X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from email2k3.itlnet.net ([64.19.112.15] verified) by logan.com (CommuniGate Pro SMTP 5.1c.2) with ESMTP id 1230018 for flyrotary@lancaironline.net; Sun, 09 Jul 2006 19:04:02 -0400 Received-SPF: pass receiver=logan.com; client-ip=64.19.112.15; envelope-from=jwvoto@itlnet.net Received: from rav.itlnet.net (unverified [192.168.10.149]) by email2k3.itlnet.net (Rockliffe SMTPRA 7.0.3) with SMTP id for ; Sun, 9 Jul 2006 18:03:17 -0500 X-Spam-Checker-Version: SpamAssassin 3.1.3 (2006-06-01) on rav.itlnet.net X-Spam-Level: X-Spam-Status: No, score=-1.4 required=5.0 tests=ALL_TRUSTED,HTML_MESSAGE autolearn=failed version=3.1.3 Received: from JWVOTO (unverified [64.19.117.37]) by mail.itlnet.net (Rockliffe SMTPRA 7.0.3) with ESMTP id for ; Sun, 9 Jul 2006 18:03:15 -0500 Message-ID: <007d01c6a3ad$a205da00$72731340@JWVOTO> From: "Wendell Voto" To: "Rotary motors in aircraft" References: Subject: Re: [FlyRotary] Re: Nothing to do with Rotary Engines, but.... Date: Sun, 9 Jul 2006 18:15:17 -0500 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_007A_01C6A383.A17B6660" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 5.50.4133.2400 X-MimeOLE: Produced By Microsoft MimeOLE V5.50.4133.2400 This is a multi-part message in MIME format. ------=_NextPart_000_007A_01C6A383.A17B6660 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable ----- Original Message -----=20 From: Bob Tilley=20 To: Rotary motors in aircraft=20 Sent: Saturday, July 08, 2006 4:19 PM Subject: [FlyRotary] Re: Nothing to do with Rotary Engines, but.... Wendell, Large electric motors have a couple of parameters that protect them. = The first is instant overloads. These prevent these motors from = exceeding a predetermined amperage( thus HP). If a motor is said to be = able to operate at 100 amps then typically the motor instant overload is = set for 200 amps. This allows a motor to RELIABLY start. If IO is = exceeded it will shut down the motor, preventing the good things inside = the motor from coming apart. The second is thermal overloads. This is = usually set around 1.3 times the rated amps. The TO allows you to exceed = the amp rating for a period of time until the thermal capacity of the = motor is in danger. Bill Dube is probably not using either of these to protect the motor = on his bike so he can generate more power but is sacrificing his = RELIABILITY. He is only running the motor for a few seconds so it is = much less important than the use in a plane for example. If you can = determine the continuos HP needed for you to fly at altitude. Then get = there before your engine overloads it's thermal capacity, you can = reliably operate at that HP rating. Hope this helps! Cause HP is HP. Bob On Jul 8, 2006, at 11:58 AM, Ed Anderson wrote: I would hazard a guess that Wendell is probably alluding to the = better energy conversion efficiency of an electric motor over an = internal combustion engine. Assuming the same energy input (whether in = the from of electricity or gasoline) a typical electric motor is around = 50% efficient where as the piston engine is around 25% efficient in = converting input energy to mechanical energy. So for the same energy = input an electric motor should give better conversion efficiency. So = you might get 100 HP out of a motor for a 200HP (electrical energy) = input - whereas to get 100 HP out of a piston engine you would need 400 = HP of energy input (in the form of gasoline) - the rest being "wasted" = in form of exhaust and cooling energy (and some friction). However, I agree with Jarret 1 HP =3D 1 HP regardless.=20 Ed What I was alluding to is the Fact that gas engines produce torque = during a smaller portion of the 360 degree rotation. An electric motor = on the other hand puts out torque for 360 degrees. Hence when using an = electric motor to drive for instance, a pump; instead of a 4hp gas = engine one can use approximately a 2 hp and get the same pumping = efficiency - like amount of water moved. I think I came across the = formula in an old Grainger catalog but it isn't in the one I have now. = FWIW Wendell ( I'll disregard the donkey crap statement for the donkey) ------=_NextPart_000_007A_01C6A383.A17B6660 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
 
----- Original Message -----
From:=20 Bob = Tilley=20
Sent: Saturday, July 08, 2006 = 4:19=20 PM
Subject: [FlyRotary] Re: = Nothing to do=20 with Rotary Engines, but....

Wendell,

Large electric motors have a couple of parameters that protect = them. The=20 first is instant overloads. These prevent these motors from exceeding = a=20 predetermined amperage( thus HP). If a motor is said to be able to = operate at=20 100 amps then typically the motor instant overload is set for 200 = amps. This=20 allows a motor to RELIABLY start. If IO is exceeded it will shut down = the=20 motor, preventing the good things inside the motor from coming apart. = The=20 second is thermal overloads. This is usually set around 1.3 times the = rated=20 amps. The TO allows you to exceed the amp rating for a period of time = until=20 the thermal capacity of the motor is in danger.

Bill Dube is probably not using either of these to protect the = motor on=20 his bike so he can generate more power but is sacrificing his = RELIABILITY. He=20 is only running the motor for a few seconds so it is much less = important than=20 the use in a plane for example. If you can determine the continuos HP = needed=20 for you to fly at altitude. Then get there before your engine = overloads it's=20 thermal capacity, you can reliably operate at that HP rating.  = Hope this=20 helps! Cause HP is HP.

Bob

On Jul 8, 2006, at 11:58 AM, Ed Anderson wrote:
I would hazard a guess that Wendell is = probably=20 alluding to the better energy conversion efficiency of an electric = motor=20 over an internal combustion engine.  Assuming the same energy = input=20 (whether in the from of electricity or gasoline) a typical electric = motor is=20 around 50% efficient where as the piston engine is around 25% = efficient in=20 converting input energy to mechanical energy.  So for the same = energy=20 input an electric motor should give better conversion = efficiency.  So=20 you might get 100 HP out of a motor for a 200HP (electrical energy) = input -=20 whereas to get 100 HP out of a piston engine you would need 400 HP = of energy=20 input (in the form of gasoline) - the rest being "wasted" in form of = exhaust=20 and cooling energy (and some friction).
 
However, I agree with  Jarret = 1 HP =3D 1=20 HP regardless. 
 
Ed

What I was alluding to is the Fact that = gas=20 engines produce torque during a smaller portion of the 360 degree = rotation. An=20 electric motor on the other hand puts out torque for 360 degrees. = Hence when=20 using an electric motor to drive for instance, a  pump; instead = of a 4hp=20 gas engine one can use approximately a 2 hp and get the same pumping=20 efficiency - like amount of water moved.  I think I came across = the=20 formula in an old Grainger catalog but it isn't in the one I have=20 now. FWIW
Wendell ( I'll disregard the donkey crap = statement=20 for the donkey)
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