jigeye

I've read where mostly it's Saito 82 or a YS 63.
Question: I would like to go the 2 stroke route. What size for this bird? Are there any real drawbacks to going 2 stroke?

tukkus

My Feedback: (2)

i think the only drawback will be that you wont get as much as the plane has to offer going with the 2 stroke. With the 2 stroke you won't get as much prop wash over the surfaces so it may react differently than a larger prop in slower flight.

the 82 and 63 weigh almost the same and i think a OS 46 AX weighs the same....that might be your best bet

wildnloose

If I had to choose a 2s I would go for the new os 55 ax. It should be similar in performance. They also recommend a 13x6 prop and its $10 cheaper than the os 50 sx.

If you insist on going up to the 61 size then I would choose a 91 sized engine instead (same weight penalty as the 60 size).

jigeye

I wondered about that, however, I see a lot of 3D planes with 2 strokes also so I don't know how much it will affect it.

wildnloose

To be honest, a good pilot can 3d just about any ship made. Its obvious some are easier to fly than others.

If you have the skills it will not matter much which type of engine you have. 2 strokes make the most power in the upper rpm region, 4 strokes make it easier for us lesser skilled pilots (more consistent power band thru its throttle range). That is why you can use bigger props and lower rpm's.

Walt and Sage

O.S. .91 FX Ringed w/Muffler

SAME size and weight as the 60 with
MUCH MORE POWER

You can certainly use the larger props if you require them..

Jimnie

Aw man, this is a 4 stoke airplane if there ever was one. Light weight, lots of wing area, flies great at low speed and can use the mid range torque that the 4 strokes excell at.

When you actually get the model I think you will have second thoughts about putting a 90 2 stroke in it. It is big enough but it is very light. I had thought about the FA-125 because it is light weight but after getting the model I put the FA-82 in it. You can actually get the entire exhaust inside the cowl (using the Saito right angle adapter)so there are no holes for muffler or head sticking through. This thing is 200 square inches smaller and almost 2 pounds lighter than a Funtana 90 which flies great with a 4 stroke 100.

Weight is a primary design feature of this model. You have the opportunity to use mini servos, battery etc so I can't help but think light weight engine as well. And turning the 14" prop works out very nice as well.

If you have to use a two stroke have at it but it just sounds and looks so sweet with a 4 stroke.

Jimnie

asmund

About the fx 91 weighing the same as the fx 61, this is not exactly true even though OS want us to believe so.I have both and my digitale scale shows 770 grams for the 91 with muffler and 700 grams for the 61 with muffler. That is almost 3 oz in differense

Walt and Sage

On the OS home page they are both:
19.4/550 oz WITHOUT mufflers..

the 91 muffler is longer ( the weight difference)
if you are so inclined to use it..

happypappy

My Feedback: (10)

The Super Tiger 90 will definitely do the job also and a heck of a lot less expensive than the OS. Flew my big draggy Ultra Stick 60 with this engine against a friend with a Matt Chapman Cap 580 with the OS 91FX, same tank volume, same props and identical performance. He didn't have much to say! You can buy about two and a half Tigers to one OS.

RVM

I'd go with a 4-stroke just for the transition and lighter weight.