X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from mailout1.pacific.net.au ([61.8.0.84] verified) by logan.com (CommuniGate Pro SMTP 4.3.4) with ESMTP id 1002416 for flyrotary@lancaironline.net; Tue, 14 Jun 2005 22:45:25 -0400 Received-SPF: none receiver=logan.com; client-ip=61.8.0.84; envelope-from=peon@pacific.net.au Received: from mailproxy1.pacific.net.au (mailproxy1.pacific.net.au [61.8.0.86]) by mailout1.pacific.net.au (8.13.4/8.13.4/Debian-1) with ESMTP id j5F2idCt021155 for ; Wed, 15 Jun 2005 12:44:39 +1000 Received: from ar1 (ppp27C5.dyn.pacific.net.au [61.8.39.197]) by mailproxy1.pacific.net.au (8.13.4/8.13.4/Debian-1) with SMTP id j5F2iLMJ026329 for ; Wed, 15 Jun 2005 12:44:32 +1000 Message-ID: <001b01c57152$a9ec9bc0$c527083d@ar1> From: "Leon" To: "Rotary motors in aircraft" References: Subject: Air Locks in EFI lines & Scientific Method was Re: [FlyRotary] Re: Is common sense dead (rant mode on) Date: Wed, 15 Jun 2005 12:32:54 +1000 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0016_01C571A6.5A518950" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2800.1409 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1409 This is a multi-part message in MIME format. ------=_NextPart_000_0016_01C571A6.5A518950 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable MessageHi Guys, A timely word of caution. Just want to chuck in some more addled = thoughts on AIR Locks vs VAPOUR Locks. As I mentioned in another post, = It is almost impossible to get a VAPOUR lock in the pressurised part of = an EFI system (unless you are REALLY silly and run the supply line 1/2" = from your exhaust pipe). Lynn Hanover in his post confirms my notion = that vapour locks normally only occur in the LOW pressure part of the = system, especially when a lift pump is used to "suck" fuel (and = therefore subject it to a partial vacuum), especially when they are = close to a heat source and are not adequately shield/insulated. A properly designed EFI system should have no problem priming the high = pressure EFI pump, because it should ALWAYS have a head of fuel on it. = Either being the lowest point in the system, or at the bottom of a = "Surge", 'Header", or "Make-Up" tank (whatever you want to call it). = However, AIR locks are a different matter. The fuel system must be = designed to allow it to purge any air entrained in the system, either = from initial installation, but most especially if you happen to run the = tank dry, either on purpose, or inadvertently during flight. =20 Case in point - I mentioned that I had experienced AIR lock in EFI = systems before. On one occasion, I wasted several hours and a couple = of hundred dollars of dyno time before the penny dropped. Had I walked = away for a few minutes, sat down and thought about it carefully, the = CAUSE of the problem would have been obvious. But I was too close to = the problem, and also too baffled by my own "BS & Brilliance"(};>) as = well ( no smart comments please ...) It took somebody else, not associated with this particular car (it even = had the dyno operator flummoxed - and Rocky is one seriously sharp = rotary dude) to ask the right questions, eliminate all the "red = herrings", and come up with the correct answer - which was that there = was an air lock between the two fuel rails. =20 Fortunately, after a couple of fruitless hours, Rocky & I eventually = agreed that we needed help (yeah I know what you are thinking ... again, = no smart, comments please ...), so we called in our friendly Motec = dealer. He lobs over, looks at the installation, asks a few pointed = questions, and sees the problem almost immediately. Both Rocky & I = ended up with very sore and very flat foreheads that night - (You know = how you slap your forehead when someone points out the blatently = obvious??) - not to mention very sheepish and embarrassed looks on out = faces. See, the symptom was one rail (front rotor) was running lean. The fuel = system was set up with a 4 barrel TB and to treat each rotor separately = with its own fuel rail, instead of using the normal primary/secondary = injector fuel rail set-up. With the front rotor running lean, the motor = obviously wouldn't make any power. =20 It turned out that the bridging supply line between the two fuel rails = was high on the inner guard, and had been put there as a temporary = measure at the race track when an alloy rotary water pump had to be = changed to an earlier cast iron pump, and which fouled on the existing = fuel rail and supply line. Being the highest point in the system, it = naturally trapped a sizeable air lock, which, due to a combination of = circumstances, could not be purged. =20 The air lock prevent most, but not ALL of the fuel flowing to the front = two injectors. the fact that the hose was a -8 made it all the more = difficult to purge. Simply by re-routing the hose DOWN instead of up, = the air lock cleared, and we got back full power immediately.. =20 Forever the "Doubting Thomas", and to make sure we had indeed correctly = diagnosed the problem, and to demonstrate the cause, I then spliced in = a bleed nipple fitting in the -8 hose at the top of the loop, re-fitted = the fuel line back up over the strut tower (complete with massive air = embolism) where it had previously been, and the power problem magically = re-appeared. We then bled out the air lock via the nipple, and bingo, = the power came back. So simple, yet it escaped two really experienced = rotary mechanics that night. AgHCF (All gods Have Clay Feet). So I just want to exhort you guys to be careful with your diagnosis of = any problems that arise. Think carefully about it, don't jump to = conclusions, ask the right questions, and be prepared to consult = others (which is what this list is about), Often, we can become too = close to a problem and it requires a disinterested party to be able to = see clearly the whole situation. Then try to design tests to prove any = assertions wrong - not right (which is why I fitted the bleed nipple in = the line). =20 See, I just didn't want to really believe that an air lock was actually = the problem - I didn't even KNOW for sure that there WAS an airlock in = the hose, even though common sense told me there was. I had to see it = to believe it (the "Doubting Thomas" Syndrome with which I am so heavily = infected) - sure enough, on opening the bleed nipple, there was a rush = of air before the fuel began to squirt out. QED. =20 The problem was reproducible as well. (As Einstein once said about = insanity (with which I am also infected): "doing the same thing over = and over again and expecting different results"). Cheers, Leon ----- Original Message -----=20 From: al p wick=20 To: Rotary motors in aircraft=20 Sent: Sunday, June 12, 2005 4:39 PM Subject: [FlyRotary] Re: Is common sense dead (rant mode on) On Sat, 11 Jun 2005 21:48:53 -0500 "rijakits" = writes: Everyone here is interested in solutions, SPECIFIC solutions. Specifically, Follow this general principal: When you have a theory, find way to prove it's true. Use facts. ------=_NextPart_000_0016_01C571A6.5A518950 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Message
Hi Guys,
 
