The McCulloch Model MC-4 was an American tandem-rotor

helicopter A helicopter is a type of rotorcraft in which lift and thrust are supplied by horizontally spinning rotors. This allows the helicopter to take off and land vertically, to hover, and to fly forward, backward and laterally. These attributes ...

and was the first helicopter developed by

McCulloch Aircraft Corporation __NOTOC__ The McCulloch Aircraft Corporation was the aircraft division of the McCulloch Motors Corporation. McCulloch acquired Helicopter Engineering Research Corp in 1951. It manufactured two innovative helicopter designs – the tandem-rotor ...

, a division of

McCulloch Motors Corporation McCulloch Motors Corporation is an American manufacturer of chainsaws and other outdoor power tools. The company was founded in Milwaukee, Wisconsin, in 1943 by Robert Paxton McCulloch as a manufacturer of small two-stroke gasoline engines and ...

.Harding, Stephen ''U.S. Army Aircraft Since 1947'', Airlife Publishing, Ltd. 1990. It was evaluated by the

United States Army The United States Army (USA) is the land service branch of the United States Armed Forces. It is one of the eight U.S. uniformed services, and is designated as the Army of the United States in the U.S. Constitution.Article II, section 2, cla ...

as the YH-30 and the United States Navy as the XHUM-1.

Design and development

The MC-4 was a larger version of the earlier HERC JOV-3 tandem-rotor helicopter and was developed by the McCulloch Aircraft Corporation. The JOV-3 was developed by Jovanovich when he headed the Helicopter Engineering and Research Corporation. The JOV-3 first flew in 1948. In 1949 Jovanovich moved to the McCulloch Motors Corporation where an enlarged helicopter the MC-4 first flew in March 1951. It was followed by a similar MC-4C and three evaluation helicopters for the United States Army (as the YH-30). The MC-4C was slightly larger than the MC-4. When the MC-4C was certified in 1953 it was the first tandem-rotor helicopter to be certified in the

United States The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territorie ...

for commercial use. Three examples were evaluated by the United States Army as the YH-30, but the Army's evaluation showed the helicopter to be underpowered. The YH-30 had a steel tube framework with a light metal skin, A single 200 hp

Franklin Franklin may refer to: People * Franklin (given name) * Franklin (surname) * Franklin (class), a member of a historical English social class Places Australia * Franklin, Tasmania, a township * Division of Franklin, federal electoral d ...

piston engine was horizontally mounted amidships and powered two intermeshing tandem rotors. It had a fixed-wheel tricycle landing gear with a castering nosewheel. No civil or military orders were received and Jovanovich formed his own company, the Jovair Corporation, where he modified the MC-4C as a prototype for a four-seat private helicopter designated the Sedan 4E. The Sedan 4E was powered by a 210 hp Franklin 6A-335 engine. A version with a turbocharged engine was designed as the Sedan 4ES and a more basic Sedan 4A for agricultural use. By 1965 a small number of Sedan helicopters were built. In the early 1970s, McCulloch regained the rights to the helicopter designs.

Variants

McCullough XHUM-1 (133818) (25970705102)

; McCulloch MC-4 : Prototype with a 165 hp Franklin engine, two built, one for evaluation by the United States Navy. ; McCulloch MC-4A : Variant for evaluation by the United States Navy as the XHUM-1, two built. ; McCulloch MC-4C : Prototype with a 200 hp Franklin engine, one built and an additional three for United States Army evaluation as the YH-30. ; Jovair Sedan 4E : Production civil four-seat version powered by a 210 hp Franklin 6A-335 engine. ; Jovair Sedan 4ES : Sedan with a turbocharged 225 hp Franklin engine. ; Jovair Sedan 4A : Simplified agricultural version.

Military designations

; YH-30 : Military version of the MC-4C, three built. ; CHUM-1 : Two MC-4As for evaluation by the United States Navy, later redesignated HUM-1.

Operators

; *

United States Navy The United States Navy (USN) is the maritime service branch of the United States Armed Forces and one of the eight uniformed services of the United States. It is the largest and most powerful navy in the world, with the estimated tonnage ...

Surviving aircraft

In 2008 two MC-4Cs were registered in the United States. The Pima Air and Space Museum in

Tucson, Arizona , "(at the) base of the black ill , nicknames = "The Old Pueblo", "Optics Valley", "America's biggest small town" , image_map = , mapsize = 260px , map_caption = Interactive map ...

has HUM-1, Bureau Number 133817, civil registration N4072K. The Yanks Air Museum in Chino, California has another HUM-1, Bureau Number 133818. Possibly N4091K. N4071K was purchased by Jovanovich and Kozloski then upgraded to the newer Jovair-4E Sedan design. It is currently dismantled in Switzerland. It was also used in the 1954 science-fiction movie 'Gog' from Ivan Tors. One of the three YH-30 military prototypes, c/n 001 with military serial number 52-5837, is preserved by the US Army Aviation Museum at Fort Rucker, Alabama. In December 2018, the aircraft had completed much of its restoration and by January 2019 it was on display at the Army Aviation Museum.

Specifications (YH-30)

References

* John Andrade, U.S.Military Aircraft Designations and Serials since 1909, Midland Counties Publications, 1979, (Page 121) * The Illustrated Encyclopedia of Aircraft (Part Work 1982-1985), 1985, Orbis Publishing, Page 2213/2214.

External links

Jovair history
{{USN helicopters 1950s United States experimental aircraft Tandem rotor helicopters 1950s United States helicopters Aircraft first flown in 1948 Single-engined piston helicopters