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Author Topic: Team Go Dog, Go! Modified Partial Streamliners  (Read 714828 times)
Rick Byrnes and 6 Guests are viewing this topic.
wobblywalrus
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« Reply #525 on: September 09, 2011, 01:51:59 AM »

Hi Joe.  It is age.  I do not have the energy or testosterone level to be a cocky smart donkey anymore.  It was fun when I could do it.

Tom, the grind #813 cams in the bike now polished up nice during use.  There is no pitting or galling on the lobes or lifters.  They run quiet.  In other words, the cams do not seem to be slamming the valves open and shut.  These cams appear to be well designed.  I like this, so the next cams will be the same brand.  There is another grind I can try and it is the #540 grind.  These cams produces more horsepower and are suitable for the street according the folks that sell them.  I cannot use the standard springs, though.  Racing items will be needed.

Does anyone reading this run a #540 grind WebCam in a Hinckley Bonneville?  Please PM me.

The third and last step in evaluating how I did is the power vs speed chart adapted from Bradley's book.  The new entries are triangles with dots in their middles.  Note that all of my dots for the last four years make a horizontal line.  This shows that my speed increases are due to aerodynamic improvements, learning how to set up and ride the bike, and decreasing the chassis rolling resistance.  I am going faster by increasing efficiency rather than horsepower.


* 2011 Triangles.jpg (387.16 KB, 1006x768 - viewed 207 times.)
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wobblywalrus
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« Reply #526 on: September 11, 2011, 11:54:38 PM »

The last thing I want to do is work on the build.  It would be great to do something else for a few months.  One of my big jobs this year is a front fairing rebuild. The fairing must be on the bike when I do this and it gets cold and wet here in the winter with short days and long nights.  In must do it now before the weather gets bad.

The first step is to rebuild the fairing in front of the handlebars.  It is not as wide as the handlebars and my hands are in the wind.  This is not good and the new front will be slightly wider than the handlebars.  The existing front has an "opening section" in both top and side view.  This splits the wind and shoves it away from the motorcycle.  It also creates a lot of rearward turbulence and a large low pressure area behind it.

The nose section will be rebuilt into a semi-circular shape.  This will split the air, and hopefully, not shove it away from the bike sides.  I want as much airflow as possible to stay attached to the bike.  Also, with this shape there is a reduced area of low pressure behind it.

The goal for next year is to get into the 140's and the aero must work well. 


* Fairing Rebuild 1.jpg (264.34 KB, 768x1008 - viewed 198 times.)
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dadsolds
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« Reply #527 on: September 12, 2011, 11:23:47 AM »

Wobbly,
The way I understand Bradley, its not so much the size of the radius of the front section, but rather what the fairing sides do after you pass the center (radius center mark in drawing) or widest section of the fairing. What seems to be important is that the sides of the fairing begin to close back in towards the center of the bike, both in top view and in side view. The angle of closure should be less than 10 deg to the center line. This angle of closure applies to your body and also the tail section. The greatest drag (neg. pressure) producer is the area at the tail end of what ever is punching a hole in the air. The gradual tapering of the object, bike fairing and rider, helps minimize this area. Take a look at Mellor.


* Tom mellor.jpg (19.1 KB, 640x427 - viewed 217 times.)
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mtkawboy
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« Reply #528 on: September 12, 2011, 11:34:03 AM »

Honda made a Blackbird motorcycle
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wobblywalrus
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« Reply #529 on: September 13, 2011, 12:22:54 AM »

Dadsolds, the overall shape is shown on this drawing I made a year ago.  The back is done and I am working on the front.  Unfortunately I forgot to consider that I would need to turn the bars.  The front is moved ahead a bit and widened slightly to give a teardrop shape, overall.  Now I will be able to turn.  The part I am working on now is the nose right in front of the cutout where my arms and hands are.  The nose is in red on the drawing.  The rules say that all of me should be visible from the side.

