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Author Topic: Naked & Nasty  (Read 11187 times)
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JackD
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« Reply #15 on: March 10, 2007, 07:14:24 PM »

Dem old guys is sumthin ain't they ?
They might just have a bit of experience to draw on.
"Learning from the experiences of others is a big part of getting old."
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"I would rather lose going fast enough to win than win going slow enough to lose."
"That horrible smell is dirty feet being held to the fire"
bak189
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« Reply #16 on: March 10, 2007, 08:25:53 PM »

In regards to the Can-Am wind-tunnel test......
a complete write-up was done showing the results of the various configuration tested on a rolling test-bed (with the rider on board) The final fairing that was used to set the record can be purchased from Airtech. (Kent has the mold).
In past years I have given copies of the test results to some of the Land Speed Racers that race the small displacement bikes.  I am at the present time away from home, however, if interested sent me a PM and when I get back home after April 5..... I will be glad to send out a copy.  It is very interesting reading.....as far as I know it is the only published study done on
partial streamlined motorcycles. AH, YES, the good old days!!!!!!!!!!!! 

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JackD
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« Reply #17 on: March 10, 2007, 08:42:35 PM »

There have been a number of studies by Universities, Subject Matter experts, OEMs, and Sanction Bodies.
All have reached pretty much the same conclusion.
A lot can be easily learned from the Gravity Powered Vehicle association for example.
The most readable and hopefully understood of all that I have seen is the Cycle article.
You should take BOB up on his generous offer. cool


(I fixed a spello)
« Last Edit: March 10, 2007, 09:13:38 PM by JackD » Logged

"I would rather lose going fast enough to win than win going slow enough to lose."
"That horrible smell is dirty feet being held to the fire"
smcleod007
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« Reply #18 on: March 10, 2007, 08:52:40 PM »

Thanks for the info guys. I first thought Kamm was the fab guy who made Larry's tail. grin After a little Internet search, It's all much clearer now.
Was that a better way to answer ?

"Leading one to arrive at a conclusion you might already have will serve both better and point up any misconceptions for both."

"When you see someone beating their head against a wall, it is important to find out if they are trying to make their feet feel better or knock down the wall.
All of that might be done with a hammer with a better result either way."
.






        Pointing the new guys in motor sports in the direction of pertinent public research is always a smart thing. A lot of peripheral questions will get answered this way.  I think everyone should do their homework when they plan on sharing a potentially dangerous play field with others. wink

I've been searching for photos of the 125cc Can-Am body work. So far no luck. But I have found some very interesting body work used before 1950. Sorry Larry for hijacking your thread.
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JackD
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« Reply #19 on: March 10, 2007, 09:19:11 PM »

It is about streamlining and Larry started it !!!!
I think those "OLD GUYS" are a gang.    LOL
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smcleod007
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« Reply #20 on: March 10, 2007, 09:34:23 PM »

In regards to the Can-Am wind-tunnel test......
a complete write-up was done showing the results of the various configuration tested on a rolling test-bed (with the rider on board) The final fairing that was used to set the record can be purchased from Airtech. (Kent has the mold).
In past years I have given copies of the test results to some of the Land Speed Racers that race the small displacement bikes.  I am at the present time away from home, however, if interested sent me a PM and when I get back home after April 5..... I will be glad to send out a copy.  It is very interesting reading.....as far as I know it is the only published study done on
partial streamlined motorcycles. AH, YES, the good old days!!!!!!!!!!!! 



bak189,  I would definitely like to read that study.

Thanks,  Scott  (smcleod007@msn.com)
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Freud
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« Reply #21 on: March 10, 2007, 11:17:16 PM »

I'll see if I can locate the foto that I did for CYCLE. It looks like space age.

Wasn't it KAMM (a German man) that did the research that stated that the shortened tail section was the
practical compromise to the extended tail?

A fellow named Ritter, who worked with Vesco, rode a 250cc Yamaha above 160 MPH with a copy of the Can Am fairing.

He stepped off at 160 when a crosswind caught him right at the final light on the return run of a USFRA meet.The fairing
was so narrow that he didn't have enough bar movement to compensate. Don asked him before he ran what he would do if the wind caught him. He told Don, "I guess I'll have to step off." At least he had a plan and it worked. He trhew his arms up into the wind and pushed off the pegs. His gloves weren't taped to his leathers. They rolled up and he had two small salt burns on the inside of his wrists and that was all.
He was uninjured and when we made it to the bike that was more than a mile on down the track, the front wheel was still spinning so fast that it burned a groove in my sneaker when I pushed on the tire to stop it from spinning.

