X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from rv-out-0506.google.com ([209.85.198.235] verified) by logan.com (CommuniGate Pro SMTP 5.2.13) with ESMTP id 3580056 for flyrotary@lancaironline.net; Mon, 13 Apr 2009 20:34:20 -0400 Received-SPF: pass receiver=logan.com; client-ip=209.85.198.235; envelope-from=fluffysheap@gmail.com Received: by rv-out-0506.google.com with SMTP id f9so2110603rvb.7 for ; Mon, 13 Apr 2009 17:33:44 -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=+rYEAvqpwCvIit8txCRdDqXWa/aDaCXPKKIF2RV+j8U=; b=BKXGEepkGqHhiVIeC3xDwajfdw5KG/1X44cdBMYQO0FjYEru51MGGgAYS7B955K2+D dSUsBP+AkW4rLmYEIq/h/qNVwNT/wCGyJUow9fICIrkdmxQHHI6BfK9Z07WizsktJJWG gaxXW8Agacfc7+VVdUnYNcE2Ms6CoWcCKuON8= 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=Z17oEgGFKI2Khbn2f6Ct6bWX1CQ5pB8dW4Wyh1CCvfGO9yBMOhIclNJpDOFyiXn0ki pj5LYoz1jpvLZRv+8QQFLxLLnB3RamH2Gu0jvN2ZLi3Z3jEdlz7JNN5ydU9QUp3aYjsy JgAeFuwE2hz/XELalIshLKumf5OstaKV6pMwI= MIME-Version: 1.0 Received: by 10.114.157.1 with SMTP id f1mr3421806wae.43.1239669223568; Mon, 13 Apr 2009 17:33:43 -0700 (PDT) In-Reply-To: References: Date: Mon, 13 Apr 2009 17:33:43 -0700 Message-ID: Subject: Re: [FlyRotary] Re: forced landings From: William Wilson To: Rotary motors in aircraft Content-Type: multipart/alternative; boundary=001636456fd6b5b7d9046778fb25 --001636456fd6b5b7d9046778fb25 Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: quoted-printable I think you just got unlucky. But... The stock water pumps are not really intended for extended high RPM operation. Racers get "underdrive pulleys" and related belts which reduce the speed at which the accessory drive belt turns. This will slow the alternator and water pump as well as anything else you have on there (if yo= u have an air pump or air conditioner). Slowing the water pump can actually improve cooling performance since it is turning much faster than it is designed to turn. I would highly recommend these. On Mon, Apr 13, 2009 at 5:14 PM, Mike Perry wrote: > Here is another to add to the list. "Water pump failure". At 18 hours = I > noticed my water pump leaking > through the weep hole. This was a slow leak that I would have to add > coolant after a two hour test flight. > Since this was the original pump on my 1986 13B I figured it was well pas= t > due considering it was 20 years > old. When I bought the new one at the Mazda dealer the parts department > said they could only get > rebuilds. > > This last Saturday at 72 hours on the engine I took off for my second tes= t > flight with a new IVO Magnum > adjustable prop. Excellent acceleration and better rate of climb than my > home made composite prop. > However, with the old prop and 2.17:1 PSRU I was never able to get much > over 5000 rpm. With the old > prop I would take off and climb to 1000 AGL then reduce power to let temp > cool down to below 200 degrees. > It would hit about 220 in the climb. Oil temps have always been below 19= 0. > > At medium pitch on the IVO I was close to 6000 rpm and by the time I > reached pattern altitude on both > the first and second flights it hit 230. On this second flight I did my > usual reduced power and let it cool > down as I flew out to my test area over the sod farms. After 15 minutes o= f > flight time I set power to 5000 rpm > and played with the prop control then worked my way up to 5500 rpm. At > this point I am 20 minutes into > the flight when I notice my temps are back at 230. I reduce power to 400= 0 > rpm and check oil temp is > still at 180-190. I turned back to the airport but the temp is still > climbing. Reduced power to 3500 and about > 90 knots. GPS says 10 minute ETE and now the oil temp is at 200. > > I got a straight in to Rwy 33 and when I cut the power on final I had 260 > on the water pump outlet sensor, > which was probably just reading hot air and 230 on the pump inlet sensor. > Oil temp hit a hi of 230. The engine > never missed a beat the whole time. When I got off the runway and shut i= t > down I had a trail of coolant > behind me. I pulled the cowl off and had coolant all over the bottom cow= l > where my over flow tube dumps out > but no sign of hose or fitting failures. Sunday after letting it cool > overnight I swung the prop through and it still > has good compression from the sound of it. I started to fill up my > expansion tank and after about 2 quarts of > coolant I could hear it draining back into my drip pan. The coolant was > just running out the weep hole on the > water pump. > > I would like to know if anyone else has had problems with water pumps and > any comments. > > Mike Perry > N981MP > Long Ez > > http://www.tohoflyer.com/ > > > > > ----- Original Message ----- > *From:* Mark Steitle > *To:* Rotary motors in aircraft > *Sent:* Monday, April 13, 2009 9:16 AM > *Subject:* [FlyRotary] Re: forced landings > > 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 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 >> > > ------------------------------ > > > No virus found in this incoming message. > Checked by AVG - www.avg.com > Version: 8.0.238 / Virus Database: 270.11.54/2056 - Release Date: 04/13/0= 9 > 05:51:00 > > --001636456fd6b5b7d9046778fb25 Content-Type: text/html; charset=windows-1252 Content-Transfer-Encoding: quoted-printable I think you just got unlucky.=A0 But...

