Found this looking lonely in an antique shop today. I know what it is in that is says it is a bombing angle computor but that does not enlighten me much (flying clothing being more my area to collect). What is it for, how does it work and how old is it? I assume wartime in that it is marked in MPH although it can be flipped for Knots. Thanks for any help.
By: austernj673 - 10th May 2013 at 18:43
It’s a manual computer for use with the Mark 14 wartime bombsight as fitted to British heavy bombers. Without digging the books out i think it was located on the Lancaster in a small slot underneath the Bomb aimers kneeling cushion so that it could be used in an emergency if the main bomb computer packed up.
There are quite a few of these about and maybe ‘Air Ministry’ might be able to add some more information but my gut feeling is that these maybe early post war issue as the AM stamp has been replaced by the Crowsfoot.
By: TonyT - 10th May 2013 at 17:55
I would say you get your altitude from the altimeter, dial in your ground speed, run round the dial until you find the two that align the closest, in your case 2000ft at 135 MPH, you then read off the bombing angle on the bottom scale, dial that into the bomb site and that will move the crosshairs fwd or aft to that angle… Zero being vertical, so when you look through the sight it is actually looking forward at an angle instead of looking vertically down, so when you drop the bombs, their fwd speed will form an arc as they decend and hit the target, the same as if you were parked directly overhead and dropping vertically at zero degrees… It’s simply compensating for height and speed…
The rectified airspeed is the altitude compensated airspeed over the ground, think of a push bike wheel, the centre hub moves an inch in distance but the tyre has to move as an example 4 inches through the air to cover the same distance and will travel faster than the hub to do it, same with an aircraft at height above the earth, so the above in paragraph one is calculating that.
Well that’s my best guess 🙂
Sign In
May 10, 2013 at 5:37 pm