X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from mail-gx0-f176.google.com ([209.85.217.176] verified) by logan.com (CommuniGate Pro SMTP 5.2.13) with ESMTP id 3579711 for flyrotary@lancaironline.net; Mon, 13 Apr 2009 16:48:14 -0400 Received-SPF: pass receiver=logan.com; client-ip=209.85.217.176; envelope-from=wdleonard@gmail.com Received: by gxk24 with SMTP id 24so3221631gxk.19 for ; Mon, 13 Apr 2009 13:47:40 -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=UTT/qCDwSBwoGaHG6aheScxFVWGHNunLTjMKxb3bgB0=; b=U/wG1QEpn3zq/K/G73pOIc9bMCYQRf/sMXJF6bu2sqymWhjR57P0gPRgv1XZqBso8K nOL2a4bQsYUUNBrUuhiGOCNizOHv02V/2ckY14k+afPDKXMaK+vXk/gtqmpH2Nm6EoSh 9Mm06QDv7b7Jh+tzjCW+q++4GlCGwGCBS36Ps= 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=s9KyXj8rhLlgEHSXNBjS5JahuvRHqE5jHSIRR50XDYT6gIvsNxeppQzs1gyHpkHxPc VvHGnJvHWamV2xOvgogp/vJEndVjQpR78wXgB+8WtKku9I5zTOsZ0vnqiFsJhkPP6ty5 rdn6ktG7k0VouE6kfTdt7ybXvyVWakdkqzQlk= MIME-Version: 1.0 Received: by 10.90.71.15 with SMTP id t15mr8811384aga.45.1239655659977; Mon, 13 Apr 2009 13:47:39 -0700 (PDT) In-Reply-To: References: Date: Mon, 13 Apr 2009 13:47:39 -0700 Message-ID: <1c23473f0904131347i45e2d017l6ba28fa62d4aa148@mail.gmail.com> Subject: Re: [FlyRotary] Re: forced landings From: David Leonard To: Rotary motors in aircraft Content-Type: multipart/alternative; boundary=00163630f2df41bff7046775d3a2 --00163630f2df41bff7046775d3a2 Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: quoted-printable Mark, Thanks for putting together this database. I agree with you and Al G. that we should keep it to issues with the engine and it's systems. But I also agree with John and Al W. that we should somewhere include things that probably would have caused an in-flight failure, especially when found on pre-flight, run-up or take off roll. That is good stuff. Not the idiot-pilot-owner stuff like forgetting to attach the return fuel line, but the alternator bracket and PSRU issues etc - that could really help someone= . Similarly, just because it is in flight does not make it newsworthy. Like the intake hose blow offs that John and I have both experienced. Sure, something happened and you are damn sure going to return to the airport and check it out even though you are pretty sure you know what happened and it will not affect the safety of flight. OOps, didn't tighten that hose tight enough. In other words, I think Johns incident #1 is far more significant than incident #4. Maybe to clarify: #1 caused actual damage to the engine AND he NEEDED to land soon because of oil loss. Power produced was less than normally aspirated power. This is an interesting mechanical possibility (that a turbine blade somehow got BAC= K into the engine to bust the apex seal) and something important to consider when designing a turbo install. #4 caused only a reduction to normally aspirated power and a skipped heart beat or two. No damage, no real need to land other than as a precaution. No design flaw or mechanical issue - just an underestimation on how tight t= o make the hose clamp. (and believe me, they have to be very tight if there i= s no bead under the hose.) --=20 David Leonard Turbo Rotary RV-6 N4VY http://N4VY.RotaryRoster.net http://RotaryRoster.net On Mon, Apr 13, 2009 at 6:16 AM, Mark Steitle wrote: > Dave, > > I have decided to take Al's suggestion and limit the criteria for the > spreadsheet to basically include any in-flight system failure which > interrupts the planned flight and results in a premature landing. Based = on > this, I will add #3 & #4 as well as the one resulting from a ruptured > coolant hose. > > Mark S. > > On Mon, Apr 13, 2009 at 7:55 AM, David Leonard wro= te: > >> Mark, And did you get these? Added by me and John Slade under the wrong >> thread title: >> >> >> On Sun, Apr 12, 2009 at 5:15 PM, John Slade >> wrote: >> >> Here's a few for the list, Mark, >> 1. Stock turbo bearings collapsed & took out apex seal. Flew home at >> reduced power. >> >> 2. Fuel filer (sinstered bronze) looked clean but was restricting fuel >> flow. Flew home on other tank. >> >> 3. Bad / intermittent contact on ignition timing sensor made engine run >> rough. Landed normally and repaired. >> >> 4. Turbo hose blew off on take-off. Returned to land at reduced power. >> John >> ------ >> >> Been there, done that. (the blown-off intake hose) >> >> Also: >> I have burned out 2 turbos. The first caused precautionary/urgent landi= ng >> at an airport pending shutting off fuel flow to the turbo. The second, = I >> flipped a turbo oil shut off switch and flew 1000NM to get home. >> >> Had a fuel pump die in flight, switched to the other and kept flying.(so= ft >> failure) >> I had a bad injector enable switch causing rough running during some pha= se >> one flying (after major change)... landed normally >> >> Forgot to re-connect fuel return line in engine bay after doing some >> work. dumped a couple gallons of fuel onto the running engine until I >> smelled gas and shut down the engine.. (never left the parking space - b= ut >> it could have been really bad. >> >> Cracked alternator mount bracket found on pre-flight during phase one >> testing. Would have lost cooling and alternator if it happened now. >> >> PSRU sun gear pin broke from a backfire during run-up. Was able to taxi >> back but would not have been able to fly. >> >> This is good - broke a coolant line in flight and smelled coolant... >> landed at nearby airport and taxied up to restaurant with steam spewing = out >> of the cowl. Me and my buddy calmly walked into the restaurant and had >> breakfast. Afterward, we borrowed some tools and fixed the coolant line= . >> Went back into the restaurant to ask for 2 pitchers of water to put in o= ur >> plane. Continued ski trip to Mammoth. The end. >> >> -- >> David Leonard >> >> Turbo Rotary RV-6 N4VY >> http://N4VY.RotaryRoster.net >> http://RotaryRoster.net >> >> On Sun, Apr 12, 2009 at 2:03 PM, Mark Steitle wrot= e: >> >>> Thanks Bill, >>> >>> With the addition of Bill's exciting adventure, and one of my own, we'r= e >>> up to 18 incidents in the database. These last two, along with Ed's br= ake >>> fire, and an oil coolant rupture, totals four incidents involving fires >>> during ground operations. Hopefully, everyone carries at least one fir= e >>> extinguisher