Sikorsky Ilya Mourometz
The worlds first 4-engined aeroplane, Russkii Baltiski was designed and flew in 1913. From this was developed the Ilya Mourometz flown early in 1914 and was capable of carrying 16 passengers to an altitude of 2000m, at a speed of 62mph and able to remain airborne for 5 hours. Ten examples were ordered for the Imperial Russian Air Service at the outbreak of war and, eventually 80 aircraft were built. The first operational sortie was made on 15th February 1915 over East Prussia and, up to the time of the Russian Revolution of 1917, some 400 bombing raids were made over German and Lithuanian territory for the loss in action of only one aircraft.
Before the days of the introduction of interrupter mechanism for Allied fighter aeroplanes to enable a machine gun to be fired between the revolving blades of the propeller., British and French designers chose to develop aircraft with pusher engines armed with a machine gun which could be operated from the front cockpit by either the pilot or the gunner. An interim solution which used the more efficient tractor biplane was the complicated SPAD A2 with a pointed front nacelle placed directly ahead of the of the propeller containing a gunner and Lewis Gun. The pilot sat in a cramped cockpit behind the propeller. Designed by M. Bechereau of the Societe pour les Appareils Deperdussin the aeroplane first flew on 21st May 1915 powered by an 80hp Le Rhone 9c. 96 SPAD A2’s were constructed; 42 for the French Aviation Militaire and 57 for the Imperial Russian Airforce, now engined with the 110hp Le Rhone 9j. The A2’s operational life with the French was brief as faster and lighter aircraft were now coming into service equipped with guns firing through the propeller. The Russian Air Force with a general shortage of equipment retained the SPAD A2 much longer and used it with limited success in most battle areas.