I am looking to buy a 4stroke engine 70 size for my first kit,a Tower Uproar.
Between OS FS 70 Surpass and YS 63FZ-S,which one do you prefer?
YS has lower weight than the OS,but OS requires only 5% nitro to be happy,in addition to the YS that needs 20++.
So,please help me to decide.
Also i haven't any real experience with 4stroke engines,so i am looking for a guaranteed reliable and easy to tune engine.
Kostas.

P.S. YS costs 30$ more[>:]

You forgot to mention the best one, the Saito .72 or .82.

Hello Kosta 1; I would go for a Saito too, but I remember that you had a bad experience with the Saito distributor where you are, so I guess I would have to recommend the OS 70 over the YS. Either engine would be fine, but I hate the way the new YS' look, with pipes and hoses everywhere. I have gone through a few OS 70's in my time and I think that they are the best of the surpass series, even though they are quite a bit heavier then Saito, and not as strong (my opinion only), and not as pretty. The 70's I have had served me well, lots of power and trouble free if you run them a bit rich.

The YS' I see here are always at full throttle, the guys that have them run them flat out from start to finish. I don't know if they don't throttle well or if they are hard to tune properly, since I have never tried to tune one. I'm just commenting on what I have seen.

I would do an OS or Saito. Can't go wrong with either one.

I do not own a YS but I do own an OS 70 Surpass. It is totally reliable and easy to run. I followed the OS instructions for break in and use a 13x6 prop. There are pilots in my club who run YS and they do not have problems with them either, but they do run YS 20/20 fuel or 30% helicopter fuel.

Saito engines could be another good option if they are available to you at a reasonable price. The Saito manual does recommend 10 to 15% nitro so I do not know if they would run well for you.

The OS is most similar to the only engines I have owned which are Saito. Less complex than a YS and they have been so dependable and usually easy to tune. If you don't have to squeeze the most power out of every cubic inch, I recommend the OS.

No donkey doctor i never experienced any problem with the Saito distributor,because i had never owned any 4stroke,except of an OLD LEMON YS 53 FZ.
I bought it in an auction,in very good outside condition.
It never worked good except from idling.
Idling was good.
A bit quick but reliable.
So,i couldn't tune it and i sell it to a YS guy in another club.
He said that he could tune it with his left hand[:-][:-][:-][:-]!
HE COULDN"T ALSO.
SO,i don't know what he did after that!
Also,
back to the topic,
i am looking for a 4stroke to install in my future kit Tower Uproar 40.
Tower suggests a 52 4stroke but i thought that it is better to go with a 70 size,because i can have more power and also i could use it in other planes in the future.
I must say that nitro,is expensive here in Greece.
For example the 1gallon CoolPower 15% nitro costs 35-40Euros.
So i am buying 5ltr of 5% nitro on 25Euros.
Cost of nitro is something imprortant.
Saitos do require more than 5% nitro?
And also are easy to tune as OS?

OS - Saito, take your pick.
I have a feeling that here in Europe, OS is more common and in USA Saitos are more common/prefered.

I have 3 OS's that could have been Saito's. I just choose OS when I bought my first fourstroke and stayed with them.
They're well made and easy to set up.

/Test005/

Kostas since you are an os man you should consider the magnums. they are clones of os and I bet they are just as good. magnum offer 70, 80 and 91 but since they are basically the same weight and physical size you should go for the 91. great cheap engine, I do own and run one and could not be happier. the 91 will give you more planes to choose for it later on than the 70. It does weigh just 640 grams muffler included, runs great on 5% too

You're talking about a ton of weight to hang on the nose of that little plane. I would go with a Saito .56. If you insist on a .70 size, go with the Saito as well due to less weight. Those planes are nose heavey even with a .40.

BTW I have several YS engines - They all run great on 15% Cool Power

it the need is a really light weight, still powerful 4 banger, there really is only two choices to consider: ys fz 63-s or saito 82

Saito 56 or OS 52 FS would have enough power to hover the tower Uproar 40?And ofcourse pull out easily?
I also thought the Saito 65AAC,but in less price i can buy an OS 70 Surpass.
Also as i said nitro is expensive in Greece.
And i use 5% nitro,which won't be enough for a YS engine.
Could be?[]

To be able to pull out of a hover with a 50 sized fourstroke that Uproar 40 will have to be really light. what will all-up weight be? I fly a razzle 3-d with a sc 91 fs and 14-4w and that is not to much power out of a hover(6.5 pounds)

I run the OS.52fs on a LT40 trainer and it's a great engine.
Ultra reliable and nice running, but not too powerful. It does an excellent job on the trainer and is good for basic manouvers, but I do not belive it's a good 3D/Hover engine for a 40 sized 3D plane. For general sportflying, sure. For 3D, maybe not.

I have also two Sig Somethin' Extra's now.
One have OS70fs and the other one has OS52fs. I have only flown the one with the .70 so far and it's crazy much power IMO
SSE + OS70fs goes vertical and you can really feel that there's power to spare (I'm no 3D flyer though so I haven't tried any hovering or such.)

If you're interested in 3D type flying and have a choice between the .52 & .70, then go for the .70.
Also, for some reason, the OS70 is cheaper than the OS52 here in Europe... Check it out!

What about the Saito 65AAC?
Will it run on 5% nitro?
And also will it have a bit more power than a 52FS surpass?

The 65 is a fine engine, but is way too heavy for what you want. It is in the same size block as the .80 & .91.

magnum offer a 61 fourstroke at the same weight as a regular 46 twostroke

Thank you all for replying to my question.
I will start saving money for my engine.
I am going to get an OS 52 for starting and then if power is not good for hovering i will switch to an OS 70 Surpass.
Once again thank you all.
Kostas

Kostas1: The OS.70 is cheaper than the OS.52 in Europe.

I am not buying from Europe any more.
All people are trying to make this hobby more affordable,so.
I have a very good friend of mine that lives in FL and sends me everything i want!

Allright, if you're not buying in Europe, the .52 will be a good choice.
My .52 run great, it's a sweet engine...and I think it's perfect for you to get as your first fourstroke. Very userfriendly and is flyable after two fuel tanks of break in.



Today I broke in a Magnum .52fs I bought, it runs great as well and is cheaper than the OS .52.
The OS is 'nicer', better finish and easier to break in, but this Magnum feels good, I have hopes for this one

Em,
i think the difference in price between these two engine is not too much.
So,i think it's better to buy the OS because it has better machining.
That's my thought.
I didn't own any of them in the past,so i cannot tell you exactly.
So,as conclusion to all replies,
is the power of the OS 52FS enough for 3d flying (hovering etc)?
Also will it have unlimited vertical or just good?
And also you mentioned that after 2 tanks of fuel i can fly my OS 52FS?
Really?
How about valves?
I don't know anything about tuning valves etc.
Will i have to tune anything before getting used to it?[]

OS .52 is a good choice. Just read the instruction manual when you get it, it will explain what you need to know. If not, we'll help you out. Enjoy your 4-stroke, you will like it.

Can i ask you all sth else?
Will the OS 70FS bring the wing loading up?
Also is this engine better than the 52 for the additional weight?