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rexjan(at)bigpond.com
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 Posted: Fri Jul 14, 2006 7:16 pm Post subject: Re two strokes |
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I agree with you. But I've heard so many various Rotax stories, that the
motor scared me even before I flew it. I had intended on going another way
right from the start. I just hoped it would survive long enough to find a
suitable cliff. It didn't.
One guy flew one clear across Australia. That's gutsy.
Is that me you are refering to ? I bought my MKIV/582 about 2 years ago in Perth in Western Australia and flew it home to Loxton in Sth Australia. This was written up in an article in our Australian Ultralight magazine.
OK the motor was a nearly new bluehead 582 and had only done 45 hours at the start of the trip. About the same time another guy did an almost identical trip in an Xair with a 582 in it. My point is this two strokes are more than happy doing this sort of thing. Yes two strokes do need a different understanding to a four stroke. However it is only fair that one understands the equiptment they are using before blaming it when it fails. I have had a lot to do with racing two strokes and I love them. If you understand them and treat them right why shouldn't they be more reliable in fact than a four stroke. There is less parts after all. All motors are a work in progress and faults are rectified as they occur and the motor evolves into its current form. This is basically why the Model 99 or Bluehead as we call it 582 is better than the grey head. I repeat all motors evolve or should anyway. I don't think anyone has made a perfect one first time.
Now there is a factor that comes into all this. The 582 is making a lot of power for its weight, capacity and size. So maybe it is stressed a bit more than a larger motor making similar horsepower be it 4 stroke or 2 stroke. However consider that the modern 2 stroke now is typically 85% efficient and it fires every time the piston hits top dead centre, so it will make more power for the same tuning level than a 4 stroke of the same capacity. Don't forget though the 582 is not that highly tuned or stressed. Look at the power it makes as a 583 !
I think a lot of this talk about 2 strokes being inferior is not accurate understanding and knowledge. I put faith in mine to bring me home from Perth and I intend to fly it back there and home again one day. Also in maybe 12 months I will fly it to Alice Springs in the centre of Australia. Am I mad ? You be the judge !
Regards the 532 I don't know a lot about this except heresay but there is a lot of that ! Anyway for what it's worth as it's only my impression the 532 made similar power to the 582 but it was more highly tuned and peaky. Not really suitable for the purpose hence the 582 was born and later developed to what it is today. The old 532 lacks that development. Also such an old motor is likely to have rust spots on needle bearings apart from the bore etc etc. The needle bearings though are the ones that are going to cause very early failure. So all in all I totally agree with the general concensus. Use the 532 for a boat anchor or at least in some situation where a failure is not serious.
If anyone has some cold hard facts against two strokes by all means state them but just generally knocking the 2 stroke without fact is pointless. I ran and owned an electrical business for 30 years before I sold up and retired. Part of that time we sold lawnmowers and we only ever sold one 4 stroke on special request. All the others were 2 strokes. However the general public opinion was against the 2 stroke and this is just the same thing happening here against 2 strokes. Some guys understand 4 strokes but not 2 strokes so yes for them I guess a 4 stroke is the better choice.
Blaming 2 strokes because one had starter gear problems is typical of the problem. Could not the same thing happen to a four stroke ?
OK enough on this subject I'll shut up now I've tried to point this out and by the way I do like the idea of the Geo engine. The one thing I don't like about the 582 is it doesn't like going below 3,000 RPM. I have seen a Geo running dead smooth and I assume it will be more economical. However it won't fit under the cowl as well or weigh the same. Can't win them all.
Rex Shaw
Australia.
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Graeme Toft
Joined: 09 Jan 2006
Posts: 123
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| Posted: Fri Jul 14, 2006 9:05 pm Post subject: Re two strokes |
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Well said Rex and to answer your previous email, things are looking good.
Regards
Graeme
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bmwebb(at)cox.net
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| Posted: Sat Jul 15, 2006 6:30 am Post subject: Re two strokes |
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I guess it was you. I think its an awesome feat, and I’d bet it was a great trip.
I, too, have raced two-strokes, and I do like them very much for that. I recently have had interest in the new four-stroke bikes, but it’s only been in the last few years that they were made competitive. I’ve never had a serious, catastrophic failure on one. And they get beat up pretty hard and abused. But it’s a different application, and I don’t know how it relates. I do know the very small (125cc) motors require a bit more help, but I ran the bigger stuff.
My 582 was ok until the break (aren’t they all?). But my distrust goes deeper than that, and covers the package as a whole. It vibrates terribly, uses a lot of gas, the crank issues, the poorly written manuals, the lack of factory support and acknowledgement of the weak areas, high parts prices, no less than 72 special tools, etc., no local support, etc. My failure was the straw on the proverbial camel’s back for me.
It seems there is a constant thread, on any of several newsgroups, about someone having a problem on their Rotax. I truly believe it is a poor aircraft powerplant. It’s life expectancy is too short, and I never trusted it.
