X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from poplet2.per.eftel.com ([203.24.100.45] verified) by logan.com (CommuniGate Pro SMTP 5.2.16) with ESMTP id 3866759 for flyrotary@lancaironline.net; Sat, 26 Sep 2009 17:28:38 -0400 Received-SPF: none receiver=logan.com; client-ip=203.24.100.45; envelope-from=lendich@aanet.com.au Received: from sv1-1.aanet.com.au (sv1-1.per.aanet.com.au [203.24.100.68]) by poplet2.per.eftel.com (Postfix) with ESMTP id 288A81737CC for ; Sun, 27 Sep 2009 05:28:02 +0800 (WST) Received: from ownerf1fc517b8 (203.171.92.134.static.rev.aanet.com.au [203.171.92.134]) by sv1-1.aanet.com.au (Postfix) with SMTP id 32D8BBEC031 for ; Sun, 27 Sep 2009 05:28:01 +0800 (WST) Message-ID: <2BCCDCCF829340C780FBB1D56C7CC3B7@ownerf1fc517b8> From: "George Lendich" To: "Rotary motors in aircraft" References: Subject: Re: [FlyRotary] Re: gas smell Date: Sun, 27 Sep 2009 07:28:03 +1000 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_001D_01CA3F44.0C8CF1D0" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2900.5843 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.5579 X-Antivirus: avast! (VPS 090926-0, 09/26/2009), Outbound message X-Antivirus-Status: Clean This is a multi-part message in MIME format. ------=_NextPart_000_001D_01CA3F44.0C8CF1D0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Mike /David, Never use any silicone in fuel tank applications, you will have = residue and the residue will plug your filter lines- don't ask me how I = know. Use/ make nutplates with sealed nuts ( dome nuts or covered nuts - = better still SS long nuts with the ends welded-up ) and the proseal = would be better than RTV. George ( down under) Mike, I have long had a fuel smell in the cockpit and have traced down = several culprits. Each one made improvements, I have finally solved = most of the issues. I know these will not all apply to you, but I am = sure some will. I'll put them in chronological order here, but the ones = in bold most likely apply to you. Luckily, the 2-stroke oil we put in = the gas leaves a telltale residue after it builds up long enough - makes = tracing these leaks much easier. And get in there with that sniffer... -Small leak at AN-flare from left tank to fuel selector. fixed by = re-securing -Small leak at at fitting just downstream of fuel pump. -small leak at fuel pressure sensor NPT fitting. -While running normally aspirated I was getting a strong smell in = flight. Tracked that down to mostly the pax fresh air inlet.=20 This eventually traced to the intake system. Seems that even in full = bore flight, fuel from the secondary injectors (8" from inlets) would = come backwards and mix with cowl air, some of which would seep out the = cowl seam, which was right ahead of the pax fresh air inlet and blowing = right into Anne's face. She kept smelling really strong gas "making her = sick." To me it was not quite that strong and I thought she was over = reacting until I leaned over and smelled the pax air inlet - sure wish I = solved that issue before flying Anne to Vegas. Solved this by = re-installing some of the turbo intake piping to catch any back = migrating fuel. - Very faint smell but quickly accumulating residue (oil would pool in = the recesses on top of the engine) from fuel leaking out through a = welding defect in the intake runners - fixed with JB Weld. It still = also gets out around the axle in the throttle body while running higher = than ambient MAP. I don't know how to fix that one. -There is a small leak in the fuel vent tubing system that runs = through the cockpit, but I have not been able to find the exact location = so I will still smell it a little if I start to vent fuel on a hot day. -This year my port side fuel tank gasket (the cork one) started = leaking quite a bit around the screws that hold the plate in place. = This required removal of the entire fuel tank to get proper access = because I had previously tried unsuccessfully to seal around those = screws with some sort of epoxy putty. When you think about it, there is = no gasket to keep fuel out around those screws. The fuel can get past = the threads of the nut plate, bypass the gasket altogether, and get out = around the head of the screw. 75% of those screws had 2-stroke residue. = Fuel vapor from that wing root area easily gets into the cockpit in = flight through the openings for the aileron pushrods and control column. = I fixed that one by replacing the cork and putting some proseal under = the head of each of the screws - though I wish I had used RTV. That = proseal will be a real beotch if I ever need to get that plate off = again. -I also found a number of very small leaks (residue) past a number of = the rivets on the quick build fuel tanks. In particular, the blind = rivets on the back side just ahead of the spar were prone to leak (about = 6 of those had some amount of 2-stroke residue). I put dabs of proseal = around each offender. I don't know if that fixed it (would need to = remove fuel tank again to check) but the leaks were small enough to not = really be a problem. - On one cross country flight I nearly gassed myself with a dirty rag. = Some pump operator had spilled massive amounts of fuel over each wing. = Actually that happens almost universally whenever I let anyone else "top = it off" as those RV tanks go much faster when near full. Now I always = either do it myself or specify the number of gallons to put in each = tank. Anyway, there were no rags at the pump so I used one of my own = and without thinking I tossed it in back. Passing through 10,000 ft the = smell was so strong I was about to puke before I finally was able to = reach the rag and seal it in the ice chest. Smaller amounts of spilled = gas on a rag make less obvious sources of faint fuel odor. - I bought a nifty little go-ped scooter that fits in the back of the = -6 and is fun to use around airports and for small trips. But on my = last cross country I thought I had developed some new (and strong) fuel = leak until I realized that the tank on the go-ped was probably venting = as I went higher. Hope that helps :-) --=20 David (mostly now free of fuel smell) Leonard Turbo Rotary RV-6 N4VY http://N4VY.RotaryRoster.net http://RotaryRoster.net On Fri, Sep 25, 2009 at 7:48 PM, Mike Wills wrote: This is one of those frustrating little issues. In ground running I = dont notice it, but in flight I smell gasoline in the cockpit. I've run = it on the ground trying to detect leaks and cant find any at all. Anyone = got a suggestion for some sort of a sniffer or telltale I could put at = all the connections that would show evidence of leaking? Mike Wills RV-4 N144MW ------=_NextPart_000_001D_01CA3F44.0C8CF1D0 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
 
