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HP Heyford, specifications and service history

The Heyford originated from the H.P.38 and was first flown in June 1930 by S/Ldr. T. H. England. Built to Air Ministry Specification B. 19/27, it was fitted with two 525-h.p. Rolls-Royce FXIV (Kestrel II) engines driving two-blade propellers of 12 ft. 6 in. diameter. This machine (serial J9130) crashed while on service trials on 8th July 1932.

H.P.50 covered all production versions of the Heyford. The Mk. I was first flown on 21st June 1933, powered by two 600h.p. Kestrel IIIs, still fitted with two-blade propellers. Most Mk. Is were brought up to Mk. IA standard by the end of 1934. The Mk. IA differed in having power generators (instead of the Mk. I's wind-driven type) and four-blade propellers. All were built to Air Ministry Specification B.23/32 and were delivered from 2nd November 1933 to 8th December 1934-(15) Mk. Is K3489-3503, (23) Mk. IAs K4021-4043.

The Mk. II, powered by two 640-h.p. Kestrel VIs, was first flown towards the end of 1934. It was built to Air Ministry Specification B.28/34. Delivered from 27th March 1935 to 26th June 1935-(16) Mk. Its K4863-4878.

The Mk. III was first flown in May 1935 in the guise of K4029, a modified Mk. IA from No. 10 Squadron. Main external differences were the vee-type air intakes and steam condensers which were fitted for the Kestrel VI engines, which were now fully supercharged and developed a maximum of 695 h.p. each. These aircraft were built in two batches to Air Ministry Specification B.27/35-(20) K5180-5199, (50) K6857 6906, all delivered from 22nd August 1935 to 30th July 1936.

Squadrons equipped with the Heyford, and details of their individual aircraft, were as follows:

No. 7 Squadron, Worthy Down and Finningley (April 1935 - March 1938), received Mk. I/IAs K3490-1, Mk. IIs K486378, Mk. IIIs K6873-78. K4871 struck trees on approach to Finningley and was burnt out, 30/3/38; K4876 ditto, 6/4/37.

No. 9 Squadron, Aldergrove, Scampton and Stradishall (March 1936-May 1939), received Mk. IA K4032, Mk. II K4866, Mk. Ills K5182, K5185, K5189-90, K5192, K5194, K6862-3, K6865-70, K6878-9, K6881, K6893, K6902-4, K6906. K4032 struck fence at Mildenhall, 8!9!38; K5190 hit Histhorpe House, Scampton, 1/9/37; K5194 hit trees landing at Stradishall, 4/11/38; K6865 forced landing at Theddlethorpe range, undercarriage collapsed, 5/1/38; K6867 engine failed on take-off, Scampton, 9/8/37.

No. 10 Squadron, Boscombe Down and Dishforth (August 1934-March 1937), received Mk. lAs K4021-35, K4037, K4041, Mk. Ills K5185, K5193-98, K6879. K4024 hit Beacon Hill, near Midhurst, and was burnt out 19/2136; K4035 crashed and burnt out near Boscombe Down, 6/5/36.

No. 38 Squadron, Mildenhall (September 1935-March 1937), received Mk. I/IAs K3493, K3499, K3501, K4039, K4041, K4043, Mk. Ills K6859-60, K6862-4, K6871.

No. 78 Squadron, Boscombe Down and Dishforth (November 1936-March 1938), received Mk. IIs K4866, K4868, K4870, K4872, K4878, Mk. Ills K5193-8, K6862, K6885-6.

No. 97 Squadron, Catfoss, Boscombe Down and Leconfield (September 1935, August 1939), received Mk. I/IAs K34913, K3499, K4022-3, K4026-8, K4030, K4034, K4038, K4040-2, Mk. Its K48689, K4877-8, Mk. IIIs K5184, K5189, K6862-3, K6870, K6872-5. K4034 crashed in sea off Le Havre, 19,/2!36. '

No. 99 Squadron, Upper Heyford and Mildenhall (November 1933-November 1938), received Mk. I/IAs K3490-3502, K4036, K4039-41, K4043, Mk. II K4877, Mk. Ills K5191, K5196-9, K6857-61, K6864, K6871, K6876-7, K6879, K6885, K6893-4, K6896-7, K6903, K6905-6. K3497 crashed at Upper Heyford, 6/7/34; K3500 crashed, engine failure, 21/5/37; K6879 crash-landed in a marsh, 3/1/38.

