X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from imr-d03.mx.aol.com ([205.188.157.41] verified) by logan.com (CommuniGate Pro SMTP 5.2.13) with ESMTP id 3580860 for flyrotary@lancaironline.net; Tue, 14 Apr 2009 14:17:40 -0400 Received-SPF: pass receiver=logan.com; client-ip=205.188.157.41; envelope-from=WRJJRS@aol.com Received: from imo-da01.mx.aol.com (imo-da01.mx.aol.com [205.188.169.199]) by imr-d03.mx.aol.com (v107.10) with ESMTP id RELAYIN4-549e4d28d1fb; Tue, 14 Apr 2009 14:14:37 -0400 Received: from WRJJRS@aol.com by imo-da01.mx.aol.com (mail_out_v40_r1.5.) id q.bc6.41cb4bd2 (37034) for ; Tue, 14 Apr 2009 14:14:20 -0400 (EDT) Received: from smtprly-ma01.mx.aol.com (smtprly-ma01.mx.aol.com [64.12.207.140]) by cia-db02.mx.aol.com (v123.3) with ESMTP id MAILCIADB024-5c4349e4d272304; Tue, 14 Apr 2009 14:14:19 -0400 Received: from FWM-D40 (fwm-d40.webmail.aol.com [205.188.162.16]) by smtprly-ma01.mx.aol.com (v123.3) with ESMTP id MAILSMTPRLYMA011-5c4349e4d272304; Tue, 14 Apr 2009 14:14:10 -0400 References: To: flyrotary@lancaironline.net Subject: Re: [FlyRotary] Re: forced landings Date: Tue, 14 Apr 2009 14:14:10 -0400 X-AOL-IP: 205.188.169.199 In-Reply-To: X-MB-Message-Source: WebUI MIME-Version: 1.0 From: wrjjrs@aol.com X-MB-Message-Type: User Content-Type: multipart/alternative; boundary="--------MB_8CB8B43F1316CE0_96C_1CD6_FWM-D40.sysops.aol.com" X-Mailer: AOL Webmail 42402-STANDARD Received: from 66.253.96.220 by FWM-D40.sysops.aol.com (205.188.162.16) with HTTP (WebMailUI); Tue, 14 Apr 2009 14:14:10 -0400 Message-Id: <8CB8B43F0E78476-96C-E58@FWM-D40.sysops.aol.com> X-Spam-Flag:NO ----------MB_8CB8B43F1316CE0_96C_1CD6_FWM-D40.sysops.aol.com Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Something to note guys the EG/water mix keeps the seal lubed. If you run= plain water (it cools better) get some=C2=A0RedLine water wetter, it has= a seal lube in it. Evans is also supposed to be goodd for the seal. FWIW. Bill Jepson=C2=A0 -----Original Message----- From: Ed Anderson To: Rotary motors in aircraft Sent: Mon, 13 Apr 2009 5:46 pm Subject: [FlyRotary] Re: forced landings Mike, I agree with William =E2=80=93 Probably =C2=A0just unlucky.=C2=A0 I= have flow with a 86 water pump for over 10 years including over heating,= coolant pressure up to 23 psi (or higher) and the old pump just keeps goi= ng strong.=C2=A0 So I moved it from my 86 N/A engine to my 91 turbo block= (I have JCN threads cut into the pump intake =E2=80=93 so I can thread an= AN-16 fitting into it). =C2=A0 I also have a racing beat =E2=80=9Cunderdrive=E2=80=9D main pulley which= slows down the water pump rpm.=C2=A0 I also have one on my alternator (al= so over 10 years of flying). =C2=A0 OR the rebuild joy on your water pump may just not have been up to snuff. =C2=A0 Ed =C2=A0 Ed Anderson Rv-6A N494BW Rotary Powered Matthews, NC eanderson@carolina.rr.com http://www.andersonee.com http://www.dmack.net/mazda/index.html 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 Be= half Of William Wilson Sent: Monday, April 13, 2009 8:3 4 PM To: Rotary motors in aircraft Subject: [FlyRotary] Re: forced landings =C2=A0 I think you just got unlucky.=C2=A0 But... The stock water pumps are not really intended for extended high RPM operat= ion.=C2=A0 Racers get "underdrive pulleys" and related belts which reduce= the speed at which the accessory drive belt turns.=C2=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).=C2=A0 Slowing the water pum= p can actually improve cooling performance since it is turning much faster= than it is designed to turn.=C2=A0 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.=C2=A0 "Water pump failure".=C2=A0 At= 18 hours I noticed my water pump leaking through the weep hole.=C2=A0 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 past= due considering it was 20 years old.=C2=A0 When I bought the new one at the Mazda dealer the parts departm= ent said they could only get rebuilds. =C2=A0 This last Saturday at 72 hours on the engine I took off for my second test= flight with a new IVO Magnum adjustable prop.=C2=A0 Excellent acceleration and better rate of climb tha= n my home made composite prop. However, with the old prop and 2.17:1 PSRU I was never able to get much o ver 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.=C2=A0 Oil temps have always been belo= w 190. =C2=A0 At medium pitch on the IVO I was close to 6000 rpm and by the time I reach= ed pattern altitude on both the first and second flights it hit 230.=C2=A0 On this second flight I did= my usual reduced power and let=C2=A0it cool down as I flew out to my test area over the sod farms. After 15 minutes of= flight time I set power to 5000 rpm and played with the prop control then worked my way up to 5500 rpm.=C2=A0= At this point I am 20 minutes into the flight when I notice my temps are back at 230.=C2=A0 I reduce power to= 4000 rpm and check oil temp is still at 180-190.=C2=A0 I turned back to the airport=C2=A0but the temp is= still climbing.=C2=A0 Reduced power to 3500 and about 90 knots.=C2=A0 GPS says 10 minute ETE and now the oil temp is at 200.=C2= =A0 =C2=A0 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.=C2=A0 The engine never missed a beat the whole time.=C2=A0 When I got off the runway and sh= ut it down I had a trail of coolant behind me.=C2=A0 I pulled the cowl off and had20coolant all over the botto= m cowl where my over flow tube dumps out but no sign of hose or fitting failures.=C2=A0 Sunday after letting it coo= l overnight I swung the prop through and it still has good compression from the sound of it.