Latécoère Trombe
History
The Latécoère Trombe ("Waterspout") entered development in February 1943 as a private project commissioned by the Latécoère company, on the basis of speculation within the French Navy at the time. A small group of French naval aviators voiced concerns about whether or not the current classes of aircraft carriers in the Marine Nationale could handle projected jet fighters and bombers. The greatest concerns evolved around the question of whether or not the long take-off and landing runs of the early turbojet aircraft would make current carriers outdated. Conventional wisdom within the Aeronavale determined that the Bucentaure and Vengeur class carriers would have sufficient length and beam to operate jet fighters. However, a minority of aviators disagreed, and considered options for putting jet aircraft into naval service in the event the current generation of carriers proved incapable.
Research progressed along two separate lines of development. The first, which proved to be a technological dead-end, focused on developing a jet aircraft that launched vertically from a tail-sitting position, and then landed in exactly the same way. Proponents of this idea believed that this method would allow extremely rapid launches of large strike wings from relatively small flight decks. However, little progress was made and no major aircraft manufacturers demonstrated an interest in starting a design project in light of the engineering hurdles to be overcome, particularly when the mainstream decision-makers in the Aeronavale were derisive of the idea. Nevertheless, several drawing proposals were circulated both for aircraft and ships designed to carry them (including an ambitious five-thousand ton "convoy escort-carrier" intended to carry twelve vertical-launched fighter interceptors).
The second and more conventional line of development focused on the development of a turbojet-powered flying boat, similar in theory to the floatplane fighters and bombers popularized in French service during the 1920s and 1930s. As a flying boat could take off and land from the surface of the ocean, minimum takeoff distances no longer became a consideration. Floatplane tenders already existed and could be constructed for less cost than a fleet carrier, and flying boats could be used from almost any sheltered lagoon or harbor. These ideas required relatively little in the way of new technology, and in February 1943 the Latécoère company determined to pursue a development project using their existing expertise in floatplanes and flying boats.
Despite lacking any experience whatsoever with turbjojets, Latécoère's designers moved ahead quickly to develop a prototype for review by the Aeronavale. Latécoère's emphasis lay in a mix of speed (which the Aeronavale wanted) and range (which Latécoère's designers felt was more desireable). By July 1944, Latécoère unveiled a quarter-scale mockup for the Aeronavale, which signed a contract to continue funding development and construct two aircraft prior to April 1945 for testing.
Latécoère's design followed several interesting directions. The Trombe's flying-boat body was designed for relative minimalism, being deep and narrow. The pilot sat far forward, in a position with excellent visibility, while the single axial turbojet was located in a pod mounted on the aircraft's back, in order to keep both the inlet and nozzle clear of spray during landing. This quickly gained the Trombe the nickname "the Hunchback of Biscarosse". The engine exhausted between the 50-degree V-tail. While on the surface, a pair of shaped fiberglass outriggers, normally flush inside the fuselage, automatically folded down in order to increase bouyancy and stability. The wingtips each had a small pod which contained an inflatable rubber bladder, designed to keep the wingtips from dipping too far into the water. During takeoff, the bladders would deflate and retract back into the pods to reduce drag. Armament was decidedly minimalistic, consisting solely of a pair of DEFA 23mm cannons located in the wing-roots, with shell ejector ports located under the wing (in order to keep spent cartridges away from the engine inlet).
Starting in August of 1944, Latécoère began construction of the two initial test aircraft, the first of which was completed in February 1945, while the second was completed in April. However, neither aircraft flew until May; the initial turbojet engine delivered to Latécoère was damaged in transit, and no spare was provided for three months. When an engine finally became available in April, it was not the Gnome-Rhone TRAC-1C Curtana engine originally designed for, but a significantly more-powerful and centrifugal-flow Rateau-Anxionnaz A.63. Hasty alterations were made to the airframes and the first aircraft flew in late May. Although the larger engine slightly unbalanced the aircraft's center of gravity, the excess power and better fuel economy proved vital in nearly achieving the Trombe's stated design objectives (namely a speed of four hundred knots and a range of eight hundred kilometers).
The Aeronavale was not deeply impressed with the Trombe. By 1945, more experts in the Aeronavale were confident that the upcoming generation of jets could in fact operate from the large French fleet carriers. Despite this, no serious opposition to the "hydravion jet" concept formed, and a limited production run started in late 1945. Most of the aircraft produced were assigned to land-based squadrons deployed in Nouvelle-Calédonie, Fidji, and Polynesia.
General characteristics
Crew:
Length: 12.15 m
Wingspan: 10.6 m
Height: 3.9 m
Wing area: 24.9 m²
Empty weight: 3,384 kg (7,460 lb)
Loaded weight: 5,036 kg (11,102 lb)
Max takeoff weight: 5,500 kg (12,125 lb)
Powerplant:
- Initial Proposal: 1 × Gnome-Rhone Curtana TRAC-1C axial turbojet 9 kN (918 kgf / 2,023 lbf thrust)
- Testbeds / Production: 1 × Rateau-Anxionnaz A.63 turbojet, 17.5 kN (1,784 kgf / 3,934 lbf)
Performance
Maximum speed: 725 km/h (391 knots, 450 mph)
Combat radius: 950 km
Ferry range: 1550 km
Service ceiling: 9,000 m
Rate of climb: 18.3 m/s
Armament
Guns: 2 × 23 mm DEFA cannon with 125 rounds per gun
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