Bell Model 68 X-14
Back to the Virtual Aircraft Museum
  VTOL AIRCRAFTVirtual Aircraft Museum / USA / Bell  

Bell Model 68 X-14

Although the ATV had never completed a full transition, it was considered a successful experiment for it proved the feasibility of a jel-powered VTOL aircraft and attracted the interest of the Air Force. Bell then decided to follow on by designing a completely new test-bed aircraft with enlarged capabilities. In July 1955, a new programme was initiated with the awarding of an Air Force contract to Bell for VTOL research which eventually led to the designing of the Bell Model 68 or X-14.

The design team, led by M McEuen, worked fast so that assembly of the unique prototype could be undertaken within three months. The X-14 was an open-cockpit mid-wing monoplane of all-aluminium construction. It was powered by two 707kg Armstrong Siddeley Viper 8 axial-flow turbojets mounted horizontally side-by-side in the forward fuselage. Thrust diverters were mounted behind the engines (in place of the original tailpipes) to deflect the jet thrust towards the ground during take-off and landing. The X-14 was thus able to raise itself vertically off the ground by direct jet lift, with its fuselage still in the horizontal position. At a safe height, the jet thrust was to be deflected slightly rearward to produce a forward thrust in addition to jet lift. When the forward speed was considered sufficient for the fixed wings to provide lift all the thrust was directed aft and the aircraft could fly in a conventional manner. During take-off, landing, hovering and flight at low speeds, directional control was effected by means of compressed-air nozzles located at the wingtips and tail.

Much of the aircraft was assembled from various existing aircraft components. A Beechcraft Model 35 Bonanza provided the wings, parts for the undercarriage and ailerons, and a Beechcraft T-34A Mentor provided the tail section. Ground testing was begun in October 1956 by which time the engines and exhaust nozzle system were under test at All-American Engineering. During the ground testing, it was discovered that the arrangement of the exhaust system created a low-pressure area just beneath the aircraft preventing takeoff. This problem was overcome by lengthening the undercarriage by 0.6m.

On 17 February, 1957, just over 18 months after go-ahead, the X-14, flown by Bell test pilot Dave Howe, completed its first successful hovering flight at Bell's Niagara Falls facility. This maiden flight was followed in June by the first partial transition and by the first complete VTOL cycle on 24 May, 1958. The aircraft was then taken on charge by the Air Force, which turned it over to NASA. The X-14 was received by NASA at Ames Research Center (Moffett Field, California) on 2 October, 1959, but the preliminary flight-test programme indicated that it was seriously underpowered. A modification programme was initiated to increase power: the two Armstrong Siddeley Viper 8 turbojets were replaced by two 1215kg General Electric J85-GE-5s, which virtually doubled the available thrust.

Designated X-14A and registered N234NA, the aircraft was back in the flight-test programme in 1961 and began exploring several specific areas such as V/STOL handling qualities and control concepts. The X-14A participated in various research programmes for the next eleven years when its J85-GE-5s were replaced by 1368kg J85-GE-19s and a programmable computer permitting duplication of the flight characteristics of various VTOL aircraft was installed (the X-14A then becoming known as the X-14B). The aircraft flew with its new engines in February 1971 and was used for ten more years. More than 25 test pilots came from around the world to fly the X-14B to gain experience before proceeding to other V/STOL prototypes. Neil Armstrong once flew it as a Lunar lander.

These test flights continued until 29 May, 1981, when the X-14B was victim of a hard landing accident which occurred following loss of roll control while making a ramp hover. The problem was traced to saturation of the VSCAS (Variable Stability Control Augmentation System) autopilot roll servos. The landing caused the collapse of the main undercarriage and ruptured a fuel tank. The tail was seriously damaged in the ensuing fire. Fortunately, the pilot, Ron Gerdes, escaped uninjured. Following this accident, the X-14B was never flown again and the necessary repairs were never made. It was put into temporary storage at NASA Ames Research Center and, in February 1989, was shipped to the US Army Air Museum at Fort Rucker in Alabama.

Alain J Pelletier "Bell Aircraft since 1935", 1992

Bell Model 68 X-14

    Take-off weight1934 kg4264 lb
    Empty weight1437 kg3168 lb
    Wingspan10.30 m34 ft 10 in
    Length7.92 m26 ft 0 in
    Height2.68 m9 ft 10 in
    Wing area16.68 m2179.54 sq ft
    Max. speed277 km/h172 mph
    Ceiling5500 m18050 ft
    Range480 km298 miles

Bell Model 68 X-14A three-view drawing (1314 x 1270)

GC, 22.11.2012


I'm surprised you didn't know that North American built the X-15, not Bell.

hualunjia, 21.06.2011

I am surprised that there is no mention of the most outstanding of the Bell "X" planes the Bell X15.

, 21.06.2011

Bell Model 68 X-14

Alex Morton, 24.01.2011

Ron Gerdes was a very close and personal friend of mine, along with his lovely and gracious wife Lois. I worked at ESL adjacent to Moffett Field. I would see the X-15 take off and later hover over the field for minutes at a time. Being a Christian and prone to prayer for my fellow man- I prayed for the safety of the unknown pilot of the X-15. One day I was mentioning my experience to Ron about my praying for the brave pilot. He said "Thank you- that was me you prayed for!!!" Blew me over, I'll tell you.
Both are now with the Lord - both having died of cancer. He was a man's man. An honest person to the hilt. He and I would tell war stories late into the night...Him being a Naval aviator and me a WWII Air Cadet (I was a little older than he!...I'm 84)- either at his house or mine first at Sunnyvale, CA and then at Mt. Hermon,CA. We both went to Valley Church in Cupertino,CA where Lois played the organ. She was a registered nurse and a good one I can attest from personal encounter with her professionally.
Lots of good memories from Ron and Lois. A tribute to them I give via this message.
Sincerely, Alex Morton

Bill Davies, 19.10.2010

Perhaps the other Bell "X" airplane should be mentioned in this series - the dreaded X-22A, which I, and others flew.

Bruce, 21.06.2010

The X 14 airframe is now at the Ropkey Armor Museum Crawfordsville IN As part of a very nice military display.

Art Deco, 25.06.2009

The Bell X-15 was built by North American Aviation so, in fairness, they listed it there.

Barry, 25.06.2009

I am surprised that there is no mention of the most outstanding of the Bell "X" planes the Bell X15.

Barry, 25.06.2009

I am so surprised that you have not included any mention of what was the most outstanding of all the Bell "X" planes the Bell X15.

Do you have any comments about this aircraft ?

Name    E-mail


All the World's Rotorcraft

Virtual Aircraft Museum

All rhe World's Rotorcraft AVIATION TOP 100 -