The turbopump, rotating at 4000 rpm, forced the alcohol and oxygen into the combustion chamber at 33 gallons per second, where they were ignited by a spinning electrical igniter. Thrust increased to 8 tons during this preliminary stage, before increasing to 25 tons, lifting the 13.5 ton rocket. Combustion gases exited the chamber at , and a speed of 6500 feet per second. The oxygen to fuel mixture was 1.0:0.85 at 25 tons of thrust, but as ambient pressure decreased with flight altitude, thrust increased until it reached 29 tons. The turbopump assembly contained two centrifugal pumps, one for the alcohol, and one for the oxygen, both connected to a common shaft. Hydrogen peroxide converted to steam, using a sodium permanganate catalyst powered the pump, which delivered 120 pounds of alcohol and 150 pounds of liquid oxygen per second to a combustion chamber at 210 psi.