Handley Page H.P.54 Harrow

{{Short description|World War II British heavy bomber aircraft}} {{About|the twin-engine high-wing monoplane|the single-engine biplane|Handley Page H.P.31 Harrow}} {{Use dmy dates|date=June 2015}} {{Use British English|date=May 2026}}  {{Infobox aircraft |name= H.P.54 Harrow |image= File:HP Harrow ExCC.jpg |caption= Harrow of [[No. 115 Squadron RAF|No. 115 Squadron]] |type= Heavy bomber |manufacturer= [[Handley Page]] |designer= [[Gustav Lachmann|G. V. Lachmann]] |first_flight= 10 October 1936 |introduction= 1937 |retired= 1945 |status= |primary_user= [[Royal Air Force]] |more_users= [[Royal Navy]] <br /> [[Royal Canadian Air Force]] |produced= 1936–1937 |number_built= 100 |developed_from= [[Handley Page H.P.51]] }}

The '''Handley Page H.P.54 Harrow''' was a [[heavy bomber]] designed and produced by the British aircraft manufacturer [[Handley Page]]. It was operated by the [[Royal Air Force]] (RAF) and used during the [[Second World War]], although not as a bomber.

The Harrow was developed during the 1930s as a derivative of the [[Handley Page H.P.51]], an unsuccessful [[monoplane]] bomber-transport hybrid. It was a twin-engine, high-wing monoplane with a fixed [[Landing gear|undercarriage]]. In 1935, the [[Air Ministry]] wrote [[List of Air Ministry Specifications#1930-1939|Specification B.29/35]] around the Harrow proposal, seeking a 'stop-gap' heavy bomber to facilitate the expansion of the RAF's bomber squadrons. Handley Page updated the design with new features and along with structural changes to enable more rapid construction. Despite incorporating several modern features, including [[hydraulically]]-powered turrets, [[steam boiler|steam]]-based cabin heating, and [[variable-pitch propeller (aeronautics)|variable-pitch propeller]]s, the performance of the Harrow did not match that of contemporary bombers such as the [[Armstrong Whitworth Whitley]].

On 14 August 1936, the Air Ministry ordered one hundred Harrows for the RAF. While the [[Fleet Air Arm]] also placed a separate order for one hundred Harrows, Handley Page did not have the capacity to produce these aircraft. On 13 January 1937, the first Harrow was delivered to [[No. 214 Squadron RAF|No. 214 Squadron]]; by the end of that same year, all one hundred of the RAF-bound units had been delivered. By the end of 1939, the Harrow had been rapidly displaced as a frontline bomber, it was flown as a transport aircraft instead, which included its use as an [[air ambulance]]. It participated in several major actions, including an unorthodox defensive role for [[The Blitz]] in the winter of 1940–1941 and [[Operation Market Garden]] in September 1944. Limited numbers served through to the conclusion of the conflict, the RAF withdrew the Harrow in May 1945.

==Development== ===Background=== The H.P. 54 Harrow was the production version of the earlier [[Handley Page H.P.51]] design, itself a monoplane conversion of the three-engined [[Handley Page H.P.43]] biplane.<ref name="Barnes1">Barnes 1987, pp. 347–351.</ref> The two monoplanes were designed by Dr. [[Gustav Lachmann]]. The aviation author C. H. Barnes observes that, despite rumours to the contrary, the development of the Harrow had nothing to do with [[Air Ministry]] [[List of Air Ministry Specifications#1920-1929|Specification B.9/32]], for a specialist [[medium bomber]]; several features of the aircraft, such as its fixed [[landing gear|undercarriage]] and general construction, were incompatible with the requirements laid out.<ref name="barnesp372"/> Instead, the aircraft had been developed for the Specification C.26/31, which sought a new bomber-transport aircraft. Handley Page had intended to offer the preceding H.P.51, before opting for the H.P.54 at the last minute as it was viewed as a superior offering to fulfil the requirement.<ref name="barnesp372">Barnes 1976, p. 372.</ref>

