Guys,

pretty please explain me what is the advantages of one over the other? I am just about to
build my first trainer, so the engine is an issue. As far as I understood, 4-stroke has to
have more volume for the same power, hence heavier weight, so what's good about it?

kukarzev

P.S. I have almost decided on SPADET, so it will probably be a .46 OS or something like that,
but still...

There was a thread on this not too long ago: http://www.rcuniverse.com/forum/m_15...tm.htm#1538278

Well first off not all 4strokers are heavyer than thier 2 stroke counterparts. Saito's are very light for thier size.

A 2 stroke is simple and inexpensive. They are robust and can take a beating usually. They use more fuel than a 4 stroke and have a more annoying sound. For a first plane they are usually best. They are not complicated and have less things to go wrong. They make a lot of horse power.

A 4 stroke has a lot of torque. It will swing a larger prop than a 2stroke. They are more fuel efficient. They also have a more plesant exhaust sound. They are more complicated, and have more parts to break. They are also longet than 2 strokes because of the carburetor in the back. They are harder to prime if you have to. They are also more expensive. Adjustments to the carb can be more difficult also.

My personal opinion is to buy what you want. But my experience would say buy a 2 stroke for your first engine. It will teach you how to run an engine. If you damage or break it. You will be out less money. I hope this helps.

Mark Shuman

Phread59 offers excellent advice. Cheaper 2 stroke 1st up and worry about 4 bangers later.

Yep, I'll agree with all that. Get a 2 stroke for your first engine.

I'll also add that the torque of a four stroke is great, and that there is nothing like the sound of a 4 stroke. I bought my first one a couple years ago, and will probably never buy another two stroke.
Dennis-

I use 2 strokes on many 40 size and smaller planes, but once you hit the 60 size planes, I go 4-stroke all the way. (Except gassers of course)

Thanks for clarification. I think I got a picture.

kukarzev

Price ... power ... propsize mainly the four strokes are a much more reliable engine .If you have an experienced person helping you, I would jump right into the fourstroke, you will never look back.

Now that I'm not smacking the engines into the dirt every 3rd flight I plan to shift to using primarily 4-strokes.... as fast as my budget permits.

You may be one of the "lucky" guys that manages to never smash a plane hard enough to demolish the engine. Or you may be one of hte unlucky guys that can't go 3 flights without bending a crankshaft.

Since we can't predict that... and its a lot cheaper to replace crankshafts in 2-strokes than 4-strokes... I would recommend starting with 2-strokes. If you aren't going to be busting up the engines... then the 4-stroke is a huge improvement.

a .91 4-stroke puts out up to 1.5 times the useable thrust as a .61 2-stroke and if you include the muffler... the more powerful 4-stroke is possibly LIGHTER than the 2-stroke. The stock mufflers on 2-strokes weigh a lot more than the stock mufflers on 4-strokes..