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C-5 Air Data Computer

Technical Information

Catalogue No: C0158
Category: Air Data
Object Type: Signal/Data Processor
Object Name: C-5 Air Data Computer
Part No: 50-001-08
Serial No: 0001
Manufacturer: Elliott Bros
Division: Unknown
Platform(s): C-5A/B Galaxy 
Year of Manufacture: 1966
Dimensions:
Width (mm):
200 
Height (mm):
200 
Depth (mm):
560 
Weight (g):
16,000 
Location: Main Object Store
Inscription(s):

Computer Central Air Data, MC 0159A

Notes:

This is an Air Data Computer from 1967 designed for the C-5A The Lockheed C-5 Galaxy is a large military transport aircraft built by Lockheed. It provides the United States Air Force (USAF) with a heavy intercontinental-range strategic airlift capability and has been operated by the USAF since 1969.
An Air Data Computer computes altitude, vertical speed, air speed, and mach number from sensor inputs such as pitot and static pressure and temperature. The early systems were electromechanical computers, and Elliotts backround wasas much in electronics as in precision gear making. After WWII Elliotts was acquired by Leon Bagrit who already managed Swift and Swallow on the Rochester site. During the Second World War the manufacturing company, styled B & P Swift Limited turned to war work, and manufactured aircraft equipment for the Ministry of Aircraft Production. This included flap and undercarriage actuators, which called for good gear and screw-cutting facilities and they also had a commercial arm making weighing scales which required gear wheels. Elliotts gained a precision gear capability and this can be seen in the early instruments such as this Air Data Computer,



An order for modular air data computers for British-built Jaguars, worth more than £250,000, was placed with Elliott Flight Automation by Mintech in1970. The unit was the smallest and lightest for its performance yet developed. A pre-production unit was flown in the S.06 prototype on its first flight in1969. The air data computer in the Jaguar forms a single central source of corrected signals of height, indicated airspeed, true airspeed, Mach number and related information, giving 16 different outputs for flight instruments, head-up display, navigation and weapon aiming. It also provides a digitised output of height for automatic altitude reporting through the secondary radar transponder. Individual functional modules can be replaced without recalibrating The mechanical transmission between modules also reduces weight and improves reliability.

The Air Data Computer was made lighter and smaller similar to the range of air data computers which were already being produced for the Nimrod, the American Lockheed C-5A heavy logistics transport, BAC One-Eleven, HS.748s for the Royal Australian Air Force and for the engine intake control system of the Concorde.

In 1981 Instrument Systems Division began the design of a new generation of Air Data Computers designed for the combined USAF and USN Standard Central Air Data Computer (SCADC) programme. The system was designed to fulfil the retrofit requirements of 38 different aircraft types and to do so with only four configurations. The aircraft types include the following:-

A-4M and TA-4J Skyhawk, A-6E/F, KA-6D and EA-6A Intruder, EA-6B Prowler, TC-4C Gulfstream, A-7D/E/K and TA-7C Corsair II, C-2A Greyhound, E-2C Hawkeye, KC-135 Stratotanker, C-5A/B Galaxy, C-141A/B Starlifter, F-111A/E/D/F, FB-111A, EF-111A, F-4C/D/E/G/J/N/S, and RF-4B/C Phantom and the S-3A/B and US-3A Viking. In 1992 an order for a further 290 units was received, being the eighth option, bringing the total procured to 5552 units. 387 units of the SCADC system were at this time being supplied for the F-14 Tomcat.

The high commonality was achieved with a unique software re-configurable design. Output parameters, ranges and scalings are selected for each aircraft type by the software, which recognises the host from a code wired into the aircraft connector pins. The SCADC core hardware set provides over 80% of the hardware in every application and the remainder is addressed by one or two special-to-type modules. A multiplicity of analogue interfaces can be handled and the Mil-Std 1553 DataBus is also a feature. Production commenced in 1985 with first deliveries the following year and in 1989 these deliveries surpassed 4,000 units. In addition in 1988 ISD received the Queen’s Award for Technological Achievement for SCADC.

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