B-40

[Babalonian]

OK, I'll bite: why does taking out the heavy bombs and adding a few light guns (and light gunners) make a plane much slower?  Extra drag from extra turrets??

You got it, it's the difference between rolling a 5lb-porcupine or 5lb-armadillo down a leaf-covered hill.

[Pigslilspaz]

You got it, it's the difference between rolling a 5lb-porcupine or 5lb-armadillo down a leaf-covered hill.

Get the best of both worlds and roll a hedgehog

[Butcher]

OK, I'll bite: why does taking out the heavy bombs and adding a few light guns (and light gunners) make a plane much slower?  Extra drag from extra turrets??

Normal B-17 carried some 2500 rounds of ammo, B-40 carried like 10,500 rounds of ammo, plus the turrets themselves - a fully loaded YB-40 was like 4,000lbs heavier then a normal B-17.

Drag + overweight = slow.

[MiloMorai]

B-17G

Empty weight: 36,135 lb (16,391 kg)
Loaded weight: 54,000 lb (24,500 kg)
Max. takeoff weight: 65,500 lb (29,700 kg)
Service ceiling: 35,600 ft (10,850 m)

YB-40

Empty weight: 54,900 lb (24,900 kg)
Loaded weight: 63,500 lb (28,800 kg)
Max. takeoff weight: 74,000 lb (34,000 kg)
Service ceiling: 29,200 ft (8,900 m)

Armament

Guns: 18 (or more) × .50 in (12.7 mm) Browning M2 machine guns. Typically used 14-16.

Location    Rounds
Nose    2,200
Front top turret    2,500
Aft top turret    3,300
Ball turret    300
Waist guns    1,200
Tail guns    1,200
Total    10,700