X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from rv-out-0506.google.com ([209.85.198.235] verified) by logan.com (CommuniGate Pro SMTP 5.2.13) with ESMTP id 3578311 for flyrotary@lancaironline.net; Sun, 12 Apr 2009 13:53:14 -0400 Received-SPF: pass receiver=logan.com; client-ip=209.85.198.235; envelope-from=wdleonard@gmail.com Received: by rv-out-0506.google.com with SMTP id f9so1549080rvb.7 for ; Sun, 12 Apr 2009 10:52:37 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:mime-version:received:in-reply-to:references :date:message-id:subject:from:to:content-type; bh=mWN2Bf9rdY3kUg+DcqqPrDcSDNq1JwyoB+Wiwap/AbQ=; b=NngV637rvxqkopO41Aq6fDkTHZ+DCHP4NoV/Dfh4NmwQ0z+EU+wEasyKWwQif22oOP szgCVhv6RteYGz4gEp2FCDiFcVzqfxCT7gza+Ii/tmFGB9A0oTJdKH6pXrtH2B7CiIQh zlByWBolsCnwcD2wj0qXhbFNt76NAdMxKDTU8= DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :content-type; b=Zg0mCLsi6zkp8pSTeNGHgmMT3vEFrtZJGdR091nJLeYdrGwNlaOKFLs7naIasvXK+i gGGjKSs2j3bBOhDchoAc7koNeHk2dv5mPUjUJ2fA7P9W2dPq8f4pBNHNZ9mg43cXkJ8N AxZZzIeAdbzBYr8eknM335ACxMnMymY01eh94= MIME-Version: 1.0 Received: by 10.141.107.13 with SMTP id j13mr2380363rvm.251.1239558757305; Sun, 12 Apr 2009 10:52:37 -0700 (PDT) In-Reply-To: References: Date: Sun, 12 Apr 2009 10:52:37 -0700 Message-ID: <1c23473f0904121052y2a722642k9b3b64f0372fc3c7@mail.gmail.com> Subject: Re: [FlyRotary] Re : [FlyRotary] Re: Gary Casey was [FlyRotary] Re: Rotary Engines From: David Leonard To: Rotary motors in aircraft Content-Type: multipart/alternative; boundary=000e0cd13a2a684d3004675f4342 --000e0cd13a2a684d3004675f4342 Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: quoted-printable Thats right right, Marc. Also incidents that I recall: A coot with an out of CG that flew anyway and crashed he was known to Ken Welters, who (among others) advised him not to fly the plane. A guy somewhere on the west coast, on on any of the lists, who built some sort of plans built or personal design that crashed and burned on first flight. Details sketchy - though he was also advised by many that the plan= e was unsafe. He apparently also skipped his FAA inspection. (also fatal) One of the early Powersport installations in a nice looking pusher that developed a crack in the exhaust system (possibly due to faulty welding practices) and the hot exhaust caused vapor lock. One of the Powersport installations that was at Vans homecoming (one of those really nice RV-8s) had some sort of electrical system failure that caused a crash. Jim Mouser's old RV-6 crashed due to a reported pilot loss of control. I believe that left Ed as the last remaining flying plugs up installation. Ian Beale lost his first RV-6 due to a broken coolant line. No sure if any of those were already included on your list. Probably more that I don't know about. Still, the engine is sound and has a good power t= o weight ratio and small size. The devil is in the details. --=20 David Leonard Turbo Rotary RV-6 N4VY http://N4VY.RotaryRoster.net http://RotaryRoster.net On Sun, Apr 12, 2009 at 5:34 AM, wrote: > Also Mistral with an inadequate muffler. > > Marc Joseph > > ----- Message d'origine ----- > De: Mark Steitle > Date: Dimanche, 12 Avril 2009, 7:46 > Objet: [FlyRotary] Re: Gary Casey was [FlyRotary] Re: Rotary Engines > =C0: Rotary motors in aircraft > > > > Mike, > > > Has anyone ever tried to document the rotary incidents resulting in a > forced landing? > > > Here's what I recall from memory, so it likely is missing a few; > > > 3 forced landings due to ruptured oil coolers > > 1 forced landing due to apex seal coming out of its slot (rotor out > of spec) > > 1 forced landing due to improper assembly of engine (seal wedged > between rotor & side housing) > > 1 forced landing on highway due to catastrophic overheating of > engine > > 2 forced landings (one fatal) due to probable fuel system design > flaw > > 1 forced landing on highway due to ingestion of FOD. > > > There were a few others, such as turbo failures which allowed for > continued operation at reduced power, so we may or may not wish to includ= e > those here. > > > While a number of these incidents date back quite a few years, and we > have made excellent progress, it says to me that we still have room for > improvement in the peripheral department. The good news is that out of a= ll > of the incidents listed above, none of them were caused by a true engine > failure. That's where the rotary has really earned my respect as a viabl= e > a/c engine. > > > Pay attention to the details! > > > Mark S. > > > > > On Sat, Apr 11, 2009 at 9:22 PM, Mike Wills wrote: > >> > This has been an interesting thread. In the end, it doesnt really >> matter how many "major" parts you have - even a minor failure can bring = you >> down. While I believe the basic rotary engine itself is more fault toler= ant >> than a recip, the peripherals used in the typical rotary install are a l= ot >> more complex than a typical recip install. Since we rotary fliers dont h= ave >> the benefit of 70 years worth of experience flying behind the typical Ly= Con >> farm implement I think overall our odds are considerably worse. Comes do= wn >> to how well an individual engineer's his installation and there is a >> tremendous amount of variation here. >> >> > The dependence on electronics in the typical rotary install is a good >> example. I may be a little sensitive to this issue since I've been tryin= g to >> find an intermittent glitch (2 times in 22 hours of engine testing). >> >> > Mike Wills >> > RV-4 N144MW >> >> > ----- Original Message ----- >> *> From:* Ed Anderson >> *> To:* Rotary motors in aircraft >> >> >> *> Sent:* Saturday, April 11, 2009 7:31 AM >> *> Subject:* [FlyRotary] Gary Casey was [FlyRotary] Re: Rotary Engines >> >> >> > Good analysis and logic, Gary. >> >> >> >> > You=92d make a good addition to the =93rotary community=94. I have no= ticed >> over the 10 years I have been flying my rotary powered RV-6A that the >> problems have decreased considerably, the success rate and completion ra= te >> has gone up and first flights are now occurring without significant prob= lems >> =96 even cooling is OK {:>). I believe most of this improvement can be >> attributed to folks sharing their knowledge, problems and solutions with >> others - such as on this list. >> >> >> >> > I know that fewer parts count is often touted as one of the rotary >> benefit =96 and while it is true that the part count is lower, the most >> significant thing (in my opinion) is not only does the lower part count = help >> reliability (if it is not there =96 it can not break), but if you look a= the >> design of the eccentric shaft (for example) you notice the absence of th= e >> jogs in a typical crankshaft and their stress points. The thing is over= 3=94 >> in diameter at some points and does not have the same inertia loads born= by >> a piston crankshaft. The parts that are there are of very robust design= . >> Finally, the rotary is (I believe) more tolerant of damage and tends to = fail >> =93gradually and gracefully=94, it can take a licking and keep on tickin= g as the >> old saying goes. Only extended time and numbers will provide the true M= TBF >> for the rotary, but I believe it looks very promising. >> >> >> >> > Failure of rotary engines are extremely rare, but unfortunately, as >> with many alternative engine installations, auxiliary subsystems such as >> fuel and ignition frequently being one-off designs have been the cause o= f >> most failures =96 with probably fuel the prime culprit. The good news i= s that >> for some platforms (such as the RVs) we have pretty much established wha= t >> will make an installation successful. The Canard crowd is fast approach= ing >> that status with their somewhat more challenging cooling requirements be= ing >> over come. >> >> >> >> > Having lost a rotor during flight due to putting in high compression >> rotors with worn apex seal slots worn beyond specs (found this out later= =96 >> my fault for not being aware of this spec limit and checking it) which l= ed >> to apex seal failure and consequence lost of most of the power from one >> rotor, I was still able to maintain 6500 MSL at WOT and fuel mixture kno= b to >> full rich =96 flowing 14.5 GPH =96 a lot of it undoubtedly being blown = through >> the disabled rotor. Flew it back 60 miles to a suitable runway and made= a >> non-eventful landing. There was a small increase in vibration due to t= he >> power strokes no longer being balanced, but nothing bad and you could st= ill >> read the needles on the gauges. Other folks have had FOD damage to a ro= tor >> and also make it to a safe landing. Two folks lost cooling (one loss of >> coolant fluid , one lost of water pump) and while they did cook the engi= nes, >> both made it back to a safe landing. So all things considered, I think = the >> rotary continues to show that if the installation is designed properly, = it >> makes a very viable and reliable aircraft power plant. >> >> >> >> > Failure of rotary engines in aircraft are extremely rare, but >> unfortunately, as with many alternative engine installations, auxiliary >> subsystems such as fuel and ignition frequently being one-off designs - = have >> been the cause of most failures. The good news is that for some platfor= ms >> (such as the RVs) we have pretty much established what will make an >> installation successful. The Canard crowd is fast approaching that stat= us >> with their somewhat more challenging cooling requirements being over com= e. >> >> >> >> > My rotary installation cost me $6500 back in 1996, the primary cost >> being a rebuilt engine $2000 and the PSRU $2900. I have since purchased= a >> 1991 turbo block engine from Japan for $900 and rebuilt it myself for >> another $2200. My radiators (GM evaporator cores) cost $5.00 from the j= unk >> yard and another $50.00 each for having the bungs welded on. So dependi= ng >> on how much you buy and how much you