Recognising that production of existing bombers, such as the [[Armstrong Whitworth Whitley]], or upcoming projects be reasonably accelerated, the Air Ministry came to recognise that additional types of aircraft would have to be procured if it was to keep pace with political pressures to equip the [[Royal Air Force]], which was undergoing a period of rapid expansion and modernisation, including the growth of its bomber force, as the situation in Europe deteriorated.<ref name="barnesp372"/> In June 1935, [[List of Air Ministry Specifications#1930-1939|Specification B.29/35]] was written around the Harrow as a 'stop-gap'; it was directed to be suitable for rapid production despite its performance not being equal to front-line peers. The use of the aircraft as bomber was emphasised by B.29/35 over that of its transport capability, although this was retained as a secondary role.<ref name="barnesp3723">Barnes 1976, pp. 372-373.</ref>

To fulfil the specification, which sought the Harrow as a heavy bomber, the design had to be reworked, largely in terms of its structure.<ref name="barnesp3723"/> Several new features were introduced, including [[variable-pitch propeller (aeronautics)|variable-pitch propeller]]s, [[steam boiler]]s to heat the cabin and [[hydraulically]]-powered turrets. Modern construction methods drawn from studies of American [[automotive]] factories were adopted, which included a sub-assembly flow system and priority being placed on a high standard of practical training.<ref name="barnesp373">Barnes 1976, p. 373.</ref> On 14 August 1936, months before the first Harrow flew, the Air Ministry opted to place a production order for one hundred aircraft.<ref name="Barnes2">Barnes 1987, p. 372.</ref> The [[Fleet Air Arm]] also placed its own order for another hundred but Handley Page found that it lacked the production capacity to supply them.<ref name="lewis bomber"/> Quantity production of the Harrow commenced shortly after production of the [[Handley Page Heyford]] biplane came to an end.<ref name="barnesp374">Barnes 1976, p. 374.</ref>

===Into flight=== On 10 October 1936, the first Harrow performed the type's [[maiden flight]] from [[Radlett]].<ref name="lewis bomber"/> Service trials of the type commenced at [[RAF Martlesham Heath]] twenty days later using this same aircraft. During January 1937, the second Harrow, which differed from the first by its fitting of the improved [[Bristol Pegasus XX]] [[radial engine]], along with prototype Habbart-F.N. turrets, arrived for armament trials.<ref name="barnesp374"/> In March 1937, following the forced landings of seven Heyfords in bad weather, it was ordered that improved navigator positions be adopted on all bombers wherever feasible, leading to urgent modifications being performed on all Harrows. To speed deliveries, and to allow time to get the hydraulically powered turrets working properly, early production units were delivered to training squadrons without their turrets.<ref name="barnesp374"/>

The Harrow was typically furnished with several [[Gun turret#Aircraft|defensive guns]], including a powered nose and tail turrets as well as a manually operated dorsal turret.<ref name="barnesp373"/> These positions had fixed cupolas that had the guns traverse on a slot; the hydraulic controls were linked with the [[gun sight]], while the weight of the guns was balanced by the gunner. Bomb-airming was performed using the nose turret, which incorporated a flat optical panel.<ref name="barnesp3734">Barnes 1976, pp. 373-374.</ref> Early on, the nose and dorsal turrets were each armed with a [[Lewis gun]], while the tail turret had two. In later service, these guns were typically replaced by [[Vickers K machine gun]]s. The Harrow could carry a maximum bomb load of {{convert|3000|lb|kg|abbr=on}}, which was stowed in a bay directly underneath the floor of the cabin; it was also capable of carrying a {{convert|2000|lb|kg|abbr=on}} bomb.<ref name="am186 p4-7">Lumsden and Heffernan ''Aeroplane Monthly'' January 1986, pp. 4–7.</ref> The majority of Harrows were powered by a pair of Bristol Pegasus XX radial engines, capable of producing up to {{convert|925|hp|kW|abbr=on}}.<ref name="lewis bomber"/>