The stock water pumps are no= t really intended for extended high RPM operation.=A0 Racers get "unde= rdrive pulleys" and related belts which reduce the speed at which the = accessory drive belt turns.=A0 This will slow the alternator and water pump= as well as anything else you have on there (if you have an air pump or air= conditioner).=A0 Slowing the water pump can actually improve cooling perfo= rmance since it is turning much faster than it is designed to turn.=A0 I wo= uld highly recommend these.

On Mon, Apr 13, 2009 at 5:14 PM, Mike Perry = <MKPerry99@cfl= .rr.com> wrote:
Here is another to add to the list.=A0= "Water=20 pump failure".=A0 At 18 hours I noticed my water pump leaking
through the weep hole.=A0 This was a s= low leak=20 that I would have to add coolant after a two hour test flight.
Since this was the original pump on my= 1986 13B I=20 figured it was well past due considering it was 20 years
old.=A0 When I bought the new one at t= he Mazda=20 dealer the parts department said they could only get
rebuilds.
=A0
This last Saturday at 72 hours on the = engine I took=20 off for my second test flight with a new IVO Magnum
adjustable prop.=A0 Excellent accelera= tion and=20 better rate of climb than my home made composite prop.
However, with the old prop and 2.17:1 = PSRU I was=20 never able to get much over 5000 rpm. With the old
prop I would take off and climb to 100= 0 AGL then=20 reduce power to let temp cool down to below 200 degrees.
It would hit about 220 in the climb.= =A0 Oil=20 temps have always been below 190.
=A0
At medium pitch on the IVO I was close= to 6000 rpm=20 and by the time I reached pattern altitude on both
the first and second flights it hit 23= 0.=A0 On=20 this second flight I did my usual reduced power and let=A0it=20 cool
down as I flew out to my test area ove= r the sod=20 farms. After 15 minutes of flight time I set power to 5000 rpm
and played with the prop control then = worked my way=20 up to 5500 rpm.=A0 At this point I am 20 minutes into
the flight when I notice my temps are = back at=20 230.=A0 I reduce power to 4000 rpm and check oil temp is
still at 180-190.=A0 I turned back to = the=20 airport=A0but the temp is still climbing.=A0 Reduced power to 3500 and=20 about
90 knots.=A0 GPS says 10 minute ETE an= d now the=20 oil temp is at 200.=A0
=A0
I got a straight in to Rwy 33 and when= I cut the=20 power on final I had 260 on the water pump outlet sensor,
which was probably just reading hot ai= r and 230 on=20 the pump inlet sensor. Oil temp hit a hi of 230.=A0 The engine
never missed a beat the whole time.=A0= When I=20 got off the runway and shut it down I had a trail of coolant
behind me.=A0 I pulled the cowl off an= d had=20 coolant all over the bottom cowl where my over flow tube dumps out
but no sign of hose or fitting failure= s.=A0=20 Sunday after letting it cool overnight I swung the prop through and it=20 still
has good compression from the sound of= it.=A0 I=20 started to fill up my expansion tank and after about 2 quarts of
coolant I could hear it draining back = into my drip=20 pan.=A0 The coolant was just running out the weep hole on the
water pump.
=A0
I would like to know if anyone else ha= s=20 had=A0problems with water pumps=A0and any comments.
=A0
Mike Perry
N981MP
Long Ez
=A0
=A0
=A0
=A0
----- Original Message -----
From:=20 Mark Steitle=20
Sent: Mond= ay, April 13, 2009 9:16=20 AM
Subject: [FlyRotary] Re: forced=20 landings