On another subject.  Most of the builders I admire use low frames with rigid rear ends.  They lay down on the bikes.  I was going to build a lowboy Triumph.  The choppy track at the last meet showed me the value of properly setup rear suspension.  Now I consider it essential.  Karena Markham, a local rider, and Leslie Porterfield are going fast with tall and short wheelbase production frames on 600cc and 1000cc Hondas.  Now I changed my mind.  The Triumph will be run as a highboy with the production frame and the 3" extended swing arm it has now.   


* Fairing Rebuild 2.jpg (136.21 KB, 1002x768 - viewed 221 times.)
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Koncretekid
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« Reply #530 on: September 13, 2011, 08:43:31 AM »

Bo,
I am going thru some of the same questions that you are, except that I don't have a starting point as my BSA build does not seem to conform to anything now on the market. My view plane thru the headstock will require a large Plexiglass or Lexan bubble in front of this area.  So I will have to start from scratch.  What I see in your top view, is handlebars and footpegs outside of the bodywork.  I think the bodywork needs to envelop these important items which may mean the widest part must be wider and moves rearward, especially on my build.  I also see that you are ending your rear enclosure 7-1/2" rearward of the tire.  This must be FIM, as I have heard the number 11" for BUB (AMA) next year.

I have a question about the plastic bubble.  I see in SCTA that Lexan (polycarbonate) is required for cars for windows, etc.  I have a friend who builds road race fairings, and he claims that Lexan would be dangerous to a bike rider, as it is so strong it could "cut your head off" if you try to go thru it.  He uses only Plexiglas, as it will shatter on impact. I also see that I can buy a better grade shatter resistant acrylic at Lowe's, so that may be my choice.  I can find nothing in the rules for bikes on this subject.  Any thoughts on this?
Tom
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« Reply #531 on: September 13, 2011, 09:01:51 AM »

I'll jump in and agree with Tom that you need to have the fairing extend outward past your hands. This year Brian ran with two different fairings on the front of his bike. The first was a cafe type fairing that was recycled from years past on Tucker's and my bikes. With this fairing he ran consistent 99.xxx mph passes. He swapped to the larger fairing that we made to fit the bike and him and with no other changes made several 102.xxx passes. This experiment proved to us that a full coverage fairing is a worthwhile project.

Tom, on the subject of polycarbonate vs. Plexiglass, I don't believe that Plexiglass is in any way safer than polycarbonate. Yes, it will shatter on impact rather than resist your motion. However, the resulting shards will be razor sharp, and quite probably slice right through anything they encounter, your neck included. Polycarbonate can be formed to with a little heat and patience, and the edges can be sanded round and polished smooth so as not to cut anything. Buy a piece of each and break them, or try to in the case of the poly (wear long sleeves, gloves, and safety glasses when you break the Plexiglass, as it tends to explode when it breaks). If you're worried about hitting it in an accident, mount it so that it will come off if struck from behind, but be secure against wind forces from the front. A bit of thought should provide the answers to how to do this, as I don't have those right now, LOL.
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Ah, this is obviously some strange usage of the word 'safe' that I wasn't previously aware of.  Douglas Adams
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« Reply #532 on: September 13, 2011, 07:03:28 PM »

Tom, I'll second Whizzbang's advice. The shards from plexi are really nasty and may either cut or penetrate. If you're concerned I'd be more inclined to sand smooth all the edges on the polycarbonate (Lexan) windshield and then design a simple breakaway mount.

Pete
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wobblywalrus
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« Reply #533 on: September 13, 2011, 10:34:41 PM »

I am glad you answered that Pete.  Windshield plastic is something I do not know about.

