X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from [216.148.227.118] (HELO rwcrmhc12.comcast.net) by logan.com (CommuniGate Pro SMTP 4.3.6) with ESMTP id 624336 for flyrotary@lancaironline.net; Thu, 04 Aug 2005 00:02:13 -0400 Received-SPF: none receiver=logan.com; client-ip=216.148.227.118; envelope-from=n3773@comcast.net Received: from rv8 (c-24-21-140-241.hsd1.or.comcast.net[24.21.140.241]) by comcast.net (rwcrmhc13) with SMTP id <2005080404011901500j44b1e>; Thu, 4 Aug 2005 04:01:24 +0000 Message-ID: <001301c598a9$2e16d370$f18c1518@rv8> Reply-To: "kevin lane" From: "kevin lane" To: "Rotary motors in aircraft" References: Subject: Re: [FlyRotary] Float Bowl?? - -lycoming O-320 Date: Wed, 3 Aug 2005 21:01:15 -0700 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_000D_01C5986E.7CDB79B0" 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 This is a multi-part message in MIME format. ------=_NextPart_000_000D_01C5986E.7CDB79B0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Ed - my hangar-mate returns from Oshkosh next week. I will swap carbs = with his and see what happens. it would be unusual to have the new carb = mimic problems that the old one did, however, I'm beyond the simple = explanations at this point. your number estimates are very good. it is a shame that I can't run = very long on the ground before overheating. I blocked off my inlets and = attached a leaf blower to my plenum thinking that it could keep the = engine cool enough on the ground. I guess I proved that cooling takes = more than, oh, a 1/10 hp 110V motor puts out, even if that blower can = clean the entire hangar in one blast and claims a 220mph wind. when I = shut the engine off I have to be careful, because I can see a degree a = second cooling with my "turbo cooling" setup. at 800rpm my blower can = only hold the temp even. I wish I could run longer on the ground, say = at 2000rpm and see what happens, but my cht's get too high(215) before = anything happens.(indicating that I am not having valve/push rod/heat = problems?) maybe if I used a garden hose to water cool? :-) you are right in that it seems that I am supplying enough fuel, both = pressure and quantity. the electric pump alone will pump 25 gal/hr. I = am running 3/8" auto rubber hose right now to keep things easy, so I = know I don't have any internal blockages. I guess I'm going to have to = take that new carb apart and check the float level. it is very simple, = using a drill bit as a thickness gauge. removing the carb is not so = much fun. another idea would be to find a O2 sensor and see if my mixture runs = lean as it stumbles. I don't know if a portable unit is made. sensors = might be nice to have added to the exhaust, although I guess I'd need = two since I have dual exhaust. that would answer leaning questions = also.(but, will 1970's technology work on 1930's equipment? :-) meanwhile I have to go vacation in your state with my wife's family, out = on nags head. I wanted to fly my rv out originally, ha! this is the = first real problem I've had in 8 years. a learning experience, right? = that's why we claimed we were building these, I seem to remember. Kevin Lane Portland, OR e-mail-> n3773@comcast.net ----- Original Message -----=20 From: Ed Anderson=20 To: Rotary motors in aircraft=20 Sent: Sunday, July 03, 2005 5:57 PM Subject: [FlyRotary] Float Bowl?? - -lycoming O-320 Kevin, The fact is the engine does run at 2150 rpm for about 2 minutes = before it stumbles. If burning say 12 GPH. Then that is 0.2 = gal/minute (12/60). So you engine apparently burns from 0.2 to 0.4 = gallons before it starts to stumble. It runs at 1500 rpm (you do not = give a fuel flow) - so assuming the fuel flow is linear then at 1500 rpm = your fuel flow is 1500/2150 *12 =3D 8.37 GPH, which is sustainable. Now since your fuel system (what ever the problem ) can sustain 1500 = rpm or 8.37 GPH (0.139 GPM) that is approx 70% of the fuel flow you need = at 2150 rpm. So lets say your carb's flow bowl volume is 1/2 pint. = That is 0.0625 gallon. =20 So consider the flow bowl simply a part of your fuel flow. At 12 GPH = (0.2 gpm), the bowl would empty (or get too low to sustain 2150 rpm) in = .0625/0.2 =3D 0.3125 minutes or 18.75 seconds. So at first glance that = would not seem to be the problem. However - that is provided there were = no fuel flowing into the bowl at all. But of course there is - at least = at the rate of 0.139 gph (8.37 GPH). So the draw down would actually be = the difference between the demand (12 gph) and the supply (8.37 gph). = That turns out to be 12-8.37 =3D 3.36 GPH (or .056 gpm).=20 So taking our 1/2 pint float bowl at 0.0625 gallons and a draw down = rate of .056 gpm we have .0625/.056 =3D 1.11 minutes in which it would = take a full carb fuel bowl to be drawn down to where it could no longer = sustain the 12 gph flow rate. Now that is not quite your 2 minutes, = but getting close to it . So unless I screwed up the math(or my = assumption about your fuel flow at 1500 rpm is off or your float bowl is = not 1/2 pint), your symptoms sure look like a fuel flow problem to me. =20 Based on everthing you checked and found OK, I would start to suspect = the carburator myself. I know nothing about aircraft carburetors, but = assume they have a float which regulates how open a valve is that = regulates flow into the carburator and therefore can determine the max = rate at which the flow bowl will fill. Its possible that the there is = something wrong in that area (since your check appears to have = eliminated everything else in the fuel system as a possible cause).