codensr Posted April 28, 2003 Share Posted April 28, 2003 I've just order my plans last week for the mrk4,after a year of procastinating. I was reading Al Wicks article on his cozy with a Suberu and a constant speed prop. Just like to know anyones thoughts on a light weight constant speed prop with a rotory 13b on the cozy? I sure Nat would discourage this change. Quote CODEN SR, Builder MK IV #1146 Link to comment Share on other sites More sharing options...
Aaron Posted April 29, 2003 Share Posted April 29, 2003 http://cozyaircraft.com/forum/showthread.php?s=&threadid=248 I've thought about it myself, just be sure you know what the maintenance routines are, it would suck to die from your experimental aircraft, even worse when you think about wiping out your whole family...or someone elses. Quote Link to comment Share on other sites More sharing options...
dust Posted April 29, 2003 Share Posted April 29, 2003 a little negative are we tonight. my buddy has an elec adjustable prop on his bonanza and that dam prop is nearing 50 years old. I fail to see why you, oh my turboe, has so much fear of a elec adj prop I, on the other hand, am petrified of auto engines in airplanes, he he he Quote maker wood dust and shavings - foam and fiberglass dust and one day a cozy will pop out, enjoying the build i can be reached at http://www.canardcommunity.com/ Link to comment Share on other sites More sharing options...
John Slade Posted April 29, 2003 Share Posted April 29, 2003 Congratulations on ordering the plans. The fun is about to begin! As for the prop - I've heard enough for me to stay away from the IVO. By the time you're ready, maybe Paul Lamar (rotary newsletter) will come through with the constant speed prop he and a few like minded Wanklers are developing. I believe they're almost at the prototype stage. In the meantime I'll be using a beautifully carved chunck of wood from Performance Props. Quote I can be reached on the "other" forum http://canardaviationforum.dmt.net Link to comment Share on other sites More sharing options...
dust Posted April 29, 2003 Share Posted April 29, 2003 Who said anything about an IVO prop? Quote maker wood dust and shavings - foam and fiberglass dust and one day a cozy will pop out, enjoying the build i can be reached at http://www.canardcommunity.com/ Link to comment Share on other sites More sharing options...
John Slade Posted April 29, 2003 Share Posted April 29, 2003 Aaron Quote I can be reached on the "other" forum http://canardaviationforum.dmt.net Link to comment Share on other sites More sharing options...
John Slade Posted April 29, 2003 Share Posted April 29, 2003 >I, on the other hand, am petrified of auto engines in airplanes But you'll be happy with something that was designed 40 years ago, parts of which were probably manufactured 30 years ago, is inefficient, noisy, rattles you're teeth, and has hundreds of moving parts any one of which can spoil you're day, not to mention empty you're wallet? Think of the Rotary this way - It's an ideal airplane engine that someone put in a car by mistake. There are 18,000+ RX8's on their way to the US as we speak. Rugged as hell, 5 moving parts none of which can break, 250HP out of the box normally aspirated, and lighter than an IO360. Factory new engines are already appearing for $11,000 or so. They'll get cheaper rapidly. People are already swinging their aviation related products toward it. Tracy Crook has announced a 2.85 ratio redrive designed for it. If I were just starting a Cozy the engine choice would be a no-brainer. But that's just me..... Quote I can be reached on the "other" forum http://canardaviationforum.dmt.net Link to comment Share on other sites More sharing options...
dust Posted April 29, 2003 Share Posted April 29, 2003 you mean that BOLD print at the start of his post that I didn't bother to read, sorry. Size twelve fits loosly now Quote maker wood dust and shavings - foam and fiberglass dust and one day a cozy will pop out, enjoying the build i can be reached at http://www.canardcommunity.com/ Link to comment Share on other sites More sharing options...
Aaron Posted April 29, 2003 Share Posted April 29, 2003 John- as for the Renesis it's 250HP at 8500RPM. Assuming that 2.8 redrive is to turn a prop at 2400 rpm, you're looking at 6700 rpm on the engine. Considering this engine's dyno plot you're talking about 200 HP (approx). Still a great engine for this application, don't get me wrong- I'm just the numbers guy. Dust-Sorry I thought Al was driving an IVO prop, my bad. I originally was looking at IVO's adjustable stuff-Adjustable makes sense to me, but the price of most constant speed props doesn't. And then seeing about that family who died due (presumably) to improper bolt torque...Well lets just say it's one story I'm not sharing with my wife, but I'll keep in the back of my head next to my skydiving skills. As for props- I've go PLENTY of time before I worry about this, plenty of time to wait and see how Lamar's experiment goes. Quote Link to comment Share on other sites More sharing options...