in their airplane. >>> >>> Mark S. >>> >>> On Sun, Apr 12, 2009 at 2:56 PM, Bill Schertz wro= te: >>> >>>> One other thing to watch out for -- This occurred during ground >>>> testing, but if it had happened in the air it would have been a forced >>>> landing. >>>> >>>> From my post of Feb. 8 >>>> Well, I haven't heard of this happening before -- I was ground running >>>> my engine to tune it with the EM-2 and EC-2. Ran for almost an hour,= at >>>> various rpm's to change the manifold pressure and tweak the settings. >>>> Cooling working well, I had the top cowling off to allow good exit are= a >>>> since I was tied down. Coolant pressure about 14 psi as reported on th= e >>>> EM-2. >>>> >>>> Engine was running good, took it up to ~6000 rpm swinging a 76x76 Catt= o >>>> prop, when suddenly there was steam and fluid on my windshield. Shut i= t down >>>> by killing power to the EC-2. Coolant everywhere. >>>> >>>> Got out and looked to diagnose the problem -- NOT my plumbing. A FREE= ZE >>>> PLUG in the iron housing had blown out. Rapid coolant dump. >>>> >>>> Secondary effect -- Since I shut down suddenly from full tilt, either >>>> the proximity of the cowl to the exhaust, or possibly some of the cool= ant on >>>> the exhaust started a small fire on my cowl. Put it out with extinguis= her, >>>> but corner is charred. >>>> >>>> Now in repair mode. >>>> >>>> -------------------------- >>>> Update since this incident: All freeze plugs (7) on the engine have >>>> been replaced by Bruce Turrentine, and he has inspected the engine. I = am >>>> currently reinstalling it and getting ready for more tuning exercises. >>>> >>>> Bill Schertz >>>> KIS Cruiser #4045 >>>> N343BS >>>> >>>> ----- Original Message ----- >>>> *From:* Mark Steitle >>>> *To:* Rotary motors in aircraft >>>> *Sent:* Sunday, April 12, 2009 1:51 PM >>>> *Subject:* [FlyRotary] Re: forced landings >>>> >>>> Charlie, >>>> >>>> That's a very good point. I'm trying to stay away from assigning a >>>> "cause" for whatever happened because I don't have all the facts. I h= ave a >>>> field that says "Explanation of Failure". Hopefully, we can make stat= ements >>>> as you suggest. Sometimes, even the FAA gets it wrong, like the time = they >>>> attributed the engine failure to the builder removing the oil injectio= n >>>> pump. Also, I doubt that we could all agree on a "single cause" for e= ach >>>> failure. Maybe it is due to a poor weld, or wrong choice of material,= or >>>> improper strain relief, or lack of heat shielding, or a little of each= . >>>> What I hope to accomplish is to point out areas where we need to be mo= re >>>> careful on how we design a particular part or system. >>>> >>>> List is at 16 now. Anyone else want to add a "dark and stormy night" >>>> story to the list? >>>> >>>> Mark >>>> >>>> On Sun, Apr 12, 2009 at 11:46 AM, Charlie England < >>>> ceengland@bellsouth.net> wrote: >>>> >>>>> I think that it's just as important to understand the real cause of >>>>> the failure. In the case of the plastic fuel flow sensor, it's highly >>>>> unlikely that use of the plastic sensor caused the failure; it was th= e use >>>>> of plastic in the wrong area without any protection. The homebuilder'= s >>>>> knee-jerk reaction is to say 'no plastic sensors because that one mel= ted', >>>>> even though there are tens of thousands of the same sensor in use in >>>>> boating, a much more severe environment. >>>>> >>>>> Kind of like the canard builder who tried to put fuel in a wing built >>>>> with fuel-soluble foam. Obviously, it failed, but only because of the= wrong >>>>> application of products, not the products themselves. >>>>> >>>>> Charlie >>>>> >>>>> ------------------------------ >>>>> *From:* al wick >>>>> *To:* Rotary motors in aircraft >>>>> *Sent:* Sunday, April 12, 2009 10:13:00 AM >>>>> *Subject:* [FlyRotary] Re: forced landings >>>>> >>>>> Absolutely excellent Mark. I'd encourage you to get the year the >>>>> incident occured too. That will be your proof of reduced risk from th= ings >>>>> like this newsgroup. >>>>> >>>>> Avoid the black and white approach: forced landing or not forced. >>>>> Because all things are shades of grey. Instead rate the severity. So = it's a >>>>> 10 if the guy had to glide, it's a 1 if he did precautionary landing.= If you >>>>> also explain what happened, then a reader can easily tell you were ob= jective >>>>> in your rating. >>>>> >>>>> The final piece is about how many flight hours, first flights there >>>>> were. Each year there are more engines flying, so way more likely you= will >>>>> hear of incident. A wild assed guess is ok, if you just base the gues= s on >>>>> some facts. For example, you could check faa database and find 100 pl= anes >>>>> registered with rotary engine in 2005. You can guess that equals 70 h= ours >>>>> each. Even though it's a wild assed guess, it will still be excellent >>>>> predictor of change over time. Each year you have the same "error". S= o your >>>>> numbers WILL reflect improvement. >>>>> >>>>> More important than anything. If you can force your self to say: "Tha= t >>>>> same failure will happen to me". Particularly if you can look at >>>>> "contributing factors". Then you can dramatically reduce personal ris= k. Good >>>>> example: We had that guy that installed plastic fuel flow sensor in f= uel >>>>> line. It melted, he died. Tracy just reported hot exhaust caused fuel= to >>>>> boil out of carb. These have the same root cause. You don't want to s= ay:" I >>>>> have efi, can't happen to me". You want to say:" I expect heat will c= ause a >>>>> failure. I'll put a thin ss shield here, with a bit of fibrefax glued= to >>>>> back. So if muffler fails, it won't affect....." >>>>> >>>>> Every forced landing had 10 little incidents in the past that precede= d >>>>> it. Your risk isn't some new cause. It's 1 of those 10 incidents that= you >>>>> rationalized away, instead of saying:" that will happen to me too." >>>>> >>>>> Good stuff. >>>>> >>>>> >>>>> -al wick >>>>> Cozy IV with 3.0 liter Subaru >>>>> 230+ hrs tt from Portland, Oregon >>>>> >>>>> ---------- Original Message ---------- >>>>> From: Mark Steitle >>>>> To: "Rotary motors in aircraft" >>>>> Subject: [FlyRotary] Re: Gary Casey was [FlyRotary] Re: Rotary Engine= s >>>>> Date: Sun, 12 Apr 