I tend to think the stability being influenced more by what I call an
"aspect ratio": wheel base and track of the car. Long skinny cars (ie
stream liners) have a high aspect ratio while short wide cars are low
aspect ratio. I has to do with the displacement of the car in the rear
end when it start to slide out. A small change on a short wide car is a
big angle change through the cg while the same change on a high aspect
car is a small change in directional angle. Gives the drivers more
reaction time. One of my friends and associates at the time trial has a
keith black powered SAAB. He says it is so hard to drive that it needs a
driver with more balls.. He said it is really fun when you break a half
shaft at speed under full power... confirming your notion, lol... I am
currently working on a simulation model for my computer which will be a
full 6dof model trying to determine the importance of aspect ratio or
perhaps other factors for stability.

Another weird notion is that the fast cars have the weight bais which to
me sems backwards. Most are heavy in the rear. On the nature of 40/60
front to rear. I think that turns out to be more for traction than
stability though. Even after I added the weight to the sunbeam the
weight bias is 47/53. Not too bad. Because of where I placed the weight
mass, I made a 17% improvement in the cars moment of inertia, sometimes
called the polar moment of inertia. Hopefully that will give me the tiny
sliver of control to get through bad patches in the salt or where my
foot gets to heavy..

mayf

allan degroot wrote:

>
>
> Basic physics Longer and wider cars are more stable.
>
> Rear wheel drive cars are subject to the "inverted pendulum effect"
>
> Frontwheel drive cars are stable as hell under power, but when that power
> goes away things can get real exciting....
>
> But like you said there is a price to be paid to having the worlds
> fastest
> sunbeam.
>
> AD
>
> At 07:38 PM 7/13/2009, you wrote:
> >Barry, first, I will see if I can rig up a cam corder. The unit I have
> >for the race car use is really not up to video quality in any size you
> >can really see. I will also point you to a video that National
> >Geographic made of my wife and I on our first outing with the car. That
> >was Salt Flats Speedway and was released in 2006. I had cameras
> >everywhere. Someone forgot to tell them though that there is a
> >licensing requirement that has to be satisfied. So it took longer than
> >the first year (well, yeah, I am still trying, lol). One of the
> >videographers came to out home in Pahrump, took lots of footage, had me
> >unload the trailer and reload it and pretend to drive off and then
> >videoed a phony return to the shop after the event. Most of that footage
> >would up on the cutting room floor. It also has the JCB diesel
> >streamliner with Andy Green driving on it. If you can find a copy, it
> >will give you a feel for what goes on.... Yup, WFI was a great movie! I
> >have a couple of local friends that were there when Bert made his
> >runs! They contributed to the money he received from the girls there.
> >And let me tell you, the movie shows absolutely nothing of what really
> >happens today! First, you must get inspected. That can take a day or
> >more because of the number of entries. Then when you go to get in line,
> >the lines are for prestage can be at least 8 hours long. Then stage is
> >another hour or two. Then you make a 2 minute run. There is a lot of
> >wasted time. I also get in a zone. I focus on some distant point and
> >drive toward it. I am alert to every bump and crack in the salt and
> >always wondering if it is gonna spin. The moivie showed Bert getting
> >into trouble on the bike. Well, it does no take that long at all. In the
> >car, you are gaining speed concentrating on keeping it straight then you
> >are a passenger. It takes only milliseconds in a very short car. Longer
> >cars are more diveable but then hey! It wouldn't be a sunbeam, lol...
> >
> >mayf
> >Barry wrote:
> >
> > >
> > >----------------------------------------
> > >
> > >
> > >>To: jyturbo@yahoogroups.com <mailto:jyturbo%40yahoogroups.com>
> > >>From: drmayf@... <mailto:drmayf%40mayfco.com>
> > >>Date: Mon, 13 Jul 2009 07:05:55 -0700
> > >>Subject: Re: [jyturbo] 2009 Sunbeam Land Speed Attempts
> > >>
> > >>I do have one that I will use to verify that the spoiler does not
> affect
> > >>the chute dynamics. As to the driving there is not an awful lot to
> see.
> > >>I am strapped down so tightly that the only thing that moves is my
> arms
> > >>from the elboes out. When the starter says go, I fire it up, check the
> > >>oil pressure, into gear position 2 (1,2,3, no OD) and leave the
> line. I
> > >>start msahing the throttle slowly until speed is up some always
> > >>increasing the throtle. When above 150 mph the sal tis very
> slippery and
> > >>twitchy. I hold th esteerig wheel like it is a live bird with no
> sudden
> > >>inputs from me. The course is at least 100 ft wide, with only mile
> > >>markers to be seen. The salt is flat and white. Not much visual
> > >>reference. I spend most of my time trying to will the car to go faster
> > >>and straighter and not be so twitchy. The next event is pulling the
> > >>chute and that does get me a bit apprehensive. I take my right
> hand off
> > >>the steeering wheel, release the chute hand back to steering and wait
> > >>for th epull. Still maintaing throttle. As soon as the chute blossoms
> > >>and starts pulling then I slowly back off the gas. I never turn th
> > >>emotor off because I do not want to burn up the tranny. When it has
> > >>slowed down to around 100 mph I stab the brakes a few times. When spee
> > >>dis down to about 35 mph I make the turn off coursee o the return
> road.
> > >>I usually go no afarther than the 4th mile before that happens. It is
> > >>not like a road race or even a drag race. Most of the driver input
> is at
> > >>the starting line then the terror begins...
> > >>
> > >>mayf
> > >>
> > >>
> > >
> > > I can see it in minds eye , seen the worlds fastest Indian so never
> > having been on salt it's interesting
> > > reading ( when aI was a child Bert lived nearby) , trust me when I
> say
> > I am sure there is much more happening that the cam would reveal up
> > front , on a bike at over 300k.h concentration forces the mind into a
> > semi zen state and for me the passing slows a little sorts like an
> > accident but it does get very tunnel visioned , know what I mean ?(poor
> > explanation)
> > > anyway with the added wax and some of that there 200mph tape it's a
> > shoe in
> > > will you add some video then as we all love to live vicariously ??
> > >
> > > in anticipation
> > > B
> > >
> > >in Brisbane AU
> > >
> > >
> > >>I
> > >>Barry wrote:
> > >>
> > >>
> > >>
> > >>>By the way have you given thought to a modest cctv cam and hard
> drive
> > for recording the runs , you would learn huge amounts at a modest price)
> > >>>
> > >>>----------------------------------------
> > >>>
> > >>>
> > >>>
> > >>>
> > >>>>To: jyturbo@yahoogroups.com <mailto:jyturbo%40yahoogroups.com>
> > >>>>From: drmayf@... <mailto:drmayf%40mayfco.com>
> > >>>>Date: Sun, 12 Jul 2009 22:09:48 -0700
> > >>>>Subject: Re: [jyturbo] 2009 Sunbeam Land Speed Attempts
> > >>>>
> > >>>>Dale, sadly no, I have not updated the site. But its location is
> > >>>>www.mayfco.com click on the only active link to get to the real
> opening
> > >>>>page then click on that link..
> > >>>>
> > >>>>mayf
> > >>>>Dale McPeters wrote:
> > >>>>
> > >>>>
> > >>>>
> > >>>>
> > >>>>
> > >>>>>Dr. Mayf,
> > >>>>>
> > >>>>>Best of luck to you this year, I hope you get the extra 20 mph.
> > >>>>>
> > >>>>>As stated before a couple of fresh coats of wax should do the
> trick….>J
> > >>>>>
> > >>>>>Have you updated your website lately with all the new changes?
> If so
> > >>>>>please email me a link as I seem to have lost your web address
> again.
> > >>>>>
> > >>>>>Dale
> > >>>>>
> > >>>>>----------------------------------------------------------
> > >>>>>
> > >>>>>*From:* jyturbo@yahoogroups.com
> <mailto:jyturbo%40yahoogroups.com> [mailto:jyturbo@yahoogroups.com
> <mailto:jyturbo%40yahoogroups.com>] *On
> > >>>>>Behalf Of *drmayf
> > >>>>>*Sent:* Sunday, July 12, 2009 8:06 PM
> > >>>>>*To:* tigers@... <mailto:tigers%40autox.team.net>;
> Alpines; PowerStroke@yahoogroups.com
> <mailto:PowerStroke%40yahoogroups.com>;
> > >>>>>tweecer@yahoogroups.com <mailto:tweecer%40yahoogroups.com>;
> jyturbo@yahoogroups.com <mailto:jyturbo%40yahoogroups.com>;
> > >>>>>projectsvo@... <mailto:projectsvo%40yahoo.com>;
> A6intruder@... <mailto:A6intruder%40myo-p.com>; Clint Garrity; Derek
> > >>>>>Fenwick; dcwaterjet@... <mailto:dcwaterjet%40aol.com>
> > >>>>>*Subject:* [jyturbo] 2009 Sunbeam Land Speed Attempts
> > >>>>>
> > >>>>>
> > >>>>>
> > >>>>>
> > >>>>>Well it is almost time to begin final preparations to get the
> Worlds
> > >>>>>Fastest Sunbeam (wannabe) ready to head out to Bonneville.
> > >>>>>
> > >>>>>
> > >>>>>
> > >>>>>
> > >>>>>
> > >>>>>
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