X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from outbound-mail.dca.untd.com ([64.136.47.15] verified) by logan.com (CommuniGate Pro SMTP 5.4.1) with SMTP id 5096431 for flyrotary@lancaironline.net; Thu, 18 Aug 2011 13:16:04 -0400 Received-SPF: pass receiver=logan.com; client-ip=64.136.47.15; envelope-from=alwick@juno.com DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=juno.com; s=alpha; t=1313687729; bh=47DEQpj8HBSa+/TImW+5JCeuQeRkm5NMpJWZG3hSuFU=; l=0; h=Message-ID:From:To:Subject:Date:Content-Type; b=skM/yOSBJFMwZ5NH5zVJ3D1VFOq100QjYr2dNvh0zAINcV2mEvMdxMOJtsjvPAUex 3oO8AamYhY9vFlI+QSgeJd2L8O5WbDBRFlFrltxCCZ0szAo6LRVrSXjiu2TgRI8tVd lhEL7ov5Lr0/0X6e2T8yuF/P4GcfLLRH0JMdJRG4= Received: from Penny (50-39-167-113.bvtn.or.frontiernet.net [50.39.167.113]) by smtpout05.dca.untd.com with SMTP id AABHE4UE9AWQU532 for (sender ); Thu, 18 Aug 2011 10:15:11 -0700 (PDT) Message-ID: <3B0C83B1116F4AEDBC10C6EE77CFCA55@Penny> From: "Al Wick" To: "Rotary motors in aircraft" References: In-Reply-To: Subject: Re: [FlyRotary] Dennis Haverlah Fuel System...or any others, for that matter. Date: Thu, 18 Aug 2011 10:15:09 -0700 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_01AC_01CC5D8F.B597E940" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Windows Mail 6.0.6002.18197 X-MimeOLE: Produced By Microsoft MimeOLE V6.0.6002.18463 X-UNTD-BodySize: 33430 X-ContentStamp: 81:40:3298432956 X-MAIL-INFO: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 ef076b3faf2a638f02cf9f7ef73ad363cadbd36abfaa5b93b3b73a6b X-UNTD-OriginStamp: L941HVjjYzDhN3itp//mkCdf0KA+V0gYYb8L2I/QMBbpUlufBj1kCA== X-UNTD-Peer-Info: 10.171.42.35|smtpout05.dca.untd.com|smtpout05.dca.untd.com|alwick@juno.com This is a multi-part message in MIME format. ------=_NextPart_000_01AC_01CC5D8F.B597E940 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable < Mark's problem can best be described as an "Air To: Rotary motors in aircraft Sent: Wednesday, August 17, 2011 1:46 PM Subject: [FlyRotary] Re: Dennis Haverlah Fuel System...or any others, = for that matter. Al,=20 You wrote,"You also test it without the bleed line?"=20 Yes, the test led to the search for a solution. You can see the = "bypass circuit" on Egg's fuel system schematic at = http://www.eggenfellneraircraft.com/Manual-Updates/EarlyManualFuel.html. = This is what I incorporated into my fuel system, and it solved the = problem. Its been quite a few years now, but I may still have some of = the posts on the Eggenfellner list that occurred in search for this as = the final solution. =20 You wrote,"FWIW, everything you describe is not vapor lock, has = nothing to do with vapor lock." =20 As I said, I'm not sure if my condition fits the definition of "vapor = lock", but that's what someone labeled it, and it stuck. The problem is = that EFI pumps don't draw or push air very well. So, if the flowing = fuel is replaced by air due to an empty tank, the pump keeps running, = but essentially stops pumping fuel. With a 40# spring in the downstream = circuit, it is virtually impossible for the pump to pass the air even = though the selector valve has been swiched to the full tank. I would = agree that the fuel injectors should be able to pass the air, provided = the prop is still turning. (This was not the case with my ground test.) = The bypass circuit ensures that flow will be restored as soon as the = bubble passes through the pump and the fuel pump regains its prime. =20 Mark S. On Wed, Aug 17, 2011 at 12:06 PM, Al Wick wrote: wrote: Al Wick wrote: I'm really concerned for some of these fuel designs. The fuel = bleed has nothing to do with vapor lock. Virtually no effect at all. =20 I don't know why others are doing it, but for me, the bleed has = nothing at all to do with vapor lock. Some conversations have been = mixed together, so I can see how that could be the impression. The = point of the pressure bleed is to bleed off the pressure after shutdown. I have a strong, positive head pressure going into my pumps. = They, and the regulator, are about 8" directly below the tank. Excess = fuel goes back to the opposite side of the tank from the pickup, and a = single line goes forward to feed the injectors. The fuel lines are = arranged such that heat soaking the lines to the point of boiling the = gas will push liquid fuel down hill and behind the firewall, isolating = the gaseous gas with its heat at the top of the line. Turning the pumps = on will pressurize the line to 55psi, returning most of the gaseous fuel = back to a liquid state. The ECM is programmed for a longer clearing = pulse on hot start. The point of the bleed is to allow fuel to move back to the = tank. I had the issue of a the pressurized lines being perfectly = sealed. The pressurized fuel was finding the path of least resistance = out, which just happened to be out the injector and into the intake = manifold where it sat as a little puddle. Heat soaking the lines would = not push liquid fuel downhill and back behind the firewall. It would = push more fuel into the manifold. A puddle of gas sitting in a = composite manifold, just above a hot exhaust stack is just bad mojo. A = poorly sealed regulator allows the pressure to bleed off in about 5 = seconds (give or take), isolating the hot fuel in front of the firewall, = and keeping the rest cool and out of the intake manifold. Got nuthin' to do with vapor lock. -- Homepage: http://www.flyrotary.com/ Archive and UnSub: = http://mail.lancaironline.net:81/lists/flyrotary/List.html -- Homepage: http://www.flyrotary.com/ Archive and UnSub: = http://mail.lancaironline.net:81/lists/flyrotary/List.html ------=_NextPart_000_01AC_01CC5D8F.B597E940 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
< Mark's problem can best be = described as=20 an "Air
<Lock" in the = pressure=20 line
 