Dave,
=A0
I have decided to take Al's suggestion and=A0limit=A0the criteri= a=20 for the spreadsheet to basically include any in-flight system failure whi= ch=20 interrupts the planned flight and results in a premature landing.=A0 Base= d=20 on this, I will add #3 & #4 as well as the one=A0resulting from=A0a= =20 ruptured coolant hose.=A0
=A0
Mark S.

= On Mon, Apr 13, 2009 at 7:55 AM, David Leonard <wdleonard@gmail.com&= gt;=20 wrote:
Mark, And did you get these?=A0 Added by me and John Slade under t= he=20 wrong 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 coll= apsed=20 & took out apex seal. Flew home at reduced power.
=A0
2. Fuel= =20 filer (sinstered bronze) looked clean but was restricting fuel flow. Fl= ew=20 home on other tank.
=A0
3. Bad / intermittent contact on ignition= =20 timing sensor made engine run rough. Landed normally and=20 repaired.
=A0
4. Turbo hose blew off on take-off. Returned to lan= d=20 at reduced power.
John
------=A0
=A0
Been there, done=20 that. (the blown-off intake hose)
=A0
Also:

I have burned out 2 turbos.=A0 The first caused precautionary/urge= nt=20 landing at an airport pending shutting off fuel flow to the turbo.=A0 T= he=20 second, I flipped a turbo oil shut off switch and flew 1000NM to get=20 home.
=A0
Had a fuel pump die in flight, switched to the other and kept=20 flying.(soft failure)
I had a bad injector enable switch causing rough running during so= me=20 phase one flying (after major change)...=A0 landed normally=A0

Forgot to re-connect fuel return line in engine bay after doin= g=20 some work.=A0 dumped a couple gallons of fuel onto the running engine= =20 until I smelled gas and shut down the engine.. (never left the parking = space=20 - but it could have been really bad.

Cracked alternator mount bracket found on pre-flight during ph= ase=20 one testing.=A0 Would have lost cooling and alternator if it happened= =20 now.
On Sun, Apr 12, 2009 at 2:= 03 PM, Mark Steitle <msteitle@gmail.com> wrote:
Thanks=20 Bill,

With the addition of Bill's exciting adventure, and= one of=20 my own, we're up to 18 incidents in the database.=A0 These last t= wo,=20 along with Ed's brake fire, and an oil coolant rupture, totals fo= ur=20 incidents involving fires during ground operations.=A0 Hopefully,=20 everyone carries at least one fire extinguisher in their=20 airplane.

Mark S.

