Bell XF-109

Infobox Aircraft
name=D-188A XF-109 / XF3L
type=VTOL fighter
manufacturer=Bell Aircraft Corporation


caption=XF-109 mockup with engine pods rotated for vertical flight.
designer=
first flight=
introduced=
retired=
status=Cancelled 1961
primary user=United States Air Force
more users=United States Navy
produced=
number built=1 mockup
unit cost=
variants with their own articles=The Bell XF-109/XF3L was a proposed eight-engine Mach 2-capable vertical take-off and landing (VTOL) fighter that never proceeded past the mock-up stage.

Development

If it had been built, the Bell D-188A project would have been one of the most unorthodox aircraft to fly, and certainly the most unusual in USAF inventory. In 1955, Bell Aircraft was requested by both the USAF and the USN to develop a VTOL/STOVL supersonic, all-weather fighter-bomber and defence interceptor. The project was highly ambitious and was designed to fulfill a multitude of roles for two different services and, as a result – based on the poor record of other Air Force/Navy aircraft projects – it is highly dubious as to its success. The aircraft was designated the Model 2000, and was offered in two different versions – the D-188 for the US Navy and the D-188A for the USAF. Bell had – rather optimistically – called the Navy version the XF3L-1 and the Air Force version the XF-109, although neither of these was official. On December 5, 1960, Bell publicly showed off the design as the XF-109 – the USAF version, as the USN had lost interest the year earlier.

The aircraft was unconventional, and consisted of a long, thin, area ruled fuselage with a large fin and all-moving stabilators in the tail. The single-person cockpit was in the extreme nose and the small-span wing was mounted high on the fuselage. At the ends of each wing were pods that contained two turbojets each. These pods were designed to swivel through an arc of 100 degrees to allow for both horizontal and vertical flight. To take off vertically, the pods were rotated to direct the engines’ thrust downward, while for horizontal flight the pods were rotated back to the horizontal. The pods were capable of directing thrust slightly forward as well for enhanced landing manoeuvres. In addition to the four wing engines, four additional engines were mounted in the fuselage – two in the rear directed out of two separate tail ducts, and two directly aft of the cockpit and positioned vertically to aid in VTOL flight, exhausting out of two ventral ducts. Thus, with eight engines, the XF-109 would have had the most engines ever fitted to a fighter aircraft.

Armament consisted of two 20mm cannon in the fuselage, an internal weapons bay and eight wing hard points for missiles and other ordnance. In addition, the D-188A featured an engine bleed system to assist in VTOL manoeuvring. Bleed air from the fuselage engine compressors would have been directed to a pair of thrusters in the nose and two more in the tail to aid in pitch, roll and yaw. However, in the spring of 1961, the USAF cancelled the program and no examples were built.

One final word on the designations. As mentioned, the military designations were not official and were speculative on the part of Bell. The Navy’s XF3L-1 was not assigned, but would have been the D-188’s designation had the aircraft been built, as this was the next in the USN series. The USAF XF-109 designation had previously been assigned to a proposed Convair F-106B variant, however, had subsequently been left blank and Bell assumed – if the D-188A had been built – that this would have been assigned to the aircraft. Many reference works refer to the D-188A by its assumed experimental series number, but in fact the XF-109 designator was never assigned.

pecifications (XF-109/D-188A, as designed)

aircraft specifications

plane or copter?=plane
jet or prop?=jet

crew=1
length main=58 ft 7.5 in
length alt=18.90 m
span main=23 ft 9 in
span alt=7.24 m
height main=13 ft 1.5 in
height alt=3.89 m
area main=194 ft²
area alt= m²
empty weight main=13,800 lb
empty weight alt= kg
loaded weight main=23,917 lb
loaded weight alt=10,849 kg
max takeoff weight main=
max takeoff weight alt=
engine (jet)=General Electric J85-GE-5
type of jet=turbojets
number of jets=8
thrust main=2,600 lbf
thrust alt=11.6 kN
max speed main=Mach 2.3
max speed alt=
range main=2,000 nm
range alt=2,300 mi, 3,900 km
ceiling main=60,000 ft
ceiling alt=18,000 m
climb rate main=
climb rate alt=
loading main=
loading alt=
thrust/weight=0.87
guns=4× 20 mm (0.787 in) cannon
rockets=108× 2.75 in (70 mm) rockets
bombs=4,000 lb (1,800 kg)

References

Townend, David R. "Clipped Wings – The History of Aborted Aircraft Projects", Markham, Ontario, AeroFile Publications, 2007, ISBN 978-0-9732020-4-5.

ee also

aircontent
related=
similar aircraft=
* EWR VJ 101
sequence=
lists=
* List of fighter aircraft
* List of military aircraft of the United States
see also=