X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from [216.52.245.18] (HELO ispwest-email1.mdeinc.com) by logan.com (CommuniGate Pro SMTP 5.0.6) with ESMTP id 928558 for flyrotary@lancaironline.net; Mon, 16 Jan 2006 12:25:44 -0500 Received-SPF: none receiver=logan.com; client-ip=216.52.245.18; envelope-from=wschertz@ispwest.com Received: from 7n7z201 (unverified [63.13.186.29]) by ispwest-email1.mdeinc.com (Vircom SMTPRS 4.3.450.0) with SMTP id for ; Mon, 16 Jan 2006 09:24:46 -0800 X-Modus-BlackList: 63.13.186.29=OK;wschertz@ispwest.com=OK X-Modus-RBL: 63.13.186.29=OK X-Modus-Trusted: 63.13.186.29=NO Message-ID: <060401c61ac1$b6acdc30$0400000a@7n7z201> From: "William" To: "Rotary motors in aircraft" References: Subject: Re: [FlyRotary] Anatomy of an almost crash. Date: Mon, 16 Jan 2006 11:24:28 -0600 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0601_01C61A8F.69EDDE80" 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_0601_01C61A8F.69EDDE80 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Dave, When you switched to Evans coolant, was it at 100% Proplyene Glycol? Bill Schertz KIS Cruiser # 4045 ----- Original Message -----=20 From: David Leonard=20 To: Rotary motors in aircraft=20 Sent: Monday, January 16, 2006 12:54 AM Subject: [FlyRotary] Anatomy of an almost crash. I had to set my RV-6 down on highway 395 near Bishop Tuesday, and here = is the story. Mostly things I could have done better, some that I did = right or otherwise got lucky. It is an RV6 tip up with a turbocharged = Mazda rotary engine.=20 I took the RV up to Mammoth to ski for the weekend. When I returned to = the plane Sunday evening I discovered a small puddle of coolant under = the engine. I had some concerns about the cold as my antifreeze had been = recently diluted with water when I had to make a field repair of a = coolant leak but I neglected to replace the antifreeze (big mistake #1). = I estimated 25/75 antifreeze/water and the temperatures were supposed to = be in the low 20's overnight. This I thought would be enough but I was = not sure. The puddle of coolant seemed to prove that overnight the temp = got low enough to freeze some coolant and crack something.=20 A quick look under the cowl failed to reveal the souce of the leak = other than it was not coming from the previously fixed coolant line or = anywhere other than the radiator itself. I didn't have time to trouble = shoot as I had to get home to be at work the next day.=20 I was able to hitch a ride home in another aircraft, then drive back = up the following evening after work. When I arrived at the airport at = 10pm the temperature was 3 deg F. In order to prevent any further = damage, I added some anti freeze and ran the engine for a while to = circulate it. When I left the airport at 11:30 pm the temperature was -3 = deg. This is obviously colder than I had expected and was probably = responsible for the damage. The temperature in town was 20 deg despite = the fact that town is higher in elevation. The only explanation I have = for the extreme low temp at the airport is temperature loss from = sublimation of the vast deep snow fields around the airport in the very = dry air (just a guess).=20 I arrived at sun-up the next morning (temp again 4 deg at airport but = 19 in town) and got to work on fixing the leak. After several engine = runs I determined that the leak was indeed coming from somewhere in the = radiator. There did not seem to be any coolant in the oil, but I = identified and fixed an oil leak in the turbo oil return line. Also, the = engine breather tube (which vents down in the gear leg) had frozen and = was causing the turbo to burn oil. That issue was fixed as well.=20 In order to temporize the radiator leak I decided to use a can of = radiator stop-leak and switch coolant to Evan's NPG. NPG is a pure = propylene glycol coolant that has a very high boiling temp and can = therefore be run with little or no coolant system pressure. I switched = out the coolant, added the stop-leak, and changed to a 7 psi radiator = cap. The stop-leak appeared to do it's job as there was no visible = continued leak after an hour of running the engine on the ground at fast = idle with some brief runs at higher RPM.=20 At about 2pm I was cold (temp at the airport now in the mid 20's) and = tired (had slept in the car overnight) but decided it was safe to make = the flight to Bishop - 27 miles away and 3000 feet lower. There I would = remove the cowl and give everything a good look. Since the coolant leak = had only lost about a quart in 3 days, was now sealed and would be flown = with low pressure I assumed the most I could loose in the 15 min flight = would be about a cup of coolant (Big mistake #2?)