build the price can vary considerab= ly. >> Today, I would say it would take a minimum of around $8000 and more >> nominally around $10000 for a complete rotary installation in an RV =96 = some >> folks could do it for less, some for more. >> >> >> >> > But, regardless of the technical merit (or not) in someone=92s mind, t= he >> crucial thing (in my opinion) is you need to address two personal factor= s: >> >> >> >> > 1. What is your risk tolerance? It doesn=92t really matter how sexy >> some =93exotic=94 engine installation may seem =96 if you are not comfor= table >> flying behind (or in front) of it, then it certainly does not makes sen= se >> to go that route. After all, this is supposed to have an element of fun= and >> enjoyment to it. >> >> >> >> > 2. What is your knowledge, experience and background (and you don=92t >> have to be an engineer) and do you feel comfortable with the level of >> involvement needed. >> >> >> >> > So hope you continue to contribute to expanding our knowledge and >> understanding of the rotary in its application to power plant for aircra= ft. >> >> >> >> >> >> > Best Regards >> >> >> >> > 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 *Gary Casey >> *> Sent:* Saturday, April 11, 2009 8:36 AM >> *> To:* Rotary motors in aircraft >> *> Subject:* [FlyRotary] Re: Rotary Engines >> >> >> >> > Just to add a few more comments and answers to the several excellent >> comments posted: >> >> >> >> > How many parts does it take to make a rotary rotate? Well, "parts >> aren't parts" in this case. Mark was right in that there are maybe 4 >> "major" components, but you have to define major. A piston engine certa= inly >> has far more major parts. Is a valve a "major" part? I think so. Is a >> rotor corner button a major part? Not sure, but probably not. Is each >> planet gear in the PSRU a major part? I say yes, and the PSRU is an >> integral part of the rotary engine. As someone correctly pointed out, i= t's >> not how many parts, but the reliability of the total system that counts. >> Just looking at the history of the rotary (which, from the implication = of >> another post) it's not that good, but I don't think it has anything to d= o >> with reliability of the concept. It's more to do with the experimental >> nature of the builds and installations. My original point, perhaps not = well >> expressed is that to say there are just 4 parts is an oversimplification= . >> But let's face it, to put in an engine that has had many thousands of >> identical predecessors is less "experimental" than one that hasn't.. >> >> >> >> > Are we ES drivers more conservative? Probably so, since the ES is >> probably one of the experimentals most similar to production aircraft, a= nd >> not just because the Columbia (can't force myself to say Cezzna :-) was = a >> derivative. Therefore, it tends to attract conservative builders and >> owners. Not surprising then that almost all ES's have traditional >> powerplants, with the most excellent exception of Mark. While there may= be >> more, I know of only two off-airport landings caused by engine failures = in >> the ES in almost 20 years of experience. One was caused by fuel starvat= ion >> right after takeoff (fatal) and one was caused by a PSRU failure in an a= uto >> engine conversion. So our old-fashioned conservative nature has served = us >> pretty well. >> >> >> >> > Yes, I was assuming that the rotary had electronic fuel injection and >> ignition, but that by itself doesn't change the inherent fuel efficiency= of >> the engine. Direct injection does have a potential to improve BSFC beca= use >> the fuel charge can be stratified. It will probably decrease available >> power, though. I think the best rotary will be 5% less efficient than t= he >> "best" piston engine(same refinements added to each). But I stated that= as >> a simple disadvantage - as Mark pointed out, it isn't that simple. The >> rotary already comes configured to run on auto gas. The piston engine c= an >> also be so configured, but the compression ratio reduction would reduce = its >> BSFC and maybe durability advantage. The total operating cost is certai= nly >> significantly less if auto gas can always be used to refuel. I assumed = in >> my assessment that it will only be available 50% of the time. The real >> disadvantage, which I failed to state, is that the extra fuel required f= or a >> given mission might be 5 or 10% higher and that negated the weight >> advantage, if only for long-range flights. >> >> >> >> > Is the engine less expensive? I did a thorough analysis of a >> direct-drive recip auto engine installation and my conclusion was that i= f >> the auto engine were equivalent in reliability to the aircraft engine it >> would likely cost just as much. Is the same true of the rotary? I'm no= t >> sure, but you have to consider the total cost, including engineering of = all >> the parts in the system, not just the core engine. I would love to do a >> rotary installation, but I don't think I could justify it by cost reduct= ion. >> >> >> >> > It wasn't mentioned in the posts, but some have claimed the rotary is >> "smoother" than a recip. I at first resisted that notion. Sure, any ro= tary >> given sufficient counterbalancing, is perfectly balanced. A 4-cylinder >> opposed recip is not - there is a significant secondary couple. The >> 6-cylinder opposed engine is perfectly balanced, but only for PRIMARY an= d >> SECONDARY forces and couples - higher order forces have never really bee= n >> analyzed, although they would be very small. And then consider the forc= es >> within the engine that have to be resisted by that long, heavy, but flex= ible >> crankshaft. So it isn't the mechanical balance that gives the rotary an >> advantage. Let's take a look at the the torsional pulsations, comparing= the >> 3-rotor against the 6-cylinder: A 6-cylinder engine has 3 power impulse= s >> per rotation, as does the 3-rotor, so they are the same, right? Wrong. >> They both incorporate 4 "stroke" cycles, meaning that there separate an= d >> sequential intake, compression, power and exhaust events so that is the = same >> for both. The power event, which is the source of the torque impulse, t= akes >> 1/2 of a crank rotation for the recip. In the rotary the power event >> requires 1/4 of a ROTOR rotation, but the rotor rotates at 1/3 crank >> rotation - the result is that the power impulse lasts 3/4 of a CRANK >> rotation, 50% longer than in a recip. Therefore, the torsional excitati= on >> delivered to the propeller, PSRU and to the airframe is significantly le= ss >> than for a recip. And if you analyze the actual forces imparted, they g= o >> down by the square of the rpm. The torsional vibration amplitude goes d= own >> by a factor of 4 just because the rpm of the rotary turns about twice as >> fast. If you've skipped to the bottom of the paragraph, as you probably >> should have :-), yes the rotary is "smoother" - a LOT smoother.. (my >> apologies to rotary purists, for simplicity I used the word "crankshaft"= for >> both engines) >> >> >> >> > But just because you can burn auto gas should you? The biggest >> problems with auto gas in recip aircraft have nothing to do with the eng= ine, >> but with the high vapor pressure of the fuel - it is more prone to vapor >> lock. The fuel systems of certified aircraft are not particularly well >> designed with regard to vapor lock. "Fortunately", rotary engines typic= ally >> have no mechanical fuel pump and are forced to rely on electric pumps. >> Fortunately because the pumps can be located at the very bottom of the >> aircraft and close to the fuel tanks, making vapor lock much less likely= . I >> would caution any builders to consider vapor lock possibilities very >> seriously, much more so if you intend to run auto gas. when I was going= to >> do this I planned to put one electric pump in the wing root of each wing= , >> feeding the engine directly(the check valve in the non-running pump prev= ents >> back-feeding). Redundancy was by a "crossfeed" line that could connect = the >> tanks together. >> >> >> >> > And thanks, Mark for - probably incorrectly - referring to me as a >> "good engineer". I'll have to put that in my resume! >> >> >> >> > Have a good day, >> >> > Gary >> >> > (do you allow us outsiders in your events? I'll park well away :-) >> >> >> >> >> >> >> >> >> > __________ Information from ESET NOD32 Antivirus, version of virus >> signature database 3267 (20080714) __________ >> >> > The message was checked by ESET NOD32 Antivirus. >> >> > http://www.eset.com >> >> >> >> >> > > > > -- > Homepage: http://www.flyrotary.com/ > Archive and UnSub: > http://mail.lancaironline.net:81/lists/flyrotary/List.html > > --000e0cd13a2a684d3004675f4342 Content-Type: text/html; charset=windows-1252 Content-Transfer-Encoding: quoted-printable
Thats right right, Marc.=A0 Also incidents that I recall:
=A0
A coot with an out of CG that flew anyway and crashed he was known to = Ken Welters, who (among others)=A0advised him not to fly the plane.
A guy somewhere on the west coast, on on any of the lists, who built s= ome sort of plans built or personal design that crashed and burned on first= flight.=A0 Details sketchy - though he was also advised by many that the p= lane was unsafe.=A0 He apparently also skipped his FAA inspection. (also fa= tal)
One of the early Powersport installations in a nice looking pusher tha= t developed a crack=A0in the exhaust system (possibly due to faulty welding= practices) and the hot exhaust caused vapor lock.
One of the Powersport installations that was at Vans homecoming (one o= f those really nice RV-8s) had some sort of electrical system failure that = caused a crash.
Jim Mouser's old RV-6 crashed due to a reported pilot loss of cont= rol.=A0 I believe that left Ed as the last remaining flying plugs up instal= lation.
Ian Beale lost his first RV-6 due to a broken coolant line.

