Technical data
Type	KhAI-4 'Iskra'
Function	Experimental
Year	1934
Crew	2
Engines	1*100hp M-11
Length	4.2m
Height	?m
Wingspan	12.0m
Wing area	21.25m2
Empty weight	550kg
Loaded weight	850kg
Wing Load (kg/m2)	40
Power load (kg/hp)	8.5
Speed at 0m	180km/h
Landing Speed	100km/h
Range	600km
Flight Endurance	4h
Ceiling (reached)	600m
Ceiling (expected)	3250m
Payload
Fuel	120kg

Light tailless pusher aircraft, powered by M-11 engine. Two-seater with enclosed cockpit was of wooden design. Conventional non-slatted ailerons covered outer 65% of the wing span, elevones - the rest. Wing endplates served as a tailplanes with rudders. KhAI-4 was the first in the USSR aircraft with tricycle landing gear, nosewheel was steerable.

Since aircraft was experimental, special attention was payed to main undercarriage. It had pneumatic wheels and hydraulically linked legs, capable to withstand serious shocks.

Aircraft was build in Summer 1934. Pilot B.N.Kudrin had serious complications while flying this unusual aircraft. First, KhAI-4 did not like to takeoff. Diving propeller momentum decreased the attack angle, while short lever of elevones made them inefficient. Only occasional bump on the runway made first flight possible. This happened on 180km/h run speed.

Handling of KhAI-4 was quite poor. Transversal reaction of the aircraft was delayed due to its large momentum. Endplates were out off propeller flow and proved to be very inefficient.

Large diving momentum from the high-placed propeller created serious climb problems. To compensate for this momentum, extensive deployment of elevones was needed. This in turn degraded wing lift - and aircraft started loosing altitude. Maximum obtained altitude was only 600m, reached with neutral stick position. Similar problems were with landing, w which could be performed only at small attack angle and high speed.

Undercarriage proved sturdy enough to withstand 'parachuting' from 1m altitude.

After third flight trial program was terminated: KhAI-4 was considered dangerous to fly. Nonetheless, ability of tailless aircraft to fly was proven, opening wide field of experimentation.

Predecessors	Modifications
None	Elements were used in KhAI-3 moto-glider

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References	Links
"History of aircraft construction in the USSR", Vol.2 p.120-121;	KhAI-4 (Slovak)