My contribution (only the Knode issue) [OT]

[Gene Heskett]

On Saturday 06 March 2010, Ed Greshko wrote:
>Gene Heskett wrote:
>> On Saturday 06 March 2010, Ed Greshko wrote:
>>> Les wrote:
>>>> Do you know that the car has a differential or what that does?  The car
>>>> would not work without it, but it is not part of the knowledge you need
>>>> to drive the car.  But you do need to realize that the wheels rotate
>>>> one way on one side and the opposite on the other and that they run at
>>>> slightly different speeds, if you are going to race.  That small bit of
>>>> knowledge along with other similar bits would make you the exception on
>>>> the course and give you an advantage.  It is the same with computers.
>>>
>>> I hate to mention this...but I wouldn't want to have you as my
>>> mechanic.  :-)
>>>
>>> The wheels of a car *do not* rotate one way on one side and the opposite
>>> on the other.  You have simply changed your frame of reference.   Roll a
>>> bicycle forward.  Standing on one side of the bike, the wheels are
>>> rotating clockwise.  Stand on the other, they are rotating
>>> counterclockwise.
>>>
>>> A car would work without a differential in much the same way a wagon or
>>> cart would.  However, when cornering the tires would need to rotate at
>>> different speeds.  This would tend to cause slipping on one side and
>>> dragging on the other and lead to control problems as well as damage to
>>> the tires.
>>
>> Differentials are optional in real racing.  And get less and less
>> important to the vehicles handling as the speeds increase and the corners
>> tighten. In oval dirt track racing, a welded diff is usually good for at
>> least a 3 second quicker lap.
>
>You'd better tell that to the folks at McLaren or the folks at Xilinx
>
>http://www.iloveindia.com/cars/sports-cars/mclaren-f1.html
>has them using a LSD and I don't think it is "acid".
>
Limited slip is a whole new ball game, Craig, no dispute at all,  and not 
something we could engineer into competition go-karts in 1960 at any price, 
we simply could not afford the weight. So we did the next best thing, a solid 
axle turning in bearings mounted to the frame. 12" diameter, 6 inch wide 
slicks on the rear gave us pretty decent traction even on dirt as long as it 
was wet down & packed.  Some of those karts had 40 horsepower on tap when the 
loud pedal went down.  My last one might have been able to find 20 hp running 
on booze.  A 14" deflector head two stroke with rotary intake & all roller 
bearings, it actually belonged on a Navy boat such as the river rats for a 
bilge pump.  Had to spin it about 2k to get it started, and from 3k to 7k, 
get out of its way, and stay out of its way.  But it was also heavy, so while 
I had fun, and really learned how to drive, it didn't bring home the trophies 
no matter how far I tipped the can of dynamite.  Even at my age, I still use 
some of the tricks.  Not all of course, the reflexes that made it work so 
well 50 years ago, just aren't there anymore.

I would like to be a judge in traffic court though, I would sentence the 
sober ones to a summer of campaigning a go kart.  The worst they can do is 
wear out a hard hat & get some road rash, but they would learn how to 
actually drive, in a vehicle small enough that you can make a mistake without 
its costing 10 grand in the body shop.  That experience at finding out what a 
vehicle will do at the limits of traction and beyond, will save them 100,000 
USD in body shop bills later in life.  Note I didn't specify which body they 
would be keeping out of the shop.  I tend to refer to hospitals as body shops 
too.

BTW, those GP & F1 drivers we all admire?  Many started out in go karts.  
Unforch, they have emasculated the whole genre now with those lawn mower 4 
stroke engines.  The ponies aren't there, although some of the high priced 
OHC versions have some potential if you could figure out how to keep then all 
in the same box at the same time.  Kawasaki hasn't figured that out yet, my 
lawn mower has destroyed itself twice in 5 years just doing the grass on this 
smallish lot.  Full of oil both times.  I had a Honda 350F once, it could 
turn 11 grand, and when I threw my leg off it the last time and filled out 
the title for the next guy was when I realized I had put 33k miles on it in 
14 months, it had 57k on it then.  If the new owner kept it full of oil, I 
expect it was still going as strong as ever at 100k miles.  That thing was a 
Timex for me. 

>and
>http://me.queensu.ca/courses/MECH452/readings/documents/reference13.pdf
>
>seems even more complex....

Those folks have long since learned how to meet the weigh limits, and now 
have the privilege of adding a few pounds for such driver aids.  When was the 
last time the FIA re-arranged the F1 rules so we had some real 
experimentation?  Now they all look alike, Honda makes all the engines and 
rents them to the racers.  The devil can be in the details of course, but 
those details can't give a given team even a 5% advantage, its often the .1% 
stuff that wins the race now.

-- 
Cheers, Gene
"There are four boxes to be used in defense of liberty:
 soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)

Too much of anything, even love, isn't necessarily a good thing.
		-- Kirk, "The Trouble with Tribbles", stardate 4525.6