From: "KR-net users group digest" To: "kr-net digest recipients" Subject: kr-net digest: November 24, 1999 Date: Thursday, November 25, 1999 12:17 AM KR-net users group Digest for Wednesday, November 24, 1999. 1. Rotary Engine 2. Kr2s project for sale 3. Re: Rotary Engine 4. Re: Kr2s project for sale 5. RE: Rotary Engine 6. Rotary 7. RE: Rotary 8. RE: Rotary Engine Weight Reduction 9. Rotary:13B 10. More PF Paint Information 11. Re: Rotary:13B 12. Rotary:13B vibration fantasy & cooling comments 13. Re: Rotary:13B 14. Re: Rotary:13B 15. that damn virus 16. Re: Rotary:13B 17. Re: Rotary:13B ---------------------------------------------------------------------- Subject: Rotary Engine From: "Robert Frost" Date: Wed, 24 Nov 1999 5:29:10 X-Message-Number: 1 Having worked with Mazda in racing engine development for about 11 years, with NASA on their single rotor engine, and FMC on a rotary powered electric tank (really! it was cool, but only experimental) I can offer a few things to think about in terms of flying with a rotary engine. The cooling is extremely critical, rotaries are very sensitive to overheating. They will run on either of the two ignition systems, but a major loss of horsepower will be experienced (30-40 hp). It has some serious harmonics associated with certain rpm ranges, and I think a couple of the people converting them are addressing this. We built an engine that was installed in a Long EZ, and at cruise the control cables look like plucked bass guitar strings. The intake and exhaust pulses are very harsh, much more so than in a recip engine, so the airbox needs some flex designed into it. The first time we mounted the engine solid in the race car, almost everything that could got loose and fell off. We ended up cutting pieces out of old tires to isolate some of the vibration. The exhaust system needs to be made of fairly heavy material for longevity, and is LOUDD!!!!!!!!!!!! without a heavy muffler. My RX-7 (170 hp @ 5900rpm) with a stock muffler was miserable to drive on a long trip. You sure couldn't go anywhere without everyone looking to see what sounded like a huge chainsaw. The exhaust at full throttle in a power lean condition will generate 1700 degrees fahrenheit about 16" from the exhaust port. Mazdas have heat shields over most of the exhaust system top and bottom to keep your grass from catching on fire if you pull off the road. They are great engines, simple to build and maintain, and the 13b rotors and eccentric shaft can be lightened about 8-10lbs. The weight savings in a 12A isn't as dramatic, but can be done also. Food for thought Robert Frost Spartanburg, SC rsfrost@bellsouth.net ---------------------------------------------------------------------- Subject: Kr2s project for sale From: "dave tillema" Date: Wed, 24 Nov 1999 5:40:21 X-Message-Number: 2 Well the wife is gone for the holidays, and I'm feeling like cleaning out the garage. Anyone interested in buying my project ?http://www.geocities.com/swooperdave/kr2s.html I will sell this for $5500. , but it needs to be out of my garage a.s.a.p. Thanks Dave ---------------------------------------------------------------------- Subject: Re: Rotary Engine From: "James Nelson" Date: Wed, 24 Nov 1999 09:23:27 -0500 X-Message-Number: 3 Funny thing - I just sold all my misc. Mazda Rotary engine parts on Ebay for $3000. Now you want me to build a KR with a Mazda Rotary. I built a few of them with huge intake and exhaust ports, very high horsepower and giant intake and exhaust systems. They are light for the power, if they are modified. I eventually became satisfied using the stock Mazda turbo engine in the early RX-7, but I can't imagine putting 300 lbs (including cooling, etc...) into a KR airplane. Were you going to direct drive the prop or use a gear reduction? I think the rotary would like to cruise at about 5000 rpm, so you would need to put a 