X-Virus-Scanned: clean according to Sophos on Logan.com X-PolluStop-Diagnostic: (direct reply)\eX-PolluStop-Score: 0.00\eX-PolluStop: Scanned with Niversoft PolluStop 2.1 RC1, http://www.niversoft.com/pollustop Return-Path: Received: from [24.25.9.100] (HELO ms-smtp-01-eri0.southeast.rr.com) by logan.com (CommuniGate Pro SMTP 4.3c4) with ESMTP id 868743 for flyrotary@lancaironline.net; Thu, 14 Apr 2005 12:14:05 -0400 Received-SPF: pass receiver=logan.com; client-ip=24.25.9.100; envelope-from=eanderson@carolina.rr.com Received: from edward2 (cpe-024-074-185-127.carolina.res.rr.com [24.74.185.127]) by ms-smtp-01-eri0.southeast.rr.com (8.12.10/8.12.7) with SMTP id j3EGDGLw027089 for ; Thu, 14 Apr 2005 12:13:17 -0400 (EDT) Message-ID: <000a01c5410c$e2944cf0$2402a8c0@edward2> From: "Ed Anderson" To: "Rotary motors in aircraft" References: Subject: To or Not to Do was Re: [FlyRotary] Rx-8 Rotors Date: Thu, 14 Apr 2005 12:13:24 -0400 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0007_01C540EB.5B4BE580" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2800.1106 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1106 X-Virus-Scanned: Symantec AntiVirus Scan Engine This is a multi-part message in MIME format. ------=_NextPart_000_0007_01C540EB.5B4BE580 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Thanks, Doug Some good thoughts and insight from a guy who's been with a big OEM = engine maker. =20 However, Just remember while your Lycoming has not failed there are = plenty of Lycoming failures out there. What I think you should read = into this is had a lycoming lost 1/2 of its cylinders to foreign object = damage would it have done any better (or as good) as the rotary did? I = agree that our poor attempt at R&D can never remotely match that of OEM = developers - on the other hand, a lot of their development is for an = engine with different operating conditions which may or may not = translate to good aircraft requirement match. I agree and have long stated that what is good for a Racing rotary is = not necessarily good for an aircraft usage - on the other hand it may = not be bad either. The racers do us a service in my opinion in that = they generally take an engine to its breaking point - you never know the = limits until you exceed them. While not all of their lessons are = germane to our needs, I for one appreciate getting some insight to where = the "real" limits are. I am not fond of exceeding the limits in = aircraft usage - it ruins seat cushions {:>). I don't think your insights or views paint you as a "stick in the mud", = caution in this hobby is a life prolonging trait in my opinion - = however, even the big OEM engine developers show they can get it wrong - = i.e. one example in the news recently are the crankshaft failures that = Lycoming is being sued over. So I think it unrealistic to think we = small guys will never have "incidents" that we would rather not have.=20 Fortunately, I believe that we are reducing the likelihood of incidents = by such mediums as this list. Engines are always going to break - we = just want to get it down to the bear minimum and eliminate those = approaches which seem to hasten such incidents {:>) It is not an area suited to everyone - perhaps not to most people. = While I don't think of myself and other rotary fliers as written in one = national flying magazine as "Hairy Chested Heroes of today's aviation", = I do think you have to have confidence in your ability and the knowledge = to handle such incidents. I don't mean press-on regardless, but to quickly assess = the situation and then make decisions that favor a good outcome. Its a = pucker factor when that old engine starts to rattle, but knowing the = engine is likely to stay together and continue to produce some power if = you stay with it can make a difference. For the new guys, and to put the record straight, I have had three = incidents where I ended up forced to land at airport. Of the three, one = had to do with a fuel tube that separated from a fitting in the fuel = tank, the second one was when my muffler separated from my header and I = deemed it prudent to land, and the only one involving any part of the = engine was this latest incident. So must keep things in their proper = perspective. Take Tracy Crook over 1600 hours and never one forced = landing to my knowledge. Therefore, my conclusion is the engine is a = keeper - no question in my mind or else I would not be looking for = replacement/alternative parts for a rotary - I would be shopping for a = used Lycoming. Best Regards and thanks again for you comments and insight Ed A ----- Original Message -----=20 From: Shearbond@aol.com=20 To: Rotary motors in aircraft=20 Sent: Thursday, April 14, 2005 11:45 AM Subject: [FlyRotary] Rx-8 Rotors Hi Ed: I hate to always appear to be the "stick in the mud" re: the wonderful = "great" ideas that some have to circumvent the $$millions that Mazda = spent over years of R&D. =20 The concept that creates the most anxiety for me re: my fellow EAA'rs = is the reliance on "racers" (Lynn in Columbus excepted) whose objective = is maximum HP for a very short period of time when our usage is = continuous moderate HP over a very extended time. The issues and = constraints are very different. My research into OEM irrigation engines shows that they last from = 25,000-30,000 hours TBO producing