2009 06:45:24 -0500 >>>>> >>>>> 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 o= ut >>>>> 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 in= clude >>>>> 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 f= or >>>>> improvement in the peripheral department. The good news is that out = of all >>>>> of the incidents listed above, none of them were caused by a true eng= ine >>>>> failure. That's where the rotary has really earned my respect as a v= iable >>>>> 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 br= ing you >>>>>> down. While I believe the basic rotary engine itself is more fault t= olerant >>>>>> than a recip, the peripherals used in the typical rotary install are= a lot >>>>>> more complex than a typical recip install. Since we rotary fliers do= nt have >>>>>> the benefit of 70 years worth of experience flying behind the typica= l LyCon >>>>>> farm implement I think overall our odds are considerably worse. Come= s down >>>>>> 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 go= od >>>>>> example. I may be a little sensitive to this issue since I've been t= rying 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 = noticed >>>>>> over the 10 years I have been flying my rotary powered RV-6A that th= e >>>>>> problems have decreased considerably, the success rate and completio= n rate >>>>>> has gone up and first flights are now occurring without significant = problems >>>>>> =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 m= ost >>>>>> significant thing (in my opinion) is not only does the lower part co= unt help >>>>>> reliability (if it is not there =96 it can not break), but if you lo= ok a the >>>>>> design of the eccentric shaft (for example) you notice the absence o= f the >>>>>> 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 de= sign. >>>>>> 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 ti= cking as the >>>>>> old saying goes. Only extended time and numbers will provide the tr= ue MTBF >>>>>> 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 suc= h as >>>>>> fuel and ignition frequently being one-off designs have been the cau= se of >>>>>> most failures =96 with probably fuel the prime culprit. The good ne= ws is that >>>>>> for some platforms (such as the RVs) we have pretty much established= what >>>>>> will make an installation successful. The Canard crowd is fast appr= oaching >>>>>> that status with their somewhat more challenging cooling requirement= s being >>>>>> over come. >>>>>> >>>>>> >>>>>> >>>>>> Having lost a rotor during flight due to putting in high compressi= on >>>>>> rotors with worn apex seal slots worn beyond specs (found this out l= ater =96 >>>>>> my fault for not being aware of this spec limit and checking it) whi= ch led >>>>>> 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= knob to >>>>>> full rich =96 flowing 14.5 GPH =96 a lot of it undoubtedly being bl= own 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 the >>>>>> power strokes no longer being balanced, but nothing bad and you coul= d still >>>>>> read the needles on the gauges. Other folks have had FOD damage to = a rotor >>>>>> and also make it to a safe landing. Two folks lost cooling (one los= s of >>>>>> coolant fluid , one lost of water pump) and while they did cook the = engines, >>>>>> both made it back to a safe landing. So all things considered, I th= ink the >>>>>> rotary continues to show that if the installation is designed proper= ly, 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, auxili= ary >>>>>> subsystems such as fuel and ignition frequently being one-off design= s - have >>>>>> been the cause of most failures. The good news is that for some pla= tforms >>>>>> (such as the RVs) we have pretty much established what will make an >>>>>> installation successful. The Canard crowd is fast approaching that = status >>>>>> with their somewhat more challenging cooling requirements being over= come. >>>>>> >>>>>> >>>>>> >>>>>> My rotary installation cost me $6500 back in 1996, the primary cost >>>>>> being a rebuilt engine $2000 and the PSRU $2900. I have since purch= ased a >>>>>> 1991 turbo block engine from Japan for $900 and rebuilt it myself fo= r >>>>>> another $2200. My radiators (GM evaporator cores) cost $5.00 from t= he junk >>>>>> yard and another $50.00 each for having the bungs welded on. So dep= ending >>>>>> on how much you buy and how much you build the price can vary consid= erably. >>>>>> 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,= the >>>>>> crucial thing (in my opinion) is you need to address two personal fa= ctors: >>>>>> >>>>>> >>>>>> >>>>>> 1. What is your risk tolerance? It doesn=92t really matter how sex= y >>>>>> some =93exotic=94 engine installation may seem =96 if you are not co= mfortable >>>>>> flying behind (or in front) of it, then it certainly does not makes= sense >>>>>> 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 o= f >>>>>> involvement needed. >>>>>> >>>>>> >>>>>> >>>>>> So hope you continue to contribute to expanding our knowledge and >>>>>> understanding of the rotary in its application to power plant for ai= rcraft. >>>>>> >>>>>> >>>>>> >>>>>> >>>>>> >>>>>> 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.ne= t] >>>>>> *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 c= ertainly >>>>>> 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 e= ach >>>>>> 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 ou= t, it's >>>>>> not how many parts, but the reliability of the total system that cou= nts. >>>>>> Just looking at the history of the rotary (which, from the implicat= ion of >>>>>> another post) it's not that good, but I don't think it has anything = to do >>>>>> with reliability of the concept. It's more to do with the experimen= tal >>>>>> nature of the builds and installations. My original point, perhaps = not well >>>>>> expressed is that to say there are just 4 parts is an oversimplifica= tion. >>>>>> 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 aircraf= t, and >>>>>> not just because the Columbia (can't force myself to say Cezzna :-) = was a >>>>>> derivative. Therefore, it tends to attract conservative builders an= d >>>>>> 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 failu= res in >>>>>> the ES in almost 20 