50 lb gear reduction on board, and they like flywheels to be a little heavy - 20 lb at least. James ----- Original Message ----- From: Robert Frost To: KR-net users group Sent: Wednesday, November 24, 1999 5:29 AM Subject: [kr-net] Rotary Engine > Having worked with Mazda in racing engine development for about 11 years, > with NASA on their single rotor engine, and FMC on a rotary powered > electric tank (really! it was cool, but only experimental) I can offer a > few things to think about in terms of flying with a rotary engine. > > The cooling is extremely critical, rotaries are very sensitive to > overheating. They will run on either of the two ignition systems, but a > major loss of horsepower will be experienced (30-40 hp). > > It has some serious harmonics associated with certain rpm ranges, and I > think a couple of the people converting them are addressing this. We built > an engine that was installed in a Long EZ, and at cruise the control cables > look like plucked bass guitar strings. > > The intake and exhaust pulses are very harsh, much more so than in a recip > engine, so the airbox needs some flex designed into it. The first time we > mounted the engine solid in the race car, almost everything that could got > loose and fell off. We ended up cutting pieces out of old tires to isolate > some of the vibration. > > The exhaust system needs to be made of fairly heavy material for longevity, > and is LOUDD!!!!!!!!!!!! without a heavy muffler. My RX-7 (170 hp @ > 5900rpm) with a stock muffler was miserable to drive on a long trip. You > sure couldn't go anywhere without everyone looking to see what sounded like > a huge chainsaw. > > The exhaust at full throttle in a power lean condition will generate 1700 > degrees fahrenheit about 16" from the exhaust port. Mazdas have heat > shields over most of the exhaust system top and bottom to keep your grass > from catching on fire if you pull off the road. > > They are great engines, simple to build and maintain, and the 13b rotors > and eccentric shaft can be lightened about 8-10lbs. The weight savings in > a 12A isn't as dramatic, but can be done also. > > Food for thought > > Robert Frost > Spartanburg, SC > rsfrost@bellsouth.net > > --- > You are currently subscribed to kr-net as: nelsonjjjj@didactics.com > To unsubscribe send a blank email to leave-kr-net-110995W@telelists.com > > ---------------------------------------------------------------------- Subject: Re: Kr2s project for sale From: "dtillema" Date: Wed, 24 Nov 1999 08:57:56 -0600 X-Message-Number: 4 This is a multi-part message in MIME format. ------=_NextPart_000_001A_01BF365A.005525C0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable http://www.geocities.com/swooperdave/kr2s.html ----- Original Message -----=20 From: dave tillema=20 To: KR-net users group=20 Sent: Wednesday, November 24, 1999 5:40 AM Subject: [kr-net] Kr2s project for sale=20 Well the wife is gone for the holidays, and I'm feeling like cleaning = out=20 the garage. Anyone interested in buying my project=20 ?http://www.geocities.com/swooperdave/kr2s.html I will sell this for $5500. , but it needs to be out of my garage=20 a.s.a.p. Thanks Dave --- You are currently subscribed to kr-net as: dtillema@pdq.net To unsubscribe send a blank email to = leave-kr-net-110995W@telelists.com ------=_NextPart_000_001A_01BF365A.005525C0 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
http://www.geocities.com= /swooperdave/kr2s.html
----- Original Message -----
From:=20 dave = tillema=20
Sent: Wednesday, November 24, = 1999 5:40=20 AM
Subject: [kr-net] Kr2s project = for sale=20

Well the wife is gone for the holidays, and I'm feeling = like=20 cleaning out
the garage. Anyone interested in buying my project=20
?http://www.geocities.com/swooperdave/kr2s.html
 I will = sell this=20 for  $5500. , but it needs to be out of my garage=20 =
a.s.a.p.