=20 The first 8 minutes of flight all systems were green. Then over the = course of a minute the coolant temp went up to over 280, oil temp up to = over 200 (the highest it has ever been). Being about half-way I decided = to continue to the lower Bishop airport. Then the alternator quit (buss = voltage dropped to 11.7 and battery showed a discharge). Then oil = pressure dropped to zero, followed shortly after by the engine stopping = to make power and a puff of smoke coming in into the cockpit thought the = heater vent (cowl air - not a heat muff).=20 It appeared as though I would be able to glide to the Bishop airport. = I was at 9000 feet. Bishop was 13 miles away at 4000 feet with no = significant winds. This distance is solidly within the typical glide = ratio of the RV6 so I calmly assumed there would be an easy dead-stick = onto the airport.=20 I tried to get the prop to stop windmilling by slowing. In my initial = flight testing I had been able to stop the prop from windmilling at = about 80 kts. However, even by slowing to 65kts IAS I was unable to stop = the windmilling. It turns out that overheating the engine had caused the = loss of compression on all rotor faces and this prevented me from = stopping the windmilling. I was seeing descent rates of 800-1000 fpm at = 90 KIAS and it soon became apparent that making the airport would be = sketchy at best, so I opted for a quality highway rather than try to = overfly the town to make the airfield.=20 I was able to spot a section of Hwy 395 that was 4-lane divided (no = opposing traffic) that also seemed to be free of turns, power lines and = intersections. I relayed my situation to the Bishop unicom and got a = prompt response. I turned off my fuel pump and in accordance with my = training turned off the master power on short final... Doh! I have all = electric flight instruments and now had no time to re-boot either of my = 2 air speed indicators.=20 My plan for traffic avoidance was to come in faster than typical = traffic speed, then bleed off that speed at 20 feet over the highway. = That way any traffic has plenty of time to see me and slow down while I = am bleeding off speed. Touchdown was uneventful and quite a relief. No = injury or damage.=20 The Bishop police were there within minutes, and 2 hours later the = plane was tied down at the Bishop airport. I had no time or desire to = remove the cowl so the cause is still very unclear. A loss of the = accessory belt would explain both the inability to cool and the loss of = the alternator, but my bet is still on something to do with the extreme = cold and radiator leak. I have to shamefully admit that time pressures = were a contributing factor. Feeling the need to return home, I probably = rushed the testing process after making repairs. I should have circled = Mammoth airport in order to test the repairs at high power before = attempting continued flight, especially in mountainous terrain (though = there is no freeway in SoCal that would be as forgiving as that section = of 395).=20 I plan to rent some kind of truck next weekend and drive up, remove = the wings, and bring the plane home. It will remain in our garage for = the next 8 months while I deploy to Iraq. (Suggestions or offers for use = of an adequate truck or trailer would be much appreciated). This will = also give me a chance to paint the plane and do a lot of the finishing = touches that will be easier to do at home than at the airport. Obviously = I will need to rebuild the engine as well, but that is a relatively = minor issue.=20 This was quite a learning experience I obviously hope I never have to = repeat. All things considered, I feel quite lucky that things turned out = so well. Lastly, I want to thank the Bishop Unicom, Police Dept, Highway = Patrol, Cal Trans, and Fire Department who were all very professional = and helpful. Also, thank you to the fellow RV6 owner was passing by and = took an hour and a half out of his day to drive back up to Mammoth and = get my car for me.=20 --=20 Dave Leonard Turbo Rotary RV-6 N4VY http://members.aol.com/_ht_a/rotaryroster/index.html http://members.aol.com/_ht_a/vp4skydoc/index.html ------=_NextPart_000_0601_01C61A8F.69EDDE80 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
Dave,
When you switched to Evans coolant, was = it at 100%=20 Proplyene Glycol?
 
