Ballast

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Stayt`ie
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Ballast

Post by Stayt`ie » Fri Jun 10, 2005 11:25 pm

I have worked on this "rule of thumb" (salt) formula with the view that it may help the "newbie racer", establish what ballast he may require.

Ballast = Total required driving force at rear wheel, devided by 10, mutiplied by 4.

Now i ask those of you that have had many years experience racing on "the salt", and are mathmaticaly minded, how dose this formula stack up ??.
First Australian to ride a motorcycle over 200mph at Bonneville,,,

gazza414
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Post by gazza414 » Sat Jun 11, 2005 5:53 am

Amount of "ballast" required is not only traction dependant BUT balance and handling / feel influenced.
What you have put forward is a very simple over view of a basic scientific formula F=uRn.
Oh yer, ballast is limited by loading on suspension components, and of course tyres.
Are you talking about "effective" ballast ? or total ballast?
1 FAST HAYABUSA 217.443mph so far
9 Official Timeslips over 200mph
Very much the apprentice

hawkwind racing
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Post by hawkwind racing » Sat Jun 11, 2005 5:25 pm

F=?? (force) u=? R=? n=? come on Gazza we are not all einsteins :lol:
Ronnie as gazza pointed out where that ballast is placed is actually more important than how much ,yes we use ballast for traction as there is very little drag penalty ( mostly rolling resistance ) , if it is placed directly over the rear wheel this will benifit the traction part very well , but we have to be aware of how this effects our Cof G and ( center of gravity ) and our Cof P ( center of pressure ) ,idealy the mass (ballast ) should be low and forward,so that the Cof P is behind the Cof G for stability reasons especially over 200mph , but the further forward the less over the rear wheel ,so its really an experimental trial and error to locate the ballast where it works best for the vechile and conditions ( alas this will most likely be a comprimise :cry: )
Thanks for the formulae Ill crunch some # 's and see the result
Gary
fastest busa in Captains flat pop. 200

Stayt`ie
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Post by Stayt`ie » Sat Jun 11, 2005 8:22 pm

remember fella`s this is a "rule of thumb" approach.
The reason behind my trying to come up with a formula was that, leading up to the 2004 event (my first as a competitor), i had pretty much all the figures on my bike, eg. horspower, wheelbias, cod, etc. the big unknown was ballast, checked all the photos and read all the articles that i could, no where was there anything of substance on the subject. Do i take 50,100,150,200 pounds, plus as you have mentioned ,ones vehicle has to be set up to take whatever ballest it may require, keeping in mind weight distribution.
So hopefully we can come up with something that will help the first timer out. You are always going to have the "on the day" situation, and that just comes down to experience.
First Australian to ride a motorcycle over 200mph at Bonneville,,,

hawkwind racing
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Post by hawkwind racing » Sat Jun 11, 2005 10:21 pm

well if its of any use ,I tried this last march ( bussa ) filled the frame with 75/80 Kg of lead shot , extended arm 35 kg , another 40kg in steel container mounted low between swing arm and finally another 50 kg on side of swing arm , experimental results - so F@#$n heavy I could hardly get it in or out of the trailer :oops: ,removed the lead from the frame weight to high ,handled like a fat drunk pig , after some low speed runs I removed the 50kg from the side of the swing arm , not happy with the "feel" after a short course run.added a 25kg lead bar low and under wsing arm , run to the 4 mile ,ok no funny handling but only up to 170 mph my last run for the week
for next year Im running a different bike and will be trying a different approach ,it will have aprox 110/120 kg ballast and if neeeded more can be added
Gary :D
fastest busa in Captains flat pop. 200

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Greg Watters
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Post by Greg Watters » Sun Jun 12, 2005 9:29 am

I think the distribution is very important, most of my weight was to the rear this year , pic here shows some of the weight http://photobucket.com/albums/y108/dlra ... 05-053.jpg

I'm sure i was getting a fair bit of front end lift as i had to keep lowering the front for stability,next year the weight will be a little more towards the front.

