X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from outbound-mail.dca.untd.com ([64.136.47.15] verified) by logan.com (CommuniGate Pro SMTP 5.2.13) with SMTP id 3577223 for flyrotary@lancaironline.net; Fri, 10 Apr 2009 23:12:12 -0400 Received-SPF: pass receiver=logan.com; client-ip=64.136.47.15; envelope-from=alwick@juno.com Received: from Penny (c-98-246-170-137.hsd1.or.comcast.net [98.246.170.137]) by smtpout06.dca.untd.com with SMTP id AABE8ACVEAVM9HRA for (sender ); Fri, 10 Apr 2009 20:11:32 -0700 (PDT) Message-ID: <9872028129B44A4D84CCF220A0F59632@Penny> From: "Al Wick" To: "Rotary motors in aircraft" References: In-Reply-To: Subject: Re: [FlyRotary] Re: [Lancair_ES] Re: Rotary Engines Date: Fri, 10 Apr 2009 20:11:21 -0700 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_00D7_01C9BA18.88EFD410" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Windows Mail 6.0.6001.18000 X-MimeOLE: Produced By Microsoft MimeOLE V6.0.6001.18049 X-ContentStamp: 90:45:409674320 X-MAIL-INFO: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 b55521707d112138b5e9557104091d99191485b92574010925d9443590d9f5a584d564952090206581ad914971743de010a09064e44990e150c400b0f0702d248035f05024657594996d356d71d0d45455a0e02dd1a4893594ed5535403981b585ed2155041574743074a9051974d90179bda1090509b09dd50d9130c4c181b98405bd4491053de031a020a0702970cdf0e0902034b1adc0f9617051c924b12415f1fd2d X-UNTD-OriginStamp: L941HVjjYzDhN3itp//mkOyXVmhfiGWV4hpKWH2PxoJIWx5U2dFP5A== X-UNTD-Peer-Info: 10.171.42.36|smtpout06.dca.untd.com|smtpout06.dca.untd.com|alwick@juno.com This is a multi-part message in MIME format. ------=_NextPart_000_00D7_01C9BA18.88EFD410 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable If my employer asked me to analyze the reliability of two different = systems. I then come back 10 minutes later and describe system A is = safer because it has 10 less moving parts. He'd kick me in the ass and = show me the door. There is no such method used by anyone in the = reliability field.=20 http://en.wikipedia.org/wiki/Reliability_engineering If you want to convince someone you have a more safe design, just = measure how often it fails. Just add up the total flight hours, add up = the number of failures. Failures / hours =3D MTBF. This is a very high = number on the rotary, but the cool thing is it looks like it's getting = much better. It's very important to consider the severity of the = failure. The rotary has some positive characteristics there...where you = can still limp home. So the FMEA is an excellent tool.=20 http://en.wikipedia.org/wiki/Failure_mode_and_effects_analysis -Al Wick Cozy IV powered by Turbo Subaru 3.0R with variable valve lift and cam = timing.=20 Artificial intelligence in cockpit, N9032U 240+ hours from Portland, = Oregon Glass panel design, Subaru install, Prop construct, Risk assessment = info: http://www.maddyhome.com/canardpages/pages/alwick/index.html ----- Original Message -----=20 From: Ed Anderson=20 To: Rotary motors in aircraft=20 Sent: Friday, April 10, 2009 7:29 AM Subject: [FlyRotary] Re: [Lancair_ES] Re: Rotary Engines Good run down, Mark. =20 Gary does mention the numerous parts on the rotor itself - and while = each rotor does have a high part count, you have to consider that each = rotor is the equivalent of 3 pistons - so in that context the parts = count is actually lower, not higher - its very seldom you ever hear of = any failure of rotor parts other than the occasional apex seal - wear = yes, failure - seldom. plus I have never heard of a rotor coming = through the block {:>) So, good questions and good answers from you. =20 One saying does come to mind - from our good friend, Tracy Crook. = ".If you're asking if you should do it, you probably shouldn't. If you = should be doing it, nobody can talk you out of it..". For 90% of = homebuilders, its probably not appropriate. =20 Ed Ed Anderson Rv-6A N494BW Rotary Powered Matthews, NC eanderson@carolina.rr.com http://www.andersonee.com http://www.dmack.net/mazda/index.html http://www.flyrotary.com/ http://members.cox.net/rogersda/rotary/configs.htm#N494BW http://www.rotaryaviation.com/Rotorhead%20Truth.htm -------------------------------------------------------------------------= ----- From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] = On Behalf Of Mark Steitle Sent: Friday, April 10, 2009 9:26 AM To: Rotary motors in aircraft Subject: [FlyRotary] Re: [Lancair_ES] Re: Rotary Engines =20 Gary,=20 =20 Thanks for adding a more technical tone to this discussion. Yes, I = was not accounting for all the misc pieces needed to make the rotary = run, but then I wasn't considering all the little pieces needed to make = a conventional piston engine run either. Of the pieces that normally = fail and end up poking out through the engine case, I think you'll agree = that the rotary has significantly fewer of those. In fact, I have never = seen a rotary with a thrown connecting rod. ;-) =20 Having a