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Let’s give this What If thing a try….. I am not a What If builder at all, so this is something new for me. However, my (late) entry is based on a study if it could be done – converting a Grumman Widgeon to turbine power. Most of Grumman’s amphibian models have been converted to turbine power; the Goose, Mallard and Albatross come to mind. The Widgeon being the smallest though makes a bit of a challenge, as Turbines in that power range are not all that common. On the low end of the spectrum are the PT6A and Walter 610 engines as options, that are usually used for that purpose. Both are about 3 times as powerful as the original piston engines installed. But then again, it is all about more power…. Converting an aircraft from piston to turbine is not all that simple as replacing the engine. Balance is an obvious problem, but there are control and power effect problems that need to be considered as well. The concept that I came up with is this: Stretch the fuselage ahead of the wing to make up for the slightly lighter engines, but also stretch the rear fuselage a bit – to increase control authority of the tail feathers. Or increase the “tail volume” as it is technically called. The trick is finding a balance between the two. Increasing the tail authority is required due to the increased power, to allow controlled flight with one engine out and to also counteract the now increased aerodynamic forces the extended nose will give. Also a fin root extension will be given for the latter reason to help in cross wind landings. The engine nacelles have to be extended a bit to fit the turbine engines. And also to keep the prop discs ahead of the flight crew stations in the now extended front fuselage. To start off with, first some calculations: I created a simple 3D numerical model of the fuselage that could be stretched at arbitrary points. The resulting moment generated by the new fuselage and relocated engines was calculated and compared to the original intended moment around the wing. I played around with these variables till I found a solution that I was happy with. See the picture below that compares the original (short) fuselage to the new extended one. Front extension is 1.00 metres and the rear extension is 0.4 metres. That together with the slightly lighter engines on an 0.65 metre extension give a balance around the original balance point. Then for the kit: I had this old Airfix kit lying around, built many, many Moons ago and in a sorry state. It was used as a paint test bed and then forgotten. First thing I did was give it the brake fluid treatment to get rid of the thick layers of paint and dissolve the glue joints. Here the parts after the treatment: Next up is cutting the fuselage on the stations where the extension pieces will fit. R