On Sun, Apr 12, 2009 at = 2:56 PM, Bill Schertz <wschertz@comcast.net> wrote:
One other thing to watch out f= or -- This=20 occurred during ground testing, but if it had happened in the air i= t=20 would have been a forced landing.
=A0
From=A0 my post of Feb. 8
Well, I haven't heard of t= his happening=20 before -- I was ground running my engine to=A0 tune it with the EM-= 2=20 and EC-2.=A0 Ran for almost an hour, at various rpm's to change= the=20 manifold pressure and tweak the settings. Cooling working well, I h= ad=20 the top cowling off to allow good exit area since I was tied down.= =20 Coolant pressure about 14 psi as reported on the EM-2.
=A0
Engine was running good, took = it up to=20 ~6000 rpm swinging a 76x76 Catto prop, when suddenly there was stea= m and=20 fluid on my windshield. Shut it down by killing power to the EC-2.= =20 Coolant everywhere.
=A0
Got out and looked to diagnose= the problem=20 -- NOT my plumbing.=A0 A FREEZE PLUG in the iron housing had blown= =20 out. Rapid coolant dump.
=A0
Secondary effect -- Since I sh= ut down=20 suddenly from full tilt, either the proximity of the cowl to the=20 exhaust, or possibly some of the coolant on the exhaust started a s= mall=20 fire on my cowl. Put it out with extinguisher, but corner is=20 charred.
=A0
Now in repair mode.
=A0
--------------------------
Update since this incident:=A0= All=20 freeze plugs (7) on the engine have been replaced by Bruce Turrenti= ne,=20 and he has inspected the engine. I am currently reinstalling it and= =20 getting ready for more tuning exercises.
=A0
Bill Schertz
KIS Cruiser #4045
N343BS
<= div class=3D"im">
-----=20 Original Message -----
From:=20 Mark Steitle
Sent:=20 Sunday, April 12, 2009 1:51 PM
Subject:=20 [FlyRotary] Re: forced landings

Charlie,

That's= a very good point.=A0 I'm=20 trying to stay away from assigning a "cause" for whatev= er happened=20 because I don't have all the facts.=A0 I have a field that sa= ys=20 "Explanation of Failure".=A0 Hopefully, we can make sta= tements as=20 you suggest.=A0 Sometimes, even the FAA gets it wrong, like the= =20 time they attributed the engine failure to the builder removing t= he=20 oil injection pump.=A0 Also, I doubt that we could all agree on a= =20 "single cause" for each failure.=A0 Maybe it is due to = a poor weld,=20 or wrong choice of material, or improper strain relief, or lack o= f=20 heat shielding, or a little of each.=A0 What I hope to accomplish= =20 is to point out areas where we need to be more careful on how we= =20 design a particular part or system.=A0

List is at 16=20 now.=A0 Anyone else want to add a "dark and stormy night&quo= t; story to=20 the list?=A0

Mark =A0=A0

On Sun, Apr 12= , 2009 at 11:46 AM, Charlie=20 England <ceengland@bellsouth.net> wrote:
I think that it's just as important to understand the = real=20 cause of the failure. In the case of the plastic fuel flow sens= or,=20 it's highly unlikely that use of the plastic sensor caused = the=20 failure; it was the use of plastic in the wrong area without an= y=20 protection. The homebuilder's knee-jerk reaction is to say = 'no=20 plastic sensors because that one melted', even though there= are tens=20 of thousands of the same sensor in use in boating, a much more= =20 severe environment.


Kind of like the c= anard builder who tried=20 to put fuel in a wing built with fuel-soluble foam. Obviously, = it=20 failed, but only because of the wrong application of products, = not=20 the products themselves.

Charlie

From: al wick = <alwick@juno.com>=20 Sent: Sunday, April 12, 2009=20 10:13:00 AM
Subject: [FlyRotary] Re: forced=20 landings

Absolutely excellent Mark. I'd encourage you to get the = year the=20 incident occured too. That will be your proof of reduced risk f= rom=20 things like this newsgroup.

Avoid the black and white approach: forced landing or not fo= rced.=20 Because all things are shades of grey. Instead rate the severit= y. So=20 it's a 10 if the guy had to glide, it's=A0a 1 if he did= =20 precautionary landing. If you also explain what happened, then = a=20 reader can easily tell you were objective in your rating.

The final piece is about how many flight hours, first flight= s=20 there were. Each year there are more engines flying, so way mor= e=20 likely you will hear of incident. A wild assed guess is ok, if = you=20 just base the guess on some facts. For example, you could check= faa=20 database and find 100 planes registered with rotary engine in 2= 005.=20 You can guess that equals 70 hours each. Even though it's a= wild=20 assed guess, it will still be excellent predictor of change ove= r=20 time. Each year you have the same "error". So your nu= mbers WILL=20 reflect improvement.