I'd describe it = as not having=20 "wet fuel inlet". When you turn that fuel valve "on" the first = time, if=20 inlet gets wet, you've nailed an important design characteristic. =
You can simulate = this with=20 clear hose and water. Seal off one end of hose. No air leaks allowed. = Then pour=20 water in other end. If water makes it to closed end, you've got a good = design.=20 It's that simple.
You'll notice = that small diam=20 hose doesn't behave the same. What happens when I add filter to the = hose? What=20 if I put a loop in the line? You are asking the air at capped end to = displace.=20 The air has to be able to move toward open end of tube. Play with it, = pretty=20 interesting.
 
If your plumbing = is already=20 done, you can tape clear hose to plumbing and do the test with water.=20
 
All you are doing = is=20 converting theory to facts. Important concept.
 
-al = wick
 
 
----- Original=20 Message -----
From:=20 Kelly = Troyer
Sent: Wednesday, August 17, = 2011 12:40=20 PM
Subject: [FlyRotary] Dennis = Haverlah Fuel=20 System...or any others, for that matter.

Al , Mark , = Ernest and=20 All,
 
  Perhaps = a name=20 change for the problem is in order.............Instead of = an
actual "Fuel = Vapor Lock"=20 Mark's problem can best be described as an "Air
Lock" in the = pressure=20 line (Or Air Entrapment Lock)..........Ernest's = problem
of injectors = that leak down=20 fuel (into the manifold or the engine with potential
flooding or the = fire hazard=20 of dripping fuel in the cowl) has the same solution
(bypass orifice) either external or = internal=20 to the regulator.......Both=20 problems
no matter what = you call=20 them can be cured with the same solution.............
 
