do some of them still haunt you?
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Old 12-02-2019, 11:02 PM   #9
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Quote:
Originally Posted by 500grains View Post
Thanatos, did all of those injuries heal properly, or do some of them still haunt you?
Truthfully? I usually blow it off and say I'm doing fine, but... for a no answer...

I survived better than Wayne Rainey, and many others who are in wheel chairs. I am not.

I was collected up in four separate multi-bike crashes (started by someone else) where at least one other racer died instantly.

"Haunt"? Hmmm... I sustained over 100 diagnosed fractures. I stress diagnosed - every time I get an X-ray, they find a couple more fractures that were never diagnosed, were "non-displaced", and simply healed. I am hardly the only racer who has limped to the start grid with fractures... you cut off the cast and wrap the fracture in duct tape so you can get into your leathers.

I get my monthly Inflecta IV treatment... I am completely stove up with arthritis from all the injuries. I never wanted to count them all. I have difficulty walking... no sense of balance any more. Have not trusted myself to ride ANY motorcycle in 25 years.

Perhaps a dozen concussions... never kept track. Broke three helmets on the pavement. Those nineteen 100+ mph tumbling runs, in an era before body armor and air bags under the leathers, well...they were somewhat detrimental. When I got into my late 50s, all of those fractures in my teeth from my head bangin' the ground so hard... the fractures were opening up and the teeth falling apart. Never thought to wear a mouth guard like a boxer... should have.

As my uncle who raced professionally in the 1950s told me... "If you are not crashing occasionally? You are not racing - you are just in the way." The only way to find the limit is to exceed it, then back off an RCH the next time.

So... yes... I am in constant pain from all of those injuries, but... I also experienced some things that most others do not. I could have chased the dollar and become a doctor, a lawyer, a US Congressman - all mega millionaires - like the others with whom I went to school, but... you make your choices, and you pick your path. No one to blame for the choices that YOU made.

The measure of a life is not the longevity, but the ferocity with which you live it. I have done my best to never live a docile life.

The body is fucked up, but the memories are... sweet.
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