65 years ago on this day, the Bell XH-40 helicopter made its first flight.
The Bell XH-40 first flight
After positive experiences during the Korean War with rotorcraft, the US Army decided to invest in the development of helicopters. In 1955 Bell Helicopter, funded by the US Army, began working on a prototype helicopter powered by a turbine engine (Lycoming LTC1B-1 (XT53-L-1)). Testing of the engine and airframe combination was done in the Model 47 (XH-13) helicopter. After successfully completing these tests a larger aircraft, the model 204, was the next step. As it was used for military testing it received a military designation, XH-40. Some specifications for this prototype;
Fuselage Length 39' 4" (`12.29 meters)
Toatl length (rotor turning) 53' 4" (16.26 meters)
Maximum height 14'7 " (4.45 meters)
Empty weight 3693 lbs (1675 kg)
MTOW 5650lbs (2563 kg)
Powerplant Lycoming LTC1B-1 (XT53-L-1) 770 shp 860 shp at 21510 rpm 102 lbs of thrust at Military power
Vmo At 2400 ft; 133 knots (153 mph - 246 kph) At 5000 ft: 125 knots (144 mph - 232 kph)
Service ceiling 21.600' (6584 meters
Fuel capacity 165 gallons (625 liters)
Range 212 miles (241 km)
After completing its first flight, on this day in aviation history, another two prototypes were built. By 1958 a total of six aircraft were delivered to the US Army for testing. Some had a lengthened cabin, they designated YH-40.
With testing completed Bell tweaked the design and the US Army took the YH-40 into service. When it entered active service the US Army changed the designation to UH-1 Huey.
A rare color photograph of a prototype Bell XH-40, hovering. A stabilizer bar is installed, and the synchronized elevator has end plates similar to those on Bell Model 47 helicopters.
The aircraft, as it was taken on by the US Army, had a two-crew side-by-side configuration, crewmembers had hinged doors on either side for access. The cabin had sliding doors. The engine was mounted on top and behind the cabin and drove a two-bladed main rotor and a two-bladed tail rotor.
This would be the start of a long service life for the UH-1 family of helicopters. A total of 16 helicopter variants would be developed and built over the years since then, with the latest variant, the UH-1Y Venom, being the latest one. This is a twin-engine version of the UH-1N Twin Huey. It flew for the first time in November 2006 and is used by the US Marines.
A UH-1Y Venom
Specifications for the latest family member the UH-1Y Venom;
Capacity: 6,660 lb (3,021 kg) / up to ten crashworthy passenger seats / six litters / equivalent cargo
Length: 58 ft 4 in (17.78 m)
Height: 14 ft 7 in (4.45 m)
Empty weight: 11,840 lb (5,371 kg)
Max takeoff weight: 18,500 lb (8,391 kg)
Powerplant: 2 × General Electric T700-GE-401C turboshaft 1,828 shp (1,363 kW) each for 2 minutes 30 seconds 1,546 hp (1,153 kW) continuous
Main rotor diameter: 48 ft 10 in (14.88 m)
Main rotor area: 1,808 sq ft (168.0 m2)
Maximum speed: 164 kn (189 mph, 304 km/h)
Cruise speed: 158 kn (182 mph, 293 km/h)
Vmo: 198 kn (228 mph, 367 km/h)
Combat range: 130 nmi (150 mi, 240 km) with 2,182 lb (990 kg) payload
Endurance: 3 hours 18 seconds
Service ceiling: 20,000 ft (6,100 m)
Rate of climb: 2,520 ft/min (12.8 m/s)