No = sure if any of those were already included on your list.=A0 Probably more t= hat I don't know about.=A0 Still, the engine is sound and has a good po= wer to weight ratio and small size.=A0 The devil is in the details.

--
David Leonard

Turbo Rotary RV-6 N4VY
http://N4VY.RotaryRoster.net
http://RotaryRoster.net=



On Sun, Apr 12, 2009 at 5:34 AM, <jrmjosep= h@videotron.ca> wrote:
Also Mistral with= an inadequate muffler.
=A0
Marc Joseph

----- Message d'or= igine -----
De: Mark Steitle <msteitle@gmail.com>
Date: Dimanche, 12 Avril 2009, 7:46
Objet: [FlyRotary] Re: Gary Casey wa= s [FlyRotary] Re: Rotary Engines
=C0: Rotary motors in aircraft <flyrotary@lanc= aironline.net>=20


> Mike,
> Has anyone ever tried to = document the rotary incidents resulting in a forced landing?

> Here's what I reca= ll from memory, so it likely is missing a few;
=A0
> =A0=A0=A0 3 forced landings due to ruptured = oil coolers
> =A0=A0=A0 1 forced landing= due to apex seal coming out of its slot (rotor out of spec)
> =A0=A0=A0 1 forced landing due to imp= roper assembly of engine (seal wedged between rotor & side housing)
> =A0=A0=A0 1 forced landing= on highway due to catastrophic overheating of engine
> =A0=A0=A0 2 forced landings (one fatal) due = to probable fuel system design flaw=A0
> =A0=A0=A0 1 forced landing= on highway due to ingestion of FOD.=A0

> There were a few others, such as turbo failures which= allowed for continued operation at reduced power, so we may or may not wis= h to include those here.=A0

> While a number of thes= e incidents date back quite a few years, and we have made excellent progres= s, it says to me that we still have room for improvement in the peripheral = department.=A0 The good news is that out of all of the incidents listed abo= ve, none of them were caused by a true engine failure.=A0 That's where = the rotary has really earned my respect as a viable a/c engine.

> Pay attention to the d= etails!

> Mark S.