liquid cooling system is a two-edged sword, but its not = anything that can't be overcome with good engineering. For coolant = lines on my installation I used aluminum tubing connected to the engine = and radiator via "Wiggins" couplings. I monitor coolant pressure, = coolant level, and coolant temperature. Of course, if I catch a = Canadian goose in the radiator, it will likely loose its ability to cool = the engine, but then you have the same risk with an air-cooled engine. =20 As for the bsfc, do your numbers reflect the modern EFI systems, or = carbureted engines. Tracy Crook realized a significant improvement in = bsfc when he switched from carburetors to EFI. The new "Renesis" rotary = engine has a better bsfc due to the side exhaust ports. Anyway, I = prefer to consider it in "dollars per air-mile". By the time you factor = in the cost savings for purchasing and maintaining a rotary engine over = a certified engine, and that the rotary runs happily (prefers) on 89 UL = fuel (half the cost of avgas), the cost per mile tips significantly in = favor of the rotary. (Reading the recent post about the $2300.00 oil = pan practically brought tears to my eyes.) I guess its the German in me = that caused me to seek out something better, or different. =20 =20 Ahhhh... you mentioned the magic word, "turbo-charger". I built my = engine with the intention of turbo-charging as it was initially = turbo-charged in its former life. After much thought, I decided to = follow the KISS principle and go N/A. But there's a little voice in my = head that keeps whispering "turbo-charge". With the rotary's high = energy exhaust gasses, turbo's are a natural solution. Yes they add = weight, but not much more than my current exhaust system. Stay tuned... =20 One thing that I hadn't mentioned that could be considered a negative = for the rotary engine is that very few A&P's know anything about rotary = engines. Heck, very few auto mechanics know how to work on a rotary = engine. But, if I'm there with my repairman's certificate in hand, who = needs an A&P? Also, rotary parts are less plentiful if you get stuck in = some hole-in-the-wall town. But there is always UPS overnight. =20 =20 Gary, thanks again for your thoughtful post. I'm not trying to = convert anyone to a rotary engine, I only want to see it get a fair = shake. =20 =20 Mark S. =20 P.S. I've CC'd the Fly Rotary group as they need something to talk = about (the list has been rather quiet lately). =20 =20 =20 =20 On Fri, Apr 10, 2009 at 7:13 AM, Gary Casey = wrote: =20 I'll certainly have to commend Mark on the great work with the rotary = engine. I agree with his comments on almost every count. But... You probably should count ALL the parts in and around the engine to = have a fair comparison. For example, the air-cooled aircraft engine = cooling system has essentially no moving parts, unless you count the = vernitherm. Yes, the 3-rotor engine has only 4 MAJOR moving parts, but = each rotor has about 50 components. While that's not necessarily good = or bad, it's not an inherently simple solution. It rejects more heat to = the coolant and more of that to the oil (rotors are oil-cooled), making = the cooling system larger and potentially more complex. And the exhaust = is hotter and contains more aggressive pressure pulses, which have to be = taken care of by some sort of muffling. The ideal muffler is probably a = turbocharger, which can work very well on account of the pressure = pulses, but it probably takes a special high-temperature turbo that can = tolerate the up-to 2000 degree exhaust. The turbo adds weight and = complexity, but perhaps not more weight than an effective muffler. The = fact that the engine is inherently round and concentric with the output = shaft is a good thing, but probably more attractive for a wing-mounted = engine than one in front of the fuselage. The rotary engine almost = requires a speed reduction unit to make the power/weight come out = favorable, and I was not impressed with the design of the then-currently = available units, although they seem to work okay in practice. One big = thing that bothered me is that the efficiency is inherently lower than = that of a good piston engine, partly because the compression ratio is = limited to less than about 9 and the surface-volume ratio the combustion = chamber is higher. This penalty is probably 5 to 10%. All that being = said, the big attraction to me was, as Mark said, the rotary will rarely = completely fail, even if the coolant is lost. The apex seals might = disintegrate and parts warp, but it will most likely continue to produce = power for some time, unlike a piston engine. A long time ago we were = testing many rotaries and occasionally we would see a loss in power. = When the engine was shut down it welded itself together even though it = was still producing power. And the very things that make it less = efficient contribute to the fact that it can