==Operational history== On 13 January 1937, the first Harrow was delivered to [[No. 214 Squadron RAF|214 Squadron]] at [[RAF Scampton]].<ref name="barnesp374"/> Early examples, powered by the [[Bristol Pegasus X]] engine, were called Harrow Mk.I, while those powered by the more powerful Pegasus XX engine were named Harrow Mk.II. By the end of 1937, all one hundred aircraft had been delivered to a total of five RAF bomber squadrons.<ref name="lewis bomber"/><ref name="barnesp3745">Barnes 1976, pp. 374-375.</ref> Despite the presence of cabin heating, which used the exhaust head of onboard steam boilers, the Harrow gained a reputation amongst air crews of being a cold and draughty aircraft, which was largely attributed to the design of its turrets.<ref name ="mason bomber">Mason 1994, pp. 301–302.</ref>

Two of No. 214 Squadron's new Harrows from [[RAF Feltwell]] collided in mid-air over [[Wissington, Norfolk]] and crashed with the loss of five airmen on 29 April 1937. It was reported that a wing-tip of one aircraft contacted the tail of the other, one falling into a field and bursting into flames, and the other crashing into the [[River Wissey]].<ref>{{cite news |title=Five Men killed in Feltwell R.A.F. Tragedy |url=https://www.britishnewspaperarchive.co.uk/viewer/bl/0002879/19370430/259/0009 |access-date=15 April 2023 |work=Lynn Advertiser |issue=4081, Vol.XCVI |date=30 April 1937 |location=King's Lynn |page=9|via=British Newspaper Archive}}</ref>

[[File:Handley Page Harrow - Royal Air Force Transport Command, 1943-1945. CH11523.jpg|thumb|Interior of an Harrow with [[air ambulance]] fittings installed {{circa| 1943}}.]] As the delivery of more modern bombers, such as the [[Vickers Wellington]] proceeded, the Harrow was withdrawn from front line bomber squadrons by the end of 1939, having never performed any combat missions in this capacity. Perhaps its most prominent use during this brief period was a series of public formation flights performed over various British cities to mark [[Empire Air Day]] in May 1938; the Harrow was also put on stand-by during the [[Munich Crisis]] of 1938.<ref name="barnesp375">Barnes 1976, p. 375.</ref>

Although relegated as a night bomber, the Harrow operated throughout the Second World War as a transport and trainer.<ref name="barnesp3789">Barnes 1976, pp. 378-379.</ref> On 1 May 1940, [[No. 271 Squadron RAF|271 Squadron]] was formed with a mixture of Harrows, [[Bristol Bombay]]s and an assortment of [[impressment|impressed]] civil aircraft.<ref name= "thetford raf">Thetford 1957, pp. 248–249.</ref> While the other aircraft equipping 271 Squadron were replaced by [[C-47 Skytrain|Douglas Dakotas]], it retained a flight of Harrows (sometimes nicknamed "Sparrows" due to their new nose fairings to give a more streamlined fuselage) as transports and ambulance aircraft until [[VE Day]].<ref name="mason bomber"/><ref name="thetford raf2"/>

As a transport, the Harrow was routinely used to convey equipment and personnel between domestic military bases across Britain, as well as to continental airfields prior to the [[Fall of France]].<ref name="barnesp378">Barnes 1976, p. 378.</ref> It also occasionally undertook risky flights between England and [[Gibraltar]]; two aircraft were recorded as having been lost on this route.<ref name="mason bomber"/> Harrows also operated in support of Allied forces in their advance into north-west Europe, evacuating wounded from the [[Operation Market Garden|Arnhem operation]] during September 1944.<ref name="thetford raf"/><ref name="mondey">Mondey 1994, pp. 125–126.</ref> Seven Harrows were destroyed by a low level attack by ''[[Luftwaffe]]'' fighters of [[JG 26]] and [[JG 54]] on [[Haren Airport|Evere]] airfield as part of [[Unternehmen Bodenplatte]], the German attack on Allied airfields in north-west Europe, on 1 January 1945, leaving only five Harrows intact. These were retired on 25 May 1945.<ref name="mason bomber"/><ref name="mondey"/>