A timely word of caution.  Just = want to chuck=20 in some more addled thoughts on AIR Locks vs VAPOUR Locks.  As I = mentioned=20 in another post,  It is almost impossible to get a VAPOUR lock in = the=20 pressurised part of an EFI system (unless you are REALLY silly and = run the=20 supply line 1/2" from your exhaust pipe).  Lynn Hanover in his = post=20 confirms my notion that vapour locks normally only occur in = the LOW=20 pressure part of the system, especially when a lift pump is used to = "suck" fuel=20 (and therefore subject it to a partial vacuum),  especially when = they are=20 close to a heat source and are not adequately = shield/insulated.
 
A properly designed EFI system should = have no=20 problem priming the high pressure EFI pump,  because it should = ALWAYS have=20 a head of fuel on it.  Either being the lowest point in the = system, =20 or at the bottom of a "Surge",  'Header",  or "Make-Up" tank = (whatever=20 you want to call it).  However,  AIR locks are a different=20 matter.  The fuel system must be designed to allow it to purge any = air=20 entrained in the system, either from initial = installation,  but=20 most especially if you happen to run the tank dry,  either on=20 purpose,  or inadvertently during flight. 
 
Case in point - I mentioned that I had = experienced=20 AIR lock in EFI systems before.  On one occasion,  I wasted = several=20 hours and a couple of hundred dollars of dyno time before the penny=20 dropped.  Had I walked away for a few minutes,  sat down and = thought=20 about it carefully,  the CAUSE of the problem would have been=20 obvious.  But I was too close to the problem,  and also=20 too baffled by my own "BS & Brilliance"(};>) as well ( = no smart=20 comments please ...)
 
