Using plastic shrinkable (PET) bottles to craft an aerodynamic and pleasing to the eye, engine cowl on a model aircraft.
Step 1: Design Thoughts
Once you have the basic fuselage its time to figure what motor you're going to be using and how its going to be mounted. Once thats taken care of, then you can begin with the cowl.
Points to consider:
Streamlined for aerodynamic considerations
Blend in with the fuselage
Have some vent holes for oncoming air to cool the motor.
In my case Im using an electric speed 400 which can get hot if totally enclosed, so I need some air flow past the prop and an escape outlet in the fuselage to prevent pressure buildup, which might cause the covering to balloon.