=20 Also, I would disconnect the fuel feed to the carb stick it into a = container and run the pump (electric in this case) for one minute and = the measure and calculate the max fuel flow your system gives you. This = won't prove anything is wrong with the carb but will at least show you = are getting more than 8.7 gph fuel flow to the carb. If you are not = getting at least 18-20 GPH fuel flow I think you have something in your = system that needs fixing. =20 About all I can think of. Ed A ----- Original Message -----=20 From: kevin lane=20 To: Rotary motors in aircraft=20 Sent: Wednesday, August 03, 2005 7:15 PM Subject: [FlyRotary] further testing - -lycoming O-320 my engine continues to baffle me and everyone else on the airport. = I would send it to a mechanic, but I've spoken with all of them and they = have no ideas either. it continues to look like fuel starvation, but no = gauges support this theory. it runs at 2150rpm, burning 11.5-12.3 gals = per hr, 3 lbs fuel pressure, for about 2 minutes then stumbles(and will = die unless I reduce the throttle to 1500rpm. )the stumbling occurs = when cht's are hitting 375 - 410. continued running at 1500 allows the = cht's to climb, so I have to shut things down. the same behavior = occurred when I flew the plane the first two times (until I realized I = could duplicate the problem on the ground) I have a new carb(ma4spa) = and 4 rebuilt cyls (on which I am attempting to set the rings, = unfortunately) if I run the engine at less than full rich the engine = won't stumble before temps hit 400+ and I have to pull power. I bypassed my fuel filters with no difference. I installed new = filters that have a core of little brass balls stuck together and = seemingly much better flow than the other filter(no angles either, just = straight flow) I cleaned and backflushed the fuel pickups and vents, ran with the = gas caps off(no diff). my fuel flow is not changing(until it sputters = back to 1500rpm), so my idea that the carb bowl was slowly not being = refilled doesn't show up. the same problem existed before I had the = cyls rebuilt and welded, so I doubt that stuck valves/weak springs are = to blame. also, that would show problems from the start, not a few = minutes later. everyone wants to blame the electronic ig. switching between mag = and elec. during the first minute shows no diff. switching after it = starts to falter shows no diff. pulling back to 1500rpm after falter = shows no diff. I can't believe I have a spark or timing problem because = there are no times when one works and the other doesn't. my slick mag = is brand new also. I haven't tried new plugs yet, the current ones are = new, although I've heard many stories of bad new plugs (hey, what do you = want for $20?) my 1" dia. cheapy van's fuel pressure meter is now showing 3 lbs. I = removed the pressure regulator. in the past it used to show 8lbs = pressure (hence I installed the regulator)and my carb showed signs of = leakage which is one reason I replaced it. I have no idea why it shows = only 3 lbs now. I tried plumbing the carb directly from a gas can. I = forgot to switch the fuel line off and shot fuel clear out on the wing = when the engine started. I would guess that the mech. fuel pump is = working correctly. the facet elec pump will pump about 1 gallon in 2 = minutes when pumping into a gas can thru the mechanical pump. it makes = no diff. if I run the facet or not. I have bypassed the mech. pump and = run just with the facet, no diff., in fact, when I shut off the facet = the engine still runs until the bowl burns down, maybe 30 sec.? it is hard to believe that both the auto plugs and aero plugs are = simultaneously failing due to heat. I could fly the plane at less than = full rich to see how long it would fly I suppose, but that seems = unnecessarily risky. I've had two "lucky" flights so far. I checked for induction leaks(pressurized and soap solution) and = found nothing. I am out of ideas. this problem is just kicking my butt. = hopefully one of you guys will spark an new idea or theory for me. Kevin Lane Portland, OR e-mail-> n3773@comcast.net ------=_NextPart_000_000D_01C5986E.7CDB79B0 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
Ed - my hangar-mate returns = from Oshkosh=20 next week.  I will swap carbs with his and see what happens.  = it would=20 be unusual to have the new carb mimic problems that the old one did, = however,=20 I'm beyond the simple explanations at this point.
your number estimates are = very=20 good.  it is a shame that I can't run very long on the ground = before=20 overheating.  I blocked off my inlets and attached a leaf blower to = my=20 plenum thinking that it could keep the engine cool enough on the = ground.  I=20 guess I proved that cooling takes more than, oh, a 1/10 hp 110V motor = puts out,=20 even if that blower can clean the entire hangar in one blast and claims = a 220mph=20 wind.  when I shut the engine off I have to be careful, because I = can see a=20 degree a second cooling with my "turbo cooling" setup.  at 800rpm = my blower=20 can only hold the temp even.  I wish I could run longer on the = ground, say=20 at 2000rpm and see what happens, but my cht's get too high(215) before = anything=20 happens.(indicating that I am not having valve/push rod/heat problems?) = maybe if=20 I used a garden hose to water cool?  :-)
you are right in that it = seems that I am=20 supplying enough fuel, both pressure and quantity.  the electric = pump alone=20 will pump 25 gal/hr.  I am running 3/8" auto rubber hose right now = to keep=20 things easy, so I know I don't have any internal blockages.  =  I guess=20 I'm going to have to take that new carb apart and check the float = level. =20 it is very simple, using a drill bit as a thickness gauge.  = removing the=20 carb is not so much fun.
another idea would be to find = a O2 sensor=20 and see if my mixture runs lean as it stumbles.  I don't know if a = portable=20 unit is made.  sensors might be nice to have added to the exhaust, = although=20 I guess I'd need two since I have dual exhaust.  that would answer = leaning=20 questions also.(but, will 1970's technology work on 1930's equipment?=20 :-)
meanwhile I have to go = vacation in your=20 state with my wife's family, out on nags head.  I wanted to fly my = rv out=20 originally, ha!  this is the first real problem I've had in 8 = years. =20 a learning experience, right?  that's why we claimed we were = building=20 these, I seem to remember.
Kevin Lane  Portland, OR
e-mail-> n3773@comcast.net
----- Original Message -----
From:=20 Ed=20 Anderson
Sent: Sunday, July 03, 2005 = 5:57 PM
Subject: [FlyRotary] Float = Bowl?? -=20 -lycoming O-320

