Landracing Forum
Bonneville Motorcycle Speed Trials => Bville Motorcycle Speed Trials General Chat => Topic started by: landracing on October 25, 2004, 05:43:00 PM
-
I also would like to see the rear tail section be allowed to go past the edge of rear tire. Also should include not having the rule of no streamlining beyond the verticle line thru the rear axel and top of the rim.
Jonathan
-
Yup, extending the tail past the edge of the back tire would be good -- even if I didn't put a "pointy" tail on the bike, it would sure be nice to NOT have to stress about the body ending first. On my bike it's REAL close when I've got a smaller tire/bigger sprocket combination fitted.
Are these potential or proposed rule changes, or is this just a "wishin'" list?
-
I agree. No one has been able to give a solid answer as to why the tire must extend beyond the back of the tail section. The possibilities are pretty interesting once you consider ride height, side panels and tail section height.
-
I think ECTA allows Plus 3 inches which allow some change in tire size and location. Somewhere here should be the rule
-
I would like to see unlimited
rear length rule with no limitation
on wheel coverage
second choice
4 ft beyond rear tire
3 choice 3 ft beyond rear tire
4 choice 2 ft beyond rear tire
Joe :)
-
Curious as to the thinking behind the current SCTA
bodywork rules. Could they be to reduce the area a
crosswind would act upon?
I'm not sure I'd want a long tail (lever) sticking
out several feet from the contact patch of the rear
tire. Seems like a crosswind gust could get you in
trouble in a hurry. 2 or 3 feet beyond the rear tire
seems reasonable.
Cheers,
Dave, the amateur aerodynamacist :)
-
Dave,
You may be right, but to run on current FIM and AMA rules vehicle may not run for records in any winds on course higher then 3 mph.
Some may not want that you are correct Dave, but we still want the ability to try it out and allow the innovation of the past let us if we wanted to.. Thats all. If there is no advantage to it, then you dont run it, but if a guy wants to the rules will be there to let him.
Jonathan
-
When Can-Am ran their 125cc 137 mph, the fairing they used was evolved from a long series of wind tunnel tests. ( Go back thru your CYCLE MAGAZINE library and read the most expensive story the magazine ever bought, that told of the design process for their fairing. It was even more expensive than the story of the motorcycles, helicopter, Kenny Roberts and Cook Neilsen on Maui.) They decided that the amount gained from the extended length was not worth the possibility of the side forces if the wind in the middle of the course was in excess of that at the starting line. They had a long tailed fairing and a short fairing and they chose to use the short one. Review the Kamm effect. The 3 mph wind rule doesn't protect you from Mother Nature.
Don't wish for something that might come true.
-
freud,
Doesnt protect a streamliner either... but they still run.
Jon
-
Relate the wheel base of a streamliner to a sit up bike. The tail section is much less in proportion than that of a typical motorcycle.
-
Would like to see that article, can you scan and send to me Freud. But I still want unlimited rule on length. Let me be the idiot that learns the hard way. Or let me be the one who goes the fastest.
Jon
-
Originally posted by joea:
[QB] I would like to see unlimited
rear length rule with no limitation
on wheel coverage
Joe :)
Joe I have been successful with my rule changes for the DLRA and we will be able to boat tail at the rear and dustbin at the front from 2006 on :D
Gary (hawkwind racing)
-
I have the can am article.........
my vote it for innovation,
not limitation.......
if I did everything was told I
should do, I ..........well
we wont go there completely.....
but I have no regrets
Joe :)
-
streamliners dont have 10 ft high
tail fins, or tails 20 ft behind the rear
tire, and guess what, they dont have rules
specifically forbidding them from doing so either.................
lets be allowed to innovate........
Joe :)
-
Jon, I'm with you. I'd love to see what a modern
version of the Bert Munro Indian 'liner could do.
Maybe an Unlimited class for sit-on bikes?
Cheers,
Dave
-
Maybe an Unlimited class for sit-on bikes?
:D :D :D
-
I think modifing rules to meet current standards is fine, (i.e. front fairings being allowed past the front axle because street bikes come that way) but wholesale changes would affect the integrity of current records. Things that don't affect performance such as the tire behind the rear bodywork should be eliminated.
For those so inclined, an unlimited open-wheel bike should be allowed to run for time only. Wild as you want, but at your own risk. After all it's just the number we are all looking for. Hey Bill, fire up the welder, it's "Run what you Brung"
-
Larry, these proposals have NOTHING to
do with SCTA rules.........
FIM/AMA only........
Joe :)
-
Joe: My bad: I don't have a copy of the AMA rules. I thought they were based on SCTA or SCTA were based on AMA rules. Aren't the FIM records mostly just by displacement? But dustbins etc. are not allowed. Anyway I don't think the FIM is going to change.
Saw your pic in BRN paper. First time I had a good view. I like the aero, the other half of your speed equation. L
-
THAT'S THE REASONING BEHIND SIDE HACKS
-
Dave,
You may be right, but to run on current FIM and AMA rules vehicle may not run for records in any winds on course higher then 3 mph.
Some may not want that you are correct Dave, but we still want the ability to try it out and allow the innovation of the past let us if we wanted to.. Thats all. If there is no advantage to it, then you dont run it, but if a guy wants to the rules will be there to let him.
Jonathan
The FIM rule is 11 MPH. The 3 MPH is somthing Denis came up with when we were about to make our first run this year. It's not valid under FIM.
-
Ack is correct....FIM 11mph crosswind....................
A long tail/seat was tryed on the 1973 Can-Am
125c.c. record bike.........it got non-rideable at 80mph......even though it look good in the windtunnel..........................as has been noted on this forum before (pay attention people)
DUSTBIN FAIRINGS ARE ALLOWED WITH AMA/FIM
(BUB) as long as the fairing is above axcle height.
(just like the "old" roadrace dustbin fairings of the 1950's)
However, I would like to point out that at this years BUB, our sidecar got blown sideways with a 12mph crosswind (with a Dustbin) We ran with a 3mph crosswind (with a Dustbin) with no problems........so Denis's 3mph rule makes some sense..................................................................................