Hi guys,
Having a little debate at the moment about the differences between 2c and 4c.. more so for the speed related to each engine, aswell as their aerobatic use. I am stuck on the decision to go 4c or big 2c for my extra.. and am worried that if i go a 2c it will have only top end and create to much speed, whereas the 4c wont have the top end but will have the mid range torque.. in everyone's oppinion is 4c a better option for aerobatics? Taking into account everything... i.e. prop sizes, power, torque.

I know the 2 stroke i am looking at will give me serious verticle authority, but the 4c will be boarderline, but i think the 2c even with a low pitch prop will still create too much speed.. what do you think? I just dont definately dont want a speed demon. I know its all in throttle control but i think you get what i mean bout 2c's.

Ps. The engines are an O.S. 1.08 2c and a Magnum 120 4c for a 8-9lbs model.

I think probably a 4 stroke makes a better all around aerobatic plane because of the low end grunt it has. For pattern style aerobatics or a sport style plane I think a 2 stroke has better all around performance. That being said, I normally by 2 strokes because they work great and I'm a cheap ass.

ha ha i love 2 strokes though.. from bikes to go karts etc. all my shyte is 2 stroke Nothing like raw 2 stroke power band lol but were not talkin cars and bikes now lol so i'm sitting on the fence, not sure which way to fall. I think your right tho, the 4c is better for all round aerobatics, because of the low end power.. i can't see a two stroke regardless of size doing much in the way of low speed aero?

First of all, you will suffer nothing by pulling a 9lb plane with a 120 4-stroke You should have unlimited vertical with that combo

Second, you go through twice as much fuel if you use the 2-stroke.

Third, all-around performance will be better with the 4-stroke.

No doubt about it, go with the 4-stroke.

I like the throttle response of the 4 stroke.....
I'm not a speed demon, but the 4 stoke can still go Plenty fast... but the Pull is GREAT!

I agree with MINNFLYER..you will have plenty of pull with a 120 4 stroke on a 8-9 lb plane and my preference is a 4 stroke,I hate the wing-ding-ding--ding sound of a 2c engine either in a motorcycle,lawn mower or anything else.
I love the deep sound of my Harley.
When is the last time you heard that 2c sound in an real airplane except for an ultralight.[sm=lol.gif]
Also you will have no problem with a Magnum 4 stroke,Magnum is a good engine!

I would think both of these will give similiar power. My OS 108 turns a APC 16x6 at 9k on 5% at sealevel. I believe your prop selection is more important for speed/power and you should be looking for great throttle response in the mid range. Weight is a smaller issue as is size. Its hard to beat the OS 108. A club member had one in a 1/4 Cub swinging an 18x6 inverted. It was great! I do love 4 strokes though.

Carl

Thanks for the replies guys! Extremely helpful.. looks like the Magnum 120 is a good option then!! I am just worried about making the wrong decision thats all.. but i think for what i am after the 4c will be the right option. I was glad to hear that the Magnum is an okay engine, and was more impressed when i saw it in store, it looks alot better than i expected. So you think it will have near unlimited verticle?! Thats what i want!