SI, indeed, although I do the car tyres in psi. My school physics
teacher told us not to sneer at those using "imperial units" as the
Americans had got to the moon in feet and inches.
Meanwhile, my co-worker on my re-wire/panel refit job (who is 10
years younger than I am) can only think and work in inches and I have
to use mm. We have a running mutual piss take. (What's a thirty
second? Isn't that half a minute? etc)
Regarding the 60 kts question, the 0.1 psi answer passes a sabity
check if you think about the drag on your hand if you stuck it out of
a car window at 70mph: about 25 sq. in. and o.1psi and a Cd of about
1.0 giving about 2.5lb which seems broadly right. 2psi would have
given 50lbs which would couldn't be right.
Cheers
Willie H
On 12 Mar 2008, at 03:56, D Wysong wrote:
>
> My bad, Troy...
>
> The correct Pd is exactly what I said it was... provided you divide
> the answer by the 32.2 that I inadvertently used. Our good man Willy
> understands slugs (his 'uk' email domain gives him away) and steered
> you in the right direction. The Pd at 60 knots is just shy of 0.1 psi
> (0.08 or so).
>
> Sorry for the bum steer. I should have worked it in SI units to
> double check... ;-)
>
> D
>
>
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