Hi everyone, Ive just finished my extra 300 65inch model I want to use a four stroke engine I want decent vertical climb out would an os91 do it or ys 110
also would an os120 be to big?

A friends got a similar size cap on a Moki135 which has pullout from hover, so I'd think the 91 would be a bit small

weight seems to be the bigger factor to some guys... whats the weight?

weight is around 8 pound

I had a Vector flgiht Extra about that size with a ST 90 and it flew great but didnt have 3D power. It wasnt a 3D plane anyway. I loved the way it flew and it always pulled through loops and had almost unlimited vertical.

So for climb out of a hover you will most likely need a little more than a 4s 90 although it will fly very well with that engine.

thanks for helping guys, im undecided between the ys 110 and the os120 with pump the ys is 800grams and the os is 1000 grams I want the 120 but the rating on the plane only says up to .90 four stroke, (the ys 110 is rated same as 90) . Do you think the 120 will be too heavy the extra 200 grams?

Go for the YS110 with 25% nitro, it will turn a 16x6 at 10,500 RPM (without muffler). Mine was turning about 9,750 RPM with the muffler and it would haul my F90 with ease. An 8 lbs plane will be a blast.

Some people find that they need gobs of power others do not. If its an 8 lbs plane and you want to just fly aerobatics then a SA100 will suffice, if you wanna 3D the YS110 will be great fun. For a 'cheap' motor the OS91FX will be good to go with, you can run it on 15% nitro. Its a very reliable engine.

Also, 200g is about 7 oz-8 oz. To be honest it all depends on what you want. Some planes are built too light or too heave that it ends up tail heavy. In that case the OS120 will be a better choice. If its well built why not go with a SA100? Keep the wing loading light ... so it all depends on what you want.

If you really want something in the 120 size, you might think about the new Saito 125. You'd get plenty of power and since it only weighs 700 grams you'd be lighter than either the YS 110 or the OS 120 and it bolts into the same mount as the Saito 100.