=C2=A0 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.=C2=A0 The coolant= was just running out the weep hole on the water pump. =C2=A0 I would like to know if anyone else has had=C2=A0problems with water pumps= =C2=A0and any comments. =C2=A0 Mike Perry N981MP Long Ez =C2=A0 =C2=A0http://www.tohoflyer.com/ =C2=A0 =C2=A0 =C2=A0 ----- Original Message ----- From: Mark Steitle To: Rotary motors in aircraft Sent: Monday, April 13, 2009 9:16 AM Subject: [FlyRotary] Re: forced landings =C2=A0 Dave, =C2=A0 I have decided to take Al's suggestion and=C2=A0limit=C2=A0the criteria fo= r the spreadsheet to basically include any in-flight system failure which= interrupts the planned flight and results in a premature landing.=C2=A0= Based on this, I will add #3 & #4 as well as the one=C2=A0resulting from= =C2=A0a ruptured coolant hose.=C2=A0 =C2=A0 Mark S. On Mon, Apr 13, 2009 at 7:55 AM, David Leonard wrote= : Mark, And did you get these?=C2=A0 Added by me and John Slade under the wr ong thread title: On Sun, Apr 12, 2009 at 5:15 PM, John Slade wr= ote: Here's a few for the list, Mark, 1. Stock turbo bearings collapsed & took out apex seal. Flew home at reduc= ed power. =C2=A0 2. Fuel filer (sinstered bronze) looked clean but was restricting fuel flo= w. Flew home on other tank. =C2=A0 3. Bad / intermittent contact on ignition timing sensor made engine run ro= ugh. Landed normally and repaired. =C2=A0 4. Turbo hose blew off on take-off. Returned to land at reduced power. John ------=C2=A0 =C2=A0 Been there, done that. (the blown-off intake hose) =C2=A0 Also: I have burned out 2 turbos.=C2=A0 The first caused precautionary/urgent la= nding at an airport pending shutting off fuel flow to the turbo.=C2=A0 The= second, I flipped a turbo oil shut off switch and flew 1000NM to get home= . =C2=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 phase= one flying (after major change)...=C2=A0 landed normally=C2=A0 Forgot to re-connect fuel return line in engine bay after doing some work.= =C2=A0 dumped a couple gallons of fuel onto the running engine until I sme= lled 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 test= ing.=C2=A0 Would have lost cooling and alternator if it happened now. PSRU sun gear pin broke from a backfire during run-up.=C2=A0 Was able to taxi back but= would not have been able to fly. =C2=A0 This is good - broke a coolant line in flight and smelled coolant...=C2=A0= landed at nearby airport and taxied up to restaurant with steam spewing= out of the cowl.=C2=A0 Me and my buddy calmly walked into the restaurant= and had breakfast.=C2=A0 Afterward, we borrowed some tools and fixed the= coolant line.=C2=A0 Went back into the restaurant to ask for 2 pitchers= of water to put in our plane.=C2=A0 Continued ski trip to Mammoth.=C2=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 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.=C2=A0 These last two, along with Ed's= brake fire, and an oil coolant rupture, totals four incidents involving= fires during ground operations.=C2=A0 Hopefully, everyone carries at leas= t one fire extinguisher in their airplane. Mark S. =C2=A0 On Sun, Apr 12, 2009 at 2:56 PM, Bill Schertz wrote= : 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. =C2=A0 From=C2=A0 my post of Feb. 8 Well, I haven't heard of this happening before -- I was ground running my= engine to=3DC 2 tune it with the EM-2 and EC-2.=C2=A0 Ran for almost an hour, at various= rpm's to change the manifold pressure and tweak the settings. Cooling wor= king 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. =C2=A0 Engine was running good, took it up to ~6000 rpm swinging a 76x76 Catto pr= op, when suddenly there was steam and fluid on my windshield. Shut it down= by killing power to the EC-2. Coolant everywhere. =C2=A0 Got out and looked to diagnose the problem -- NOT my plumbing.=C2=A0 A FRE= EZE PLUG in the iron housing had blown out. Rapid coolant dump. =C2=A0 Secondary effect -- Since I shut down suddenly from full tilt, either the= proximity of the cowl to the exhaust, or possibly some of the coolant on= the exhaust started a small fire on my cowl. Put it out with extinguisher= , but corner is charred. =C2=A0 Now in repair mode. =C2=A0 -------------------------- Update since this incident:=C2=A0 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. =C2=A0 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 landin gs =C2=A0 Charlie, That's a very good point.=C2=A0 I'm trying to stay away from assigning a= "cause" for whatever happened because I don't have all the facts.=C2=A0= I have a field that says "Explanation of Failure".=C2=A0 Hopefully, we ca= n make statements as you suggest.=C2=A0 Sometimes, even the FAA gets it wr= ong, like the time they attributed the engine failure to the builder remov= ing the oil injection pump.=C2=A0 Also, I doubt that we could all agree on= a "single cause" for each failure.=C2=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.=C2=A0 What I hope to accomplish is to poi= nt out areas where we need to be more careful on how we design a particula= r part or system.=C2=A0 List is at 16 now.=C2=A0 Anyone else want to add a "dark and stormy night"= story to the list?=C2=A0 Mark =C2=A0=C2=A0 On Sun, Apr 12, 2009 at 11:46 AM, Charlie England wrote: I think that it's just as important to understand the real cause of the fa= ilure. 