09Omega

Not true at all! You can build an aircraft weighing up to 12499# and classify it experimental. The limit for ultralight is under 254# and none of these 7/8 scale planes are that light. In addition, all aircraft are subject to the same FAA regulations although experimental may have a few extra hoops to jump through. The real reason these aircraft are built to 7/8 scale is that the engines used in the original aircraft produced much more thrust than their modern counterparts. A typical Fokker DR1 had a 110hp Oberussel that swung a 9 foot prop. This produced considerable more thrust than a modern 0235 108 Hp Lycoming with a 6ft prop. Modern engines spin at 2700rpm for max hp. this is too fast for the big props. If you put the 108hp Lycoming in a full size Dr1 it would be very underpowered and dangerous. Thus the reason you build a 7/8 scale Dr1 and the 108hp engine is just right. The full Scale planes need either the real engine...Qubic bucks, or a really big modern Lycoming that just will not fit in that small cowl. Omega