> On Sat, Apr 11, 2009 at 9:22 PM, Mike Wills <rv-4m= ike@cox.net> wrote:
> = This has been an interesting thread. In the end, it doesnt really matter ho= w many "major" parts you have - even a minor failure can bring yo= u down. While I believe the basic rotary engine itself is more fault tolera= nt than a recip, the peripherals used in the typical rotary install are a l= ot more complex than a typical recip install. Since we rotary fliers dont h= ave the benefit of 70 years worth of experience flying behind the typical L= yCon farm implement I think overall our odds are considerably worse. Comes = down to how well an individual engineer's his installation and there is= a tremendous amount of variation here.
=A0
> The dependence on electronics in the typical rotary install=A0= is a good example. I may be a little=A0sensitive to this issue since I'= ;ve been trying to find an intermittent glitch (2 times in 22 hours of engi= ne testing).
=A0
> Mike Wills
> RV-4 N144M= W=A0=A0
> <= /font>----- Original Message -----
> From: Ed Anderso= n
>= ; To: Rotary motors in aircraft


>= ; Sent: Saturday, April 11, 2009 7:31 AM
>= ; Subject: [FlyRotary] Gary Casey was [FlyRotary] Re: Rotary Eng= ines


> Good analysis and logic, Gary.

=A0

> You=92d make a good addition to the =93rotary community=94.= =A0 I have noticed over the 10 years I have been flying my rotary powered R= V-6A that the problems have decreased considerably, the success rate and co= mpletion rate has gone up and first flights are now occurring without signi= ficant problems =96 even cooling is OK {:>).=A0 I believe most of this i= mprovement can be attributed to folks sharing their knowledge, problems and= solutions with others - such as on this list.=A0

=A0

> I know that fewer parts count is often touted as one of the = rotary benefit =96 and while it is true that the part count is lower, the m= ost significant thing (in my opinion) is not only does the lower part count= help reliability (if it is not there =96 it can not break), but if you loo= k a the design of the eccentric shaft (for example) you notice the absence = of the jogs in a typical crankshaft and their stress points.=A0 The thing i= s over 3=94 in diameter at some points and does not have the same inertia l= oads born by a piston crankshaft.=A0 The parts that are there are of very r= obust design.=A0 Finally, the rotary is (I believe) more tolerant of damage= and tends to fail =93gradually and gracefully=94, it can take a licking an= d keep on ticking as the old saying goes.=A0 Only extended time and numbers= will provide the true MTBF for the rotary, but I believe it looks very pro= mising.

=A0

> Failure of rotary engines are extremely rare, but unfortunat= ely, as with many alternative engine installations, auxiliary subsystems su= ch as fuel and ignition frequently being one-off designs have been the caus= e of most failures =96 with probably fuel the prime culprit.=A0 The good ne= ws is that for some platforms (such as the RVs) we have pretty much establi= shed what will make an installation successful.=A0 The Canard crowd is fast= approaching that status with their somewhat more challenging cooling requi= rements being over come.

=A0

> =A0 Having lost a rotor during flight due to putting in high= compression rotors with worn apex seal slots worn beyond specs (found this= out later =96 my fault for not being aware of this spec limit and checking= it) which led to apex seal failure and consequence lost of most of the pow= er from one rotor, I was still able to maintain 6500 MSL at WOT and fuel mi= xture knob to full rich =96 flowing 14.5 GPH =96 a lot of it undoubtedly = =A0being blown through the disabled rotor.=A0 Flew it back 60 miles to a su= itable runway and made a non-eventful landing.=A0=A0 There was a small incr= ease in vibration due to the power strokes no longer being balanced, but no= thing bad and you could still read the needles on the gauges.=A0 Other folk= s have had FOD damage to a rotor and also make it to a safe landing.=A0 Two= folks lost cooling (one loss of coolant fluid , one lost of water pump) an= d while they did cook the engines, both made it back to a safe landing.=A0 = So all things considered, I think the rotary continues to show that if the = installation is designed properly, it makes a very viable and reliable airc= raft power plant.

=A0

> Failure of rotary engines in aircraft are extremely rare, bu= t unfortunately, as with many alternative engine installations, auxiliary s= ubsystems such as fuel and ignition frequently being one-off designs - have= been the cause of most failures.=A0 The good news is that for some platfor= ms (such as the RVs) we have pretty much established what will make an inst= allation successful.=A0 The Canard crowd is fast approaching that status wi= th their somewhat more challenging cooling requirements being over come.