More important than anything. If you can force your self to = say:=20 "That same failure will happen to me". Particularly i= f you can look=20 at "contributing factors". Then you can dramatically = reduce personal=20 risk. Good example: We had that guy that installed plastic fuel= flow=20 sensor in fuel line. It melted, he died. Tracy just reported ho= t=20 exhaust caused fuel to boil out of carb. These have the=20 same=A0root cause. You don't want to say:" I have efi,= can't=20 happen to me". You want to say:" I expect heat will c= ause a failure.=20 I'll put a thin ss shield here, with a bit of fibrefax glue= d to=20 back. So if muffler fails, it won't affect....."

Every forced landing had 10 little incidents in the past tha= t=20 preceded it. Your risk isn't some new cause. It's 1 of = those 10=20 incidents that you rationalized away, instead of saying:" = that will=20 happen to me too."

Good stuff.


-al wick
Cozy IV with 3.0= liter Subaru
230+ hrs tt from=20 Portland, Oregon

---------- Original Message=20 ----------
From: Mark Steitle <msteitle@gmail.com>
To: "Rotar= y motors in=20 aircraft" <flyrotary@lancaironline.net>
Subject:=20 [FlyRotary] Re: Gary Casey was [FlyRotary] Re: Rotary=20 Engines
Date: Sun, 12 Apr 2009 06:45:24 -0500

Mike,= =20

Has anyone ever tried to document the rotary incidents= =20 resulting in a forced landing?

Here's what I recall = from=20 memory, so it likely is missing a=20 few;
=A0
=A0=A0=A0 3 forced landings due to=20 ruptured oil coolers
=A0=A0=A0 1 forced landing due to=20 apex seal coming out of its slot (rotor out of=20 spec)
=A0=A0=A0 1 forced landing due to improper=20 assembly of engine (seal wedged between rotor & side=20 housing)
=A0=A0=A0 1 forced landing on highway due to=20 catastrophic overheating of engine
=A0=A0=A0 2 forced=20 landings (one fatal) due to probable fuel system design flaw=A0= =20
=A0=A0=A0 1 forced landing on highway due to ingestion=20 of FOD.=A0

There were a few others, such as turbo=20 failures which allowed for continued operation at reduced power= , so=20 we may or may not wish to include those here.=A0

While = a=20 number of these incidents date back quite a few years, and we h= ave=20 made excellent progress, it says to me that we still have room = for=20 improvement in the peripheral department.=A0 The good news is= =20 that out of all of the incidents listed above, none of them wer= e=20 caused by a true engine failure.=A0 That's where the rotary= has=20 really earned my respect as a viable a/c engine.

Pay=20 attention to the details!

Mark S.=20


On Sat, Apr 11, 2009 at 9:22 PM, Mike Wills <rv-4mike@cox.net> wrote:
This has been an interes= ting thread.=20 In the end, it doesnt really matter how many "major"= ; parts you=20 have - even a minor failure can bring you down. While I belie= ve=20 the basic rotary engine itself is more fault tolerant than a= =20 recip, the peripherals used in the typical rotary install are= a=20 lot more complex than a typical recip install. Since we rotar= y=20 fliers dont have the benefit of 70 years worth of experience= =20 flying behind the typical LyCon farm implement I think overal= l our=20 odds are considerably worse. Comes down to how well an indivi= dual=20 engineer's his installation and there is a tremendous amo= unt of=20 variation here.
=A0
The dependence on electr= onics in the=20 typical rotary install=A0 is a good example. I may be a=20 little=A0sensitive to this issue since I've been trying t= o find=20 an intermittent glitch (2 times in 22 hours of engine=20 testing).
=A0
Mike Wills
RV-4=20 N144MW=A0=A0
-----=20 Original Message -----
Sent:=20 Saturday, April 11, 2009 7:31 AM
Subject:=20 [FlyRotary] Gary Casey was [FlyRotary] Re: Rotary Engines

Good=20 analysis and logic, Gary.

