Return-Path: Sender: (Marvin Kaye) To: flyrotary Date: Wed, 08 Oct 2003 21:28:14 -0400 Message-ID: X-Original-Return-Path: Received: from [24.93.67.82] (HELO ms-smtp-01-eri0.southeast.rr.com) by logan.com (CommuniGate Pro SMTP 4.1.5) with ESMTP id 2629309 for flyrotary@lancaironline.net; Wed, 08 Oct 2003 20:48:58 -0400 Received: from o7y6b5 (clt78-020.carolina.rr.com [24.93.78.20]) by ms-smtp-01-eri0.southeast.rr.com (8.12.10/8.12.7) with SMTP id h990mtLe000886 for ; Wed, 8 Oct 2003 20:48:56 -0400 (EDT) X-Original-Message-ID: <001e01c38dfe$ccc0c1a0$1702a8c0@WorkGroup> From: "Ed Anderson" X-Original-To: "flyrotary" Subject: Gear Box Problem and NO SERFI X-Original-Date: Wed, 8 Oct 2003 20:46:38 -0400 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_001B_01C38DDD.456BFE20" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2800.1106 X-MIMEOLE: Produced By Microsoft MimeOLE V6.00.2800.1106 This is a multi-part message in MIME format. ------=_NextPart_000_001B_01C38DDD.456BFE20 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable As most of you know, I had planned on attending the South East Regional = Fly in at Evergreen, Al this past weekend. Well, as some of you = suspect, I didn't make it. I had not mentioned anything before this = point as a gearbox problem developed and I wanted to give Tracy the = change to inspect it before all the spectulation got started on a = possible cause. I have approx 30 hours on the gear box at this point. First, the problem was in the gearbox, BUT IT HAD NOTHING TO DO WITH = TRACY CROOKS EXCELLENT and WELL DESIGNED GEAR BOX!!! I will repeat = that - the problem had nothing whatsoever to do with the gearbox design = (or components or parts or assembly) - I am waiting for the drive to get = shipped back so I can put it on the aircraft and fly to the Shady Bend = flyin later this month. Now with that preamble out of the way. Here is = the story: Well, as I was doing my preflight before my planned departure for SERFI = last Friday morning, I noticed that the engine was a bit harder than = normal to turnover by pulling the prop through (something I always do as = part of the preflight). But, it was a cold 39F morning, so I initially = just attributed the difficulty to that 50 weight oil being sluggish. = However, ANYTHING that is not as it normally is, gets my suspicions = aroused. That gut feeling has saved me more than once and I have = learned to listen to it. =20 I attempted to crank and immediately noticed that not only was it much = slower than normally, but what really got my attention was the battery = voltage dropping to 4-6 volts! That was an immediate clue that plenty = of starter current was flowing but it wasn't turning the engine as it = should. So I immediately stopped cranking and sat there trying to think = the problem through. Got out and play with the prop some more. It was = plain hard to turn - not just sluggish oil. I though initially it might be the engine bearings, but once I noticed = that the normal 1/2" of free play at the tip of the prop was gone = (actually, it was there - just very hard to move) I suspected the gear = box. Well, took off the gear box and the engine turned over fine so it = wasn't an engine problem, but I couldn't budge the prop flange. So = rather than destroy any forensic evidence by taking it apart myself, I = sent it back to Tracy. He just sent me an email detailing the cause. It appears that some = nickel plating (some of you may not be aware- but, I had the aluminum = casing of the gear box nickle coated for protection) had gotten = deposited on the inside of the bronze pressure bearing on the end the = gearbox nearest the prop. For whatever reason, the Nickle accidently = deposited on the bronze bearing by the plating process started flaking = off and some got deposited and smeared onto the inner surface of bronze = oil pressure bearing. Most of the flakes apparently pass through the = gear box without effect. However, the tolerance on the pressure bearing = for the prop shaft is pretty small .0015-.002. In any case, enough of = the nickel plating had gotten smeared on the bronze bearing surface to = reduce the tolerance to .0005 inch. That was what was causing the = binding.=20 I had inspected the components after I had them plated, but apparently = failed to notice a bit on the prop end of the oil pressure bearing, the = plated nickle has a sort of gold tent to it which makes it blend with = the bronze pretty well (at least to my eyeball). In any case, as I = stated earlier, nothing to do with the gearbox per se, just my failure = to detect and remove the nickle plating where it did not belong. I = really appreciate Tracy taking the time to inspect and fix the problem = just before his departure for Copperstate - what a gent! Tracy, said that because I caught it so soon, there was no damage to the = shaft at all and only a very small groove in the bronze. He bored the = bronze bearing sufficient to remove any nickel plating and the small = groove and will be shipping it back this week. So it looks like I will = get to fly to Shady Bend after all. Was not looking forward to the = drive. So now you know the story. I had not mentioned the gearbox problem, = because I did not think it useful to do so until Tracy had a chance to = determine what the problem was. Clearly neither one of us wanted to = think of a design problem (particularly Tracy-I imagine) and fortunately = it was not. I had not even considered a possible design problem as I = knew that Tracy had over 400 hours on his and many others were flying = out there. It Just another one of those strange happenings I seem to = attract {:>) perhaps because I try different things - sort of like Rusty = {:>) The lesson appears to be that if you do get the gearbox plated, powder = coated, painted or anodize, etc. to protect it from corrosion. make = certain to protect and/or clean off any deposit that gets where it = doesn't belong. Second if you encounter the unusual, don't proceed with = flight, I know - needless to say, but I'll say it anyhow, if you = encounter anything unusual on preflight - don't fly until you have = resolved it. Ed Anderson RV-6A N494BW Rotary Powered Matthews, NC eanderson@carolina.rr.com ------=_NextPart_000_001B_01C38DDD.456BFE20 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
As most of you know, I had planned on = attending the=20 South East Regional Fly in at Evergreen, Al this past weekend.  = Well, as=20 some of you suspect, I didn't make it.  I had not mentioned = anything before=20 this point as a gearbox problem developed and I wanted to give Tracy the = change=20 to inspect it before all the spectulation got started on a possible = cause. =20 I have approx 30 hours on the gear box at this point.
 
