worlds fastest motorcycle maybee

[Glen]

The wind conditions are monitored for every run on both courses. The starters and timers work very close on this and relay it to the racer. For MC streamliners A 5 mph cross or diagonal wind and 8 to 10 mph for car streamliners.
The stater asks before each of the runs for a down course report. As the wind can and does blow in different directions along the 8 mile envelop it is critical the drivers/riders be aware of it. I have held many runs up because the wind was blowing at the 4 or 5 mile and not at the 1, 2, & 3 mile. My main concern is the safety of the run.

[JackD]

A small cross wind might be a small problem at a small speed , but make either speed greater and the problem soon gets out of hand.
I made the mistake of asking the starter to call down to the timing stand for a wind reading.
The report was about 3mph ,straight across the track.
The first mistake was that I was not told or didn't listen but the wind was 180 deg. the other way.
That tells you that there is a little low pressure area in the middle.
I was hauling the mail and leaning into the wind.
 At the 1.5 I was rained on for about 100 ft. and then the wind changed direction.
No, I won't take you for a ride to show you.
A sailor can see the wind pattern across the water ahead and use it to an advantage, not so with an LSR vehicle.
Flying also teaches you some things about the weather that are useful for LSR.
 

[tortoise]

I have seen experienced riders running along in a side wind with the liner leaned way over . . .

A technical article (about streamlined bicycles, actually), someone here linked to said that for best stability, center of pressure on bikes should be ahead of the center of gravity, not behind it, as on cars. It makes sense, when you think about it: A side gust from say, the left, on a bike with a rearward center of pressure would lean the bike to the right, but steer it to the left -- not too healthy sounding a situation.

On the other hand, I read somewhere else that with increasing speed, the effective center of pressure moves forward, to actually well in front of the vehicle. Any thoughts, Porkpie?

[sockjohn]

I have seen experienced riders running along in a side wind with the liner leaned way over . . .

A technical article (about streamlined bicycles, actually), someone here linked to said that for best stability, center of pressure on bikes should be ahead of the center of gravity, not behind it, as on cars. It makes sense, when you think about it: A side gust from say, the left, on a bike with a rearward center of pressure would lean the bike to the right, but steer it to the left -- not too healthy sounding a situation.

On the other hand, I read somewhere else that with increasing speed, the effective center of pressure moves forward, to actually well in front of the vehicle. Any thoughts, Porkpie?

tortoise,
I would think this would be a relatively easy experiment to perform on the cheap.  There are lots of inexpensive long wheelbase recumbent to weld up something to mount a panel to prove this out.  Typically eBay has these for like $500 if you don't mind one made of pig iron and junk components.  Certainly cheaper than a trip to Bonneville to find out a theory is wrong.

I think with your name, you need to beat Seldom Seen Slims "high speed run"
http://www.ecta-lsr.com/?page_id=74


Jack - sailing and flying teach good observation skills, which serve us well in life.  Good observation is about as good as actual weather knowledge if applied consistently.

[JackD]

Put a 2ft. square piece of plywood to create more side area, first in the way front, then in the middle, and then sticking out the back of a bicycle and ride it in a slight cross wind.
You might also want to try the same test with no tires, just the wheels.
Be sure someone is available to give you a ride home or wherever and let us know how you do.

[crusher]

MR jack
 How about the rear stabilizer .Should we put one on?Or not?

[JackD]

The effect of the rear stabilizer is to move the CP back much like the feathers on an arrow or tail on an aircraft.
If you shape demands it, you will want one.

[John Noonan]

The effect of the rear stabilizer is to move the CP back much like the feathers on an arrow or tail on an aircraft.
If you shape demands it, you will want one.

Or find out that you may need one..

J

[Sumner]

Crusher I hate to discourage you, but if the only meet you will be able to run is possibly BUB aren't you putting a lot of time and work into something that you might not be able to run unless you have the money to rent the salt for private time??

What if Denis at BUB pulls the plug and says you can't run there??

I do respect the magnitude of the project you have undertaken and wish you all the luck with it.

c ya,

Sum

[Freud]

This discussion of wind makes last years Bub Meet so unique. 3 liners to run and generally wind was not the problem.
That's an amazing record. Among the things that can go wrong at B'ville, wind is the one thing that is invisible and frighteningly dangerous.
Just like 1212, I have seen attempts sit for several days before they surrendered.
You can see the course surface, you can see the mechanicals of any machine but wind
doesn't give you that opportunity and it can be so dangerous.
FREUD

[JackD]

Wind can stop long enough to get you started and start again before you are finished.
FIM for example is a 2 hour window spread over 10+ miles.
The previous World LSR for bikes with the Campos machine finished after sundown in the twilight.

[PorkPie]

On the other hand, I read somewhere else that with increasing speed, the effective center of pressure moves forward, to actually well in front of the vehicle. Any thoughts, Porkpie?
[/quote]

Center of gravity and center of pressure - all this is important - YES.
But what helps if they looks on the right place, when the aerodynamic is wrong.

Exactly this creates the effect you request. If the aerodynamic, especially on the front end, is wrong, the pressure increase "uncontrolled" - with result that the center of pressure moves.

The center of pressure moves always...depends on the speed - more worse the aerodynamic is, so more he moves - but not always forward, he can move also backwards. If this happens your front end start to be weak.

If you got a clean aerodynamic with the right airflow along the car and rip off on the rear end  the moving is so small that there is no effect on the balance of the car.

[PorkPie]

MR jack
 How about the rear stabilizer .Should we put one on?Or not?

When you run a jet engine in a inline two wheeler a fin is necessary to eliminate the effect of the engine torque.

[crusher]

Thanks everyone for your input.To answer Mr sum you have a great website its helped us out alot.As far as what if they don t let us run and Dennis changes his mind .Well  we can not rent the salt we are building this project with the money I make working two jobs with the help of one friend .working 7 days a week.And a understanding wife.And help from a lot of other people.Who all want to see this project succeed .So if anyone thinks we will not make a attempt on the record.They are mistaken.As far as a waste of time.   Nothing  is a waste of time if you used your experience wisely.   Ok  I got that off my chest . We are using  center hub steering.How much king pin inclination should we run?   15 degrees   45 degrees What do you guys think?

[1212FBGS]

25