=A0<= /p>

You=92d=20 make a good addition to the =93rotary community=94.=A0 I ha= ve=20 noticed over the 10 years I have been flying my rotary powe= red=20 RV-6A that the problems have decreased considerably, the su= ccess=20 rate and completion rate has gone up and first flights are = now=20 occurring without significant problems =96 even cooling is = OK=20 {:>).=A0 I believe most of this improvement can be=20 attributed to folks sharing their knowledge, problems and= =20 solutions with others - such as on this list.=A0=20

=A0<= /p>

I know= =20 that fewer parts count is often touted as one of the rotary= =20 benefit =96 and while it is true that the part count is low= er, the=20 most significant thing (in my opinion) is not only does the= =20 lower part count help reliability (if it is not there =96 i= t can=20 not break), but if you look a the design of the eccentric s= haft=20 (for example) you notice the absence of the jogs in a typic= al=20 crankshaft and their stress points.=A0 The thing is over 3= =94=20 in diameter at some points and does not have the same inert= ia=20 loads born by a piston crankshaft.=A0 The parts that are=20 there are of very robust design.=A0 Finally, the rotary is = (I=20 believe) more tolerant of damage and tends to fail =93gradu= ally=20 and gracefully=94, it can take a licking and keep on tickin= g as=20 the old saying goes.=A0 Only extended time and numbers will= =20 provide the true MTBF for the rotary, but I believe it look= s=20 very promising.

=A0<= /p>

Failure=20 of rotary engines are extremely rare, but unfortunately, as= with=20 many alternative engine installations, auxiliary subsystems= such=20 as fuel and ignition frequently being one-off designs have = been=20 the cause of most failures =96 with probably fuel the prime= =20 culprit.=A0 The good news is that for some platforms (such = as=20 the RVs) we have pretty much established what will make an= =20 installation successful.=A0 The Canard crowd is fast=20 approaching that status with their somewhat more challengin= g=20 cooling requirements being over come.

=A0<= /p>

=A0=20 Having lost a rotor during flight due to putting in high=20 compression rotors with worn apex seal slots worn beyond sp= ecs=20 (found this out later =96 my fault for not being aware of t= his=20 spec limit and checking it) which led to apex seal failure = and=20 consequence lost of most of the power from one rotor, I was= =20 still able to maintain 6500 MSL at WOT and fuel mixture kno= b to=20 full rich =96 flowing 14.5 GPH =96 a lot of it undoubtedly= =20 =A0being blown through the disabled rotor.=A0 Flew it back= =20 60 miles to a suitable runway and made a non-eventful=20 landing.=A0=A0 There was a small increase in vibration due= =20 to the power strokes no longer being balanced, but nothing = bad=20 and you could still read the needles on the gauges.=A0 Othe= r=20 folks have had FOD damage to a rotor and also make it to a = safe=20 landing.=A0 Two folks lost cooling (one loss of coolant flu= id=20 , one lost of water pump) and while they did cook the engin= es,=20 both made it back to a safe landing.=A0 So all things=20 considered, I think the rotary continues to show that if th= e=20 installation is designed properly, it makes a very viable a= nd=20 reliable aircraft power plant.

=A0<= /p>

Failure=20 of rotary engines in aircraft are extremely rare, but=20 unfortunately, as with many alternative engine installation= s,=20 auxiliary subsystems such as fuel and ignition frequently b= eing=20 one-off designs - have been the cause of most failures.=A0= =20 The good news is that for some platforms (such as the RVs) = we=20 have pretty much established what will make an installation= =20 successful.=A0 The Canard crowd is fast approaching that=20 status with their somewhat more challenging cooling require= ments=20 being over come.

=A0<= /p>

My=20 rotary installation cost me $6500 back in 1996, the primary= cost=20 being a rebuilt engine $2000 and the PSRU $2900.=A0 I have= =20 since purchased a 1991 turbo block engine from Japan for $9= 00=20 and rebuilt it myself for another $2200. =A0My radiators (G= M=20 evaporator cores) cost $5.00 from the junk yard and another= =20 $50.00 each for having the bungs welded on.=A0 So depending= =20 on how much you buy and how much you build the price can va= ry=20 considerably.=A0 Today, I would say it would take a minimum= =20 of around $8000 and more nominally around $10000 for a comp= lete=20 rotary installation in an RV =96 some folks could do it for= less,=20 some for more.

