The seeker, which sees the infrared light from the target

The guidance control electronics, which process the information from the seeker and calculate the proper course for the missile













The control actuation section, which adjusts flight fins near the nose of the missile based on instructions from the guidance electronics

The target detector, a series of lasers and sensors which detect the presence of a target.

The warhead, the explosive device that actually destroys the enemy aircraft

The rocket motor, which provides the thrust to propel the missile through the air

A fuze system that sets the warhead off when the missile reaches the target

A battery to provide power to the onboard electronics

The rear stabilizing wings, which provide the necessary lift to keep the missile aloft












High Desert Memories - A Hometown Journal Commemorating Ridgecrest California
China Lake
Page 7
 
Select a page number above
to move from page to page
Select a page number above
to move from page to page
 
 
AIM-9 Sidewinder Missile


                           Primary function: Close-range, air-to-air missile.
                        
                           Length: 9 feet, 6 inches (2.89 meters)

                           Weight: 186 pounds (84.44 kilograms)

                           Span: 2 feet (60.96 centimeters)

                           Diameter: 5 inches (12.7 centimeters)

                           Propulsion: Solid-fuel rocket

                           Guidance: Infrared homing

                           Warhead: Conventional

                           Speed: Mach 2.5

                           Platforms: F/A-18, AV-8, AH-1

                         
Unit Replacement Cost: $83,000


The flight fins themselves, which steer the missiles through the air -- just like the flaps on an airplane wing, the moving flight fins generate drag (increase wind resistance) on one side of the missile, causing it to turn in that direction.
Each of the four rear wings, which provide the necessary lift to keep the missile flying, is outfitted with a simple stabilizing device called a rolleron. Basically, a rolleron is a metal wheel with notches cut into it. As the missile speeds through the air, the air current spins the rolleron like a pinwheel.     The gyroscopic motion of the rollerons counteracts the missile's tendency to roll -- to rotate about its central axis. The simple, cheap rollerons steady the missile as it zips through the air, which keeps the seeker assembly from spinning at top speed. This makes it a lot easier to track the target.
Features: The AIM-9 Sidewinder is a short-range, air-to-air missile that uses an infrared seeker, enhanced warhead, and guidance permitting all-angle attacks. It is the most widely used air-to-air missile in the West, with more than 110,000 missiles produced for 27 nations excluding the U.S. The AIM-9X follow-on variant is planned as a high-off-boresight replacement/upgrade to current missile.
   In the early days of aerial combat, the pilots who prevailed were the ones who best learned how to maneuver their aircraft, manage their energy, and employ their armament, the gun. These successful “dogfighting” skills became a part of their everyday training to help ensure future survivability of the aircrew.  During WWII, many U.S. aviators faced adversaries with equal or comparable skills and a need was born to provide U.S. flyers with a combat edge.  In the late 40's there were missiles with radar detecting systems aboard but they were dismal failures at downing aircraft.  Some attempts at Infrared guidance had been tested without much success.

In 1949, a small team at NOTS (later NWC) China Lake, led by Dr. McLean, investigated the passive Infra Red homing problem, with limited financial means.  The name of this project was taken from the name of a snake which is a denizen of the Mojave Desert called the Sidewinder.

McLean sketched what would become the future of dogfighting weapons, the AIM-9 Sidewinder missile.  Surprisingly, the result of this low-profile research project is still known as one of the world's leading dogfight missiles. As if the financial limitations were not restrictive enough, the team imposed on itself one further restriction: it chose for an airframe of only 5 inch (127mm) diameter, which made fitting in the necessary electronics (still vacuum-tube in those days) a major challenge. The research led to a contract, awarded to Philco in 1951, for a homing head.

The primary advantage to the Sidewinder was its use of a very sophisticated detection/guidance system. In WWII the Germans had experiments with infrared guidance systems in a large missile known as the Enzian but were unable to get it to work reliably. The system used an IR detector mounted in a small steerable telescope, and used a vane in front of the mirror to tell on which side of center the target was in order to guide. By continually trying to turn the missile body toward the current direction of the telescope, the missile would guide toward the target using what is known as a pure pursuit.

