Gnow,
Totally disagree that "the will have a very good chance of flipping over due to the moment created by the undercarriage if it is bolted down".
Retractables are a relatively modern introduction in the helicopter world. Overwater flight, and ditchings, with fixed undercarriage have gone on for decades; either the whole airframe digs in and turns turtle, or the pilot flares to a near zero airspeed, as taught, and pops the floats. U/C position has little effect on the outcome.
Spot the difference: the only thing I recall is that the brakes didn't work too well.....
