electric motor?

wrote in message
ups.com...

I used 128 cubic inches per gallon. I think that may be right.

Not to be picky, but there are 231 cubic inches in a gallon. Your
engine is a four-stroke, so it will only displace it's volume in two
revolutions, so you need to divide by two. The volumetric efficiency
will depend on throttle setting, making the calculation more difficult.
It is easier to go by way of fuel burn, since the proper ratio of fuel
to air doesn't change much in a gas engine. See above for an example.

I didn't take the time to look it up. I did some really rough calculations
to find out that they are not talking about volume.

Even using your corrected figures, 320ci * 2500 * 60 / 2 / 261 = around
100,000 gallons (91,954). Way more than the 14 times the 8.5 gallons of fuel
I burn in an hour.

I remembered (apparently incorrectly) that 1 cubic inch of water was 1 oz,
and weighed 1 oz.

I vote for a matter to energy converter (safe, of course) that follows
E=MC**2.

In recent years a few electric self-launch gliders have appeared in the
marketplace.
http://www.lange-flugzeugbau.com/htm...tares_20E.html
http://www.apisgliders.com/ApisE.html
http://www.alisport.com/eu/eng/silent_b.htm
However, none of them have the ability to recharge their batteries in
flight.

Wayne
HP-14 "6F"
http://www.soaridaho.com/Schreder



wrote in message
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Montblack wrote:
How much does the 15 minutes of air weigh - that you run through an
(average) rotax engine?

At 4 gallons per hour, the fuel rate is 6*4=24 pounds per hour. (aprox
60% power)

The air / fuel ratio of gasoline engines is about 14 / 1, so the
airflow rate would be 336 pounds of air per hour. At standard
conditions, air weighs about 0.075 pounds per cubic foot, so the air
flow rate expressed in cubic feet per minute would be 336/0.075/60=75
cfm.

tom

wrote in message
ups.com...

Montblack wrote:
How much does the 15 minutes of air weigh - that you run through an
(average) rotax engine?

At 4 gallons per hour, the fuel rate is 6*4=24 pounds per hour. (aprox
60% power)

The air / fuel ratio of gasoline engines is about 14 / 1, so the
airflow rate would be 336 pounds of air per hour. At standard
conditions, air weighs about 0.075 pounds per cubic foot, so the air
flow rate expressed in cubic feet per minute would be 336/0.075/60=75
cfm.

tom


But of course, nearly 80 percent of that air is N2 and stuff that isn't
required for the exothermic reaction with the fuel.

--
Geoff
The Sea Hawk at Wow Way d0t Com
remove spaces and make the obvious substitutions to reply by mail
When immigration is outlawed, only outlaws will immigrate.

Capt. Geoffrey Thorpe wrote:
wrote in message
ups.com...
Montblack wrote:
How much does the 15 minutes of air weigh - that you run through an
(average) rotax engine?
At 4 gallons per hour, the fuel rate is 6*4=24 pounds per hour. (aprox
60% power)

The air / fuel ratio of gasoline engines is about 14 / 1, so the
airflow rate would be 336 pounds of air per hour. At standard
conditions, air weighs about 0.075 pounds per cubic foot, so the air
flow rate expressed in cubic feet per minute would be 336/0.075/60=75
cfm.

tom


But of course, nearly 80 percent of that air is N2 and stuff that isn't
required for the exothermic reaction with the fuel.


Not required for the exothermic reaction, but is required to push the
pistons. The burning gas heats the excess N2, which expands to push the
piston with much lower heat than the welding torch flame that would
result otherwise. If you didn't have all that extra non-reactive mass,
you'd need some way to provide it, lest you melt your piston in very
short order.