Published: August 02, 2018


What is the Viper SD4?

Viper SD4 is an all-metal two-seater microlight/LSA aeroplane, ideal for sports, entertainment, and recreational flying.  Viper is a great means for touring, pilot training, and glider towing.  Rich equipment includes – electric flaps, electric trim (elevator, aileron), autopilot, ballistic recovery system (AEPS).  The Viper SD4 has been certified by EASA and is even a great choice for Air Force pilot training.  The Viper SD4 is a single engine monoplane built by the Slovak company Tomark.  There are 2 variants, which are: ultralight vehicle (UL), or light-sport aircraft (LSA).  Light-sport aircrafts are very popular, due to their stable and maneuverability capabilities.


Price and users

Rotax 912 iS, 100 HP: US$ 139 900
Rotax 914 Turbo, 115 HP: US$ 159 900
Rotax 912 ULS100HP: US$ 124 900

Viper targets its users to be aviation enthusiasts, aircraft owners, flight schools, and Air Force pilot training.  Since the aircraft is very easy to fly (because it is a light-sport aircraft), just about anybody can fly it, from student pilots even up to commercial airline pilots.  Even if a 0 hour pilot flies this aircraft it will take very little time to get used to the controls since it is very easy to control.

Technical information and avionics






Wing span

8,4 m

/27 ft 4 in




6,4 m

/21 ft



2,2 m

/7 ft 3 in

Engine 4-stroke Rotax 912            HP


UL 80 HP/ULS 100

ULS 100 HP

Maximum take-off weight incl. BRS


472,5 kg  /  1 041 lbs

600 kg  /   1 320 lbs


Cruising speed

200 km/h  /  108 kts


Never exceed speed

240 km/h  /   130 kts


Stall speed

65 km/h  /  35 kts

75 km/h  /  40 kts


Climb rate

6 m/s  /  1 181 ft/min

5 m/s  /  984 ft/min



5 000 m  /  16 400 ft


Take-off distance


150 m  /  492 ft

180 m  /  590 ft

Landing distance

140 m  /  459 ft

160 m  /  524 ft


Fuel tank volume


70 l  /  18 US gal / 108.2 lbs

100 l  /  26 US gal / 158.8 lbs



750 km  /  405 nmi

1 100 km  /  594 nmi


The latest avionic technologies - wide utility options, excellent quality properties and a first-class design.  Top flight characteristics will be appreciated by not only experienced pilots, but also by training centres (flight schools), their flight instructors as well as beginner pilots.


Review of the Viper SD4 by Capt Gema Goeyardi


The chief pilot of 14DAYPILOT Flight Academy, Capt Gema Goeyardi had a chance to fly the Viper SD4 during the 2017 EAA AirVenture Oshkosh.  He did the test flight at Appleton Airport (KATW), and enjoyed his experience flying the aircraft.  According to him the aircraft is one the most comfortable in its class.  The flight characteristic is described as being very controllable (easy to control) and not too sensitive to handle.  He even tested the aircraft up to the speed of 120 knots, close to the never exceed speed.

The Viper SD4 has characteristics very similar with the Diamond DA20, because it has very accurate stability.  When maneuvering with the Viper SD4, increasing bank during steep turns from 45 degrees to 60 degrees is very easy to control, that rudder correction input is very minimal.  This is because the airplane is very stable and easy to control.

However, there are several things that Capt Gema found could be improved in the Viper SD4.  One of the things that Capt Gema didn’t like was that the braking was achieved by a handle that needs to be operated by hand.  This may be frustrating for some pilots, because most planes achieve braking by using the rudder pedals (by foot).  So, to be proficient in flying the Viper SD4 the pilot may need some time to get used to it.  To overcome this issue, customers may request to the manufacturer to customize the layout of the avionic and  braking system.


Our 14DAYPILOT administrator is an active aviation blogger who has high interest and expectations for the aviation industry.  Always up to date with the latest aviation news, our admin aims to provide the best content on our website to help all pilots alike.  We aim to provide flight training guidance and with information related to flying school materials and tips involved how to pass the check ride for all students.