=A0

> My rotary installation cost me $6500 back in 1996, the prima= ry cost being a rebuilt engine $2000 and the PSRU $2900.=A0 I have since pu= rchased a 1991 turbo block engine from Japan for $900 and rebuilt it myself= for another $2200. =A0My radiators (GM evaporator cores) cost $5.00 from t= he junk yard and another $50.00 each for having the bungs welded on.=A0 So = depending on how much you buy and how much you build the price can vary con= siderably.=A0 Today, I would say it would take a minimum of around $8000 an= d more nominally around $10000 for a complete rotary installation in an RV = =96 some folks could do it for less, some for more.

=A0

> But, regardless of the technical merit (or not) in someone= =92s mind, the crucial thing (in my opinion) is you need to address two per= sonal factors:

=A0

> 1.=A0 What is your risk tolerance?=A0 It doesn=92t really ma= tter how sexy some =93exotic=94 engine installation may seem =96 if you are= not comfortable flying behind (or in front) of it, then it certainly does = not =A0makes sense to go that route.=A0 After all, this is supposed to have= an element of fun and enjoyment to it.

=A0

> 2.=A0 What is your knowledge, experience and background (and= you don=92t have to be an engineer) and do you feel comfortable with the l= evel of involvement needed.

=A0

> So hope you continue to contribute to expanding our knowledg= e and understanding of the rotary in its application to power plant for air= craft.

=A0

=A0

> Best Regards

=A0

> Ed

=A0

=A0

> Ed Anderson

> Rv-6A N494BW Rotary Powered

> Matthews, NC

> eanderson@carolina.rr.com

> http://www.andersonee.com

> http://www.dmack.net/mazda/index.html<= /span>

>= http://www.flyrotary.com/

> http://members.cox.net/rogersda/rota= ry/configs.htm#N494BW

> http://www.rotaryaviation.com/Rotorhead%20Truth.htm<= /span>



&= gt; From: Rotary motors in aircraft [m= ailto:flyrotary@lancaironline.net] On Behalf Of Gary Casey
= > Sent: Saturday, April 11, 2009 8:36 AM
> To: Rotary motors in aircraft
= > Subject: [FlyRotary] Re: Rotary Engines


=A0

> Just to add a few more = comments and answers to the several excellent comments posted:


=A0


> How many parts does it = take to make a rotary rotate? =A0Well, "parts aren't parts" i= n this case. =A0Mark was right in that there are maybe 4 "major" = components, but you have to define major. =A0A piston engine certainly has = far more major parts. =A0Is a valve a "major" part? =A0I think so= . =A0Is a rotor corner button a major part? =A0Not sure, but probably not. = =A0Is each planet gear in the PSRU a major part? =A0I say yes, and the PSRU= is an integral part of the rotary engine. =A0As someone correctly pointed = out, it's not how many parts, but the reliability of the total system t= hat counts. =A0Just looking at the history of the rotary (which, from the i= mplication of another post) it's not that good, but I don't think i= t has anything to do with reliability of the concept. =A0It's more to d= o with the experimental nature of the builds and installations. =A0My origi= nal point, perhaps not well expressed is that to say there are just 4 parts= is an oversimplification. =A0But let's face it, to put in an engine th= at has had many thousands of identical predecessors is less "experimen= tal" than one that hasn't..


=A0


> Are we ES drivers more = conservative? =A0Probably so, since the ES is probably one of the experimen= tals most similar to production aircraft, and not just because the Columbia= (can't force myself to say Cezzna :-) was a derivative. =A0Therefore, = it tends to attract conservative builders and owners. =A0Not surprising the= n that almost all ES's have traditional powerplants, with the most exce= llent exception of Mark. =A0While there may be more, I know of only two off= -airport landings caused by engine failures in the ES in almost 20 years of= experience. =A0One was caused by fuel starvation right after takeoff (fata= l) and one was caused by a PSRU failure in an auto engine conversion. =A0So= our old-fashioned conservative nature has served us pretty well.