approximately 0.5 HP/cubic inch at = 24"-26" MAP. Most run just off WOT at 1,200 - 2500 rpm depending upon = size.....bigger slower, smaller higher rpms. I recall that I calculated = mean piston speed for several and that seems to be the key issue which = determines "specified" rpm. Even when one reduces the TBO by the cube = of the rpm which we desire to use to account for higher BMEP and = rotational forces (squared function), the TBO still comes out to in = excess of 3,000 hours, if someone doesn't muck with the "complete" = system. =20 The point: OEMs have spent $$millions to insure these engines will = produce SPECIFIED HP under an unbelievable range of difficult = conditions. Why would one want to add any single element which would = negate that effort?? Make it produce more HP....of course, but all = durability expectations are Null and Void. Make it produce less HP for = longer....of course, but the price will be high and again, even though = more $$ will have been spent, the expectations are a SWAG....and from my = experience, a very poor result is a high probability. The 13BT will produce....what 250 HP as specified by Mazda??? That = means as designed, it will cool adequately, will function over a large = range of conditions at maximum efficiency at 250 HP. Why would we be so = arrogant as to suppose that we can improve upon that, and for what = reason?? Do not even guess,....that 13BT was run at WOT for many hours = at Maximum HP without failure.....and even worse was cycled back and = forth from max torque rpm WOT to max HP WOT, dumped to idle then back to = max HP, etc....on and on and on! There are hundreds, if not thousands = of combinations of the various components which over hundreds of = thousands of hours of R&D are continuously refined to successfully pass = these tests. I'm certainly not smart enough to know how to improve upon = that. Perhaps that is my issue? If I'm not mistaken you have written a bit on this and have endeavored = to follow "change as little as possible of the major components" as one = of your guidelines. Remove the emission components? Seems OK! Change = the plug wires, perhaps? Change the waterpump when we run at less that = max "specified" rpm? That makes zero sense to me. Change the rotor = seals/materials/oil pump/waterpump/oil flow.......??, go ahead....but = pain hurts like ____, and my insurance rates go up when an EAA'r crashes = and kills themselves! Pardon my passion in this, but too many "experimenters" are ruining = the possibility of success in the use of low-cost, high production, = automotive based engines in aircraft and it is a shame because there is = no fundamental reason that today's modern automotive engines won't = perform admirably, IF utilized properly. Work on the installation, not = on the basic engine. Installed in this manner, the accessories will be = the issue, not the powerplant. IMO for your engine.....Best: buy some new rotors designed for your = housings. Next best: Buy three wreck engines with relatively low = mileage ($300/ea. around here) and measure and pick a rotor which meet = Mazda specifications. Last and probably best and least expensive in the = long run, go purchase an RX8 from a rear-end wreck and put it in, Stock = innards/major components. Keep up the super work and communication. We are counting on you to = be successful. Your latest escapade really threw water on my excitement = re: my project. I had hoped you would process fuel like crazy for a = thousand hours while we watched your R&D/durability results from our = shops!! Continued good luck and POR, Doug in Colorado In a message dated 4/14/05 8:35:12 AM Mountain Daylight Time, = eanderson@carolina.rr.com writes: Hi Doug, Some good thoughts and questions, of which I would like to know the = answers to as well. I believe the reason the experts are recommending = milling the RX-8 rotors for the older seals (when used in the older = rotor housings with peripheral exhausts) is that the RX-8 seal was not = designed to withstand the forces of crossing the exhaust port (in the = Peripheral wall) opening unsupported. Its rather skinny and long. = Mazdatrix reported the RX-8 seals warped as a consequence of the the hot = exhaust gas blowing over them and primarily the lack of wall support at = the exhaust opening(on the older housings). The combination of the = additional heat and lack of wall support appears to be more than the 8 = seal can take. However, I am in basic agreement with you why machine the rotor = when perhaps a new/modified seal is the answer. I want to check with = Tracy Crook since his seals are reportedly 800% stronger than stock apex = seals to see whether the seals could be machined down/created so that = they fit in the RX-8 rotor standard apex slot and still be strong = enough - say 300% stronger than stock {:>). Since they are not made of = typical "gray iron" alloy that the stock and most other seals are made = and chill/case hardened, they may be amenable to machining. Yes, having airports scattered around in just about every county and = sometimes three or more in a county, the geography is much kinder to = engine-out excursions here on the east coast. Fly High, Glide long! = Better yet, keep running on both rotors. Ed A ------=_NextPart_000_0007_01C540EB.5B4BE580 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
Thanks, Doug
 