CBarber Posted April 29, 2003 Share Posted April 29, 2003 I hope you don't mind if I steal it......a rotary is a great aircraft engine someone put in a car by mistake. In the words of Alf "HAH" I am also glad to see your comments on the Renesis as it is what I hope to put in my Velocity. I hope they are not quite 10K (still way better than certified). Leon from Oz was saying about 10k Aus dollars which he stated is about $6500 US. Also, I will be keeping my eyes and ears open at wrecking yards. All the best, Chris Houston Quote Christopher Barber Velocity SE/FG w/yoke. Zoom, zoom, zoom. www.LoneStarVelocity.com Live with Passion... Link to comment Share on other sites More sharing options...
John Slade Posted April 29, 2003 Share Posted April 29, 2003 Aaron - you're right about the HP numbers, except that removing the emissions stuff and some minor tweaking, should get you all the power you can use even at prop rpms. I'm expecting 280HP from my ported turbo 13B REW. At least that's what my prop was cut for. With that much power you dont need a constant speed prop. You take off and climb with brute force, then cruise at a higher top speed with a fixed pitch cruise optimized prop. Greg Richter described take-off in his 13B Cozy as like "setting off in a Porche". I understand he gets airborne in < 1000 ft. Probably less now he's putting a jet in the thing. He did some time in a Lyc powered COzy after flying his plane a few times. He told me he aborted his first take-off thinking there was something wrong with the engine Yes, Chris - you're right about the $au figure. I forgot about the conversion. Also keep in mind that a bad noise from the engine CANNOT cost more than $6500 or so. Bad noises from a Lcy can be $14,000 noises. I know. I was that soldier. The other point about bad noises is that a rotary will invariably get you home without failing catastrophically. No conrods through the cylinder walls, no burnt or swallowed valves, no pushrods to bend etc. etc. The big trick with the rotary, or any engine conversion, is in the periforals - fuel or ignition problems will stop ANY engine in its tracks. These are proven installations with a Lycoming. Much less so in any conversion. This is why I'm concentrating on redundancy and testing in these areas. Quote I can be reached on the "other" forum http://canardaviationforum.dmt.net Link to comment Share on other sites More sharing options...
chuckthedog Posted April 29, 2003 Share Posted April 29, 2003 Are all you number crunchers crazy or just plane stupid? 1. 280 HP turbo Mazda. Come on thats brake HP not constant. Nobody runs a car motor at top RPM all day, or even a half day. 2. The most efficent reduction known to man will eat up 30% of your power. No brag just fact. 3. Props, why don't you find a run out Air Force unmaned recon pusher. Take the engine and prop, and use that. I am pertty shure those guys tried one or two things before they said Mazda's suck, Rotax rules. And last but not least. Just build the Plane for now. And stop trying to reinvent the wheel. I know this sounds testy, and you are correct. If you guys would just build, and shut up you could be a couple of chapters farther along than you are now. Enough said. I gotta go fly my Lycoming powered,Catto proped Long someplace for a hamberger. I can afford to do this cause my engine and prop havent cost me all my hamburger money. Best of luck on your projects:D Quote If the phone don't ring. It's me Link to comment Share on other sites More sharing options...
ekisbey Posted April 29, 2003 Share Posted April 29, 2003 Originally posted by chuckthedog find a run out Air Force unmaned recon pusher. Take the engine and prop, and use that. If I had 43 million dollars to spend on my aircraft (what we pay General Atomics of southern California to build each RQ-1 Predator UAV system), I wouldn't use a rotary either. I damn sure wouldn't use a Rotax. Especially not on a Cozy. Assuming I end up using a rotary, I have no intention of re-inventing the wheel. I'm building the plane 'cause I'm sick of wheels. I want an aircraft so I can get there quickly, comforably, and safely. The rotary looks like it could be the answer, even considering the engineering problems that confront it. Piston engines have a full century of refinement behind of them, but they had their own problems at the start. They still have problems. The rotary is still in it's infancy in comparison. If there are still problems that exist in engineering a rotary into an aircraft application, then I'll join these guys in hammering them out when the time comes, but nobody's re-inventing anything. If there wasn't serious potential in the rotary engine, it wouldn't be recieving a fraction of the attention it's getting now in the experimental arena. And if the homebuilders and experimenters are playing with them, then you can count on the GA manufaturers to be watching very closely, letting us work out all the bugs and proof-of-concept footwork. How long will it be before a company such as Lyc or TCM has it's name stamped on a rotary? Maybe never, but the folks in this topic don't seem to be waiting. I wonder if maybe they know something you don't? Quote Evan Kisbey Cozy Mk IV plans # 1114 "There may not be any stupid questions, but I've seen LOTS of curious idiots..." Link to comment Share on other sites More sharing options...
