Less than a month after revealing that the S-70 Okhotnik had taken to the skies for the first time, Sukhoi presented a redesigned version of its unmanned combat air vehicle (UCAV) at the MAKS international air show.
The main difference seen on the new model presented at Sukhoi stand is a flattened engine exhaust, which indicates a will to improve the stealth abilities of the UCAV, a flying wing which supposedly uses special materials and coatings to reduce its radar signature.
— Michael Jerdev (@MuxelAero) August 25, 2019
The S-70 demonstrator, that was shown flying on August 7, 2019, featured a round engine nozzle. A similar design can be seen on the 5th generation Su-57 fighter jet with which the UCAV should eventually operate, and whose mass production started in July 2019. At the time, the aircraft had flown for 20 minutes and reached an altitude of 600 meters (1,970 feet).
While offering 3D vector thrusting and thus improving maneuverability, the use of a circular exhaust also produces a lot of radio wave reflection and thus augments the radar cross-section (RCS). With this new exhaust design, the S-70 resembles more the likes of the Dassault nEUROn, whose stealth abilities were tested in early 2019, or the Northrop Grumman X-47B.
But the Sukhoi S-70 Okhotnik (Hunter) is way bigger than its Western counterparts. 20 meters in wingspan and a length of 14 meters, its mass is supposedly around 20 tons (against 4.9 for the nEUROn and 6.3 for the X-47B). It is expected to fly at a speed of 1,000 km/h, for a range of 6,000 km. Its two internal bays should embark up to 2.8 tons of weapons.
Initially a MiG program, the S-70 was given to Sukhoi in 2011. The UCAV started its ground testings in November 2018, when it reached a top speed of 200 km/h on the runway of the Novosibirsk Aircraft Production Association.