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Hi,
I read your post a few days ago about the horsepower used to move two bumpers weighing about 50 lbs taking 6-7 horsepower to cart them around on a car.
The formula that you use seem a little bit to simplistic but from the way of your thinking is probably correct.
You have done a lot of modifications to many cars so I will give you that credit to knowing what you are talking about.
Your formula deals with the totality of the amount of work done in the first few seconds of acceleration of which the brake horsepower calculation is base upon. This might be as real as it gets for the first second of inertia.
I raised myself under other terms of horsepower like taxable and drawbar horsepower of the fifties!
This does not mean I know anything about them, but they were standards with lower impressive numbers for sales departments to use.
With the above said, I had a problem with the weight of a standard 240 weighing close to 3,000 pounds and using a standard 110 bhp horsepower engine getting down the road.
The division works out differently for that 50 pound load verus the 430 hp.
There seems to me that a distortion has presented itself in terms of "after the fact" that the car is moving and how little horsepower is being required to keep a move vehicle from point "A to point "B."
Those two points can be one foot in distance to one quarter mile, in your case, or more if a person is looking for miles per gallon of energy used.
In seeing this looming discrepancy troubling my mind and no posts from anybody else, I started questioning myself.
Just in case you wanted to know, I didn't do it out loud, like as if I walking by myself on a cell phone or something, but kept it internally. (:) if I ever start doing that I will keep my hand up by an ear to cool peoples!
I do think a lot because it irritates my wife less if I don't share with her and she has gotten use to it .... Or at least to some extent. (:)
That didn't stop me from searching for other formulas on our beloved Internet.
I found this formula here that left me with just as many unknowns of what is real!
https://sciencing.com/calculate-mechanical-power-6393636.html
You will see from their example it says it take 0.13 horsepower! Quite a discrepancy, huh?
It just says "a mover" and nothing about drag or wheels but an 8 foot distance.
I now understand more about Sir Isaac Newton's laws and getting creditably for his thoughts!
There were two other people playing in the same neighborhood of his mind since him!
Slight variations but he is still correct about his statements.
So with this all going on, I thought I would post to you that power to weight ratio is a safe but overly simplistic formula but works if you accept it for what you need.
My problem is I see it there is a lot of work on the engine not being harnessed except for racing against time.
One of the laws of physics, that seems to ring true, is that in order to do TWICE the amount of work in the SAME amount of TIME it takes FOUR times more POWER to do it!
So, being in a hurry really costs, in investment of mechanical equipment, with lots of depreciation later and not to say, expended energy! 430 hp or 110 hp moved the same car weight.
Bumpers are bumpers or dead weight,that the other tables of taxable and drawbar dealt with in the days of tractors and horses might be a lower number like the one on the site.
I know you are into building up cars, so if you used a lawnmowers engine of say 3.5 BRAKE horsepower could you build a cart to move those bumpers or 50 pounds of dead weight.
I'm willing to say you would say "No Problem!"
That what's bugging me about the two different numbers and the reality!
Just had to share my quirkiness!
Phil
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