X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Mon, 26 Nov 2007 14:47:54 -0500 Message-ID: X-Original-Return-Path: Received: from smtp0.av-mx.com ([137.118.16.56] verified) by logan.com (CommuniGate Pro SMTP 5.2c1) with ESMTP id 2504477 for lml@lancaironline.net; Sun, 25 Nov 2007 15:35:56 -0500 Received-SPF: pass receiver=logan.com; client-ip=137.118.16.56; envelope-from=pinetownd@volcano.net Received: from DennisDell (65-166-100-129.dsl.volcano.net [65.166.100.129]) (Authenticated sender: pinetownd@volcano.net) by smtp0.av-mx.com (Postfix) with ESMTP id F3F281BF2F4 for ; Sun, 25 Nov 2007 15:35:17 -0500 (EST) X-Original-Message-ID: <008801c82fa2$adbf1e10$6501a8c0@DennisDell> From: "Dennis Johnson" X-Original-To: "Lancair Mailing List" Subject: Flying in Rain X-Original-Date: Sun, 25 Nov 2007 12:35:11 -0800 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0085_01C82F5F.9ECC5910" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2900.3138 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.3198 This is a multi-part message in MIME format. ------=_NextPart_000_0085_01C82F5F.9ECC5910 Content-Type: text/plain; charset="Windows-1252" Content-Transfer-Encoding: quoted-printable Greetings, I flew my Legacy from northern California to the Portland, Oregon, area = (McMinnville KMMV) and back the weekend before Thanksgiving. On the way = up, I flew through a lot of rain, including a very heavy rainstorm. The = airplane sat on the ground for 48 hours, exposed to rain most of the = time. On the way home, I again flew through heavy rain. My total time = flying in rain this trip could have been two hours. My true airspeed = was 210 knots or so. The good news is that I haven't found any paint chips on the leading = edge of the wing, although I found three tiny chips on the leading edge = of the air intakes on the front of the cowling. This success might be = because I was careful not to use any micro on the wing leading edge and = to keep the thickness of paint primer (WLS) on the leading edge thin. = My hypothesis is that paint chips caused by flying in rain are not a = failure of the paint, but a failure of the underlying material. I think = that micro and primer are somewhat soft and more likely to fail under = impact. I used flox with some cabo-sil, on the wing leading edges, = avoiding micro and avoiding a thick film of primer. It was harder to = sand, but possibly more resistant to chipping. I extensively rebuilt the air intakes on the cowling and may have gotten = a little lazy about avoiding micro there because of all the bodywork I = was doing, which might explain the chips I received in that area. I = don't know. The bad news is that a few days after returning home, while doing a = normal post-trip inspection, I discovered some water on the floor behind = the pilot's seat, in the baggage area. The more I looked, the more = water I found. It was behind the aft wing spar in the baggage area, in = the tunnel in the baggage area, at the aft baggage bulkhead, and at the = autopilot pitch servo bulkhead. I soaked up the water with a towel and = wrung it out into a bucket. I collected about a gallon of water! =20 So where did all that water come from? I think it came from the tail = and moved forward. I have heard that the cockpit and aft fuselage are at low pressure = during flight, so it's possible that the water was sucked into the tail = through openings in the aft spar for the vertical stabilizer and the = elevator bellcrank. (I don't understand how that could be, but it's a = possibility.) The water would have collected behind a bulkhead until = the water level got higher than the lowest opening in the bulkhead. At = that point, additional water would flow downhill to the next bulkhead, = where the process would be repeated. That's certainly what it looked = like when I was bailing it out. It could also have entered through those same holes in the aft vertical = stabilizer spar while the airplane was sitting on the ground in the rain = for 48 hours. If so, it would have traveled forwards in the same manner = as described in the previous paragraph. It's hard to imagine that a = gallon of water could have dripped into the airplane, though. =20 If the water is entering the tail while the plane is parked in the rain, = then drilling a drain hole in the bottom of the fuselage, at the first = place the water will collect, would be one solution. If it's sucking in = during flight, that's a harder problem to solve. I suppose I could put = a drain in the bottom of the fuselage, with an opening fabricated so = that it would suck air and water out of the fuselage, but I'm not sure. Anybody else had this problem? Anybody else solved this problem? Independently of finding the water puddles, I decided to avoid such wet = trips in the future, although I'm sure I'll fly through rain from time = to time. But preflighting in the rain, opening the canopy in the rain, = etc. isn't any fun. Plus, even more important, my wife didn't like it. Regards, Dennis Johnson Legacy, now over 100 hours tach time PS I understand that many pilots would have cancelled the trip, and avoided = the risk of flying in bad weather. Each of us makes his own decision in = that regard, and I respect pilots who might have made a different = decision. I was comfortable with the risks. I studied the weather and talked to = pilots who had local knowledge. There was no convective activity. = Ceilings were reasonably high throughout most of the flight. Ice was a = big concern. I developed a plan to minimize that risk, which worked = perfectly. I had enough fuel to get to CAVU weather. I'm comfortable = flying an ILS to minimums. ------=_NextPart_000_0085_01C82F5F.9ECC5910 Content-Type: text/html; charset="Windows-1252" Content-Transfer-Encoding: quoted-printable
Greetings,
 
