ORIGINAL: matador_24
Ok, I think I got it, I read the article which explains clearly how it works..... so, what I understand is that the 2 strokes should be use for basic flying and the 4 strokes for sport flying?????? because it has better performance?????
Either can be used for basic or sport flying. Performance is measured by power-to-weight and by power-to-displacement and 2cycles win both those comparisons. It is usually more difficult for a beginner to handle a 4cycle. It is harder to hear the change in speeds when setting the highspeed needle. For that reason, many engine experts recommend that a tachometer be used to set the carburetor needle. It's good advice.
I have a question, I think I am gonna get a cessna... it says it requires either an engine 2c .40-.45 or a 4c .60 Can I use a 2c .46 engine to fly it?????? or it's too big?????? I would prefer this because I want to train with this basic plane, just basic flying...... and then... when I feel ready or more skilled... I think I can get another plane and set up a 4c which will have better performance...... am I thinking right??????
You can often use larger engines than recommended. A 46 is basically in the 40-45 range in weight and power.
Forget the idea that a 4c gives better performance. They don't. A heavier, larger 4c can give equal aerodynamic performance however the extra weight will make that more of a challenge.
In aerodynamics, weight is a penalty.
When choosing an engine for a specific airplane, you need to consider what the engine weighs. That affects both the final weight of the airplane, which affects the climb performance. And it could cause you to need even more weight to balance the airplane. In a few cases, the extra weight is a benefit, such as for airplanes like the Sopwith Camel which will need quite a bit of weight up front.
Noone today chooses a 4C to race or fly combat who wishes to win. Precision aerobatics can be flown with either, but the airplanes have to be balanced to the engine's weight and some years only 2C was the 1st choice. But they both work in that event because the modelers tailor the airplanes to the engines. Basically there are no events where 4C engines are 1st choice for anything other than for their sound.
4C's however are fun just for themselves. Lots of the 4C bigots love them for what they are and what they do. Whatever that is.