It took somebody else,  not = associated with=20 this particular car (it even had the dyno operator flummoxed - and = Rocky is=20 one seriously sharp rotary dude) to ask the right questions, =20 eliminate all the "red herrings",  and come up with the correct = answer=20 -  which was that there was an air lock between the two fuel = rails. =20
 
Fortunately,  after a couple of = fruitless=20 hours,  Rocky & I eventually agreed that we needed help (yeah I = know=20 what you are thinking ... again,  no smart, comments please = ...),  so=20 we called in our friendly Motec dealer.  He lobs over,  looks = at the=20 installation,  asks a few pointed questions,  and sees the = problem=20 almost immediately.  Both Rocky & I ended up with very sore and = very flat foreheads that night - (You know how you slap your = forehead when=20 someone points out the blatently obvious??) - not to mention very = sheepish=20 and embarrassed looks on out faces.
 
See,  the symptom was one rail = (front=20 rotor) was running lean.  The fuel system was set up with a 4 = barrel=20 TB and to treat each rotor separately with its own fuel rail,  = instead=20 of using the normal primary/secondary injector fuel rail set-up. = With the=20 front rotor running lean,  the motor obviously wouldn't make = any=20 power. 
 
It turned out that the bridging supply = line between=20 the two fuel rails was high on the inner guard,  and had been put = there as=20 a temporary measure at the race track when an alloy rotary water = pump had=20 to be changed to an earlier cast iron pump,  and which fouled on = the=20 existing fuel rail and supply line.  Being the highest point in the = system,  it naturally trapped a sizeable air lock,  = which,  due=20 to a combination of circumstances,   could not be purged. 
 
The air lock prevent most,  but = not ALL of the=20 fuel flowing to the front two injectors. the fact that the hose was = a -8=20 made it all the more difficult to purge.   Simply by = re-routing the=20 hose DOWN instead of up,  the air lock cleared,  and we got = back full=20 power immediately.. 
 
Forever the "Doubting Thomas",  = and to make=20 sure we had indeed correctly diagnosed the problem,  and to=20 demonstrate the cause,  I then spliced in a bleed nipple = fitting=20 in the -8 hose at the top of the loop,  re-fitted the fuel = line back=20 up over the strut tower (complete with massive air embolism) where=20 it had previously been, and the power problem magically=20 re-appeared.  We then bled out the air lock via the nipple,  = and=20 bingo,  the power came back.  So simple,  yet it escaped = two=20 really experienced rotary mechanics that night.  AgHCF (All gods = Have Clay=20 Feet).
 
So I just want to exhort you guys to be = careful=20 with your diagnosis of any problems that arise.  Think carefully = about=20 it, don't jump to conclusions,  ask the right questions,  = and be=20 prepared to consult others (which is what this list is = about),  =20 Often, we can become too close to a problem and it requires a = disinterested=20 party to be able to see clearly the whole situation.  Then try to = design=20 tests to prove any assertions wrong - not right (which is why I fitted = the bleed=20 nipple in the line). 
 
See,  I just didn't want to really = believe=20 that an air lock was actually the problem - I didn't even KNOW for = sure=20 that there WAS an airlock in the hose,  even though common sense = told me=20 there was.  I had to see it to believe it (the "Doubting Thomas" = Syndrome=20 with which I am so heavily infected) - sure enough,  on opening the = bleed=20 nipple,  there was a rush of air before the fuel began to squirt=20 out.  QED. 
 
The problem was reproducible as well. = (As Einstein once said about insanity (with which = I am also=20 infected):  "doing the same thing over and over again and expecting = different results").
 
 
Cheers,
 
Leon
 
 
----- Original Message -----
From:=20 al p = wick
Sent: Sunday, June 12, 2005 = 4:39 PM
Subject: [FlyRotary] Re: Is = common sense=20 dead (rant mode on)

 
On Sat, 11 Jun 2005 21:48:53 -0500 "rijakits" <rijakits@cwpanama.net>=20 writes:
Everyone here is interested = in solutions,=20 SPECIFIC solutions.
 
 
 
Specifically, Follow this general principal:
When you have a theory, find way to prove it's true. Use facts.=20
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