Some good thoughts and insight from a guy who's been with a big OEM = engine=20 maker. 
 
However, Just remember while your Lycoming has not failed there are = plenty=20 of Lycoming failures out there.  What I think you should read into = this is=20 had a lycoming lost 1/2 of its cylinders to foreign object damage would = it have=20 done any better (or as good) as the rotary did?  I agree that our = poor=20 attempt at R&D can never remotely match that of OEM developers - on = the=20 other hand, a lot of their development is for an engine with different = operating=20 conditions which may or may not translate to good aircraft requirement=20 match.
 
I agree and have long stated that what is good for a Racing rotary = is not=20 necessarily good for an aircraft usage - on the other hand it may not be = bad=20 either.  The racers do us a service in my opinion in that they = generally=20 take an engine to its breaking point - you never know the limits until = you=20 exceed them.   While not all of their lessons are germane to = our=20 needs, I for one appreciate getting some insight to where the "real" = limits=20 are.  I am not fond of exceeding the limits in aircraft usage - it = ruins=20 seat cushions {:>).
 
I don't think your insights or views paint you as a "stick in the = mud",=20 caution in this hobby is a life prolonging trait in my opinion - = however, even=20 the big OEM engine developers show they can get it wrong - i.e. one = example in=20 the news recently are the crankshaft failures that Lycoming is being = sued=20 over.  So I think it unrealistic to think we small guys will never = have=20 "incidents" that we would rather not have.
 
Fortunately, I believe that we are reducing the likelihood of = incidents by=20 such mediums as this list.  Engines are always going to break - we = just=20 want to get it down to the bear minimum and eliminate those approaches = which=20 seem to hasten such incidents {:>)
 
It is not an area suited to everyone - perhaps not to most = people. =20 While I don't think of myself and other rotary fliers as written in one = national=20 flying magazine as "Hairy Chested Heroes of today's aviation", I do = think you=20 have to have confidence in your ability and the knowledge to = handle
such incidents.  I don't mean press-on regardless, but to = quickly=20 assess the situation and then make decisions that favor a good = outcome. =20 Its a pucker factor when that old engine starts to rattle, but knowing = the=20 engine is likely to stay together and continue to produce some power if = you stay=20 with it can make a difference.
 
For the new guys, and to put the record straight, I have had three=20 incidents where I ended up forced to land at airport.  Of the = three, one=20 had to do with a fuel tube that separated from a fitting in the fuel = tank, the=20 second one was when my muffler separated from my header and I deemed it = prudent=20 to land,  and the only one involving any part of the engine was = this latest=20 incident.  So must keep things in their proper perspective.  = Take=20 Tracy Crook over 1600 hours and never one forced landing to my = knowledge.=20 Therefore, my conclusion is the engine is a keeper - no question in my = mind or=20 else I would not be looking for replacement/alternative parts for a = rotary - I=20 would be shopping for a used Lycoming.
 
Best Regards and thanks again for you comments and insight
 
Ed A
 
 
----- Original Message -----
From:=20 Shearbond@aol.com
Sent: Thursday, April 14, 2005 = 11:45=20 AM
Subject: [FlyRotary] Rx-8 = Rotors

Hi Ed:
 
I hate to always appear to be the "stick in the mud" re: the = wonderful=20 "great" ideas that some have to circumvent the $$millions that Mazda = spent=20 over years of R&D. 
 
The concept that creates the most anxiety for me re: my fellow = EAA'rs is=20 the reliance on "racers" (Lynn in Columbus excepted) whose objective = is=20 maximum HP for a very short period of time when our usage is = continuous=20 moderate HP over a very extended time.  The issues and=20 constraints are very different.
 
My research into OEM irrigation engines shows that they last from = 25,000-30,000 hours TBO producing approximately 0.5 HP/cubic inch at = 24"-26"=20 MAP.  Most run just off WOT at 1,200 - 2500 rpm depending upon=20 size.....bigger slower, smaller higher rpms.  I recall that I = calculated=20 mean piston speed for several and that seems to be the key issue which = determines "specified" rpm.  Even when one reduces the TBO by the = cube of the rpm which we desire to use to account for higher = BMEP and=20 rotational forces (squared function), the TBO still comes out to in = excess of=20 3,000 hours, if someone doesn't muck with the = "complete"=20 system. 
 
