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Magnum vs O.S.

Old 05-24-2016, 08:53 AM
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gunnarmm
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Default Magnum vs O.S.

I am about to start construction on a BTE Venture 60 (think Sig Four Star 60) and I initially intended to install a two stroke OS .65 AX. I noticed on the Tower Hobbies site that Magnum engines are about half the cost of comparable OS engines, and that for the price of a O.S. 65 AX I could nearly buy a Magnum XL 70 four stroke and an XL 91 four stroke is only $30 more!

Does anyone have any experience with Magnum engines? I assume they aren't as good quality as OS but if they are reliable enough for easy sport flying I may just buy the Magnum four stroke.

Would you rather have an OS two stroke or a Magnum four stroke?

I understand that an OS or Saito four stroke would be ideal, but I am simply not going to spend $350+ on an engine just because it sounds better than a $180 two stroke OS. The only way I'm going four stroke is if it is around the same price as the OS two stroke.
Old 05-24-2016, 12:46 PM
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JPMacG
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Magnum engines have been discussed a great deal. The general opinion seems to be that they can be good engines, but Magnum's quality control is not as good as OS or Saito. That is, your chance of getting a bad Magnum is greater than your chance of getting a bad OS or Saito. I happened to buy a Magnum that was a dog - it had an air leak that I was never able to track down. But there are many people who are perfectly happy with their Magnums. Search on Magnum on this forum for more information. I don't remember it all too well.

Last edited by JPMacG; 05-24-2016 at 02:31 PM.
Old 05-24-2016, 03:07 PM
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aspeed
 
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I would get a two stroke Magnum, mostly because there is less chance for fit problems and air leaks. KISS keep it simple s___. I generally like two strokes best because of the simplicity. Magnum/ASP have been improving lately, so a new one may not be as much of a gamble as it once was.
Old 05-24-2016, 05:10 PM
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jeffie8696
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If you buy Magnum buy new with a warranty. My first Magnum four stroke was a 52 and it had leaky valves and a tooth broken off the cam gear, after sending it back twice they replaced it with a new engine and that one runs good. Not as refined as an OS or Saito but serviceable. Have you thought about a good used engine? brucercengines.com has loads of proven used engines in stock
Old 05-24-2016, 05:54 PM
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I like my Magnum 4 strokes. My .91 is over 10 years old and has always ran great, My .52 only has a little time on it but no problems. I would say they are only about 90% as powerful as the same OS. Someone opened up the OS and Magnum side by side. Things like the valves were smaller on the Magnum. If you dont care about having the most powerful engine it is just fine. My 91 was in a CG Ultimate until the elevator pushrod broke and has spent the rest in a Pica Jungmeister. The .52 is in a VK Dr1.
Old 05-25-2016, 05:46 AM
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gunnarmm
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Thanks for the advice guys! I will look at brucercengines.com and see what they have. I am not above getting a used engine as long as it comes from a reputable source. I have been following eBay closely too.
Old 05-25-2016, 06:07 AM
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gunnarmm
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One more quick question - what do people think of evolution engines? They have a gasoline powered engine that would fit this plane for $200.
Old 05-25-2016, 06:16 AM
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Evo engines. Maybe better now, but crummy reputation. Like somebody might GIVE you one.
Old 05-25-2016, 07:55 AM
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I have got dozens of OS motors used, and for the most part have been happy. Most were under $20. I don't think I even bought one new. I prefer the other Chinese brands new, as they have been better as they learn how to make them. OS stuff went through a learning curve too, but it was a loong time ago.
Old 05-25-2016, 10:37 AM
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Originally Posted by JPMacG View Post
Magnum engines have been discussed a great deal. The general opinion seems to be that they can be good engines, but Magnum's quality control is not as good as OS or Saito. That is, your chance of getting a bad Magnum is greater than your chance of getting a bad OS or Saito. I happened to buy a Magnum that was a dog - it had an air leak that I was never able to track down. But there are many people who are perfectly happy with their Magnums. Search on Magnum on this forum for more information. I don't remember it all too well.
+1
Old 05-25-2016, 12:02 PM
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Originally Posted by wnewbury View Post
Evo engines. Maybe better now, but crummy reputation. Like somebody might GIVE you one.
I had an Evolution 61 2-stroke in a Hangar 9 Fokker D-VII and it would overheat, melt the remote glow the plug extension wire and quit and inopportune times. I replaced it with and OS 61 2-stroke without any other changes (same mounting and Hangar 9 muffler) and it's run fine without overheating and no problems with the remote glow. If you've got plenty of cooling airflow then the Evo probably would work.