 Mike /David,
Never use any silicone in fuel tank=20 applications, you will have residue and the residue will plug your = filter=20 lines- don't ask me how I know.
Use/ make nutplates with = sealed nuts (=20 dome nuts or covered nuts - better still SS long nuts with the ends=20 welded-up ) and the proseal would be better than RTV.
George ( down under)
Mike,
I have long had a fuel smell in the cockpit and have traced = down=20 several culprits.  Each one made improvements, I have finally = solved most=20 of the issues.  I know these will not all apply to you, but I am = sure=20 some will.  I'll put them in chronological order here, but the = ones in=20 bold most likely apply to you.  Luckily, the 2-stroke oil we put = in the=20 gas leaves a telltale residue after it builds up long enough - makes = tracing=20 these leaks much easier.  And get in there with that = sniffer...
 
-Small leak at AN-flare from left tank to fuel selector.  = fixed by=20 re-securing
-Small leak at at fitting just downstream of = fuel pump.
-small leak at fuel pressure sensor NPT fitting.
-While running normally aspirated I was getting = a strong=20 smell in flight.  Tracked that down to mostly the pax fresh air=20 inlet. 
This eventually traced to the intake system.  Seems = that even=20 in full bore flight, fuel from the secondary injectors = (8" from=20 inlets) would come backwards and mix with cowl air, some = of=20 which would seep out the cowl seam, which was right ahead of the pax = fresh air=20 inlet and blowing right into Anne's face.  She kept smelling = really=20 strong gas "making her sick."  To me it was not quite that strong = and I=20 thought she was over reacting until I leaned over and smelled the pax = air=20 inlet - sure wish I solved that issue before flying Anne to = Vegas. =20 Solved this by re-installing some of the turbo intake piping to catch = any back=20 migrating fuel.
- Very faint smell but quickly accumulating residue (oil would = pool in=20 the recesses on top of the engine) from fuel leaking out = through a=20 welding defect in the intake runners - fixed with JB Weld.  It = still also=20 gets out around the axle in the throttle body while running = higher than=20 ambient MAP.  I don't know how to fix that one.
-There is a small leak in the fuel vent=20 tubing system that runs through the cockpit, but I = have not=20 been able to find the exact location so I will still smell it a little = if I=20 start to vent fuel on a hot day.
-This year my port side fuel tank gasket (the = cork one)=20 started leaking quite a bit around the screws that hold the = plate in=20 place.  This required removal of the entire fuel tank to = get=20 proper access because I had previously tried unsuccessfully to seal = around=20 those screws with some sort of epoxy putty.  When you think about = it,=20 there is no gasket to keep fuel out around those screws.  The = fuel can=20 get past the threads of the nut plate, bypass the gasket altogether, = and get=20 out around the head of the screw.  75% of those screws had = 2-stroke=20 residue.  Fuel vapor from that wing root area easily gets into = the=20 cockpit in flight through the openings for the aileron pushrods and = control=20 column.  I fixed that one by replacing the cork and putting some = proseal=20 under the head of each of the screws - though I wish I had used = RTV. =20 That proseal will be a real beotch if I ever need to get that = plate off=20 again.
-I also found a number of very small leaks (residue) past a = number of the=20 rivets on the quick build fuel tanks.  In particular, the = blind=20 rivets on the back side just ahead of the spar were prone to = leak=20 (about 6 of those had some amount of 2-stroke residue).  I = put dabs=20 of proseal around each offender.  I don't know if that fixed it = (would=20 need to remove fuel tank again to check) but the leaks were small = enough to=20 not really be a problem.
- On one cross country flight I nearly gassed myself with a = dirty=20 rag.  Some pump operator had spilled massive = amounts=20 of fuel over each wing.  Actually that happens almost = universally=20 whenever I let anyone else "top it off" as those RV tanks go much = faster when=20 near full.  Now I always either do it myself or specify the = number of=20 gallons to put in each tank.  Anyway, there were no rags at the = pump so I=20 used one of my own and without thinking I tossed it in back.  = Passing=20 through 10,000 ft the smell was so strong I was about to puke before I = finally=20 was able to reach the rag and seal it in the ice chest.  Smaller = amounts=20 of spilled gas on a rag make less obvious sources of faint fuel = odor.
- I bought a nifty little go-ped scooter that fits in the back of = the -6=20 and is fun to use around airports and for small trips.  But on my = last=20 cross country I thought I had developed some new (and = strong) fuel leak=20 until I realized that the tank on the go-ped was probably venting as I = went=20 higher.
 
Hope that helps :-)

--
David (mostly now free of fuel smell) = Leonard

Turbo=20 Rotary RV-6 N4VY
http://N4VY.RotaryRoster.nethttp://RotaryRoster.net

On Fri, Sep 25, 2009 at 7:48 PM, Mike Wills = <rv-4mike@cox.net>=20 wrote:
This is one of those frustrating = little issues.=20 In ground running I dont notice it, but in flight I smell gasoline = in the=20 cockpit. I've run it on the ground trying to detect leaks and cant = find any=20 at all. Anyone got a suggestion for some sort of a sniffer or = telltale I=20 could put at all the connections that would show evidence of=20 leaking?
 
Mike Wills
RV-4=20 N144MW



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