Aircraft avionics teardown - Tornado jet fighter LRU interface unit - what's inside?
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- เผยแพร่เมื่อ 19 ก.ย. 2020
- Here I tear down a Line Replaceable Unit from a RAF Tornado jet fighter aircraft. A LRU is aviation speak for the black box(es) that sit in the avionics / equipment bay of an aircraft which contain the electronics for the various on board systems and computers. This box has been confirmed to be the "HUDWAC" - responsible for generating the symbology and graphics for the head up display from the serial data sent over the aircraft's data bus from the various other systems. The data interface is similar to RS485 using the Panavia data protocol which is a proprietary standard used for their aircraft.
The Tornado aircraft was retired from service in the UK's RAF last year (2019) being replaced by F35's and Eurofighters. The box dates from 1978 / 1979 as it is part of the original avionics suite when the aircraft was put into service. They had an avionics upgrade circa 2000 I believe where the cockpit instruments were replaced with LCD displays rather than analog dials and the navigation system (TARDIS) updated to full colour high resolution LCD's. Now presumably the LRU's were replaced too; I highly doubt there were 1970's electronics still in use onboard an aircraft in 2019!
** UPDATE** Yes, they were using some of the original avionics up until the aircraft was retired. I found another interface unit on eBay that had the service documentation with it stating the fault and the aircraft it was removed from. It was removed and replacement LRU fitted to the aircraft in September 2018.
It is very well engineered and consists of 14 circuit boards that plug into a backplane consisting mainly of analog circuity such as comparators and op-amps with several other boards containing 54 series TTL (military spec of 74 series TTL) which from what I gather form a interface between various sensors and the main computer of the aircraft. I later found out that the unidentified DDC branded gold modules are likely to be MIL-STD-1553 transceiver modules. EDIT: They are indeed transceivers but the aircraft does not use the MIL-STD-1553 databus; rather a proprietary system using a serial interface based on RS485.
This is an" interface 1" LRU; the Tornado had two interface units presumably connecting several systems and sensors to the main computer. The circuit cards contained inside of the interface 1 LRU depends on what model aircraft it came from; there were several variants of the Tornado such as the GR1, GR4 and ADV. I believe this came from the ADV variant as I found the same unit on ebay with a slightly different part number which mentioned the particular aircraft it came from. That was a GR4.
Speaking of the main computer I managed to find out that it does not have a CPU, rather it is discrete consisting of several boards packed with TTL logic gates. The avionics were designed in the early to mid 70's when microprocessors were in their infancy. Unfortunately there isn't much information on any of the Tornado's avionics, sources I found were a forum with former service technicians contributing and the Rochester Avionics Archive over at BAE Systems. There are several sellers on eBay selling various Tornado parts. Beware though when buying electronic modules; a lot have had their guts removed so they are literally empty black boxes. The sellers fail to mention this.
Anyway, if you do have any information and / or any comments please comment below. Also visit my blog at www.adrian-smith31.co.uk/blog for a detailed article and high resolution photos of the circuit boards.
Finally, you may be wondering what on earth I'm going to do with this thing. Well it's made of high quality aluminium and if all the electronics are stripped out it would make a great project box. I have a high current power supply project in mind and this would make an unique case to put it in.
The PCB's I will either dispose of or sell on eBay. If anyone is interested in purchasing them or the box as a whole, let me know. That will have to be quick though as I will be getting rid of it eventually. It weighs a ton and takes up space. It was bought really as a curiosity item and it was fairly cheap.
If this video is a success, I may do other obscure electronics teardown videos. I just need a source of cheap and / or useless obscure crap for me to tear apart.
#avionics
#teardowns - วิทยาศาสตร์และเทคโนโลยี
Hi Mr. Adrian, I saw your channel, it was very exciting for me and I subscribed to it and I liked it. I love tear down of old electronic circuits and I am looking forward to your next videos.
