You guys seen this one --> YB-40

[mussie]

YB-40 Flying Fortress Heavy Escort

The aircraft differed from the standard B-17 in that a second dorsal turret was installed between the top turret and the waist guns; and the single 0.50-calibre (12.7 mm) machine gun at each waist station was replaced by a pair of 0.5-calibre (12.7 mm) guns. In addition, the bombardier's equipment was replaced with two 0.50-calibre (12.7 mm) machine guns in a 'chin' turret to augment the existing 'cheek' machine guns, and the bomb bay itself was converted to a magazine.

The concept was twofold. First, the YB-40 would provide a heavily-gunned escort capable of accompanying the bombers all the way to the target and back.

Second, they were used as decoys; a YB-40 would leave the bomber stream with one engine feathered, apparently in distress. Enemy fighters would close for the kill and discover that the 'cripple' was nothing of the kind.

The aircraft was used with some success in the Mediterranean Theater of Operations, but was overall a failure because it could not keep up with standard B-17Fs once they had dropped bombs. It was withdrawn from service after less than ten missions. Some 25 were built. Operational units were stationed with the 92nd Bomb Group (H) at their base in Poddington, England.

http://www.327th.org/327th-org/Greg/yb-40.htm
http://www.answers.com/topic/yb-40-flying-fortress

It was a failed project but never the less pretty cool IMHO

Later

[RTSigma]

Twin .50's and a few extra gun positions?

Sounds like a battleship B-17 that'd be great for ground support if there was no AA around.

[MiloMorai]

There was also a B-24 gunship, the XB-41.

[tonyki61]

theydidn't get past x stage as it was to slow and heavy.
It didn't carry any bombs.Was meant to be gunship escort,but when the rest of the bombers dropped their ord this one could not keep up.So they didn't persue it.

[Sikboy]

It only had 4 extra .50s? What the hell made it weigh so much? all the Ammo?

Seems like a long run for a short slide. Now, if they started putting in 20mms ....

-Sik

[Kweassa]

I think it had more to do with out-dated mode of thinking rather than technical difficulties. If they really thought it was a good idea, I'm sure they would have come up with some solutions, which, they didn't.

[J_A_B]

WW2 bomber mounted machine guns didn't really shoot down huge numbers of fighters.  They provided defence to the bombers by forcing the enemy fighters to stay farther away and make faster less accurate passes, not necessarily by shooting down the fighters.

Thus, the YB-40 wouldn't have accomplished anything that the gunners on the normal B-17's couldn't do.

J_A_B

[john9001]

deathstar

[mussie]

The YB-40 introduced the chin turret to the B17 And they did try 20 and 30 mm cannons but I don't think they were ever used in combat.

The bomb bay was used as a magazine so I guess that would be a hell of a lot of 50 cal.

Personally I think the 17 was a hell of a plane

I have a photo of one that was hit by a 109 and when I say hit I mean it collided with it. there is a gaping hole from the top of the fuselage (above the side gunners) to the middle of the vertical stabilisers. and I am pretty sure it landed. now that's a tough plane.

As for the YB-40, like I said it was a failed project but I still think it was pretty dam cool
 

[MiloMorai]

and the other a/c

[mussie]

From the photo above it looks as if the ball turret could not fire parallel to the aircrafts fuselage

The base of the barrels would have been in the way

Interesting

[SunTracker]

Mussie, that picture is just showing the ball turret in its retracted position.  It could be lowered in flight.

[mussie]

I thought that might be the case