horizenjob wrote:
Does this mean you have half the drag of your locost? ( 72 / 90 ) ** 3 = ~.5?
If the double asterisk symbolizes an exponent, that'd be close. Parasite drag increases at the square of the speed difference (90/72 x 90/72 = ~ 1.56) and thrust per horsepower drops directly with the speed increase (72/90 = .8 ), divide the latter number by the former number (1.56/.8 ) = ~.51282051...) indicates pretty darn near half the drag.
horizenjob wrote:
Is that how you figure that out?
Heck no! I figured it out by stepping on the throttle and reading the GPS! YMMV because I had to tweak the governor so the engine would spin to 3600 vs. 3000 but Kubota told me that 3600 rpm is past the power peak for that engine (they also told me I was out of my mind, so I'm not bugging them for a sponsorship) which indicates I'm hitting 90 at somewhat less than 32 hp.
Full disclosure behooves me to acknowledge that the new body has less frontal area than the old body (a windscreen instead of a windshield) but mostly I think it's 'cause the new bod cuts the Cd (based on calculations based on similar vehicles) to less than half the traditional Se7en body.
horizenjob wrote:
I think this is a great way to double the power of your locost.
By the time I'm at highway speeds, that's about what it feels like. I still have to pack a lunch if I want to run the quarter, but with the traditional body and 32 horsepower, I didn't have to pack a lunch--if I didn't mind having just a couple of simple cold cut sandwiches, I had enough time to
make a lunch.
One reason I'm jazzed about making a Miata-powered car is I'm curious how much fuel economy will improve with streamlining. Half the power requirement doesn't translate straight to twice the mileage (engines tend to get less efficient as power demands are reduced) but I wouldn't be shocked to get 50mpg, which would improve my odds of getting to the next Midwest Gathering.