tolerate a variety of = fuels. And with boosting it can be made to produce a lot of reliable = power. =20 I seriously looked at 3 different approaches - a standard aircraft = engine, a direct-drive automotive piston engine, and a rotary. The = eventual deciding factors were that the automotive engine came out heavy = and the rotary engine burned more fuel. I really do like the rotary, = though. Gary =20 -------------------------------------------------------------------------= ----- From: Mark Steitle To: Lancair_ES@yahoogroups.com Sent: Thursday, April 9, 2009 2:27:21 PM Subject: Re: [Lancair_ES] Rotary Engines Dave,=20 =20 Since there were no other replies, I figured I would give my 2-cents = worth. =20 =20 I have been flying a 3-rotor Lancair ES for almost 2 years now with a = total of 110 hrs on the Hobbs. While it hasn't been without some = teething pains, all-in-all, it has been a very positive experience and I = would choose a rotary again if/when the opportunity presents itself. =20 =20 While I did the FWF myself, my installation and the Mistral are both = closely related. As an example, I could bolt a Mistral intake and/or = exhaust directly to my engine, and probably interchange many parts with = the Mistral 3-rotor. The Mistral folks have taken much of the rotary = engine technology, and refined and pakaged it into a (soon to be) = certified product. =20 My reasoning is based on my belief that the rotary is inheretly a = stronger engine (pistons are cast iron vs. aluminum), with only 4 = moving parts. If you read the recent AOPA story about the Cessna 400 = blowing an engine over Pennsylvania in the night, well, I had a similar = experience in a Cessna 152, only not at night. Like the chap in the = AOPA story, we too just barely made it to the nearest airport, with oil = pouring out from the cowl onto the runway. Since that incident, I have = been very leery of all conventional piston engines. Hence my decision = to go with a rotary. =20 =20 Gross weight on my ES was 2060 lbs. I typically climb out at 7000 - = 7200 rpm (2400 - 2500 prop rpm), climbing at between 1000 fpm and 1300 = fpm, burning 16 - 18 gph, 15 gph in regular cruise (6000 rpm) and around = 10 -12 gph in economy cruise (5100 rpm). (Keep in mind that the pistons = (rotors) turn at 1/3 the speed of the crankshaft, so they are only = turning 1733 rpm in economy cruise.) I can run either 100LL or mogas = (w/o alcohol) without worry and can lean the mixture aggressively = without worry of hurting the engine (no exhaust valves to burn). I can = pull the throttle to idle whenever and not risk shock cooling the = engine. Being fuel-injected, it will start cold, hot, or anywhere in = between. What's not to love? =20 =20 I mentioned some teething pains... those consisted of an early cooling = problem which was solved with an auxilary water-to-oil exchanger and a = cowl flap. I have also had a series of oil leaks, all from the oil pan = not being properly sealed. I finally pulled the pan, cleaned and = resealed it. Problem solved. The toughest issue to resolve has been = finding a muffler that could withstand the pounding of the rotary's = exhaust. I'm pretty sure that issue has been resolved by switching to = a DNA racing muffler, but I don't have enough hours on it yet to state = for certain. =20 Hopes this helps answer your question(s). =20 Mark S. =20 =20 =20 __._,_.___ Messages in this topic (5) Reply (via web post) | Start a new topic=20 Messages | Files | Photos | Links | Database | Polls | Members | = Calendar=20 To Post a message to the group, send it to: Lancair_ES@YahooGroups.com To Unsubscribe, send a blank message to: Lancair_ES-unsubscribe@YahooGroups.com If you have questions for the group administrator, send it to: Lancair_ES-owner@YahooGroups.com=20 Change settings via the Web (Yahoo! ID required)=20 Change settings via email: Switch delivery to Daily Digest | Switch = format to Traditional=20 Visit Your Group | Yahoo! Groups Terms of Use | Unsubscribe=20 Recent Activity Visit Your Group=20 Give Back Yahoo! for Good Get inspired by a good cause. Y! Toolbar Get it Free! easy 1-click access to your groups. Yahoo! Groups Start a group in 3 easy steps. Connect with others. . __,_._,___ =20 -Al Wick Cozy IV powered by Turbo Subaru 3.0R with variable valve lift and cam = timing.=20 Artificial intelligence in cockpit, N9032U 240+ hours from Portland, = Oregon Glass panel design, Subaru install, Prop construct, Risk assessment = info: http://www.maddyhome.com/canardpages/pages/alwick/index.html ------=_NextPart_000_00D7_01C9BA18.88EFD410 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
If my employer asked me to analyze the = reliability=20 of two different systems. I then come back 10 minutes later and describe = system=20 A is safer because it has 10 less moving parts. He'd kick me in the ass = and show=20 me the door. There is no such method used by anyone in the reliability = field.=20
 