Kevin,
 
The fact is  the engine does run at = 2150 rpm=20 for about 2 minutes before it stumbles.   If burning say 12=20 GPH.  Then that is 0.2 gal/minute (12/60).  So you engine = apparently=20 burns from 0.2 to 0.4 gallons before it starts to = stumble.   =20 It runs at 1500 rpm (you do not give a fuel flow) - = so assuming the=20 fuel flow is linear then at 1500 rpm your fuel flow is 1500/2150 *12 = =3D 8.37=20 GPH, which is sustainable.
 
Now since your fuel system (what ever the = problem ) can=20 sustain 1500 rpm or 8.37 GPH (0.139 GPM) that is approx 70% of the = fuel flow=20 you need at 2150 rpm.  So lets say your carb's flow bowl volume = is 1/2=20 pint.  That is 0.0625 gallon. 
 
So consider the flow bowl simply a part of = your fuel=20 flow.  At 12 GPH (0.2 gpm), the bowl would empty (or get too low = to=20 sustain 2150 rpm) in .0625/0.2 =3D 0.3125 minutes or 18.75 = seconds.  So at=20 first glance that would not seem to be the problem.  = However -=20 that is provided there were no fuel flowing into the bowl at = all.  But of=20 course there is - at least at the rate of 0.139 gph (8.37 GPH).  = So the=20 draw down would actually be the difference between the demand (12 gph) = and the=20 supply (8.37 gph).  That turns out to be 12-8.37 =3D 3.36 GPH (or = .056=20 gpm).
 
So taking our 1/2 pint float bowl at 0.0625 = gallons and=20 a draw down rate of .056 gpm we have  .0625/.056 =3D 1.11 = minutes in=20 which it would take a full carb fuel bowl to be drawn down to where it = could=20 no longer sustain  the 12 gph flow rate.  Now that is not = quite your=20 2 minutes, but getting close to it .  So unless I screwed up the = math(or=20 my assumption about your fuel flow at 1500 rpm is off or your float = bowl is=20 not 1/2 pint), your symptoms sure look like a fuel flow problem to = me. =20
 
Based on everthing you checked and found OK, I = would=20 start to suspect the carburator myself.  I know nothing about = aircraft=20 carburetors, but assume they have a float which regulates how open a = valve is=20 that regulates flow into the carburator and therefore can determine = the max=20 rate at which the flow bowl will fill. Its possible that the there is=20 something wrong in that area (since your check appears to have = eliminated=20 everything else in the fuel system as a possible cause).
 