First, the problem was in the gearbox, = BUT IT HAD=20 NOTHING TO DO WITH TRACY CROOKS EXCELLENT and WELL =  DESIGNED GEAR BOX!!!  I will repeat that - the problem had = nothing=20 whatsoever to do with the gearbox design (or components or parts or = assembly) -=20 I am waiting for the drive to get shipped back so I can put it on the = aircraft=20 and fly to the Shady Bend flyin later this month.  Now with that = preamble=20 out of the way.  Here is the story:
 
Well, as I was doing my preflight = before my planned=20 departure  for SERFI last Friday morning, I noticed that the=20 engine was a bit harder than normal to turnover by pulling the prop = through=20 (something I always do as part of the preflight).  But, it was a = cold 39F=20 morning, so I initially just attributed the difficulty to that 50 weight = oil=20 being sluggish.  However, ANYTHING that is not as it normally is, = gets my=20 suspicions aroused.  That gut feeling has saved me more than once = and I=20 have learned to listen to it. 
 
I attempted to crank and = immediately noticed=20 that not only was it much slower than normally, but what really got my = attention=20 was the battery voltage dropping to 4-6 volts!  That was an = immediate clue=20 that plenty of starter current was flowing but it wasn't turning the = engine as=20 it should.  So I immediately stopped cranking and sat there trying = to think=20 the problem through. Got out and play with the prop some more. It was = plain hard=20 to turn - not just sluggish oil.
 
I though initially it might be the = engine bearings,=20 but once I noticed that the normal 1/2" of free play at the tip of the = prop was=20 gone (actually, it was there - just very hard to move) I suspected the = gear=20 box.  Well, took off the gear box and the engine turned over fine = so it=20 wasn't an engine problem, but I couldn't budge the prop flange.  So = rather=20 than destroy any forensic evidence by taking it apart myself, I sent it = back to=20 Tracy.
 
He just sent me an email detailing the = cause. =20 It appears that some nickel plating (some of you may not be aware- but, = I had=20 the aluminum casing of the gear box nickle coated for protection) had = gotten=20 deposited on the inside of the bronze pressure bearing on the end the = gearbox=20 nearest the prop.  For whatever reason, the Nickle accidently = deposited on=20 the bronze bearing by the plating process started flaking off and = some got=20 deposited and smeared onto the inner surface of  bronze oil = pressure=20 bearing.  Most of the flakes apparently pass through the = gear box=20 without effect.  However, the tolerance on the pressure bearing for = the=20 prop shaft is pretty small .0015-.002.  In any case, enough of the = nickel=20 plating had gotten smeared on the bronze bearing surface to reduce the = tolerance=20 to .0005 inch.  That was what was causing the = binding. 
 
 I had inspected the components = after I had=20 them plated, but apparently failed to notice a bit on the prop end of = the oil=20 pressure bearing, the plated nickle has a sort of gold tent to it which = makes it=20 blend with the bronze pretty well (at least to my eyeball). In any case, = as I=20 stated earlier, nothing to do with the gearbox per se, just my failure = to detect=20 and remove the nickle plating where it did not belong.  I really = appreciate=20 Tracy taking the time to inspect and fix the problem just before his = departure=20 for Copperstate - what a gent!
 
Tracy, said that because I caught it so = soon, there=20 was no damage to the shaft at all and only a very small groove in the=20 bronze.  He bored the bronze bearing sufficient to remove any = nickel=20 plating and the small groove and will be shipping it back this = week.  So it=20 looks like I will get to fly to Shady Bend after all.  Was not = looking=20 forward to the drive.
 
So now you know the story.  I had = not=20 mentioned the gearbox problem, because I did not think it useful =  to=20 do so until Tracy had a chance to determine what the problem was.  = Clearly=20 neither one of us wanted to think of a design problem (particularly = Tracy-I=20 imagine) and fortunately it was not.  I had not even considered a = possible=20 design problem as I knew that Tracy had over 400 hours on his and many = others=20 were flying out there.  It Just another one of those strange=20 happenings I seem to attract {:>) perhaps because I try = different things=20 - sort of like Rusty {:>)
 
The lesson appears to be that if you do = get the=20 gearbox plated, powder coated, painted or anodize, etc. to protect = it from=20 corrosion. make certain to protect and/or clean off any deposit that = gets where=20 it doesn't belong.  Second if you encounter the unusual, don't = proceed with=20 flight, I know - needless to say, but I'll say it anyhow, if you = encounter=20 anything unusual on preflight - don't fly until you have resolved=20 it.
 
Ed Anderson
RV-6A N494BW Rotary=20 Powered
Matthews, NC
eanderson@carolina.rr.com
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