Paul,
 A BTU is a measure of energy.  Power would be BTU per unit of time.  1
 BTU  =  778 ft-lb

 So, 1 BTU/hr  =  778 ft-lb/hr  =12.97 ft-lb/min  =  3.93 E -4 horsepower

 Inverting this we get:   2545 BTU/hr  =  1.0 hp

 Aubrey

 Hummm you mean if I apply a torque on a stationary bolt for a period of time
 that is energy? How did I miss this in 72 years :) I am not saying
 you are wrong. Far from it. I totally believe you. I must have skipped that
 physics/thermo class. Obviously this is a huge gap in my thermo self education.

 There is no doubt my body would be burning calories.
 If you stood up for a period of time you would be burning calories.

 I thought it had to be rotating to get HP.

 So a BTU is a torque! Wow.

 What is the HP that this oil cooler is dissipating
 when it says 400 BTU's/min? We need about 50 HP for a 200 HP
 rotary.

> Paul Lamar
------------------------------
There seems to be some confusion here -- Aubrey is correct but I don't think
of BTU as a torque.

A BTU is the amount of energy needed to raise 1 pound of water 1*Fahrenheit.

If one HP is converted to thermal energy, it will release energy, and to
keep the coolant at a constant temperature, you would have to dissipate 2545
BTU/hour or 42.4 BTU/min in your heat exchanger. So if your cooler can
dissipate 400 BTU/min, that is 400/42.4 = 9.4 horsepower.


Bill Schertz
KIS Cruiser #4045
N343BS (reserved)

Thanks Bill. That cooler is way too small for a rotary because we need
to dissipate 50 HP in the oil cooler for a two rotor. We would need five
of those coolers. The coolers are about 7" by 8" by 3.5 inches
thick. Too thick to be modern. 195 cubic inches core volume.
If we used four in a rectangular grid it would be about 14 inches
by about 16 inches by 3.5 inches thick with a core volume
of 784 cubic inches. REAL BIG!!! Naw! The stock 2nd gen oil cooler
made by Modine is amazing at only about 250 cubic inches core volume.
Perhaps this cooler does not have turbulators.

We would be lucky to force 45 pounds per minute of air through
it getting it up to only 500 BTU/min.

As I recall the 13B oil pump is 30 gallons per minute or about
165 pounds per minute based on oil being 5.5 pounds per gallon.
I am guessing on the 5.5 pounds per gallon.

This cooler will only pass 55 pounds of oil per minute so the oil circuit
would have to be in parallel if we used more than one I suspect.

I sure wish I could get data like this on the stock 2nd gen
oil cooler or any other brand and size of oil cooler for that matter.