The Sidewinder improved on this in a number of ways. The first was to replace the "steering" mirror with a system using a mirror that was rotating around a shaft pointed out the front of the missile, with the detector mounted in a fixed location in front of it (not to the mirror). Instead of attempting to track the target in the mirror, the IR sensor would see the target as brief flashes as the mirror lined up with the target. By knowing where the flash was as the mirror spun, the direction (radially) to the target was also known. In addition this system could track the angle-off to the target in a clever manner. If the target was further to the side of the field of view, the flash seen in the detector would be shorter due to the mirror's higher rate of motion at the outside.

Finally this sort of signal made the tracking system both simpler and much better. Instead of simply pointing the missile at the target (which is inefficient) the guidance system, the Sidewinder "remembered" each flash's direction and time. By attempting to zero out the changes, instead of the difference between the detector and missile angles, the Sidewinder flew a course known as proportional pursuit, which is much more efficient and makes the missile "lead" the target.

However this system also requires the missile to have a fixed angle of flight. If the missile spins at all, the timing based on the speed of rotation of the mirror is no longer accurate. Correcting for this spin would normally require some sort of sensor to tell which way is "down" and then adding control inputs to correct it. Instead the Sidewinder engineers came up with a very clever solution. Small control surfaces were placed at the rear of the missile with spinning disks on their outer surface. Airflow over the disk would spin them to a high speed, and if the missile started to roll, the gyroscopic force of the disk would drive the control surface into the airflow and produce the opposite control input. Thus the Sidewinder team replaced a potentially complex control system with a small bit of metal.

A prototype Sidewinder, the XAAM-N-7 (later AIM-9A), was first fired successfully in September 1953. The initial production version, designated AAM-N-7 (later AIM-9B), entered operational use in 1956, and has been improved upon steadily since. The first combat use of the Sidewinder was in 1958 with the air force of the Republic of China on Taiwan. During that period of time, the ROC was engaged in air battles with the People's Republic of China over the Taiwan Strait. The United States provided a few dozen Sidewinders to ROC forces, which used them to great effect against PRC MiG-15s, adding a new element to an air war which had formerly been fought only with guns.

Sidewinder is undoubtedly the most influential heat-seeking missile in the history of air warfare. More than 200,000 of the missiles have been built for 40 countries around the world and it has achieved more than 175 kills in air combat. The Sidewinder originally developed and improved at China Lake became the yardstick against which all heat-seeking missiles have been measured.


Although originally developed for the USN, the Sidewinder was subsequently adopted by the USAF as the GAR-8 (later AIM-9E). During the 1960s the USN and USAF pursued their own separate versions of the Sidewinder, but cost considerations later forced the development of common variants.

The Sidewinder subsequently evolved through a series of upgraded versions with newer, more sensitive seekers with various types of cooling and various propulsion, fuse, and warhead improvements.

  
Early Sidewinders consisted of sections of cylindrical aluminum tube, with the seeker head fitted at the front end together with the control fins. The rear end has four fixed fins, each containing a so-called 'rolleron'. These patented rollerons are in fact small wheels, one of which is mounted at the rear tip of each fixed tailfin. These wheels are slightly milled at the edges, so they are made to spin at high-speed by the slipstream. The rollerons act as air-driven mini-gyros, their inertial moment resisting every change in attitude. This way, they tend to roll-stabilize the missile. Both tailfins and control surfaces are in a cross-like arrangement.