The Harrow also served in a novel operational role at the height of [[The Blitz]] against Britain in the winter of 1940–1941. Six Harrows equipped [[No. 420 Flight RAF|420 Flight]] (later [[No. 93 Squadron RAF|93 Squadron]]) which used lone Harrows to tow Long Aerial Mines (LAM) into the path of German bombers.<ref name="mondey"/><ref name="barnesp379">Barnes 1976, p. 379.</ref> The LAM had an explosive charge on the end of a long cable and the unorthodox tactic was credited with the destruction of between four and six German bombers.<ref name="mason bomber"/><ref name="mondey"/> The experiment was judged of poor value and the planned deployment of [[Douglas Havoc]]s in the LAM role was cancelled.<ref>Price 1978, pp. 152–153</ref> Seven Harrows were also used by [[782 Naval Air Squadron]] of the Fleet Air Arm as transports from June 1941 to July 1943, being used to carry engines and spare parts as well as passengers.<ref name="sqdp104-5">Sturtivant and Ballance 1994, pp. 104–105</ref><ref>Sturtivant and Burrow 1995, p. 292</ref>

The Harrow was trialled as an aerial tanker for [[aerial refuelling]] of [[Imperial Airways]] [[Short Empire]] [[flying boat]]s, to enable them to cross the Atlantic with a useful payload. Three Harrows were modified by [[Flight Refuelling Limited]], with two Harrows stationed at [[Gander, Newfoundland]] and the third based at [[Foynes, Ireland]]. Meanwhile four Empire flying boats were equipped to receive fuel by this method, and between August and September 1939, 15 trans-Atlantic crossings were made using this system. The trials came to an end with the outbreak of World War II, and the two Harrows based at Gander were pressed into service with the [[Royal Canadian Air Force]].<ref name="barnesp376">Barnes 1976, p. 376.</ref><ref>{{cite journal |last1=Cobham |first1=Sir Alan |title=Refuelling in flight - A lecture to the Royal Aeronautical Society |journal=Flight |date=April 25, 1940 |page=383 |url=http://www.flightglobal.com/pdfarchive/view/1940/1940%20-%201219.html?search=Flight%20Refuelling |access-date=1 October 2024 |archive-date=5 October 2013 |archive-url=https://web.archive.org/web/20131005122815/http://www.flightglobal.com/pdfarchive/view/1940/1940%20-%201219.html?search=Flight%20Refuelling |url-status=bot: unknown }}</ref>

==Variants== ;Harrow Mk.I :Powered by two 830 hp (620 kW) [[Bristol Pegasus X]] engines, 19 built. ;Harrow Mk.II :Powered by two 925 hp (690 kW) Pegasus XX engines, 81 built.

