No. 10912. Latham L.1 (F-ESEJ c/n 02)
Source unknown

Latham L-2

10/31/2011. In 1922, after the two CAMS 36 flying-boats had been prevented from reaching Naples for that year's Schneider contest, France determined to mount a thoroughly pragmatic approach to its preparations for the 1923 contest at Cowes. From its careful examination of the CAMS 36bis and the newer CAMS 38 flying-boats it was clear that, while both aircraft were of conventional design and construction, they were not wholly suited to the rigors of the heavy weather which the British Isles can produce at almost any time of the year.

For this reason it was decided to adopt a belt-and-braces policy with regard to the French team aircraft and build a more robust design better equipped to face bad weather conditions in the Solent (a strait separating the Isle of Wight from the mainland of England). Accordingly, the Société Industrielle de Caudebec-en-Caux (SICC) was given an order for two single-seat flying-boats to meet this requirement.

Designed by M. Latham, a cousin of the famous French pioneer pilot, they materialized during 1922-1923 as twin-engined aircraft with their 400 hp Lorraine-Dietrich 13 twelve-cylinder V-engines in a tandem installation. The single-step hull was of conventional construction with its wooden formers overlain by wood strips. The hull had a deep V-bottom with hard chines which swept forward up to the stemhead, while the rear hull curved up to the integral fin.

The pilot's open cockpit was positioned between the two front engine-mounting struts and behind the front propeller and had an air dam rather than a transparent windscreen. The tail plane was carried on top of the fin and a comma-shaped rudder extended above and below the tail plane which was braced to the hull by a single swept broad-chord strut.

The single-bay rectangular plan main planes had the usual two spruce main spars with plywood ribs, all fabric-covered, and single 'I' broad-chord inter plane struts. Long-span ailerons were carried on the upper and lower main planes and were interconnected by a streamlined rod. The wing bracing of the Latham L.1 was a novelty, described in the October 4, 1923 issue of 'Flight, The Aircraft Engineer and Airships' as follows:

"A feature which is new to us was noticed in the wing bracing, which consisted of laminated streamline wires. We believe that M. Latham has patented this form of wire, which consists of several separate wires placed side by side, the inner one being of the greatest width, the next ones narrower, and so on. Thus in case of a flaw in one lamination the complete wire is only weakened somewhat, but has still, if the factor of safety has been chosen high enough, more than sufficient strength for its work. The idea seems to have a good deal to recommend it, and might be worth investigation."

The arrangement of the engine mounting struts differed on the two aircraft. On No.1, F-ATAM, c/n 01 (site files), the engines were mounted on a pair of single struts at the front-to which two long Lamblin radiators were attached-and by a pair of V-struts at the rear. Two pairs of inverted V-struts on each side supported the upper main plane centre-section. The front engine was housed completely within the bulky nacelle but the aircraft was sometimes flown with the top of the rear engine uncowled.

On No.2, F-ESEJ, two pairs of V-struts supported the engines' nacelle front and rear and it is believed that the tops of both engines were permanently uncowled as indicated in contemporary drawings. On both aircraft a fin-type oil cooler was fitted in the bottom of the nacelle between the two engines. The whole of the wing cellule was braced by streamlined wires. Two 'trousered' stabilizing float structures were attached directly under the lower main planes.

The two engines were not 'handed' and thus both rotated in the same direction; as they were mounted back-to-back they turned their respective two-blade fixed-pitch wooden propellers, which had curved scimitar-like blades, in opposite directions and cancelled out the torque reaction.

As the date of the contest drew near it began to be apparent that there could be a repetition of the previous year's non-appearance of the French entries; however, both L.1s were readied for their journey to Cowes aboard ship only two days before the all-important navigability trials were scheduled to begin. When the ship which was to have taken the two CAMS flying-boats went unserviceable, it was decided to switch the shipping arrangements and fly the Latham L.1s across the Channel, leaving the one available ship to bring the more frail CAMS aircraft.

During the cross-Channel flight to Cowes by the two Latham L.1s, F-ATAM flown by M. Benoist had engine trouble and diverted to Littlehampton, where it was damaged by surf and by the misguided enthusiastic assistance of eager but amateur Britons. As a result, it was withdrawn from the contest. F-ESEJ, flown by M. Duhamel, arrived safely at Cowes, a subsequent magneto failure on one of the engines also prevented its participation in the contest.

Created October 31, 2011