Single seat single engined parasol winged air¬craft with conventional three axis control. Wing has unswept leading and trailing edges, and constant chord; V tail. Pitch/yaw control by elevon; roll control by ailerons; wing profile Clark Y; double surface. Undercarriage has three wheels in tail dragger formation. Aluminium tube/wood fuselage, partially en¬closed. Engine mounted at wing height driving tractor propeller.
Began in 1974, it was not until July 1977 that the aircraft, a joint venture between Kazimierz Jarzab, S Kustron and S Wojton, made its first flight. It is a parasol winged tail dragger constructed largely from wood and aluminium alloy. The pilot sits under the wing, in an open cockpit but protected by a windscreen, and the two blade pusher propeller is mounted at the trailing edge of the wing. A tubular empen¬nage supports the V tail, which has in addition two fins, shaped like an isosceles triangle with rounded corners.

Length overall 13.8 ft, 4.20 m.
Height overall 3.6ft, 1.10m.
Wing span 23.0ft, 7.0m.
Constant chord 2.8ft, 0.86m.
Sweepback 0 degs
Total wing area 65 sq.ft, 6.0 sq.m.
Wing aspect ratio 8.2/1.
Engine: MZ 250, 16 hp.
Power per unit area 0.25 hp/sq.ft, 2.7 hp/sq.m.
Fuel capacity 5.3 US gal, 4.4 Imp gal, 20.0 litre.
Empty weight 209 lb, 95kg.
Max take off weight 419 lb, 190kg.
Payload 209 lb, 95 kg.
Max wing loading 6.45 lb/sq.ft, 31.7 kg/sq.m.
Max power loading 26.2 lb/hp, 11.9kg/hp.
Cruising speed 68mph, 110kph.
Max climb rate at sea level 400ft/min, 2.0mls.
Take off distance 660ft, 200m.
Range at average cruising speed 622 mile, 1000km.

In 1986 at SKB JAI a light aircraft named JAI-40 (Russian: ХАИ-40) and nicknamed “VOK” was developed. Originally this device was obtained as a student work directed by G. Jmyz from the previous JAI-21. The aircraft was safe, light in handling and excellent speed and economy characteristics.

The JAI-40 was designed as a mixed construction single-seater high-wing monoplane. The wing, braced by inverted V posts, was constructed of wood with some use of composite materials and featured control surfaces along the entire length of the trailing edge.

The bar-type fuselage was constructed of metal tubes and sheets.

The glue unit was conceived on the basis of a fabric-coated duralumin tube structure. The horizontal planes were located high above the empennage and were braced to the structure by cables. The rudder featured a large area.

The landing gear was designed in a tricycle configuration. The front wheel was of the steerable type and was located directly at the bow of the device. The pilot sat in a seat on the basic structure of the fuselage. To avoid impacts during landing at large approach angles, a skid was installed under the rear of the fuselage.

The drive configuration difficulties were offset by installing a 35 hp RMZ-640 geared motor. This engine was installed directly on the vertical pylon for fixing the wings, moving a propeller with two wooden blades 1.38 meters in diameter. The selection of the engine and the use of a wing with 8.2 aspect ratio allowed the model to fly easily and have an excellent take-off step. Later and in order to improve performance, a 42 hp Vulcan engine designed by VP Manuilenko would be installed, moving a propeller of 1.51 meters in diameter.

Its further development was reinforced and in 1988 it reached first place in its class in the light aircraft competition held in Túshino. With a takeoff weight of 305 kg and a 42 hp engine this little machine was capable of reaching 105 km / h.

The JAI-40 successfully participated in the SLA-87 light aircraft competition.

JAI-40
Engine: 1 x Vulcan 42 hp
Wingspan: 8.50 m
Length: 4.75 m
Wing area: 9.60 m²
Tailplane wingspan: 5 m
Vertical fin area: 1.64 m²
Rudder area: 0.90 m²
Queue area: 1.40 m²
Elevators area: 0.86 m²
Wing aspect ratio: 8.7
Wing Profile: GA -1
Wheel spacing: 2.05m
Empty weight: 172 kg
Gross weight: 262 kg
Maximum takeoff weight: 305 kg
Wing loading: 2.44 lb / sq.ft
Power load: 7.48 kg / hp
Fuel capacity: 10 liters
Maximum speed: 105 km / h
Cruising speed: 95 km / h
Stall speed: 55 km / h
Ascent speed: 128 m / min
Practical range: 90 km
Accommodation: 1

JAI-37 “Mikhail Yefimov” (Russian: ХАИ-37 “Михаил Ефимов”) was an ultralight aircraft developed at the AKA of the JAI.

Structurally, the JAI-37 was conceived as a high-wing braced monoplane of mixed construction. The ailerons were located at the wing tips. These ailerons appeared as increases to the wingspan.

A modified “Vijr-30” naval engine with air cooling was used as the power plant for this implementation and with a takeoff power of about 28 hp.

The JAI-37, named Mikhail Yefimov, was built in 1982 by a group of JAI students from a project developed by V. Dombrov, who also directed the construction. In this process, V. Kozhushnov, S. Kurinni, R. Sielix, M. Boiko and I. Tkach stood out.

First flying in 1980, as a glider, and August 1981 powered, tests were not good due to the lack of effectiveness of the wingtip ailerons.

Based on JAI-37, the improved JAI-37M model was developed with modified wings and tail and more standard placement of the ailerons. Later another model would be built, known as JAI-37M2.

The JAI-37M participated in the First SLA-85 Light Aviation Competition, but in this competition it did not fly.