years of experience. One was caused by fuel sta= rvation >>>>>> right after takeoff (fatal) and one was caused by a PSRU failure in = an auto >>>>>> engine conversion. So our old-fashioned conservative nature has ser= ved us >>>>>> pretty well. >>>>>> >>>>>> >>>>>> >>>>>> Yes, I was assuming that the rotary had electronic fuel injection an= d >>>>>> ignition, but that by itself doesn't change the inherent fuel effici= ency of >>>>>> the engine. Direct injection does have a potential to improve BSFC = because >>>>>> the fuel charge can be stratified. It will probably decrease availa= ble >>>>>> power, though. I think the best rotary will be 5% less efficient th= an the >>>>>> "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 engi= ne can >>>>>> also be so configured, but the compression ratio reduction would red= uce its >>>>>> BSFC and maybe durability advantage. The total operating cost is ce= rtainly >>>>>> significantly less if auto gas can always be used to refuel. I assu= med in >>>>>> my assessment that it will only be available 50% of the time. The r= eal >>>>>> disadvantage, which I failed to state, is that the extra fuel requir= ed for 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 th= at if >>>>>> the auto engine were equivalent in reliability to the aircraft engin= e it >>>>>> would likely cost just as much. Is the same true of the rotary? I'= 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. I would love to = do a >>>>>> rotary installation, but I don't think I could justify it by cost re= duction. >>>>>> >>>>>> >>>>>> >>>>>> It wasn't mentioned in the posts, but some have claimed the rotary i= s >>>>>> "smoother" than a recip. I at first resisted that notion. Sure, an= y rotary >>>>>> given sufficient counterbalancing, is perfectly balanced. A 4-cylin= der >>>>>> opposed recip is not - there is a significant secondary couple. The >>>>>> 6-cylinder opposed engine is perfectly balanced, but only for PRIMAR= Y and >>>>>> SECONDARY forces and couples - higher order forces have never really= been >>>>>> analyzed, although they would be very small. And then consider the = forces >>>>>> within the engine that have to be resisted by that long, heavy, but = flexible >>>>>> crankshaft. So it isn't the mechanical balance that gives the rotar= y an >>>>>> advantage. Let's take a look at the the torsional pulsations, compa= ring the >>>>>> 3-rotor against the 6-cylinder: A 6-cylinder engine has 3 power imp= ulses >>>>>> per rotation, as does the 3-rotor, so they are the same, right? Wro= ng. >>>>>> They both incorporate 4 "stroke" cycles, meaning that there separat= e and >>>>>> sequential intake, compression, power and exhaust events so that is = the same >>>>>> for both. The power event, which is the source of the torque impuls= e, takes >>>>>> 1/2 of a crank rotation for the recip. In the rotary the power even= t >>>>>> 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 exci= tation >>>>>> delivered to the propeller, PSRU and to the airframe is significantl= y less >>>>>> than for a recip. And if you analyze the actual forces imparted, th= ey go >>>>>> down by the square of the rpm. The torsional vibration amplitude go= es down >>>>>> by a factor of 4 just because the rpm of the rotary turns about twic= e as >>>>>> fast. If you've skipped to the bottom of the paragraph, as you prob= ably >>>>>> should have :-), yes the rotary is "smoother" - a LOT smoother.. (my >>>>>> apologies to rotary purists, for simplicity I used the word "cranksh= aft" 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= engine, >>>>>> but with the high vapor pressure of the fuel - it is more prone to v= apor >>>>>> lock. The fuel systems of certified aircraft are not particularly w= ell >>>>>> designed with regard to vapor lock. "Fortunately", rotary engines t= ypically >>>>>> have no mechanical fuel pump and are forced to rely on electric pump= s. >>>>>> 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 li= kely. 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 g= oing 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 = prevents >>>>>> back-feeding). Redundancy was by a "crossfeed" line that could conn= ect 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/ >>>>>> >>>>>> >>>>> >>>> >>> >> >> >> -- >> David Leonard >> >> Turbo Rotary RV-6 N4VY >> http://N4VY.RotaryRoster.net >> http://RotaryRoster.net >> > > --00163630f2df41bff7046775d3a2 Content-Type: text/html; charset=windows-1252 Content-Transfer-Encoding: quoted-printable
Mark,
=A0
Thanks for putting together this database.=A0 I agree with you and Al = G.=A0that we should keep it to issues with the engine and it's systems.= =A0 But I also agree with John and Al W. that we should somewhere include t= hings that probably would have caused an in-flight failure, especially when= found on pre-flight, run-up or take off roll.=A0 That is good stuff.=A0 No= t the idiot-pilot-owner stuff like forgetting to attach the return fuel lin= e, but the alternator bracket and PSRU issues etc - that could really help = someone.
=A0
Similarly, just because it is in flight does not make it newsworthy.= =A0 Like the intake hose blow offs that John and I have both experienced.= =A0 Sure, something happened and you are damn sure going to return to the a= irport and check it out even though you are pretty sure you know what happe= ned and it will not affect the safety of flight.=A0 OOps, didn't tighte= n that hose tight enough.
=A0
In other words, I think Johns incident #1 is far more significant than= incident #4.
=A0
Maybe to clarify:
=A0
#1 caused actual damage to the engine AND he NEEDED to land soon becau= se of oil loss.=A0 Power produced was less than normally aspirated power.= =A0 This is an interesting mechanical possibility (that a turbine blade som= ehow got BACK into the engine to bust the apex seal) and something importan= t to consider when designing a turbo install.=A0
=A0
#4 caused only a reduction=A0to normally aspirated power and a skipped= heart beat or two.=A0 No damage, no real need to land other than as a prec= aution.=A0 No design flaw or mechanical issue - just an underestimation on = how tight to make the hose clamp. (and believe me, they have to be very=A0t= ight if there is no bead under the hose.)
--
David Leonard

