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YC-14 Interface Unit (space model)

Technical Information

Catalogue No: C0319
Category: Flight Control
Object Type: Model
Object Name: YC-14 Interface Unit (space model)
Part No: 31-008-04
Serial No: None
Manufacturer: Marconi-Elliott Avionic Systems Ltd
Division: Unknown
Platform(s): YC-14
Year of Manufacture: 1975
Dimensions: Width (mm): 193
Height (mm): 197
Depth (mm): 385
Weight (g): 2,420
Location: Rack RAA01 [Main Store]

Marconi-Elliott Avionics
Interface Unit
Part No. 31-008-04
Serial No.
Boeing Part No. 748-253120-2
[paper label]
Boeing YC14 Interface Unit 1975


The YC-14 was an experimental STOL aircraft made by Boeing. It had a high wing with the twin engines mounted above the wing and Blown Flaps to give the STOL performance. The Digital Flight Control System provides full control of all primary aerodynamic control surfaces and engine thrust. The objective was to reduce crew workload during the busy STOL mode to a level compatible with a two-man crew. The system has full fly-by-wire control and has a variety of operating modes such as STOL, high Mach or high altitude cruise, low altitude, stores delivery and single engine operation. The system is triple redundant to meet mission and safety reliability requirements. Data is transmitted between channels via a single time multiplexed fibre-optic link which provides complete electrical isolation between redundant channels and eliminates electromagnetic interference.

A full aircraft set of equipment comprises three Computer Units (CU), three Interface Units (IU), three Optical Coupler Units (OCU), three Optical Data Links (ODL), a Control and Display Panel (CDP) and a Test/Fail Ident Panel (T/FIP).

The Computer Unit and the Interface Unit are ¾ATR short LRU. Design, tooling and manufacturing costs have been minimised through the use of common chassis, card and PSU constructions for these two unit types. All of the processing, memory and digital interfacing circuits are housed in the Computer Unit. The 16 bit processor includes features specific to fail operational applications and operates in conjunction with semi-conductor memories providing a total memory capacity in excess of 16,000 words. A parallel digital highway provides communication between the Computer Unit and the Interface Unit. Analogue and discrete conditioning circuits contained in the latter unit reflect the particular interfacing characteristics of the YC-14 EFCS and include autothrottle and electrical command servo amplifiers and flight test interfacing circuitry.

The RAA contains a number of models of equipment and aircraft. The equipment models were used as a marketing aid and often to ensure that the production unit will fit in the space; this was particularly true for Head Up Displays. Such equipment models will have minimal or no functionality. Models might  just be used as weighted units or as cockpit lighting evaluation units. The HUD used on the YF-16 was of the correct weight and envelope but only mounted the Spin 'chute button (a feature only required for the early test flights). Many of these models were made by professional model makers from the original drawings and could be quite expensive; alternatively the real hardware would be used.

The aircraft models range from the simple small scale kits to quite large display items. The large model aircraft were often a marketing tool from places like Airbus or Boeing but may be found in Boardrooms or Reception areas wheras the small models may be given as a visitor handout. Those models made from kits have largely been brought in from home but are useful to illustrate the platform alongside the equipment. The large models will be hugely expensive.

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