I have some more things to tear down and try and repurpose. Waiting for a good day to do them so may be after Xmas now. Have got some projects that I might finish first and put them on TH-cam.
He’s finally back
Yeah I've had to return to work so playtime over bah. 😟
Adrian S yea same here work has messed up my upload schedule
I also collect stuff. Thanks for demonstrating such a thing.
Glad you enjoyed it!
Stuff and things, my two favorite entities!
Ahh good video - that is the HUDWAC. This box created the symbology on the Gr.1's head up display. Quite amazing technology these days as it accepted fully digital inputs via Panavia link protocol and the box extracted the relevant data.
That's great information, thanks. I noticed one of these units in the aircraft behind the nose cone so I guessed it was either for instrumentation or flight inputs. I assumed it used MIL-1553 data but I guess when this was built it was before such standards existed. Good to know what this box does or more accurately did.
@@adriansmith31 No - it does not use MIL1553 - the Panavia link inputs are a strange mixture from RS485 levels and a unique serial protocol running over it (32bit words with tag and 16bit payload each). The metal can components are probably the high-speed DACs driving the X and Y inputs of the HUD. A friend is working on restoring a Gr.1 HUD together with one of these boxes I donated to him - we see already some symbology ;-)
@@finner4463 cool, would be interesting to see his progress on it. My box had the MOD paperwork saying it was serviceable but it was damaged so I don't know if it worked or not. The paperwork didn't specify the aircraft tail number. I think the DDC branded modules are likely the transceivers and DACs for the data inputs as DDC make the later MIL-1553 modules too.
Very good video. I like that part of video with checking all of boards in that interface unit. As interface doesn't contain CPU, that explains why there many of boards that contains logic gates
Yeah it's typical of the age, they could have used an ancient cpu such as an 8080 but I don't think this box is doing much processing. That will be done by the main computer although I've heard on a forum that's all discrete logic gates too.
Yeah, for instance, the Panavia Tornado dual-mode (GMR and TFR) RADAR's LRU 1 (Processor / Computer) was an ALL TTL design, except for the TFR (Terrain Following RADAR) 'CRAM' (Clearance Range Ahead Monitor) board that was based on the TI TMS9900 microprocessor.
Good to know, thanks
21:39 It's a "CAW-5 HI-G Mil Spec vers of a712-5 Teledyne Relay" I found a pic of it via google. I figured it was a relay since all of the properties are printed on the case. Eight pins, two for the coil (1560 ohm, 1A, 26.5 VDC) two for common, two for normally closed, and two for normally open. Interesting that they used an electromechanical relay in an avionics package for a fighter jet.
Cool thanks for that information. It's hard to find anything on these old components that are only used in military hardware.
TO-5 (a common package style) 'can' relays - typical for the era (I worked at defense contractor in that era).
All these high quality DIL chips might be great to use for people that like to learn or tinker with electronics on breadboards ... the problem would be getting them out, normally you can desolder them quite clean with a heat gun but.... conformal coatings can make that into a very messy affair ....
Yes they would be difficult to remove without damaging them. The conformal coating was quite thick on these boards.
Yes ! It is the same as on electronic Units in my MB W126 Car. If Parts get hot, the coating isolates the soldering. You have to degrease the Parts first properly, than you can solder the pieces. @@adriansmith31
the double cards are synchro output cards driving the HSI and other systems
Good to know, thanks. Do you know what the other cards do?
I wonder ... is this the "MC", the Main Computer the (what we termed "MRCA") RADAR LRU 1 (Processor/Computer) talked to? There was a dedicated synchronous serial line (data and clock) for communications between these two aircraft systems.
This isn't the main computer, it's just an interface unit which I'm led to believe connects to the HUD and some of the flight control inputs. It's mid to late 70's tech and I would like to see what is in the main computer LRU (there was one on eBay the last time I looked) but it was way too expensive. I suspect the main computer would have a very basic CPU if at all. Might be a discrete component CPU or custom IC's.