   =  Al as=20 for the leaky injectors it would be great if these things did not=20 wear
over time but = they do=20 eventually become unable to hold pressure and will
exhibit leak-down at some = rate........Unfortunately the Rotary = engine is=20 much
more prone to = flooding and=20 hard starting if this fuel ends up in the Rotor
chamber..........If the=20 primary injectors are left in their stock positions and = are
leaky this is a = direct=20 route to the Rotor............The secondary injectors may
or may not be a = problem=20 depending position and/or manifold design...........
   =
    The=20 bottom line is both potential=20 problems can be averted with a simple
bypass orifice.............As for = an actual=20 "Fuel Vapor Lock" as you say this is
a different = problem and can=20 be addressed by careful attention to fuel pump
positioning = (external or=20 in-tank) ,supply tube (or = hose) size,=20 low restriction
filters to pump = inlet, heat=20 shielding if appropriate,=20 etc................IMHO 
 
Kelly Troyer
"DYKE DELTA = JD2" (Eventually)
"13B ROTARY"_ Engine
"RWS"_RD1C/EC2/EM2
"MISTRAL"_Backplate/Oil = Manifold
"TURBONETICS"_TO4E50 Turbo

From: Mark Steitle = <msteitle@gmail.com>
To: Rotary motors in aircraft=20 <flyrotary@lancaironline.net>
Sent: Wednesday, August 17, = 2011 1:46=20 PM
Subject: = [FlyRotary] Re:=20 Dennis Haverlah Fuel=20 System...or any others, for that matter.

Al,
 
You wrote,"You also test it without the bleed=20 line?" 
 
Yes, the test led to the search for a solution.  You can see = the=20 "bypass circuit" on Egg's fuel system schematic at http://www.eggenfellneraircraft.com/Manual-Updates/EarlyM= anualFuel.html. =20 This is what I incorporated into my fuel system, and it = solved=20 the problem.  Its been quite a few years now, but I may = still=20 have some of the posts on the Eggenfellner list that = occurred in=20 search for this as the final solution.
 
You = wrote,"FWIW, everything = you=20 describe is not vapor lock, has nothing to do with vapor lock." =20
 
As I said, I'm not sure if my condition fits the definition of = "vapor=20 lock", but that's what someone labeled it, and it stuck.  The = problem is=20 that EFI = pumps=20 don't draw or push air very well.  So, if the flowing fuel = is=20 replaced by air due to an empty tank, the pump keeps running, but=20 essentially stops pumping fuel.  With a 40# spring in the = downstream=20 circuit, it is virtually impossible for the pump to pass the = air even=20 though the selector valve has been swiched to the full tank.  I would = agree=20 that the fuel injectors should be able to pass the air, provided the = prop is=20 still turning.  (This was not the case with my ground test.) The = bypass=20 circuit ensures that flow will be restored as soon as the=20 bubble passes through the pump and the fuel pump regains its = prime. 
 
Mark S.

On Wed, Aug 17, 2011 at 12:06 PM, = Al Wick=20 <alwick@juno.com> = wrote:
<I would think that a well-designed fuel system with the = pumps=20 located as low as possible
 
Instead of speculations, you can = actually=20 measure how good it is. A pump, clear fuel lines, and water instead = of fuel.=20 Pinch fuel line with pliers to increase pressure drop.  Watch = bubbles=20 come out of solution. Hear the rattle from pump due to it's = inability to=20 flow air.
If you also put a pressure gage on = pump inlet,=20 you can see how fine fuel filter increases risk. You can see how = small=20 diameter tubing increases risk, heat, head pressure, etc etc. =
 
<the result of a forced landing
Egg had one forced landing. It was caused by vapor lock. = Absolutely=20 NOTHING to do with the lack of bleed line. A day later, Jan made it = to the=20 crash site. Pump would not flow fuel until he cracked the line = loose. This=20 is simply because the inlet to pumps was not wet. He did not = understand=20 this. He just reacted to symptoms. Nothing to do with vapor lock. = Remember,=20 this was crash site. Who knows what attitude plane was at. As I = described,=20 if you screwed up your plumbing from tank to pump, then pump is not = self=20 priming.
 
<tested this system on the ground and it works as advertized
You also test it without the bleed line?
 
FWIW, everything you describe is not = vapor=20 lock, has nothing to do with vapor lock.
 
