AVRO Manchester rear turret

Been breaking my head over this one for a while :confused:. I had always assumed that the Manchester was only ever equipped with the FN4 tail turret – photos abound, easily distinguishable by the two horizontal “glazing bars” on the sides of the turret.

I recently acquired a CD copy of AP1600A which is the maintenance manual for the Manchester. This confirms the aircraft was equipped with the FN4 but also states :

“At the end of the main floor on both sides of the fuselage are mounted the ammunition boxes for the rear turret, the ammunition being fed through ducts running along the wall of the compartment.”

And :

“A rotating gun turret (type FN4) is provided at the rear end of the fuselage. The spare ammunition for this turret is supplied by means of ducts from the boxes on each side of the fuselage at the rear end of the main floor.”

And :

“The rear turret is supplied with ammunition by means of four ammunition boxes and ducts … In the case of a turret fitted with servo feed, the ducts run under the turret. If a turret without servo feed is fitted, the ducts curve upwards to a vertical position between formers 40 and 41.”

The manual then actually illustrates these boxes and ducts.

To my knowledge however the FN4A was never equipped with a servo feed, the guns being fed by 4 x 1000 round containers inside the turret. This unlike this turret’s successor the FN20 which did have servo feed.

So, my question, was the Manchester ever operationally equipped with the FN20 like the Lancaster? And what is the point of having that spare ammo in fuselage boxes and ducts when carrying an FN4? Armourers didn’t have an easy time filling the FN4’s ammo boxes when on the ground and I can’t imagine a fully kitted out air gunner pulling the belts out of those ducts and then loading them in the turret’s containers in flight!

In Robert Kirby’s “AVRO Manchester – The Legend behind the Lancaster” mention is made of wind tunnel tests of a Manchester fuselage with an FN20 but no operational use is being referred to.

Your thoughts and comments would be most welcome.

Cheers,

Walter