Turbo Rotary RV-6 N4VY
http://N4VY.RotaryRoster.net
http://RotaryRoster.net
On Mon, Apr 13, 2009 at 6:16 AM, Mark Steitle <msteitle@gmail.co= m> wrote:
Dave,
=A0
I have decided to take Al's suggestion and=A0limit=A0the criteria = for the spreadsheet to basically include any in-flight system failure which= interrupts the planned flight and results in a premature landing.=A0 Based= on this, I will add #3 & #4 as well as the one=A0resulting from=A0a ru= ptured coolant hose.=A0
=A0
Mark S.

On Mon, Apr 13, 2009 at 7:55 AM, David Leonard <= span dir=3D"ltr"><wdleonard@gmail.com> wrote:
Mark, And did you get these?=A0 Added by me and John Slade under the w= rong thread title:


On Sun, Apr 12, 2009 at 5:15 PM, John Slade <jslade@canardaviation.com>= ; wrote:

Here's a few for the list, Mark,
1. Stock turbo bearings collapse= d & took out apex seal. Flew home at reduced power.
=A0
2. Fuel f= iler (sinstered bronze) looked clean but was restricting fuel flow. Flew ho= me on other tank.
=A0
3. Bad / intermittent contact on ignition timing sensor made engine = run rough. Landed normally and repaired.
=A0
4. Turbo hose blew off o= n take-off. Returned to land at reduced power.
John
------=A0
=A0=
Been there, done that. (the blown-off intake hose)
=A0
Also:

