Return-Path: Received: from imf20aec.mail.bellsouth.net ([205.152.59.68] verified) by logan.com (CommuniGate Pro SMTP 4.3c2) with ESMTP id 758792 for flyrotary@lancaironline.net; Fri, 25 Feb 2005 08:01:42 -0500 Received-SPF: pass receiver=logan.com; client-ip=205.152.59.68; envelope-from=sqpilot@bellsouth.net Received: from [209.214.45.125] by imf20aec.mail.bellsouth.net (InterMail vM.5.01.06.11 201-253-122-130-111-20040605) with ESMTP id <20050225130055.YLRI1995.imf20aec.mail.bellsouth.net@[209.214.45.125]> for ; Fri, 25 Feb 2005 08:00:55 -0500 Received: from 127.0.0.1 (AVG SMTP 7.0.300 [266.4.0]); Fri, 25 Feb 2005 07:00:46 -0600 Message-ID: <00e001c51b3a$048c3dc0$862cd6d1@paul52u7f5qyav> From: "Paul" To: "Rotary motors in aircraft" References: Subject: Re: [FlyRotary] Re: Vapor Lock Date: Fri, 25 Feb 2005 07:00:44 -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-421F217E43F4=======" --=======AVGMAIL-421F217E43F4======= Content-Type: multipart/alternative; boundary="----=_NextPart_000_00DD_01C51B07.B9CDF210" ------=_NextPart_000_00DD_01C51B07.B9CDF210 Content-Type: text/plain; charset=Windows-1252 Content-Transfer-Encoding: quoted-printable Yes, but they only have 22 gallons. I have 70 gallons with two forward = facing vents directed into an airstream that is going 200 mph, not 90 = mph like the Cessna. Seems like I should have more pressure coming into = the vents at the higher airspeeds? Paul Conner ----- Original Message -----=20 From: Finn Lassen=20 To: Rotary motors in aircraft=20 Sent: Thursday, February 24, 2005 10:20 PM Subject: [FlyRotary] Re: Vapor Lock The Cessna 152/172 have, what, 2 - 3 feet of gravity feed, you have = only one. Anyway, here's a question. Is there a possibility that the path from = the lagging tank gets hotter than the faster draining tank? I'm = beginning to think that even a minor temp rise in fuel path to pumps = produces a much bigger effect than any of us would imagine. Just a = theory not proven yet. Finn Jim Sower wrote: This problem drove me NUTS for two years. I tried everything. For = example, I checked the vents as best I could, leveled the airplane = (checked the ball to ensure it was centered - it was), disconnected the = fuel line from the engine side of the firewall and let it drain into a = bucket. I turned off one strake at a time (with manual maintenance = valve) and timed how long it took for the other strake to gravity drain = ten gal of fuel into the sump, out of the sump through the boost pump, = through the filter and then through the firewall into the bucket(s). = Then I turned it off and did the same thing with the left tank. They = both drained 10 gal each within 5% of the same time. Then I = reconnected all the plumbing, taped over the fuel caps so there's no = possible way they could leak and went flying. Right tank drained 20 gal = while the left tank maybe 2 or 3. Level balanced flight on a cross = country. All fuel lines, vent lines, etc. are as identical as I am able = to make them. To this day, I've not met anybody who can explain what = happened. I tried everything. Back and forth on the Velocity list much = longer than you've been inquiring after your vapor lock. NOTHING. I = figured out a workaround - I installed electric shutoff valves in place = of the manual maintenance valves between the strake and the sump. Now, = when one tank doesn't transfer, I turn off the tank that does and let = the "reluctant" tank catch up. The pump sucks it through the system = just fine (the head pressure of 6" of fuel is about 0.16 psi - a problem = that would inhibit that flow you can't even MEASURE. Assymmetric = transfer is common as dirt in the Velocity community (but not nearly as = persistent as mine). It was also a problem a long time with the = Vari-EZ.=20 =20 -------------------------------------------------------------------------= ----- No virus found in this incoming message. Checked by AVG Anti-Virus. Version: 7.0.300 / Virus Database: 266.4.0 - Release Date: 2/22/2005 ------=_NextPart_000_00DD_01C51B07.B9CDF210 Content-Type: text/html; charset=Windows-1252 Content-Transfer-Encoding: quoted-printable
Yes, but they only have 22 gallons. I = have 70=20 gallons with two forward facing vents directed into an airstream that is = going=20 200 mph, not 90 mph like the Cessna. Seems like I should have more = pressure=20 coming into the vents at the higher airspeeds?  Paul = Conner
----- Original Message -----
From:=20 Finn=20 Lassen
Sent: Thursday, February 24, = 2005 10:20=20 PM
Subject: [FlyRotary] Re: Vapor = Lock

The Cessna 152/172 have, what, 2 - 3 feet of gravity = feed, you=20 have only one.

Anyway, here's a question. Is there a = possibility that=20 the path from the lagging tank gets hotter than the faster draining = tank? I'm=20 beginning to think that even a minor temp rise in fuel path to pumps = produces=20 a much bigger effect than any of us would imagine. Just a theory not = proven=20 yet.

Finn

Jim Sower wrote:
This problem drove me NUTS for two years.  I = tried=20 everything.  For example, I checked the vents as best I could, = leveled=20 the airplane (checked the ball to ensure it was centered - it was),=20 disconnected the fuel line from the engine side of the firewall and = let it=20 drain into a bucket.  I turned off one strake at a time (with = manual=20 maintenance valve) and timed how long it took for the other strake = to=20 gravity drain ten gal of fuel into the sump, out of the sump through = the=20 boost pump, through the filter and then through the firewall into = the=20 bucket(s).  Then I turned it off and did the same thing with = the left=20 tank.  They both drained 10 gal each  within 5% of the = same=20 time.  Then I reconnected all the plumbing, taped over the fuel = caps so=20 there's no possible way they could leak and went flying.  Right = tank=20 drained 20 gal while the left tank maybe 2 or 3.  Level = balanced flight=20 on a cross country.  All fuel lines, vent lines, etc. are as = identical=20 as I am able to make them.  To this day, I've not met = anybody=20 who can explain what happened.  I tried = everything.  Back=20 and forth on the Velocity list much longer than you've been = inquiring after=20 your vapor lock.  NOTHING.  I figured out a workaround - I = installed electric shutoff valves in place of the manual maintenance = valves=20 between the strake and the sump.  Now, when one tank doesn't = transfer,=20 I turn off the tank that does and let the "reluctant" tank catch = up. =20 The pump sucks it through the system just fine (the head pressure of = 6" of=20 fuel is about 0.16 psi - a problem that would inhibit that flow you = can't=20 even MEASURE.  Assymmetric transfer is common as dirt in the = Velocity=20 community (but not nearly as persistent as mine).  It was also = a=20 problem a long time with the Vari-EZ. 
  =

No virus found in this incoming message.
Checked by AVG=20 Anti-Virus.
Version: 7.0.300 / Virus Database: 266.4.0 - Release = Date:=20 2/22/2005
------=_NextPart_000_00DD_01C51B07.B9CDF210-- --=======AVGMAIL-421F217E43F4======= Content-Type: text/plain; x-avg=cert; charset=us-ascii Content-Transfer-Encoding: quoted-printable Content-Disposition: inline Content-Description: "AVG certification" No virus found in this outgoing message. Checked by AVG Anti-Virus. Version: 7.0.300 / Virus Database: 266.4.0 - Release Date: 2/22/2005 --=======AVGMAIL-421F217E43F4=======--