The Banjo sailplane is of mixed construction. Its 13.3 m (43.6 ft) span wing is strut-braced with one lift strut per side and uses a plywood box spar and spruce wing ribs, with the leading edge of the wing covered in plywood and the rear portion covered in aircraft fabric covering. The nose ribs are expanded polystyrene while the ailerons are made of wood and covered in fabric. The wing airfoil is an SM701 at the wing root transitioning to a Wortmann FX-60-126 at the wing tip, while the tailplane uses a Wortmann FX-71-L-150/30 airfoil. The fuselage is of fibreglass monocoque construction, while its one-piece bubble canopy is made from polycarbonate. The aircraft has fixed monowheel landing gear with a wheel brake and upper wing surface air brakes.
Variants:
Banjo
Unpowered single-seat sailplane with a 13.3 m (43.6 ft) span wing. Four were reported completed and flying in 1998. In production in 2011.
Banjo-MH
Powered version of the Banjo, with a retractable tractor configuration Hirth F33 two stroke 21 kW (28 hp) motor powering a two-bladed wooden propeller. Fuel capacity is 14 litres (3.1 imp gal; 3.7 US gal), gross weight is 260 kg (573 lb) and load limits +4 and -2g. The aircraft has a best glide ratio of 28:1. In production in 2011.
DuoBanjo
Two seats in tandem version, with two side-by-side main wheels mounted in the fuselage and a retractable tractor configuration Rotax 447 two-stroke 30 kW (40 hp) motor powering a ProFe 1.4 m (4.6 ft) two-bladed wooden propeller. Wing span is 16 m (52.5 ft), fuel capacity is 27 litres (5.9 imp gal; 7.1 US gal), gross weight is 460 kg (1,014 lb) and load limits +4.4 and -2.4g. The aircraft has a best glide ratio of 29:1. In production in 2011.
The Banjo wing is based on the SM701 airfoil, trapezoidal outer part is modified into FX-60-126. Wingtips are equipped with winglets. Basic element of the construction is a plywood, box section beam and ribs made from spruce scantlings. Front part of the ribs is made from expanded polystyrene. Leading edge of the wing is covered by plywood and forms a torsion box. Polyester fabric covers trailing part of the wing. On the upper part of the wing are located hinged aerodynamic brakes. Wooden construction ailerons are also covered by a polyester fabric. They are operated via Dural tube rods. Wings are supported by shaped struts. Wing is fixed to the fuselage by mountings located on the wing beam and on the trailing edge section.
Fuselage, including the tail fin, is formed from a fiberglass monocoque. Monocoque is reinforced by plywood ribs. Ribs are utilized as wings, struts, undercarriage wheel and rescue system mountings.
Cockpit (closed type) is covered by a one-piece canopy made from a splinter-proof polycarbonate (Makrolon). There is a ventilation window on the side of the canopy. Control stick is a classic style type. The cockpit is equipped with aerodynamic brakes lever (left side), rope release control (“T” shaped handle on the instrument panel) and trim handle. The cockpit is ventilated via ventilation outlets, located on the instrument panel. Adjustable pilot’s seat is equipped with 4-point safety belts.
The Banj MH Cockpit has engine throttle (left side), power unit position selector, ignition switch, starter, propeller stop control and main power switch (on the right side of the cockpit).
Fixed undercarriage consists of the main unsprung wheel (outer radius 400mm) and uncontrollable tail wheel (outer radius 140mm). The main wheel is fitted with a disk brake. The brake is operated via a cycle brake lever, mounted on the control stick.
Tail surfaces are “T” shaped. Horizontal tail surfaces have similar construction as the wing and use modified Wortmann FX-71-L-150/30 airfoil.
Controls and instrumentation. The instrument panel of the plane is equipped with the following instruments: airspeed indicator, combined electronic altimeter/variometer, compass and bank indicator. The Banjo MH instrument panel also has RPM gauge, fuel gauge, and engine temperature gauge. Power unit management panel is located on the right side of the cockpit. Instrumentation can be customized according to customer’s requirements.
The DuoBanjo is equipped with one instrument panel, containing following instruments: airspeed indicator, altimeter, variometer, RPM gauge, fuel gauge, engine temperature gauge, compass and bank indicator. Power unit management panel is located on the right side of the cockpit.
System of controls. Ailerons and elevator are operated via rods, equipped with swiveling joint ends. Levers are fitted with ball bearings. Rudder is cable controlled. Aerodynamic brakes are also cable controlled, in combination with springs. The DuoBanjo is equipped with dual set of controls, however lifting/retracting of the power unit can be controlled only from the front seat. Control sticks are classic style type. Seats are equipped with 4-point safety belts.
The powered Banjo power unit is based on the engine HIRTH F33 B, equipped with an electric starter, belt reducer and two-blade propeller. Power unit can be lifted or retracted into the enclosed power unit bay during the flight.
Fuel system. Alu fuel tank is located in the fuselage and it can contain 14 liters of the fuel. It is equipped with fuel float system, measuring quantity of the fuel in the tank. Filler neck is located on the left side of the fuselage, below the wing. The DuoBanjo has 27 liters of the fuel.
Electrical system. The main source of the energy is an on-board accumulator 12V-14Ah, which is recharged by the engine. The accu feeds the lifting/retracting system of the power unit together with the electric starter.
Specifications:
Banjo
Wing span: 13,3 m
Length: 6,3 m
Wing area: 10,5 sq.m
Main undercarriage wheel diameter: 400 mm
Tail wheel diameter: 140 mm
MTOW: 220 kg
Load factor: +4,4/-2,2 G
Max. speed VNE: 140 km/h
Max. speed in turbulence VB: 110 km/h
Stall speed: 50 km/h
Min. sink: 0,68 m/s
L/D: 28
Number of seats: 1
Banjo-MH
Wing span: 13,3 m
Length: 6,3 m
Wing area: 10,5 sq.m
Main undercarriage wheel diameter: 400 mm
Tail wheel diameter: 140 mm
MTOW: 260 kg
Load factor: +4/ -2 G
Max. speed VNE: 135 km/h
Max. speed in turbulence VB: 110 km/h
Stall speed: 60 km/h
Min. sink: 0,86 m/s
L/D: 28
Climb performance with MTOW: + 2m/s
Fuel tank capacity: 14 liters
Number of seats: 1
DuoBanjo
Engine: Rotax 447 UL DCDI 1V, 29 kW (6500 rpm)
Propeller: ProFe 1400mm
Wing span: 16 m
Length: 7,35 m
Height (propeller in retracted position): 1,57 m
Wing area: 13,86 sq.m
Aspect ratio: 18,3
Wing load at 460kg: 33 kg/sq.m
Number of seats: 2
Empty weight: 250 kg
MTOW: 460 kg
Max. weight of the crew: 200 kg
Min. pilot’s weight: 70 kg
Stall speed: 64 km/h
Maneuver speed Va: 130 km/h
Max. speed in turbulence Vb: 130 km/h
Max. speed Vne: 175 km/h
Min. sink (at 90 km/h): 0,9 m/s
Best L/D (at 100 km/h): 29
Cruise speed (5000 rpm): 110 km/h
Max. climb: 3 m/s
Load factor: + 4.4 / – 2.4 G
Fuel consumption, cruise: 9.5 l/h
Fuel tank capacity: 26 liters