I flew my Legacy from northern California to the Portland, = Oregon,=20 area (McMinnville KMMV) and back the weekend before Thanksgiving.  = On the=20 way up, I flew through a lot of rain, including a very heavy = rainstorm. =20 The airplane sat on the ground for 48 hours, exposed to rain most of the = time.  On the way home, I again flew through heavy rain.  My=20 total time flying in rain this trip could have been two=20 hours.  My true airspeed was 210 knots or so.
 
The good news is that I haven't found any paint chips on the = leading edge=20 of the wing, although I found three tiny chips on the leading edge of = the air=20 intakes on the front of the cowling.  This success might = be because I=20 was careful not to use any micro on the wing leading edge and to = keep the=20 thickness of paint primer (WLS) on the leading edge thin.  My = hypothesis is=20 that paint chips caused by flying in rain are not a failure of = the=20 paint, but a failure of the underlying material.  I think that = micro and=20 primer are somewhat soft and more likely to fail under = impact.  I used=20 flox with some cabo-sil, on the wing leading edges, avoiding micro = and=20 avoiding a thick film of primer.  It was harder to sand, but = possibly more=20 resistant to chipping.
 
I extensively rebuilt the air intakes on the cowling and may = have=20 gotten a little lazy about avoiding micro there because of all the = bodywork I=20 was doing, which might explain the chips I received in that area.  = I don't=20 know.
 
The bad news is that a few days after returning home, while doing a = normal=20 post-trip inspection, I discovered some water on the floor behind=20 the pilot's seat, in the baggage area.  The more I = looked, the=20 more water I found.  It was behind the aft wing spar in the baggage = area,=20 in the tunnel in the baggage area, at the aft baggage bulkhead, and=20 at the autopilot pitch servo bulkhead.  I soaked up = the=20 water with a towel and wrung it out into a bucket.  I collected = about a=20 gallon of water! 
 
So where did all that water come from?  I think it came = from the=20 tail and moved forward.
 
I have heard that the cockpit and aft fuselage are at low = pressure during flight, so it's possible that the water was sucked = into the=20 tail through openings in the aft spar for the vertical stabilizer and = the=20 elevator bellcrank.  (I don't understand how that could be, = but it's a=20 possibility.)  The water would have collected behind a bulkhead = until the=20 water level got higher than the lowest opening in the=20 bulkhead.  At that point, additional water would flow downhill = to the=20 next bulkhead, where the process would be repeated.  That's = certainly what=20 it looked like when I was bailing it out.
 
It could also have entered through those same holes in the aft = vertical stabilizer spar while the airplane was sitting on the = ground=20 in the rain for 48 hours.  If so, it would have traveled forwards = in the=20 same manner as described in the previous paragraph.  It's hard to = imagine=20 that a gallon of water could have dripped into the airplane, = though. =20
 
If the water is entering the tail while the plane is parked in the = rain,=20 then drilling a drain hole in the bottom of the fuselage, at the first = place the=20 water will collect, would be one solution.  If it's sucking in = during=20 flight, that's a harder problem to solve.  I suppose I could put a = drain in=20 the bottom of the fuselage, with an opening fabricated so that it = would=20 suck air and water out of the fuselage, but I'm not sure.
 
Anybody else had this problem?  Anybody else solved this=20 problem?
 
Independently of finding the water puddles, I decided to avoid = such=20 wet trips in the future, although I'm sure I'll fly through rain from = time to=20 time.  But preflighting in the rain, opening the canopy = in the=20 rain, etc. isn't any fun.  Plus, even more important, my wife = didn't=20 like it.
 
Regards,
Dennis Johnson
Legacy, now over 100 hours tach time
 
PS
I understand that many pilots would have cancelled the trip, = and=20 avoided the risk of flying in bad weather.  Each of us makes his = own=20 decision in that regard, and I respect pilots who might have = made a=20 different decision.
 
I was comfortable with the risks.  I studied the weather = and=20 talked to pilots who had local knowledge.  There was no convective=20 activity.  Ceilings were reasonably high throughout most of the=20 flight.  Ice was a big concern.  I developed a plan to = minimize that=20 risk, which worked perfectly.  I had enough fuel to get to = CAVU=20 weather.  I'm comfortable flying an ILS to=20 minimums.    
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