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 plas= tic in the wrong area without any protection. The homebuilder's knee-jerk= reaction is to say 'no plastic sensors because that one melted', even tho= ugh there are tens of thousands of the same sensor in use in boating, a mu= ch more severe environment. Kind of like=3D2 0the canard builder who tried to put fuel in a wing built with fuel-solubl= e foam. Obviously, it failed, but only because of the wrong application of= products, not the products themselves. Charlie =C2=A0 From: al wick To: Rotary motors in aircraft Sent: Sunday, April 12, 2009 10:13:00 AM Subject: [FlyRotary] Re: forced landings =C2=A0 Absolutely excellent Mark. I'd encourage you to get the year the incident= occured too. That will be your proof of reduced risk from things like thi= s 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=C2=A0a 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 guess on some= facts. For example, you could check faa database and find 100 planes regi= stered with rotary engine in 2005. You can guess that equals 70 hours each= . Even 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 your number= s 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= fuel line. It melted, he died. Tracy just reported hot exhaust caused fue= l to boil out of carb. These have the same=C2=A0root cause. You don't want= 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 here, with a bit of fibre= fax 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 rat= ionalized 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 forc= ed landing? Here's what I recall from memory, so it likely is missing a few; =C2=A0 =C2=A0=C2=A0=C2=A0 3 forced landings due to ruptured oil coolers =C2=A0=C2=A0=C2=A0 1 forced landing due to apex seal coming out of its slo= t (rotor out of spec) =C2=A0=C2=A0=C2=A0 1 forced landing due to impro per assembly of engine (seal wedged between rotor & side housing) =C2=A0=C2=A0=C2=A0 1 forced landing on highway due to catastrophic overhea= ting of engine =C2=A0=C2=A0=C2=A0 2 forced landings (one fatal) due to probable fuel syst= em design flaw=C2=A0 =C2=A0=C2=A0=C2=A0 1 forced landing on highway due to ingestion of FOD.=C2= =A0 There were a few others, such as turbo failures which allowed for continue= d operation at reduced power, so we may or may not wish to include those= here.=C2=A0 While a number of these incidents date back quite a few years, and we have= made excellent progress, it says to me that we still have room for improv= ement in the peripheral department.=C2=A0 The good news is that out of all= of the incidents listed above, none of them were caused by a true engine= failure.=C2=A0 That's where the rotary has really earned my respect as a= viable a/c engine. Pay attention to the details! Mark S. On Sat, Apr 11, 2009 at 9:22 PM, Mike Wills wrote: This has been an interesting thread. In the end, it doesnt really matter= how many "major" parts you have - even a minor failure can bring you down= . While I believe the basic rotary engine itself is more fault tolerant th= an a recip, the peripherals used in the typical rotary install are a lot= more complex than a typical recip install. Since we rotary fliers dont ha= ve the benefit of 70 years worth of experience flying behind the typical= LyCon farm implement I think o verall our odds are considerably worse. Comes down to how well an individu= al engineer's his installation and there is a tremendous amount of variati= on here. =C2=A0 The dependence on electronics in the typical rotary install=C2=A0 is a goo= d example. I may be a little=C2=A0sensitive to this issue since I've been= trying to find an intermittent glitch (2 times in 22 hours of engine test= ing). =C2=A0 Mike Wills RV-4 N144MW=C2=A0=C2=A0 ----- 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 =C2=A0 Good analysis and logic, Gary. =C2=A0 You=E2=80=99d make a good addition to the =E2=80=9Crotary community=E2=80= =9D.=C2=A0 I have noticed 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 problems =E2=80=93 even cooling is OK {:>).=C2=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.=C2= =A0 =C2=A0 I know that fewer parts count is often touted as one of the rotary benefit= =E2=80=93 and while it is true that the part count is lower, the most sig= nificant thing (in my opinion) is not only does the lower part count help reliability (if it is not there =E2=80=93 it can= not break), but if you look a the design of the eccentric shaft (for exam= ple) you notice the absence of the jogs in a typical crankshaft and their= stress points.=C2=A0 The thing is over 3=E2=80=9D in diameter at some poi= nts and does not have the same inertia loads born by a piston crankshaft.= =C2=A0 The parts that are there are of very robust design.=C2=A0 Finally,= the rotary is (I believe) more tolerant of damage and tends to fail =E2= =80=9Cgradually and gracefully=E2=80=9D, it can take a licking and keep on= ticking as the old saying goes.=C2=A0 Only extended time and numbers will= provide the true MTBF for the rotary, but I believe it looks very promisi= ng. =C2=A0 Failure of rotary engines are extremely rare, but unfortunately, as with= many alternative engine installations, auxiliary subsystems such as fuel= and ignition frequently being one-off designs have been the cause of most= failures =E2=80=93 with probably fuel the prime culprit.=C2=A0 The good= news is that for some platforms (such as the RVs) we have pretty much est= ablished what will make an installation successful.