21/08/2021
The next aircraft built by Kalinin’s DB in 1927 and named K-3, was destined to become the first air ambulance in the history of Soviet aviation.
The direct development of the project was led by A. N. Gratsyansky, who kept constant contact with physician specialists. Requirements for the future aircraft were strict: ensuring urgent medical care to patients and seriously wounded directly at the place of their stay with further transportation to the nearest treatment point.
What do you need to create a sanitary aircraft? The need for it always arises unexpectedly - hence the need for constant readiness to flight. The urgency of medical care dictates the need to land in close proximity to the patient or wounded, most likely on unprepared sites, which imposes large limitations on the landing speed, run-off and roll-out, as well as the strength of the chassis. Also the heavy condition of patients transported by the aircraft assumed the creation of some comfort to accommodate them with the possibility of providing the necessary medical care directly in flight.
Already at the stage of the sketch design it became clear that the operating opportunities laid down in the design of the serial aircraft, satisfy demanding physicians. But with the layout of the sanitary compartment, the cabin had to be renewed. Where and how to enter stretchers? Where to attach them in flight? How to place a doctor and accommodate medical equipment? Several options were considered young engineers, but there was no acceptable solution. One morning - recalls A. N. Gratsyansky I hurried to Kalinin: so big was the desire to show another option. I offered to lengthen the door to the salon in the horizontal direction and lay in the tail part of the fuselage. And the stretcher is fixed to special suspensions, designed by doctor Lingart - Senior Doctor of the Naval Sanitary Service of the Red Army ... Kalinin looked, thought for a couple of minutes and pronounced: “Well…It looks like what we need”.
After a month, in June 1927, the representatives of the Red Cross and the military-sanitary department considered and approved the completed project of the K-3 aircraft. It received a traditional high elliptical wooden wing (light, durable and very convenient when repairing) and steel fuselage. The dimensions and external outlines of the sanitary machine were the same as in the head model K-2, although the structure became 80 kg lighter. This made it possible to increase the payload of the aircraft and significantly improve its rate of climb.
The spacious and light cabin, in addition to the pilot and flight mechanic accommodated stretchers installed in two tiers and one doctor. The stretchers with patients were fed into the sanitary compartment through a long rectangular hatch in the left side of the fuselage, and then fastened. The doctor was located in the legs of the patient on a comfortable folding chair. Behind his back there was a locker with medicines and a balloon with air. In the corner were located tanks with cold and hot water and drain sink. The heated walls of the cabin were trimmed with warm sound-absorbing felt. The cabin itself was ventilated by two fans, and in the passage there were electrical lamps for lighting. The floor and all the devices of the sanitary compartment allowed regular cleaning and disinfection. Useful load at four-hour fuel reserves was 340 kg.
In early December 1927, the sanitary aircraft set on the skis arrived to Moscow. At the central airfield, the plane made several flights with representatives of sanitary services, demonstrating a light takeoff and landing, excellent stability and control in flight. Special admiration caused a sanitary compartment. “K-3, - wrote ‘Aviation and Chemistry’ magazine - is a big victory of Soviet aviation equipment.” The tests at Air Force Research Institute proved high quality of the machine. K-3 with full load developed the average flight speed of over 150 km / h and, which was very important, showed the estimated take-off and landing characteristics. On March 4, 1928, the K-3 was solemnly transferred to the representatives of the air fleet at the Central Airfield in Moscow. The airplane was assigned the number POKK-1. In 1928-1930, it has taken to hospitals from hard-to-reach areas 30 people. At those times it was regarded as a great achievement. Why there was no serial production of such a useful aircraft, we can only guess now.
