Good afternoon gentlemen just joined your forum. Looks to be filled with many knowledgeable people.

My question is: Im am just going to start delving into giant scale aircraft & I know very little about gas engines.
I'm going to be building A Top Flite P51 D giant scale and I need to know what size engine will work well in it?

I always went 2 sizes larger in my smaller airplanes and that always worked great, but with the gas engines I have no idea where
to start .

So any info you could provide would be greatly appreciated.

thank you
Robert

WHile I am not an engine expert, I would get RPM data and weight data for the engines you are looking at. Buy an engine that will allow you to balance the plane and if it is one of the newer designs, you will have more than enough power.

The T/F giant 51 will fly quite well on a Zenoa G-62. This is the heaviest of the gassers for its' size and output. You may need the weight in the front for balance purposes.

If you don't need the weight, might I suggest a good, high output 3.2 ci engine. My personal choices are Brisson, BME, and Taurus.

For good performance purposes, try about 1 cubic inch for each 8 pounds of weight. That will be for the all up, ready to fly weight. I like to add a couple of imaginary pounds for general purposes.

Thank you both for replying so quickly.
Both of your suggestions sound very good and I will start off in that direction.

Robert