Experimental Planes: The Tiltwing LTV XC-142 | Ling Temco Vought V/STOL Aircraft That Never Was
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- Опубліковано 6 жов 2024
- The Ling-Temco-Vought (LTV) XC-142 was a tri-service tiltwing experimental aircraft designed to investigate the operational suitability of vertical/short takeoff and landing (V/STOL) transports. An XC-142A first flew conventionally on 29 September 1964, and on 11 January 1965, it completed its first transitional flight by taking off vertically, changing to forward flight and finally landing vertically. Its service sponsors pulled out of the program one by one, and it eventually ended due to a lack of interest after demonstrating its capabilities successfully.
In 1959 the United States Army, Navy and Air Force began work on the development of a prototype V/STOL aircraft that could augment helicopters in transport-type missions. Specifically they were interested in designs with longer range and higher speeds than existing helicopters, in order to support operations over longer distances, or in the case of the United States Marine Corps, from further offshore. On 27 January 1961, a series of DOD actions resulted in an agreement where all of the military services would work on the Tri-Service Assault Transport Program under the Navy's Bureau of Naval Weapons (BuWeps) leadership.
The original outline had been drawn up as a replacement for the Sikorsky HR2S, with a payload on the order of 10,000 lb (4,500 kg). BuWeps released a revised specification that specified the same payload, but extended the operational radius to 250 miles (400 km) and increased the cruising airspeed to 250-300 knots (460-560 km/h) and the maximum airspeed to 300-400 knots (560-740 km/h). However, for the Marine Corps mission, the requirement stated that the fuel load could be reduced so that the maximum gross weight would not exceed 35,000 pounds (16,000 kg), as long as a 100-nautical-mile (190 km) radius was maintained.
Vought responded with a proposal combining engineering from their own design arm, as well as Ryan and Hiller, who had more extensive helicopter experience. Their proposal won the design contest, and a contract for five prototypes was signed in early 1962 with first flight specified for July 1964. The design was initially known as the Vought-Ryan-Hiller XC-142, but when Vought became part of the LTV conglomerate this naming was dropped.
During the prototype development the Navy decided to exit the program. They were concerned that the strong propeller downwash would make it difficult to operate. Their existing HR2S fleet had a ground pressure of about 7.5 psi (500 hPa), and proved to blow people about on the ground and stir up considerable amounts of debris. The C-142 was predicted to have an even higher loading of 10 psi (700 hPa), which they believed would limit it to operations to and from prepared landing pads and was therefore unsuitable for assault operations.
During testing the aircraft's cross-linked driveshaft proved to be its Achilles heel. The shaft resulted in excessive vibration and noise, resulting in a high pilot workload. Additionally, it proved susceptible to problems due to wing flexing. Shaft problems, along with operator errors, resulted in a number of hard landings causing damage. One crash occurred as a result of a failure of the driveshaft to the tail rotor, causing three fatalities. One of the limitations found in the aircraft was an instability between wing angles of 35 and 80 degrees, encountered at extremely low altitudes. There were also high side forces which resulted from yaw and weak propeller blade pitch angle controls. The new "2FF" propellers also proved to generate less thrust than predicted.
General characteristics
Crew: 2
Capacity:
32 fully-equipped troops or
24 stretcher patients and 4 attendants or
8,000 lb (3,600 kg) cargo
Length: 58 ft 1 in (17.70 m)
Wingspan: 67 ft 6 in (20.57 m)
Height: 26 ft 1 in (7.95 m)
Wing area: 534.5 sq ft (49.66 m2)
Aspect ratio: 8.6:1
Empty weight: 22,595 lb (10,249 kg)
Gross weight: 34,474 lb (15,637 kg) (VTOL weight)
Max takeoff weight: 44,500 lb (20,185 kg) (STOL)
Fuel capacity: 1,400 US gal (1,200 imp gal; 5,300 L)
Powerplant: 4 × General Electric T64-GE-1 turboprops, 2,850 shp (2,130 kW) each
Propellers: 4-bladed Hamilton Standard variable-pitch propellers, 15.5 ft 0 in (4.72 m) diameter
Performance
Maximum speed: 431 mph (694 km/h, 375 kn) at 20,000 ft (6,100 m)
Cruise speed: 288 mph (463 km/h, 250 kn) at sea level
Combat range: 230-470 mi (370-760 km, 200-410 nmi)
Ferry range: 3,800 mi (6,100 km, 3,300 nmi)
Service ceiling: 25,000 ft (7,600 m)
Rate of climb: 6,800 ft/min (35 m/s)
#aircraft #vtol #XC142
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Despite its design issues, the XC-142 proved to be an important step in the evolution V/STOL technology development as this aircraft led to the design of the V-22 Osprey. The one aircraft remaining at the Air Force Museum is worth a look
it's funny too because we got the V/STOL V22 Osprey which still suffers from the vibration and cross shaft issues and has killed a lot of people due to problems with that system
@@wildcoyote34 I think that is not so funny.
@@Stefan_Dahn that was sarcasm
Saw that plane in hover mode several times. Drove right by LTV and airfield to and from college campus at Arlington.
Thanks for bringing us epic X planes documentaires like this one .
Glad you enjoyed it!
I volunteer at the National Museum of the US Air Force and know this aircraft well!
👍👍
Its nice to know that the US also suffered from short sightedness and impatience with the development of new aircraft! The outcome, the waste and scrapping of a viable and useful VTOL transport plane. If only they had persevered with it, it could have paved the way for a V22 type version much earlier, and at a much, much less development cost! There's an old saying in the UK about the British Aerospace mentality, things always have to be done twice, to get it right the first time! Sounds like the US suffers from this mentality too!
Unlike russia the U S is not afraid to start over. Things have not changed since the days of the ussr. The russians will keep any piece of crap that doesn't perform well and try a fix that normally would back to the drawing board for most countries. The Caspian sea monster is one of the few times that a project was.scrapped, without being reengined or had 2 feet of the body added or removed.
Honestly, this wasn't even the best configuration. The best configuration was still a 4 prop design, but they were ducted (which isn't too important), and distributed across 2 wings (fore and aft) instead of 1, which gives better control options.
Skunk Works at Lockheed - it would be fascinating to see what they would have come up with on the XC-142 considering their unique and novel approaches to the many problems with futuristic aircraft they successfully developed.
Looks suspiciously like a 4 engine version of the Canadian vertol.
It came before the cl-84. It was a development of the holler xc-19.
Looks like a b17 wanted to become a vtol
Excellent video but 400 liter fuel capacity isn't enough to get it off the ground.
No kidding. Four 3000 hp turbines are going to such that up in a hurry.
Less fire load in case of crash. The engines have 8500 kW. At 300 g/kWh and full throttle, they take 8,500 kW * 0.3 kg/kWh {estimated} = 2,550 kg/h = 42 kg/min or ~56/min. With a 400 Liter tank it flies ~7 min to bingo fuel (calculated with 0.75 kg/l).
Aircraft in game pv the private vtol
Someone please send this to Ramee