World War Two:
Why was accurate bombing so difficult?
One of the good things about teaching History is that you’re constantly learning new things (when did Maths teachers last get excited about a new times table?) or coming across things you’ve never thought closely about and discovering there’s more to a topic than you thought. This activity by Ian Luff is one of those thought-provoking activities – growing up in the 50s and 60s I knew about Lancaster bombers and the Dambusters but what thoughts I had were about the courage needed to take part in raids. Never did it cross my mind just how difficult it was to get a bomb anywhere near a target and what the implications of this were for bombing strategy – that the difficulty of precision bombing were, in part, a cause of the carpet bombing of cities and domestic targets. So, not only is this a good activity for explaining why accurate bombing was difficult in World War Two I feel I’ve learned something new too.
So here’s Ian’s description:
From 1939 until late 1942 Britain depended almost entirely on the RAF to carry out offensive action against Germany. Its chosen method of attack, night time bombing raids, remained a key part of British strategy until the very end of the war. Controversially, the priority targets for these British raids were the cities of Germany.
Night raids had been chosen by the British in an attempt to cut the frightening losses among bomber crews resulting from similar raids in daylight. Particularly at night, even with increasingly sophisticated electronic navigational aids, it proved impossible to move away from what became known as ‘area’ or ‘carpet’ bombing: the indiscriminate targeting of vast areas of civilian housing. This was later rationalised as an attempt to hit German industry by de-housing and killing its workers but in fact cities were chosen as targets because, quite simply, British - and anybody else’s - bombing lacked the accuracy to hit any other kind of target at night. The choice for the British was either to bomb cities or not to bomb at all.
This activity will help students to understand why precision bombing was so difficult. It can stand alone as a catalyst for class discussion or can be used with the activities on pages 78 and 84-87 of the ‘SHP History Year 9’ pupil book. The demonstration’s graphic illustration of the difficulty of accurate bombing gives access to the technical explanations below, reinforces the understanding of the activities and enriches resulting follow up discussion about the morality of targeting civilians in their homes.
Why was night bombing and even, to a lesser extent, daylight bombing in the Second World War so frequently inaccurate? In December 1941 it was estimated that only three in every hundred British bombs dropped at night came within five miles of the intended target. This was understandable early in the war as young navigators struggled to find blacked out cities through manual methods. But by 1942 the electronic device known as ‘G’ had made it possible for bombers to find cities, and even specific features of cities, in the dark; it still however proved impossible to consistently hit anything more precise than whole areas of those cities. Why was this the case? Why was it so difficult to bomb accurately even when the target had been found and identified?
Essentially several factors combined to make it extremely difficult to hit a target:
• Bombs released from an aircraft continued to move forward at the speed of the aircraft: approximately 280 miles per hour. The bombs would of course slow in forward motion as they fell but this rate of slowing was not consistent owing to atmospheric conditions varying the density and therefore drag of the air. This forward motion and inconsistent rate of slowing made it very difficult for a bombardier to judge the optimum release point for his bombs. Poor visibility by night of course compounded the difficulty of judging the best release point.
• Cloud cover frequently obscured the target
• Aircraft bombed from approximately 14 000 feet (or three miles) high. Falling bombs were therefore subjected to buffeting by winds and air currents for a long period as they fell. In the 1940s there was no accurate way for a bomber to measure wind speed over the target. Primitive analogue computer bomb sights, such as the ‘Norden’ carried by US bombers, had no way of overcoming this problem
• Even if they failed to shoot an aircraft down, exploding anti aircraft shells fired from the ground would frequently throw an aircraft off course during its final bomb run.
• One screwed up paper towel per pupil.
• One sheet of A4 paper as a target
• One hairdryer or sheet of sugar paper
1. Arrange the desks in your classroom in 3 rows facing the board, as shown on the Room Plan. There should now be two aisles between the three rows
2. Place the A4 sheet on a clear area of the classroom floor at the front of the room opposite one aisle between a row of desks. Explain that this represents the specific target area for the raid.
3. Line up the class down the aisle opposite the target. Each pupil holds arms out and clutches a screwed up paper towel in one hand.
4. Explain to the pupils that their objective will be to drop their ‘bomb’ (paper towel) onto the target. They must drop by opening a hand and allowing the bomb to fall and must remain moving whilst they do so. Emphasise they must drop not throw the bomb.
[In fact, if they're to have a chance of hitting the target, they need to release early, before they are ‘over the target’ to allow for their own forward motion. If dropped rather than thrown their paper bomb will continue to move forward much as a real bomb would have done. I don't tell the class this. The point is that some will work it out for themselves, some will not.]
5. On the command ‘move ‘ pupils walk briskly forward one by one - just as British bombers approached the target one by one. They release their bomb, turn sharp right after release and head back down the second aisle.
6. As the pupils drop their loads record the number of bombs that actually hit the target. Work this out as a percentage. The accuracy of aim of my classes has varied but they generally record around 30% accuracy – it’s surprisingly difficult without practice – and that’s before you start up the hairdryer!
7. Now try the exercise again with the hair dryer (on low speed) blowing air over the target (which will now need to be secured to the floor by tape or blu tac) or, if lacking a hairdryer flap a piece of sugar paper to crate a draught. If you feel brave try it with the blinds almost completely drawn and lights out to simulate a night raid (but be absolutely sure that no potential tripping hazards remain on the floor). Again work out percentage accuracy under these new conditions - it’s far harder!
8. Explain to pupils that they have been bombing from a height of less than one metre at a speed of three mph. Real aircraft were bombing from over 4000 metres at 280 mph!
9. Discuss percentage accuracy achieved under each set of conditions. Compare to real statistics - in fact just under 50% of US bombs dropped under perfect daylight practice conditions came within a quarter mile of the intended target. Under even daylight operational conditions less than 10% came within that distance.