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Sea Harrier & Gr3 Nav / Attack

Adam106

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I’m particularly interested in the navigation and attack capabilities of the early Harriers, in particular Falklands era. However research on the net has only led to a partial understanding of this subject. It’s the same story with published works.
I’m aware that some members of the forum are knowledgable about this subject and I wonder if anyone could fill some of the gaps in my knowledge? Hopefully none of the answers will breach any security concerns etc….

If we start with the Sea Harrier:
The SHAR used the Ferranti 1010? navigation system and Smiths HUDWAC – not a pure inertial system due to ship board use, my questions are;
1) Did the SHAR FRS. 1 have CCIP / CCIL modes for bombing? The HUDWAC software provided weapon-aiming cues for Air to Air, but what was available Air to Ground? Both Ward’s and Morgan’s books make reference to depressed sightline attacks (DSL) with pre calculated depression angles for manual bombing. No mention is made of CCIP, which leads you to think it wasn’t available. The question is why? The aircraft had a pretty accurate nav system with Doppler, which could provide data like wind vectors etc needed for CCIP.
2) If it had CCIP, did the system have a Planned Attack / Laydown mode? – Designating a waypoint as the target then carrying out a computer-assisted attack. Ward mentions in his book that 801 sqn SHARs performed laydown attacks at high altitude using a manual pre calculated release distance from the current waypoint – very much an ad hoc technique. So did the SHAR not have a computed planned attack mode?
3) The SHAR defiantly had a LOFT / TOSS capability – mention is made of this in numerous sources. This would have needed a radar lock on, of a surface ship for example, with the HUDWAC providing the required pull up and release cues. This capability was no doubt originally intended for its nuclear strike role – lobbing WE177s at ships. Can anyone confirm this and provide more detail? What did the pull up symbology look like? – Was it similar to the Tornado’s?
4) Other sources I have mention 3 Air to Surface bombing (ASB) modes; ASB1, ASB2 and ASB3;
ASB1 – basic manual bombing with depressed sightline – fine understood
ASB2 – computer assisted bombing, ‘which accounts for height, speed, altitude and wind speed’ – Is this referring to CCIP? This source comes from the mid nineties- was CCIP an upgrade to the FRS.1 that took place after 1982 maybe– a possible reason for no mention in Wards book????
ASB3 – Computer assisted bombing with radar ranging – using the Blue Fox to radar range the target to provide a more accurate calculated release point. Good, I understand the concept – can anyone confirm and provide details of HUD symbology etc?
I don't imagine there were buttons for ASB1, ASB2 etc in the cockpit - these merely being configurations of the system that required setting up. There were no doubt other reversion modes as well.

Now for the Harrier GR3:
The GR3 used the Ferranti FE 541 inertial attack system – an early (analog?) INS system, which was ahead of its time in 1969 but often said to be too complicated for the aircraft it was put into…. I know CCIP / Planned attack etc is irrelevant for the Falklands since it wasn’t available due to problems aligning the FE 541 on board ship.

However the GR3 had a sophisticated system for both planned and target of opportunity attacks. Some of the HUD symbology can be seen here:
http://www.flightglobal.com/pdfarchive/view/1971/1971%20-%200108.html

Clearly the GR3 was capable of computer assisted planned attacks on known locations, but again, was there a CCIP mode? I ask because there seems to be no ‘release cue’ present on the bomb fall line. This was a short little line that would rise up to meet the ‘target bar’ (the one aligned over the target), when the two lines met the bombs would release automatically. The little ‘release cue’ represented I think a CCIP solution – at least it does on the Jaguar for which I have a NAV / ATTACK Brochure produced by British Aerospace. Now the HUD symbology for both the Harrier and Jaguar look very similar (both made by Smiths), so without the ‘release cue’ I ask the question did the Gr3 have CCIP for bombs? Again there seems to be no specific mention of it in my research.

Does anyone own or has seen this manual:
http://www.flight-manuals-on-cd.com/AV8.html - CD 2 ‘Manufacturers Pilot's Notes for the Harrier GR.Mk.1, HSA Publication No 25 dated 2-12-71 with approx 196 pages.’
Does it contain any further information on the navigation / weapons system?

Sorry, it’s been a longer post then intended but for some reason I’m intrigued by this stuff. Maybe someone can help fill in the gaps……

Adam.
 

JFC Fuller

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This thread may be of interest to you in places: http://www.secretprojects.co.uk/forum/index.php/topic,12803.0.html
 

Adam106

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sealordlawrence said:
This thread may be of interest to you in places: http://www.secretprojects.co.uk/forum/index.php/topic,12803.0.html

Yes, thanks, I've seen that thread. Some good snippets about FE541 but lacking some of the detail I'm after.
 

JFC Fuller

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Adam,


I will have to look through my notes to see what else I have noted down over the years, but here are some snippets that I have found, most of which you probably already know.


SHAR did not use FIN1010 (That was the Tornado system), they were related but only loosely. The FIN1040 used the same platform as the rest of the FIN1000 series but only had two dry gyros instead of three floating gyros (it also had a larger 64,000 word computer), apparently it also performed fuel management. It was called the Navigation Heading and altitude reference system (NAVHARS) and had 10 waypoints. Confusion may have come about because the FLIR in the nose of the GR7 was the GEC-Marconi 1010. The HUD was a Smiths product and there was a Decca 72 doppler radar alongside an autopilot.


