A Century of Ramjet Propulsion Technology Evolution - Faculty of ...

Table 5 Worldwide scramjet evolution 1955–1990
Cruise Powered Total Total
Engine Cruise altitude, range, length, Diameter, weight, State of
Era Country/service Engine/vehicle type Dates, year Mach no. ft n mile Launcher in. in. lbm development
1955–1975 U.S. Navy External burnb ERJ 1957–1962 5–7 —— —— —— —— —— —— Combustion tests
Russia Chetinkov research ERJ 1957–1960 5–7 —— —— —— —— —— —— Component tests
U.S. Air Force Marquardt SJ DMSJ 1960–1970 3–5 —— —— —— 88 10 × 15 —— Cooled engine tests
U.S. Air Force GASL SJa SJ 1961–1968 3–12 —— —— —— 40 31 in2 —— Cooled engine tests
U.S. Navy SCRAMb LFSJ 1962–1977 7.5 100,000 350 Rail 288 26.2 5,470 Free-jet test
U.S. Air Force IFTVc H2/SJ 1965–1967 5–6 56,000 —— —— —— —— —— Component tests
U.S. Air Force–NASA HREa H2/SJ 1966–1974 4–7 —— —— —— 87 18 —— Flowpath tests
NASA AIMb H2/SJ 1970–1984 4–7 —— —— —— 87 18 —— Cooled engine tests
France ESOPEb DMSJ 1973–1974 5–7 —— —— —— 87 18 —— Component tests
1975–1990 U.S. Navy WADM/HyWADMb DCR 1977–1986 4–6 80,000–100,000 500–900 VLS 256 21 3,750 Component tests
Russia Various research SJ/DCR 1980–1991 5–7 80,000–100,000 —— —— —— —— —— Combustion tests
NASA NASPb MCSJ 1986–1994 0–26 0–orbit Orbital Runway —— —— 500,000 Free-jet test (M7)
Germany Sänger IIb ATRJ 1988–1994 4 0–orbit Orbital Runway 3976 550 800,000 Concept vehicle
c IFTV incremental flight test vehicle.
discussed.
a System discussed and shown. b System
FRY 39
Fig. 9 France’s first ramjet-propelled flight tested airplane (1933–
1951).
Fig. 10 German Sänger I Hypersonic Concept Vehicle (1936–1945). 34
as an air-launched vehicle from another aircraft. Refined versions
of this aircraft followed over the years with the subsequent development
of the Griffin II. Throughout this chronology, the dates in the
figure captions are intended to reflect a total time interval including
development, testing, and operation if applicable.
In the late 1930s, Eugen Sänger, one of Germany’s top theoreticians
on hypersonic dynamics and ramjets, and his wife, mathematician
Irene Bredt, had begun developing a suborbital rocket
bomber, Sänger I (Fig. 10) or RaBo, (sometimes called the Antipodal
Bomber) that would be capable of attacking targets at intercontinental
ranges. 34 Highly advanced concepts, including swept,
wedge-shaped supersonic airfoils, a flat, heat-dissipating fuselage
undersurface that anticipated the space shuttle’s design by 30 years,
and rocket engines of extraordinary thrust were incorporated in the
RaBo concept that would have taken many years to develop. In 1944,
Sänger and Bredt were moved to an isolated laboratory complex in
the mountains near Lofer, Austria, where a number of advanced
research projects were underway. Most sources indicate that nothing
much came of the Amerika Bomber project at Lofer, but this
is clearly not the case. The Russians recovered copies of Sänger’s
RaBo reports and were so fascinated with the concept that they
dedicated effort to designing an updated RaBo (Antipodal Bomber)
equipped with huge ramjet engines for boost and cruise propulsion.
The RaBo influenced Soviet manned and unmanned rocket work
for years after the war. It influenced U.S. work, too, leading directly
to the Walter Dornberger-sponsored Bell bomber missile (BoMi)
project of the early 1950s, and ultimately the U.S. Air Force/Boeing
X-20 Dyna Soar hypersonic glider program that laid the technical
groundwork for the space shuttle. The Sänger work to achieve Earth
orbit recognized the need for airbreathing propulsion and suggested
a preference for a SSTO vehicle.
Both the Sänger–Bredt RaBo of 1945 and the postwar Soviet
derivative used a long rocket sled to propel the vehicle to its takeoff
speed of several hundred miles per hour. After launch, an onboard
engine of some 200,000-lb thrust would propel the craft into a ballistic
trajectory that peaked at altitudes of several hundred miles. The
German version was intended to be able to reach friendly territory
after making its strike, or possibly ditch near a U-boat. The Soviet
version had ramjets to provide ascent boost and possibly returnto-base
cruise capability after velocity decayed into the supersonic
range. After the RaBo arced to altitudes of several hundred miles