Consolidated Amphibian

The latest achievement of the Consolidated Aircraft Corporation is the building of the world's largest amphibian, the Model 28-5A, or as designated by the Navy, the XPBY-5A. The new amphibian is basically the familiar Model 28 twin-engine flying boat, better known by its Navy designation, PBY. The change was accomplished chiefly by the addition of a tricycle landing gear which is fully retractable. The side wheels and supporting mechanism, complete with oleo shock struts, retract into wells in the side of the hull. The nose wheel in the retracted position is completely closed over by automatically operated hatches so that no resistance to planing is encountered. All three wheels are operated by a central hydraulic power drive, which handles all the necessary operations in sequence automatically and both the extension and retraction of the gear is controlled by a single lever. Hydraulic pump power is obtained either from the main power plant or from an auxiliary engine, but hand operation is possible, if necessary.

The landing gear has a number of advantages in addition to the obvious one of greatly extending the scope of utility for the Model 28. For rough water taxiing the extended gear greatly assists in control by serving as a sea anchor. More engine power may be applied for short turns without undue acceleration, and turns on the water may be accomplished with far less skidding. Naturally, all danger of scraping the keel on the ramp is eliminated, and no beaching crew is required, for the ship can climb a ramp or beach under its own power. It may operate from sand beaches with no special ramps or facilities for handling.

Since the side wheels are above water when the ship rises on the step, and since automatic means are provided for expelling water from the closed bow wheel hatch before the plane is in the air, the flying trim remains unaffected. Repairs or routine servicing to the landing gear may be made with a minimum of trouble. The beaching gear lugs of the Mode 28 have been retained, so that standard beaching gear may be attached and the plane run out of water. This lifts the landing gear clear of the ground so that any servicing may be carried out.

This article was originally published in the "Flying Equipment" column of the January, 1940, issue of Aviation magazine, vol 39, no 1, p 49.
Photo is not attributed.