The bike passed tech after it crashed.
FREUD
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Since '63
bak189
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« Reply #22 on: March 10, 2007, 11:26:33 PM »

As soon as I return home, Scott, I will get your address and send you a copy..............It should be kept in mind that this study was done in the early 1970's, and I am certain a lot more has been done since that time.  Just one thing that I found very interesting in regards to seat-fairings.....
the sides of the seat (roadracing type) angle
showed best at 30 degrees...with the back of the seat open...and cut-off square.  Very few seats that are being used these days reflect this thinking.  But then again as I noted a lot more has been done since the 1970's.  It's late and this "old" man is going to bed!!!!!!!!!!!!!!!!
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JackD
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« Reply #23 on: March 11, 2007, 01:22:48 AM »

Part of what they learned beyond the performance gain was the cleaner the air stream behind the rider was made the less the next racer could keep up in the turbulent draft.
NASCAR on the other hand loves the draft and the related slingshot because it makes for better crowd entertainment.
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smcleod007
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« Reply #24 on: March 11, 2007, 04:09:13 AM »

What I've gathered so far on the truncated Kamm tail section is, is that the amount of aerodynamic slipperiness gained by tapering out the rear of a vehicle to an aircraft style point or edge makes the vehicle less practical to use on the ground except in a smooth straight line with no wind changes. In a passenger car, storage capacity, ease of access and parking far out weigh a few miles per gallon. What Kamm found was that you don't need to make a long tapered surface to effectively recombine the air as it travels around an automobile. All it takes is that the rear of the vehicle needs to narrow the back end enough to get the recombination flow started smoothly.

Having read an Internet article on Kamm's findings and knowing some basic aerodynamics, this is how I would apply the information towards my safety on a motorcycle zipping around at very high speeds.

Adding a longer tapered tail section in most cases will smooth out the air flow in a straight line.
The safest and quickest way to find your optimum shape and size is to have free access to a 250mph wind tunnel.
Even after designing a perfect slippery tail section in a wind tunnel there's no guarantee Mother Nature is going to let me use it.
The farther the tail extends past the rear axle, the more leverage it will have to move the bike around during bad turbulence or cross winds.
In the air, a plane with a big tail section in bad turbulence or cross winds will pitch and yaw but its not that big a deal since you have 3 axis of control.
Momentary pitch and yaw on a motorcycle at speed is a very bad thing. shocked
That being said. It would seem that the small performance gain from using a long tail section is out weighed by the risk of "loss of control" on a motorcycle at speed.
Am I on the right path here?
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bak189
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« Reply #25 on: March 11, 2007, 01:14:04 PM »

Seeing that we are now on aerodynamics  (Sorry Larry)....as a "old guy" I would like to point that the old vintage type fairings  that we ran in roadracing on bikes with only..........maybe 60hp
on the high side...... had very good aero....One fairing that comes to mind is the "Peel" fairing
developed for the Isle of Man races....this fairing really works.  In today's Vintage Races this fairing is still being used with great success.........
the RC Barker Eng. 500c.c. Norton Manx runs a consistent mid 140mph in the Daytona Vintage Races using a Peel.  I feel a lot of the outstanding
speeds we are seeing today is  horsepower
and not aerodynamics.....this is is somwhat proven by the fact that in order to go really fast one needs around 250lbs over the rear wheel to get traction. Us "old" guys did not have much horsepower to work with.... so we worked on Aero....
Don Vesco understood this better than anyone....
and his many records and roadrace victories prove the point.
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John Nimphius
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« Reply #26 on: March 11, 2007, 01:56:32 PM »

NASCAR on the other hand loves the draft and the related slingshot because it makes for better crowd entertainment.

NASCAR loves anything that keeps cars bunched together and crashing.  On the other hand NASCAR hates anything that resembles real racing.  They're also making a big thing about cheating while any legal innovation that provides an advantage is penalized to make all cars equal again.  This leaves cheating as the only innovation that gives you an advantage you can keep.  At least until you get caught.

John N
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JackD
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« Reply #27 on: March 11, 2007, 02:27:18 PM »

You guys are wonderful.
All of this from the faithful and not the leadership.
It kinda makes you wonder what lead the rulers are taking.
There is hope.
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"I would rather lose going fast enough to win than win going slow enough to lose."
"That horrible smell is dirty feet being held to the fire"
dwarner
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« Reply #28 on: March 12, 2007, 07:45:56 AM »

Bob,

Give me the correct spelling and I'll fix it.

DW
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Stainless1
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Robert W. P. "Stainless" Steele Wichita, Kansas



« Reply #29 on: March 12, 2007, 08:04:55 AM »

Dan, you were supposed to move your clock forward in the spring, not back, you are up and on the computer too early.... rolleyes
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Stainless
Red Hat 228.039, 2001, 65ci, MSA Bockscar Lakester with a little N20 
MSA Bockscar Lakester #1000 my fastest mile 245 and change, 84 ci turbobusa motor... but Corey's 233 MPH H/BFL record is still 3MPH faster than mine.
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