# McCulloch MC-4

The McCulloch Model MC-4 was an American tandem-rotor helicopter and was the first helicopter developed by McCulloch Aircraft Corporation, a division of McCulloch Motors Corporation. It was evaluated by the United States Army 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 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 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
### 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

* United States Army
* United States Navy

## Surviving aircraft

* 133817 – HUM-1 on static display at the Pima Air and Space Museum in Tucson, Arizona.
* 133818 – HUM-1 on static display at the Yanks Air Museum in Chino, California.
* 52-5837 – YH-30 on static display at the United States Army Aviation Museum at Fort Novosel, Alabama.

## Specifications (YH-30)

General characteristics
* Crew: two
* Length: 32 ft 0 in (9.75 m)
* Height: 9 ft 2 in (2.79 m)
* Empty weight: 1,200 lb (544 kg)
* Gross weight: 2,000 lb (907 kg)
* Powerplant: 1 × Franklin O-335-6 (6A4-200-C6) piston , 200 hp (147.1 kW)
* Main rotor diameter: 2 × 22 ft 0 in (6.71 m)
Performance
* Maximum speed: 105 mph (168.98 km/h, 91 kn)
* Range: 200 mi (321.86 km, 170 nmi)