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Weight EstimateAs with the Surface Combatant spreadsheets that I am trying to
develop, the weights for Aircraft Carrier type vessels are based on the
US Navy's Ship Work Breakdown Structure (as described on the
Terminology and Background pages of this site. Also as with the
data for Surface Combatants the method used for estimating the weights
for Aircraft Carriers is based the fitting of trendlines to data on
existing ships and designs for each of the main SWBS weight
groups. The majority of the data on the weights of existing
designs used to develop these trendlines come from Dr. Norman
Friedman's book on "US Aircraft Carriers", which has a very informative
appendix containing weight data on a fairly large number of post WWII
US Aircraft Carrying vessels.
Launch and Recovery Issues
With respect to this raw data though, there is an issue that needs to
be addressed regarding the main aircraft carrying support
equipment. In general, aircraft carrying vessels can be
categorized into three or four broad groups depending on how the
aircraft onboard is launched and recovered, as described below.
VTOL - Vessels that operate either helicopters or aircraft capable of pure Vertical launch and recovery are often referred to as Vertical Take-Off and Landing (VTOL) vessels. Vessels such as the fromer USSR's Moskva and the Italian Navy's Vittorio Veneto were examples of this type of vessel. STOVL - Vessels similar to these VTOL ships but which can also accommodate aircraft that make use of a short rolling take-off run (sometimes augmented with a bow mounted "ski-ramp" to increase the payload that the aircraft launch with are typically referred to as Short Take-Off and Vertical Landing (STOVL) vessels. The Royal Navy's Invincible class, the Spanish Principe de Asturias, the Italian Guiseppe Garibaldi, and the Indian Navy's Viraat are examples of this type vessel. The fixed wing aircarft that these type vessels are limited to Short Take-Off and Vertical Landing (or Short Rolling Vertical Landing) type aircraft like the BAe FRS-1 and FA-2 Sea Harrier, the McDonnell Douglas AV8B Harrier II, and the Lockheed Martin F-35B Lighning II. CTOL or CATOBAR - A traditional Aircraft Carrier that uses catapults and arresting gear to launch and recover its aircraft is sometimes often referred to as a Conventional Take-Off and Landing (CTOL) type carrier, or using more recent terminology a Conventional Take-Off and/but Arrested Landing (or CATOBAR) vessel. The USS Nimitz class, the USS Ford class, the Brazilian Sao Paulo and the French Charles de'Gaulle are examples of this type vessel. STOBAR - The final general category of vessels are a bit of a mix between the STOVL and CATOBAR designs, typically incorporating a bow "ski ramp" (in lieu of catapults) to assist in the launching of somewhat conventional fixed wing aircraft (similar to how many STOVL designs also use "ski ramps") but they also incorporate arrestor gear for use in recovering the aircraft. As such these type vessels are typically referred to as Short Take-Off but Arrested Landing (or STOBAR) type vessels. The Russian Kuznetsov, the Chinese Liaoning, and the Indian Navy's new Vikrant class carriers are examples of this type of ship. Because the weight data provided in Dr. Friedman's book is primarily for CATOBAR and STOVL vessels, the weights of the Launch and Recovery equipment is rolled into that data. However, for a new design, it may be desirable to look at alternate launch and recovery configurations. As such, I have made an attempt to identify the weights associated with the Launch and Recovery equipment on the vessels and separate them out from the rest of the ships' weights and develop up trendline data for these revised data. Similarly, I have also made an attempt to do something similar for the primary aircraft lifts/elevators since these too may be items that a designer may wish investigate alternative arrangements for. Links to the Primary Weight Estimating Information
Catapults and Ski Ramps
Arrestor Gear Aircraft Lifts/Elevators SWBS 100 - Structural Weights SWBS 200 - Main Machinery Weights SWBS 300 - Electrical Plant Weights SWBS 400 - Command, Comminucations, Control, Computers & Navigations (C4N or Electronics) Weights SWBS 500 - Auxiliary Systems Weights (including the Aircraft Launch, Recovery, and Lift/Elevator Systems) SWBS 600 - Outfit and Furnishings SWBS 700 - Weaponry SWBS M00 - Margins and Service Life Allowances SWBS F00 - Operational Loads |
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This document maintained by PFJN@mnvdet.com. |