Hi all I'm new to R/C would like to pick someone brain, 1. How do you determine what size nitro you use on a plane.
2. and I guess the size of the engine will determine what prop is used.
Thank
Bill

Bill, if you have purchased a kit or ARF it should say on the box. If you bought used-you will have to figure a couple things like weight and wing area. Planes with a high wing configuration typically can use a smaller engine than say a sporty low wing model. 2 stroke engines will offer more power than 4 strokes so theirs something else to consider. Tell us what you have or are looking at.

If you see a plane in the 40 size category then you know it will fly on a 40-46 size engine. You"ll have to increase engine size to get equal power to the 2 stroker if you go for a 4 stroke. A 70 4stroke will be a good replacement for a 46-52 size 2 stroke.

Thanks frenchie and murdoc,
Not sure just what plane I want,thought of a kit or maybe ARF. I just though maybe there was a rule to thumb on size of plane and the size of the engine.
Thanks alot
Bill

I believe that if you can swing it get the biggest engine recommended...in other word .60 to .90 get thew 90

I'm an intermediate flyer and find this question to be interesting to me. So many will say, put the biggest engine you can into the plane, and maybe even the next size bigger. I learned how to fly RC with a Sig Kadet Senior that I built and I have a Thunder Tiger GP42 in it. That's a 78" high wing trainer, and now that I look at it, the GP42 looks small in it, but it flew it fine, I had a blast with it, could fly really slow and pretty much taught myself to fly with it. I still have it, and it still looks good as well in flyable condition. My next plane was an Avistar, another Thunder Tiger GP42 was used, I flew the heck out of that plane. Many put a 46 into Avistars, but I never felt I needed a "rocket". It flew fine on a GP42. It was also more economical to run compared to my TT PRO 46. The engines made today are much better than what was produced 15 years ago. A strong 46 today is like what a 60 was years ago. So I'm not convinced if the kit box says 40-55, that the best solution is the 55. It's probably personal prefference that is the main difference. So many things have to be taken into consideration. The plane itself, how you like to fly (a rocket with wings or fly on the wings), what you want to do with the plane, altitude of your field etc. I would say, it's probably not a good idea to choose the smallest engine size. I can't imagine my Kadet Senior with a 29 on it. Probably would fly, but I fly off of a grass field and that's another thing to consider. Definitely be within engine size the model suggests, don't be on the low end of that scale. I'd like to hear others thoughts.

I'll second that!

The longer you're in the hobby, the more intuitive this becomes. You'll develop your own flying style and interests, and those will lead you to certain airframe/engine combinations. The best thing to do is experiment and watch other flyers. In general, pay attention to the weights involved. If you read that a plane is often nose heavy, you'll want to find a lighter engine. This might mean a slightly smaller engine, where you have less weight all-over than if you'd use a heavy engine and had to add tail weight. The opposite is true for models that tend to be tail heavy.

So, in large part the answer is: "It depends." Do your research here and find out what people are using.

Tom...look at it this way...just because you can go fast doesn't mean you have to....I like to fly at 1/2 throttle....then advance the power for aerobatics.....Or tis better to have the power and not need it, than to need the power and not have it....
I can name one airplane that friend of mine has...he put the smallest engine recommended and the airplane just barely flew...
I have seen those guys that go a size bigger than recommended and fly full throttle all the time as well...as you say to each his own
Good Flyin to ya

My sentiments exactly I was always told to go the highest spec ie 30to50 Go towards the 50 as for prop size you can find a chart @TOP FLITE (Power Point Prop Chart)

Bigger the better, you don't have to fly full throttle. But, if you get into trouble and need the power to pull out, it's there. Nothing like trying to pull out of a jam and you don't have the power.

Definitely don't use the smallest engine recommended by the model manufacturer.