Return-Path: Received: from imf16aec.mail.bellsouth.net ([205.152.59.64] verified) by logan.com (CommuniGate Pro SMTP 4.3c1) with ESMTP id 726065 for flyrotary@lancaironline.net; Sat, 12 Feb 2005 08:20:33 -0500 Received-SPF: pass receiver=logan.com; client-ip=205.152.59.64; envelope-from=sqpilot@bellsouth.net Received: from [209.214.44.107] by imf16aec.mail.bellsouth.net (InterMail vM.5.01.06.11 201-253-122-130-111-20040605) with ESMTP id <20050212131940.TLQC1983.imf16aec.mail.bellsouth.net@[209.214.44.107]> for ; Sat, 12 Feb 2005 08:19:40 -0500 Received: from 127.0.0.1 (AVG SMTP 7.0.300 [265.8.7]); Sat, 12 Feb 2005 07:19:31 -0600 Message-ID: <018c01c51105$7bd2ac00$6b2cd6d1@paul52u7f5qyav> From: "Paul" To: "Rotary motors in aircraft" References: Subject: Re: [FlyRotary] Vapor lock Date: Sat, 12 Feb 2005 07:19:29 -0600 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 Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="=======AVGMAIL-420E02630DD3=======" --=======AVGMAIL-420E02630DD3======= Content-Type: multipart/alternative; boundary="----=_NextPart_000_0189_01C510D3.3116D150" ------=_NextPart_000_0189_01C510D3.3116D150 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: quoted-printable ----- Original Message -----=20 From: Perry Mick=20 To: Rotary motors in aircraft=20 Sent: Friday, February 11, 2005 11:36 PM Subject: [FlyRotary] Vapor lock One final thought.....my aluminum sump tank in not vented. Seems we = discussed this at length when I was building this thing, and since the = overflow is pumped into the sump tank, the fuel might just be pumped = right out of the vent. Take care. Paul Conner Paul, I think this is your problem. I brought this up on this list = once before. I nearly had the makings of a fatal accident a year ago = when I temporarily had my sump tank unvented. I had been flying for over = four years with a vented sump tank and never had a problem.=20 I flew to Puyallup WA for the airfaire early in the morning. The plane = sat out in the sun all day, with temperatures rising. When I went out = early afternoon to depart, I lifted the nose, hopped in, started the = engine, taxied to active runway. Very fortunately there were several = planes in the pattern and I had to wait for takeoff. Finally, I took the = active, pushed in full throttle - and the engine died. This had never = happened before. I got out and pushed it off the runway, somewhat = stumped. Finally I remembered the rubber cap I had put on the sump tank = vent. I popped it off and heard a "poof" sound, and then the sound of = fuel flowing into the sump tank. My sump tank is mounted low, fed from = the main tank by gravity. Apparently being parked nose down for several = hours out in the sun allowed vapor lock to form in the lines between the = main tank and the sump tank. If those planes had not been in the = pattern, I would have taken off from a relatively short field in a = congested area and the engine would have quit right after takeoff with = no place to land safely. My sump tank vent is up at the top of the fuselage with the main tank = vents, I never have problems with fuel being pumped out the vent. I now = maintain that the sump tank must be vented - to do anything else may be = fatal. I've brought this up before on this list and more recently on = Canard Aviators. Perry Hi, Perrry....One question....Does your unburned fuel (from the fuel = rail) go back into your sump tank also? Or do you return the unused = fuel to one of your fuel tanks? If I were returning fuel to one of the = main tanks, I would think that venting the sump would be appropriate, = but since I am sending fuel undere pressure back into the sump tank, I = am concerned that once the sump tank is full, the additional fuel pumped = back into the sump tank would take the path of least resistance....out = the vent instead of back up the fuel line into the tank? Thanks for = your input. Paul Conner -------------------------------------------------------------------------= ----- No virus found in this incoming message. Checked by AVG Anti-Virus. Version: 7.0.300 / Virus Database: 265.8.7 - Release Date: 2/10/2005 ------=_NextPart_000_0189_01C510D3.3116D150 Content-Type: text/html; charset=iso-8859-1 Content-Transfer-Encoding: quoted-printable
 
----- Original Message -----
From:=20 Perry=20 Mick
Sent: Friday, February 11, 2005 = 11:36=20 PM
Subject: [FlyRotary] Vapor = lock

  One final = thought.....my=20 aluminum sump tank in not vented. Seems we discussed this at length = when I was=20 building this thing, and since the overflow is pumped into the sump = tank, the=20 fuel might just be pumped right out of the vent. Take care. Paul=20 Conner

Paul, I think this is your problem. I brought this up on = this=20 list once before. I nearly had the makings of a fatal accident a year = ago when=20 I temporarily had my sump tank unvented. I had been flying for over = four years=20 with a vented sump tank and never had a problem.
I flew to = Puyallup WA for=20 the airfaire early in the morning. The plane sat out in the sun all = day, with=20 temperatures rising. When I went out early afternoon to depart, I = lifted the=20 nose, hopped in, started the engine, taxied to active runway. Very = fortunately=20 there were several planes in the pattern and I had to wait for = takeoff.=20 Finally, I took the active, pushed in full throttle - and the engine = died.=20 This had never happened before. I got out and pushed it off the = runway,=20 somewhat stumped. Finally I remembered the rubber cap I had put on the = sump=20 tank vent. I popped it off and heard a "poof" sound, and then the = sound of=20 fuel flowing into the sump tank. My sump tank is mounted low, fed from = the=20 main tank by gravity. Apparently being parked nose down for several = hours out=20 in the sun allowed vapor lock to form in the lines between the main = tank and=20 the sump tank.  If those planes had not been in the pattern, I = would have=20 taken off from a relatively short field in a congested area and the = engine=20 would have quit right after takeoff with no place to land = safely.

My=20 sump tank vent is up at the top of the fuselage with the main tank = vents, I=20 never have problems with fuel being pumped out the vent. I now = maintain that=20 the sump tank must be vented - to do anything else may be fatal. I've = brought=20 this up before on this list and more recently on Canard=20 Aviators.

Perry
Hi, Perrry....One = question....Does your=20 unburned fuel (from the fuel rail) go back into your sump tank=20 also?   Or do you return the unused fuel to one of your fuel = tanks?  If I were returning fuel to one of the main tanks, I = would think=20 that venting the sump would be appropriate, but since I am sending = fuel undere=20 pressure back into the sump tank, I am concerned that once the sump = tank is=20 full, the additional fuel pumped back into the sump tank would take = the path=20 of least resistance....out the vent instead of back up the fuel line = into the=20 tank?   Thanks for your input.  Paul=20 Conner

No virus found in this incoming message.
Checked by AVG=20 Anti-Virus.
Version: 7.0.300 / Virus Database: 265.8.7 - Release = Date:=20 2/10/2005
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