The missile's main components are an infrared homing guidance section, an active optical target detector, a high-explosive warhead, and a rocket motor. The infrared guidance head enables the missile to home on target aircraft engine exhaust. An infrared unit costs less than other types of guidance systems, and can be used in day/night and electronic countermeasures conditions. The infrared seeker also permits the pilot to launch the missile, then leave the area or take evasive action while the missile guides itself to the target. The early models used an uncooled PbS (Leadsulfide) seeker which yielded a 70% SSKP (Single-Shot Kill Probability) in ideal conditions, but extremely bad results in less-than-ideal circumstances. The seeker showed a tendency to lock-on to the sun or reflections from water surfaces. De original solid-engine was produced by Hunter-Douglas, Hercules and Norris-Thermador, and accelerated the missile to Mach 2.5 in 2.2 seconds.
The picture above illustrates the physically apparent   changes to the missiles exterior as a result of the progressive changes made to it over the past 50 years.
  The diagram above illustrates the family tree of development during the last 50 years.
  Originally designed to be launched from fighter aircraft the AIM-9 has been adapted for use by all types of aircraft.  Above you see a launch from an Army helicopter.
  One of the primary defenses against an infrared heat seeking missile is the firing of flares as a countermeasure.  Most fighter attack aircraft are equipped with a flare dispensing system. 
  The photos above depict the firing cycle of the missile. 
. 1 & 2  -  In the beginning
   3        -  Naval Air Facility
   4        -  The Ranges
   5   -        Doc the B-29
   6   -        NAWC Museum
. 1 & 2  -  In the beginning
   3        -  Naval Air Facility
   4        -  The Ranges
   5   -        Doc the B-29
   6   -      NAWC Museum
    7   -        The Sidewinder
    8    -     
Weather
  
9    -      60 Year FED service
   10  -      
China Lake named
                  National Historic site
|_1_|_2_|_3_|_4_|_5_|_6_|_7_|_8_|_9_|_10_|
|_1_|_2_|_3_|_4_|_5_|_6_|_7_|_8_|_9_|_10_|
    7   -        The Sidewinder
    8    -      
Weather
  
9    -      60 Year FED service
   10  -      
China Lake named
                  National Historic site
   All the  folks who worked out on the ranges, in the Lab, etc., provided a real backbone to our Navy!!  Couple points for your site history--my Dad was a Ph.D in Physics out of Johns Hopkins, and headed up Physics division of Mike Lab for years.  Recruited Ernst Bauer and a bunch of other good German boys from Germany, for the Lab, and these guys were great physicists.  Dad's research was in optics, multiple beam interferometry (still can't spell it), and led to lasers of today.  Those German scientists he brought in and trained became real contributors.  My point is, Dad knew Bill McLain (we all knew Lavee) real well, and the point of interest is that in mid development on the Sidewinder, Navy and Govt. elected to "pull the plug" on money and the continuation of the project.  Bill pulled $50,000 out of his savngs account to keep the project going, as I understand it, and the result is the Sidewinder came to fruition, many mods later is in the arsenal of many Free World countries, and was so cost-effective to produce even back in the late Fifties!!!  Bill McClain was an unbelievable guy----real hero!!

   Also, another item, there was a film on China Lake and its development and mission, put out for a big reunion about 10 years or so ago.  I had a copy, but sent to Captain Vejtasa, who used to run VX-5 I think it was, while stationed at the base.  He is 91, retired in Escondido, and has been featured in "Dogfights" on the military history channel on Friday nites. One example of this guy's capabilities:  in a single day of air combat in the Pacific, flying off the Coral Sea I believe, he shot down 7 Japanese Zeros.  In one day!! Was awarded not one, but two or three Silver Stars!! Google Captain Stanley W. "Swede" Vejtasa military record,  and read about this guy.  His son Gene coached and taught at BHS, retired in Ridgecrest, and we grew up together and have been friends for all these years.  Gene was a Marine Recon Capt. in Nam, and if you know what Recon is, you know what he did, behind enemy lines, for several weeks at a time, no fires, dry food, blowing up eneny supply lines, etc., and frequent firefights.   Anyhow, just some "off the cuff" stories about folks that were at China Lake.  Oh, Wally Shirra (sp?) the original Mercury 7 astronaut was stationed there, and taught my wife's mother French in China Lake's adult ed classes.  Captain Tom Moorer, was stationed at the Base, later Chairman of Jt Chiefs, and good old Zumwalt too!!  Amazing folks!!

  Gary  Koehler
 
 
Some personal comments about the development of the Sidewinder and the people
       who designed and supported it and other projects on the Naval Station.