         &nb= sp;   =20 = Thanks
          &nb= sp;     =20 Dave

---
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To = unsubscribe send a=20 blank email to leave-kr-net-120856G@t= elelists.com

------=_NextPart_000_001A_01BF365A.005525C0-- ---------------------------------------------------------------------- Subject: RE: Rotary Engine From: "Capps Family" Date: Wed, 24 Nov 1999 11:46:24 -0600 X-Message-Number: 5 I'd like to know a little more about "saving weight" on the Rotary. Larry Larry A. Capps Naperville, IL capps@mediaone.net -----Original Message----- From: bounce-kr-net-121858@telelists.com [mailto:bounce-kr-net-121858@telelists.com]On Behalf Of Robert Frost Sent: Wednesday, November 24, 1999 5:29 AM To: KR-net users group Subject: [kr-net] Rotary Engine Having worked with Mazda in racing engine development for about 11 years, with NASA on their single rotor engine, and FMC on a rotary powered electric tank (really! it was cool, but only experimental) I can offer a few things to think about in terms of flying with a rotary engine. They are great engines, simple to build and maintain, and the 13b rotors and eccentric shaft can be lightened about 8-10lbs. The weight savings in a 12A isn't as dramatic, but can be done also. Food for thought Robert Frost Spartanburg, SC rsfrost@bellsouth.net ---------------------------------------------------------------------- Subject: Rotary From: "Robert Frost" Date: Wed, 24 Nov 1999 13:13:25 X-Message-Number: 6 Just for the record, I had been planning a corvair installation for several years now. I don't think that the rotary engine is all that well suited for aircraft use, although there are many of them flying. Some are definitely better than others. The NASA project was a peripheral port single rotor, and the conclusion was that there are many other engines better suited for small aircraft use. The rotary engine behaves similarly to a two stroke engine and is very sensitive to intake and exhaust length. It does, however, have a very flat torque curve which is definitely not similar to a two stroke engine. There was a three rotor engine used in IMSA racing for a couple of years. It ran ok and made good horsepower but was way too expensive for what you got. Robert Frost Spartanburg, SC rsfrost@bellsouth.net ---------------------------------------------------------------------- Subject: RE: Rotary From: Keith Date: Wed, 24 Nov 1999 16:01:59 -0600 X-Message-Number: 7 I raced rotary RX-7's in the mid 80's, and the # one problem I have seen for aviation use is the poor thermal efficiancy which translates to much higher fuel consumption per HP. From my experience they were relativly durable/reliable and very smooth, however, a bit spooky to repair for a non-"rotary" mechanic. Also the weight to HP ratio was not as good as other alternatives available - but would love to see what others think and come up with. I personally will be using a Type IV Porsche/VW Engine - I like the new Flywheel-Side Prop Extension by Steve Bennitt from Great Plains - plan to build mine up to a 2850-3000 and turbo (for altitude compensation only) as I fly high elevation airports in Co. an Ut. L. Keith Farnsworth mailto:kafarn@swbell.net Friends are angels who lift us to our feet when our wings have trouble remembering how to fly. ---------------------------------------------------------------------- Subject: RE: Rotary Engine Weight Reduction From: "Peter Johnson" Date: Wed, 24 Nov 1999 17:44:55 -0000 X-Message-Number: 8 The rotary engine is proving itself to be very well suited to aircraft use. It is possible to take a 13B, or 12A and cut them in half (like a VW), to reduce weight and engine size. It is easily possible to get 85 hp out of a half 13B. As for working on them, they are easier to work on than a conventional engine. There are substantially fewer parts and the assembly/dissassebly procedure is much easier to do. Anyone interested in the rotary engine and its use in aircraft should check out the following very well behaved and enlightening newsletter ' rotaryeng@earth-link.net ' mailto:pjohnson@voyageur.ca ---------- ---------------------------------------------------------------------- Subject: Rotary:13B From: "Capps Family" Date: Wed, 24 Nov 1999 17:50:01 -0600 X-Message-Number: 9 It is clearly evident by this response (*see below) that you have never rebuilt a rotary, but you find yourself qualified to respond on how hard they are to rebuild. For those enquiring minds; The Mazda 13B design is inherently more reliable than reciprocating engines in that there are fewer moving internal parts. There are no Cam shafts, valves, valve springs or keepers, no valve rocker arms, no connecting rods or piston wrist pins. Furthermore, there are a number of other features which contribute to reliable and safe operation. The rotors which revolve on an eccentric shaft (crankshaft) are of a iron alloy while the housing ( or chamber) they rotate in is of an aluminum alloy. Loss of coolant and resulting overheating resulting in the aluminum housing expanding faster than the iron rotors, this increases the clearances between moving parts (rotor) and stationary parts (the housing) which greatly reduce the potential for engine sizing due to over heating which can quickly occur with loss of coolant in reciprocating engines.