=A0


> Yes, I was assuming tha= t the rotary had electronic fuel injection and ignition, but that by itself= doesn't change the inherent fuel efficiency of the engine. =A0Direct i= njection does have a potential to improve BSFC because the fuel charge can = be stratified. =A0It will probably decrease available power, though. =A0I t= hink the best rotary will be 5% less efficient than the "best" pi= ston engine(same refinements added to each). =A0But I stated that as a simp= le disadvantage - as Mark pointed out, it isn't that simple. =A0The rot= ary already comes configured to run on auto gas. =A0The piston engine can a= lso be so configured, but the compression ratio reduction would reduce its = BSFC and maybe durability advantage. =A0The total operating cost is certain= ly significantly less if auto gas can always be used to refuel. =A0I assume= d in my assessment that it will only be available 50% of the time. =A0The r= eal disadvantage, which I failed to state, is that the extra fuel required = for a given mission might be 5 or 10% higher and that negated the weight ad= vantage, if only for long-range flights.


=A0


> Is the engine less expe= nsive? =A0I did a thorough analysis of a direct-drive recip auto engine ins= tallation and my conclusion was that if the auto engine were equivalent in = reliability to the aircraft engine it would likely cost just as much. =A0Is= the same true of the rotary? =A0I'm not sure, but you have to consider= the total cost, including engineering of all the parts in the system, not = just the core engine. =A0I would love to do a rotary installation, but I do= n't think I could justify it by cost reduction.


=A0


> It wasn't mentioned= in the posts, but some have claimed the rotary is "smoother" tha= n a recip. =A0I at first resisted that notion. =A0Sure, any rotary given su= fficient counterbalancing, is perfectly balanced. =A0A 4-cylinder opposed r= ecip is not - there is a significant secondary couple. =A0The 6-cylinder op= posed engine is perfectly balanced, but only for PRIMARY and SECONDARY forc= es and couples - higher order forces have never really been analyzed, altho= ugh they would be very small. =A0And then consider the forces within the en= gine that have to be resisted by that long, heavy, but flexible crankshaft.= =A0So it isn't the mechanical balance that gives the rotary an advanta= ge. =A0Let's take a look at the the torsional pulsations, comparing the= 3-rotor against the 6-cylinder: =A0A 6-cylinder engine has 3 power impulse= s per rotation, as does the 3-rotor, so they are the same, right? =A0Wrong.= =A0They both incorporate 4 "stroke" cycles, meaning that there s= eparate and sequential intake, compression, power and exhaust events so tha= t is the same for both. =A0The power event, which is the source of the torq= ue impulse,=A0takes 1/2 of a crank rotation for the recip. =A0In the rotary= the power event requires 1/4 of a ROTOR rotation, but the rotor rotates at= 1/3 crank rotation - the result is that the power impulse lasts 3/4 of a C= RANK rotation, 50% longer than in a recip. =A0Therefore, the torsional exci= tation delivered to the propeller, PSRU and to the airframe is significantl= y less than for a recip. =A0And if you analyze the actual forces imparted, = they go down by the square of the rpm. =A0The torsional vibration amplitude= goes down by a factor of 4 just because the rpm of the rotary turns about = twice as fast. =A0If you've skipped to the bottom of the paragraph, as = you probably should have :-), yes the rotary is "smoother" - a LO= T smoother.. (my apologies to rotary purists, for simplicity I used the wor= d "crankshaft" for both engines)


=A0


> But just because you ca= n burn auto gas should you? =A0The biggest problems with auto gas in recip = aircraft have nothing to do with the engine, but with the high vapor pressu= re of the fuel - it is more prone to vapor lock. =A0The fuel systems of cer= tified aircraft are not particularly well designed with regard to vapor loc= k. =A0"Fortunately", rotary engines typically have no mechanical = fuel pump and are forced to rely on electric pumps. =A0Fortunately because = the pumps can be located at the very bottom of the aircraft and close to th= e fuel tanks, making vapor lock much less likely. =A0I would caution any bu= ilders to consider vapor lock possibilities very seriously, much more so if= you intend to run auto gas. =A0when I was going to do this I planned to pu= t one electric pump in the wing root of each wing, feeding the engine direc= tly(the check valve in the non-running pump prevents back-feeding). =A0Redu= ndancy was by a "crossfeed" line that could connect the tanks tog= ether.


=A0


> And thanks, Mark for - = probably incorrectly - referring to me as a "good engineer". =A0I= 'll have to put that in my resume!


=A0


> Have a good day,=


> Gary

<= br>

> (do you allow us outsid= ers in your events? =A0I'll park well away :-)


=A0







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