Return-Path: Sender: (Marvin Kaye) To: flyrotary Date: Sat, 19 Oct 2002 23:35:39 -0400 Message-ID: X-Original-Return-Path: Received: from cpimssmtpu11.email.msn.com ([207.46.181.86] verified) by logan.com (CommuniGate Pro SMTP 4.0b9) with ESMTP id 1832016 for flyrotary@lancaironline.net; Fri, 18 Oct 2002 22:44:05 -0400 Received: from BigAl ([68.7.218.110]) by cpimssmtpu11.email.msn.com with Microsoft SMTPSVC(5.0.2195.4617); Fri, 18 Oct 2002 19:42:46 -0700 X-Original-Message-ID: <006f01c27719$665269c0$6400a8c0@BigAl> From: "Al Gietzen" X-Original-To: "Rotary motors in aircraft" References: Subject: Re: [FlyRotary] Re: EWP Tech Data Take 1,000,002 X-Original-Date: Fri, 18 Oct 2002 19:44:08 -0700 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_006C_01C276DE.B97EAFE0" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2720.3000 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2600.0000 X-Original-Return-Path: alventures@email.msn.com X-OriginalArrivalTime: 19 Oct 2002 02:42:46.0914 (UTC) FILETIME=[35228E20:01C27719] This is a multi-part message in MIME format. ------=_NextPart_000_006C_01C276DE.B97EAFE0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable >=20 > The EWP is the same game. Pump a lot of water and restrict what you > don't need. Simple old school thinking. Don't hink of the EWP as 57 > times more efficient, think of it as only pumping the 1/57th of > coolant that is actually needed at 6000RPM vs 800RPM. It will, of course be very interesting to see the mesured flow rates. = But we must be aware that in the aircraft application, the power output = is pretty much a function of the RPM. And the heat rejection = requirement is a function of power output. So the higher the RPM, the = higher the flow requirement. And we do run at much higer sustained = percent of max power levels than street auto, and higher than most race = applications. We never let up on the gas to go into the turn;or run = like hell for a 1/4 mile and shut it down. In a cooling system with NO head, it will pump 80 litres per=20 minute. Assuming about 3" of head, allowing for cooling system=20 boundary layer friction, it will still pump about 75 litre a minute at=20 full tilt. (which is still about a full RX7 tank of water every = minute!!) It is NOT the FLOW of water through the engine or the heat=20 exchanger that is the issue.=20 It is actually an issue. Water has a certain capacity for carrying heat = (about 11 Btu/min-F), and ethylene-glycol, much less. Assuming you have = an effective air side flow in your rad, you're going to get somewhere in = the range of 15-30 degrees F temp drop in the coolant on a warm day. = Knowing this, and the power output it is quite straight forward to = comput the amount of flow you will need to reject to heat. =20 A 20 F drop coolant drop across the rad will require a flow rate of 32 = gpm of water (or 45 gpm of 50/50 water-eg mix) to handle the heat load = at an engine power level of 200 Hp. A 30 degree drop (difficult to = achieve on a hot day) requires two thirds that much - 21 and 30 gpm. So = if the max flow of the EWP is going to be about 23gpm; I'd suggest not = planning on it for your 20B or your turboed 13B. On a NA 2-rotor, could = be fine.. If, of course, it will run reliably at or near it's max = output for long periods of time. >From what little data I was able to find for the water pump on the 20B, = it will pump about 35 gpm at engine RPM of 6000. Marginal, at best, for = that climbout on a 90 degree day. At altitude, at cruise; the EWP may = be able to handle it. No; I don't have measured data on my airplane because I'm not flying = yet. But having spent years doing engineering analysis on various = nuclear power systems, including some for space application, and where = the analysis had to be backed up by test data; I think I have at least a = reasonable handle on this thing. But if experience with the EWP can = prove me wrong - great. Al Gietzen ------=_NextPart_000_006C_01C276DE.B97EAFE0 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
>
> The EWP is the same game.  Pump a lot of water = and=20 restrict what you
> don't need.  Simple old school = thinking. =20 Don't hink of the EWP as 57
> times more efficient, think of it as = only=20 pumping the 1/57th of
> coolant that is actually needed at 6000RPM = vs=20 800RPM.

It will, of course be very = interesting to see=20 the mesured flow rates.  But we must be aware that in the aircraft=20 application, the power output is pretty much a function of the = RPM.  And=20 the heat rejection requirement is a function of power output.  So = the=20 higher the RPM, the higher the flow requirement.  And we do run at = much=20 higer sustained percent of max power levels than street auto, and higher = than=20 most race applications.  We never let up on the gas to go into the = turn;or=20 run like hell for a 1/4 mile and shut it down.
 
In a cooling system with NO head,  it will pump 80 litres per=20
minute.  Assuming about 3" of head,  allowing for cooling = system=20
boundary layer friction,  it will still pump about 75 litre a = minute at=20
full tilt. (which is still about a full RX7 tank of water every=20 minute!!)

It is NOT the FLOW of water through the engine or the = heat=20
exchanger that is the issue. 
 
It is actually an issue.  Water has a = certain=20 capacity for carrying heat (about 11 Btu/min-F), and ethylene-glycol, = much less.=20  Assuming you have an effective air side flow in your rad, you're = going to=20 get somewhere in the range of 15-30 degrees F temp drop in the = coolant on a=20 warm day.  Knowing this, and the power output it is quite straight = forward=20 to comput the amount of flow you will need to reject to heat. =20
 
A 20 F drop coolant drop across the rad = will=20 require a flow rate of 32 gpm of water (or 45 gpm of 50/50 water-eg mix) = to=20 handle the heat load at an engine power level of 200 Hp.  A 30 = degree drop=20 (difficult to achieve on a hot day) requires two thirds that much - 21 = and 30=20 gpm.  So if the max flow of the EWP is going to be about 23gpm; I'd = suggest not planning on it for your 20B or your turboed = 13B.  On=20 a NA 2-rotor, could be fine..  If, of course, it will run reliably = at or=20 near it's max output for long periods of time.
 
From what little data I was able to find for = the water=20 pump on the 20B, it will pump about 35 gpm at engine RPM of 6000. =20 Marginal, at best, for that climbout on a 90 degree day.  At = altitude, at=20 cruise; the EWP may be able to handle it.
 
No; I don't have measured data on my airplane = because=20 I'm not flying yet.  But having spent years doing engineering = analysis on=20 various nuclear power systems, including some for space = application, and=20 where the analysis had to be backed up by test data; I think I have at = least=20 a reasonable handle on this thing.  But if experience with the = EWP can=20 prove me wrong - great.
 
Al Gietzen
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