[Oleg Maddox]

Originally Posted by Romanator21

It's a small tank, and the turret was removed to save weight - it would have been operationally useless, and that's one reason why the project was abandoned.

http://en.wikipedia.org/wiki/Antonov_A-40

There is repeatable mistake in description
It was tested with the turret (gun), but without shells inside and half of fuel load to save weigh for the trials and to make it easy take off for the first ever use.
It was found that Soviet VVS have not free and prepared for this purpose aircraft to tug this system without problems of too much using fuel withe small speed and on enough high altitude (but not over the top of the forest). There was experiment with two tanks onboard under TB-3... so..... which is more worse from aerodynamics point of view.
Another and real problem of this project was other: even it was successfully tested for smooth and easy gliding... there was anyway problem in education of the crew to fly in additional to normal driving on the ground and battle.
This problem stopped this project, but not the tug plane in reality.

Simply autors repeating one post soviet time book, where not all descriptions was present in a correct way from technical point of view.