Fortunately the fairing is being built on the bike.  I have the tail on, too.  I can sit on it and make sure there is enough coverage.  Thanks for the advice. 
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Old Scrambler
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« Reply #534 on: September 14, 2011, 09:29:09 PM »

Consider the potential to get your hands as narrow as possible..........I believe the rules allow a minimum of 10-inches between your thumbs.........that says about 15 to 16-inches of fairing width should do.
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2011 AMA Record - 250cc M-PG TRIUMPH Tiger Cub - 82.5 mph
2013 AMA Record - 250cc MPS-PG TRIUMPH Tiger Cub - 88.7 mph
2018 AMA Record - 750cc M-CG HONDA CB750 sohc - 136.6 mph
2018 AMA Record - 750cc MPS-CG HONDA CB750 sohc - 143.005 mph
2018 AMA Record - 750cc M-CF HONDA CB750 sohc - 139.85 mph
2018 AMA Record - 750cc MPS-CF HONDA CB750 sohc - 144.2025 mph

Chassis Builder / Tuner: Dave Murre
wobblywalrus
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« Reply #535 on: September 14, 2011, 11:51:47 PM »

Scrambler, right now I am using the standard switch gear and it is bulky.  I moved the controls and grips in as far as they would go and trimmed the bar ends.  The total width is 25 inches.  A bit on the wide side.

An aluminum bar was bent in a semicircular shape to a 25 inch inside diameter.  This will give the fairing nose immediately in front of the handlebar a 26 inch outside diameter.  The Frankenstien apparatus in the photo is the jig I made to position the bar in the right place.  The new fairing will be built around the old.  Then the old one will be removed.

I sure hope Lars finds his bike.  What a mistake.


* Fairing Rebuild 3.JPG (306.6 KB, 984x768 - viewed 184 times.)
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grumm441
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« Reply #536 on: September 15, 2011, 01:19:12 AM »


 If you're worried about hitting it in an accident, mount it so that it will come off if struck from behind, but be secure against wind forces from the front. A bit of thought should provide the answers to how to do this, as I don't have those right now, LOL.


Indeed
Have a look at how they mount the screens on modern bikes
Plastic screws, or plastic nuts. Or rubber mounted "wel nut"
http://oemfasteningsystems.thomasnet.com/viewitems/pop-well-nuts/pop-well-nut-threaded-inserts
The idea is, in the event of an accident, you hit the screen and it breaks free of the fairing, saving the rider from serious injury
More than once, a bike has turned up at my workshop on a tow truck with the screen off the bike, but intact.
G
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wobblywalrus
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« Reply #537 on: September 16, 2011, 11:32:27 PM »

The p-pad I ordered for a chin rest did not arrive in time for BUB.  I engineered one out of the unused part of a roll of toilet paper, some cord, and duct tape.  Note the loops.  They wrap around the belt.  This way, if the pad squirts out from under the belt it will not fall down onto the salt.  It is always good to design things so there is no chance they will fall off.  The pad is from Drag Specialties.  It is leather and good quality.  These are great for cars and bikes where a small amount of padding is needed.  They come in several colors.   


* P Pad 1.JPG (93.53 KB, 448x299 - viewed 159 times.)

* P Pad 2.JPG (84.79 KB, 448x299 - viewed 154 times.)

* P Pad 3.JPG (85.02 KB, 448x299 - viewed 154 times.)

* P Pad 4.JPG (74.32 KB, 448x299 - viewed 147 times.)
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wobblywalrus
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« Reply #538 on: September 18, 2011, 12:45:33 AM »

This fairing rebuild is a lot of slow and tedious work.  Walrusthink is kept to a minimum.  I do not want to mess this up with my creative ideas and I am trying to follow the concepts in Bradley's "The Racing Motorcycle."  I hope he knows what he is writing about.  The old fairing I am taking off seems to be more streamlined that the new one I am building.  This photo from a ladder shows the shape of the new nose as compared to the old.  The top of the old fairing is removed.  The new nose is larger and it has a semicircular shape.


* Fairing Rebuild 4.JPG (322.96 KB, 1024x683 - viewed 175 times.)
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RidgeRunner
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« Reply #539 on: September 18, 2011, 09:26:56 AM »

Bo,

     If you haven't already, you might want to google up info on the Wixom Bros fairings for roadracing HD's back in the day.  Should ease any doubts you might have about the direction you are taking, looks to me like you are on the right track.  The timeslips will tell.

                     Ed
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