But yeah, this almost certainly did talk to the main computer.
Some of the LRU's the seller I bought this from had their electronics gutted by the MOD. Presumably because they were classified.
@@adriansmith31
Most all the documentation (engineering prints, schematics, assembly drawings) we had at the factory had "NATO Unclassified" stamped on them ... there were certain operational parameters of the RADAR electronics that were (and are?) classified.
@@uploadJ That would explain why some LRU's from the Tornado had some or all of the circuit boards missing. Presume they were classified parts or had code in ROMS that was classified.
Hello! Good video! It is as I thought - there are only ferrite toroid transformers/coils - because EE/POT cores are quite fragile for avionics)). What is the thickness of PCB boards in these blocks? Are there 2 millimeters?
Hi I no longer have this unit although I do have one of the PCBs though which I will have to find.
32:00 they are very expensive wet tantalum capacitors.
Nice, thanks. I've watched quite a lot of your videos found them when searching for information on this.
Now they could cram all this stuff on a single IC if they wanted to 😮
Yeah mostly 74 series logic and some analog. All of which could mostly fit onto a single fpga chip nowadays
The German Luftwaffe won't be amused seeing their active inventory being disclosed online. 🤣
It came from an RAF military surplus store. There were some classified units that had their electronics stripped prior to sale. This unit is unclassified, no custom chips nor computer code contained inside.
If this nice box contains a computer, it should have RAM and ROM chips. So no computer, and no CPU of any kind in here.
I did find out more about this unit since the video was made. It is just an interface unit; there are several computers in the aircraft. The flight computer is separate which I found on eBay but it was too expensive to warrant a purchase. This unit sits in the nose behind the radar along with other LRU boxes. It's function is to generate the symbols for the head up display although there is no CPU in there so I suspect that will be in the HUD unit itself.
A bit late to the party. The main computer did not have RAM or ROM chips, the memory was core memory, originally 32 k then 64k. There was no microprocessor either, it had to be radiation hardened, the only microprocessor that was radiation hardened was the Rockwell 1806.
I cannot remember what subsystems were connected through IFU1 and IFU2. The subsystems I can remember are
a)inertial navigation system (INS)
b) secondary attitude and heading reference system (SAHRS),
c) the ground mapping radar,
d) terrain following radar,
e) laser marked target receiver,
f) HUD,
g) Head Down Display repeater,
h) TV Tabs
i) Radar Warning Receiver
j) cockpit voice recorder also used as input for mission data
k) Flight Guidance Control System
l) weapons
m) radar altimeter
Don’t forget that the aircraft was completely fly by wire, with mechanical links as reversionary mode only.
You can have a computer made up of MSI components without having a microprocessor.
Secondly, computers can be analogue and perform computation on continuous quantities and there will typically contain operational amplifier integrated circuits to implement mathematical operations.
So whilst this may not be the case here, your statement is factually incorrect.
That box is the CPU
Central Processing Unit.
The boards within are the Micro Processors.
Its called LSI.
Large Scale Intergration.
You don't need a Computer on an aircraft. Just Process inputs, deliver outputs.
What is confusing, is the integrated redundancies.
Don't forget the Cold War attitudes toward Captured Tech, and Anti Reverse-Engineering.
The Tornado and the Aardvak systems are interchangeable, including the engines.
Happy Ground Hog Day.
@@snakezdewiggle6084 IFU 1 and IFU2 did not have any computing capability, they were basically designed to convert analogue to digital inputs, DC to D.C. level conversion, creating status words from the other equipment etc so that the main computer could access data and status information from the avionics, which was then used to display information on the TV tabs and other inflight displays, and recorded on the crash recorder.
I worked at the MRCA Control, Design and Management Team from 1979 to 1981 in Camberley, Surrey involved with the testing software for the avionics system and Flight Guidance Control System.