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Author Topic: Team Go Dog, Go! Modified Partial Streamliners  (Read 641350 times)
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bak189
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« Reply #570 on: October 14, 2011, 09:30:21 AM »

Everybody is a expert.......just screw it down, and fire it up....it is not rocket science.............................................................................
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wobblywalrus
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« Reply #571 on: October 16, 2011, 10:34:43 PM »

These metal fairings are not as rigid as they appear and internal braces are a must.  First, I have a lot of metal laying about so I can select a piece of just enough thickness.  There is no need to use overly thick stock because it is all I have.  Second, the braces are carefully thought out so they are in the right location to give strength and not be in the way when I need to do maintenance in the area.  Third, any excess material is milled or drilled off.  These corner brackets for the dashboard are an example.


* Fairing Rebuild 20.JPG (204.34 KB, 767x600 - viewed 166 times.)

* Fairing Rebuild 21.JPG (238.17 KB, 800x533 - viewed 209 times.)
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Koncretekid
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« Reply #572 on: October 17, 2011, 06:15:31 PM »

Bo,
What is the size of the stock (aluminum?) that you are using?  Is it predrilled or are you drilling it for lightness?  Also, if it is aluminum, what grade, and are you having to anneal it to bend it?  I don't remember having quite that great a  selection in my erector set.
Tom
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wobblywalrus
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« Reply #573 on: October 17, 2011, 10:49:31 PM »

The bars are 1/2 inch by 1/2 inch.  The gussets are 1/8-inch plate.  The braces are 0.100 inch plate.  The sheet is 0.020 inch sheet.  I will try 0.015 on the new fairing.

Almost all of the bars, billet, and angles I can get here are T6061.  Magnesium and silicon are the major alloying ingredients.  These are good alloys for general purpose use and they resist corrosion.  Most of these have T6511 temper as supplied.  This is a strong temper and I only anneal them when I am bending around a sharp radius.

Aluminum metallurgy is complex and fascinating.  Try to find Bradley's book "The Racing Motorcycle" Volume 2 used or new on the internet.  He says a lot about alloys, tempers, welding it, etc. in easy to understand language.  For example, from his chart, the 6061 alloy in T6 temper has a 310 newton per square millimeter tensile strength and it drops to 124 N/mm2 when I anneal it to O temper.  This is why I do not anneal the metal unless absolutely necessary.

I drill everything.  Nothing is predrilled

My knowledge about aluminum makes me use friendly, easy to understand, and predictible steel for the steering stem, axles, footpegs, handlebar, swingarm pivot bolt, engine connecting rods, and the frame.  Nuts and bolts, too.



 
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wobblywalrus
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« Reply #574 on: October 23, 2011, 12:03:07 AM »

My middle son is in afganistan.  They captured a couple of people today.  This is unusual.  The taliban usally fight to the death.  Neither of the two spoke afgani and they both had pakistan money.  My son thinks this war is entering a new phase.

On a lighter note.  Here is our 2012 team photo. 


* Team Photo.jpg (188.78 KB, 1024x721 - viewed 214 times.)
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wobblywalrus
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« Reply #575 on: October 24, 2011, 11:31:09 PM »

"The front fairing must start as far forward as possible and should shroud the wheel as mch as possible within the regulations.  Look at the Honda NSR500 and NSR 250 in Fig 4.36" says Bradley in his discussion about streamlining.

The dustbin style fairing used in the 1950's is the most aerodynamically efficient and it encloses and shrouds the front wheel.  The regulations I race under say "A front fender is compulsory..."  This means I must use a more conventional setup.  Sorta like the fronts of the road race bikes in Bradley's two examples.  The front edges of the fairing is shown in the two photos and it will partially enclose the whee.  The drilled bars are where the edges will be.  The opening is big to allow room for the forks and wheel to turn.

The new fairing will allow a lot more air to pass over the engine.  This is good.  The new motor will have a lot more displacement and compression and I need to keep it cool.


* Fairing Rebuild 22.JPG (183.52 KB, 640x465 - viewed 183 times.)

* Fairing Rebuild 23.JPG (144.68 KB, 640x461 - viewed 180 times.)
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Peter Jack
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« Reply #576 on: October 25, 2011, 01:52:56 AM »

Do the rules specifically rule out a dustbin fairing. You could always run a conventional front fender within the dustbin. When I'm trying to enforce the rules I hate guys like me! evil evil evil

Pete
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Unkl Ian
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« Reply #577 on: October 25, 2011, 02:33:56 PM »

For example, from his chart, the 6061 alloy in T6 temper has a 310 newton per square millimeter tensile strength and it drops to 124 N/mm2 when I anneal it to O temper.  This is why I do not anneal the metal unless absolutely necessary.





Welding will do the same thing in the heat affected zone.
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bak189
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« Reply #578 on: October 25, 2011, 03:47:30 PM »

At the BUB Trials one can run a Dustbin fairing, as long as it is mounted even or above the front axcle...(solo bikes only)
Sidecars the Dustbin can be below the front axcle..............................