=C2=A0 The Canard crowd= is fast approaching that status with their somewhat more challenging cool= ing requirements being over come. =C2=A0 =C2=A0 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 later= =E2=80=93 my fault for not being aware of this spec limit and checking it= ) which20led to apex seal failure and consequence lost of most of the powe= r from one rotor, I was still able to maintain 6500 MSL at WOT and fuel mi= xture knob to full rich =E2=80=93 flowing 14.5 GPH =E2=80=93 a lot of it= undoubtedly =C2=A0being blown through the disabled rotor.=C2=A0 Flew it= back 60 miles to a suitable runway and made a non-eventful landing.=C2=A0= =C2=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 needl= es on the gauges.=C2=A0 Other folks have had FOD damage to a rotor and als= o make it to a safe landing.=C2=A0 Two folks lost cooling (one loss of coo= lant fluid , one lost of water pump) and while they did cook the engines,= both made it back to a safe landing.=C2=A0 So all things considered, I th= ink the rotary continues to show that if the installation is designed prop= erly, it makes a very viable and reliable aircraft power plant. =C2=A0 Failure of rotary engines in aircraft are extremely rare, but unfortunatel= y, as with many alternative engine installations, auxiliary subsystems suc= h as fuel and ignition frequently being one-off designs - have been the ca= use of most failures.=C2=A0 The good news is that for some platforms (such= as the RVs) we have pretty much established what will make an installatio= n successful.=C2=A0 The Canard crowd is fast approaching that status with= their somewhat more challenging cooling requirements being over come. =C2=A0 My rotary installation cost me $6500 back in 1996, the primary cost being a rebuilt engine $2000 and the PSRU $2900.=C2=A0 I= have since purchased a 1991 turbo block engine from Japan for $900 and re= built it myself for another $2200. =C2=A0My radiators (GM evaporator cores= ) cost $5.00 from the junk yard and another $50.00 each for having the bun= gs welded on.=C2=A0 So depending on how much you buy and how much you buil= d the price can vary considerably.=C2=A0 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 =E2=80=93 some folks could do it for less,= some for more. =C2=A0 But, regardless of the technical merit (or not) in someone=E2=80=99s mind,= the crucial thing (in my opinion) is you need to address two personal fac= tors: =C2=A0 1.=C2=A0 What is your risk tolerance?=C2=A0 It doesn=E2=80=99t really matt= er how sexy some =E2=80=9Cexotic=E2=80=9D engine installation may seem =E2= =80=93 if you are not comfortable flying behind (or in front) of it, then= it certainly does not =C2=A0makes sense to go that route.=C2=A0 After all= , this is supposed to have an element of fun and enjoyment to it. =C2=A0 2.=C2=A0 What is your knowledge, experience and background (and you don=E2= =80=99t have to be an engineer) and do you feel comfortable with the level= of involvement needed. =C2=A0 So hope you continue to contribute to expanding our knowledge and understa= nding of the rotary in its application to power plant for aircraft. =C2=A0 =C2=A0 Best Regards =C2=A0 Ed A 0 =C2=A0 Ed Anderson Rv-6A N494BW Rotary Powered Matthews, NC eanderson@carolina.rr.com http://www.andersonee.com http://www.dmack.net/mazda/index.html 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 Be= half Of Gary Casey Sent: Saturday, April 11, 2009 8:36 AM To: Rotary motors in aircraft Subject: [FlyRotary] Re: Rotary Engines =C2=A0 Just to add a few more comments and answers to the several excellent comme= nts posted: =C2=A0 How many parts does it take to make a rotary rotate? =C2=A0Well, "parts ar= en't parts" in this case. =C2=A0Mark was right in that there are maybe 4= "major" components, but you have to define major. =C2=A0A piston engine= certainly has far more major parts. =C2=A0Is a valve a "major" part? =C2= =A0I think so. =C2=A0Is a rotor corner button a major part? =C2=A0Not sure= , but probably not. =C2=A0Is each planet gear in the PSRU a major part? = =C2=A0I say yes, and the PSRU is an integral part of the rotary engine. = =C2=A0As someone correctly pointed out, it's not how many parts, but the= reliability of the total system that counts. =C2=A0Just looking at the hi= story of the rotary (which, from the implication of another post) it's not= that good, but I don't think it has anything to do with reliability of th= e concept. =C2=A0It's more to do with the experimental nature of the build= s and installations. =C2=A0My original point, perhap s not well expressed is that to say there are just 4 parts is an oversimpl= ification. =C2=A0But 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.. =C2=A0 Are we ES drivers more conservative? =C2=A0Probably so, since the ES is pr= obably one of the experimentals most similar to production aircraft, and= not just because the Columbia (can't force myself to say Cezzna :-) was= a derivative. =C2=A0Therefore, it tends to attract conservative builders= and owners. =C2=A0Not surprising then that almost all ES's have tradition= al powerplants, with the most excellent exception of Mark. =C2=A0While the= re may be more, I know of only two off-airport landings caused by engine= failures in the ES in almost 20 years of experience. =C2=A0One was caused= by fuel starvation right after takeoff (fatal) and one was caused by a PS= RU failure in an auto engine conversion. =C2=A0So our old-fashioned conser= vative nature has served us pretty well. =C2=A0 Yes, I was assuming that the rotary had electronic fuel injection and igni= tion, but that by itself doesn't change the inherent fuel efficiency of th= e engine. =C2=A0Direct injection does have a potential to improve