Amongst all US bombers delivered to Soviets,
the Soviets flyers really loved A-20 Havoc which was called according to Brits
designation Boston.
http://en.wikipedia.org/wiki/A-20_Havoc
They would use it mainly as a torpedo bomber for which purpose they would
make it carry tree torpedos.
As far I know Soviets really liked Bostons which they were using in greater number
then Americans. And they would continue fly it up to early 50s.
That was truly a great plane.
Thank you.