X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from [24.25.9.100] (HELO ms-smtp-01-eri0.southeast.rr.com) by logan.com (CommuniGate Pro SMTP 4.3c5) with ESMTP id 922000 for flyrotary@lancaironline.net; Mon, 02 May 2005 08:09:39 -0400 Received-SPF: pass receiver=logan.com; client-ip=24.25.9.100; envelope-from=eanderson@carolina.rr.com Received: from edward2 (cpe-024-074-189-178.carolina.res.rr.com [24.74.189.178]) by ms-smtp-01-eri0.southeast.rr.com (8.12.10/8.12.7) with SMTP id j42C8pLw021809 for ; Mon, 2 May 2005 08:08:52 -0400 (EDT) Message-ID: <001601c54f0f$b50da040$2402a8c0@edward2> From: "Ed Anderson" To: "Rotary motors in aircraft" References: Subject: Re: [FlyRotary] Re: Ed's new rotor housings Date: Mon, 2 May 2005 08:08:52 -0400 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0013_01C54EEE.2DCC3DB0" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2900.2180 X-MIMEOLE: Produced By Microsoft MimeOLE V6.00.2900.2180 X-Virus-Scanned: Symantec AntiVirus Scan Engine This is a multi-part message in MIME format. ------=_NextPart_000_0013_01C54EEE.2DCC3DB0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Well, Jim We certain will each go in the direction that we feel best meets our = needs. In my opinion, nothing is lost by using a CB instead of a fuse. = Even if its a rare event - whereby a temporary overload condition = exists, once a fuse is blow - that's it, no second chance. However, if = I were going to use fuses in flight critical components (which I won't) = I would certainly make them "slow-blow" fuses. Like I said nothing = against fuses in their place, I do use fuses in non-critical components. Ed ----- Original Message -----=20 From: Jim Sower=20 To: Rotary motors in aircraft=20 Sent: Sunday, May 01, 2005 11:46 PM Subject: [FlyRotary] Re: Ed's new rotor housings I'm not convinced of the utility of Circuit Breakers for flight = critical systems. I would put each of my fuel pumps, the EFIs and what = have you on dedicated circuits, each protected with a HEAVY fuse. My = objective is not to protect my fuel pump in case of a surge. It's a = flight critical component, so I'm going to allow it to go while it can. = The fuse is waaaay heavier than the pump (or whatever) draws, and is = meant to protect the wire going to the mechanism rather than the = mechanism itself. I do not regard fuel pumps as delicate items, so I = don't intend to protect them from transient surges and the like. I will = ride it 'till it drops, and the fuse will blow shortly before the wire = melts. Delicate avionics I might very well protect with CBs. These might = need to be protected from transient surges/voltage spikes (from whence I = cannot say since I have OV protection on my alternator) and the like. Heavy duty, robust components like fuel pumps need no such coddling = IMO ... Jim S. WALTER B KERR wrote:=20 John Slade wrote: My understanding is that the pumps, at least the ones I'm using (or = at least WAS using when I used to be able to fly this #@#$ing thing, = long ago), are designed to run continuously. I have one Walbro Inline = fuel pump-GSL393 (from Tracy) and one Walbro Inline fuel pump-GSL394 = from Lightning Motorsports. Both have metal screw in connectors which = fit AN adapters. They're fused at 20 amps. = ---------------------------------------------------------------------- OK, I'll stir the pot some more. I am not an electrical engineer, = but I do understand the power of redunancy! I will take two separately fused circuits over 1 circuit breaker = every day of the week. If there is a short in my one device or in the = power supply lines, I do not wish to be starting a fire by resetting = circuit breakers while looking for a glider port. I know there are = rotary powered airplanes out there that depend on one circuit breaker = for the entire electrical engine power source that have many, many more = hours of rotary time than me, but I sleep better have two parallel = circuits bringing electrical power to my fused engine buss and then = reduntant pumps on entirely separate fused circuits. My pumps are both = checked during run up and both on during T/O and landing. Bernie >> Homepage: http://www.flyrotary.com/ >> Archive: http://lancaironline.net/lists/flyrotary/List.html ------=_NextPart_000_0013_01C54EEE.2DCC3DB0 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
Well, Jim
 
We certain will each go in the = direction that we=20 feel best meets our needs.  In my opinion, nothing is lost by using = a=20 CB instead of a fuse.  Even if its a rare  event=20 - whereby  a temporary overload condition exists, once a fuse = is blow=20 - that's it, no second chance.  However,  if I were going = to use=20 fuses in flight critical components (which I won't) I would certainly = make them=20 "slow-blow" fuses.  Like I said nothing against fuses in their = place, I do=20 use fuses in non-critical components.
 
Ed
----- Original Message -----
From:=20 Jim=20 Sower
Sent: Sunday, May 01, 2005 = 11:46 PM
Subject: [FlyRotary] Re: Ed's = new rotor=20 housings

I'm not convinced of the utility of Circuit Breakers = for flight=20 critical systems.  I would put each of my fuel pumps, the EFIs = and what=20 have you on dedicated circuits, each protected with a HEAVY = fuse.  My=20 objective is not to protect my fuel pump in case of a surge.  = It's a=20 flight critical component, so I'm going to allow it to go while it = can. =20 The fuse is waaaay heavier than the pump (or whatever) draws, and is = meant to=20 protect the wire going to the mechanism rather than the mechanism=20 itself.  I do not regard fuel pumps as delicate items, so I don't = intend=20 to protect them from transient surges and the like.  I will ride = it 'till=20 it drops, and the fuse will blow shortly before the wire=20 melts.

Delicate avionics I might very well protect with = CBs. =20 These might need to be protected from transient surges/voltage spikes = (from=20 whence I cannot say since I have OV protection on my alternator) and = the=20 like.

Heavy duty, robust components like fuel pumps need no = such=20 coddling IMO ... Jim S.


WALTER B KERR wrote:=20
John Slade wrote:
 
My=20 understanding is that the pumps, at least the ones I'm using (or at = least=20 WAS using when I used to be able to fly this #@#$ing thing, long ago), are = designed to run=20 continuously. I have one Walbro Inline fuel pump-GSL393 = (from Tracy)=20 and one Walbro Inline fuel pump-GSL394 from Lightning = Motorsports. Both=20 have metal screw in connectors which fit AN adapters. They're fused = at 20=20 amps.
 
----------------------------------------------------------------= ------
 
OK, I'll stir the pot some more. I am not an electrical = engineer, but=20 I do understand the power of redunancy!
 
I=20 will take two separately fused circuits over 1 circuit breaker every = day of=20 the week. If there is a short in my one device or in the power = supply lines,=20 I do not wish to be starting a fire by resetting circuit breakers = while=20 looking for a glider port. I know there are rotary powered airplanes = out=20 there that depend on one circuit breaker for the entire electrical = engine=20 power source that have many, many more hours of rotary time than me, = but I=20 sleep better have two parallel circuits bringing electrical power to = my=20 fused engine buss and then reduntant pumps on entirely separate = fused=20 circuits. My pumps are both checked during run up and both on during = T/O and=20 landing.
 
Bernie

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