( If fact, one installation of a 13B in an aircraft did lose all coolant and while the temperature red-lined, the engine continue to function until the pilot could land. A subsequent tear down and inspection of the engine revealed no damage other than a number of rubber seals were damaged due to the excess heat and required replacement.) The Wankel engine has been used in automobile race events for a number of years and has a wide spread reputation for durability under extreme operating conditions. The Wankel engine is inherently smoother than a reciprocating engine in that there are no linear to rotational translations as exists in a reciprocating engine. This greatly reduces vibration and inertial loads caused by pistons reversing direction in a cylinder several hundred times a minute. Additionally, the power pulses are more frequent, but of a much lower magnitude that a typical four cylinder aircraft engine. This reduces airframe and component fatigue effects and also reduces pilot and passenger fatigue. It also lowers the magnitude of the propeller torsion response to the power pulses. A number of studies on the predicted TBO of the Wankel in aircraft use have been done by industry and research centers. While the upper limit estimated has varied, depending on a number of conditions, the consensus appears to be that there is no reason to expect any less than the typical 2000 hour TBO of a certified aircraft engine and some indications are that it could be as much as 4000 hours. Only actually aircraft usage will provide the ultimate answer. But, given a first class remanufactured engine costs from $1600-$3200, the Wankel adaptation is cost effective even if the TBO turns out to be only 1000 hours. -Edward L. Anderson (http://www.flash.net/~donmack/mazda/information.html) Real World Solutions Inc. was formed for the purpose of developing cost effective information and products for converting the Mazda rotary engine for aircraft use. The rotary is uniquely qualified for this use due to its high power-to-weight ratio and reliability at high power settings. -Tracy Crook http://www.rotaryaviation.com/ In summary, I believe the engine has a number of inherently desirable features and benefits for aircraft use. The adaptations to make it suitable for aircraft use have been carefully thought out and failure modes thoroughly examined. I have designed the subsystems for fail-safe and redundancy, wherever feasible. I have spend over 18 months developing and testing the engine and its subsystems. I will conduct an extended taxi and flight test program to further ensure its reliability and safety. I believe, I have prudently and carefully assessed the benefits and drawbacks. I have placed safety and reliable operation at the top of any design decision. I am confident that safe operation of the aircraft with this power plant has not been compromised. An individual in Florida, Tracy Crook has over 500 hours on an RV-4 powered by a Mazda Wankel 13B engine. Tracy has produced an excellent "conversion" manual for the 13B and has a newsletter on the engine. There are several others such as PowerSport Inc. ,whom have essentially design a Wankel Rotary engine from the ground up for aircraft use and have achieved extraordinary performance with the engine mounted in an RV-3. To my knowledge, there have been no accidents or engine failures resulting in accidents from their use of the Wankel Rotary engine. Larry -----Original Message----- From: bounce-kr-net-121858@telelists.com [mailto:bounce-kr-net-121858@telelists.com]On Behalf Of Keith Sent: Wednesday, November 24, 1999 4:02 PM To: KR-net users group Subject: [kr-net] RE: Rotary *I raced rotary RX-7's in the mid 80's, and the # one problem I have seen for aviation use is the poor thermal efficiancy which translates to much higher fuel consumption per HP. From my experience they were relativly durable/reliable and very smooth, however, a bit spooky to repair for a non-"rotary" mechanic. Also the weight to HP ratio was not as good as other alternatives available - but would love to see what others think and come up with. I personally will be using a Type IV Porsche/VW Engine - I like the new Flywheel-Side Prop Extension by Steve Bennitt from Great Plains - plan to build mine up to a 2850-3000 and turbo (for altitude compensation only) as I fly high elevation airports in Co. an Ut. L. Keith Farnsworth mailto:kafarn@swbell.net Friends are angels who lift us to our feet when our wings have trouble remembering how to fly. --- You are currently subscribed to kr-net as: capps@mediaone.net To unsubscribe send a blank email to leave-kr-net-110995W@telelists.com ---------------------------------------------------------------------- Subject: More PF Paint Information From: "Bernard A. Wunder" Date: Wed, 24 Nov 1999 17:36:45 X-Message-Number: 10 KR-Paint netters, One of the guys in our EAA chapter(Bernie Wilder) has "re-invented" the painting process working with PolyFiber while painting his Pulsar. As he told us, there had to be a better way than the