The SHAR was a fleet defence fighter and Blue Fox was derived from Seaspray (designed as a sea surface search radar) and the weapons aiming computer was designed to track moving surface targets (ships) and for most of its life the SHAR had no other way of attacking ships (Sea Eagle was integrated) so tossing WE177's is probably it, Toss bombing is confirmed this excellent overview of Sea Harrier avionics here:


http://www.flightglobal.com/pdfarchive/view/1976/1976%20-%200049.html (continued the next page) You may also be interested in this:


http://www.flightglobal.com/pdfarchive/view/1972/1972%20-%201476.html


As a continuation of speculation, given the original intended role of the SHAR (small numbers deployed as mid-Atlantic fleet defence fighters- kind of like a lightweight Blackburn Firebrand) and the fact that the nav-attack system had already been scaled back to what it was from a full inertial system that had been planned originally I would suggest that any land attack capability was highly limited to start with.


Re GR.3, a system called Finrae was used during the Falklands (rapid alignment equipment), this was supposedly based on Navhars and was used to isolate the GR.3 full inertial platform during deck operations- did not work very well.
 

Adam106

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Yeah thanks, I've seen the first of those flight global articles, but not the second. Interesting.

I was typing from memory with the FIN 1010 thing, so I'm not surprised I got that one wrong.

Zoom into the picture of the HUD control panel in the first link you gave and you can see that the HUD modes are listed as: V/STOL, Lnch, Gen, A/A, Toss and Rev.

I guess Lnch is missile (Aim-9) launch,
Gen - General (navigation??),
A/A - Air to Air - Guns mode maybe, with Continuously Computed Impact Line, since missiles would presumably be fired in Lnch mode?
Rev - HUD would maybe show reversionary data, ie basic heading and attitude information from the master gyro without NAVHARs processing (or a from standby attitude indicator?)
Toss - Toss Bombing - Can we differentiate between TOSS and LOFT? Are they one and the same?
V/STOL - Provides a turn and slip ball type indicator for hovering and transitional flight at the bottom of the HUD, with maybe nozzle position?
There also seems to be a standby sight option – just a reticule, probably depressible in the event of HUD computer failure.

Alas no CCIP or ‘planned’ mode is evident here – I think you’re assessment of the Sea Harriers intended role and original numbers (3 operational Squadrons with 5 aircraft each, I think) might mean the Attack capabilities were indeed limited, at least in the early eighties. The only way to know for sure would be first hand evidence from air crew or an engineer I guess. There's not much else out there.....
 

newboy1

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The FE 541 INAS was fitted to Harrier GR1 and GR3. The USMC AV8A was fitted with the same system as the GR1 so that HSA publication you mention probably has all you need to know about the weapons modes and HUD symbology from a Pilot's perspective (although in 1971 the whole mode suite may not have been fully developed). It did have an Unplanned Attack mode which was probably the closest to a CCIP solution. I seem to remember it generated a fixed "target bar" on the bomb fall line which represented a crosswind-compensated release solution for the weapon chosen/attack altitude etc. There certainly wasn't a "release cue" as used for Planned Attacks. Your description of the Target Bar and Release Cue interaction is correct for a Planned Attack except that the Release Cue was driven by "time to go" - when it hit the Target Bar, time to go was 0, and the weapons were released. The system could be set to release a stick of bombs, and in that case the Release Cue would appear to bouce repeatedly off the Target Bar.

The Harrier and Jaguar HUD symbology was almost identical because they both used the same units by Smiths. The earliest versions of INAS were purely analogue, but some of the GR3 LRUs were upgraded in the late 1970s to add digital circuitry to the Weapon Aiming side.

Adam106 said:
I’m particularly interested in the navigation and attack capabilities of the early Harriers, in particular Falklands era. Now for the Harrier GR3:
The GR3 used the Ferranti FE 541 inertial attack system – an early (analog?) INS system, which was ahead of its time in 1969 but often said to be too complicated for the aircraft it was put into…. I know CCIP / Planned attack etc is irrelevant for the Falklands since it wasn’t available due to problems aligning the FE 541 on board ship.

However the GR3 had a sophisticated system for both planned and target of opportunity attacks. Some of the HUD symbology can be seen here:
http://www.flightglobal.com/pdfarchive/view/1971/1971%20-%200108.html

Clearly the GR3 was capable of computer assisted planned attacks on known locations, but again, was there a CCIP mode? I ask because there seems to be no ‘release cue’ present on the bomb fall line. This was a short little line that would rise up to meet the ‘target bar’ (the one aligned over the target), when the two lines met the bombs would release automatically. The little ‘release cue’ represented I think a CCIP solution – at least it does on the Jaguar for which I have a NAV / ATTACK Brochure produced by British Aerospace. Now the HUD symbology for both the Harrier and Jaguar look very similar (both made by Smiths), so without the ‘release cue’ I ask the question did the Gr3 have CCIP for bombs? Again there seems to be no specific mention of it in my research.

Does anyone own or has seen this manual:
http://www.flight-manuals-on-cd.com/AV8.html - CD 2 ‘Manufacturers Pilot's Notes for the Harrier GR.Mk.1, HSA Publication No 25 dated 2-12-71 with approx 196 pages.’
Does it contain any further information on the navigation / weapons system?
Adam.
 

newboy1

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thinking about it again, the GR3 incarnation of the INAS also interfaced with the (Ferranti) Laser Ranger and Marked Target Seeker (LRMTS). I think there was an LR CCIP mode but I'm not sure it was ever tested/proven.
 
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