A.Jackson Avro Aircraft since 1908 (Putnam)
Reference has been made in previous chapters to a unique batch of civil aircraft built in the Hamble works between April and November 1919. To satisfy the enormous demand for pleasure flights, the Avro Transport Company simply had to provide more seats and quickly. The problem was solved by giving some of these Hamble 504K variants a nine inch increase in width to enable four passengers to sit in side by side pairs in the rear cockpit. Each occupant had his own individual windscreen, the rear windscreens being fixed to a strip of decking hinged to the starboard top longeron for ease of entry. In this form, as the Avro 536, the machine was a short range five seater and (as in the case of Avro 504Ls from the same production batch), extra take-off power at the higher all-up weight was given by a 150 h.p. Bentley B.R.I.
The Avro 536 was easily distinguishable from the 504K since the extra nine inches of width resulted in an obvious difference in the spacing of the centre section struts. Sporting a tricolour rudder, but no other markings apart from AVRO in large white letters, the prototype first flew at Hamble in April 1919 one of the first passengers being the Lord Chancellor who flew in it with H. A. Hamersley on the 25th of that month. Eight production 536s which followed plunged immediately into the fray at southern joyriding sites: K-104 to K-106 at Hounslow Heath; K-l 16 and K-l37 at Southsea; K-161 at Weston-super-Mare; and K-166 at Margate. K-165 is believed to be that sent to the First Air Traffic Exhibition at Amsterdam. A batch of 12 was also put in hand at Manchester but only seven of these were certificated in time to earn money in 1919. Whereas the constructor's numbers of the Hamble batch were prefixed A.T.C, (Avro Transport Company), those built in Manchester were initialled B for Blackpool where three pilots carried 500 passengers in 536s on the day of their introduction.
All Avro 536s had the 504L-type fin to offset the torque of the powerful Bentley rotary except the first three production aircraft, two of which were involved in serious accidents. Capt. H. R. Hastings was killed when K-106 stalled on approaching to land at Sandhurst at the end of a charter flight from Hounslow on August 8, 1919; and Capt. E. A. Sullock, on direct track from Hounslow to Southend with two passengers on September 9, suffered engine failure over Rotherhithe and put K-104 down in Southwark Park where it broke its back. A third Avro pilot, Brig. Gen. C. F. Lee C.M.G., who had demonstrated the 504J C4312 at Washington in 1917, was killed when the fin-equipped K-161 stalled when coming in to land on Weston-super-Mare sands in the same month.
Unlike other Avro 536s, the prototype boasted a large aerofoil shaped centre section fuel tank and after a few trial flights at Hamble, was fitted with floats and extended fin to become the sole 536 seaplane. It retained the tricolour rudder and on July 2, 1919 commenced a joyriding season in the Isle of Wight as K-114. The pilot was Capt. F. Warren Merriam who flew A. V. Roe daily to and from Hamble while he was on holiday in the island and, assisted by a 504L, completed a two months' lucrative season at Ryde, Sandown, Shanklin and Ventnor. The last two Hamble-built 536s were special aircraft; K-139 / G-EADV was a two seater with large fuselage fuel tank for experimental work or long distance competition flying, and the other (23rd and last machine on the mixed production line) was converted into a cabin type known as the Avro 546 for three passengers and pilot. Main differences between this aircraft and the contemporary Avro 504M lay in the widened fuselage, open pilot's cockpit, squarish windows below the top longeron and the Bentley B.R.I engine. Registered G-EAOM, the Avro 546 saw little service and only made a few flights at Hamble and West Blatchington Farm, Brighton, early in 1919-20.
When the Avro Transport Company ceased operations a few of its former pilots hired 536s and carried on in 1920 but all eventually returned to Alexandra Park for storage. Four from the tail end of the production line (G-EAKM-'KP), completed too late to be used commercially, were also stored. In 1923 F. J. V. Holmes bought 'KN for use by Berkshire Aviation Tours Ltd. and in 1925 'KJ, 'KM and 'KP were acquired by Surrey Flying Services Ltd. to take over joyriding from their aged 504Ks.
Bentley rotaries were no longer in service in 1925 and the Surrey Avro 536s were fitted with Clcrgets. With reduced fuel loads they were very economical indeed, carrying pilot and four passengers quite satisfactorily on the company's famous 5 minute/5 shilling 'flips'. Low power also made the dorsal fin unnecessary and in 1926-27 the firm erected four additional Avro 536s G-EBOF, 'OF, 'RB and 'TF, for which no original construction details were recorded. They were evidently the best of the other airframes still remaining at Alexandra Park (then in process of closing down) and the unexplained constructor's number P.8 given for G-EBOY was evidently a corruption of B.8, identifying it as the former G-EAKL. They seldom ventured far afield, although G-EBOY gave joy flights from the beach at Jersey in 1927 and during a barnstorming tour in 1928 'RB was used extensively for wing walking exhibitions.
SPECIFICATION AND DATA
Manufacturers: A. V. Roe and Co. Ltd., Newton Heath, Manchester; and Hamble Aerodrome, near Southampton, Hants.
One 130 h.p. Clerget
One 150 h.p. Bentley B.R.I
One 150 h.p. Bentley B.R.I
Span 36 ft. 9 in.
Length 29 ft. 5 in.
Height 10 ft. 5 in.
Wing area 335 sq. ft.
Tare weight 1,431 lb.
All-up weight 2,226 lb.
Maximum speed 90 m.p.h.
Cruising speed 70 m.p.h.
Initial climb 550 ft./min.