BSFC bec= ause the fuel charge can be stratified. =C2=A0It will probably decrease av= ailable power, though. =C2=A0I think the best rotary will be 5% less effic= ient than the "best" piston engine(same refinements added to each). =C2=A0= But I stated that as a simple disadvantage - as Mark pointed out, it isn't that simple. =C2=A0The rotary already comes configured to ru= n on auto gas. =C2=A0The piston engine can also be so configured, but the= compression ratio reduction would reduce its BSFC and maybe durability ad= vantage. =C2=A0The total operating cost is certainly significantly less if= auto gas can always be used to refuel. =C2=A0I assumed in my assessment= that it will only be available 50% of the time. =C2=A0The real disadvanta= ge, which I failed to state, is that the extra fuel required for a given= mission might be 5 or 10% higher and that negated the weight advantage,= if only for long-range flights. =C2=A0 Is the engine less expensive? =C2=A0I did a thorough analysis of a direct-= drive recip auto engine installation and my conclusion was that if the aut= o engine were equivalent in reliability to the aircraft engine it would li= kely cost just as much. =C2=A0Is the same true of the rotary? =C2=A0I'm no= t sure, but you have to consider the total cost, including engineering of= all the parts in the system, not just the core engine. =C2=A0I would love= to do a rotary installation, but I don't think I could justify it by cost= reduction. =C2=A0 It wasn't mentioned in the posts, but some have claimed the rotary is "smo= other" than a recip. =C2=A0I at first resisted that notion. =C2=A0Sure, an= y rotary given sufficient counterbalancing, is perfectly balanced. =C2=A0A= 4-cylinder opposed recip is not - there is a significant secondary couple= . =C2=A0The 6-cylinder opposed engine is perfectly balance d, but only for PRIMARY and SECONDARY forces and couples - higher order fo= rces have never really been analyzed, although they would be very small.= =C2=A0And then consider the forces within the engine that have to be resi= sted by that long, heavy, but flexible crankshaft. =C2=A0So it isn't the= mechanical balance that gives the rotary an advantage. =C2=A0Let's take= a look at the the torsional pulsations, comparing the 3-rotor against the= 6-cylinder: =C2=A0A 6-cylinder engine has 3 power impulses per rotation,= as does the 3-rotor, so they are the same, right? =C2=A0Wrong. =C2=A0They= both incorporate 4 "stroke" cycles, meaning that there separate and seque= ntial intake, compression, power and exhaust events so that is the same fo= r both. =C2=A0The power event, which is the source of the torque impulse,= =C2=A0takes 1/2 of a crank rotation for the recip. =C2=A0In the rotary the= power event requires 1/4 of a ROTOR rotation, but the rotor rotates at 1/= 3 crank rotation - the result is that the power impulse lasts 3/4 of a CRA= NK rotation, 50% longer than in a recip. =C2=A0Therefore, the torsional ex= citation delivered to the propeller, PSRU and to the airframe is significa= ntly less than for a recip. =C2=A0And if you analyze the actual forces imp= arted, they go down by the square of the rpm. =C2=A0The torsional vibratio= n amplitude goes down by a factor of 4 just because the rpm of the rotary= turns about twice as fast. =C2=A0If you've skipped to the bottom of the= paragraph, as you probably should have :-), yes the rotary is "smoo ther" - a LOT smoother.. (my apologies to rotary purists, for simplicity= I used the word "crankshaft" for both engines) =C2=A0 But just because you can burn auto gas should you? =C2=A0The biggest probl= ems with auto gas in recip aircraft have nothing to do with the engine, bu= t with the high vapor pressure of the fuel - it is more prone to vapor loc= k. =C2=A0The fuel systems of certified aircraft are not particularly well= designed with regard to vapor lock. =C2=A0"Fortunately", rotary engines= typically have no mechanical fuel pump and are forced to rely on electric= pumps. =C2=A0Fortunately because the pumps can be located at the very bot= tom of the aircraft and close to the fuel tanks, making vapor lock much le= ss likely. =C2=A0I would caution any builders to consider vapor lock possi= bilities very seriously, much more so if you intend to run auto gas. =C2= =A0when I was going to do this I planned to put one electric pump in the= wing root of each wing, feeding the engine directly(the check valve in th= e non-running pump prevents back-feeding). =C2=A0Redundancy was by a "cros= sfeed" line that could connect the tanks together. =C2=A0 And thanks, Mark for - probably incorrectly - referring to me as a "good= engineer". =C2=A0I'll have to put that in my resume! =C2=A0 Have a good day, Gary (do you allow us outsiders in your events? =C2=A0I'll park well away :-) =C2=A0 __________ Information from ESET NOD32 Antivirus, version of viru s signature database 3267 (20080714) __________ The message was checked by ESET NOD32 Antivirus. http://www.eset.com/ =C2=A0 =C2=A0 =C2=A0 -- David Leonard Turbo Rotary RV-6 N4VY http://N4VY.RotaryRoster.net http://RotaryRoster.net =C2=A0 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: 04/13/09= 05:51:00 =C2=A0 ----------MB_8CB8B43F1316CE0_96C_1CD6_FWM-D40.sysops.aol.com Content-Transfer-Encoding: quoted-printable Content-Type: text/html; charset="utf-8" Something to note guys the EG/water mix keeps the seal lubed. If you run= plain water (it cools better) get some RedLine water wetter, it has= a seal lube in it. Evans is also supposed to be goodd for the seal. FWIW.=
Bill Jepson 