==Operators== [[File:Handley Page Harrow - Feltwell - The Royal Air Force in the 1930s HU67364.jpg|thumb|Harrows of No. 214 Squadron at [[RAF Feltwell]], circa 1938]] [[File:Handley Page Harrow - Royal Air Force Transport Command, 1943-1945. CH11522.jpg|thumb|Medical orderlies loading stretcher cases into a Harrow air ambulance of No. 271 Squadron at RAF Hendon, Middlesex, circa 1943]] ;{{flag|Canada|1921}} * [[Royal Canadian Air Force]] ;{{UK}} * [[Royal Air Force]] ** [[No. 37 Squadron RAF|No. 37 Squadron]] – 1937–1939 at [[RAF Feltwell]]<ref name="jefford37"/> ** [[No. 75 Squadron RAF|No. 75 Squadron]] – 1937–1939 at [[RAF Driffield]] and later [[RAF Honington]]<ref>Jefford 1988, p. 48.</ref> ** [[No. 93 Squadron RAF|No. 93 Squadron]] – 1940–1941 at [[RAF Middle Wallop]] (aerial mine role)<ref name="jefford37">Jefford 1988, p. 37.</ref> ** [[No. 115 Squadron RAF|No. 115 Squadron]] – 1937–1939 at [[RAF Marham]]<ref>Jefford 1988, p. 52.</ref> ** [[No. 214 Squadron RAF|No. 214 Squadron]] – 1937–1939 at [[RAF Scampton]] later RAF Feltwell<ref name="jefford71">Jefford 1988, p. 71.</ref> ** [[No. 215 Squadron RAF|No. 215 Squadron]] – 1937–1939 at RAF Driffield and later RAF Honington<ref name="jefford71" /> ** [[No. 271 Squadron RAF|No. 271 Squadron]] – 1940–1945 at [[RAF Doncaster]] later [[RAF Down Ampney]] (transport role)<ref name="jefford82">Jefford 1988, p. 82.</ref> ** [[No. 420 Flight RAF|No. 420 Flight]] – became 93 Squadron<ref name="jefford37" /> ** [[No. 1680 Flight RAF|No. 1680 Flight]] – became 271 Squadron<ref name="jefford82" /> * [[Fleet Air Arm]] ** [[782 Naval Air Squadron]]<ref name="sqdp104-5"/> * [[Flight Refuelling Limited]]

==Specifications (Harrow II)== [[File:Handley Page Harrow 3-view L'Aerophile August 1937.jpg|thumb|Handley Page Harrow 3-view drawing from L'Aerophile August 1937]] {{Aircraft specs |ref= ''The British Bomber since 1914''<ref name="lewis bomber">Lewis 1980, pp. 270–271.</ref> |prime units?=imp  |crew= 5 |capacity= 20 fully equipped soldiers<ref name="thetford raf2">Thetford 1957, p. 499.</ref> or 12 stretcher cases (used as transport) |length ft= 82 |length in= 2 |length note= |span ft= 88 |span in= 5 |span note= |height ft= 19 |height in= 5 |height note= |wing area sqft= 1,090 |wing area note= |aspect ratio= |airfoil= |empty weight lb= 13,600 |empty weight note= |gross weight lb= 23,000 |gross weight note= |max takeoff weight lb= |max takeoff weight note= |fuel capacity= |more general=  |eng1 number= 2 |eng1 name= [[Bristol Pegasus XX]] |eng1 type= nine-cylinder air-cooled radial piston engines |eng1 hp= 925 |eng1 note= for take-off

|prop blade number= 3 |prop name= variable-pitch propellers |prop dia ft= |prop dia in= |prop dia note=  |max speed mph= 200 |max speed note= |cruise speed mph= 163 |cruise speed note= |stall speed mph= |stall speed note= |never exceed speed mph= |never exceed speed note= |minimum control speed mph= |minimum control speed note= |range miles= 1,260 |range note= |combat range miles= |combat range note= |ferry range miles= |ferry range note= |endurance= |ceiling ft= 22,800 |ceiling note= |climb rate ftmin= 710 |climb rate note= |time to altitude= |lift to drag= |wing loading lb/sqft= 21.1 |wing loading note= |fuel consumption lb/mi= |power/mass= {{cvt|0.0804|hp/lb}} |more performance=  |guns= 4 × 0.303 in (7.7 mm) [[Lewis Gun]]s |bombs= Up to 3,000 lb (1,400 kg) of bombs internally. }}

==See also== {{aircontent  |related= |similar aircraft= * [[Armstrong Whitworth Whitley]] * [[Bristol Bombay]] * [[Dornier Do 23]] * [[Junkers Ju 52]] |lists= * [[List of aircraft of World War II]] * [[List of aircraft of the Royal Air Force]] |see also= * [[Douglas A-20 Havoc|Havoc Mk I (Pandora) intruder]] – also used for Long Aerial Mine (LAM) operations }}

