I have looked thru the forums and it looks like Ryan with an OS 120 is a bit underpowered
I plan to fit a ZDZ 40RV gas. Has anybody tried this combo before?
It will turn a 20X8 to a 22X8. It weighs 2.86lbs.

You must be joking...my buddy has the same plane with a YS 120 and it is plenty.

Thanks for the reply but with the ZDZ 40 you can always throttle back

Underpowered with a 1.20? You gotta be kidding!! I fly the GP Civilian version Ryan with an OS 91 FS and its plenty of power!

Underpowered with a 1.20???

hahahahahahahahahahhahahahahahahahahhahahahahhahah ahahahhahahahahhahahahhahahahahahhahahahahahahahha hahahahhahahahhahahah (thud!)

You're joking right?


Jeff (I gotta stop feeding the trolls)

One of the most important things to consider when choosing an engine is WEIGHT of the engine. Sure you can throttle back but you might ruin the plane's performance if you need to add lots of balance lead to the tail...always think twice before changing the power choice of the people who designed and tested the airplane before you started messing with it.

Yak

I have a civilian GP Ryan STA myself. It's powered with an OS 120III w/pump and a 16x8 prop. I have additional weight in the form of the Robart struts and an MGA pilot (I don't have a good weight scale yet, but two cheap ones each put me at just under 12lbs). Regardless, it is definitely not underpowered.

However, it is also not overpowered either. I can't fly that thing around like a lightweight aerobat, but I do get off the ground quickly and get very good scale response (actually, I'm sure it's much greater than scale). I have to nurse it through some manuvers, paying attention to my airspeed, but I'm enjoying that tremedously in a scale-like way. If you want to fly specifically on the prop, then it may not be enough motor. But then, that might not be the right plane for that either. I cannot just point it anywhere in the sky, at any time, and have it go forever in that direction, but I've decided I don't want to do that with this plane.

I guess your engine choice depends on how you want to fly it. I have to admit that the cool checker pattern sort of begs me for more engine, but I'm satisfied with what I have. BTW, if I'm not mistaken, a YS 120 has at least one more horsepower than an OS. I'm not sure they're a good comparison against each other.

I've debated for a little while now about putting more engine on it, but I've decided to keep this nice flyer as is. It's an awesome platform for imagining I'm flying something full scale and for practicing fully coordinated manuvers. I'm kind of new at all this, but later on I'll get a proper aerobat for completely unlimited flight.

Hope this helps.

I've been flying my dads with a OS 120 Surpass pumped motor and it's more then enough!! This is not a 3d machine. If ya put that big a motor in it the wing loading will suck.. its a great lazy day flying model.
happy flying
frank

thanks too you all for your help and info.
happy fling too all

I have the SIG kit version of this plane. It is a bit smaller with a 72 inch wing but it is about the same weight as the ARF. I fly mine with an OS 91 FS Surpass II and she flies very scale like. I have seen a lot of posting about putting BIG engines in these models to try to get them to do 3D maneuvers. These plane were not made to do that stuff. Get a 3D capable airplane if you want to do 3D stuff. Don't screw up a perfectly good scale plane...

saito 180 weighs 880 grams with muffler compared to 920 grams for the os pumped 120.

Don't forget cost,,,
We are not all rich you know..

Vic,

I'm with you. I had the SIG Ryan and now the GP one. I can honestly say the GP Ryan flies much better and is wayyyyyyyyyyyyyyyyyyyyy more simple to build. It took me 5 years to complete the SIG kit. Talk about a box of wood that you carve into the shape of a Ryan...sheesh :stupid:


baringer,

The Ryan can use the extra weight of the OS120 in the nose. And while the Saito 180 is a powerhouse it's still too much for this plane. Besides you'll never need all that excess HP the 180 has. Why waste it's use in a plane like the Ryan when it can be better utilized in a H9 Cap 232. (the smaller 80" version)

baringer & Paul Terry,

I got lucky with my OS 120 pumped. Tower had a sale on OS engines plus a $25 discount for orders over $200. I ended up getting my 1.20 for $300 shipped. That was less than the price of a non-pumped 1.20 which wasn't on sale

Jeff- who's loving his Ryan ST-M on an OS 1.20 pumper and will never be persuaded to change it for anything

I have to agree with jbrundt about the ryan needing the weight in the nose. Before my robostruts I had about 3 ozs of weight on the firewall. Now with the struts, and wanting the C/G just inside the rear limit, I have only 1 oz on the tail. I think the OS 120 was made for this plane, or vice versa.

Only three ounces?
I wouldn't even put it on.
It's not very likely that your going to run out of fuel so
why putt it on?
These planes are made to fly unless the balance is way off.
I would put it on if it needed four but three is not that much difference.

Well...at the risk of changing the topic...did I mention I'm new? This is my third plane after starting last year. Being the engineering type I've more or less followed a lot of what I've read to the letter...that is until I learn what I can get away with.

I started out not wanting to change a thing anywhere. But already I've modified my trainer heavily (dihedral gone, changed to tail-dragger, added 7/8" to width of rudder, and some other things). So I'm learning. I've noticed on RealFlight that moving the C/G a couple of inches can be disasterous. But that's a sim and a couple of ounces probably won't come close to changing the characteristics that much.

I'm still playing around with things like C/G, control throws, etc. Interesting point...I'll mull it around and keep it in mind.

If I were you I would go with the Great Planes Space Walker!
and put a O.S. 91SII Four stroke.