Born to Fly

After some research, these are my choices:

OS 50SX (Ringed and Dual Ball Bearings)
ST G-51 Ringed
Magnum XLS-52

Hope to narrow down to one soon. Would anyone help to comment ?

Spaceclam

i have the .50 ringed. i love it. it broke in quickly, easy to tune, very reliable, fairly lightweight, great engine. it will cost you though. i've heard pretty mixed reviews about magnums. some people swear by them. some people couldn't get paid enough to touch one. as for the other one on your list, i have no experiance. however, you also may want to consider thunder tiger (tt for short). they are a lot like the os engines.

AMB

Of the 3 ST51 its less than the OS (only reason same quality) both a notch above
the magnum which is a very good engine have mag 4 strks they are fine. Check
out the irvine 53 I have 3 of them and they are better than OS great carbs

ajcoholic

My Feedback: (10)

The two 50 class engines I would take a good look at are the Irvine .53 (been flying one for over a year now) and the Webra 50. The Irvine is one sweet engine, but the Webra is a bit hotter and as light or lighter.

The Sport Jett .46 or .50 will also kick *** if you want to spend a few extra dollars. My 46 Jett (side exhaust sport version) is awesome. But I would probably get the Webra 50 if I needed a 50 size right now.

AJC

IronCross

Check out the Irvine, way more power then the ones mentioned,
runs so sweet and is pretty too boot

Spaceclam

but irvines don't benifit from extra nitro much when you want a little extra power. they are designed in england where nitromethane is not easy to get. they will tick happily away on no nitro at all so more nitro doesn't really help any.

Bidule

My Feedback: (1)

Hi guys...

IronCross : The OS 50Sx claims to have 1.8HP and the irvive .53 claims to have 1.7HP.
Why are u saying that "irvine has way more power ..." ???

I have an OS 50SX brand new here and i am just waiting next summer to try it. I havent started it yet.
I haven't found any specs for the webra 50 on horizon Hobby.

Maybe the irvine feels you got more power in air ? Did you tried both engines ?

Thanks for infos.

DarZeelon

Martin,

Take ALL the manufacturers claimed HP figures and throw them out the door.

The ONLY usable measure of an engine's performance, is the RPM it is capable of, on different prop sizes (and makes).
It is the only way to compare candidate engines, for performance.

If you intend to use an 11x7 APC, compare the RPM the engines can achieve on this size prop.

You must also compare their RPM on a prop one inch smaller in diameter, or two inches smaller in pitch; a 10x7, or an 11x5, to know how they will perform in high speed flight.

You can take Andrew's words here at face value.

Another candidate, similar to the Webra in price and cheaper and most likely stronger than the OS.50SX is the MVVS .49, with the tuned silencer.

You can find RPM figures in some web sites and in various R/C magazine's engine reviews.

On small props, the Jett .50, the Rossi.53 and the YS .45 are close to the top of the class.
On medium/large props, you would have MVVS and Irvine, which can also thrive on cheap fuels.

pikebishop

irvine 53 is my choice.

IronCross

As Dar said above, forget about the published HP ratings. They mean very little.
I can tell you from pylon racing the Irvine will run circles around the OS 50. We
have (Club level) an open class limited to 60 size and below engines that the Irvines
are currently dominating. On the down side the Irvine prices are getting a little out
of hand. I see Quantum riased the price on there .53 to 146 dollars now. Haven't
checked with Paul at Just Engines lately. I heard Hobby Lobby still sells them for
around 125 dollars though.. Hard to believe a couple years ago we were getting them
for around 80 dollars from JE in England.

DualdudE

Irvine .53 Easy to break in, easy to tune, powerful, relatively cheap

JoeAirPort

My Feedback: (41)

Irvine .53.

Has been a piece of cake right out of the box. Just put it in and fly (ok, ok..I broke it in for 5 minutes on the ground..but that's all).

Joe

IronCross

Right on Joe. I usually run a tank through it and tweak
the low end a little. Then do the rest in the air. The amazing
thing is there are probably 50+ of the .53's in the club and everyone
has come out of the box and fired up the same. Talk about some
quality control. You read these threads about guys having to break
engines in on the bench running god knows how many gallons of fuel
through the darn things before they put them in there planes and you
really have to chuckle. If they only knew..

