X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from mail-ew0-f167.google.com ([209.85.219.167] verified) by logan.com (CommuniGate Pro SMTP 5.2.13) with ESMTP id 3578960 for flyrotary@lancaironline.net; Mon, 13 Apr 2009 09:16:50 -0400 Received-SPF: pass receiver=logan.com; client-ip=209.85.219.167; envelope-from=msteitle@gmail.com Received: by ewy11 with SMTP id 11so3060184ewy.19 for ; Mon, 13 Apr 2009 06:16:12 -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=9Rw5lqllKvvi4rNC23YCjz14GYNepNlbZGmWBkX8k8g=; b=fBTa7YeIY1BvOCuxLP5vwTegLPCGXyXRcP8fqF5KVvHR8cDvY4S//IP9I/e3nmGHsP KFokTnqc7EW/MptNxXX0HevA3HOJUZwAeAjWefYUz7N7geJ8xAnFYPkXI3ZQKZnGkFzX XdGK4fbWifU/TkuWuMEwZzcdL1Ex+R6omxLLc= 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=mTUyXLEcU2JXz4VCBNRy8zBIZyyA88rLRbDG+JMd974ATt6j8eHqm9mFN9oz/cj3ef 1MvBC94YFscT+D0kFnkTSoqOB5hBb8TF3pwMRZdX/vB6DAvaKVlLLs4jAl8SwHztk6fs GBHE3ACp1+u/hR2pB0RrGDqaXbFhY6rncxjdo= MIME-Version: 1.0 Received: by 10.210.67.4 with SMTP id p4mr1958538eba.63.1239628572137; Mon, 13 Apr 2009 06:16:12 -0700 (PDT) In-Reply-To: References: Date: Mon, 13 Apr 2009 08:16:12 -0500 Message-ID: <5cf132c0904130616y45fd0005l63cf07b216749390@mail.gmail.com> Subject: Re: [FlyRotary] Re: forced landings From: Mark Steitle To: Rotary motors in aircraft Content-Type: multipart/alternative; boundary=0015174c3f4cb21a2404676f8415 --0015174c3f4cb21a2404676f8415 Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: quoted-printable 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 wrote: > 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 landin= g > 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.(sof= t > failure) > I had a bad injector enable switch causing rough running during some phas= e > 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 g= as > and shut down the engine.. (never left the parking space - but it could h= ave > 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 o= ut > 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 ou= r > 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 wrote= : > >> Thanks Bill, >> >> With the addition of Bill's exciting adventure, and one of my own, we're >> up to 18 incidents in the database. These last two, along with Ed's bra= ke >> fire, and an oil coolant rupture, totals four incidents involving fires >> during ground operations. Hopefully, everyone carries at least one fire >> extinguisher in their airplane. >> >> Mark S. >> >> On Sun, Apr 12, 2009 at 2:56 PM, Bill Schertz wrot= e: >> >>> 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 area >>> since I was tied down. Coolant pressure about 14 psi as reported on the >>> EM-2. >>> >>> Engine was running good, took it up to ~6000 rpm swinging a 76x76 Catto >>> prop, when suddenly there was steam and fluid on my windshield. Shut it= down >>> by killing power to the EC-2. Coolant everywhere. >>> >>> Got out and looked to diagnose the problem -- NOT my plumbing. A FREEZ= E >>> PLUG in the iron housing had blown out. Rapid coolant dump. >>> >>> Secondary effect -- Since I shut down suddenly from full tilt, either t= he >>> proximity of the cowl to the exhaust, or possibly some of the coolant o= n the >>> exhaust started a small fire on my cowl. Put it out with extinguisher, = but >>> corner is charred. >>> >>> Now in repair mode. >>> >>> -------------------------- >>> Update since this incident: All freeze plugs (7) on the engine have be= en >>> 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 ha= ve a >>> field that says "Explanation of Failure". Hopefully, we can make state= ments >>> as you suggest. Sometimes, even the FAA gets it wrong, like the time t= hey >>> attributed the engine failure to the builder removing the oil injection >>> pump. Also, I doubt that we could all agree on a "single cause" for ea= ch >>> 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 mor= e >>> 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 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 >>>> 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 thi= ngs >>>> 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 i= t'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 obj= ective >>>> 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 pla= nes >>>> registered with rotary engine in 2005. You can guess that equals 70 ho= urs >>>> 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". So= your >>>> numbers WILL reflect improvement. >>>> >>>> More important than anything. If you can force your self to say: "That >>>> same failure will happen to me". Particularly if you can look at >>>> "contributing factors". Then you can dramatically reduce personal risk= . Good >>>> example: We had that guy that installed plastic fuel flow sensor in fu= el >>>> 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 