----- Original Message -----
Sent: Sunday, July 09, 2006 1:50 AM
Subject: [FlyRotary] Re: Nothing to do
with Rotary Engines, but....
1 horsepower [international] = 0.999 597 681
horsepower [electric]
The constant for mechanical
[international] horsepower is 33,000 ft-lb/min
The constant for electrical horsepower is
33,013.3 ft-lb/min
The difference between the 2 is quite small - at
180HP the difference is less than 0.1 HP.
180 horsepower [international] = 179.927 582 574
horsepower [electric]
Joe
----- Original Message -----
Sent: Saturday, July 08, 2006 11:29
AM
Subject: [FlyRotary] Re: Nothing to do
with Rotary Engines, but....
What is the equivalent hp conversion of electric to gas engines? I'm
thinking it is about 2:1 (tried to look it up quickly, couldn't find it), so
instead of 180 hp, you would only need 90 hp electric.
Wendell
Subject: [FlyRotary] Re: Nothing to do with Rotary Engines,
but....
Think about how small the alternators on big HP APU's are
and you get the picture on how small you can make a powerful electric
motor if you are willing to work at it a bit. You can easily make a 100 HP
electric motor that weighs 100 lbs. It would not likely be DC,
however.
Electric motors for stationary use have no
constraint on weight. The only reason you would want to make one lighter
would be to save on materials and/or on shipping. If you make a motor of a
given HP lighter, it will cost more, spin faster, or be less efficient
than the heavier motor. If you are running on batteries, you must be
careful not to save weight on the motor by compromising efficiency, only
to add to the total vehicle weight by requiring more batteries to make up
for the reduced motor efficiency.
Bill Dube'
george lendich
wrote:
Hi Bill,
I'm relieved. I won't have to mortgage the house until the technology
advances enough to reduces the weight by a factor of 5. Currently it
looks like I would need about 1400 lbs of batteries. Get it down to
280 lbs and allow 100 lbs for the electric motor and my W&B will work
out about right. :)
I'm looking forward to seeing what you come up with for the aircraft
batteries.
Bob W.
Bob or Bill
I would have thought a 130hp DC Motor would weigh more than 100lbs.
Any rule of thumb on weight of motor to power output ?- I guess there's a
lot of copper windings per HP!?
George (down under)
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