-----Original Message-----
From: Ed Anderson <eanderson@carolina.rr.com>
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
Sent: Mon, 13 Apr 2009 5:46 pm
Subject: [FlyRotary] Re: forced landings

Mike, I agree with= William =E2=80=93 Probably  just unlucky.  I have flow with a= 86 water pump for over 10 years including over heating, coolant pressure= up to 23 psi (or higher) and the old pump just keeps going strong. = So I moved it from my 86 N/A engine to my 91 turbo block (I have JCN thre= ads cut into the pump intake =E2=80=93 so I can thread an AN-16 fitting in= to it).
 
I also have a racin= g beat =E2=80=9Cunderdrive=E2=80=9D main pulley which slows down the water= pump rpm.  I also have one on my alternator (also over 10 years of= flying).
 
OR the rebuild joy= on your water pump may just not have been up to snuff.
 
Ed
 
Ed Anderson
Rv-6A N494BW Rotary Powered=
From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On Behalf Of William Wilson
Sent: Monday, April 13, 20= 09 8:34 PM
To: Rotary motors in aircr= aft
Subject: [FlyRotary] Re:= forced land ings
 
I think you just got= unlucky.  But...

The stock water pumps are not really intended for extended high RPM operat= ion.  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 you have an air pump or air conditioner).  Slowing the water pum= p 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 <MKPerry99@cfl.rr.com> wrote:
Here is another to add to the list.  "Wa= ter 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 fl ight.
Since this was the original pump on my 1986= 13B I figured it was well past 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<= /div>
rebuilds.
 
This last Saturday at 72 hours on the engine= I took off for my second test flight with a new IVO Magnum<= /div>
adjustable prop.  Excellent acceleration= and better rate of climb than my home made composite prop.<= /div>
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.  Oi= l temps have always been below 190.
 
At medium pitch on the IVO I was close to 600= 0 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<= /SPAN>
down as I flew out to my test area over the= sod farms. After 15 minutes of 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 4000 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 no= w 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<= /SPAN>
never missed a beat the whole time.  Whe= n I got off the runway and shut it down I had a trail of coolant
behind me.  I pulled the cowl off and ha= d coolant all over the bottom cowl 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.&nb= sp; 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&n= bsp;problems with water pumps and any comments.
 
Mike Perry
N981MP
Long Ez
 
 http://www.tohoflyer.com/
 
 
 
----- Original Message -----
From: Mark Steitle
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 prema= ture 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 <wdleonard@gmail.com> wrote:<= /SPAN>
Mark, And did you get these?  Added by me and Jo= hn Slade under the wrong thread title:

On Sun, Apr 12, 2009 at 5:15 PM, John Slade <jslade@canardaviation.com> wrote:<= /div>
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 flo= w. Flew home on other tank.
 
3. Bad / intermittent contact on ignition timing sensor made engine run ro= ugh. 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 pr= ecau tionary/urgent landing 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.(soft failure)
I had a bad injector enable switch causing rough runn= ing during some phase one flying (after major change)...  landed norm= ally 

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 sme= lled 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 test= ing.  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 sme= lled 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 our plane.  Continued ski trip= to Mammoth.  The end.
--
David Leonard
On Sun, Apr 12, 2009 at 2:03 PM, Mark Steitle <msteitle@gmail.com> 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= brake fire, and an oil coolant rupture, totals four incidents involving= fires during ground operations.  Hopefully, everyone carries at leas= t one fire extinguisher in their airplane.

Mark S.
 
On Sun, Apr 12, 2009 at 2:56 PM, Bill Schertz <wschertz@comcast.net> wrote:<= /SPAN>
One other thing to watch out for -- This occu= rred during ground testing, but if it had happened in the air it would hav= e been a forced landing.
 
From  my post of Feb. 8
Well, I haven't heard of this happening befor= e -- 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 cowl= ing off to allow good exit area since I was tied down. Coolant pressure ab= out 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 ever= ywhere.
 
Got out and looked to dia gnose the problem -- NOT my plumbing.  A FREEZE PLUG in the iron hous= ing had blown out. Rapid coolant dump.
 
Secondary effect -- Since I shut down suddenl= y from full tilt, either the proximity of the cowl to the exhaust, or poss= ibly some of the coolant on 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 been replaced by Bruce Turrentine, and he ha= s inspected the engine. I am currently reinstalling it and getting ready= for more tuning exercises.
=3D0 A
 
Bill Schertz
KIS Cruiser #4045
N343BS
----- Original Message -----
From: Mark Steitle
Sent:= Sunday, April 12, 2009 1:51 PM
Subject:<= /B> [FlyRotary] Re: forced landings
 
Charlie,
That's a very good po= int.  I'm trying to stay away from assigning a "cause" for whatever= happened because I don't have all the facts.  I have a field that sa= ys "Explanation of Failure".  Hopefully, we can make statements as yo= u suggest.  Sometimes, even the FAA gets it wrong, lik e the time they attributed the engine failure to the builder removing the= oil injection pump.  Also, I doubt that we could all agree on a "sin= gle cause" for each failure.  Maybe it is due to a poor weld, or wron= g 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 are= as where we need to be more 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 r eaction is to say 'no plastic sensors because that one melted', even thoug= h 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 ap= plication of products, not the products themselves.