never ending prime, sand,prime, sand, and paint and then sand and prime some more.....He started experimenting using paint rollers (he took a very scientific approach to the problem) and found out how many layers it would take and how much sanding was needed(very little for the prime coats). We had a chapter meeting at his home and his Pulsar looked like it had a procelain smooth finish. He also found out that you could mix the UV protector with the primer. The company has basically taken his ideas and incorporated his processes (they did name the process after him and if you were at Oshkosh during the composite painting forum, they gave him all the credit). I have attached a few of his e-mails with his permission that discuss some of his thoughts. Bernie Wunder Lexington Park, MD bwunder@tqci.net kr2s plans in hand .------------------------------------ Bernie Wilder E-mails: Smooth Prime usually causes people no problem, mainly because it is easy to sand down smooth after you get some unevenness. TopGloss is different. You must spray differently than you do the paints with a flash solvent. You must use light coats,,,I put on four light coats and then color sand and polish. ((You must color sand and polish this stuff if you have the level of skills that I have. Maybe a professional who has mastered water bornes could get a good enough final coat,,,I can't.)) Also, Top Gloss works best with a high pressure system. Atomizes the paint better, and if you don't get it atomized, you can't control it. I had never sprayed the flash solvent stuff, so I didn't have to unlearn an old technique. Just learn the new one. If they try to apply water bornes like solvent based paints, they will fail. Guys better learn to use the water bornes because it won't be long before you won't be able to ship the solvent based stuff through normal channels - - like UPS, motor freight, etc. They require shipment as hazardous matrerials now,,,wait until it gets tighter. The military uses a lot of water bornes now and I am told will eventually require all military painting to be done with the environmentally friendly water born paints. --------------------- Another tip from Bernie Wilder: > After applying TopGloss and letting it set for a week, I began wet color > sanding by hand. A bucket of water, a sponge, rubber sanding block and > away we go........After a bit I thought there must be a better way. > > I bought a DeWalt palm sander. A bucket of water, a sponge, a DeWalt sander > and away we go........It worked fine. > > BUT>>>>>>The sander burnt out in short order. > > I visited the local Mom and Pop auto painting shop and asked how they > color sanded. > > A "Windex" spray bottle, an air powered sander and away they > went........Don't put the water on with a sponge they said, just spray on > enough with a windex bottle to keep it wet. Works as well and less mess, > they said. > > I didn't want to go the air powered route so I took another look at the > burnt out palm sander to see what went wrong. I thought maybe that if I > plugged the holes where the sander sucks off the dust, maybe the water > wouldn't get into the bearings of the sander and it would hold up. > > I bought another DeWalt sander and plugged the holes with silicon caulking > compound. I got an old Windex bottle, filled it with water and went at it > again. As the Egyptians say, "NooooooooooooProblem". The sander has held > up. Color sanding is easy, though it takes a little time. It is worth it! ---------------- and other one: It is conventional wisdom that all fillers for composites settle over > time,,,PolyFiber's UVSmooth Prime amongst them. Polyfiber is working on > alternative material to minimize this but they are not available yet, nor > probably in the near term. > > How much the settling of the filler ultimately shows is relative to the > differential thickness of the filler on the surface of the panel. How fast > they settle is still an open question. I am confident that the speed of > setling is not linear but that it settles fast at first and the rate then > decreasses and, if plotted, becomes an asymptotic line. Heat accelerates > the settling (actually shrinking), but you can't put your plane in an 150 > degree oven over nite. If applying just UVSP, I would wait at least two > months after applying UVSP before sanding it down for the top coat. > > My advice has been to prime early and don't try to rush it. > > I found myself in a position where I wanted to rush it with my wings and > tried an alternative material that worked - also made by PolyFiber,, the > Superfil that we all use to fill larger holes. ((Superfil is very stable > and doesn't shrink.)) > > I tried several samples to come up with the following proceedure: > > I applied a layer with a three inch putty knife, forcing it into the > surface with the blade held quite flat against the surface. I didn't try to > wipe it off the surface, just force it in and left a layer about 1/8" thick > on the surface. I went right back over the surface with the putty knife > with the blade held at about a 45 degree angle and wiped all off the > surface that I could. I did one three inch strip at a time. I