=A0<= /p>

But,=20 regardless of the technical merit (or not) in someone=92s m= ind,=20 the crucial thing (in my opinion) is you need to address tw= o=20 personal factors:

=A0<= /p>

1.=A0=20 What is your risk tolerance?=A0 It doesn=92t really matter = how=20 sexy some =93exotic=94 engine installation may seem =96 if = you are not=20 comfortable flying behind (or in front) of it, then it cert= ainly=20 does not =A0makes sense to go that route.=A0 After all,=20 this is supposed to have an element of fun and enjoyment to= =20 it.

=A0<= /p>

2.=A0=20 What is your knowledge, experience and background (and you = don=92t=20 have to be an engineer) and do you feel comfortable with th= e=20 level of involvement needed.

=A0<= /p>

So hope=20 you continue to contribute to expanding our knowledge and= =20 understanding of the rotary in its application to power pla= nt=20 for aircraft.

=A0<= /p>

=A0<= /p>

Best=20 Regards

=A0<= /p>

Ed

=A0<= /p>

=A0<= /p>

From: Rotary motors in=20 aircraft [mailto:flyrotary@lancaironline.net]=20 On Behalf Of <= /b>Gary=20 Casey
Sent:= =20 Saturday, April 11, 2009 8:36 AM
To: Rotary motors in=20 aircraft
Subject:<= /span> [FlyRotary] Re:=20 Rotary Engines

=A0

Just to add a few more comments and=20 answers to the several excellent comments=20 posted:

=A0

How many parts does it take to make a=20 rotary rotate? =A0Well, "parts aren't parts" = in this case.=20 =A0Mark was right in that there are maybe 4 "major&quo= t;=20 components, but you have to define major. =A0A piston engin= e=20 certainly has far more major parts. =A0Is a valve a "m= ajor"=20 part? =A0I think so. =A0Is a rotor corner button a major=20 part? =A0Not sure, but probably not. =A0Is each planet=20 gear in the PSRU a major part? =A0I say yes, and the PSRU i= s=20 an integral part of the rotary engine. =A0As someone=20 correctly pointed out, it's not how many parts, but the= =20 reliability of the total system that counts. =A0Just lookin= g=20 at the history of the rotary (which, from the implication o= f=20 another post) it's not that good, but I don't think= it has=20 anything to do with reliability of the concept. =A0It's= more=20 to do with the experimental nature of the builds and=20 installations. =A0My original point, perhaps not well=20 expressed is that to say there are just 4 parts is an=20 oversimplification. =A0But let's face it, to put in an = engine=20 that has had many thousands of identical predecessors is le= ss=20 "experimental" than one that hasn't..<= /font>

=A0

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

=A0

Yes, I was assuming that the rotary had=20 electronic fuel injection and ignition, but that by itself= =20 doesn't change the inherent fuel efficiency of the engi= ne.=20 =A0Direct injection does have a potential to improve BSFC= =20 because the fuel charge can be stratified. =A0It will=20 probably decrease available power, though. =A0I think the= =20 best rotary will be 5% less efficient than the "best&q= uot; piston=20 engine(same refinements added to each). =A0But I stated tha= t=20 as a simple disadvantage - as Mark pointed out, it isn'= t that=20 simple. =A0The rotary already comes configured to run on au= to=20 gas. =A0The piston engine can also be so configured, but th= e=20 compression ratio reduction would reduce its BSFC and maybe= =20 durability advantage. =A0The total operating cost is=20 certainly significantly less if auto gas can always be used= to=20 refuel. =A0I assumed in my assessment that it will only be= =20 available 50% of the time. =A0The real disadvantage, which = I=20 failed to state, is that the extra fuel required for a give= n=20 mission might be 5 or 10% higher and that negated the weigh= t=20 advantage, if only for long-range=20 flights.

