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Author Topic: Team Go Dog, Go! Modified Partial Streamliners  (Read 867282 times)

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Offline wobblywalrus

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Re: Team Go Dog, Go! Modified Partial Streamliners
« Reply #3150 on: September 16, 2018, 08:09:26 PM »
It looks like I will be done on time and have a few hours to visit the NASCAR museum in Mooresville. 

This first picture shows the lower edge of the nearside tail as it was at the BMST.  It was reworked this morning to give smoother air flow as shown in the second pix.

Offline wobblywalrus

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Re: Team Go Dog, Go! Modified Partial Streamliners
« Reply #3151 on: September 16, 2018, 08:13:05 PM »
The seat cover blew off the bike somewhere in Missouri.  A new temporary one was made using a piece of rug and duck tape.  The nose was tasseled.  That was all I could do today.

Offline wobblywalrus

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Re: Team Go Dog, Go! Modified Partial Streamliners
« Reply #3152 on: September 16, 2018, 08:17:26 PM »
All the cockroaches I have known scampered away when the room light was turned on.  The ones around here have no fear of light or people.  This guy kept messing around with my foot.  A shot of carb cleaner calmed him down.  Now I keep the can within reach for self defense.

Offline wobblywalrus

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Re: Team Go Dog, Go! Modified Partial Streamliners
« Reply #3153 on: September 18, 2018, 08:23:17 PM »
There are two wind tunnels in the complex.  The Aerodyn tunnel is the biggest.  It can swivel cars to check the aero in yaw, has jacks to adjust ride height, and can spin the tires during the test.  Big dollar factory teams use this tunnel.  Private people can too if they can afford it.

Motorcycles, bobsleds, bicycles, and other smaller vehicles are tested in the A2 wind tunnel.  It does not have yaw capability, jacks, or tire spinners.  It costs less.  $495 an hour with a 2 hour minimum.  Today I am in it and the US olympic bobsled team will be using the tunnel tomorrow.     

Offline wobblywalrus

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Re: Team Go Dog, Go! Modified Partial Streamliners
« Reply #3154 on: September 18, 2018, 08:25:52 PM »
The tunnel.  Note the huge fans.  The control room.

Offline wobblywalrus

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Re: Team Go Dog, Go! Modified Partial Streamliners
« Reply #3155 on: September 18, 2018, 08:28:39 PM »
The Bonneville as seen through tunnel side windows.  All tests were done with me on the bike.

Offline tauruck

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Re: Team Go Dog, Go! Modified Partial Streamliners
« Reply #3156 on: September 18, 2018, 08:37:55 PM »
Bo, i've never seen anyone put more into a project than you.
You blow my mind. And now you're in all that bad weather to boot!!!!.
You deserve all the success you desire.  :cheers: :cheers: :cheers: :cheers:

Offline Stan Back

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Re: Team Go Dog, Go! Modified Partial Streamliners
« Reply #3157 on: September 18, 2018, 08:47:57 PM »
. . . so how was your blow job?
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Offline wobblywalrus

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Re: Team Go Dog, Go! Modified Partial Streamliners
« Reply #3158 on: September 19, 2018, 08:57:56 PM »
Hi Mike.  The weather fiasco was not anticipated when I left Bonneville to go back east.  It is quite an adventure. 

Actually Stan, I was sucked.

The tunnel was operated by Geoff Eaker, the son of the firm's founder, Gary Eaker.  The streamlining has as close to a NACA shape as I could get and it provides plenty of clearance around the sides of the engine for future turbos, intercoolers, supercharger, etc, I explained to Geoff.

The first trial established a baseline to compare against during the future tests.  The tufts were analyzed along with a smoke test.  I looked through the center of the windshield like I do at Bonneville, with some clearance between my chest and the top of the tank.  About half to 3/4 of my helmet sticks out above the windshield.  Aero drag coefficient was 0.494.

I asked Geoff about the shape of the streamlining.  He said it is OK, except the top of the tail should be higher behind my butt.  It was higher until this year and I had to lower it 'cause of a rule change, I told him.

My plan is to get rid of those Stegosaurus plates and smooth out the finish, I said.  He said it works just great like it is and that effort is not needed.  Later this was discussed with Gary, too.  He said the plate and rivet texture is OK and gave me some sort of scientific explanation I could not comprehend.

Conclusion:  Do not monkey with the shape and leave the riveted plates as is.

I was going to cut aluminum from the top of the fairing and lower the windshield to reduce frontal area, I told Geoff.  The windshield is far more streamlined than me, he said, and it is best to leave it like it is.  Geoff said I need to lower my head.  My chest was on the tank and I just peeked at the horizon through the lowest part of the windshield for another trial.  Aero drag coefficient dropped down to 0.457.  My chest was on the tank for the next trials.

Conclusion:  Keep head down and behind windshield.  Tomorrow or the next day I will post something about the other trials.

Offline Stan Back

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Re: Team Go Dog, Go! Modified Partial Streamliners
« Reply #3159 on: September 20, 2018, 10:34:23 AM »
Very interesting.

