X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from mail20.syd.optusnet.com.au ([211.29.132.201] verified) by logan.com (CommuniGate Pro SMTP 5.1c.2) with ESMTPS id 1229095 for flyrotary@lancaironline.net; Sat, 08 Jul 2006 18:13:56 -0400 Received-SPF: none receiver=logan.com; client-ip=211.29.132.201; envelope-from=lendich@optusnet.com.au Received: from george (d211-31-236-155.dsl.nsw.optusnet.com.au [211.31.236.155]) by mail20.syd.optusnet.com.au (8.12.11/8.12.11) with SMTP id k68MD3Ud015538 for ; Sun, 9 Jul 2006 08:13:08 +1000 Message-ID: <002401c6a2db$b32287c0$9bec1fd3@george> From: "george lendich" To: "Rotary motors in aircraft" References: Subject: Re: [FlyRotary] Re: Nothing to do with Rotary Engines, but.... Date: Sun, 9 Jul 2006 08:13:09 +1000 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0021_01C6A32F.83ADBE70" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2800.1106 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1106 This is a multi-part message in MIME format. ------=_NextPart_000_0021_01C6A32F.83ADBE70 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Thanks Joe, I was a bit worried for a while, I also thought a 1HP =3D 1HP electric - = seems it's almost 1hp. The big question for me is now - why the = difference? George (down under) ----- Original Message -----=20 From: Joe Ewen=20 To: Rotary motors in aircraft=20 Sent: Sunday, July 09, 2006 1:50 AM Subject: [FlyRotary] Re: Nothing to do with Rotary Engines, but.... 1 horsepower [international] =3D 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] =3D 179.927 582 574 horsepower = [electric] Joe ----- Original Message -----=20 From: Wendell Voto=20 To: Rotary motors in aircraft=20 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.=20 Bill Dube' george lendich wrote:=20 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. =20 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) -- Homepage: http://www.flyrotary.com/ Archive and UnSub: http://mail.lancaironline.net/lists/flyrotary/ ------=_NextPart_000_0021_01C6A32F.83ADBE70 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
Thanks Joe,
I was a bit worried for a while, I also = thought a=20 1HP =3D 1HP electric - seems it's almost 1hp. The big question for me is = now - why=20 the difference?
George (down under)
----- Original Message -----
From:=20 Joe = Ewen=20
Sent: Sunday, July 09, 2006 = 1:50 AM
Subject: [FlyRotary] Re: = Nothing to do=20 with Rotary Engines, but....

 
1 horsepower [international] =3D = 0.999 597 681=20 horsepower [electric]
The constant for mechanical=20 [international] horsepower is 33,000 ft-lb/min
The constant for electrical = horsepower is=20 33,013.3 ft-lb/min
 
The difference between the 2 is quite = small - at=20 180HP the difference is less than 0.1 HP.
180 horsepower [international] =3D = 179.927 582 574=20 horsepower [electric]
 
Joe
 
 
----- Original Message -----
From:=20 Wendell Voto=20
To: Rotary motors in = aircraft=20
Sent: Saturday, July 08, 2006 = 11:29=20 AM
Subject: [FlyRotary] Re: = Nothing to do=20 with Rotary Engines, but....

What is the equivalent hp conversion of electric to gas = engines? I'm=20 thinking it is about 2:1 (tried to look it up quickly, couldn't find = it), so=20 instead of 180 hp, you would only need 90 hp electric.
 
Wendell
 
 
Subject: [FlyRotary] Re: Nothing to do with Rotary = Engines,=20 but....

Think about how small the alternators on big HP = APU's are=20 and you get the picture on how small you can make a powerful = electric=20 motor if you are willing to work at it a bit. You can easily make = a 100 HP=20 electric motor that weighs 100 lbs. It would not likely be DC,=20 however. 

Electric motors for stationary use have no=20 constraint on weight. The only reason you would want to make one = lighter=20 would be to save on materials and/or on shipping. If you make a = motor of a=20 given HP lighter, it will cost more, spin faster, or be less = efficient=20 than the heavier motor. If you are running on batteries, you must = be=20 careful not to save weight on the motor by compromising = efficiency, only=20 to add to the total vehicle weight by requiring more batteries to = make up=20 for the reduced motor efficiency.

Bill Dube'

george = lendich=20 wrote:=20 
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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