-al wick
 
----- Original Message ----- =
From: = Mark Steitle =
To: Rotary motors in = aircraft=20
Sent: Wednesday, August 17, = 2011 9:19=20 AM
Subject: [FlyRotary] Re: = Dennis Haverlah = Fuel=20 System...or any others, for that matter.

Al,
 
I would think that a well-designed fuel system with = the=20 pumps located as low as possible, in a cool = area, and a=20 return system should not be troubled with vapor=20 locking.  Although I guess it could happen in Death = Valley=20 in August if the a/c is left out in the sun for 8 hours, and = running=20 auto gas.  So far, I haven't had any problem here in Texas = (temps=20 105* today).   
 
My purpose for installing the bypass circuit was more = critical to=20 safe flight.  (The solution was the result of a forced = landing,=20 or two, in an Eggenfellner Subaru = installation.) =20 During ground runs, using a 5-gallon can, I found that the efi fuel = pumps could not=20 restore pressure once the tank had been allowed to run=20 dry.  When this occurred, the EFI pump would suck a big slug = of air=20 into the inlet side of the pump, loose pressure, and being = unable to=20 build psi equal to the pressure regulator setting, it would stop = pumping=20 fuel (vapor lock).  The only way to restore operation was to = crack=20 open the system downstream of the pump until the slug of air could = be=20 passed on through the fuel pump.  Not sure this meets = your definiton of = "vapor=20 lock", but I think it does, but for a different reason than fuel = vapor=20 pressure.
 
I have tested this system on the ground and it works as advertized.  If the=20 tank runs dry, switched to a full tank, the efi pump will restore pressure to = the system=20 within a few seconds.  I urge all builders to run this test = on their=20 fuel system to determine whether or not their pumps are able to = restore=20 pressure after running a tank dry.  Or, just don't ever run a = tank=20 dry.
 
Mark S.


 
On Wed, Aug 17, 2011 at 10:22 = AM,=20 Ernest Christley=20 <echristley@att.net>=20 wrote:
Al Wick wrote:
I'm really concerned for some of = these=20 fuel designs. The fuel bleed has nothing to do with vapor = lock.=20 Virtually no effect at = all.
 

I don't=20 know why others are doing it, but for me, the bleed has nothing = at all=20 to do with vapor lock.  Some conversations have been mixed=20 together, so I can see how that could be the impression. =  The point=20 of the pressure bleed is to bleed off the pressure after=20 shutdown.

I have a strong, positive head pressure going = into my=20 pumps.  They, and the regulator, are about 8" directly = below the=20 tank.  Excess fuel goes back to the opposite side of the = tank from=20 the pickup, and a single line goes forward to feed the = injectors.=20  The fuel lines are arranged such that heat soaking the = lines to=20 the point of boiling the gas will push liquid fuel down hill and = behind=20 the firewall, isolating the gaseous gas with its heat at the top = of the=20 line.  Turning the pumps on will pressurize the line to = 55psi,=20 returning most of the gaseous fuel back to a liquid state. =  The=20 ECM = is=20 programmed for a longer clearing pulse on hot start.

The = point of=20 the bleed is to allow fuel to move back to the tank.  I had = the=20 issue of a the pressurized lines being perfectly sealed. =  The=20 pressurized fuel was finding the path of least resistance out, = which=20 just happened to be out the injector and into the intake = manifold where=20 it sat as a little puddle.  Heat soaking the lines would = not push=20 liquid fuel downhill and back behind the firewall.  It = would push=20 more fuel into the manifold.  A puddle of gas sitting in a=20 composite manifold, just above a hot exhaust stack is just bad = mojo. =  A poorly=20 sealed regulator allows the pressure to bleed off in about 5 = seconds=20 (give or take), isolating the hot fuel in front of the firewall, = and=20 keeping the rest cool and out of the intake manifold.

Got = nuthin' to = do with=20 vapor lock.

--
Homepage: =  http://www.flyrotary.com/
Archive and = UnSub: =   http://mail.lancaironline.net:81/lists/flyrotary/L= ist.html

=


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Homepage:=  =20 http://www.flyrotary.com/
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