http://en.w= ikipedia.org/wiki/Reliability_engineering
 
If you want to convince someone you = have a more=20 safe design, just measure how often it fails. Just add up the total = flight=20 hours, add up the number of failures. Failures / hours =3D MTBF. This is = a very=20 high number on the rotary, but the cool thing is it looks like it's = getting much=20 better. It's very important to consider the severity of the failure. The = rotary=20 has some positive characteristics there...where you can still limp home. = So the=20 FMEA is an excellent tool.
 
h= ttp://en.wikipedia.org/wiki/Failure_mode_and_effects_analysis<= /DIV>
 
-Al Wick
Cozy IV powered by Turbo = Subaru 3.0R=20 with variable valve lift and cam timing.
Artificial intelligence in = cockpit,=20 N9032U 240+ hours from Portland, Oregon
Glass panel design, Subaru = install,=20 Prop construct, Risk assessment info:
htt= p://www.maddyhome.com/canardpages/pages/alwick/index.html
 
 
----- Original Message -----
From:=20 Ed=20 Anderson
Sent: Friday, April 10, 2009 = 7:29=20 AM
Subject: [FlyRotary] Re: = [Lancair_ES] Re:=20 Rotary Engines

Good run = down,=20 Mark.

 

Gary does = mention the=20 numerous parts on the rotor  itself =96 and while each rotor does = have a=20 high part count, you have to = consider that=20 each rotor is the equivalent of 3 pistons =96 so in that = context the=20 parts count is actually lower, not higher =96 its very seldom you ever = hear of=20 any failure of rotor parts other than the occasional apex seal =  =96 wear=20 yes, failure =96 seldom.   plus I have never heard of a = rotor coming=20 through the block {:>)   So, good questions and good = answers from=20 you.

 

One saying = does come=20 to mind =96 from our good friend, Tracy Crook.  =93=85If you=92re = asking if you should=20 do it, you probably shouldn=92t. If you should be doing it, nobody can = talk you=20 out of it..=94.  For 90% of homebuilders, its = probably not=20 appropriate.

 

Ed

Ed=20 Anderson

Rv-6A = N494BW Rotary=20 Powered

Matthews,=20 NC

eanderson@carolina.rr.com

http://www.andersonee.com

http://www.dmack.net/mazda/index.html

http://www.flyrotary.com/

http://members.cox.net/rogersda/rotary/configs.htm#N494BW

http://www.r= otaryaviation.com/Rotorhead%20Truth.htm

From:=20 Rotary motors in aircraft = [mailto:flyrotary@lancaironline.net] On=20 Behalf Of Mark Steitle
Sent: Friday, April 10, 2009 = 9:26=20 AM
To: = Rotary motors in aircraft
Subject: [FlyRotary] Re: = [Lancair_ES] Re:=20 Rotary Engines

 

Gary,=20

 

Thanks for adding a more technical tone to = this=20 discussion.  Yes, I was not accounting for all the misc pieces = needed to=20 make the rotary run, but then I wasn't considering all the little = pieces=20 needed to make a conventional piston engine run either.  Of the = pieces=20 that normally fail and end up poking out through the engine case, I = think=20 you'll agree that the rotary has significantly fewer of those.  = In fact,=20 I have never seen a rotary with a thrown connecting rod. =20 ;-)

 

