Had Thiel remained alive, development of a simplified 25 tonne thrust engine for the V-2 probably would have been completed in time for production versions of the missile.
The next step was to make a 4.5 tonne thrust by clustering three of the 1.5 tonne engines as preburners. However Thiel still had burn-throughs in test runs. Poehlmann suggested the use of film cooling, which finally solved the problem. For the 25 tonne thrust engine, Thiel simply used 18 x 1.5 tonne thrust chambers, feeding a common mixing chamber. This was on the test stand in early 1939.
With the V-2 development program already in crisis, the Allies launch a massive bombing raid against Peenemuende. On that evening test pilot Hanna Reitsch was visiting the launch site. At 23:30 the air raid siren sounded. 600 British bombers drop 1500 tonnes of ordnance on the launch centre. However many bombs fell in the ocean around the peninsula, or buried themselves harmlessly in sand dunes. The resident area was hardest hit, while the Luftwaffe station at Peenemuende West was not touched. 47 British bombers were shot down - they were told before the raid that this was the most important mission of the war, and that their commanders would accept a 50% loss rate. 735 people were killed in the raid on the ground, including 178 of the 4000 inhabitants of the residential area. A large number of the foreign slave workers in the Trassenheide concentration camp barracks were also killed.
After the tremendous raid the rocket team wander around the devastated facility, half-clothed, the buildings bathed in a weird light and everything covered in fine sand, as if flour was dropped over everything. Thiel and Walther - the two leading rocket engineers in Germany - were killed in the raid, and virtually all major facilities were damaged. The saving grace was that the soft sand of Peenemuende attenuated the blast of many bombs. Nine bombs hit the main assembly hall, but while there was splinter damage to some of the machine tools, there was no decisive hit that would prevent production from continuing. It was estimated that operations could resume in 4 to 6 weeks.
The raid was not unexpected. The high altitude contrails of the V-2 test launches were called 'frozen lightning' and could be seen from Sweden on clear days. The location and purpose of Peenemuende appeared in a crossword puzzle in a illustrated magazine published in central Germany in early 1943. British reconnaissance flights to locate the launch facilities had been recognised for what they were.
This raid, together with the bombing of V-2 production lines at the Zeppelinwerke in Friedrichshafen and the Raxwerke in Wiener Neustadt convinced Saur to reduce the V-2 production rate goal to 900 per month.