[NSRCA-discussion] Electric sell off

[Dean Pappas]

Hi All,
Good observation John ...
The problem with electric is very solvable and straightforward. I am not saying it will be trivial, though.
Why?
We are used to flying with about 3.5 HP.
If you find that hard to believe, just find Mike Billinton's review of the old OS 140 RX.
In the torque and horsepower curve plot, you find that with a 24" pipe (reasonable) you get close to 3.5
horses at 8,700 RPM or so. If you know someone with a 140 EFI, you will know that that is the typical high RPM recording for a normal flight with a prop that harnesses the engine well. Think 15-3/4 X 11 3-blader or full bladed 17-13.

There are about 750 Wats per horsepower, and our efficiencies are 85 to 90% at best.
That means we need 3000 Watts out of the battery. (think dull orange glow) Then, we will have both vertical and airspeed equal to wet. You will probably consume almost 5 A-H of battery capacity.

Until then, we "gear" the motor and prop combo to get enough thrust with less airspeed.
Such a compromise will always suffer in the wind.

Just remember: you can always recognize a pioneer ... he's the one with arrows sticking in his butt!

later friends,


Dean Pappas
Sr. Design Engineer
Kodeos Communications
111 Corporate Blvd.
South Plainfield, N.J. 07080
(908) 222-7817 phone
(908) 222-2392 fax
d.pappas at kodeos.com


-----Original Message-----
From: nsrca-discussion-bounces at lists.nsrca.org
[mailto:nsrca-discussion-bounces at lists.nsrca.org]On Behalf Of John
Ferrell
Sent: Wednesday, July 26, 2006 4:07 PM
To: NSRCA Mailing List
Subject: Re: [NSRCA-discussion] Electric sell off


There were quite a few "wet" airplanes flying in Masters at the Nats this 
year that did not seem at any disadvantage. Electric looks great, but it has 
its share of warts.

John Ferrell    W8CCW
"My Competition is not my enemy"
http://DixieNC.US