Asking as an experienced "single engine" modeler, I'm curious to know if there are any rules of thumb, or formulas to determine the correct engine sizes for a multi engine model. For example:

For a single engine model of a known type, overall size, weight, and wing loading etc, a modeler can determine from experience what size engine will be required to achieve the desired performance. Let's say that in this case, our subject model is powered by a 60cc engine, and performance is satisfactory.

If we were to build another model of the same general specifications as the first, only this time the model is a tri-motor, would it simply be a matter of using the same amount of total combined displacement, of say three 20cc engines? Or even one 30cc and two 15cc?

I guess the question is, Are three 20cc engines going to put out more or less thrust than a single 60cc engine?


Cheers, Nigel