Intro

Viper SD4 is an elegant two-seater aircraft for every sunny day. Ideal not only for recreational flying, but also for a longer trip to the sea.

The reliable and durable all-metal construction of the proven Viper SD4 lower deck proved its worth in aviation training even when towing sailplanes. The AFT variant serves for the preparation of military pilots and the extended version of the Night-VFR the possibility of night flights, which together with the RTC model fitted with the Rotax 912 engine complies with the CS-LSA Amdt.1 regulation and bears the EASA.A.606 certificate. The aircraft is produced in ultralight/LSA/CS-LSA versions. At the same time, it is certified in several national environments and aviation categories.

The high torsional stiffness of aircraft coated with air duralumin reliably absorbs both air turbulence and the hard landings of novice pilots. Proof of durability of the materials used are still flying machines from the Second World War, based on the same all-metal philosophy with easy maintenance. Although the Viper has been ranked among the world leaders in the field of safety and airworthiness by the brave handling of the corkscrew test, the all-aircraft parachute rescue system (AEPS) serves for maximum safety. In the worst case scenario, you can activate a parachute built into the fuselage of the aircraft, on which the entire machine calmly descend to safety, from where the ELT function automatically informs the emergency services about the position of the crew.

Emotion

Design

As the three-leaf propeller spins, you leave the earthly world of the mundane and enter a new dimension of vast possibilities. Traffic jams and traffic lights cease to exist for you. If you let the autopilot to do the flying, you can rest easy. All destinations are closer to you as the crow flies, and thanks to lower consumption, flights will be cheaper compared to cars.

Inspired by aerodynamic elegance and freedom, the design DNA of the Viper SD4 depicts the unmistakable contours of an honestly designed and thoroughly constructed machine in the sky. The consequence of the interplay of function and shape without room for compromise is a large effective direction indicator. The sense of perfection in every detail cannot be overlooked with every single thoroughly melted thread, reducing aerodynamic resistance.

Original

Slovak origin

Domestic top experts for aeronautical development, construction and modelling have designed the Viper SD4 from the first to last screw in Prešov, where precision metal semi-finished products are subsequently carved with the most modern laser technologies. These are then machine-bent and shaped into precisely designed compensators for the construction of the basic centerplane, rectangular wings, tail surfaces and other parts. Finally, the engine is mounted and instrumentation is installed, culminating in the inspection and take-off of the finished aircraft by a professional test pilot.

Ergonomics

Interior

You will understand that you have made the right choice when boarding comfortably. The rear-opening cabin makes it easy for you to slip into the cockpit, which offers several variants of flight, navigation and communication equipment layout. You can store your luggage behind your back without disturbing the machine’s excellent delivery, and the low edge of the dashboard opens up a wide panoramic view.

Parameters

Flight properties

Stability and certainty from graceful take-off to the clouds. Peaceful horizontal flight at a steady altitude smoothed out by agile electric trim at a clip. Finally, a soft landing on an asphalt or grass surface dampened by a wide, well-spring-loaded chassis. These are attributes that inspire trust even in a complete beginner. Thanks to winglets at the wing ends, Viper SD4 achieves a high glide speed of 10 km from a height of 1 km, which is why experienced pilots are world leaders in their category in this aircraft with electrically operated flaps.

The three-wheeled chassis

of the front type is divided into a main chassis and a front chassis. The main chassis is made of composite springs. Its wheels are braked by hydraulic disc brakes. The brakes are operated centrally by a lever placed on the center panel between the seats. The front steerable chassis is spring-loaded with rubber rope. The wheels of the chassis can be equipped with aerodynamic covers.

Duplicate steering

in a classic configuration with a steering wheel and wings operated by means of drawbars and a steering wheel controlled by ropes.

Three-blade propeller

chosen with respect to the engine installed in such a way that it does not restrict flying in the permitted modes of operation with respect to the speed allowed. Both fixed and adjustable versions may be used.

All-metal rectangular wings

with composite tips are equipped with wings and slotted lift flaps operated electrically in three positions. The wing roots contain fuel tanks.

Tail surfaces

the classic configuration will consist of a horizontal and vertical tail surface. The horizontal tail surface consists of a continuous stabilizer with right and left elevators, which are interconnected by the steering model and equipped with an electrically operated counterbalance surface. The vertical tail surfaces form the keel surface and the rudder.

Two-seat cabin

je vybavená trojbodovými bezpečnostnými pásmi. equipped with three-point safety belts, it is covered by a highly retractable windscreen and secured by a lockable door with practical opening upwards. The ventilation is designed with compressed air collected on the sides of the fuselage with the outlet through two ventilation holes built into the dashboard. In winter, the crew will appreciate the space heating.

Towing device

as an optional accessory, it is used for towing non-powered aircraft with a take-off weight of up to 750 kg.

Aircraft hull

forms a tubular bulkhead structure combined in the rear with a semi-shell bulkhead structure reinforced with reinforcements and duralumin coating. The hernial surface is an integral part of the hull. The engine compartment shall be separated from the crew compartment by a steel fire wall.

Fuel system

consisting of two winged integrated lockable tanks equipped with fuel meter floats, a defrosting valve, a fuel line, a main fuel valve, a fuel filter and an electric flood pump.

Boxer engine

the Rotax 912 ULS/S is a two-carburettor four-stroke four-cylinder with water-cooled heads and air-cooled cylinders with a capacity of 100 HP.

	UL	UL/LSA
Wing span	8,34 m (27,4 ft)	8,34 m (27,4 ft)
Length	6,40 m (20,1 ft)	6,40 m (20,1 ft)
Height	2,20 m (7,3 ft)	2,20 m (7,3 ft)
Engine 4-stroke Rotax 912	UL 80 HP \| ULS 100 HP	ULS/S2 100 HP
Propeller, 3-blades, ground adj.	CUSTOMIZED	CUSTOMIZED
Cruising speed	200 km/h (108 kt)	200 km/h (108 kt)
Stall speed	65 km/h (35 kt)	75 km/h (40,5 kt)
Climb rate	6 m/s (1 181 ft/min)	5 m/s (984,3 ft/min)
Take-off distance (ground roll)	150 m (492 ft)	180 m (590ft)
Landing distance (ground roll)	140 m (459 ft)	160 m (524,8 ft)
Durability	3 hrs 45 min \| 6 hrs	6 hrs
Range	705 km (381 nm) \| 1 000 km (648 nmi)	1 200 km (648 nmi)
Consumption (NAT 99+) / 1 hour	16 L (4,2 US gal)	16,4 L (4,3 US gal)
Tank volume	70 L (18,5 US gal) \| 100 L (26,4 US gal)	100 L (26,4 US gal)
Max. take off weight incl. BRS	475 kg (1 047 lbs) \| 600 kg (1 320 lbs)	600 kg (1 320 lbs)