In 1917-18, a two-seat reconnaissance aircraft was developed for naval use, which successfully operated from one of the first aircraft carriers and saw service in a combat zone. Ninety-five years later, the Grain Griffin is almost completely unknown, eclipsed by types that never saw action.

© David Bull

The Grain Griffin (sometimes referred to as the Griffon) was developed at the Isle of Grain in Medway, by the Naval Aircraft Experimental Constructive Depot, later part of the Marine Aircraft Experimental Establishment. The Experimental Depot had developed a series of experimental marine aircraft since 1916, but little official support seems to have been given to the Depot’s work and none of the aircraft had gone beyond the prototype stage.

The Depot’s first design, the P.V.1 (for ‘Port Victoria’), was actually a modification of the Sopwith Baby, which substituted the conventional wing section for wings of a highly-cambered ‘high lift’ design. The last, and most successful, was also a development of a Sopwith design, in this case the Hispano-Suiza powered B.1 bomber.

The first Sopwith B.1, before its modification as the prototype Grain Griffin

Sopwith had developed the B.1 not for British services, but as a replacement for the French single-seat version of the 1 ½ Strutter. However, the French rejected the B.1 and the first prototype was offered to the Royal Naval Air Service (RNAS) instead. The aircraft, N50, took part in several bombing raids alongside RNAS DH4s, but although the RNAS praised the B.1’s speed and rate of climb, they found it unsuitable as a bomber because of its single-seat layout.

Undeterred, the RNAS passed N50 to the Experimental Depot at the Isle of Grain to modify the aircraft as a ship-based reconnaissance aircraft with folding wings, radio apparatus and a second crew position.

N50 as modified with shortened, folding wings, a second cockpit and radio. A hydrovane to assist ditching at sea is fitted to the undercarriage

The Depot found that N50 was in many respects unsuitable for this conversion, despite its promising performance. The interplane struts were in exactly the right position to foul the tail-planes with the wings folded back, so the span had to be shortened. The construction of the wings did not allow them to simply be hinged at the rear spar, so a complex arrangement involving the trailing edge folding upwards (top wing) and downwards (lower wing) was implemented. Although previous tests had suggested lateral control was heavy, the conversion required the shortening of the ailerons, which could only have made the problems worse. A hydrovane was fitted to the undercarriage and floatation bags installed.

N50’s conversion was completed, but the results were bound to be unsatisfactory. As a result, the Grain drawing office was given permission to develop a new wing. Flights of the initially-modified N50 proved the wisdom of this, as the aircraft suffered reduced performance and control.

The new wing allowed a better solution for folding, and increased the span to 42’6” over the original Sopwith’s span of 40’6”. A wheel for lateral control replaced the stick of the original, and the Depot reported that handling and performance were greatly restored. The Depot’s drawing office had also prepared designs for a revised fuselage, enlarged to help fit the required radio equipment and a cockpit for the observer in place of the Sopwith’s internal bomb bay. A defensive Lewis gun could be fitted. The aircraft was fitted with a variety of engines, including a Bentley BR1 and a ‘200hp Adder’ engine (possibly an error for Arab or Wolseley Viper) – possibly serving as a prototype for the short series of new-build Griffins. N50 was dispatched to the Mediterranean at the end of 1918, where it disappears from the record.

An order for six aircraft to the new design was placed, numbered N100-106 (within the RNAS series of experimental serials). Instead of N50’s Hispano-Suiza, the production aircraft received either a 200hp Sunbeam Arab or a 230hp Bentley BR2.

The first true Grain Griffin, N100, showing the rather ugly Sunbeam Arab installation and larger, balanced rudder. The similarity to the Sopwith is apparent nonetheless

The first true Griffin, N100, was completed in March 1918 and proceeded to Martlesham Heath for performance testing. The trials gave figures of 115 mph at 5,000 ft, 3 hours’ endurance and a service ceiling of 19,000 ft. The Griffin could climb to 10,000ft in 12 minutes. N100 returned to Grain the following month for modifications, and in September left for service aboard HMS Vindictive.

Vindictive was a light cruiser that had been modified as an aircraft carrier. In 1918 she had a similar layout to one of HMS Furious’ interim stages, with a launching platform on the bow and a landing-on deck on the stern. On 14 November 1918, N100 is recorded as having flown off Vindictive in the Scapa Flow area and returned. At some stage though, the Griffin crashed on deck and was written off. The second Griffin, N101, also went to Vindictive in late November 1918, possibly for deck trials, and embarked again in December, remaining until the end of January 1919.

Grain Griffin N101, showing the much neater Bentley BR2 rotary installation. This aircraft was originally fitted with an Arab, but was later converted to BR2 power

N102 was destined for the Vindictive Flight as well, but swung on take-off when leaving Grain in September 1918, and crashed resulting in the death of Lt Lewis and injury to 2nd Lt Durrance.

N103 and N104 both went to Vindictive in December 1918, while N105 went there some time in 1919. By July, the carrier was in the Baltic supporting the White Russians in the Civil War. During this phase, the Griffins acted as reconnaissance aircraft. In one operation, on 13 August, N105 took off escorted by a Sopwith Camel flown by a Lt Taylor. Shortly after take off, both aircraft suffered engine failure and ditched in the sea. N105 suffered no ill-effects, being recovered by the tug St Ann, neither did her crew. However, Taylor died of a fractured skull. The British personnel suspected sabotage, but water having found its way into the petrol is equally likely.

The last Griffin, N106 may never have even been assembled, though it was listed as ready for erection in October 1919. The relative success of the aircraft in its brief service is unclear, but its testing certainly showed promise. The poor layout of HMS Vindictive as an aircraft carrier probably did little to help the Griffin prove itself. Unfortunately, no further Griffins were ordered and the role was filled in the postwar Fleet Air Arm by the Parnall Panther.

The Panther appeared at a similar time to the Griffin but its performance was inferior in most respects, despite using the same Bentley BR2 rotary that had been fitted to some of the Griffins. Its speed was 7mph lower, its ceiling was 4,500ft lower and its climb to 10,000ft was five minutes slower than that of the Griffin. The Parnall flotation gear was found to be unfit for purpose and was replaced by the system developed at the Isle of Grain.

References:

JM Bruce, ‘Windsock Datafile 90. Sopwith B.1 & T.1 Cuckoo’
Owen Thetford, ‘The British Naval Aircraft since 1912’, Putnam
Ray Sturtivant and Gordon Page, ‘Royal Navy Aircraft Serials and Units 1911-19’, Air Britain
David Collyer, ‘Babies, Kittens and Griffons’, Air Enthusiast Issue 43