The discussion centers on the acceleration capabilities of lightweight vehicles, specifically comparing motorcycles and cars with high horsepower. It establishes that despite a lightweight vehicle, such as a 300-pound mini car, having the same horsepower as a Top Fuel dragster (7000 HP), it cannot achieve comparable quarter-mile times due to limitations in tire traction and aerodynamic downforce. The Top Fuel dragster, weighing 2320 pounds, benefits from superior traction and design, allowing it to outperform lighter vehicles in drag racing scenarios.
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FactChecker said:If you could get 7000 HP from a small engine motorcycle, that would be impressive. One disadvantage of motorcycles is that they do not have the aerodynamic down-force at high speeds that a top fuel dragster does. The dragster tire traction is higher at the high speeds, but that is not true for motorcycles. Both can easily lay rubber at the beginning, which limits the acceleration they can do, but the dragster can get more traction and accelerate more at high speeds. So a motorcycle will never get the times that a top fuel dragster can (unless you put an upside-down wing on it).
A jet-exhaust-powered vehicle would be different because it is not counting on tire friction for its acceleration.
That would give you a lot of flexibility for putting down-force wings on it. Remember that F=MA, so as long as a larger engine gives more force/pound, it will be better. Also, there is a lot of weight even before the engine is added, so comparing two engines with the same force/pound would give an advantage to the heavier engine. (The vehicle with the heavier engine would have a smaller percentage of non-engine weight. As an extreme example, a 1 oz, 50 HP engine has a great engine HP/weight number, but would not even move the driver very fast. ) I am not sure if top fuel dragsters have weight restrictions in the rules. If not, you will probably find that every single pound more than pays for itself and that their weight is at the optimum.Mohd Abdullah said:I see. But how about, say, a 300 pound mini car? If this small car with very light curb weight have the same horsepower like the Top Fuel dragster, can it or will it acquire the same elapsed time in quarter mile drag race like the Top Fuel dragster always does? Other people said that 300 pound car will simply fly away over the drag strip because of its very light weight but I'm not sure about it. Thoughts?
Remember that the maximum force you can "push" the car with is limited to the friction between the tires and the surface. Since the friction depends on the weight of the car, a light car will probably spin - at least until the rubber in the tires has melted enough to increase the friction coefficient.Mohd Abdullah said:I see. But how about, say, a 300 pound mini car? If this small car with very light curb weight have the same horsepower like the Top Fuel dragster, can it or will it acquire the same elapsed time in quarter mile drag race like the Top Fuel dragster always does? Other people said that 300 pound car will simply fly away over the drag strip because of its very light weight but I'm not sure about it. Thoughts?
FactChecker said:That would give you a lot of flexibility for putting down-force wings on it. Remember that F=MA, so as long as a larger engine gives more force/pound, it will be better. Also, there is a lot of weight even before the engine is added, so comparing two engines with the same force/pound would give an advantage to the heavier engine. (The vehicle with the heavier engine would have a smaller percentage of non-engine weight. As an extreme example, a 1 oz, 50 HP engine has a great engine HP/weight number, but would not even move the driver very fast. ) I am not sure if top fuel dragsters have weight restrictions in the rules. If not, you will probably find that every single pound more than pays for itself and that their weight is at the optimum.
Svein said:Remember that the maximum force you can "push" the car with is limited to the friction between the tires and the surface. Since the friction depends on the weight of the car, a light car will probably spin - at least until the rubber in the tires has melted enough to increase the friction coefficient.
If you try accelerating too fast on a motorbike, the bike will probably flip over backwards ("backwards somersault"). This is due to the torque from the motor and the light weight of the front wheel (draw a diagram and you will see it).
I do not know. What is the friction coefficient between the tires and the ground?Mohd Abdullah said:So, the Top Fuel dragster, despite weigh at 2320 pound, still beat the 300 hundred pound mini car with 7000 horsepower (which is just the same like the horsepower of Top Fuel dragster) in a quarter mile drag race?
No, that is not what I meant to say. Sorry for the confusion. All else being equal, the lighter car will accelerate faster. What I meant is that greater weight of the engine that gives it greater horsepower may make it faster. The "dead" weight of the frame, suspension, etc. does not add horsepower. So the less % of "dead" weight, the faster. Of course, there is a reason for the frame, suspension, etc.Mohd Abdullah said:There is a weight restriction on Top Fuel. Top Fuel dragsters at least must weigh 2320 pounds.
So if I understand you correctly, even a 300 pound mini car that have the same horsepower like the Top Fuel dragster, can't beat the Top Fuel dragster in a quarter mile drag race. Right?
Thought experiment: Assume that the track is slippery ice. Which car will move at all?Mohd Abdullah said:So, the Top Fuel dragster, despite weigh at 2320 pound, still beat the 300 hundred pound mini car with 7000 horsepower (which is just the same like the horsepower of Top Fuel dragster) in a quarter mile drag race?
FactChecker said:No, that is not what I meant to say. Sorry for the confusion. All else being equal, the lighter car will accelerate faster. What I meant is that greater weight of the engine that gives it greater horsepower may make it faster. The "dead" weight of the frame, suspension, etc. does not add horsepower. So the less % of "dead" weight, the faster. Of course, there is a reason for the frame, suspension, etc.
Just considering F=MA: If two dragsters have the same amount of "dead" weight and their engines have the same horsepower per pound of engine, then the heavier engine dragster will be faster. The heavier dragster will have the higher horsepower per vehicle pound.
Svein said:Thought experiment: Assume that the track is slippery ice. Which car will move at all?
With no friction, none of them will move. Less friction means less force to move the car forward.Mohd Abdullah said:I guess the lighter one? Because the lighter car will give less friction.