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Enhanced Reliability Features of the RL10E 1.pdf

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48th IAF Congress

The program was managed using the Integrated
Product Team (IPT) approach. Component Integrated
Product Teams (CIPT’s) were assigned one or more
areas for upgrade. The CIPT’s reported to a higher level
System Engineering Integration Team and a Program
Management Team. Team members included the
engine manufacturer (P&W), the vehicle manufacturer
(LMA), the USAF, The Aerospace Corporation, and
the National Aeronautics and Space Administration
The AREP program was terminated in April 1997
for the convenience of the USAF. An RLIOE-1
prototype test engine and two development engines
were tested prior to termination, while component
development testing was nearing completion. Many cf
Other potential enhanced reliability
features are available but have not yet been
demonstrated. Major reliability enhancing features of the
fU I OE- 1 will be discussed.
The RLIO engine family consists of multi-start
engines capable of mixture ratio (MR) control to
maximize vehicle propellant usage. These engines use
an expander cycle, in which heat absorbed tiom the
thrust chamber cooling jacket vaporizes hydrogen and
powers the turbine that drives the propellant pumps.

Figure 2: RLlOA41

The RLlOA-3-3A engine is currently flown on
Titan Centaur (TIC). It has a nominal vacuum thrust
and specific impulse (1s~) at MR=5.0 of 16,500 Ibf and
444 set, respectively. The higher thrust RLlOA-4 and
even higher thrust RLlOA4I
engines are currently
flown on Atlas Centaur (A/C). Both these engines use a
new LOX pump and turbine. The RL IOA4 I also uses
a modified main injector. An extendible, columbium
nozzle extension with increased expansion ratio can be
used to improve thrust (+300 Ibf) and Isp. With the
nozzle extension at MR=5.5, the RL10A-4 can achieve
a vacuum performance (thrust and Isp) of 20,800 Ibf and
449 set, while the RLlOA41 can achieve 22,300 lbf
and 451 sec. The RLlOA41 is the current production
engine. Each Centaur uses two RLlO engines.
In-flight cooldown, start, and shutdown for all
these engines are activated by three solenoid valves
which provide pneumatic actuation pressure to the five
primary propellant control valves (see Figure 2, for the
RL 1OA4 1). In all, twelve valves and solenoids enable
ground pre-chill, in-flight prestart cooldown, ignition,
acceleration to steady state, chamber pressure control,
mixture ratio control, and engine shutdown. The
weight of the RLlOA4I
engine, not including the
vehicle supplied propellant utilization motor and the
nozzle extension, is 320 Ibs. The nozzle extension,
when used, adds 55 Ibs to engine weight.


Flow Schematic.