X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from wproxy.gmail.com ([64.233.184.202] verified) by logan.com (CommuniGate Pro SMTP 5.0.6) with ESMTP id 930698 for flyrotary@lancaironline.net; Tue, 17 Jan 2006 20:34:43 -0500 Received-SPF: pass receiver=logan.com; client-ip=64.233.184.202; envelope-from=wdleonard@gmail.com Received: by wproxy.gmail.com with SMTP id i13so56147wra for ; Tue, 17 Jan 2006 17:33:59 -0800 (PST) DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=beta; d=gmail.com; h=received:message-id:date:from:to:subject:in-reply-to:mime-version:content-type:references; b=gm8Cy1Zx0qV+W7vJn5MkhD5rXj0hKSN08JfBUuwPMeK/8PBE7Vm9uV8d6HiANSWREe6aGmXxVsCSqbV95xwlJ1CQqq+bqUsUWZD97XeivugNRk41jZMuuJgk3bGTrVq0Hrs3kO2bxIxkxEsxE1hqra/tedE2hvKAOC54VWNJ0fY= Received: by 10.65.183.7 with SMTP id k7mr4332220qbp; Tue, 17 Jan 2006 17:33:58 -0800 (PST) Received: by 10.64.142.19 with HTTP; Tue, 17 Jan 2006 17:33:58 -0800 (PST) Message-ID: <1c23473f0601171733q17066821iac50d2616d30fbfc@mail.gmail.com> Date: Tue, 17 Jan 2006 17:33:58 -0800 From: David Leonard To: Rotary motors in aircraft Subject: Re: [FlyRotary] Re: Anatomy of an almost crash. In-Reply-To: MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_Part_5065_32095943.1137548038881" References: ------=_Part_5065_32095943.1137548038881 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable Content-Disposition: inline Bill, coolant temp is measured in the stock location, as the coolant leaves the block in the water pump housing. Oil temp is measured in the oil line to the PSRU which comes from the turbo oil line, which come out of the bloc= k at the front side housing (basically, after oil cooler temp) Dave Leonard On 1/16/06, William wrote: > > Where do you measure the coolant temp? (location), and where the oil temp= ? > > Bill Schertz > KIS Cruiser # 4045 > > ----- Original Message ----- > *From:* David Leonard > *To:* Rotary motors in aircraft > *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. > > I took the RV up to Mammoth to ski for the weekend. When I returned to th= e > 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 coolan= t > leak but I neglected to replace the antifreeze (big mistake #1). I estima= ted > 25/75 antifreeze/water and the temperatures were supposed to be in the lo= w > 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. > > 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. > > 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 t= he > 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 l= eft > the airport at 11:30 pm the temperature was -3 deg. This is obviously col= der > 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). > > 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 fix= ed > 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 t= o > burn oil. That issue was fixed as well. > > In order to temporize the radiator leak I decided to use a can of radiato= r > stop-leak and switch coolant to Evan's NPG. NPG is a pure propylene glyco= l > 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 t= he > 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. > > 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 th= e > flight to Bishop - 27 miles away and 3000 feet lower. There I would remov= e > 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?) > > The first 8 minutes of flight all systems were green. Then over the cours= e > 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 continu= e > to the lower Bishop airport. Then the alternator quit (buss voltage dropp= ed > 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 p= uff > of smoke coming in into the cockpit thought the heater vent (cowl air - n= ot > a heat muff). > > 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 significa= nt > 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. > > 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 t= he > 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 > intersections. I relayed my situation to the Bishop unicom and got a prom= pt > 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 spee= d > indicators. > > 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 an= y > traffic has plenty of time to see me and slow down while I am bleeding of= f > 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 > was tied down at the Bishop airport. I had no time or desire to remove th= e > cowl so the cause is still very unclear. A loss of the accessory belt wou= ld > 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 af= ter > making repairs. I should have circled Mammoth airport in order to test th= e > 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). > > 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 nex= t 8 > months while I deploy to Iraq. (Suggestions or offers for use of an adequ= ate > truck or trailer would be much appreciated). This will also give me a cha= nce > to paint the plane and do a lot of the finishing touches that will be eas= ier > 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. > > 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 a= nd > a half out of his day to drive back up to Mammoth and get my car for me. > > > -- > 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 > > -- 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 ------=_Part_5065_32095943.1137548038881 Content-Type: text/html; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable Content-Disposition: inline
Bill, coolant temp is measured in the stock location, as the coolant l= eaves the block in the water pump housing.  Oil temp is measured in th= e oil line to the PSRU which comes from the turbo oil line, which come out = of the block at the front side housing (basically, after oil cooler temp)
 