Jaybird
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Old 05-25-2016, 07:09 PM
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jeffie8696
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I believe he was talking about the small gas Evolution engine. Bruce is a great guy and tests every engine, I have helped him on many occasions.
Old 05-26-2016, 04:39 AM
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RCFlyerDan
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Working on your engine at the field vs. Flying your model while at the field. Or! Better yet! Dead Sticks vs Landing under power!

Last edited by RCFlyerDan; 05-26-2016 at 11:57 AM.
Old 05-26-2016, 09:47 AM
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Originally Posted by RCFlyerDan View Post
Working on you engine at the field vs. Flying your model while at the field. Or! Better yet! Dead Sticks vs Landing under power!
That is true. In Germany the letters "O.S." are translated by modelers as an abreviation for "Ohne Sorgen" which means " Without worries".

The good thing on Magnums is that tinkering with them everytime you are at the field makes you become an engine expert in the eyes of the unexperienced or electric fliers. It doesn't matter if you get them running or not.
Old 05-26-2016, 10:24 AM
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Dan you, HIT THE NAIL ON THE HEAD!!!! I always try and steer new pilots away from used engines and too OS engines. I figure if they learn to fly first, They can learn to "fiddle" with engines later. I couldn't have said it better, and I would consider any engine on the bay as "Not working" no matter what the add says. If you get one that works, Consider yourself one of the lucky ones. Thanks Kevin
Old 05-26-2016, 11:28 AM
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warhwk
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Originally Posted by gunnarmm View Post
Thanks for the advice guys! I will look at brucercengines.com and see what they have. I am not above getting a used engine as long as it comes from a reputable source. I have been following eBay closely too.
I buy a lot of used engines on the Bay as well. Most have been good, but I recently got burned. I would never consider this an option for a new flier. A reliable engine will make or break a new pilot.
My experience with Magnum has been good, but I've never experienced a single problem with a new O.S. Ready to go right out of the box. Two tanks on the ground slightly rich then they're ready to fly.
Old 05-27-2016, 08:40 AM
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blw
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Originally Posted by wnewbury View Post
Evo engines. Maybe better now, but crummy reputation. Like somebody might GIVE you one.
Not so for glow engines made in the Sanye plant. I've bought 9 of them and QC, fit, etc is as good or better than OS. The Evo .61 shipped without a carb O ring for a while way back some 10 years ago.

I also got another engine almost for free from someone who claimed he had tried everything. It was grossly out of tune on the low speed needle, and had a very cold plug in it. It had also survived a deadstick crash on a hard surface. Nothing is wrong with the engine. 8^)

Last edited by blw; 05-27-2016 at 08:42 AM.
Old 05-31-2016, 09:18 PM
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jeffie8696
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Brucercengines is a good bet because he tests every used engine. Regarding Evolution engines the one 46 glow that I have is a good runner. And regarding OS although they are generally good my 52 Surpass doesnt run right. And I have tried everything even replacing the carb and will next try a new cam. The rest of my OS engines run good.
Old 06-01-2016, 08:40 AM
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blw
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Every engine that is decent will have winners and losers come off the production line and make it into the box. That's why the top competitors buy 10 engines, test them to find a couple of the best ones, and sell off the rest that didn't make the cut.
Old 06-01-2016, 09:00 AM
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Having been a quality control supervisor I know how it happens and I wont let it change my high regard for OS engines.
Old 06-03-2016, 05:22 AM
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OS has high quality control but uses cheap nickel plating. Magnum has lower quality control but does use real chrome. Prefer other brands with rings myself.
Old 06-03-2016, 02:36 PM
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My favorites are ringed OS and my Irvines

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