Those of us who own or rent airplanes are aware of the registration numbers, or N numbers, that each must carry. Few, however, realize that those numbers are not cast in concrete, but are transferable. An owner can cancel a number that came with his plane and replace it with one of his choice — provided, of course, that someone else isn’t using it.
Without exception, all of the floats seen on licensed civil seaplanes today are of the twin-float type. The single-float type popular with the U.S. Navy when it still had seaplanes, with small floats under the wingtips as on flying boats, has never been approved for civil operation.
One of the most memorable airplanes in the U.S. Navy inventory is the little Curtiss F9C “Sparrowhawk” of 1931-36. Aside from its distinctive gull-winged configuration and small size for a contemporary fighter, the F9Cs are best remembered for their unique role as auxiliaries to large rigid airships. They were actually carried aboard the Navy’s airships Akron and Macon.
In the last issue, we looked at the SA-1 (Ship’s Aeroplane) developed by the U.S. Naval Aircraft Factory at the end of World War I. Although an oldie with many features that were outdated even for 1919, it deserves more attention, as it has many features that are applicable to today’s homebuilts, both in the Ultralight and Experimental Categories.
A major design objective of the Naval Aircraft Factory SA-1 of late 1918 was to have as simple a structure as possible. This was achieved, but almost to the point of being crude in some areas. The structure, particularly in the fuselage, has some features well worth considering for today’s ultralights and the lower end of the “licensed” class.