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					The Plane

The Lockheed-Martin F-35 is a single seat, single engine 5th generation tactical fighter

                                                         intended to provide a “first day of war” strike

                                                         platform. It will replace numerous aircraft

                                                         currently in service including the F-16, A-10,

                                                         AV-8B, Sea Harrier and legacy variants of the

                                                         F-18 Hornet.i The F-35 is the product of the

Figure 1 X-35C with F-18D
                                                         Joint Strike Fighter (JSF) program undertaken
http://www.jsf.mil/images/gallery/cdp/lockheed/x35c/th
umbs/cdp_loc_cv_004.jpg                                  in cooperation between USAF, USMC, USN,

RAF, RN, Italy, the Netherlands, Turkey, Canada, Australia, Denmark and Norway.ii

The F-35 program is expected to be the largest defense contract in history, worth more

than $244 billion.iii

           The JSF program came about as a result the cancellation of numerous aircraft

programs, primarily within the Department of the Navy in the years surrounding the end

of the Cold War. With the A-12, A/F-X, and NATF programs eliminated, nearly the all

Navy and Marine Corps tactical jets were approaching the end of their service lives with

no replacements in sight. The cancellation of the Air Force’s Multi-Role Fighter and the

realization that it would be unable to afford the F-22 in the quantity it had intended for

also helped to

           The JSF program can trace its roots to the ASTOVL program which ran from

1983-1994. This was an attempt by DARPA to develop a Short Take Off /Vertical

Landing technology demonstrator that was to be built by Lockheed’s Skunk Works. This

evolved into the SSF program which was to sell a common STOVL-Strike Fighter to the
USAF, USN and USMC. It became clear that a common airframe was a viable option,

however only the USMC and British RN had a need for an STOVL fighter.iv As a result

this program matured into the Common Affordable Lightweight Fighter which was then

along with the A/F-X rolled into the Joint Advanced Strike Technology program, with the

intent of developing the technologies necessary for a next-generation joint strike aircraft.

The JAST program was then again renamed the JSF program, and charged with

developing prototypes for a next-generation strike fighter.v Ultimately prototypes were

built by Lockheed-Martin and Boeing, the X-35 and X-32 respectively and in 2001

Lockheed was given the contract for the JSF.vi

The first production aircraft was completed in

February of 2006 with an expected first flight

in the fall.



The Chute

        The parachute can trace its origins to

atleast 9th century Al-Āndalu (Spain) when a        Figure 2 F-35 Spin Chute
                                                    Spin Chute Recovery System
cloak, with wooden supports, was used to            Instalation, Carl Schwarzbach, 2003

retard a fall from a building. It was not until the late 1800’s, however that “modern”

parachutes were developed as a means to escape from balloons.vii


        The spin chute is a derivative of the classic parachute design used to aid in the

recovery of an aircraft from a spin. Although they are used in the testing of both military

and civilian aircraft, and are even permanently mounted on some civilian aircraft, for the

purposes of this paper we will only study the applications in military aircraft, which tend
to be relatively uniform in design and are exclusively used during the testing of the

aircraft.




                                                                             The need for a spin chute

                                                                             stems from the susceptibility

                                                                             of aircraft to enter into a

                                                                             stable, and potentially

                                                                             unrecoverable condition

                                                                             known as a spin. When

                                                                             engaged in testing, especially

                                                                             at low speeds and high angles

                                                                             of attack (ά) it is possible that
Figure 4 F-22 Spin Chute
http://www.edwards.af.mil/gallery/html_pgs/images/f-22/f22-37_072.jpg
                                                                             a departure from controlled

flight can result in the aircraft entering a spin. As a spin is stable the aircraft will not exit

it without an opposing force. Since the airflow over the control surfaces is greatly

reduced during a spin, it can be difficult or impossible for some aircraft, especially those

designed for high-speed flight, to generate enough force to exit the spin.viii As a result

during testing where a spin could be

encountered it is necessary to add a

spin-chute, a rocket assisted parachute

capable of imparting a substantial m                        Figure 3 Deployed F-22 Spin Chute
                                                            http://www.irvinaerospace.com/build.html
oment on the aircraft and aiding it in

recovering from a spin.
          As a spin chute adds unnecessary weight and drag which can alter an aircraft’s

performance as well as its radar cross section they are not generally installed except

during phases of testing likely to induce a spin. This testing allows for a sufficient

understanding of the aircraft’s departure characteristics so that once it has entered service

pilots can be trained in how to avoid, and recover from spins. Additionally the computer

system on modern “fly-by-wire” aircraft can help the pilot maintain avoid entering a spin,

and a “spin recovery mode” can allow the aircraft to more easily return to controlled

flight.

i
  Program, JSF.mil, http://www.jsf.mil/program/
ii
    International Partnerships, Lockheed Martin,
http://www.lockheedmartin.com/wms/findPage.do?dsp=fec&ci=15153&rsbci=11173&fti=0&ti=0&sc=400
iii
     F-35, Wikipedia, http://en.wikipedia.org/wiki/F-35_Joint_Strike_Fighter
iv
    Pre JAST History, JSF.mil, http://www.jsf.mil/history/his_prejast.htm
v
   JSF History, JSF.mil, http://www.jsf.mil/history/his_jsf.htm
vi
    F-35 Joint Strike Fighter, Global Security, http://www.globalsecurity.org/military/systems/aircraft/f-
35.htm
vii
     Parachute, Wikipedia, http://en.wikipedia.org/wiki/Parachute
viii
     Spin, Wikipedia, http://en.wikipedia.org/wiki/Spin_%28flight%29

				
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