1 Background Data: Strategic Air Offensive vs. Germany Randy H. Katz CS Division, EECS Dept. University of California, Berkeley Spring 2009 U.S. vs. British Viewpoints • Goal: “destruction and dislocation of the Germany military, industrial, and economic system and the undermining of the morale of the German people to the point where their capacity for armed resistance is fatally weakened” – U.S.: Accurate (daylight) bombing of strategic industries and services to disable Germany’s war economy – Britain: City area (night) attacks to undermine the German people’s will to fight2 Questions for Discussion: Allied Offense • What to bomb, and what is it worth? • Military technology - what is the most effective kind of bomb? • How to find targets? • How to get home safely? • In retrospect, what was effective? Heavy Bomber Range3 Strategic Targets • Strategic Air Offensive – US 8th Air Force • 333,000 sorties • 5500 losses (1.6% loss rate) • 622,000 tons of bombs – Britain Bomber Command • 374,000 sorties • 10,000 losses (2.7% loss rate) • 955,000 tons of bombs Strategic Targets • Target Type – Military – Transportation – Industrial – Petrochemicals – Others?4 Bomb Types Anti-personal Anti-tank Hardened Targets “Soft” Targets Explode on contact vs. Penetrate and then explode Round 1: Target Planning • RAF: Area/City Bombing • USAAF: Precision Strategic Bombing5 German Radio Navigation Knickebein German Radio Navigation X-Gerät6 German Radio Navigation Y-Gerät British Counter Measures • Jamming • Beam Bending7 Radio Navigation British Approach—Gee • 3 xmiters: Master, A, B – START: Master emits pulse – 1 ms: Slave A emits pulse – 2 ms: Master emits double sync pulse – 3 ms: Slave B emits pulse – Repeats every 4 ms/250 per s • Difference in time between master and slaves defines a unique point where two hyperbolas intersect • Limited precision because of difficulty in sync’ing slaves with master Radio Navigation: British Approach--Oboe • Many stations placed around England • Any can be a Cat or Mouse • Very accurate! 110m @400km • Used by Pathfinders to mark targets8 Formation Defense MGs and Mutual Support Formation Defense9 Video Interlude • Bomber Tactics10 Bomb Effects Cologne After 1000 bomber raid 1942 Bomb Effects Dortmund 194511 Bomb Effects Hamburg, after a shattering assault in 1943: 40, 000 dead and 70 % of the city destroyed Bomb Effects Peenemunde before and after concentrated attack, 1943. 44 aircraft lost. The first V2 fell on London in 1944.!12 Bomb Effects Phillips factory, Eindhoven, 1942, attacked by 93 aircraft. 148 civilians killed, production stopped for 6 months Bomb Effects Mohne dam after raid by highly trained crews, at night. 8 of 18 planes failed to return.13 Bomb Effects Bomb Effects Lancaster and Grand Slam Bomb (22,000 lbs.)14 Challenge of Precision Bombing Le Havre, 1944 Challenge of Precision Bombing Emmerich, 194315 Paulliac, 1944, target markers have just been released Paulliac, 1944, 5 minutes later16 Cap Griz Nez 1944 Target indicators bursting over Frankfurt, 1944, laid by Pathfinders17 Night Photography Night Photography Fires and Searchlights Ruin Photos18 Ground Radar H2S view of the Zuider Zee dam Ground Radar Map and H2S view of Oslo Fjord, 1943, during an anti-shipping strike19 Bomber Vulnerability Heavy bomber hit by flak at 45000 feet Round 2: Allied Technology Development20 Questions for Discussion: German Defense • How to make bombing more expensive – by destroying bombers – by leading bombers off target • How to detect incoming raids? • How to coordinate response to incoming raids? • How to engage bombers at night? German Radars • Higher frequencies/shorter wavelengths than comparable British radars • Ability to tilt and rotate • For coast and inland defense • 100 km range at 10,000 feet21 German Radars • Wurzburg tracking radars – Elevation and azimuth easily positioned • 25 km range German Night Fighter Airborne Radar22 Night Fighter Defense • No effective night escorts until late in the war • Surface radars & human controllers vector night fighters to bombers • Bombers illuminated by searchlights makes them visible • Nightfighters attack from below and behind, very difficult to see • Affects the targets in the end: destroy the German airforce! Round 3: German Response23 Defensive Technologies and Response • Searchlights • AA Guns • Proximity Fuze • Airborne Radars for interception • Fly high • Fly high • Window/Chaff • Window/Chaff Offensive Technologies and Response • Longer range, heavier bombers • Longer range escorts with drop tanks • Surface radars for night target identification • Gyrostabilized bomb sights • Guided bombs • Better interceptors (Jet and Rocket Fighters) • Jamming • Distribute production24 Measure-Counter Measure-Counter-Counter Measure • “The atom bomb ended the war, but radar won it.” – Radar-Jamming-Higher Frequency or Frequency Agile Radar – Radar-Window-Doppler Radar that discriminates between slow moving strips of metal and airplanes – Beam Radio Navigation-Jamming or Beam Bending-Alternative Non-Beam Navigation Approaches U.S. Strategic Bombing Survey • http://www.anesi.com/ussbs02.htm – “The city attacks of the RAF prior to the autumn of 1944, did not substantially affect the course of German war production. German war production as a whole continued to increase.” – “The city area raids have left their mark on the German people. Far more than any other military action … these attacks left the German people with a solid lesson in the disadvantages of war. It was a terrible lesson; conceivably that lesson, both in Germany and abroad, could be the most lasting single effect of the air war.”25 U.S. Strategic Bombing Survey – “Conventionally the air forces designated as "the target area" a circle having a radius of 1000 feet around the aiming point of attack. While accuracy improved during the war, Survey studies show that, in the over-all, only about 20% of the bombs aimed at precision targets fell within this target area.” – Schweinfurt Raids: Massed