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 Post subject: My oopinion of OS Four Strokes verses Saito Four Strokes
PostPosted: Fri Oct 14, 2011 5:02 pm 
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Location: Indianapolis, IN
After rebuilding one of each brand of four stroke engines (OS FS91 SII-P and Saito 150) I have an opinion of the methods of construction of the two engines.

Send me an E-Mail for my frank opinion!
Clancy

clancyarnold@juno.com

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 Post subject: Re: My oopinion of OS Four Strokes verses Saito Four Strokes
PostPosted: Fri Oct 14, 2011 9:43 pm 
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Location: St. Paul MN
Oooooo, a mystery...

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 Post subject: Re: My oopinion of OS Four Strokes verses Saito Four Strokes
PostPosted: Sun Oct 16, 2011 12:51 pm 
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Clancy----I bet you like the Saito better. :D

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 Post subject: Re: My oopinion of OS Four Strokes verses Saito Four Strokes
PostPosted: Sun Oct 16, 2011 2:40 pm 
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Frank
You loose.
Clancy

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 Post subject: Re: My oopinion of OS Four Strokes verses Saito Four Strokes
PostPosted: Sun Oct 16, 2011 5:38 pm 
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It's that two part crankshaft on the Saito I'll bet! :D

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 Post subject: Re: My oopinion of OS Four Strokes verses Saito Four Strokes
PostPosted: Sun Oct 16, 2011 6:31 pm 
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Actually Frank it is a three part crank and and a four part cam.
Or a five part cam if you count the solder.
Clancy

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 Post subject: Re: My oopinion of OS Four Strokes verses Saito Four Strokes
PostPosted: Mon Oct 17, 2011 11:36 am 
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can you put up pictures? I bet that engine got abuse or crashed..............

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 Post subject: Re: My opinion of OS Four Strokes verses Saito Four Strokes
PostPosted: Mon Oct 17, 2011 9:46 pm 
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Frank
I no longer have the Saito engine, I returned to it's owner after I assembled it for him. My comments are based on how the engines were designed and built at the factory.
Clancy

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 Post subject: Re: My oopinion of OS Four Strokes verses Saito Four Strokes
PostPosted: Wed Feb 01, 2012 8:46 pm 
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Location: Harsens Island, MI
Clancy

Yea, there are trends but there are also different models from each , some good, some not so good. The OS .30 is in incredibly sweet and smooth running engine.... with the power of a weak .15. I have used it on a number of planes. Weighs a ton and no guts, but smooth as a turbine. I've used both the Saito .91 and .72 extensively. The .91 is a decent motor, not as much power as they advertise. Nothing special I'd say. The .72 I like. It runs rough as a cobb but has great power and torque. You need a strong fuse for it. All of these motors start nicely but I will not start any four stroke without and electric starter.

Just as an aside, I have a good amount of time on Magnum .91 and .52 four strokes. The .52 runs as smooth and sweet as you could want, but not a lot of power. Ok sport motor. About the power of a .40 but with the bigger prop it turns it will fly about what a .46 will fly as long as speed is not your thing. It will not hover a .46 size plane though. The .91 I do not have a lot of use for. Very tempramental. I gave mine away and the guy who loves the things and has much experience with them gave it back to me! Maybe it was just not a good motor.

The OS 1.20 is my favorite four stroke. Smooth, really strong power. Turns a really big prop and just keeps on pulling. Fabulous for either precision or 3D aerobatics, but you sure would not want to be involved in anything with wires on it with one on the nose unless you have really thick wires and a really big field, cause it would drag you across it.

OS however also gets the worst motor of any type I have ever seen award...The OS 2.00 four stroke. This is a truely defective design. Trying to break them in they only broke. The cam gear was not designed with sufficiently tempered alloy and the strip before the 4th run. OS sent me replacements.... I sent them back totally useless. Finally had them send me an OS 1.60 two stroke instead which is a super motor with nearly as much power.

just my experiences of course, and your mileage may vary. But today in both control line and rc I only have 3 glow planes left and they sport the OS 1.20, 1.60 and Saito .72. I hate to give up the planes just cause the motors are so good. But they are all 3D planes and when I kill them that will be then end of them and I will be eternally electric.... unless they make it impossible to get lipos... but with all the lipo manufacturers moving to Michigan, I do not expect that.

bob branch.


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 Post subject: Re: My oopinion of OS Four Strokes verses Saito Four Strokes
PostPosted: Thu Feb 02, 2012 11:01 am 
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Bob
I have never explained the reason for my dislike of the Saito engine.

I have two OS FS91 engines, the first is a FS91 SII-P that powered my Taube. I bought it used and it ran great until the NATS when it was way down on power. The problem turned out to be a loose crank case vent nipple allowing a loss of lower crank case pressure that reduced the amount of fuel the pump could supply to the engine. It acted like a governor on the engine. A friend gave me a NIB FS91 S engine to replace it with. The new OS FS91 Surpass is now in the Taube.

The Saito engine needed a new camshaft installed. The OS engine camshaft is made like the cam in your car, a one piece shaft with the lobes ground to shape. The Saito camshaft is an assembly that has the lobes and gear soldered to the basic holllow shaft, which appeared to be brass, and one of the lobes had broken loose!

The OS engine has a section of the crank shaft machined to serve as a gear to drive the camshaft. In the Saito engine there is a piece slid over the crank shaft and pinned in place to drive the camshaft. The Camshaft in the OS engine is supported on two ball bearings, The Saito camshaft assembly is mounted on a 1/8 Inch Diameter rod and spacers are used to position the cam in the housing.
Clancy

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 Post subject: Re: My oopinion of OS Four Strokes verses Saito Four Strokes
PostPosted: Sun Feb 05, 2012 12:10 am 
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You can say what you want about the Saitos.... but they shake so well!!!!!!!!!!
.....oh.... those might be some of the reasons for it! :roll:

bob
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 Post subject: Re: My oopinion of OS Four Strokes verses Saito Four Strokes
PostPosted: Sun Feb 05, 2012 9:02 am 
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I've been thinking about getting that Corsair kit from Brodak and putting a four stroke engine in it with a U-Tronics throttle control. John Brodak says a B-40 will haul the model good so I wonder what 4-stroke to put in it.

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 Post subject: Re: My oopinion of OS Four Strokes verses Saito Four Strokes
PostPosted: Sun Feb 05, 2012 9:54 am 
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C-Lcarlisle wrote:
I've been thinking about getting that Corsair kit from Brodak and putting a four stroke engine in it with a U-Tronics throttle control. John Brodak says a B-40 will haul the model good so I wonder what 4-stroke to put in it.




Frank, And to think a few posts back you were going to retire from modelling when you supply of models wore out. I knew you couldn't leave all this fun.

Dennis


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 Post subject: Re: My oopinion of OS Four Strokes verses Saito Four Strokes
PostPosted: Sun Feb 05, 2012 12:46 pm 
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Dennis----it's sunny outside-the crocuses are in bloom.......................................................

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 Post subject: Re: My oopinion of OS Four Strokes verses Saito Four Strokes
PostPosted: Mon Feb 06, 2012 1:37 am 
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...and Frank is reborn!!!!!

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