=A0

Is the engine less expensive? =A0I=20 did a thorough analysis of a direct-drive recip auto engine= =20 installation and my conclusion was that if the auto engine = were=20 equivalent in reliability to the aircraft engine it would l= ikely=20 cost just as much. =A0Is the same true of the rotary?=20 =A0I'm not sure, but you have to consider the total cos= t,=20 including engineering of all the parts in the system, not j= ust=20 the core engine. =A0I would love to do a rotary installatio= n,=20 but I don't think I could justify it by cost=20 reduction.

=A0

It wasn't mentioned in the posts, but=20 some have claimed the rotary is "smoother" than a= recip. =A0I=20 at first resisted that notion. =A0Sure, any rotary given=20 sufficient counterbalancing, is perfectly balanced. =A0A=20 4-cylinder opposed recip is not - there is a significant=20 secondary couple. =A0The 6-cylinder opposed engine is=20 perfectly balanced, but only for PRIMARY and SECONDARY forc= es=20 and couples - higher order forces have never really been=20 analyzed, although they would be very small. =A0And then=20 consider the forces within the engine that have to be resis= ted=20 by that long, heavy, but flexible crankshaft. =A0So it isn&= #39;t=20 the mechanical balance that gives the rotary an advantage.= =20 =A0Let's take a look at the the torsional pulsations,= =20 comparing the 3-rotor against the 6-cylinder: =A0A 6-cylind= er=20 engine has 3 power impulses per rotation, as does the 3-rot= or,=20 so they are the same, right? =A0Wrong. =A0They both=20 incorporate 4 "stroke" cycles, meaning that there= separate and=20 sequential intake, compression, power and exhaust events so= that=20 is the same for both. =A0The power event, which is the sour= ce=20 of the torque impulse,=A0takes 1/2 of a crank rotation for= =20 the recip. =A0In the rotary the power event requires 1/4 of= a=20 ROTOR rotation, but the rotor rotates at 1/3 crank rotation= -=20 the result is that the power impulse lasts 3/4 of a CRANK= =20 rotation, 50% longer than in a recip. =A0Therefore, the=20 torsional excitation delivered to the propeller, PSRU and t= o the=20 airframe is significantly less than for a recip. =A0And if= =20 you analyze the actual forces imparted, they go down by the= =20 square of the rpm. =A0The torsional vibration amplitude goe= s=20 down by a factor of 4 just because the rpm of the rotary tu= rns=20 about twice as fast. =A0If you've skipped to the bottom= of=20 the paragraph, as you probably should have :-), yes the rot= ary=20 is "smoother" - a LOT smoother.. (my apologies to= rotary=20 purists, for simplicity I used the word "crankshaft&qu= ot; for both=20 engines)

=A0

But just because you can burn auto gas=20 should you? =A0The biggest problems with auto gas in recip= =20 aircraft have nothing to do with the engine, but with the h= igh=20 vapor pressure of the fuel - it is more prone to vapor lock= .=20 =A0The fuel systems of certified aircraft are not=20 particularly well designed with regard to vapor lock.=20 =A0"Fortunately", rotary engines typically have n= o mechanical=20 fuel pump and are forced to rely on electric pumps.=20 =A0Fortunately because the pumps can be located at the very= =20 bottom of the aircraft and close to the fuel tanks, making = vapor=20 lock much less likely. =A0I would caution any builders to= =20 consider vapor lock possibilities very seriously, much more= so=20 if you intend to run auto gas. =A0when I was going to do th= is=20 I planned to put one electric pump in the wing root of each= =20 wing, feeding the engine directly(the check valve in the=20 non-running pump prevents back-feeding). =A0Redundancy was = by=20 a "crossfeed" line that could connect the tanks= =20 together.

=A0

And thanks, Mark for - probably=20 incorrectly - referring to me as a "good engineer"= ;. =A0I'll=20 have to put that in my resume!

=A0

Have a good day,

Gary

(do you allow us outsiders in your=20 events? =A0I'll park well away :-)

=A0




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--
David Leonard

Turbo Rotary RV-6 N4V= Y
http://N4V= Y.RotaryRoster.net
http://RotaryRoster.net


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