I have burned out 2 turbos.=A0 The first caused precautionary/urgent l= anding at an airport pending shutting off fuel flow to the turbo.=A0 The se= cond, I flipped a turbo oil shut off switch and flew 1000NM to get home.
=A0
Had a fuel pump die in flight, switched to the other and kept flying.(= soft failure)
I had a bad injector enable switch causing rough running during some p= hase one flying (after major change)...=A0 landed normally=A0

Forgot to re-connect fuel return line in engine bay after doing so= me work.=A0 dumped a couple gallons of fuel onto the running engine until I= smelled gas and shut down the engine.. (never left the parking space - but= it could have been really bad.

Cracked alternator mount bracket found on pre-flight during phase = one testing.=A0 Would have lost cooling and alternator if it happened now.<= /div>

PSRU sun gear pin broke from a backfire during run-up.=A0 Was able= to taxi back but would not have been able to fly.
=A0
This is good -= broke a coolant line in flight and smelled coolant...=A0 landed at nearby = airport and taxied up to restaurant with steam spewing out of the cowl.=A0 = Me and my buddy calmly walked into the restaurant and had breakfast.=A0 Aft= erward, we borrowed some tools and fixed the coolant line.=A0 Went back int= o the restaurant to ask for 2 pitchers of water to put in our plane.=A0 Con= tinued ski trip to Mammoth.=A0 The end.

--
David Leonard

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

On Sun, Apr 12, 2009 at 2:03 PM, Mark Steitle <msteitle@gmail.com> wrote:
Thanks Bill,

With the ad= dition of Bill's exciting adventure, and one of my own, we're up to= 18 incidents in the database.=A0 These last two, along with Ed's brake= fire, and an oil coolant rupture, totals four incidents involving fires du= ring ground operations.=A0 Hopefully, everyone carries at least one fire ex= tinguisher in their airplane.

Mark S.

On Sun, Apr 12, 2009 at 2:56 PM, Bill Schertz <wschertz@comcast.net> wrote:
One other thing to watch out for -- Th= is occurred during ground testing, but if it had happened in the air it wou= ld have been a forced landing.
=A0
From=A0 my post of Feb. 8
Well, I haven't heard of this happ= ening before -- I was ground running my engine to=A0 tune it with the EM-2 = and EC-2.=A0 Ran for almost an hour, at various rpm's to change the man= ifold pressure and tweak the settings. Cooling working well, I had the top = cowling off to allow good exit area since I was tied down. Coolant pressure= about 14 psi as reported on the EM-2.
=A0
Engine was running good, took it up to= ~6000 rpm swinging a 76x76 Catto prop, when suddenly there was steam and f= luid on my windshield. Shut it down by killing power to the EC-2. Coolant e= verywhere.
=A0
Got out and looked to diagnose the pro= blem -- NOT my plumbing.=A0 A FREEZE PLUG in the iron housing had blown out= . Rapid coolant dump.
=A0
Secondary effect -- Since I shut down = suddenly from full tilt, either the proximity of the cowl to the exhaust, o= r possibly some of the coolant on the exhaust started a small fire on my co= wl. Put it out with extinguisher, but corner is charred.
=A0
Now in repair mode.
=A0
--------------------------
Update since this incident:=A0 All fre= eze plugs (7) on the engine have been replaced by Bruce Turrentine, and he = has inspected the engine. I am currently reinstalling it and getting ready = for more tuning exercises.
=A0
Bill Schertz
KIS Cruiser #4045
N343BS
----- Original Message -----
Sent: Sunday, April 12, 2009 1:51 PM
Subject: [FlyRotary] Re: forced landings