found it > important to move the knife slowly for both the initial coating and when > wiping the first layer off the surface. It doesn't look as if there is much > left on the surface,,,but if you really pushed it into the surface on the > first application, there is enough. > > I let it dry overnite and then applied a guide coat of black lacquer. I > sanded the surface down smooth using 80 grit paper. ((Yes, that is pretty > rough stuff.)) I was careful to not sand too much. After sanding it looks > as if there is even less material on the surface. There was enough. In > fact, some of the Superfil seems to go into the surface of the cloth fibers > themselves giving you an overall harder surface. > > I applied four sprayed coats of UVSP and waited to see if I was going to > get any differential settling that would show the pattern of the composite > cloth. ((The initial settling will show up in a week or so.)) > > After a month, the surface has remained free of any settling that shows a > cloth pattern,, indicating that the Superfil left me with a flat surface. > > Disadvantage - it is more work than rolling or spraying on six coats of > UVSP. > > Advantage - I don't have to wait two months to be sure the UVSP has > finished settling. ------------------------------------------ and another! You can do it ! ! I have applied the Top Gloss using > HVLP, high pressure, roller and brush. Forget roller and brush. High > pressure system works better than the HVLP system for the old Top Gloss. > This is how I painted my fuselage, tail surfaces and flaps ands ailerons. I > will be applying the new TopGloss in about a week to my wings and will try > it with both high pressure and HVLP systems and can give an oppinion then. > Polyfiber says the new TopGloss sprays better with a high pressure system > than a HVLP system. They also say it is a little thicker, so I want to > determine which is best for myself. All other things being equal, I prefer > a HVLP system. Less over spray hence fewer particles flying aroung the > workshop and it uses 25-30% less paint. > > Problems - Only problem I have heard of is that if the Smooth Prime isn't > given enough time to completely dry and settle, the weave pattern will show > up in the surface of your TopGloss when it does. How long has the Smooth > Prime been on the plane?????????? > > You must color sand and polish to get a good finish. After doing that, the > finish is deep and a water surface. Like a hand rubbed finish on a show > car. But, you have to color sand and polish. I use a power palm sander and > power polisher and it goes quite well. > > To overcome the settling, Polyfiber says to put on the TopGloss, don't > color sand and polish for about a month or two to give the Smooth Prome a > chance to settle. They say to go fly off your 40 hours, then color sand and > polish. I prefer to let the Smooth Prime settle for a month or so before > putting the Top Gloss on. What you do, I guess, depends upon where you are > in the process. If you just put the Sandwich on, you probably don't want to > wait a month or so to do the final sanding and apply the TopGloss. If you > follow their advise, put on an extra coat or so of TopGloss because in a > couple months when you color sand to get the weave patptern out, you willll > be removing some of the Top Gloss. > > Incedently, all primers and fillers settle, even the ones that are solvent > based. It doesn't make any difference what kind of top coat you use, or who > applied it, if the underlying materials settle into the weave, you will see > weave pattern in the surface of the paint. ((Even under a $5,000 paint > job.)) > > I recommend doing it yourself and the use of TopGloss. Saves a lot of > money. You'll get a lot of satisfaction out of doing it yourself. AND, you > will be one of the few who can say," I built it and I even painted it!". > > You can do it in your garage. You will want to be able to vent air from > your garage because even with the HVLP system, you will get more particles > in the air than you will want to let settle on the finish. ((Although if > you get a lot of particles settling on the paint, color sanding and > polishing takes care of them.)) I used a painters resperator, the kind that > have two round filters on the side of the mask. > > To clear the air out of a windowless garage, I raised the garage door the > heighth of my fans, I used two window fans, put them on one side of the > door, blocked off the center section and left an open area on the other > side of the door as an input. The air came in one side, went around in a > circle in the garage and out the other side of the door. Worked fine. > > I wouldn't recommend painting outside unless the weather is hot, low > humidity, there is no wind, and there is no dust or pollen in the air. If > you find such a place, let me know, I want to move there. Some people have > built temporary tents outside out of 2X2s, covered the framework with > plastic and stuck a fan or two in openings. > > Hope the above helps. ---------------------------------------------------------------------- Subject: Re: Rotary:13B From: Mike Mims Date: Wed, 24 Nov 1999 18:19:27 -0800 (PST) X-Message-Number: 11 --- Capps Family wrote: > The Wankel engine is inherently smoother than a > reciprocating engine in that there are no linear to rotational translations as exists in a reciprocating > engine. This greatly reduces vibration and inertial > loads caused by pistons reversing direction in a cylinder several hundred times a minute. It also lowers the magnitude of the propeller torsion response to the power pulses. > >>>>>A number of studies on the predicted<<<<< I don't know Larry, it sounds like you are quoting a lot of theory and "predictions". The fact is that a rotary engine is not easy to make work in an airplane. As far as less vibration and less torsional vibration that's totally untrue from what I have read. I have also read (Sport Aviation, Kitplanes, etc.) that the rotary is almost impossible to cool. Not only that they are considered gas hogs as far as HP per gallon of fuel consumed Several years ago some of the big issues when using a rotary in an airplane are, gas consumption, vibration (these things do vibrate, why do you think the rear view mirrors on the last RX7 were liquid dampened?), heat and a HUGE torsional vibration issue at certain RPMs. I don't know maybe the aviation rotory has come a long way in the last 5 years but these were the issues back then. Another vibration note: a friend of mine had a RX7 turbo and at certain RPMs the noise was horible and your teeth would feel like they were chattering because of the harmonics (thats vibration however you want to look at it). There was a company called Duncan Aviation (I thin it was Duncan) back in the 80s that sold a ton of rotary conversions and for some odd reason could not deliver. Seems that just couldn't get it to work and they were in the business. On the other hand its always nice to see someone want to jump on a horse and take the lead. Knock yourself out and let us know how it works. I will stick with my Lycasaurous and its proven history. __________________________________________________ Do You Yahoo!? Thousands of Stores. Millions of Products. All in one place. Yahoo! Shopping: http://shopping.yahoo.com ---------------------------------------------------------------------- Subject: Rotary:13B vibration fantasy & cooling comments From: "James Nelson" Date: Wed, 24 Nov 1999 21:53:25 -0500 X-Message-Number: 12 Look at the mechanical system of the Wankel engine to understand the vibration or lack thereof. The fact is that the Wankel Rotary engine, when balanced correctly, will have NO vibration or harmonics of any order to deal with, unlike a piston engine which CANNOT be balanced perfectly, no matter how much you fool with it. Exhaust is another issue. In practice, you can sit in an RX-7 and rev it to 7000 rpm and it is smooth all the way up. If you can't keep the mirrors from vibrating on a particular model of car, then there are problems OTHER THAN those inherent to the engine's rotating masses. When the rotary is overheated badly, what happens is the rotor housings crush slightly, and when they cool down, they are too narrow, and thus need replacing. I have measured this effect in the past, and thrown out beautiful looking housings due to overheating. In practice, the engine runs in the overheated state, sometimes with reduced power due to blowby or whatever, but the rotor housings need to be replaced. Remember, the Mazda Rotary has oil cooling for the rotors, which is VERY significant, AND water cooling for the rotor housings and end housings, etc... I have built and re-built many rotary engines and spent countless hours studying the engine theory and design. Furthermore, I have a degree in Mechanical engineering, so I understand the complexities of vibration theory. James ---------------------------------------------------------------------- Subject: Re: Rotary:13B From: WilliamTCA@aol.com Date: Wed, 24 Nov 1999 22:51:55 EST X-Message-Number: 13 Friends, All these hot words about a motor which will not even fit in a KR! My ten years of experience with alternative engines tells seems to say that both sides of this discussion have many valid points. Guys Like Tracy have logged many hours with these motors, and the Ross family has a huge amount of time on one. Clearly they can be made to work in planes. To be fair, I think that one of the founders of Power Sport lost his life in an engine failure. This is not a condemnation, just a factual note. The motor does present unique challenges to installation that other motors do not. Reductions, cooling, exhst. to name a few, but guys like Tracy and Mr. Atkins have done a lot of work to teach people how it can be done. You wont be starting from scratch, but its still not the simplest installation. All of this seems academic because the inexpensive rotaries which go with the low cost KR concept, are all too heavy for the plane. The commercially avail. Small rotary A/C motors, i.e., Norton, Midwest, Atikin, are all very expensive motors for a KR. Like all motors, Some people will love them without good reason and some people we hate them without good reason. Most people will find it technically interesting, but for one reason or another use something else. The extremes of this will never persuade each other to change mindsets. Live and let live, and lets get back to topics closer to the KR. Thanks William ---------------------------------------------------------------------- Subject: Re: Rotary:13B From: Mike Mims Date: Wed, 24 Nov 1999 20:12:56 -0800 (PST) X-Message-Number: 14 --- WilliamTCA@aol.com wrote: > Friends, > > All these hot words about a motor which will > not even fit in a KR!