The Jalopy Journal
Discussion in 'The Hokey Ass Message Board' started by sgtlethargic, Apr 15, 2010.
Are there reasons not to have too short of a wheelbase on a HAMB dragster?
... and, check this out: http://vintage-nitro.com/re-entry-rear-engine-streamlined-dragster/
... Dragfest picture:
You mean like 50 in or something?
Not that short ... right now I've got 78" mockery.
How much power are we talking about? Lippy
Souped up Falcon 170 straight-six ... ha ha ... maybe 200 horses?
I believe that as cars got more motor, they got longer wheelbases to make them more stable and "want" to go straighter off the line. I'll never know how they ran those AA/Fuel Altereds back in the day!!!
what are you building? A Suzuki Samurai?!?!
Well, I suppose if it was real straight and had a plug or two fouled it MIGHT go straight. I'm trying to visualize two yardsticks long....nope. I don't think launching is a problem, it's wide open in the lights bothers me. If it hits a snake turd it'll be a handfull. Lippy
That's what I'm talkin'bout- top end ... maybe a buck, a buck-twenty with a good tailwind.
Make it at least 100" to open your future possibilities.
And 78" is closer to two meters .
Or as my buddy tells me, you'll have plenty of time to figure out what went wrong in intensive care. I agree, all kidding aside, I wouldn't make it shorter than a hundred either. That's pretty fast for a souped up six. If it was 90 in I'd drive it, but I wouldn't tell anyone else to. Lippy
Isn't there a W.B. rule for HAMB cars? Lippy
There are some short wheelbase race cars that go a lot faster.
Back to the top end
Not that a HA/GR is NHRA legal but I believe the NHRA minimum WB is 90"
my rear engine HA/GR is 120" WB, and the driver is pretty cramped.
If I had the power to pull a direct drive I could probably subtract 10", then if I sat the driver position upright a bunch, I might get close to 100"
The shorter the WB the harder to drive. As stated eariler as HP increased so did WB. Had a Flathead Chasies Research dragster in mid sixties with 120 " WD drove well on rough strips.
The driver has plenty of room the way I have mine mocked up.
What, from a physics perspective, is the concern with a short WB? What would make it want to swap ends?
It's not going to break loose on the top end from HP. The CG will be low. The worse things I can think of is if a tire blew, the rear locked somehow, or the brakes (rear only) are mashed and/or biased.
92 is about the safe minimum. My senior Dragster is 96 runs straight no problems. !00 is very good. 120 to 125 is enuf for anything. After that it is my rail is longer then yours , sort of like the boat guys. However the longer a rail is the less suspension it needs. That appeals to some and is understandable.
From a physics perspective, the longer the wheelbase is, the more time it takes for it to get out of shape. Visualize a car with a 100 yard wheelbase, it would take a long time for it to get sideways. It really is that simple.
I agree it's easy to see how a long wheelbase helps. What determines the short limit? If the wheelbase is longer than the track width ...?
I didn't realize cars like the Anglia have a 90" wheelbase (http://www.angliaobsolete.com/history.html).
In the new NHRA rule book:
SECTION 4A – SUPER PRO, PRO, SPORTSMAN
Minimum 85. Maximum wheelbase variation
from left to right: 1 inch. Dragsters: 2 inches. Minimum front tread width: 26 inches on
I'd make it 90" and call it done.
90" is short... and when I came up with the rules for the HA/GR cars, the idea was formed around this car that I had seen at the Nostalgia Drags in Fremont back in the 80's... that had a T frame... I was 13-14 years old, and got it in my head that my brother and I were gonna build one.
Here it is, and I am guessing it is around a 90" wheel base...
If you want to find out how a short wheelbase car handles find a 90" VW dune buggy, that should tell you how long yours needs to be. Ask any woman longer is always better.
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