1. Design and development

2. Specifications (Anzani engine)

3. Notes

4. References

The Albessard Triavion, sometimes known as the Peyret-Albessard Triavion, was a three surface aircraft, combining a tandem wing and conventional tailplane.

Design and development

In 1912 L. J. A. Albessard applied for a patent on a naturally stable aircraft which was published in February 1913.^[1] This was followed in 1914 with a four-seat tandem wing transport. Tandem wing aircraft had been flown before, for example the Bleriot VI in 1907, but the Albessard design differed in retaining a conventional tail unit.^[2][3][4] The 1926 Albessard Triavion further developed this layout. It was built by Louis Peyret,^[5] the designer of the world record breaking Peyret Tandem, a tandem wing glider. The overriding aim of Albessard's designs was safety, even if this compromised manoeuvrability and speed, with automatic stability and a soft stall achieved by locating the centre of gravity at the combined centre of lift of the two wings, combined with structural strength. The Triavion was wood-framed and plywood skinned throughout.^[5][7]

The two wings, both with straight, slightly swept leading edges, were mounted in tandem in the top of the fuselage. It was well known that such an arrangement led to an aerodynamically inefficient rear wing, as it was in the downwash of the forward wing, so Albessard gave the inner panel of the latter a symmetric section set at 0° angle of incidence that produced no lift or downwash in level flight. This {{convert|7.50|m2|sqft|abbr=on}} area inner panel, with a slightly narrower chord than the outer panels, had a span almost as large as that of the rear wing. The outer, cambered panels, connected to the inner with short junction sections, were set at an incidence of 3° and produced lift. The rear wing was simpler and of constant chord, as broad as the outer forward wing panels and having 1.4 times their area. The wings were separated by about twice the rear wing chord. Together, the two forward outer panels and the rear wing produced a triangle of parallel lift vectors leading, according to Albessard, to the aircraft's stability.^[5][7] There were ailerons both on the forward outer panels and on the full span of the rear wings. These were operated differentially and could be used either as conventional ailerons or as camber changing devices.^[10]

The Triavion's fuselage was rectangular in cross-section, flat sided and bottomed but topped with a triangular section decking through which the wings passed. The forward wing was braced to the lower fuselage longerons with two pairs of parallel lift struts on each side, one pair to the neutral lift inner section and the other to the outer panels. These pairs had horizontal and vertical jury struts between them. A pair of N-form struts angled outwards from the upper longerons to form a cabane supporting the centre section of the wing. The shorter rear wing needed only a single parallel pair on each side from the lower fuselage with similar upper longeron N-struts. Its {{convert|70|hp|hp|abbr=on}} six cylinder, radial Anzani engine was mounted in the nose. The forward cockpit was just under a V-shaped cut-out in the centre section trailing edge and the second was midway between the two wings; both were within the triangular decking, which had large openings in it, and there were also round apertures in the sides to improve downward vision. Both cockpits were accessed via starboard-side doors. The empennage was conventional, with a large, upright fin and a vertical edged unbalanced rudder that went down to the keel; the cantilever tailplane and elevators were rectangular in plan, with rounded corners and a cut-out for rudder movement, and were mounted a little lower than the wings on the upper fuselage longerons. It had conventional landing gear with mainwheels on a single axle rubber sprung to V-struts from the lower fuselage, their rear members part of a transverse inverted W-form strut also joined to the central fuselage. There was a short tailskid.^[5]

Some sources give the date of the Triavion's first flight as 10 August 1926;^[12] it certainly flew at the Concours d'Avions Economique which began on that date at Orly; though originally registered as a competitor it only arrived mid-week and did not take part in the contest.^[13] After tests and modifications, it received its certificate of airworthiness on 3 October 1927.^[14] Sometime in that year it was fitted with a {{convert|95|hp|hp|abbr=on}} Salmson 7AC seven-cylinder radial engine.^[5] It was later sold to the state. After aileron flutter was induced in a full power dive, L'Ailes wrote an article characterising it as a reliable carthorse rather than a highly strung racehorse.^[17] Despite test flights over two years covering more than {{convert|6000|km|mi|abbr=on}} with seven pilots who responded positively to its simple throttle and aileron controllability and refusal to stall violently or spin, plans for a second aircraft found no buyers.^[7]

Specifications (Anzani engine)

|genhide=
|crew=one pilot
|capacity=one passenger
|length m=7.00
|length note=
|upper span m=11.50
|upper span note=front wing
|lower span m=7.60
|lower span note=rear wing
|height m=2.00
|height note=
|wing area sqm=18.50
|wing area note=total lifting area; rear wing area 58% of total
|aspect ratio=
|airfoil=
|empty weight kg=320
|empty weight note=
|gross weight kg=550
|gross weight lb=
|gross weight note=
|max takeoff weight kg=
|max takeoff weight lb=
|max takeoff weight note=
|fuel capacity=
|more general=

|eng1 number=1
|eng1 name=Anzani
|eng1 type=6-cylinder radial
|eng1 hp=70
|eng1 note=
|power original=
|more power=
|prop blade number=2
|prop name=
|prop dia m=
|prop dia ft=
|prop dia in=
|prop dia note=

|perfhide=
|max speed kmh=125
|max speed note=all performance figures calculated
|cruise speed kmh=
|cruise speed mph=
|cruise speed kts=
|cruise speed note=
|stall speed kmh=65
|stall speed note=minimum speed
|never exceed speed kmh=
|never exceed speed mph=
|never exceed speed kts=
|never exceed speed note=
|minimum control speed kmh=
|minimum control speed mph=
|minimum control speed kts=
|minimum control speed note=
|range km=650
|range note=
|endurance=
|ceiling m=480
|ceiling note=
|g limits=
|roll rate=
|glide ratio=
|climb rate ms=
|climb rate ftmin=
|climb rate note=
|time to altitude=
|sink rate ms=
|sink rate ftmin=
|sink rate note=
|lift to drag=
|wing loading kg/m2=
|wing loading lb/sqft=
|wing loading note=
|disk loading kg/m2=
|disk loading lb/sqft=
|disk loading note=
|fuel consumption kg/km=
|fuel consumption lb/mi=
|power/mass=
|thrust/weight=
|more performance=
}}

Notes

References

• John Lancelot Cowan
• John Lancelot Lithgow
• John Lancelot Stirling
• John Lancelot Todd
• John Landa
• John Lander Harper
• John, Landgrave of Lower Hesse
• John Landon
• John Landowski
• John Landquist
• John Landseer
• John Landsteiner
• John Landyran
• John Lane (poet)
• John Laney
• John Laney (disambiguation)
• John Langan
• John Langdon Davies
• John Langdon (disambiguation)
• John Langdon (historian)
• John Langdon Parsons
• John Lang (footballer, born 1881)
• John Lang (footballer, born 1908)
• John Langford Pritchard
• John Langford (rugby)