Weight Estimate
As 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