The Mitrovich MMS-3

[dropcap]T[/dropcap]he years between WW I and WW II saw an explosion of various light transport aircraft with as final result in the thirties successful types like the Airspeed Courier, the Miles light aircraft series and of course types like the Beech Staggerwing. Many countries were active in the design, development and construction of such light planes for transport of 2-4 people but only a limited number of these types would become well known. This is one of the lesser known types, built in Yugoslavia: the Mitrovich MMS-3.

The MMS-3 was a design from Ing. Mitrovich for a twin-engine monoplane with a high shoulder wing without further struts. It was of mixed construction and was built for the Yugoslavian airline company ‘Aeroput’. It featured twin tailbooms connected by a horizontal tailplane and a short fuselage section. The two non-retractable main wheels were placed just after the engines in front of the tailbooms. They were connected to the fuselage by a V-shaped oleo-pneumatic shock absorber. A small tailwheel was placed at the extreme end of the fuselage. For use from simple grass strips low pressure tyres were fitted.

The wooden wing consisted of a double box-shaped wing-spar with a leading edge covered with birch wood. Rest of the wing was covered with plywood covered with doped fabric. The fuselage section including the pilot /passenger cabin had a rounded well streamlined nose and ended at the rear with a small conical tail section. The fuselage had inside three seats placed on a row with two doors on each side that could be opened upwards. The elevator at the tail was fitted with small so-called ‘Flettner’-flaps. The single vertical tail was centrally placed on the horizontal tail section. All fuel was housed in two fuel tanks in the central wing section with a total capacity of 265 litres. The flight characteristics were very good and safe. At loss of speed and power, the plane would automatically enter into a glide flight without stalling. Also on a single engine power, normal curves could be made.

Only one prototype was built.

Technical details:
Engine: two Pobjoy Niagara 7-cilinder air cooled radial engines of 90 hp each
Dimensions:
-wing span 11.60 m
-length 7.40 m
-wing area 16.00 m2
Weights:
-empty 600 kg
-loaded 1000 kg max.
Performances:
-maximum speed 235 km/h
-cruising speed 213 km/h
-landing speed 75 km/h
-climb to 5000 m in 22 min.
-service ceiling 6000m (1800 m on single engine)
-range not given, but flight duration with 3 persons was 3 hours and with 2 persons 5 hours

Nico Braas

Source: Luftsport no. 9, 29 April 1936, p.182-183