Part of the Maywright war aircraft grade 1 — bundle 1, a series of aircraft reminiscent of the time between WWI and WWII. Detailed specifications in the comments.

During Zwartania's quick expansion during the humongous war the Zwartanian military wanted an airforce composed of planes that Zwartania's enemies could not even reach due to their sheer speed and climb rate. This led to the creation of the Ogromny Silnik, literally meaning "enormous engine."

Although the B-OS stroke a good balance between speed, bomb load, and ease of production, Zwartanian bombers were still not fast enough nor could fly high enough to get past thick anti-air-artry defensive lines unharmed, not while delivering a deccent bomb load too at least, and simply building more B-OS wouldn't cut it.

Since Zwartania already had more B-OS than it needed they could afford to divert Ogromny Silnik engine production to the creation of heavy triplane bombers equipped with not one but three OS engines, this new B-OS-3 was so fast and it had such a good climb rate it did not need a fighter escort at all, given that it took off far enough from enemy airfields as to gain a decent altitude on the way to its target.