After the success of the Sinus it was quite realistic to expect there is also a market niche for a real microlight two-seat glider, as well as it's version with an auxiliary, fully retractable engine. Hard-core glider pilots were not convinced by the glide ratio of 1:30 that Sinus has to offer. The 'real' quality gliding goes together with glide ratios of 1:40 and more.
This time, the main idea of construction was different from the Sinus, but the aims were a side-by-side microlight motorglider, with a self-lauchable version with an auxiliary, yet fully retractable engine and glide ratio of at least 1:40.
by providing two main wheels in parallel configuration complete independence could be achieved dispensing with a helper holding the wing tip during take-off.
The fuselage of Taurus uses a lifting body shape concept and features enough room for an auxiliary, yet fully retractable engine.
Taurus is also intended for training, therefore all controls must be within reach of both pilots. Both pilots have individual control sticks and rudder pedals. The landing gear operation lever, flaps, airbrakes, tow rope release and trim levers are there for common for both pilots and are found in the middle, between both seats. For added comfort pilots enjoy adjustable headrests, in-flight adjustable rudder pedals, separate vent window and a central ventilation system for efficient de-fogging of glass surfaces. There are side pockets for each pilot and a baggage compartment behind the seats with space for an oxygen system as well.
The version of Taurus with an auxiliary retractable engine comes with a ROTAX 503 which is modified and redesigned by Pipistrel. The engine is twin carbureted engine and drives Pipistrel's own developed propeller. The system for extending and retracting the engine and propeller is fully automated. The pilot takes advantage of a dedicated interface on the instrument column and all they have to do is to flick the switch to 'engine IN' or 'engine OUT' position – everything else is done completely automatically. When retracting, the propeller is first positioned vertically, the engine then gets retracted and the engine bay covers close. To restart the engine on ground or in-flight the pilot selects the 'engine OUT' option and the engine extends and is ready for start-up in only 12 seconds. The entire engine retraction system is incredibly light and reliable, all switches and sensor used to monitor the operations are electromagnetic-induction type and as such not sensitive to vibration, mechanical damage and/or dirt. This system has also been developed in-house by the Pipistrel team. Built-in safety will prevent inadvertent start-up or retractions of the engine.
The same goes for the undercarriage retracting system, which is fully mechanic but needs very light force on the cockpit lever during operation. There are two main wheels in parallel configuration. The tail wheel is not retractable but fully stearable. The airbrakes, flaps and the elevator trim are all mechanical pushrod type. A tow-rope release mechanism can be fitted as well. Gliding has a 1:41 glide ratio coupled with 5 flaperon settings.
The LSA Taurus has a 15-meter wing-span which can be removed. Taurus has automatic control connections and one wing weighs 40 kg (90 lbs). From take-off to 500 m (1650 ft) needs only 3 minutes, 6 minutes to 1000 m (3300 ft) and 10 minutes to 1500 m (5000 ft).
Taurus entire cabin area is encased with energy absorbing structures made from Kevlar fibre. The Taurus can also be equipped with the ballistic parachute rescue system. Taurus is made in highest technology composites (epoxy resin, glass fibre, carbon fibre, kevlar fibre and honeycomb structures). The airfoil used on wings is ORL 170, (F. Orlando).
2009 Price: 70000 EURO
First announced in December 2007, the Taurus Electro matches the performance of the petrol powered Taurus 503 and, it weighs the same and sells for the exact same price. Taurus Electro has a tailor-developed 30 kW electric motor.
The electric-motor propulsion has been tested successfully on four light aircraft before the Taurus Electro – as an auxiliary engine on self launching gliders Apis, Antares and Silent and on the MCR light aircraft where a full-cell based propulsion was used.
Pipistrel's Taurus is a two-seat glider with higher approved take-off weight than the single seat gliders where the electric-motor propulsion has been tested so far. Therefore the Taurus requires a more powerful electric motor.
The goals when designing the Taurus Electro were mainly to:
- develop a system, that will enable the aircraft to climb to altitudes in excess of 2000 meters on a single battery charge;
- keep the current market price of the aircraft;
- keep the current take-off distance;
- keep the empty weight of the aircraft within the values of the internal combustion engine powered Taurus 503 with fuel;
- keep the current climb profile of the aircraft.
This required modify the existing system for extension / retraction of the engine, developing a purpose-built propeller to maximize the efficiency at given constant torque, useing high-performance Lithium-polymer batteries with specific capacity touching 200Wh/Kg, and developing a system to charge the batteries in flight.
Developmental costs of the Taurus Electro project were over 1 Million Euro, partially funded by the EU for the sum of 354,824.89 EUR.
Engine: Rotax 503 UL DCDI 2V, 53 hp at 6600 rpm
Propeller: 2 blade Pipistrel 1600 mm diam
Wing span: 14.97 m
Length: 7.27 m
Height: 1.41 m
Wing area: 12.33 sq.m
Rudder area: 0.9 sq.m
Horizontal tail area: 1.36 sq.m
Aspect ratio: 18.6
Positive flaps: 5 deg, 9 deg, 18 deg
Negative flaps: -5 deg
Center of gravity: 23% - 41%
Empty weight: 285 kg
Minimum pilot weight: 60 kg
Maximum total pilots weight: 220 kg
Max take off weight (MTOW): 450 kg / 472.5 kg
Fuel tank capacity in the wing: 30 lt
Useful fuel: 27 lt
Stall with flaps: 63 km/h
Stall without flaps: 71 km/h
Manoeuvring speed: 163 km/h
Max. Speed with flaps extended: 130 km/h
Max. Speed with airbrakes extended: 225 km/h (extend at or below 160 km/h)
Max. Speed with powerplant extended: 160 km/h
Vne: 121 kt / 140 mph / 225 km/h
Min.sink: 0.70 m/sec
Min.sink speed: 94 km/h
Max. Sink with airbrakes: 6.0 m/sec @ 100 km/h
Best glide: 1: 41
Best glide ratio speed: 107 km/h
Best glide at 150 km/h: 1: 33
Best glide at 180 km/h: 1: 23
Max towing speed: 150 km/h
45°-45° roll time: 3.9 sec
Take off run MTOW: 180 m
Take off over 15 m MTOW: 265 m
Cruising speed with 75% power: 120 km/h
Best climb speed: 100 km/h
Max climb rate (MOW): 2.9 m/sec
Service ceiling MTOW: 3,900 m
Max load factor permitted (x1,8): +5.3g -2.65g
Max load factor tested: + 7.2g - 7.2g
Fuel consum. At full power:: 18 lph
Cockpit width: 50 in
Empty weight (incl. Batteries): 320 kg
Top-of-climb: 2000 m / 6500 ft AGL
Take-off distance at MTOW (472.5 kg): 170 m / 560 ft
Climb rate at MTOW (472.5 kg): 2.8 m/sec / 560 fpm
Electric motor type: permament magnet synchronus three-phaes brushless
Electric motor dimensions (excl. propeller flange): diam. 250 mm x 150 mm
Electric motor mass (excl. propeller flange): 14 kg
Max. continous shaft power: 30 kW at 1800 RPM
Efficienty at max. continous power: 95%
Max. continous torque: 160 Nm
Peak torque: 200 Nm (0 – 1500 RPM)
Max. motor RPM: 1800 RPM
Nominal voltage: 140 V
Propeller diameter: 2040 mm
Batteries: Lithium-polymere: 42 cells, 3.7 V each
Storage capacity: 6 kWh
Battery weight: 46 kg
Charger / battery voltage balancer: Built into aircraft
Power / RPM controller: SAC 40 modified for aviation use