Charlie
 
From: al wick <alwick@juno.com<= /A>>
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 incide= nt 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. Becau= se 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= objective in your rating.
The final piece is about how many flight hours, first flights there wer= e. Each year there are more engines flying, so way more likely you will he= ar of incident. A wild assed guess is ok, if you just base the guess on so= me facts. For example, you could check faa database and find 100 planes re= gistered with rotary engine in 2005. You can guess that equals 70 hours ea= ch. Even though it's a wild ass ed 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 "contrib= uting factors". Then you can dramatically reduce personal risk. Good examp= le: We had that guy that installed plastic fuel flow sensor in fuel 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 say:"= I have efi, can't happen to me". You want to say:" I expect heat will cau= se 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 <msteitle@gmai= l.com>
To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
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 forc= ed 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 slo= t (rotor out of spec)
    1 forced landing due to improper assembly of engine (se= al wedged between rotor & side housing)
    1 forced landing on highway due to catastrophic overhea= ting of engine
    2 forced landings (one fatal) due to probable fuel syst= em design flaw 
    1 forced landing on highway due to ingestion of FOD.&nb= sp;

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

While a number of these incidents date back quite a few years, and we have= made excellent progress, it says to me that we still have room for improv= em ent 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 engine= failure.  That's where the rotary has really earned my respect as a= viable 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. In the= end, it doesnt really matter how many "major" parts you have - even a min= or failure can bring you down. While I believe the basic rotary engine its= elf is more fault tolerant than a recip, the peripherals used in the typic= al rotary install are a lot more complex than a typical recip install. Sin= ce we rotary fliers dont have the benefit of 70 years worth of experience= flying behind the typical LyCon farm implement I think overall our odds= are consider ably worse. Comes down to how well an individual engineer's his installati= on and there is a tremendous amount of variation here.
 
The dependence on electronics in the typical= rotary install  is a good example. I may be a little sensitive= to this issue since I've been trying to find an intermittent glitch (2 ti= mes in 22 hours of engine testing).
 
Mike Wills<= /SPAN><= /FONT>
RV-4 N144MW=  &= nbsp;
----- Original Message -----
Sent:= Saturday, April 11, 2009 7:31 AM
Subject:<= /B> [FlyRotary] Gary Casey was [FlyRotary] Re: Rotary Engines=
 
Good analysis and logic, Gary.=
 
You=E2=80=99d make a good addition to= the =E2=80=9Crotary community=E2=80=9D.  I have noticed 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 problems =E2=80= =93 even cooling is OK {:>).  I believe most of this improvement= can be attributed to folks sharing their knowledge, problems and solution= s with others - such as on this list. 
 
I know that fewer parts count is= often touted as one of the rotary benefit =E2=80=93 and while it is true= that the part count is lower, the most significant thing (in my opinion)= is not only does the lower part count help reliability (if it is not ther= e =E2=80=93 it can not break), but if you look a the design of the eccentr= ic shaft (for example) you notice the absence of the jogs in a typical cra= nkshaft and their stress points.  The thing is over 3=E2=80=9D in dia= meter at some points and does not have the same inertia loads born by a pi= ston crankshaft.  The parts that are there are of very robust design.=   Finally, the rotary is (I believe) more tolerant of damage and tend= s to fail =E2=80=9Cgradually and gracefully=E2=80=9D, it can take a lickin= g and keep on ticking as the old saying goes.  Only extended time and= numbers will provide the true MTBF for the rotary, but I believe it looks= very promising.
 
Failure of rotary engines are extreme= ly rare, but unfortunately, as with many alternative engine installations,= auxiliary subsystems such as fuel and ignition frequently being one-off= designs have been the cause of most failures =E2=80=93 with probably fuel= the prime culprit.  The good news is t hat for some platforms (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 requ= irements being over come.
 
  Having lost a rotor during fli= ght due to putting in high compression rotors with worn apex seal slots wo= rn beyond specs (found this out later =E2=80=93 my fault for not being awa= re of this spec limit and checking it) which 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 =E2=80=93 flo= wing 14.5 GPH =E2=80=93 a lot of it undoubtedly  being blown through= the disabled rotor.  Flew it back 60 miles to a suitable runway and= made a non-eventful landing.   There was a small increase in vi= bration due to the power strokes no longer being balanced, but nothing bad= and you could still read the needles on the gauges.  Other folks hav= e 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 engines, both made it back to a safe landing.=   So all things considered, I think the rotary continues to show that if the installation is designed properly, it makes a very viable and= reliable aircraft power plant.
 
Failure of rotary engines in aircraft= are extremely rare, but unfortunately, as with many alternative engine in= stallations, auxiliary subsystems such as fuel and ignition frequently bei= ng one-off designs - have been the cause of most failures.  The good= news is that for some platforms (such as the RVs) we have pretty much est= ablished what will make an installation successful.  The Canard crowd= is fast approaching that status with their somewhat more challenging cool= ing 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 purchased a 1991 turbo block engine from Japan= for $900 and rebuilt it myself for another $2200.  My radiators (GM= evaporator cores) cost $5.00 from the junk yard and another $50.00 each= for having the bungs welded on.  So depending on how much you buy an= d how much you build the price can vary considerably.  Today, I would= say20it would take a minimum of around $8000 and more nominally around $1= 0000 for a complete rotary installation in an RV =E2=80=93 some folks coul= d do it for less, some for more.
 
