OS .50 SX versus YS .63

I agree with Frank on his entire post.......especially since the YS is quite a finicky engine, but I would strongly suggest you also consider an Irvine .53 in the list of choices.......awesome power, mine turns an APC 12.25x3.75 prop at 13,500rpm! This is with the Tower Hobbies .46 muffler, never tried the stock muffler yet but the tower muffler weighs less. I would bet the Irvine (with this muffler) weighs less than the OS 50, but not sure.

Brad L.

The Webra .50 is also a popular choice, though I think it's better suited for high-speed applications, it loves to rev I hear. From experience and second hand accounts, the O.S. and the Irvine are probably your best bets for power and reliability in that range, I hear nothing but good things about them. If you're set on 4-stroke, you may want to consider the Saito .72, not quite as powerful as the YS, but simpler in operation. I've heard great things about it.I'm not putting the YS down, but from what I've gone through with this engine, I wish I'd waited until I had more 4-stroke experience, that's all.

I have a YS 63 and i love,love love it..........

If you can afford the YS buy it. You won't be disappointed. I promise. Eddie Fulmer

There is no primer for a YS four-stroke, Frank. Owning any other four-stroke glow engine would not have provided you with any useful information. The YS is in a league of its own.

I prefer two-strokes for that particular size range. They get along just fine burning 5% nitro fuel and have no pesky diaphragms and other junk to malfunction.

Ed, NM2K

I have the OS 50 heli version and had the rear bearing wear out in less than

20 flights. I replaced the bearing with a ceramic one and removed the webing on the crankshaft that covers the bearing so it could get more lube to the rear bearing. Motor seems to run a little smoother now so it must have also helped the balance too.

a .45 size p-51 model

a .45 size p-51 model>>>>

The P 51 definately needs a 4 stroke......

IMHO, there is only one engine in this size range and thats the O.S. .70 Surpass II. It's not the lightest, but it's not bad. It's not the most powerful, but it's right up there near the top of sport engines in this range. It IS however, the most user friendly engine I've ever had the pleasure to own....and for that reason I've had three of them and I wouldn't hesitate getting another if I had the need.

All you do is open the box. install the engine fuel it up (sometimes make a minor adjustment to the idle) and go fly. I have a .70 Surpass II that will easily hover my 6 lb Venus and punch out of the hover. I use 10% Cool Power and O.S. type F plug and an APC 13x6 prop. I get 11,000 peak out of this and I back off the needle to about 10,800. It's a awsome combination of power and dependability at a reasonable price.

Say, did I mention that I like my O.S. .70?

Cheers,

Wiz

Might I suggest you look at a Webra .50? One of the best engines ever in its class.

The Webra or the OS is more suitable for light, agile models than a punishing 4 stroke. Look hard at a Webra .52 AAR Heli. Killer power, light, and very user-friendly.

Bob