Ceiling 12,000 ft. Range 190 miles
Note: The above figures apply to both Avro 536 and 546.
(a) Hamble built
K-114 / G-EACC, c/n A.T.C.l, C. of A. 3.7.19, prototype flown as landplane 5.19 and as seaplane 7.19, s.o.r. 7.21
A.T.C.2-A.T.C.9: K-104/G-EAAQ, C. of A. 14.5.19, crashed in South-wark Park, London 9.9.19; K-105/G-EAAP, C. of A. 14.5.19, crashed 12.19; K-106/G-EAAO, C. of A. 16.5.19, crashed at Sandhurst 6.8.19; K-137/ ' G-EADC, C. of A. 3.6.19, scrapped at Hamble 12.19; K-161/G-EAGM, C. of A. 12.7.19, crashed at Weston-super-Mare 1.9.19; K-165/G-EAHA, C. of A. 12.8.19, s.o.r. 9.20, believed in the Netherlands; K-166JG-EAHB, C. of A. 17.7.19, scrapped at Hamble 12.19; K-J16/G-EACG, C. of A. 17.6.19, crashed 12.19.
A.T.C.11, K-139/G-EADV, experimental long range two seater, scrapped 12.19; A.T.C.23, G-EAOM, C. of A. 22.12.19, completed as Avro 546, s.o.r. 12.20
(b) Manchester built
c/n B.1-B.12: K-173/G-EAID, K-174JG-EAIE (Fleet No. 19), G-EAKD, K-175JG-EAIF and G-EAJR, all certificated 8.19, placed in storage at Alexandra Park 8.21; G-EAKJ, C. of A. 9.9.19, based at Brighton, to Surrey Flying Services Ltd. 4.24; G-EAKK, C. of A. 9.9.19 and G-EAKL, C. of A. 19.11.19, both stored at Alexandra Park 8.21; G-EAKM to Surrey Flying Services, C. of A. 18.8.25, crashed at Taplow, Bucks. 6.7.28; G-EAKN to F. J. V. Holmes, C. of A. 17.4.24, crashed 1.9.24; G-EAKO stored at Alexandra Park 8.21; G-EAKP to Surrey Flying Services Ltd., C. of A. 15.7.25
(c) Erected by Surrey Flying Services Ltd., Croydon
G-EBOF, C. of A. 26.6.26; G-EBOY, C. of A. 28.8.26; G-EBRB, C. of A. 13.5.27, crashed 12.6.28; G-EBTF, C. of A. 1.9.27. Surviving three s.o.r. 12.30
A.Jackson British Civil Aircraft since 1919 vol.1 (Putnam)
During its civil career a number of major variants of the Avro 504K appeared. First came the float-equipped 504L, 10 of which augmented the Avro fleet at seaside resorts and on Lake Windermere. Howard Pixton, manager of the Windermere floatplanes, flew a regular and successful newspaper service to the Isle of Man during the summer of 1919. Five others were flown on the south coast that season by the Eastbourne Aviation Go. Ltd. The Avro Company persuaded four passengers into the rear cockpit of some land machines by increasing the width of the fuselage by 9 in. to create a variant known as the Avro 536. A prototype, K-104, and 20 ‘production’ conversions were made at Woodford in 1919, while four others - G-EBOF, ’OY, ’RB and ’TF - were converted by Surrey Flying Services Ltd. in 1926-27. This firm, founded at Croydon by A. F. Muir and W. J. Grant with two Avro 504Ks, G-EAWI and ’WJ, in 1919, carried thousands of passengers in its famous blue machines until the last of the large fleet, G-AAGB, was written off in 1934. The manufacturers also produced two cabin versions, the first of which was fitted with a 100-h.p. Gnome and designated 504M. This aircraft, K-134, later G-EACX, seated two behind the pilot in a cabin provided with portholes above the top longerons and did a great deal of pleasure-flying from Hounslow Heath in 1919-20. Taking off from a grass strip outside Chorley Wood Church in June 1919, it took a newly married couple to Fowey, Cornwall, on what was probably the first post-war British internal charter. The other cabin version, the Avro 546, was a three-seater converted from an Avro 536 G-EAOM in October 1919. The Triplex windows were below the top longeron on this variant, and a 150-h.p. Bentley B.R.1 was fitted. Only one Avro 546 was produced, and only two other variants are worthy of note. First was the Avro Company’s experimental machine G-EAPR, which in October 1919 had 504K wings and a 90-h.p. Curtiss OX-5 engine. In this form it was designated the Avro 545. The other was an Avro 504K G-EAGI, locally modified at Northolt with a long-legged V strut, skidless undercarriage for use with seven other standard machines at the Central Aircraft Company’s flying-school.
Dimensions: Length, 29 ft. 5 in. Height, 10 ft. 5 in.
Avro 504K and 504M Avro 504L Avro 536 and 546
Span 36 ft. 36 ft. 36 ft. 9 in.
Wing area 330 sq. ft. 330 sq. ft. 335 sq. ft.
Tare weight 1,231 lb. 1,408 lb. 1,431 lb.
All-up weight 1,829 lb. 2,006 lb. 2,226 lb.
Maximum speed 95 m.p.h. 80 m.p.h. 90 m.p.h.
Cruising speed 75 m.p.h. 65 m.p.h. 70 m.p.h.
Initial climb 700 ft./min. 600 ft./min. 550 ft./min.
Ceiling 16,000 ft. 15,000 ft. 12,000 ft.
Range 225 miles 160 miles 200 miles