awesome guys... thanks for the info... I'll be pulling a couple of these tonight.
I would recommend you don't waist your time... here's why. It takes 38K of ords the destroy HQ (square large building). Unfortunately HQ is no longer susceptible to blast damage like a town building or a hanger. That was changed a number of years ago.
What you'll find is your drone bombers will not actually hit the HQ. Their bombs fall either side of it. Only the lead bomber actually hits the target. Even with a full salvo and a delay of 0.05 you'll not put enough ords down.
"Ah! but I'll make another run" I hear you say. Well here's the news. HQ regains in time. The damage isn't long lasting so by the time you get back to the HQ for another drop it's fully regained from previous damage. Your repeating the same run for no effect. Essentially do absolutely nothing repeatedly.
To destroy HQ with high altitude bombers you'll need, as a beginner, three sets of Lancaster's or five sets B24's/B17's. Unfortunately you and your buddies will kick up a huge dar bar alerting the enemy. The size of the dar bar can be reduced by fly a very close formations of 300ft or less but it will still be a significant dar bar.
Another down side to bombing HQ is it only takes 8 boxes of supply to fully rebuild HQ. This is made very easy to do if a vehicles can spawn to HQ. None the less C47's can do the job before you get even a quarter of the way home.
I would not recommend bombing an enemy HQ until you have captured bases close by and can destroy enemy barracks to stop the resupply of HQ.
That said it can be fun to mount a long range multiple bomber run....good luck and watch out for ME163's.