In June 1935 and February 1936, Dr. Eugen Sänger published articles in the Austrian aviation publication Flug on rocket-powered aircraft. This led to his being asked by the German High Command to build a secret aerospace research institute in Trauen to research and build his "Silverbird", a manned, winged vehicle that could reach orbit. Dr. Sänger had been working on this concept for several years, and in fact he had began developing liquid-fuel rocket engines. From 1930 to 1935, he had perfected (through countless static tests) a 'regeneratively cooled' liquid-fueled rocket engine that was cooled by its own fuel, which circulated around the combustion chamber. This engine produced an astounding 3048 meters/second (10000 feet/second) exhaust velocity, as compared to the later V-2 rocket's 2000 meters/second (6560 feet/second). Dr. Sänger, along with his staff, continued work at Trauen on the "Silverbird" under the Amerika Bomber program.
          The Sänger Amerika Bomber (or Orbital Bomber, Antipodal Bomber or Atmosphere Skipper) was designed for supersonic, stratospheric flight (please see diagram below). The fuselage was flattened, which helped create lift and the wings were short and wedge shaped. There was a horizontal tail surface located at the extreme aft end of the fuselage, which had a small fin on each end. The fuel was carried in two large tanks, one on each side of the fuselage, running from the wings aft. Oxygen tanks were located one on each side of the fuselage, located forward of the wings. There was a huge rocket engine of 100 tons thrust mounted in the fuselage rear, and was flanked by two auxiliary rocket engines. The pilot sat in a pressurized cockpit in the forward fuselage, and a tricycle undercarriage was fitted for a gliding landing. A central bomb bay held one 3629 kg (8000 lb) free-falling bomb, and no defensive armament was fitted. The empty weight was to be approximately 9979 kg (22000 lbs).
          An interesting flight profile was envisioned for the "Silverbird". It was to be propelled down a 3 km (1.9 mile) long monorail track by a rocket-powered sled that developed a 600 ton thrust for 11 seconds (please see diagram below). After taking off at a 30 degree angle and reaching an altitude of 1.5 km (5100'), a speed of 1850 km/h (1149 mph) would be reached. At this point, the main rocket engine would be fired for 8 minutes and burn 90 tons of fuel to propel the "Silverbird" to a maximum speed of 22100 km/h (13724 mph) and an altitude of over 145 km (90 miles), although some sources list the maximum altitude reached as 280 km (174 miles). As the aircraft accelerated and descended under the pull of gravity, it would then hit the denser air at about 40 km (25 miles) and 'skip' back up as a stone does when skipped along water (please see drawing below). This also had the added benefit of cooling the aircraft after the intense frictional heating encountered when the denser air was reached. The skips would gradually be decreased until the aircraft would glide back to a normal landing using its conventional tricycle landing gear, after covering approximately 23500 km (14594 miles).
         The final test facilities for full-scale rocket engine tests were being built when Russia was invaded in June 1941. All futuristic programs were canceled due to the need to concentrate on proven designs. Dr. Sänger went on to work on ramjet designs for the DFS (German Research Institute for Gliding), and helped to design the Skoda-Kauba Sk P.14. Although the Luftwaffe did its best to stop Dr. Sänger from publishing his research results, a few copies went unaccounted for and made their way to other countries. After the war, he was asked to work (along with mathematician Irene Bredt) for the French Air Ministry, where in a bizarre plot, he was almost kidnapped by Stalin, who recognized the value of the Amerika Bomber.
Model photo of the Sänger Amerika Bomber 
over New York City
Model photo of the Sänger Amerika Bomber 
over Chicago

     View Josha Hildwine's Sänger "Silverbird" Orbital Bomber LuftArt images

              Span: 15.0 m (49' 2")               Length: 27.98 m (91' 10")               Max. Speed: 22100 km/h (13724 mph)

1) Pressurized Cockpit     2) Oxidant Tanks     3) Fuel Tanks    4) High-Pressure Combustion Chamber of 100 Tons Thrust
5) Auxiliary Rocket Chambers     6) Wedge-Shaped Wing     7) Retracted Undercarriage   8) Free-Falling Bomb

1) Captive Rocket Booster of 600 Tons Thrust   2) Sänger Amerika Bomber of 100 Tons Thrust
3) 3 Km (1.9 miles) Long Monorail Track    4) Sled Carriage


 The diagram on the right is part of Dr. Eugen Sänger's original proposal and shows the expected flight path that his "Silverbird" would travel on a bomb run to New York City. Please note the skipping, roller coaster-like path the Sänger would take before landing....
        Another sketch of the Sänger on its launching rail 
           1) Launch Rail     2) Sänger Amerika Bomber 
           3) Launching Sled     4) Rocket Booster
Dr. Eugen Sänger confers with mathematician 
and future wife  Irene Bredt in their WWII 
research lab in Trauen.


    A wind tunnel model of the Sänger Amerika Bomber, which is still in existence today....