Aerojet General Liquid-fueled RATO System

The Aerojet General liquid-fueled RATO system in this photo was fired
during a takeoff test at Edwards AFB, CA.

A boost pump provided suction pressure for the rocket fuel pumps. The
oxidizer was supplied to the rocket fuel pumps via a pair of 200-gallon
bleed air pressurized tanks. Ignition was accomplished with a glow plug
located in the rocket's secondary chamber. This fuel/oxidizer mixture
was brought up to 55 pounds pressure to permit ignition. Then ignition
began in the 5,000-pound main thrust chamber that operated at 365
pounds-per-square-inch ambient pressure. During one test at Aerojet's
Azusa Facility in 1952, a thrust chamber in the B-47 mock-up ruptured on
start. Shrapnel punctured one of the oxidizer tanks. These events
coupled with a fuel line rupture resulted in an intense fire that
destroyed the test stand. This incident caused a temporary halt to
testing until the conditions could be eliminated. Before any flight
testing could be accomplished, each design change required a critical
path review and both laboratory and test stand testing.

Four Aerojet YLR45-AJ-1 rocket engines were installed (two per side) in
B-47B-1-BW, s/n 49-2644 for testing at Edwards AFB. This system included
a fuel tank serviced with JP-4 mounted in the fuselage immediately aft
of the rockets and the two oxidizer tanks installed in the rocket
compartments. The rocket engines were deployed to 20 degrees  outboard of the
aircraft centerline for takeoff and retracted to fair into the fuselage
and reduce drag during flight.

Testing of the Aerojet YLR45-AJ-1 system was conducted over 59 test
flights with the maximum gross takeoff weights ranging between 130,000
and 181,000 pounds. Takeoff rolls ranged between 2,425 and 5,445 feet
with the Aerojet system as compared to 9,400 feet without augmentation.
The final test with this system was conducted on 25 August 1954.

No further liquid rocket ATO tests were conducted on the B-47 and the
external rack Aerojet solid propellant systems were employed on
operational Stratojets.

The above is an excerpt from an about-to-be published book authored by Alwyn T Lloyd. We will announce the availability date of the book on this site when known.