Witch is the prefered engine, I have a 53" GP Eagle 580 and
I want to put a very good eng in this plane.

Not worried about price, just whats the best and why.

Jimmy

A total toss up.

Tom

My preference would be the OS hands down

As far as quality they are probably equal.
Saito fans will tell you it is best. OS fans will tell you the opposite.
I'm an OS fan, probably because OS is the overwhelming favorite at our club. A few 'new' members have introduced us to Saito but they are still fairly uncommon.
Saito still expels excess oil into the air through a crankcase vent. OS routes that oil into the cylinder so it relubes a little and is blown out the exhaust.

A 6-7 lb Cap with a .81 4 stroke?? I wouldn't do it. I would go with a .91 4 stoke. Thats just me though. A 81-82 4 stroke would fly it just fine, just without a lot of authority. Saito's are a little lighter, but both engines are great. The longer stoke Saito .91 for $10 more than the .82 would be my choice.

If you do go with a bigger engine, move the battery pack toward to tail to balance. DO NOT ADD WEIGHT to balance.

And I think you should fly something else between the trainer and the Cap. Doesnt matter how good you get with the trainer, the Cap is a big step. If you are confertable with your trainer, your 2nd plane should be a good low wing "sport trainer" type. Take a look at the Pulse 60 from Hanger 9. Great 2nd plane.

When you do fly your Cap (eagle 580) keep your air speed up and land a little faster. DONT try and "float" it in like your trainer.

One more thing, put two fat black stripes on the bottom of each wing. Makes it MUCH easier to keep your orientation.

Ihave both but I like the Saito just a little better.

Saito!

Yes the O.S.'s are good engines, but you wouldn't believe how tolerant the Saito is of mis-tuning!

I've seen people complain that the Saito's consume more fuel, when they haven't realized that the engines they based this on, were completely mistuned, often with the needles as much as 11 turns out from optimal!... yet the plane still flew just fine!

The Saitos also tend to be much ligher than the O.S. engines.

G'day I have both and I prefer the Saito. Not that the OS does not run well but the Saito is lighter and less complex. Where I am, the Saito is also quite a bit cheaper too.

I own or have owned both the Saito .82 and the OS .81-FSa.

The OS is the better of the two engines in my opinion. That's not saying that the Saito is a bad engine, because it isn't. The OS is just a newer design that works a little better. It seems to make more power although that is just anecdotal evidence based on pulling the same prop on the same fuel; I haven't actually measured it. The nicest thing though is that the OS .81 spits very little oil out due to the lubrication system design. It is even cleaner than the older OS engines.

When most people compare OS and Saito 4-strokes they are thinking about the older OS's, not the newer FSa line. The FSa's are outstanding. I own both the 1.10 and the .81.

You really can't go horribly wrong either way of course. It comes down to preference and what you are willing to spend. I'd go for the OS though; that's just me.

Also, I flew that Cap on a YS-.63. It was PLENTY of power. Either of the 4-strokes you are looking at will do just fine for the airframe.

I have both and love them both. If you really want the best power to weight then go Saito. I find the OS's run well right out of the box. My saito's have needed a gallon or so to reach the point where they are tune and forget, the OS tends to be there right out of the box.

I cant speak for the OS .81 as I have nver owned one. I have owned many OS products over the years and have always enjoyed using heir engines. Although I have used the Saito .82 ALOT. It has been a great motor and very easy to live with. I will agree that the oil residue does get old. it was very hard on the covering of my Reactor. To be honest I think you would be good to go either wy.

Both are OK but I like the OS better, I also find the OS has more power, about a nickles worth!! My main problem with the Saitos is they run so fat they sling oil all over the place, just really nasty. I find the OS much cleaner running right out of the box and hold there tune better. If someone is giving me a used Saito or OS I never say no to either one. It may help too if the guys at your field are using one or the other more. In my area the hobby shops sell Saito so I see a lot more of them, if you need help with your engine it's nice to have one that most the guys know how to tune, I'm the only YS user where I fly, trust me, I'm the only one there that knows how to tune one! It's a mystery engine to most people and a lot of myths surround them.

They are both very good. Though I have not used Saitos myself, their reputation is second to none. You will find that the Saito is lighter than the OS and may be a bit cheaper than the OS81.

May be you need to select based on which of the two is better known at your field

Ameyam

My Saito's don't spit out more oil than my O.S. engines.

That could be due to an overly rich condition, which the Saito's tolerate just fine.

They get better as they break in but compared to the OS they are snot slingers. If I'm buying new it is OS, on trades or engines given in payment for work done I will take them both. I just find the OS a bit better but like I said, it's about a nickles worth. I like the Saito 100s but tend to reach for the OS .91 when I'm building. Just a choice thing. I like both makes and I would reach for the Saito 1.25 before the OS 1.20, I just don't have any of the Saito 1.25s under the bench at the moment.

"Snot Slingers" - ROTFL!

I'm not having any problems with that.

I'm running 5% Cool Power on mine and IMHO I have them tuned up pretty well.

I have a Saito 1.00 on an old Funtana S90.

I see a lot of complaints about this combo not producing a lot of power, ( a lot of people went with the 1.25 instead ) but with a "W" prop mine pulls stumps!

I wonder if it's because I'm flying at a lowly 230' altitude?

There's no excess snot to speak of, but I do have the exhaust angled down and away from the plane.

The old Ford vs Chevy debate. As long as there are two people around to argue about it, it ain't gonna get settled any time soon. Because there is no "right" answer.

Personally I think there equal in quality of mechanical performance, Saito has OS crushed in the price per HP category and usually power to weight category thats why I use them.
Id put a Saito 100 on it, power to weight its an awsome motor. Maybe a little excessive but I have yet to hear " I don't like this plane it has too much power"