The Avro Lancaster and Boeing B-17 Flying Fortress were the two great heavy bombers of the Allied strategic bombing campaign — the Lancaster carrying the RAF's night offensive against German cities, the B-17 forming the backbone of the USAAF's daylight precision campaign. Both are now symbols of the bomber crews who suffered extraordinary losses in the skies over Europe.
Full guides: Avro Lancaster · Boeing B-17G Flying Fortress
| Avro Lancaster | Boeing B-17G Flying Fortress | |
|---|---|---|
| First flight | 1941 | 1943 |
| Origin | United Kingdom | United States |
| Length | 21.18 m | 22.8 m |
| Wingspan | 31.09 m | 31.6 m |
| Max speed | 450 km/h | 462 km/h |
The Lancaster and B-17 were designed around different strategic doctrines. The B-17 was built for daylight precision bombing: heavily armed with thirteen .50-calibre machine guns in power-operated turrets, flying in tight defensive formations that could create overlapping fields of fire against attacking fighters, and equipped with the Norden bombsight for precision targeting. The Lancaster was optimised for night area bombing of industrial cities: it carried fewer defensive guns (fewer, lighter .303-calibre weapons that were inadequate against German fighters), flew at night to avoid fighter interception, and was engineered around bomb capacity. The Lancaster's cavernous 33-foot bomb bay was the largest of any WWII bomber and could carry loads the B-17 could not physically accommodate — including the 12,000 lb Tallboy and 22,000 lb Grand Slam earthquake bombs used against hardened targets. The B-17 was more survivable in daylight conditions by design: its armament was formidable, and it could absorb enormous battle damage and still fly home. The Lancaster's defensive armament was frankly inadequate, and its night operations came at a terrible cost. Both aircraft were technically the same generation; they simply embodied different answers to the question of how to destroy Germany's industrial capacity.
Neither aircraft was designed for manoeuvring combat, but the B-17's heavier defensive armament made it the more dangerous target for a fighter attack. The B-17G carried thirteen .50-calibre M2 Browning machine guns covering most angles; the Lancaster's eight .303 Brownings in three turrets were effective only at very close range and could not damage most late-war German fighters beyond about 400 yards. German fighter pilots preferred attacking the Lancaster for this reason, and RAF night bomber losses reflected it: Bomber Command lost over 55,000 aircrew killed — a casualty rate approaching 50% of those who flew a full tour. The 8th Air Force's daylight losses were also catastrophic (particularly before long-range escort fighters arrived in 1944), but the B-17 formation's mutual fire support made isolated fighter attacks much more costly for the attacker. In a hypothetical direct contest at close range, the B-17's heavier guns and more comprehensive coverage gave it a clear defensive advantage.
The Lancaster is wider in the bomb bay but the aircraft are similar in overall size. The Lancaster's wingspan was 102 ft (31.1 m) versus the B-17G's 103.8 ft (31.6 m) — nearly identical. The Lancaster was heavier at maximum takeoff weight: around 68,000 lb versus the B-17G's 65,500 lb. Speed was also close: the Lancaster cruised at around 200 mph (322 km/h) and had a top speed of 282 mph (454 km/h); the B-17G had a similar cruise speed and topped out at around 287 mph (462 km/h). The key difference was payload: the Lancaster could carry up to 22,000 lb of bombs (with the Grand Slam), while the B-17G's bomb bay limited it to around 8,000 lb on long missions. The Lancaster's four Merlin engines gave it good high-altitude performance; the B-17 was optimised for the 25,000–30,000 ft band where the Norden bombsight worked best.
The Lancaster served almost exclusively with the British Commonwealth: RAF Bomber Command, the Royal Canadian Air Force, the Royal Australian Air Force, and smaller contingents from New Zealand, Poland, and other Allied nations. Post-war a small number served with the French Navy as maritime patrol aircraft. The B-17 was primarily an American aircraft (USAAF) but also served with the RAF in significant numbers in both the European and Pacific theatres. Post-war, B-17s were used by Israel (in the 1948 War of Independence, flying bombing missions from Czechoslovakia), Brazil, and several other nations. The B-17 also had a long post-war career as a search-and-rescue and weather reconnaissance platform with the USAF.
The B-17 flew first, in July 1935, against the Lancaster's January 1941 — a gap of five and a half years. The B-17's long development history meant it was already in limited USAAF service (and had been exported to the RAF) before America entered the war. The Lancaster, by contrast, was developed rapidly from the failed Manchester bomber (which suffered catastrophic engine problems) and entered service just as Bomber Command was restructuring its strategic doctrine under Arthur Harris. The Lancaster's late arrival but rapid production — over 7,300 built — gave Bomber Command the weapon it needed to prosecute the area bombing campaign at scale. The B-17's earlier development gave it time to accumulate combat lessons from the RAF and from early USAAF operations over Europe, leading to the definitive B-17G with chin turret and improved defensive coverage. Both aircraft evolved significantly in service; neither reached its final form until the war was well advanced.
Both types have surviving airworthy examples, but B-17s are more numerous. The most famous airworthy B-17 in Europe is Sally B, based at Duxford and the only airworthy example on the continent. In the United States, several B-17s are maintained in flying condition by organisations like the Experimental Aircraft Association and the Collings Foundation, appearing at airshows across the country. Airworthy Lancasters are extremely rare: there are only two in the world — one operated by the Canadian Warplane Heritage Museum in Hamilton, Ontario (FM213), and one operated by the BBMF at RAF Coningsby (PA474). The BBMF Lancaster is a summer airshow regular across the UK and is an extraordinary sight accompanied by a Spitfire and Hurricane. For the best chance of seeing both types in the air, Duxford's Flying Legends and RAF Waddington's airshows are strong choices.