The point:  OEMs have spent $$millions to insure these = engines will=20 produce SPECIFIED HP under an unbelievable range of difficult=20 conditions.  Why would one want to add any single element which = would=20 negate that effort??  Make it produce more HP....of course, but = all=20 durability expectations are Null and Void.  Make it produce less = HP for=20 longer....of course, but the price will be high and again, even though = more $$=20 will have been spent, the expectations are a SWAG....and from my = experience, a=20 very poor result is a high probability.
 
The 13BT will produce....what 250 HP as specified by=20 Mazda???  That means as designed, it will cool adequately, will = function=20 over a large range of conditions at maximum efficiency at 250 = HP.  Why=20 would we be so arrogant as to suppose that we can improve upon that, = and for=20 what reason??   Do not even guess,....that 13BT was run at = WOT for=20 many hours at Maximum HP without failure.....and even worse was cycled = back=20 and forth from max torque rpm WOT to max HP WOT, dumped to idle then = back to=20 max HP, etc....on and on and on!  There are hundreds, if not = thousands of=20 combinations of the various components which over hundreds of = thousands of=20 hours of R&D are continuously refined to successfully pass these=20 tests.  I'm certainly not smart enough to know how to improve = upon=20 that.  Perhaps that is my issue?
 
If I'm not mistaken you have written a bit on this and have = endeavored to=20 follow "change as little as possible of the major components" as one = of your=20 guidelines.  Remove the emission components?  Seems = OK!  Change=20 the plug wires, perhaps?  Change the waterpump when we run at = less that=20 max "specified" rpm?  That makes zero sense to me.  Change = the rotor=20 seals/materials/oil pump/waterpump/oil flow.......??, go ahead....but = pain=20 hurts like ____, and my insurance rates go up when an EAA'r crashes = and kills=20 themselves!
 
Pardon my passion in this, but too many "experimenters" are = ruining the=20 possibility of success in the use of low-cost, high production, = automotive=20 based engines in aircraft and it is a shame because there is no = fundamental=20 reason that today's modern automotive engines won't perform admirably, = IF=20 utilized properly.  Work on the installation, not on the basic=20 engine.  Installed in this manner, the accessories will be the = issue, not=20 the powerplant.
 
IMO for your engine.....Best:  buy some new rotors designed = for your=20 housings.  Next best:  Buy three wreck engines with = relatively low=20 mileage ($300/ea. around here) and measure and pick a rotor which meet = Mazda=20 specifications.  Last and probably best and least expensive in = the long=20 run, go purchase an RX8 from a rear-end wreck and put it in, Stock=20 innards/major components.
 
Keep up the super work and communication.  We are counting = on you to=20 be successful.  Your latest escapade really threw water on my = excitement=20 re: my project.  I had hoped you would process fuel like crazy = for a=20 thousand hours while we watched your R&D/durability = results from our=20 shops!!
 
Continued good luck and POR,
 
Doug in Colorado
 
 
 
 
In a message dated 4/14/05 8:35:12 AM Mountain Daylight Time,=20 eanderson@carolina.rr.com writes:
Hi Doug,
 
Some good thoughts and questions, of which I would like to know = the=20 answers to as well.  I believe the reason the experts are = recommending=20 milling the RX-8 rotors for the older seals (when used in the older = rotor=20 housings with peripheral exhausts) is that the RX-8 seal was not = designed to=20 withstand the forces of crossing the exhaust port (in the Peripheral = wall)=20 opening unsupported. Its rather skinny and long.  = Mazdatrix=20 reported the RX-8 seals warped as a consequence of the the hot = exhaust gas=20 blowing over them and primarily the lack of wall support at the = exhaust=20 opening(on the older housings).  The combination of the = additional heat=20 and lack of wall support appears to be more than the 8 seal can = take.
 
However, I am in basic  agreement with you why machine the = rotor=20 when perhaps a new/modified seal is the answer.  I want to = check with=20 Tracy Crook since his seals are reportedly 800% stronger than stock = apex=20 seals to see whether the seals could be machined down/created so = that they=20 fit in the RX-8 rotor  standard apex slot and still be strong = enough -=20 say 300% stronger than stock {:>).  Since they are not made = of=20 typical "gray iron" alloy that the stock and most other seals are = made and=20 chill/case hardened, they may be amenable to machining.
 
Yes, having airports scattered around in just about every = county and=20 sometimes three or more in a county, the geography is much kinder to = engine-out excursions here on the east coast.  Fly High, Glide=20 long!  Better yet, keep running on both rotors.
 
Ed A
 
 
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