Even when using a Dustbin I would mount a front fender to keep the salt spray out of your helmet and face.....................................................





















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wobblywalrus
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« Reply #579 on: October 25, 2011, 11:47:05 PM »

Thanks for the advice about dustbins.  Two questions.  How does air get into the engine bay?  Those things were banned from world road racing due to handling problems.  Did anyone figure out a cure?

I am committed to the current design.  I want to get the frame done so I can take it off and move it indoors before the weather turns real bad.  The skin will be hammered out and riveted on in the warm cellar with some nice music playing.
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bak189
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« Reply #580 on: October 26, 2011, 09:44:13 AM »

Dustbin fairings were banned from International Roadracing on solo bikes
for two reasons.......one being cross winds.....but the main reason was
that during a long roadrace exhaust would build up inside the fairing affecting the rider.
If I were to run a dustbin fairing on a solo bike......I would certainly not make a run at any of the LSR events if there was  wind......certainly any cross winds.  We have for many years used a dustbin on our LSR
sidecar outfit......but in the last couple of years on the salt the winds have increased to the point that we feel it is too dangerous to run that type of fairing.

 
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« Reply #581 on: October 27, 2011, 12:12:49 AM »

Thanks for telling me this bit about history.  I never thought exhaust would be a problem.  Now I see how it could be one.

A comment on the subject of annealing aluminum during welding.  Years ago I was witness to some aluminum chassis fabrication.  The frame and swing arm were sent out to be "pickled."  As best as I know, the chassis was retempered by immersing it in a hot liquid.  Bradley in his book "The Racing Motorcycle" Volume 2 gives a lot of advice about welding and retempering aluminum alloys.

Up here in the woods it is hard to get good advice about anything related to racing.  I read books and magazines to learn.  This was easy when Borders Books was in business.  This was a big book store with an in-house coffee shop.  I could sit down and browse through books and read the tidbits I needed.  They went belly up.  I had to find a new method to get books and I can afford to buy only a portion of the ones I need.  This is what I do now.  An example.

New radial tires are developed with rubber compounds having less internal friction when flexed.  Does this reduce rolling resistance?  This is what I want to know.  First, I look up "Motorcycle Tire" in Wikipedia.  These sentences are in the lengthy article.  "Rolling resistance is the resistance when a tyre rolls on a flat surface.  The rolling resistance coefficients of motorcycle tyres are about 0.02[1]."

The [1] is a link to a reference note.  I click on it and this comes up.  "Cossalter, Vittore (2006), Motorcycle Dynamics (Second Edition ed.) Lulu.com pp 37-72, ISBN 978-1-430300861-4"  THis is the reference note.  It describes the book.  I copy it.

Now I open http://openlibrary.org/  This is an internet library.  I type the ISBN number into the search box.  I separate the numbers with dashes just like on the previous paragraph.

Up pops a few choices.  One is a link to a scanned copy.  There is not one for this book.  I could read it on-line if there was.  That sometimes happens.

Another choice is a list of people who sell the book.  I click on Powells Books.  They are in Portland and if they have a copy on the shelf I can peek inside.  They do not.  The books are in a "remote warehouse." 

A further choice is a list of libraries that have a copy.  There is one in Eugene.  That is not far from my house.  I will go down to the local library, give the librarian the mooneyes, and sweet talk her into getting me a copy on inter-library loan.  She does this sometimes when she feels like it.

A fellow can race when almost broke.  It just takes some creative thinking.

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Peter Jack
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« Reply #582 on: October 27, 2011, 12:31:14 AM »

Sometimes E-Bay works too. It's variable.

Pete
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Unkl Ian
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« Reply #583 on: October 27, 2011, 02:58:09 PM »

New radial tires are developed with rubber compounds having less internal friction when flexed.  Does this reduce rolling resistance?  This is what I want to know. 


I think the benefit is in the carcass construction, not the rubber compound.
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« Reply #584 on: October 31, 2011, 09:33:37 PM »

Ian, I think it is silica or something similar in the rubber in addition to the radial carcass.

This is something I learned from Rick Murray.  Rick and his wife, Nida, race a grand prix sidecar at BUB.  These countersunk pop rivets are developed for aircraft and they do not project out into the wind and cause drag.  Today is the first time I have used them.  The picture shows the head shape.

Another picture shows a bar with holes in it.  Every third hole is for a pop rivet.  The larger holes are for weight reduction.  I put a 60 degree wood screw countersink bit in the cordless drill and I bevel each hole.  The bevel works best if I tilt the drill a bit to the side and swing the drill around in a full circle when I am using it.  This gives the bevel a shallower angle than if I go straight in.

The rivets are installed in a picture.  Note how the heads pull the sheet metal down into the bevels.  The rivets do not stick out.


* Fairing Rebuild 24.JPG (131.09 KB, 637x480 - viewed 164 times.)

* Fairing Rebuild 25.JPG (154.18 KB, 640x463 - viewed 165 times.)

* Fairing Rebuild 26.JPG (75.07 KB, 448x311 - viewed 176 times.)
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