Having a liquid cooling system is a = two-edged sword,=20 but its not anything that can't be overcome with good = engineering. =20 For coolant lines on my installation I used aluminum tubing connected = to the=20 engine and radiator via "Wiggins" couplings.  I = monitor coolant=20 pressure, coolant level, and coolant temperature.  Of course, if = I catch=20 a Canadian goose in the radiator, it will likely loose its ability to = cool the=20 engine, but then you have the same risk with an air-cooled = engine. =20

As for the bsfc, do your numbers = reflect the=20 modern EFI systems, or carbureted engines.  Tracy Crook = realized a=20 significant improvement in bsfc when he switched from carburetors to=20 EFI.  The new "Renesis" rotary engine has a better bsfc = due to=20 the side exhaust ports.  Anyway, I prefer to = consider it=20 in "dollars per air-mile".  By the time you factor in the = cost=20 savings for purchasing and maintaining a rotary engine over a = certified=20 engine, and that the rotary runs happily (prefers) on 89 UL fuel = (half=20 the cost of avgas), the cost per mile tips significantly in favor = of the=20 rotary.  (Reading the recent post about the = $2300.00=20 oil pan practically brought tears to my eyes.)  I guess its the = German in=20 me that caused me to seek out something better, or = different. =20

 

Ahhhh... you mentioned the magic word,=20 "turbo-charger".  I built my engine with the intention=20 of turbo-charging as it was initially turbo-charged in its = former=20 life.  After much thought, I decided to follow the = KISS=20 principle and go N/A.  But there's a little voice in my head = that=20 keeps whispering "turbo-charge".  With the rotary's high energy = exhaust=20 gasses, turbo's are a natural solution.  Yes they add = weight, but=20 not much more than my current exhaust system.  Stay=20 tuned...

 

One thing that I hadn't mentioned that could = be=20 considered a negative for the rotary engine is that very few A&P's = know=20 anything about rotary engines.  Heck, very few auto mechanics = know how to=20 work on a rotary engine.  But, if I'm there with my repairman's=20 certificate in hand, who needs an A&P?  Also, rotary parts = are less=20 plentiful if you get stuck in some hole-in-the-wall town.  But = there is=20 always UPS overnight. 

 

Gary, = thanks=20 again for your thoughtful post.  I'm not trying to convert=20 anyone to a rotary engine, I only want to see it get a fair=20 shake.  

 

Mark S.

 

P.S.  I've CC'd the Fly Rotary group as = they need=20 something to talk about (the list has been rather quiet=20 lately).

 

 

 

 

On Fri, Apr 10, 2009 at 7:13 AM, Gary Casey = <casey.gary@yahoo.com>=20 wrote:

 

I'll certainly have to = commend Mark on=20 the great work with the rotary engine.  I agree with his comments = on=20 almost every count.  But...

You probably should count ALL = the parts=20 in and around the engine to have a fair comparison.  For example, = the=20 air-cooled aircraft engine cooling system has essentially no moving = parts,=20 unless you count the vernitherm.  Yes, the 3-rotor engine has = only 4=20 MAJOR moving parts, but each rotor has about 50 components. =  While that's=20 not necessarily good or bad, it's not an inherently simple solution. =  It=20 rejects more heat to the coolant and more of that to the oil (rotors = are=20 oil-cooled), making the cooling system larger and potentially more = complex.=20  And the exhaust is hotter and contains more aggressive pressure = pulses,=20 which have to be taken care of by some sort of muffling.  The = ideal=20 muffler is probably a turbocharger, which can work very well on = account of the=20 pressure pulses, but it probably takes a special high-temperature = turbo that=20 can tolerate the up-to 2000 degree exhaust.  The turbo adds = weight and=20 complexity, but perhaps not more weight than an effective muffler. =  The=20 fact that the engine is inherently round and concentric with the = output shaft=20 is a good thing, but probably more attractive for a wing-mounted = engine than=20 one in front of the fuselage.  The rotary engine almost requires = a speed=20 reduction unit to make the power/weight come out favorable, and I was = not=20 impressed with the design of the then-currently available units, = although they=20 seem to work okay in practice.  One big thing that bothered me is = that=20 the efficiency is inherently lower than that of a good piston engine, = partly=20 because the compression ratio is limited to less than about 9 and the=20 surface-volume ratio the combustion chamber is higher.  This = penalty is=20 probably 5 to 10%.  All that being said, the big attraction to me = was, as=20 Mark said, the rotary will rarely completely fail, even if the coolant = is=20 lost.  The apex seals might disintegrate and parts warp, but it = will most=20 likely continue to produce power for some time, unlike a piston = engine.=20  A long time ago we were testing many rotaries and occasionally = we would=20 see a loss in power.  When the engine was shut down it welded = itself=20 together even though it was still producing power.  And the very = things=20 that make it less efficient contribute to the fact that it can = tolerate a=20 variety of fuels.  And with boosting it can be made to produce a = lot of=20 reliable power.