Charlie,

That's a very good point.=A0 I'm try= ing to stay away from assigning a "cause" for whatever happened b= ecause I don't have all the facts.=A0 I have a field that says "Ex= planation of Failure".=A0 Hopefully, we can make statements as you sug= gest.=A0 Sometimes, even the FAA gets it wrong, like the time they attribut= ed the engine failure to the builder removing the oil injection pump.=A0 Al= so, I doubt that we could all agree on a "single cause" for each = failure.=A0 Maybe it is due to a poor weld, or wrong choice of material, or= improper strain relief, or lack of heat shielding, or a little of each.=A0= What I hope to accomplish is to point out areas where we need to be more c= areful on how we design a particular part or system.=A0

List is at 16 now.=A0 Anyone else want to add a "dark and stormy n= ight" story to the list?=A0

Mark =A0=A0

On Sun, Apr 12, 2009 at 11:46 AM, Charlie Englan= d <ceengland@bellsouth.net> wrote:
I think that it's just as important to understand the real cause o= f the failure. In the case of the plastic fuel flow sensor, it's highly= unlikely that use of the plastic sensor caused the failure; it was the use= of plastic in the wrong area without any protection. The homebuilder's= knee-jerk reaction is to say 'no plastic sensors because that one melt= ed', even though there are tens of thousands of the same sensor in use = in boating, a much more severe environment.

Kind of like the canard builder who tried to put fuel in a wing built w= ith fuel-soluble foam. Obviously, it failed, but only because of the wrong = application of products, not the products themselves.

Charlie

From: al wick <alwick@juno.com>=20

To: Rotary motors = in aircraft <flyrotary@lancaironline.net>
Sent: Sunday, April 12, 2009 10:13:00 AM
Subject: [FlyRotary] Re: fo= rced landings

Absolutely excellent Mark. I'd encourage you to get the year the inc= ident occured too. That will be your proof of reduced risk from things like= this newsgroup.

Avoid the black and white approach: forced landing or not forced. Becaus= e all things are shades of grey. Instead rate the severity. So it's a 1= 0 if the guy had to glide, it's=A0a 1 if he did precautionary landing. = If you also explain what happened, then a reader can easily tell you were o= bjective in your rating.

The final piece is about how many flight hours, first flights there were= . Each year there are more engines flying, so way more likely you will hear= of incident. A wild assed guess is ok, if you just base the guess on some = facts. For example, you could check faa database and find 100 planes regist= ered with rotary engine in 2005. You can guess that equals 70 hours each. E= ven though it's a wild assed guess, it will still be excellent predicto= r of change over time. Each year you have the same "error". So yo= ur numbers WILL reflect improvement.

More important than anything. If you can force your self to say: "T= hat same failure will happen to me". Particularly if you can look at &= quot;contributing factors". Then you can dramatically reduce personal = risk. Good example: We had that guy that installed plastic fuel flow sensor= in fuel line. It melted, he died. Tracy just reported hot exhaust caused f= uel to boil out of carb. These have the same=A0root cause. You don't wa= nt to say:" I have efi, can't happen to me". You want to say:= " I expect heat will cause a failure. I'll put a thin ss shield he= re, with a bit of fibrefax glued to back. So if muffler fails, it won't= affect....."

Every forced landing had 10 little incidents in the past that preceded i= t. Your risk isn't some new cause. It's 1 of those 10 incidents tha= t you rationalized away, instead of saying:" that will happen to me to= o."

Good stuff.


-al wick
Cozy IV with 3.0 liter Subaru
230+ hrs tt from Portla= nd, Oregon

---------- Original Message ----------
From: Mark Stei= tle <msteitle@gm= ail.com>
To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
= Subject: [FlyRotary] Re: Gary Casey was [FlyRotary] Re: Rotary Engines
D= ate: Sun, 12 Apr 2009 06:45:24 -0500

Mike,

Has anyone ever tried to document the rotary incidents re= sulting in a forced landing?

Here's what I recall from memory, s= o 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 o= ut of spec)
=A0=A0=A0 1 forced landing due to improper assembly of engin= e (seal wedged between rotor & side housing)
=A0=A0=A0 1 forced land= ing 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 f= or continued operation at reduced power, so we may or may not wish to inclu= de those here.=A0

While a number of these incidents date back quite a few years, and we h= ave made excellent progress, it says to me that we still have room for impr= ovement in the peripheral department.=A0 The good news is that out of all o= f the incidents listed above, none of them were caused by a true engine fai= lure.=A0 That's where the rotary has really earned my respect as a viab= le a/c engine.

Pay attention to the details!

Mark S.