Aaron Posted April 29, 2003 Share Posted April 29, 2003 Nobody runs a car motor at top RPM all day, or even a half day. We're talking about running the engines at 75-80% not redline. These engines are nothing like auto piston engines so drawing parallels there is about as effective as comparing your engine to a rotary. If you wish I can cite several examples of Mazda engines flying trouble free for 100's (and 1000's) of hours in experimental aircraft. 2. The most efficent reduction known to man Hmmn, 30% is a bit on the high side, even auto transmissions have drive line losses of 10-15%, and that's after going through several gears and the differential. Can you state a reference for your "fact"? I know this sounds testy, and you are correct. Well since I'm the only "Number Cruncher" here, I guess this post is directed at me:) but I really don't know why your "testy" with me. Perhaps you think I should be farther along on the plane. Considering I haven't selected a plane yet to build, I've got quite a ways to go. Yet even at my limited experience I realize that some people build to fly, some build to learn. I could be farther along if I "build and shut up", but then I'd be just as ignorant as when I started. Me, I'm in it for the learning, so I'll take my time, if thats OK with you. I look forward to learning more from you when you get back from you hamburger run. Quote Link to comment Share on other sites More sharing options...
dust Posted April 29, 2003 Share Posted April 29, 2003 when i was a youngster, my buddy had a vw bug, and on the freeway he ran it at full, all out for hours at a time, you had to to go the speed limit up a hill or against the wind, thats the only experience I can personally remember where i saw an auto engine perform as though it was an airplane engine. Quote maker wood dust and shavings - foam and fiberglass dust and one day a cozy will pop out, enjoying the build i can be reached at http://www.canardcommunity.com/ Link to comment Share on other sites More sharing options...
JakeC Posted April 29, 2003 Share Posted April 29, 2003 Are all you number crunchers crazy or just plane stupid? 1. 280 HP turbo Mazda. Come on thats brake HP not constant How are Lycoming Horsepower ratings measured? I'm asking because I've always assumed (possibly incorrectly) that most if not all engine manufactures listed their performance in Max HP not continuous. Is this not the case with Lycoming and Continental? codensr, If you find some good info on constant speed props from somewhere other than this thread could you let me know? I'd love to hear about it. Jake Quote www.homebuiltairplanes.com Link to comment Share on other sites More sharing options...
No4 Posted April 29, 2003 Share Posted April 29, 2003 Ahh, the good old my engine is better than your engine argument. I used to sit in an auto day and night running 75% power for hours on end, that engine never missed a beat whether it was 140', blowing a hurricane, or I was scraping frost of the windshield. The only trouble is that particular Cummins produces 750 hp and the weight might be a bit much for the Cozy. I don't think some of the figures about gearbox power losses are quite right. If it is done right 5-15% max. If anyone's planning on using a Subaru, there's a company here www.sub4.co.nz , but I don't know about pushers. Back to the original thread, Are there any pusher constant speed propellor units about, electric or hydraulic? Quote The Coconut King Link to comment Share on other sites More sharing options...
marbleturtle Posted April 29, 2003 Share Posted April 29, 2003 Hey John, am I allowed to smack Chuckie or am I still in the dog house?!?!?! Quote This ain't rocket surgery! Link to comment Share on other sites More sharing options...
dust Posted April 30, 2003 Share Posted April 30, 2003 sure rear engine of the 337 is a pusher Quote maker wood dust and shavings - foam and fiberglass dust and one day a cozy will pop out, enjoying the build i can be reached at http://www.canardcommunity.com/ Link to comment Share on other sites More sharing options...
John Slade Posted April 30, 2003 Share Posted April 30, 2003 MT, You're still in the dog house. We're all waiting for some intelligent contributions or even questions. The one line glib comments can be funny, but they dont really contribute much. My 2 c Quote I can be reached on the "other" forum http://canardaviationforum.dmt.net Link to comment Share on other sites More sharing options...
marbleturtle Posted April 30, 2003 Share Posted April 30, 2003 Oh... Sorry. Quote This ain't rocket surgery! Link to comment Share on other sites More sharing options...
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