>>> Heck I wasn't even aware that it was too heavy for a KR. How much does a 13b weigh? For some reason I was under the impression it weighed no more than a O-200 (220lbs or so). But now that I think about it most of them are mounted in larger aircraft than the KR. I am off to the garage to work on my rudder. __________________________________________________ Do You Yahoo!? Thousands of Stores. Millions of Products. All in one place. Yahoo! Shopping: http://shopping.yahoo.com ---------------------------------------------------------------------- Subject: that damn virus From: "Christopher Stewart" Date: Wed, 24 Nov 1999 23:07:09 -0500 X-Message-Number: 15 im getting everything twice is it the virus happy99? and how do i get ride of it? Christopher Stewart cstewart@kvinet.com ---------------------------------------------------------------------- Subject: Re: Rotary:13B From: Laheze@aol.com Date: Wed, 24 Nov 1999 23:45:22 EST X-Message-Number: 16 Mike, I am familiar with Duncan Engines ( out of Oklahoma ) the guy was a bigger ( body) version of Jim Bede, lots of promises and big ideas and eager to take your money while not delivering the product. I remember when he came to our Dallas Chapter 168 Eaa meeting and had everyone there ready to throw away their Lycomings and buy his system. Well several did and only one got his engine and that was because he stayed in Oklahoma until he was reluctantly given his. The last I knew the fellow that got the engine did a lot of modifying to what he got and was putting it in a Varieze, that was 10 or 15 years ago and I have no idea what ever happened to that experiment. I think the guy selling was Jim Duncan. Larry Howell laheze@aol.com ---------------------------------------------------------------------- Subject: Re: Rotary:13B From: "Capps Family" Date: Wed, 24 Nov 1999 23:15:01 -0600 X-Message-Number: 17 Mike, I absolutely respect your opinions, and I agree with you that the Rotary Engine is very Noisy; I just ask that you view and read the websites I included in my last post before anyone hammers an idea without first-hand knowledge. Blue Skies; Larry -----Original Message----- From: bounce-kr-net-121858@telelists.com [mailto:bounce-kr-net-121858@telelists.com]On Behalf Of Mike Mims Sent: Wednesday, November 24, 1999 8:19 PM To: KR-net users group Subject: [kr-net] Re: Rotary:13B --- Capps Family wrote: > The Wankel engine is inherently smoother than a > reciprocating engine in that there are no linear to rotational translations as exists in a reciprocating > engine. This greatly reduces vibration and inertial > loads caused by pistons reversing direction in a cylinder several hundred times a minute. It also lowers the magnitude of the propeller torsion response to the power pulses. > >>>>>A number of studies on the predicted<<<<< I don't know Larry, it sounds like you are quoting a lot of theory and "predictions". The fact is that a rotary engine is not easy to make work in an airplane. As far as less vibration and less torsional vibration that's totally untrue from what I have read. I have also read (Sport Aviation, Kitplanes, etc.) that the rotary is almost impossible to cool. Not only that they are considered gas hogs as far as HP per gallon of fuel consumed Several years ago some of the big issues when using a rotary in an airplane are, gas consumption, vibration (these things do vibrate, why do you think the rear view mirrors on the last RX7 were liquid dampened?), heat and a HUGE torsional vibration issue at certain RPMs. I don't know maybe the aviation rotory has come a long way in the last 5 years but these were the issues back then. Another vibration note: a friend of mine had a RX7 turbo and at certain RPMs the noise was horible and your teeth would feel like they were chattering because of the harmonics (thats vibration however you want to look at it). There was a company called Duncan Aviation (I thin it was Duncan) back in the 80s that sold a ton of rotary conversions and for some odd reason could not deliver. Seems that just couldn't get it to work and they were in the business. On the other hand its always nice to see someone want to jump on a horse and take the lead. Knock yourself out and let us know how it works. I will stick with my Lycasaurous and its proven history. __________________________________________________ Do You Yahoo!? Thousands of Stores. Millions of Products. All in one place. Yahoo! Shopping: http://shopping.yahoo.com --- You are currently subscribed to kr-net as: capps@mediaone.net To unsubscribe send a blank email to leave-kr-net-110995W@telelists.com --- END OF DIGEST --- You are currently subscribed to kr-net as: johnbou@ipinc.net To unsubscribe send a blank email to leave-kr-net-110995W@telelists.com