No. 102 Squadron, Worthy Down, Finningley and Honington (October 1935 May 1939), received Mk. IIs K4864, K4866, K4868, K4870, K4872, K4874, Mk. IIIs K5180-3, K5186-8, K5193, K6859-61, K6878, K6896, K6898-6901. K4864 crashed, Blyborough, hit telegraph pole, 12/12/36; K4868 force-landing in field at Disley, 12/12/36; K4874 crashed and burnt out, Moorside, Oldham, 12/12/36; K5183 crashed near Honington, 16/12/37; K5188 force-landing at Flaxton, 12/12/36; K6860 crashed near Evanton after engine failure, 24/3/38; K6900 crashed and burnt out at Hebden Bridge, 12/12/36; K6898 crashed at Disley, hit telegraph pole, 12/12/36.

No. 148 Squadron, Stradishall (November 1938-March 1939), received Mk. IIIs K5191, K5196-9, K6857, K6864, K6871, K6876, K6885, K6896-7, K6899, K6905.

No. 149 Squadron, Mildenhall (April 1937-March 1939), received Mk. I/IAs K3489, K3494-5, K3502, K4021, K4025, K4031-3, K4037, K4039, K4043, Mk. Its K4865-7, K4870, K4875, K4877-8, Mk. IIIs K5180, K5186-7, K5191, K5199, K6857-9, K6864, K6871, K6876-7, K6893, K6901, K6903-4. K4037 crashed near Stockton after engine failure, 15/2/38; K4039 hit high ground at Stopham, burnt out, 13/12/37; K4021 crashed after engine failure, 30/4/38.

No. 166 Squadron, Boscombe Down and Leconfield (November 1936-September 1939), received Mk. IIIs K3503, K4029 (both converted), K5184, K5195, K6862-3, K6872-5, K6880, K6886-92, K6895. K6875 crashed and burnt out on Kinder Scout, Edale, 22/7/37; K6880 caught fire on start-up and burned out at Empire Air Day Display, Weston-super-Mare, 29/5/37.

No. 3 Bombing and Gunnery School, Aldergrove (May 1939-March 1940), received Mk. IIIs K5182, K5191-2, K5196, K5198-9, K6857, K6864, K6871, K6876, K6885, K6887, K6899, K6904-5.

No. 4 Bombing and Gunnery School, West Freugh (March 1939-July 1940), received Mk. HIS K5185, K5187-8, K5193, K5195, K5197, K6859, K6862, K6866, K6868-70, K6872, K6878, K6883, K6888-9, K6891, K6893, K6896-7, K6906.

HEYFORD SPECIFICATION (Mk. IA): Span 75 ft., length 58 ft., height (tail up) 20 ft. 6 in., height over nose (tail down) 17 ft. 6 in., wing area 1,470 sq. ft.; weight empty 9,2001b., weight loaded 16,9001b.; maximum speed 142 m.p.h., climb 15.3 min. to 10,000 ft., service ceiling 21,000 ft., range 920 miles (with 1,660-lb. bomb load); armament, three Lewis guns in nose, dorsal and ventral positions, plus 1,6602,6601b. of bombs (max. comprised 10 x 250-lb. plus 8 x 20-lb.). D. Thompson, HANDLEY PAGE SPECIALIST.

The previous text was added by 81.86.144.210 on 7 March 2006. Where was this information obtained? It would be nice to have a source. Drutt (talk) 20:57, 3 June 2008 (UTC)[reply]

Please explain steam condensers.

Wasn't the Kestrel cooled with pressurized high temperature water, with little or no phase change? In steam systems a condenser is a heat exchanger where steam turns to water. How can there be a condenser in a pressurized water cooling system? Spamhog (talk) 21:13, 10 July 2014 (UTC)[reply]

I think these systems were employed for a time before the adoption of ethylene glycol-filled pressurised systems which allowed the cooling system to run at temperatures above the boiling point of water. I have a feeling the Kestrel straddled these developments, with early engines using a simple system, later engines the pressurised one. There was also a version of the Kestrel that used steam itself as the coolant, the Rolls-Royce Goshawk, but it was not a success as the introduction of ethylene glycol pressurised systems made its development somewhat redundant.

Early water-cooled systems did not pressurise the system so I assume this is the case here. Later systems were run at above atmospheric pressure, which increased the coolant's boiling point, and hence made the system more efficient, which allowed the use of smaller radiators, which in turn, caused less drag. However I may be wrong. — Preceding unsigned comment added by 95.149.55.42 (talk) 09:29, 10 March 2019 (UTC)[reply]