Bill Schertz
KIS Cruiser # 4045
----- Original Message -----
From:=20 David=20 Leonard
Sent: Monday, January 16, 2006 = 12:54=20 AM
Subject: [FlyRotary] Anatomy of = an almost=20 crash.

I had to set my RV-6 down on highway 395 near Bishop Tuesday, and = here is=20 the story. Mostly things I could have done better, some that I did = right or=20 otherwise got lucky. It is an RV6 tip up with a turbocharged Mazda = rotary=20 engine.

I took the RV up to Mammoth to ski for the weekend. When I returned = to the=20 plane Sunday evening I discovered a small puddle of coolant under the = engine.=20 I had some concerns about the cold as my antifreeze had been recently = diluted=20 with water when I had to make a field repair of a coolant leak but I = neglected=20 to replace the antifreeze (big mistake #1). I estimated 25/75 = antifreeze/water=20 and the temperatures were supposed to be in the low 20's overnight. = This I=20 thought would be enough but I was not sure. The puddle of coolant = seemed to=20 prove that overnight the temp got low enough to freeze some coolant = and crack=20 something.

A quick look under the cowl failed to reveal the souce of the leak = other=20 than it was not coming from the previously fixed coolant line or = anywhere=20 other than the radiator itself. I didn't have time to trouble shoot as = I had=20 to get home to be at work the next day.

I was able to hitch a ride home in another aircraft, then drive = back up the=20 following evening after work. When I arrived at the airport at 10pm = the=20 temperature was 3 deg F. In order to prevent any further damage, I = added some=20 anti freeze and ran the engine for a while to circulate it. When I = left the=20 airport at 11:30 pm the temperature was -3 deg. This is obviously = colder than=20 I had expected and was probably responsible for the damage. The = temperature in=20 town was 20 deg despite the fact that town is higher in elevation. The = only=20 explanation I have for the extreme low temp at the airport is = temperature loss=20 from sublimation of the vast deep snow fields around the airport in = the very=20 dry air (just a guess).

I arrived at sun-up the next morning (temp again 4 deg at airport = but 19 in=20 town) and got to work on fixing the leak. After several engine runs I=20 determined that the leak was indeed coming from somewhere in the = radiator.=20 There did not seem to be any coolant in the oil, but I identified and = fixed an=20 oil leak in the turbo oil return line. Also, the engine breather tube = (which=20 vents down in the gear leg) had frozen and was causing the turbo to = burn oil.=20 That issue was fixed as well.

In order to temporize the radiator leak I decided to use a can of = radiator=20 stop-leak and switch coolant to Evan's NPG. NPG is a pure propylene = glycol=20 coolant that has a very high boiling temp and can therefore be run = with little=20 or no coolant system pressure. I switched out the coolant, added the=20 stop-leak, and changed to a 7 psi radiator cap. The stop-leak appeared = to do=20 it's job as there was no visible continued leak after an hour of = running the=20 engine on the ground at fast idle with some brief runs at higher RPM. =

At about 2pm I was cold (temp at the airport now in the mid 20's) = and tired=20 (had slept in the car overnight) but decided it was safe to make the = flight to=20 Bishop - 27 miles away and 3000 feet lower. There I would remove the = cowl and=20 give everything a good look. Since the coolant leak had only lost = about a=20 quart in 3 days, was now sealed and would be flown with low pressure I = assumed=20 the most I could loose in the 15 min flight would be about a cup of = coolant=20 (Big mistake #2?)

