Quote:
Originally Posted by aerohead
Thanks Bob,I'm prone to self-delusion so lets see where my synapses shorted.
I ran calcs for a Miata-sized car of 17.7 square-ft Af,90.93 ft-sec,at Cd 0.30 and 0.10.
Road load @ 0.30 was 8.637 hp
Road load @ 0.10 was 2.879 hp
Delta-HP = 5.757 hp
8.637/2.879= 3 ( this is where I'm getting the 300% ( 2.879 X 3 = 8.637 )
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On the Cd part,
0.30/0.10 = 3 ( 300 % )
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Since Cd was the only variable it was looking like the exercise could be reduced to just comparing Cds,and on a percentage basis.Is this valid?
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Percentages can be tricky. It's all about context.
Cd1 = 0.3
Cd2 = 0.1
Cd1 is 300% *of* Cd2. [multiplicative]
Cd1 is 200% *larger* than Cd2. [additive]
Same for horsepower, and it doesn't change your bottom line as I said before.
(Call me a nit picker but an error of 100% seems hard to dismiss. I thought it was kind of humorous. I hoped you did too. If not, sorry.)
I wonder what my Cd is riding motorcycle...