Dave Leonard

 
On 1/16/06, = William <wschertz@ispwest.co= m> wrote:
Where do you measure the coolant temp?= (location), and where the oil temp?
Bill Schertz
KIS Cruiser # 4045
----- Original Message -----
Sent: Monday, January 16, 2006 12:54= AM
Subject: [FlyRotary] Anatomy of an a= lmost crash.

 

I had to set my RV-6 down on highway 395 near Bishop Tuesday, and here i= s 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 rotar= y engine.=20

I took the RV up to Mammoth to ski for the weekend. When I returned to t= he plane Sunday evening I discovered a small puddle of coolant under the en= gine. 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 o= vernight. 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 so= me 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 ha= d 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 s= ome 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 cold= er than I had expected and was probably responsible for the damage. The tem= perature in town was 20 deg despite the fact that town is higher in elevati= on. 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 a= irport 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 d= etermined that the leak was indeed coming from somewhere in the radiator. T= here 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 (w= hich vents down in the gear leg) had frozen and was causing the turbo to bu= rn oil. That issue was fixed as well.=20

In order to temporize the radiator leak I decided to use a can of radiat= or stop-leak and switch coolant to Evan's NPG. NPG is a pure propylene glyc= ol 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 ti= red (had slept in the car overnight) but decided it was safe to make the fl= ight to Bishop - 27 miles away and 3000 feet lower. There I would remove th= e cowl and give everything a good look. Since the coolant leak had only los= t about a quart in 3 days, was now sealed and would be flown with low press= ure 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 cour= se of a minute the coolant temp went up to over 280, oil temp up to over 20= 0 (the highest it has ever been). Being about half-way I decided to continu= e to the lower Bishop airport. Then the alternator quit (buss voltage dropp= ed to=20 11.7 and battery showed a discharge). Then oil pressure dropped to zero, fo= llowed shortly after by the engine stopping to make power and a puff of smo= ke coming in into the cockpit thought the heater vent (cowl air - not a hea= t 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 fl= ight 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 windmil= ling. It turns out that overheating the engine had caused the loss of compr= ession on all rotor faces and this prevented me from stopping the windmilli= ng. I was seeing descent rates of 800-1000 fpm at 90 KIAS and it soon becam= e 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 oppo= sing traffic) that also seemed to be free of turns, power lines and interse= ctions. I relayed my situation to the Bishop unicom and got a prompt respon= se. 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 instrum= ents 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 woul= d 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. F= eeling 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 mo= untainous terrain (though there is no freeway in SoCal that would be as for= giving 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 adequ= ate truck or trailer would be much appreciated). This will also give me a c= hance 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 re= peat. All things considered, I feel quite lucky that things turned out so w= ell.

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



--
Dave Leonard
Turbo Rotary RV-6 N4VY
= http://mem= bers.aol.com/_ht_a/rotaryroster/index.html
http:= //members.aol.com/_ht_a/vp4skydoc/index.html
=



--
Dave Leonard
Turbo Rotary RV-6 N4= VY
http= ://members.aol.com/_ht_a/rotaryroster/index.html
http://members.aol.com/_ht_a/vp4skydoc/index.html=20 ------=_Part_5065_32095943.1137548038881--