Handley Page Heyford

infobox Aircraft
name = HP.50 Heyford
type = heavy night bomber
manufacturer = Handley Page Aircraft



caption =
designer =
first flight = 12 June 1930
introduced = 1934
retired =
status =
primary user =
more users =
produced =
number built = 124
unit cost =
developed from =
variants with their own articles =

The Handley Page Heyford was a twin-engine British biplane bomber of the 1930s. Although it had a short service life, it equipped several squadrons of the RAF as one of the most important British bombers of the mid-1930s, and was the last biplane heavy bomber to serve with the RAF.

Design and development

The Heyford was built to Air Ministry specification B.19/27 for a heavy night bomber to replace the Vickers Virginia, competing with the Vickers Type 150 and the Fairey Hendon designs. The prototype, the Handley Page HP.38, was designed by Handley Page's lead designer G R Volkert and first flew on 12 June 1930 at Handley Page's factory at Radlett, Mason, Francis K. "The British Bomber Since 1914". London: Putnam Aeronautical Books, 1994. ISBN 0-85177-861-5.] powered by two 525 hp Rolls-Royce Kestrel II engines driving two-blade propellers.

The aircraft was of mixed construction having fabric-covered metal-frame wings, while the fuselage had an aluminium monocoque forward section with a fabric-covered frame to the rear, with open positions for the pilot and both the nose and dorsal gunners. The Heyford had a novel configuration, with the fuselage attached to the upper wing and the bomb bay in the thickened centre lower wing. This provided a good defensive field of fire for the nose and dorsal guns as well as the ventral retractable "dustbin" turret, each equipped with a single Lewis gun. The fixed undercarriage consisted of large, spat-covered wheels. The design allowed ground crews to attach bomb-loads safely while the engines were running, but the result was that the pilot was some 17 feet off the ground.

The HP.38 proved successful during service trials at Martlesham Heath and with No. 10 Squadron RAF and was chosen as the winner of the B19/27 competition, being ordered as the HP.50 Heyford. Production Heyford Is were fitted with 575 hp Kestrel III engines and retained the two-blade propellers, while the IAs had four-blade propellers. Engine variations marked the main Mk II and III differences; the former being equipped with 640 hp Kestrel IVs, supercharged to 695 hp in the Heyford III.

Operational history

The Heyford I entered service with No. 99 Squadron RAF, at RAF Upper Heyford in November 1933, and later with No. 10 Squadron and 7 Squadron, re-equipping with the Heyford IA and II in August 1934 and April 1935 respectively. As part of the RAF's Expansion scheme, orders were placed for 70 Heyford IIIs in 1936, with steam condenser-cooled Rolls-Royce Kestrel VI engines. The delivery of these aircraft allowed the RAF to have nine operational Heyford Squadrons by the end of 1936.

These squadrons of Heyfords formed the major part of Bomber Command's night bomber strength in the late 1930s. Heyfords flew many long night exercises, sometimes flying mock attacks against targets in France. Disaster struck on one of these long-range exercises on 12 December 1936 when a flight of seven Heyfords of No. 102 Squadron RAF flying from Northern Ireland, encountered fog and icy weather conditions as they approached their base at RAF Finningley, Yorkshire. Four crashed and two had to make forced landings resulting in three crewmen killed and three injured.

The Heyford started to be replaced in 1937 with the arrival in service of Armstrong Whitworth Whitleys and Vickers Wellesleys,Thetford, Owen. "Aircraft of the Royal Air Force 1918-57, 1st edition". London: Putnam, 1957. finally being retired from frontline service in 1939. Some remained flying until 1940 as bombing and gunnery trainers, being declared obsolete in July 1939. Donald, David (ed.) "The Encyclopedia of World Aircraft". London: Aerospace Publishing, 1997. ISBN 1-85605-375-X.] At least two examples found experimental use; one for airborne radar and the other for inflight refuelling, and it is reported that one was still flying as late as 1944.

Variants

;Heyford I :Powered by 575 hp Rolls-Royce Kestrel III engines: 15 built

;Heyford IA:Engine support changes, power-driven generator, four-blade propellers: 23 built

;Heyford II:Powered by 640 hp Kestrel IV engines: 16 built

;Heyford III:Supercharged 695 hp Kestrel VI engines: 70 built

For a total of 125 (including prototype)

Operators

;UK
* Royal Air Force
**No. 7 Squadron RAF
**No. 9 Squadron RAF
**No. 10 Squadron RAF
**No. 16 Squadron RAF
**No. 30 Squadron RAF
**No. 38 Squadron RAF
**No. 58 Squadron RAF
**No. 76 Squadron RAF
**No. 78 Squadron RAF
**No. 97 Squadron RAF
**No. 99 Squadron RAF
**No. 102 Squadron RAF
**No. 148 Squadron RAF
**No. 149 Squadron RAF
**No. 166 Squadron RAF

pecifications (Heyford I)

aircraft specifications
plane or copter?=plane
jet or prop?=prop
ref=British Aircraft Directory [ [http://www.britishaircraft.co.uk/aircraftpage.php?ID=228 British Aircraft Directory] ]
crew=4 (pilot, Navigator/bomb-aimer/forward gunner, wireless operator/mid-upper gunner, rear-gunner
capacity=
payload main=
payload alt=
length main= 58 ft
length alt= 17.68 m
span main= 75 ft
span alt= 22.86 m
height main=17 ft 6 in
height alt= 5.34 m
area main= 1,470 ft²
area alt= 136.6 m²
airfoil=
empty weight main= 9,200 lb
empty weight alt= 4,180 kg
loaded weight main= 16,900 lb
loaded weight alt= 7,680 kg
useful load main=
useful load alt=
max takeoff weight main=
max takeoff weight alt=
more general=
engine (prop)= Rolls-Royce Kestrel III-S (or III-S5)
type of prop=V-12 inline piston engine
number of props=2
power main= 575 hp
power alt= 426 kW
power original=
max speed main= 123 knots
max speed alt= 142 mph, 229 km/h
cruise speed main=
cruise speed alt=
stall speed main=
stall speed alt=
never exceed speed main=
never exceed speed alt=
range main= 800 nm
range alt=920 miles, 1481 km
ceiling main= 21,000 ft
ceiling alt= 6,400 m
climb rate main=
climb rate alt=
loading main= 11.5 lb/ft²
loading alt= 56.2 kg/m²
thrust/weight=
power/mass main= 0.068 hp/lb
power/mass alt= 0.111 kW/kg
more performance=*Climb to 10,000 ft (3,050 m): 15.3 minutes
guns= Three Lewis guns (nose, dorsal and ventral 'dustbin' positions)
Bombs=2,000 lb total
avionics=

ee also

aircontent
related=

similar aircraft=

lists=
*List of aircraft of the RAF
*List of bomber aircraft

see also=

References

;Notes;Bibliography
* Barnes, C. H. "Handley Page Aircraft Since 1907". London: Putnam & Company, Ltd., 1987.
* Clayton, Donald C. "Handley Page, an Aircraft Album". Shepperton, Surrey, UK: Ian Allan Ltd., 1969. ISBN 0-7110-0094-8.
* Moyes, Philip J.R. "The Handley Page Heyford (Aircraft in Profile number 182)". Leatherhead, Surrey, UK: Profile Publications Ltd., 1967.

External links

* [http://www.handleypage.com/Aircraft_hp38_and_hp50.html Handley page Aircraft]