Drat! One of the comments is going to cause me to turnup the turbo boost. The
rolling resistance is higher than I had been using. Yes, I made a MISTAKE! I
was using a formula that dis not include the speed regime under consideration.
I believe the correct formula is the right one to use. It comes from the
"Fundamental of Vehicle Dynamics" by Tom Gillespie, 1992, page 117.
Fr = Fo + 3.24 * Fs * (V/100)^2.5
where Fo and Fs are coefficients found from a table of tire pressure.
Bonneville tires are run at 45 psig or higher to reduce rolling friction but
thats about as high as the graph for the coefficients go. In this case
Fo = 0.008, Fs = 0.002, V = speed in mph
and of course speed = 260 miles/hour
Fr = 0.008 + 3.24 * 0.002 * (260/100)^2.5 = 0.0786
Loss in lbf = Fr * W
W = vehicle weight = apprx 2000lbs
So Loss = 0.0786 * 2000 = 157.3 lbf
Hp loss = Loss * V / 550 = 157.3 * 381.3 /550 = 109.2 hp. (this V is fps, not
mph)
Ok, crap. Well in for a penny, in for a pound. There are mechanical systems
losses also. My famous text indicates about 10 percent mechanical losses which
includes the tranny and rear end. Since I am using a lockup converter it may
not have an effect.
Adding to what I had already calculated as needed horsepower, 481.5 at
Bonneville altitude in August, I have
Flywheel hp = 481.5 + 109.2 + 48.1 = 638.8 hp
Will I ever get this? Who knows! Improvements are an ice cooled Intercooler to
drop the temperature of the engine air charge to ambient or below, increasing
density and adding power. Also, I still have another 50 percent boost from
these turbos according to the compressor maps for the Garrett T03s I am
using.
Now, I know that at least one of you is going to challenge something else, but
please let's make it something new. And remember, that the goal was and is
still to have the fastest Sunbeam on the planet. If that just barely beats he
old Sunbeam streamliner's speed of 203.792, I'll be happy for a while. And
when I drag race it, I want it to be the quickest on the planet. Please note
also, that this is not advertised as a Tiger or Alger or Alpine, but simply as
Sunbeam. I again challenge the mechanically talented of you to bring your cars
to Bonneville standards and meet me there someday. Nothing like a time slip to
make your point.
|