sa= y:" I >>>> have efi, can't happen to me". You want to say:" I expect heat will ca= use 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 preceded >>>> 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 Engines >>>> 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 ou= t >>>> 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 inc= lude >>>> 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 fo= r >>>> improvement in the peripheral department. The good news is that out o= f all >>>> of the incidents listed above, none of them were caused by a true engi= ne >>>> failure. That's where the rotary has really earned my respect as a vi= able >>>> 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 bri= ng you >>>>> down. While I believe the basic rotary engine itself is more fault to= lerant >>>>> 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 don= t have >>>>> the benefit of 70 years worth of experience flying behind the typical= LyCon >>>>> 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. >>>>> >>>>> The dependence on electronics in the typical rotary install is a goo= d >>>>> example. I may be a little sensitive to this issue since I've been tr= ying 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 n= oticed >>>>> over the 10 years I have been flying 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 p= roblems >>>>> =96 even cooling is OK {:>). I believe most of this improvement can = be >>>>> attributed to folks sharing their knowledge, problems and solutions w= ith >>>>> 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 mo= st >>>>> significant thing (in my opinion) is not only does the lower part cou= nt 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. The thing is o= ver 3=94 >>>>> in diameter at some points and does not have the same inertia loads b= orn by >>>>> a piston crankshaft. The parts that are there are of very robust des= ign. >>>>> 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 tic= king as the >>>>> old saying goes. Only extended time and numbers will provide the tru= e 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 such= as >>>>> fuel and ignition frequently being one-off designs have been the caus= e of >>>>> most failures =96 with probably fuel the prime culprit. The good new= s 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 appro= aching >>>>> that status with their somewhat more challenging cooling requirements= being >>>>> over come. >>>>> >>>>> >>>>> >>>>> Having lost a rotor during flight due to putting in high compressio= n >>>>> rotors with worn apex seal slots worn beyond specs (found this out la= ter =96 >>>>> my fault for not being aware of this spec limit and checking it) whic= h led >>>>> to apex seal failure and consequence lost of most of the power from o= ne >>>>> 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 blo= wn through >>>>> the disabled rotor. Flew it back 60 miles to a suitable runway and m= ade a >>>>> non-eventful landing. There was a small increase in vibration due t= o the >>>>> power strokes no longer being balanced, but nothing bad and you could= 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 loss= of >>>>> coolant fluid , one lost of water pump) and while they did cook the e= ngines, >>>>> both made it back to a safe landing. So all things considered, I thi= nk the >>>>> rotary continues to show that if the installation is designed properl= y, 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, auxilia= ry >>>>> 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 plat= forms >>>>> (such as the RVs) we have pretty much established what will make an >>>>> installation successful. The Canard crowd is fast approaching that s= tatus >>>>> 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 purcha= sed 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 th= e junk >>>>> yard and another $50.00 each for having the bungs welded on. So depe= nding >>>>> on how much you buy and how much you build the price can vary conside= rably. >>>>> 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 fac= tors: >>>>> >>>>> >>>>> >>>>> 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 com= fortable >>>>> 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=92= t >>>>> 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 air= craft. >>>>> >>>>> >>>>> >>>>> >>>>> >>>>> 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 ce= rtainly >>>>> has far more major parts. Is a valve a "major" part? I think so. I= s a >>>>> rotor corner button a major part? Not sure, but probably not. Is ea= ch >>>>> 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= , it's >>>>> not how many parts, but the reliability of the total system that coun= ts. >>>>> Just looking at the history