Stayt`ie
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ballast

Post by Stayt`ie » Mon Jun 13, 2005 9:56 pm

at the 2004 event, my turbo Kawasaki had, wet, including me, frount 46%, rear 54% wheel bias. Now i didnt run the 200mph speeds you fellas did, but during the third mile i was up to 10,000rpm in top, with the gearing i was running, this equated to 203mph, take out wheel slip, lets say a conserative 180mph, and the bike felt as if it was on rails. (had to back it down as i was on my 150mph licenceing pass). My point is wouldn`t 50/50 wheel bias (including ballast) be the safe option ???
as a point of interest i did the exercise on my ZX12 when it was in stock mode, wet, with me suited up, 50/50, i would imagine that the Hayabusa`s would be pretty much the same.
First Australian to ride a motorcycle over 200mph at Bonneville,,,

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Greg Watters
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Post by Greg Watters » Tue Jun 14, 2005 12:16 am

50/50 should be great , i just ran out of time and put the weight where it could potentially do the most good and attach easily,
I was also a bit cautious after Hawkwind had described his drunken pig to me.

gazza414
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Numbers

Post by gazza414 » Fri Jun 17, 2005 8:29 pm

Ronnie these are the numbers for my Stock Road Registered 2002 Busa

2002 Busa/hump /bra/grab rail/full tank/oil/water
weight front 126.8
weight rear 124
Total 250.8kg


My LSR Busa is considerably lighter due to using it as a track bike and has less weight over the back wheel. I havent measured the weight distribution with me on the bike and thats what counts anyway at lower speeds. The weight distribution will change as a function of speed due to the shape of the bike/rider acting like a foil.
This year on the salt I had a linear transducer on the front forks , however the engine management system didnt want to log when it came to the crunch.

Hope to see ya back again on the salt... I remember you now and the black turbo Kawasaki........ there was a chain in the story too.. if my memory serves me correctly.

Good luck
1 FAST HAYABUSA 217.443mph so far
9 Official Timeslips over 200mph
Very much the apprentice

Stayt`ie
Posts: 994
Joined: Fri May 13, 2005 11:47 pm
Location: Mackay

Ballast

Post by Stayt`ie » Wed Jun 22, 2005 10:19 pm

chain ?, what chain??? :oops: I am pretty busy at the moment with dragracing on consective weekends at the regional tracks up here, also making changes to the ZX12, developing a base line . Sooo i`ll get back to the discussion as soon as time allows.
First Australian to ride a motorcycle over 200mph at Bonneville,,,

Stayt`ie
Posts: 994
Joined: Fri May 13, 2005 11:47 pm
Location: Mackay

Post by Stayt`ie » Wed Jul 13, 2005 10:18 pm

ok, i`m back, no racing for three weeks,, i needed a breather...

gazza, i understand the pressure point advancing on a smooth surface (car body, streamliner), but dont you think that it would be lost in the turbulant flow caused by partial streamlining, plus the riders leathers ???. Pity you didnt get readings, as it would be interesting, especially at the speeds you done. Next year a.
First Australian to ride a motorcycle over 200mph at Bonneville,,,

gazza414
Posts: 299
Joined: Mon Apr 04, 2005 11:38 am
Location: NSW

Post by gazza414 » Wed Jul 20, 2005 10:06 pm

The only correct answer I can give is that I dont know, thats why I went with a linear transducer and logger. --next year " If you cant measure it , you cant control it" Cant argue with facts and data. I have seen a pic of a Busa at well over 200mph and the front forks were definately fully extended.
Motorcycle aerodynamics are woeful , hence so many improvements can be made to increase speed without more ponies.
1 FAST HAYABUSA 217.443mph so far
9 Official Timeslips over 200mph
Very much the apprentice

hawkwind racing
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Post by hawkwind racing » Tue Aug 09, 2005 6:20 pm

the experimental "thing" im running for 2006 allows me to add weight over the rear wheel , center of bike and over the front wheel , high or low in whatever combo I need ,hopefully ballast is catered for ,lots of testing and experiments to do at the salt
Gary
fastest busa in Captains flat pop. 200

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