 

I seriously looked at 3 = different=20 approaches - a standard aircraft engine, a direct-drive automotive = piston=20 engine, and a rotary.  The eventual deciding factors were that = the=20 automotive engine came out heavy and the rotary engine burned more = fuel.=20  I really do like the rotary, = though.

Gary

 

From: Mark=20 Steitle <msteitle@gmail.com>
To: Lancair_ES@yahoogroups.com
Sent: Thursday, April 9, 2009 = 2:27:21=20 PM
Subject: Re: = [Lancair_ES]=20 Rotary Engines

Dave, =

 

Since there were no other = replies, I=20 figured I would give my 2-cents worth. =20

 

I have been flying a 3-rotor = Lancair ES=20 for almost 2 years now with a total of 110 hrs on the Hobbs.  = While it=20 hasn't been without some teething pains, all-in-all, it has been a = very=20 positive experience and I would choose a rotary again if/when the = opportunity=20 presents itself. 

 

While I did the FWF = myself, my=20 installation and the Mistral are both closely related.  As = an=20 example, I could bolt a Mistral intake and/or exhaust directly to = my=20 engine, and probably interchange many parts with the Mistral = 3-rotor. =20 The Mistral folks have taken much of the rotary = engine technology,=20 and refined and pakaged it into a (soon to be) certified = product. =20    

My reasoning is based on my = belief that=20 the rotary is inheretly a stronger engine (pistons are cast iron = vs.=20 aluminum), with  only 4 moving parts.  If you read = the=20 recent AOPA story about the Cessna 400 blowing an engine over = Pennsylvania in the=20 night, well, I had a similar experience in a Cessna 152, only not at=20 night.  Like the chap in the AOPA story, we too just barely = made it=20 to the nearest airport, with oil pouring out from the cowl onto the=20 runway.  Since that incident, I have been very leery of all=20 conventional  piston engines.  Hence my decision to go with = a=20 rotary.  

 

Gross weight on my ES was = 2060 lbs. =20 I typically climb out at 7000 - 7200 rpm (2400 - 2500 prop rpm), = climbing=20 at between 1000 fpm and 1300 fpm, burning 16 - 18 gph, 15 = gph in=20 regular cruise (6000 rpm) and around 10 -12 gph in economy cruise = (5100=20 rpm).  (Keep in mind that the pistons (rotors) turn at 1/3 the = speed of=20 the crankshaft, so they are only turning 1733 rpm in economy=20 cruise.)  I can run either 100LL or mogas (w/o alcohol) = without=20 worry and can lean the mixture aggressively without worry of = hurting the=20 engine (no exhaust valves to burn).  I can pull the throttle to=20 idle whenever  and not risk shock cooling the=20 engine.  Being fuel-injected, it will start cold, hot, or = anywhere=20 in between.  What's not to love? =20

 

I mentioned some teething = pains... those=20 consisted of an early cooling problem which was solved with an = auxilary=20 water-to-oil exchanger and a cowl flap.  I have also had a series = of oil=20 leaks, all from the oil pan not being properly sealed.  I finally = pulled=20 the pan, cleaned and resealed  it.  Problem = solved. =20 The toughest issue to resolve has been finding a muffler that could = withstand=20 the pounding of the rotary's exhaust.  I'm pretty sure=20 that issue has been resolved  by switching to a DNA = racing=20 muffler, but I don't have enough hours on it yet to state for=20 certain.

 

Hopes this helps answer your=20 question(s).

 

Mark=20 S.

 

  

 

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-Al Wick
Cozy IV powered by Turbo Subaru 3.0R with variable = valve lift=20 and cam timing.
Artificial intelligence in cockpit, N9032U 240+ = hours from=20 Portland, Oregon
Glass panel design, Subaru install, Prop construct, = Risk=20 assessment info:
htt= p://www.maddyhome.com/canardpages/pages/alwick/index.html
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