of the rotary (which, from the implicati= on of >>>>> another post) it's not that good, but I don't think it has anything t= o do >>>>> with reliability of the concept. It's more to do with the experiment= al >>>>> nature of the builds and installations. My original point, perhaps n= ot well >>>>> expressed is that to say there are just 4 parts is an oversimplificat= ion. >>>>> But let's face it, to put in an engine that has had many thousands o= f >>>>> 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= , and >>>>> not just because the Columbia (can't force myself to say Cezzna :-) w= as 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 failur= es in >>>>> the ES in almost 20 years of experience. One was caused by fuel star= vation >>>>> right after takeoff (fatal) and one was caused by a PSRU failure in a= n auto >>>>> engine conversion. So our old-fashioned conservative nature has serv= ed 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 efficie= ncy of >>>>> the engine. Direct injection does have a potential to improve BSFC b= ecause >>>>> the fuel charge can be stratified. It will probably decrease availab= le >>>>> power, though. I think the best rotary will be 5% less efficient tha= n the >>>>> "best" piston engine(same refinements added to each). But I stated t= hat as >>>>> a simple disadvantage - as Mark pointed out, it isn't that simple. T= he >>>>> rotary already comes configured to run on auto gas. The piston engin= e can >>>>> also be so configured, but the compression ratio reduction would redu= ce its >>>>> BSFC and maybe durability advantage. The total operating cost is cer= tainly >>>>> significantly less if auto gas can always be used to refuel. I assum= ed in >>>>> my assessment that it will only be available 50% of the time. The re= al >>>>> disadvantage, which I failed to state, is that the extra fuel require= d 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 tha= t if >>>>> 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= 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 d= o a >>>>> rotary installation, but I don't think I could justify it by cost red= uction. >>>>> >>>>> >>>>> >>>>> 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= rotary >>>>> given sufficient counterbalancing, is perfectly balanced. A 4-cylind= er >>>>> opposed recip is not - there is a significant secondary couple. The >>>>> 6-cylinder opposed engine is perfectly balanced, but only for PRIMARY= and >>>>> SECONDARY forces and couples - higher order forces have never really = been >>>>> analyzed, although they would be very small. And then consider the f= orces >>>>> within the engine that have to be resisted by that long, heavy, but f= lexible >>>>> crankshaft. So it isn't the mechanical balance that gives the rotary= an >>>>> advantage. Let's take a look at the the torsional pulsations, compar= ing the >>>>> 3-rotor against the 6-cylinder: A 6-cylinder engine has 3 power impu= lses >>>>> per rotation, as does the 3-rotor, so they are the same, right? Wron= g. >>>>> They both incorporate 4 "stroke" cycles, meaning that there separate= and >>>>> sequential intake, compression, power and exhaust events so that is t= he same >>>>> for both. The power event, which is the source of the torque impulse= , takes >>>>> 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 excit= ation >>>>> delivered to the propeller, PSRU and to the airframe is significantly= less >>>>> than for a recip. And if you analyze the actual forces imparted, the= y go >>>>> down by the square of the rpm. The torsional vibration amplitude goe= s down >>>>> 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 proba= bly >>>>> should have :-), yes the rotary is "smoother" - a LOT smoother.. (my >>>>> apologies to rotary purists, for simplicity I used the word "cranksha= ft" 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 va= por >>>>> lock. The fuel systems of certified aircraft are not particularly we= ll >>>>> designed with regard to vapor lock. "Fortunately", rotary engines ty= pically >>>>> 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 t= he >>>>> aircraft and close to the fuel tanks, making vapor lock much less lik= ely. 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 go= ing to >>>>> do this I planned to put one electric pump in the wing root of each w= ing, >>>>> feeding the engine directly(the check valve in the non-running pump p= revents >>>>> back-feeding). Redundancy was by a "crossfeed" line that could conne= ct 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 > --0015174c3f4cb21a2404676f8415 Content-Type: text/html; charset=windows-1252 Content-Transfer-Encoding: quoted-printable
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

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