Vought V-173 (Flying Pancake)

History

Charles Zimmerman (1908-1996) was an aerospace engineer for most of his life, working at the Langley Memorial Aeronautical Laboratory during the 1930s before World War II. One of his more radical concepts was the V-173 "flying pancake" in the early 1940s, which actually led to the U.S. Navy's serious interest in fighters like the XF5U-1.

Zimmerman came up with a unique design around a wingless frame with a circular overall appearance (hence the genre's nickname of "flying pancakes"). The low-drag design is designed to take advantage of the propeller wash force that naturally occurs along the surface of the aircraft and to greatly improve the principle of lift. Such a design is thought to allow for shorter takeoff and landing times - a key component of maritime carrier fighter jets.

In many ways, this could lead to the realization of the vertical take-off and landing (VTOL) concept, which utilizes the vertical hover dynamics of helicopters and the on-demand forward motion of traditional fixed-wing aircraft.

Zimmerman's original vision involved a front engine that drove the propeller. In addition to this, there is a sloping cockpit position to encourage the slimmest front profile and maintain maximum aerodynamic efficiency. Zimmerman and his team produced a scale model of the concept for testing.

In 1937, Zimmerman joined Vought as a consultant, bringing the circular low-drag concept, for which he was awarded the construction of a larger electric remote-controlled testbed, named "V-162".

At this point, the U.S. Navy is watching what is happening in Europe, driven largely by German aggression. As a result, many plans began to attract the attention of the authorities, as all-out war in Europe could only be avoided for so long for the United States. In 1939, the V-162 concept attracted enough interest in the Navy to warrant a limited development contract with Vought for a full-fledged technology demonstrator.

This product then became the V-173 and was referred to as "VS-135" by the Bureau of Naval Aviation (BuAer).

The V-173 took the form established by the previous V-162, expanding its size and ultimate goal. The pilot's prone position was never practical compared to military fighter jets, but was abandoned in favor of a more traditional upright seat. The fuselage structure is primarily made of wood with fabric overlays, and propulsion is provided by a pair of horizontally opposed 80 hp Continental A-80 4-cylinder engines, each driving a three-bladed propeller (the original design featured two propeller). The engine is buried in the fuselage, requiring the use of a linkage shaft system to drive the blades.

These lamellae are anchored to the unobstructed view of the cockpit along structural protrusions on the leading edge of the fuselage. To accommodate the required 16.5-foot rotating blade spacing, the fuselage was fitted with a fixed "trailer" landing gear with two single-wheeled main legs.

A pair of vertical stabilizers are mounted at the stern, like a traditional horizontal plane. However, the V-173s lacked true main wings, making them a very unorthodox way of fighting.

The development of the V-173 was slower than expected, and the program received very little funding from the US Navy. At the end of 1941, the fuselage was taken to the wind tunnel for testing in its original form, which required the addition of some additional devices - ailerons, so to speak, which combined the functions of ailerons and elevators. The engine received the attention it deserved until mid-1942.

On November 23, 1942, the aircraft, engine and all components made its maiden flight.

In testing, the prototype demonstrated excellent short-range quality and handling, but lacked the required combat performanceit could only reach speeds of nearly 140 mph, with a steep drop in speed. The program suffered at least two forced landings, but no casualties. The prototype was also able to demonstrate a rate of climb of 5,000 feet in seven minutes. Further design changes followed, of which the U.S.

Navy was so interested that it agreed to a prototype for a military version. This became the XF5U-1, described elsewhere on this page.

The V-173 continued a long development effort, with a total of 190-200 test flights (sources vary) by 1947, although the war ended in September 1945. She officially retired from testing service on March 15, 1947.

The unique V-173 prototype was preserved from a post-war scrap yard and is currently owned by the Smithsonian Group for a full restoration.

Specification

Basic

Production

Roles

Dimensions

Weight

Performance

Performance

Armor

Changes