Design Report Guided Missile Submarine SSG(X) - AOE - Virginia ...

SSG(X) Design – VT Team 3 Page 76
Table 49 shows a summary of the speed and endurance calculations. The range for each condition meets the
ORD requirement.
Condition Thrust
(kN)
Table 49 - Summary of Speed and Endurance Calculations
Overall
SHP
(kW)
ηProp
Efficiency
THP/DHP
ηPC
(Propulsion
Coefficient)
Range ORD
Requirement
AIP Endurance 18.14 58.6 0.716 0.882 25.7 days 26 days
AIP Sprint 298.6 4129 0.735 0.906 1 hr/
22 nm
20 nm
Snorkel 94.71 1061 0.716 0.882 5610 nm 5280 nm
4.5.4 Propulsor Selection
The propulsor type in variant 44 is a Rim Driven Podded Propulsor (RDP). If feasible, a single RDP is more
efficient and producible. A single RDP would also have a reduced signature. However, a double RDP configuration
would have greater survivability from redundancy and may have advantages in maneuvering.
The maximum brakehorse power required with electric loads included for the SSG(X) is 6.5 MW at sprint. The
information from Table 50 shows the feasibility of a single propulsor. [Blarcom, Hanhinen, and Mewis, SNAME,
2003]
Table 50 - RDP Capabilities
ABB Azipod EB’s CRDP SSG(X) Requirement
Nominal Power Rating ~20 MW 18.5 MW 6.5 MW
Continuous Torque Rating ~1340 kN-m (est) 1918 kN-m 1000 (est)
Length 11.40 m 3.90 m 3 m (est)
Hub Diameter 2.85 m 1.46 m 1.2 m (est)
Propeller Diameter 5.80 m 4.90 m (propeller)
5.85 m (duct)
4.5 m
Figure 71 shows the envelope hull with the single RDP. The propeller diameter is 14.75 ft and the shroud
length is 12 feet.
4.5.5 Electric Load Analysis (ELA)
Figure 71 - SSG(X) Hull with RDP
Table 52 shows a summary of the Electric Load Analysis (ELA). The electric load conditions analyzed are
AIP, snorkel, and sprint. The ELA was created by making worksheets for each SWBS group and using data from
the Machinery Equipment List shown in Table 51 (Full MEL shown in Appendix E) and combat systems to
determine what equipment needed power and how much was required. Load factors were then applied for each
condition. The summary table below comes from this information. Analysis of the power available from the