Spaceclam

a lot of two strokes will have heat problems on benches. no matter how rich you run them, they generate so much heat with no in-flight cooling. four strokes on the other hand will run just fine on benches because they don't generate nearly as much heat. if you have a two stroke, you should only put a tank or two through it if you aren't comfortable with flying it burbling rich right out of the box. that's where i appreciate ys engines. when you buy a brand new car, you don't have to break them in. their quality control on the moving parts is high enough that it will do what little needs to be done very quickly without generating a lot of heat or needing special care. ys is the same way. mine ran just as well out of the box as it does now. it idled perfectly inverted right out of the box, regulator was fine, all that had to be adjusted (obviously) was the high end. currently, it happily swings my master airscrew 15x8 at 9500 rpm on 20% nitro. these engines will opperate at their best at 30%. the guy who owns extreme flight rc (the company i am going to buy my new plane from) has a ys 110 (the one i have) that he can spin an apc 17x6 at 9500 rpm on 30% nitro with. that's about 23 lbs of thrust. i am willing to bet that no other four stroke within the 100-120 size could even come close to that. that gives it the best power to weight ratios of any comprably powered four stroke of any size, and doesn't guzzle fuel. on a four stroke, you only get a fire 1 out of every 4 strokes of the piston. that means that 25% of your stroke is power. on a conventional four stroke, that remaining 75% goes to waste. ys has made use of 60% of that wasted 75% and turned it into power. basically, what i am saying is if you feel you want to go four stroke, go ys. i will never go any other brand. ys is pricey yes, but it is well worth every extra penny. just to back up that last sentence, i am 13 so getting that money is really a pain in the ying-yang. but that engine justifies all my efforts.

IronCross

???????

DarZeelon

Andrew,

If your test stand is not up against a wall; i.e. It is like the CB test stand mounted horizontally on a flat board, with open air-flow all around, you will have no heating problem.

In fact, some engine manufacturers; particularly serious ones, like MVVS and Jett, say that you MUST do the break-in on a test stand and warn you not to do it in flight, or on the plane in general.

I broke-in too many two-stroke engines to mention and I never encountered any overheating problem, ever.
Break-in was always performed on an open air test stand, or on a board with a rectangular notch for engine mounting.

Doing it on an enclosed stand, or on one with a backboard is like running it cowled in.

IronCross

And then some of the Quality manufactures that can hold
tolerances in production like Irvine and Saito etc say it
doesn't matter where you break them in. Face it, it is a matter
of persanal preferance.

Spaceclam

may be so. maybe i am stingy on the needle, i don't know. all i know is my .46 and 50 got awful hot sitting there. who knows. it may get htat hot up in the air and is just cooled down by the time i touch it for some unknmown reason. it just seemed awful hot for the needle settings i was running it at. that's all.

IronCross

Lots of theorys on this I guess. The oldtimers I learned from claimed
they run cool in the air and break in under actual operating conditions.
Kind of been the path I have taken and it has worked great for me. Also
setting one up on the bench just means you have to set it up again in the
plane. Kind of redundent to my way of thinking.

EdMan

WEBRA 50. Lighter the an OS. Very strong. Once you get the needles set, you rarely have to adjust them. Less $$$ than the OS 50SX. I have a couple of the Webra'a and love them. The throttle response instant, and power is awesome!! You will not be disappointed.

EdMan

Bidule

My Feedback: (1)

Hi again....

I am little disapointed because i spent a lot of times comparing technical specs before buying my OS 50SX. I was looking for the most powerfull engine, so i checked claimed HP as advertised by manufacturers. The price was not a factor in my choice. Anyway like i said i haven't tried my SX yet, but next time maybe i should ask for advice in here. The SX is a new engine i think, i hope i won't be disapointed.

EdMan

I'm not knocking the OS 50SX. As I have never owned the 50, just the 46FX. I'm sure the OS 50 is a good motor. I'm just speaking of my experience with the Webra's, and the power to weight ratio is superb at a lesser cost.

EdMan

JoeAirPort

My Feedback: (41)

From what I've heard about the 50SX you will NOT be dissappointed. For most people price is the issue and that's the only thing I didn't like about the 50SX or I would have bought it too. I'm sure that engine will be awesome. Just make sure you break it in correctly (use break in procedure for ringed 2 stroke, not ABN 2-stroke).

Joe

Spaceclam

you will not be dissappointed with your 50 sx. i've got one and an very happy with it. if price is not a factor go with that engine. the only reason it costs so much is because it carrys the os name

Volfy

My Feedback: (23)

Irvine .53, without a doubt. Impeccable carb manner. Transitions silky smooth. And just when you think it wouldn't idle any lower, it drops lower and holds steady as a windmill. Stump puller of an engine, and will swing a 12x6 with ease.

For both beauty and might, the Irvine .53 wins the gold.

BTW, that stuff about engine overheating on the bench: HOGWASH! If your 13yrs old, you have much to learn.

If an engine overheats on the bench, it is nowhere near broken in enough for flight. The #1 worst way to break-in an engine is installed on an airplane sitting on the ground. The #2 worst way to break-in an engine is installed on an airplane flying BEFORE the motor is ready for flight. Deadsticking on a brand new engine on a brand new airplane is not a scenario you want to face on your maiden flight.

The golden rules I've learned over the years is:

1. If the engine can hold WOT for 30sec. with sagging or overheating,
2. If the engine can hold a reasonably low idle,

Then it's ready to break in the rest of the way in the air, still running on the rich side, of course. Otherwise, it belongs back on the bench.

Now some engines will run as described above right out of the box. For example, many OS engines are like that, which accounts for their legendary reputation and popularity. This is not to say they are superior engines just because. Many other fine engines prefer long break-in run on the bench, and then they last forever after that. Super Tigre falls into that category. Tally your priorities and preferences, and choose accordingly.