It came as a surprise to me as well that some of our long-held assumptions don't hold up.
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Offline wobblywalrus

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Re: Team Go Dog, Go! Modified Partial Streamliners
« Reply #3160 on: September 21, 2018, 08:45:59 AM »
The fans were behind me and pulling air out of the tunnel.  This make sense 'cause it pulls a more uniform mass of air past the bike.  There would be lots of turbulence and non-uniform flow around the scoot if the fans blew into the bike.

The session was the minimum 2 hours.  Eight trials were made.  This involved for each trial 3 minutes of sitting on the bike in a racing crouch perfectly still and 3 minutes with the fans blowing.  In addition, there is the time needed to make changes between the trials.  After the session my leathers weighed about double what they normally do and I was drenched in sweat.  The 2 hour session was all that I could handle physically and I am in good shape for a codger.   Conclusion, schedule two hour sessions on consecutive days if a lot of testing is needed.

The shape was refined to its present by 12 years of work, looking at time slips, and lots of data crunching.  The tunnel was used as a verification of what was done, what is planned, and for calibration of the aero drag coefficient to be used in field calculation.  Conclusion, it might be much more quicker and effective to use virtual modeling to get the bike to the stage where wind tunnel work is productive.

It seems the most potential improvement is based on the rider doing something different.  This is consistent with experience in all of my past racing.       

Offline WOODY@DDLLC

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Re: Team Go Dog, Go! Modified Partial Streamliners
« Reply #3161 on: September 21, 2018, 10:45:56 AM »
WW, small things make big differences some times.
I'll share a wind tunnel experience with a high $$ team. Two riders - same road race bike. One rider bigger than the other rider. Bigger rider would cock his feet on the pegs into the wind and the Cd would go down a few points - smaller rider opposite effect - Cd would go up.  :x :-o :x :-o Bigger rider would put his elbows level to the ground - the Cd would go up - smaller rider - the Cd would go down!  :x :-o :x :-o Who knew?  :? :?
I had a 1979 CB750 Honda street bike that would go 4~5 mph faster with a luggage box on the luggage rack when riding two up! Made the closing air happier!  :cheers:
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Offline stay`tee

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Re: Team Go Dog, Go! Modified Partial Streamliners
« Reply #3162 on: September 21, 2018, 04:03:02 PM »
Yes, as Wood stated, small changes make a difference,, back in the day I drag raced a H2 Kawasaki (the original 2stroke version), by sitting back on the pillion seat from half track on, saw a 5mph improvement in trap speed  :-)
First Australian to ride a motorcycle over 200mph at Bonneville,,,

Offline wobblywalrus

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Re: Team Go Dog, Go! Modified Partial Streamliners
« Reply #3163 on: September 23, 2018, 12:52:18 PM »
The 500cc H1 was too scary for me.  The 750cc H2 must have been a beast to ride.

The baseline Cd was 0.494 with me sitting where I looked through the center of the windshield.  Lowering my head dropped the Cd to 0.457

My leathers were a bit loose before I lost 35 pounds and they are really loose now.  Tape was wrapped around my legs and midsection to make  them fit tighter.  My head was down like during the 0.457 run.  Cd dropped to 0.445  This was the lowest it got.  Conclusion - get leathers taken in so they will fit tighter.

A speed hump was taped onto the leathers behind my head.  My head was down and my leathers were taped.  Cd rose to 0.463.  Conclusion - do not use a speed hump.

The tail was closed at its far end by a flat metal plate.  It was removed.  My head was down, leathers taped, and no speed hump.  Cd rose to 0.453  Conclusion - close the tail end with a flat plate.  The plate was off for the next two tests.

There is a 1'' by 3'' slot at the front of the windshield at its base.  Air flowing into it reduces turbulence around my head.  It was taped shut.  My head wad down, leathers taped, no speed hump, and the end plate was removed. Cd was 0.454  Conclusion - the slot in the front of the windshield does not reduce Cd. 

There is an open area in the belly streamlining to allow the side stand to be deployed.  It was taped shut.  My head was down, leathers taped, no speed hump, with an open windshield slot and an open tail.  Cd was 0.452  Conclusion - the open space for the side stand has an insignificant effect on aero.

Wind speed was 60 mph and data was extrapolated to 175 mph for all tests.     

Offline Frank06

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Re: Team Go Dog, Go! Modified Partial Streamliners
« Reply #3164 on: September 23, 2018, 04:47:07 PM »
There is a 1'' by 3'' slot at the front of the windshield at its base.  Air flowing into it reduces turbulence around my head.  It was taped shut.  My head wad down, leathers taped, no speed hump, and the end plate was removed. Cd was 0.454  Conclusion - the slot in the front of the windshield does not reduce Cd. 

This is something I've often wondered about: thanks for testing.  It sounds like there's no real penalty for having a slot either.  I've also found that a slot in this area reduces turbulence in street riding.

Bo, was frontal area recalculated for the times when your head was down or is this insignificant?