On Sat, Apr 11, 2009 at 9:22 PM, Mike Wills <rv-4mike= @cox.net> wrote:
This has been an interesting thread. I= n the end, it doesnt really matter how many "major" parts you hav= e - even a minor failure can bring you down. While I believe the basic rota= ry engine itself is more fault tolerant than a recip, the peripherals used = in the typical rotary install are a lot more complex than a typical recip i= nstall. Since we rotary fliers dont have the benefit of 70 years worth of e= xperience flying behind the typical LyCon farm implement I think overall ou= r odds are considerably worse. Comes down to how well an individual enginee= r's his installation and there is a tremendous amount of variation here= .
=A0
The dependence on electronics in the t= ypical rotary install=A0 is a good example. I may be a little=A0sensitive t= o this issue since I've been trying to find an intermittent glitch (2 t= imes in 22 hours of engine testing).
=A0
Mike Wills
RV-4 N144MW=A0=A0
<= /div>
----- Original Message -----
Sent: Saturday, April 11, 2009 7:31 AM
Subject: [FlyRotary] Gary Casey was [FlyRotary] Re: Rotary Engine= s

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 fl= ying my rotary powered RV-6A that the problems have decreased considerably,= the success rate and completion rate has gone up and first flights are now= occurring without significant problems =96 even cooling is OK {:>).=A0 = I believe most of this improvement can be attributed to folks sharing their= knowledge, problems and solutions with others - such as on this list.=A0 <= /span>

=A0

I know that fewer parts count is of= ten touted as one of the rotary benefit =96 and while it is true that the p= art 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 n= ot break), but if you look a the design of the eccentric shaft (for example= ) you notice the absence of the jogs in a typical crankshaft and their stre= ss points.=A0 The thing is over 3=94 in diameter at some points and does no= t have the same inertia loads born by a piston crankshaft.=A0 The parts tha= t are there are of very robust 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 and 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 promising.

=A0

Failure of rotary engines are extre= mely rare, but unfortunately, as with many alternative engine installations= , auxiliary subsystems such as fuel and ignition frequently being one-off d= esigns have been the cause of most failures =96 with probably fuel the prim= e culprit.=A0 The good news is that for some platforms (such as the RVs) we= have pretty much established what will make an installation successful.=A0= The Canard crowd is fast approaching that status with their somewhat more = challenging cooling requirements being over come.

=A0

=A0 Having lost a rotor during flig= ht 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 thi= s spec limit and checking it) which led to apex seal failure and consequenc= e lost of most of the power from one rotor, I was still able to maintain 65= 00 MSL at WOT and fuel mixture knob to full rich =96 flowing 14.5 GPH =96 a= lot of it undoubtedly =A0being blown through the disabled rotor.=A0 Flew i= t back 60 miles to a suitable runway and made a non-eventful landing.=A0=A0= There was a small increase in vibration due to the power strokes no longer= being balanced, but nothing bad and you could still read the needles on th= e gauges.=A0 Other folks 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) and while they did cook the engines, both made it back= to a safe landing.=A0 So all things considered, I think the rotary continu= es to show that if the installation is designed properly, it makes a very v= iable and reliable aircraft power plant.

=A0

Failure of rotary engines in aircra= ft are extremely rare, but unfortunately, as with many alternative engine i= nstallations, auxiliary subsystems such as fuel and ignition frequently bei= ng one-off designs - have been the cause of most failures.=A0 The good news= is that for some platforms (such as the RVs) we have pretty much establish= ed what will make an installation successful.=A0 The Canard crowd is fast a= pproaching that status with their somewhat more challenging cooling require= ments being over come.

=A0

My rotary installation cost me $650= 0 back in 1996, the primary cost being a rebuilt engine $2000 and the PSRU = $2900.=A0 I have since purchased 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 the junk yard and another $50.00 each for having th= e bungs welded on.=A0 So depending on how much you buy and how much you bui= ld the price can vary considerably.=A0 Today, I would say it would take a m= inimum of around $8000 and more nominally around $10000 for a complete rota= ry installation in an RV =96 some folks could do it for less, some for more= .

=A0

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

=A0

1.=A0 What is your risk tolerance?= =A0 It doesn=92t really matter how sexy some =93exotic=94 engine installati= on may seem =96 if you are not comfortable flying behind (or in front) of i= t, 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, exper= ience and background (and you don=92t have to be an engineer) and do you fe= el comfortable with the level of involvement needed.

=A0

So hope you continue to contribute = to expanding our knowledge and understanding of the rotary in its applicati= on to power plant for aircraft.

=A0

=A0

Best Regards

=A0

Ed

=A0

=A0

From: Rota= ry motors in aircraft [mailto:flyrotary@lancaironline.net] On Behalf Of Gary Casey
Sent: Saturday, April 11, 2= 009 8:36 AM
To: Rotary m= otors in aircraft
Subject: [FlyRotary] Re: Rotary Engines

http://www.eset.com/= =20



<= /blockquote>




--
David Leonard

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




--00163630f2df41bff7046775d3a2--