The first 8 minutes of flight all systems were green. Then over the = course=20 of a minute the coolant temp went up to over 280, oil temp up to over = 200 (the=20 highest it has ever been). Being about half-way I decided to continue = to the=20 lower Bishop airport. Then the alternator quit (buss voltage dropped = to 11.7=20 and battery showed a discharge). Then oil pressure dropped to zero, = followed=20 shortly after by the engine stopping to make power and a puff of smoke = coming=20 in into the cockpit thought the heater vent (cowl air - not a heat = muff).

It appeared as though I would be able to glide to the Bishop = airport. I was=20 at 9000 feet. Bishop was 13 miles away at 4000 feet with no = significant winds.=20 This distance is solidly within the typical glide ratio of the RV6 so = I calmly=20 assumed there would be an easy dead-stick onto the airport.

I tried to get the prop to stop windmilling by slowing. In my = initial=20 flight testing I had been able to stop the prop from windmilling at = about 80=20 kts. However, even by slowing to 65kts IAS I was unable to stop the=20 windmilling. It turns out that overheating the engine had caused the = loss of=20 compression on all rotor faces and this prevented me from stopping the = windmilling. I was seeing descent rates of 800-1000 fpm at 90 KIAS and = it soon=20 became apparent that making the airport would be sketchy at best, so I = opted=20 for a quality highway rather than try to overfly the town to make the=20 airfield.

I was able to spot a section of Hwy 395 that was 4-lane divided (no = opposing traffic) that also seemed to be free of turns, power lines = and=20 intersections. I relayed my situation to the Bishop unicom and got a = prompt=20 response. I turned off my fuel pump and in accordance with my training = turned=20 off the master power on short final... Doh! I have all electric flight = instruments and now had no time to re-boot either of my 2 air speed=20 indicators.

My plan for traffic avoidance was to come in faster than typical = traffic=20 speed, then bleed off that speed at 20 feet over the highway. That way = any=20 traffic has plenty of time to see me and slow down while I am bleeding = off=20 speed. Touchdown was uneventful and quite a relief. No injury or = damage.

The Bishop police were there within minutes, and 2 hours later the = plane=20 was tied down at the Bishop airport. I had no time or desire to remove = the=20 cowl so the cause is still very unclear. A loss of the accessory belt = would=20 explain both the inability to cool and the loss of the alternator, but = my bet=20 is still on something to do with the extreme cold and radiator leak. I = have to=20 shamefully admit that time pressures were a contributing factor. = Feeling the=20 need to return home, I probably rushed the testing process after = making=20 repairs. I should have circled Mammoth airport in order to test the = repairs at=20 high power before attempting continued flight, especially in = mountainous=20 terrain (though there is no freeway in SoCal that would be as = forgiving as=20 that section of 395).

I plan to rent some kind of truck next weekend and drive up, remove = the=20 wings, and bring the plane home. It will remain in our garage for the = next 8=20 months while I deploy to Iraq. (Suggestions or offers for use of an = adequate=20 truck or trailer would be much appreciated). This will also give me a = chance=20 to paint the plane and do a lot of the finishing touches that will be = easier=20 to do at home than at the airport. Obviously I will need to rebuild = the engine=20 as well, but that is a relatively minor issue.

This was quite a learning experience I obviously hope I never have = to=20 repeat. All things considered, I feel quite lucky that things turned = out so=20 well.

Lastly, I want to thank the Bishop Unicom, Police Dept, Highway = Patrol, Cal=20 Trans, and Fire Department who were all very professional and helpful. = Also,=20 thank you to the fellow RV6 owner was passing by and took an hour and = a half=20 out of his day to drive back up to Mammoth and get my car for me. =


--
Dave Leonard
Turbo Rotary RV-6 N4VY
http://memb= ers.aol.com/_ht_a/rotaryroster/index.html
http://members= .aol.com/_ht_a/vp4skydoc/index.html=20 ------=_NextPart_000_0601_01C61A8F.69EDDE80--