WOW !
Tom ,thanks for such a thorough posting .
All of you guys are like this aren't you ?
George in DC
--- "Thomas E. Bryant" <saltracer@awwwsome.com> wrote:
> Group,
>
> I hope that I can explain the formula where it makes
> sense and is useful
> to you.
>
> The idea is to calculate how much air the engine
> requires while covering
> a mile. The cubic inches of air is then converted to
> square inches by
> dividing by 1 mile. This gives you the size of the
> opening in the scoop.
> Naturally this is not absolutely accurate because of
> the variables,
> volumetric
> efficiency, wheel slippage, etc.
>
> The size of the column of air 1 mile long can be
> found by working
> backwards from the distance covered (mile) divided
> by tire
> circumference, equals the number of revolutions the
> wheel makes
> multiplied by the gear ratio to calculate the
> revolutions the engine
> makes while covering the distance, divided by 2
> (since it takes 2
> complete revolutions of the engine to complete the
> firing cycle for all
> cylinders) multiplied by the cubic inches of the
> engine equals the cubic
> inches of air pumped. Now divide this by the
> distance (mile) and you
> have the size of the opening.
>
> Here is the formula for my engine geared for the
> Lakes:
>
> Mile (63,360") / tire circumference (86") x gear
> ratio (3.18) / 2 =
> 1,171.41 x engine size in cubic inches (304) =
> 356,108.64 cu. in. / mile
> (63360") = 5.62 sq in.
>
> I have put this formula in the computer so I can
> plug in gear ratios and
> cubic inches and get instant results.
>
> The higher the gear the smaller the size of the
> opening needed.
> According to Tom Burkland, if the size is right for
> the engine, baffles
> are not needed inside the scoop because the pressure
> is equalized to all
> cylinders. He also said that it is wise to oversize
> a bit, to allow for
> going through the gears, since the calculation is
> for top gear.
>
> Tom, Redding CA, #216 D/CC
>
>
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