Also, I would disconnect the fuel feed to the = carb stick=20 it into a container and run the pump (electric in this case) for one = minute=20 and the measure and calculate the max fuel flow your system gives = you. =20 This won't prove anything is wrong with the carb but will at least = show you=20 are getting more than 8.7 gph fuel flow to the carb.  If you are = not=20 getting at least 18-20 GPH fuel flow I think you have something  = in your=20 system that needs fixing. 
 
About all I can think of.
 
Ed A
 
 ----- Original Message ----- =
From:=20 kevin = lane=20
To: Rotary motors in = aircraft=20
Sent: Wednesday, August 03, = 2005 7:15=20 PM
Subject: [FlyRotary] further = testing -=20 -lycoming O-320

my engine continues to = baffle me and=20 everyone else on the airport.  I would send it to a mechanic, = but I've=20 spoken with all of them and they have no ideas either.  it = continues to=20 look like fuel starvation, but no gauges support this theory.  = it runs=20 at 2150rpm, burning 11.5-12.3 gals per hr, 3 lbs fuel pressure, for = about 2=20 minutes then stumbles(and will die unless I reduce the throttle to=20 1500rpm.  )the stumbling  occurs when cht's are hitting = 375 -=20 410.  continued running at 1500 allows the cht's to climb, so I = have to=20 shut things down.  the same behavior occurred when I flew the = plane the=20 first two times (until I realized I could duplicate the problem on = the=20 ground)  I have a new carb(ma4spa) and 4 rebuilt cyls (on which = I am=20 attempting to set the rings, unfortunately)  if I run the = engine at=20 less than full rich the engine won't stumble before temps hit 400+ = and I=20 have to pull power.
I bypassed my fuel = filters with no=20 difference.  I installed new filters that have a core of little = brass=20 balls stuck together and seemingly much better flow than the = other=20 filter(no angles either, just straight flow)
I cleaned and backflushed = the fuel=20 pickups and vents, ran with the gas caps off(no diff).  my fuel = flow is=20 not changing(until it sputters back to 1500rpm), so my idea that the = carb=20 bowl was slowly not being refilled doesn't show up.  the same = problem=20 existed before I had the cyls rebuilt and welded, so I doubt that = stuck=20 valves/weak springs are to blame.  also, that would show = problems=20 from the start, not a few minutes later.
everyone wants to blame = the=20 electronic ig.  switching between mag and elec.  during = the first=20 minute shows no diff.  switching after it starts to falter = shows no=20 diff.  pulling back to 1500rpm after falter shows no = diff.  I=20 can't believe I have a spark or timing problem because there are no = times=20 when one works and the other doesn't.  my slick mag is brand = new=20 also.  I haven't tried new plugs yet, the current ones are new, = although I've heard many stories of bad new plugs (hey, what do you = want for=20 $20?)
my 1" dia. cheapy van's = fuel pressure=20 meter is now showing 3 lbs.  I removed the pressure = regulator.  in=20 the past it used to show 8lbs pressure (hence I installed the = regulator)and=20 my carb showed signs of leakage which is one reason I replaced = it.  I=20 have no idea why it shows only 3 lbs now.  I tried plumbing the = carb=20 directly from a gas can.  I forgot to switch the fuel line off = and shot=20 fuel clear out on the wing when the engine started.  I would = guess that=20 the mech. fuel pump is working correctly.  the facet elec pump = will=20 pump about 1 gallon in 2 minutes when pumping into a gas can thru = the=20 mechanical pump.  it makes no diff. if I run the facet or = not.  I=20 have bypassed the mech. pump and run just with the facet, no diff., = in fact,=20 when I shut off the facet the engine still runs until the bowl burns = down,=20 maybe 30 sec.?
it is hard to believe = that both the=20 auto plugs and aero plugs are simultaneously failing due to = heat.  I=20 could fly the plane at less than full rich to see how long it would = fly I=20 suppose, but that seems unnecessarily risky.  I've had two = "lucky"=20 flights so far.
I checked for induction=20 leaks(pressurized and soap solution) and found = nothing.
    I am = out of=20 ideas.  this problem is just kicking my butt.  hopefully = one of=20 you guys will spark an new idea or theory for me.
Kevin Lane  Portland, OR
e-mail-> n3773@comcast.net
 
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