Very brave. Put a turbine in it and forget your problems.

Alternatively, get a download of FMS, or any other good model airplane simulator with a half decent physics engine in it. Create a model with the same geometry as the one you are planning and model the power plant until it has the performance that you require.

If you are modelling ducted fans, ensure that you make the model realistic. They are truly horrible and have no redeeming features apart from not having an exposed propellor, a feature that only a scale modeller could love.