But, regardless of the technical meri= t (or not) in someone=E2=80=99s mind, the crucial thing (in my opinion) is= you need to address two personal factors:
 
1.  What is your risk tolerance?=   It doesn=E2=80=99t really matter how sexy some =E2=80=9Cexotic=E2= =80=9D engine installation may seem =E2=80=93 if you are not comfortable= 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 elem= ent of fun and enjoyment to it.
 
2.  What is your knowledge, expe= rience and background (and you don=E2=80=99t 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 applicatio= n to power plant for aircraft.
 
 
Best Regards
 
Ed
 
 
Ed Anderson
Rv-6A N494BW Rotary Powered=
Matthews, NC<= /div> eanderson@carolina.rr.com
=3D0 A
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 aircr= aft
Subject: [FlyRotary] Re:= Rotary Engines
 
Just to add a few more comments and answers to the several excellent co= mments 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= certainly has far more major parts.  Is a valve a "major" part? &nbs= p;I think so.  Is a rotor corner button a major part?  Not sure,= but probably not.  Is each planet=3D2 0gear in the PSRU a major part?  I say yes, and the PSRU is an integr= al part of the rotary engine.  As someone correctly pointed out, it's= not how many parts, but the reliability of the total system that counts.=  Just looking at the history of the rotary (which, from the 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 exp= erimental nature of the builds and installations.  My original point,= perhaps not well expressed is that to say there are just 4 parts is an ov= ersimplification.  But let's face it, to put in an engine that has ha= d many thousands of identical predecessors is less "experimental" than one= that hasn't..
 
Are we ES drivers more conservative?  Probably so, since the ES is= probably one of the experimentals most similar to production aircraft, an= d not just because the Columbia (can't force myself to say Cezzna :-) was= a derivative.  Therefore, it tends to attract conservative builders= and owners.  Not surprising then that almost all ES's have tradition= al powerplants, with the most excellent exception of Mark.  While the= re may be more, I know of only two off-airport landings caused by engine= failures in the ES in almost 20 years of experience. & nbsp;One was caused by fuel starvation right after takeoff (fatal) and one= was caused by a PSRU failure in an auto engine conversion.  So our= old-fashioned conservative nature has served us pretty well.
 
Yes, I was assuming that the rotary had electronic fuel injection and= ignition, but that by itself doesn't change the inherent fuel efficiency= of the engine.  Direct injection does have a potential to improve BS= FC because the fuel charge can be stratified.  It will probably decre= ase available power, though.  I think the best rotary will be 5% less= efficient than 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 engine can also be so configured, but the comp= ression ratio reduction would reduce its BSFC and maybe durability advanta= ge.  The total operating cost is certainly significantly less if auto= gas can always be used to refuel.  I assumed in my assessment that= it will only be available 50% of the time.  The real disadvantage,= which I failed to state, is that the extra fuel required for a given miss= ion might be 5 or 10% higher and that negated the weight advantage, if onl= y for long-range flig hts.
 
Is the engine less expensive?  I did a thorough analysis of a dire= ct-drive recip auto engine installation and my conclusion was that if the= auto engine were equivalent in reliability to the aircraft engine it woul= d 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 reduction.
 
It wasn't mentioned in the posts, but some have claimed the rotary is= "smoother" than a recip.  I at first resisted that notion.  Sur= e, any rotary given sufficient counterbalancing, is perfectly balanced. &n= bsp;A 4-cylinder opposed recip is not - there is a significant secondary= couple.  The 6-cylinder opposed engine is perfectly balanced, but on= ly 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 forces within the engine that have to be=3D2 0resisted by that long, heavy, but flexible crankshaft.  So it isn't= the mechanical balance that gives the rotary an advantage.  Let's ta= ke a look at the the torsional pulsations, comparing the 3-rotor against= the 6-cylinder:  A 6-cylinder engine has 3 power impulses per rotati= on, as does the 3-rotor, so they are the same, right?  Wrong.  T= hey both incorporate 4 "stroke" cycles, meaning that there separate and se= quential 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 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 torsio= nal excitation delivered to the propeller, PSRU and to the airframe is sig= nificantly less than for a recip.  And if you analyze the actual forc= es imparted, they go down by the square of the rpm.  The torsional vi= bration amplitude goes 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 probably should have :-), yes the rotary is "smo= other" - a LOT smoother.. (my apologies to rotary purists, for simplicity= I used the word "crankshaft" for both engines)
 
But just because you can burn auto gas should you?  The biggest pr= oblems 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 vapor= lock.  The fuel systems of certified aircraft are not particularly= well designed with regard to vapor lock.  "Fortunately", rotary engi= nes typically have no mechanical fuel pump and are forced to rely on elect= ric pumps.  Fortunately because the pumps can be located at the very= bottom of the aircraft and close to the fuel tanks, making vapor lock muc= h less likely.  I would caution any builders to consider vapor lock= possibilities very seriously, much more so if you intend to run auto gas.=  when I was going to do this I planned to put one electric pump in= the wing root of each wing, feeding the engine directly(the check valve= in the non-running pump prevents back-feeding).  Redundancy was by= a "crossfeed" line that could connect the tanks together.
 
And thanks, Mark for - probably incorrectly - referring to me as a "goo= d 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 :-= )
 



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