Here’s what I see: with the Rotax, the information available is about fixing problems. When you cruise the Geo threads, it’s about making it better and forward progress. It’s rare that someone writes about a failure. I don’t follow the Subie threads, but I’d guess it’s about the same. Ditto the 912 threads. Yes, occasionally someone hits a problem, but that reasonable for all things. But the 582 stuff is dis-proportionate, from what I see.
Bradley
From: owner-kitfox-list-server(at)matronics.com [mailto:owner-kitfox-list-server(at)matronics.com] On Behalf Of Rex Shaw
Sent: Saturday, July 15, 2006 3:47 PM
To: kitfox-list(at)matronics.com
Subject: Re two strokes
I agree with you. But I've heard so many various Rotax stories, that the
motor scared me even before I flew it. I had intended on going another way
right from the start. I just hoped it would survive long enough to find a
suitable cliff. It didn't.
One guy flew one clear across Australia. That's gutsy.
Is that me you are refering to ? I bought my MKIV/582 about 2 years ago in Perth in Western Australia and flew it home to Loxton in Sth Australia. This was written up in an article in our Australian Ultralight magazine.
OK the motor was a nearly new bluehead 582 and had only done 45 hours at the start of the trip. About the same time another guy did an almost identical trip in an Xair with a 582 in it. My point is this two strokes are more than happy doing this sort of thing. Yes two strokes do need a different understanding to a four stroke. However it is only fair that one understands the equiptment they are using before blaming it when it fails. I have had a lot to do with racing two strokes and I love them. If you understand them and treat them right why shouldn't they be more reliable in fact than a four stroke. There is less parts after all. All motors are a work in progress and faults are rectified as they occur and the motor evolves into its current form. This is basically why the Model 99 or Bluehead as we call it 582 is better than the grey head. I repeat all motors evolve or should anyway. I don't think anyone has made a perfect one first time.
Now there is a factor that comes into all this. The 582 is making a lot of power for its weight, capacity and size. So maybe it is stressed a bit more than a larger motor making similar horsepower be it 4 stroke or 2 stroke. However consider that the modern 2 stroke now is typically 85% efficient and it fires every time the piston hits top dead centre, so it will make more power for the same tuning level than a 4 stroke of the same capacity. Don't forget though the 582 is not that highly tuned or stressed. Look at the power it makes as a 583 !
I think a lot of this talk about 2 strokes being inferior is not accurate understanding and knowledge. I put faith in mine to bring me home from Perth and I intend to fly it back there and home again one day. Also in maybe 12 months I will fly it to Alice Springs in the centre of Australia. Am I mad ? You be the judge !
Regards the 532 I don't know a lot about this except heresay but there is a lot of that ! Anyway for what it's worth as it's only my impression the 532 made similar power to the 582 but it was more highly tuned and peaky. Not really suitable for the purpose hence the 582 was born and later developed to what it is today. The old 532 lacks that development. Also such an old motor is likely to have rust spots on needle bearings apart from the bore etc etc. The needle bearings though are the ones that are going to cause very early failure. So all in all I totally agree with the general concensus. Use the 532 for a boat anchor or at least in some situation where a failure is not serious.
If anyone has some cold hard facts against two strokes by all means state them but just generally knocking the 2 stroke without fact is pointless. I ran and owned an electrical business for 30 years before I sold up and retired. Part of that time we sold lawnmowers and we only ever sold one 4 stroke on special request. All the others were 2 strokes. However the general public opinion was against the 2 stroke and this is just the same thing happening here against 2 strokes. Some guys understand 4 strokes but not 2 strokes so yes for them I guess a 4 stroke is the better choice.
Blaming 2 strokes because one had starter gear problems is typical of the problem. Could not the same thing happen to a four stroke ?
OK enough on this subject I'll shut up now I've tried to point this out and by the way I do like the idea of the Geo engine. The one thing I don't like about the 582 is it doesn't like going below 3,000 RPM. I have seen a Geo running dead smooth and I assume it will be more economical. However it won't fit under the cowl as well or weigh the same. Can't win them all.
Rex Shaw
Australia.
| | - The Matronics Kitfox-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
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occom(at)ns.sympatico.ca
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| Posted: Sat Jul 15, 2006 8:06 am Post subject: Re two strokes |
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On the Saturn group I monitor, nothing but problems and suggestions. On the corvair aircraft group, a raging and impolite arguement about their suitability. On the rotax 912 group, problems. On the subaru group, problems. In the case of the GEO, if there are no problems I'd suspect it's because there are so few of them. I've flown two strokes, seemed ok. My Kitfox has a 582 and 700 hours on the hobbs all on the grey head 582. I expect there are many users with huge numbers of hours without incident. I hope the geo works out for you, but you apparently haven't flown even a minute with it. How about instead of trashing the motors others are using, you get a few dozen real hours and let us know how you make out.
[quote] ---
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