==References==

===Citations=== {{reflist}}

===Bibliography=== * {{cite book |last=Barnes |first=C. H. |title=Handley Page Aircraft Since 1907 |location=London, UK |publisher=Putnam |year=1976 |isbn=0-370-00030-7}} * {{cite book |last=Barnes |first=C. H. |title=Handley Page Aircraft Since 1907 |location=London, UK |publisher=Putnam Publishing |year=1987 |isbn=0-85177-803-8}} * {{cite book |last=Clayton |first=Donald C. |title=Handley Page: An Aircraft Album |location=Shepperton, Surrey, UK |publisher=Ian Allan Ltd. |year=1969 |isbn=0-7110-0094-8}} * {{cite journal |last1=Gardner |first1=Brian |title=Fill 'er Up!: Flight Refuelling Ltd's Handley Page Harrow Experiments, 1938–1940 |journal=The Aviation Historian |date=2018 |issue=25 |pages=64–74 |issn=2051-1930}} * {{cite magazine |last=Gardner |first=Brian|title=Flight Refuelling... The Wartime Story |magazine=[[Air Enthusiast]] |date=1984 |issue=25 |pages=34–43, 80 |issn=0143-5450}} * {{cite book |last=Jefford |first=C. G. |title=RAF Squadrons |edition=1st |location=UK |publisher=Airlife Publishing |year=1988 |isbn=1-85310-053-6}} * {{cite book |last=Lewis |first=Peter |title=The British Bomber Since 1914 |location=London, UK |publisher=Putnam Aeronautical Books |year=1980 |isbn=0-370-30265-6}} * {{cite magazine |last=Lumsden |first=Alec |last2=Heffernan |first2=Terry |title=Probe Probare No. 20: Handley Page Harrow |magazine=Aeroplane Monthly |volume=14 |issue=1 |date=January 1986 |pages=4–7 |issn=0143-7240}} * {{cite book |last=Mason |first=Francis K. |title=The British Bomber Since 1914 |location=London, UK |publisher=Putnam Aeronautical Books |year=1994 |isbn=0-85177-861-5}} * {{cite book |last=Mondey |first=David |title=The Hamlyn Concise Guide to British Aircraft of World War II |location=London, UK |publisher=Aerospace Publishing |year=1994 |isbn=1-85152-668-4}} * {{cite magazine |last=Price |first=Alfred |title=The Long Aerial Mine: Failure or Unrealised Potential? |magazine=Air Enthusiast |issue=6 |date=March–June 1978 |pages=151–153}} * {{cite book |last=Sturtivant |first=Ray |last2=Ballance |first2=Theo |title=The Squadrons of the Fleet Air Arm |location=Tonbridge, Kent, UK |publisher=Air‑Britain (Historians) Ltd. |year=1994 |isbn=0-85130-223-8}} * {{cite book |last=Sturtivant |first=Ray |last2=Burrow |first2=Mick |title=Fleet Air Arm Aircraft 1939 to 1945 |location=Tunbridge Wells, Kent, UK |publisher=Air‑Britain (Historians) Ltd. |year=1995 |isbn=0-85130-232-7}} * {{cite book |last=Thetford |first=Owen |title=Aircraft of the Royal Air Force 1918–57 |location=London, UK |publisher=Putnam Aeronautical Books |year=1957 |oclc=3875235}}

==External links== {{Commons category|Handley Page H.P.54 Harrow}} * [https://web.archive.org/web/20070611172300/http://www.raf.mod.uk/bombercommand/bc_aircraft2.html Bomber Command Aircraft]

[[Category:1930s British bomber aircraft]] [[Category:Handley Page aircraft|H.P.054 Harrow]] [[Category:High-wing aircraft]] [[Category:Aircraft first flown in 1936]] [[Category:Twin piston-engined tractor aircraft]]