of the aircraft to which they were attached. The Luftwaffe lost 77 aircraft in 1,200 of these sorties. Wright Field technical personnel reverse-engineered the V-1 from the remains of one that had failed to detonate in Britain and the Republic-Ford JB-2 was being delivered by early 1945. After the end of the war in Europe it was in consideration for use against Japan. General Hap Arnold of the United States Army Air Forces was concerned that this weapon could be built of steel and wood, in 2,000 man-hours and approximate cost of US$600 (in 1943). To put this in perspective, a single Boeing B-29 Superfortress airframe (based on program costs) cost about 126 times as much per ton of explosive delivered, not including the much higher costs for injured or killed aircrew, fuel, maintenance, bombs, ammunition, repairs, training and accidents, and despite being reusable, almost never accomplished enough missions to even approach covering just the production costs. Belgian attacks The attacks on Antwerp and Brussels began in October 1944, with the last V-1 launched against Antwerp on 30 March 1945. The shorter range improved the accuracy of the V-1 which was deviation per of flight, the flight level was also reduced to around . The Port of Antwerp was recognised by both the German and Allied high commands as a very important port. It was essential logistically for the further progression of Allied armies into Germany, although initially Montgomery had not given high priority to seizure of the Scheldt estuary giving access to the port. Countermeasures at Antwerp Both British (80 AA Brigade) and US Army anti-aircraft batteries (30th AAA Group) were sent to Antwerp together with a searchlight regiment. The zone of command under the 21st Army Group was called "Antwerp-X" and given the object of protecting an area with a radius of covering the city and dock area. Initially attacks came from the south-east, accordingly a screen of observers and searchlights was deployed along the attack azimuth, behind which were three rows of batteries with additional searchlights. US units deployed SCR-584 radar units controlling four 90mm guns per battery using an M9 director to electrically control the battery guns. Backup for the American guns was automatic 40mm batteries, which were not effective against V-1s. British gun batteries were each equipped with eight QF 3.7-inch AA gun (94mm) and two radar units, preferably the US SCR-584 with M9 director