The Future of Advanced Air Mobility

Russian Government Backs Hybrid-electric Aircraft Developments

Last month’s MAKS air show held just outside Moscow provided a glimpse of several Russian electric aviation projects that have not yet received much attention outside the country. The fact that both projects enjoyed the attention of Russian President Vladimir Putin during his visit to the event provided evidence of the government’s commitment to advancing technology to make aviation more environmentally sustainable.

Two older aircraft are being used as flying testbeds for Russia’s Electrolyot (electric aircraft) program. The Side 48986 project (with “Side” being the Russian term for a non-commercial aircraft registration) has involved fitting eight electric motors beneath the lower wing of a piston engine Antonov An-2 biplane. The separate Side 87251 project is making use of a Yakovlev Yak-40 trijet to evaluate an electric propulsion system developed by Russia’s SuperOx company, featuring electric engines, superconductors, and a cryogenic cooling system. Both aircraft were available for close inspection on the ground and also took part in the MAKS flying display.

During the air show, Putin and Russian industry and trade minister Denis Manturov were briefed by engineers from the Zhukovsky Scientific Research Center, as well as several other of the country's state-backed institutes. Manturov confirmed that that the government is committed to supporting industry efforts to have electric- and hydrogen-powered aircraft in commercial service by around 2035. Current allocations of state funding for the work are due to end that year.

Meanwhile, the Urals Civil Aviation Plant (UZGA, to use its Russian acronym), is working on a hybrid-electric utility aircraft called the LMS-901 Baikal light utility eSTOL. The new type is viewed as a more energy-efficient and sustainable replacement for the An-2 biplane, which has been in production since 1946, and remains in service around the globe, including in China, where it is produced under license. A full-scale prototype of the Baikal was among the MAKS exhibits brought to President Putin’s attention during his tour of the show.

UZGA started work on the project in late 2019. The state-backed enterprise aims to begin deliveries to commercial operators in 2023.

With a maximum takeoff weight of around 10,560 pounds, the hybrid-electric aircraft is expected to be able to carry a 4,400-pound payload on flights of up to around 1,875 miles and at cruise speeds of 186 mph. Its powerplant consists of a Klimov VK-800SM turboprop engine combined with an electric propulsion system to drive a single nose-mounted propeller. The airframe itself features a strut-braced high wing and a fixed tricycle undercarriage.

According to Manturov, a combination of the hybrid-electric powerplant and a whole-aircraft safety parachute means that the Baikal will be able to exceed the current nine-passenger limit for types certified under Russia’s AP-23 rules (equivalent to FAA’s Part 23). The aircraft’s electric motors are installed beneath the wing in pods that also encompass tilting propellers.

Power generated by the main turboprop engine can be stored for use during all-electric mode, which UZGA says provides safety redundancy as well as efficiency. The company aims to certify the aircraft to carry up to 14 passengers.

“We want the Baikal to become our workhorse on the commuter air routes, to be our off-road vehicle able to use very short airfields,” said Manturov. Speaking during a briefing by UZGA, the government minister said the hybrid-electric aircraft will be well suited to operations in harsh and remote environments, requiring minimal support in the field.

Elements of the propulsion system now deployed on the Baikal prototype are now also being evaluated on an eSTOL technology demonstrator designated the Side 48986. The flying testbed was built by Chaplygin’s Siberian Scientific Research Academy in Novosibirsk (SIBNIA) and is based on the TVS-2MS model, which is a turboprop-powered version of the An-2.

The proposed model, which has been designated the Partisan, features a blown-wing design with eight podded electric motors. The tilting propellers with each electric motor can be deployed just for takeoff and landing and then stowed during cruise flight.

The Partisan program is sponsored by Russia’s Fund for Perspective Research, which also provided funds for the Side 87251 demonstrator under a project called Contour. It is intended to be able to operate from a standard helipad or in a remote area surrounded by trees or other obstacles with around 1,600 sq ft of clearance.

FPI project chief Yan Chibisov explained that the Partisan will be able to make short-field landings by cutting speed just before shutdown. The program may be expanded to include other applications of the propulsion technology for various eVTOL and eSTOL applications.