Hi!
Some data about first serial heavy bomber IM:
Name: ILYA Muromec
name after ILYA Muromec , ancient hero.
Country: Russian Empire.
First sample: oct. 1913.
load: 1290 kg
Model:Series B (1914)
Maximum range: 650 verst :: 692.9 km
Power Plant: 4x140hp "Argus"
Wings Square: 152,6 m2
Test flights (one of a pilots is Igor Ivanovich Sikorsky(!))
Production: 6
Model:Series V (light) (1914-15)
Power Plant: 4x150hp RB3-6 , or 2x140hp+2x125hp Argus
Production: 22
Empty Weight: ~3000 kg
Max bomb load: ~500kg small bombs (one 410kg experiments)
Model:Series G(1915-1

Max height: 5200m (oxygen limit) with 1340kg load.
Speed: 137 km/h with 1900kg load.
Model:Series E(1916-17)
Power Plant: 4x220hp Renault
Empty Weight: 4960 kg
Bomb load: 800 kg
Defensive weapons: 8 machine-gun: 2x "Vikkers" with 1200-1500 ammo, 3x "Luis" w/ 940-1700ammo, 3x "Madsen" w/ 750-1000ammo
Production: ~80
pictures was scan from books.