Comparing Nimrod MR1 with the Shack MR?
Thread Starter
Comparing Nimrod MR1 with the Shack MR?
http://aeroflt.users.netlink.co.uk/t...rod/nimrod.htm
Says:
“To keep costs down, much of the mission avionics would be similar to that already used in the Shackleton. Designated HS.801, the Comet derivative was offered to meet ASR 381 in July 1964.”
I'd thought that the Nimrod was always planned to have a better radar (Searchwater) and that the ASV21 fit in the MR1 was always viewed as interim.
But how fair is it to compare the rest of the kit?
Presumably the MAD was similar, or even the same, but how about the ESM?
And how about sonics processing and the central computer?
And did the Shack MR2/3 have anything like the same nav kit?
Says:
“To keep costs down, much of the mission avionics would be similar to that already used in the Shackleton. Designated HS.801, the Comet derivative was offered to meet ASR 381 in July 1964.”
I'd thought that the Nimrod was always planned to have a better radar (Searchwater) and that the ASV21 fit in the MR1 was always viewed as interim.
But how fair is it to compare the rest of the kit?
Presumably the MAD was similar, or even the same, but how about the ESM?
And how about sonics processing and the central computer?
And did the Shack MR2/3 have anything like the same nav kit?
I don't own this space under my name. I should have leased it while I still could
Bollocks would be a good word to start with. Complete and utter as useful adjectives.
<<I'd thought that the Nimrod was always planned to have a better radar (Searchwater) and that the ASV21 fit in the MR1 was always viewed as interim.>>
This is true but the Nimrod entered service, with trials, in 1970-71 whereas the Seachwater was about 7 years later.
<<But how fair is it to compare the rest of the kit?>>
The active tracking system was a direct bolt in from the Shackleton - Mk 1c Sonobouys, active and passive, the former with a range of 3500 yards and a slow data rate. Even when introduced it was out moded for modern, and not so modern, nuclears. The passive would work if you could induce the nuclear to cavitate. They were not daft so they would not cavitate unless you got a torpedo close enough to count.
<<Presumably the MAD was similar, or even the same,>>
The Shack did not have MAD and the Nimrod did not have Autolocus.
<<but how about the ESM?>>
The Shack had a joke of an ESM, Orange Harvest, the sparkplug on the top. It could detect and give a bearing for S or X band radar, on a good day with a following wind.
The ARAR/ARAX in the Nimrod was ex-Atlantic and a brilliant piece of kit operated by equally brilliant operators. It was enhanced by the creation of the ESM Data handbook, a database created almost single handed my MAEOp McConnel (may be Connel) at ISK against much opposition from NATO who did not want NATO radar parameters released to the Maritime force.
<<And how about sonics processing>>
The Mk 1c Sonics system and the Jezebel LOFAR systems were integrated into the central computer system to the extent that bearings could be transmitted and displayed. Later software mods allowed the Tac Nav to see which sonobuoys the Wet Team was monitoring. Once this Mod was introduced it was remarkable how often the Wet Team was not monitoring sonobuoys adjacent to the buoy in contact.
<<and the central computer?>>
This owed its lineage to the Chieftain Tank for which an 8k 16-bit computer was adequate. It used core storage - something that Babbage might have recognised - a small wooden frame with sets of parallel wires in a grid. The intersections with a small iron washer. As it was made of iron it was rusty!
<<And did the Shack MR2/3 have anything like the same nav kit?>>
The Shack had Blue Silk/GPI 4/GIVB whereas the Nimrod had Decca 67(?)/Inertial/and a modern compass system. The simple details elude me. The doppler was a bigger version of the type fitted to the Dominie. The IN was a steal from the Blue Steel. Extra panel lighting courtesy of the Lancaster George VI pillar lamps.
Both had Loran as a long range fixing aid but that in the Nimrod was as fitted to the Britannia.
The Nimrod had a Kollesman Sextant that could be used to slew the IN which was not the world's best. The Shack used the Mk 9.
Weapons wise both aircraft used the Mk 30 and Mk 44 torpedoes, carried Lindholme Gear, and 5 inch flares. The Nimrod dropped the Marker Marine through its sonobuoy launcher. Instead of smoke floats the Nimrod was fitted with a Retro Launcher that fired a French made smoke float at aircraft groundspeed. It would fall more or less where the aircraft fired it.
The Mk 30 was a passive torpedo and well obsolete even before it was fitted to the Nimrod. It had a search speed of 12 knots and an atack speed of 18 kts. Most conventionals could outrun it. It was however very quiet and could 'sanitize' an area for 20 minutes.
The Mk 44 was no racing snake either with a noisy search speed of 30 kts. It ran for 6 minutes. Even if it caught its target it is quite likely that it would not have worked as we only got certified and effective fuses shortly before it was withdrawn from service.
<<I'd thought that the Nimrod was always planned to have a better radar (Searchwater) and that the ASV21 fit in the MR1 was always viewed as interim.>>
This is true but the Nimrod entered service, with trials, in 1970-71 whereas the Seachwater was about 7 years later.
<<But how fair is it to compare the rest of the kit?>>
The active tracking system was a direct bolt in from the Shackleton - Mk 1c Sonobouys, active and passive, the former with a range of 3500 yards and a slow data rate. Even when introduced it was out moded for modern, and not so modern, nuclears. The passive would work if you could induce the nuclear to cavitate. They were not daft so they would not cavitate unless you got a torpedo close enough to count.
<<Presumably the MAD was similar, or even the same,>>
The Shack did not have MAD and the Nimrod did not have Autolocus.
<<but how about the ESM?>>
The Shack had a joke of an ESM, Orange Harvest, the sparkplug on the top. It could detect and give a bearing for S or X band radar, on a good day with a following wind.
The ARAR/ARAX in the Nimrod was ex-Atlantic and a brilliant piece of kit operated by equally brilliant operators. It was enhanced by the creation of the ESM Data handbook, a database created almost single handed my MAEOp McConnel (may be Connel) at ISK against much opposition from NATO who did not want NATO radar parameters released to the Maritime force.
<<And how about sonics processing>>
The Mk 1c Sonics system and the Jezebel LOFAR systems were integrated into the central computer system to the extent that bearings could be transmitted and displayed. Later software mods allowed the Tac Nav to see which sonobuoys the Wet Team was monitoring. Once this Mod was introduced it was remarkable how often the Wet Team was not monitoring sonobuoys adjacent to the buoy in contact.
<<and the central computer?>>
This owed its lineage to the Chieftain Tank for which an 8k 16-bit computer was adequate. It used core storage - something that Babbage might have recognised - a small wooden frame with sets of parallel wires in a grid. The intersections with a small iron washer. As it was made of iron it was rusty!
<<And did the Shack MR2/3 have anything like the same nav kit?>>
The Shack had Blue Silk/GPI 4/GIVB whereas the Nimrod had Decca 67(?)/Inertial/and a modern compass system. The simple details elude me. The doppler was a bigger version of the type fitted to the Dominie. The IN was a steal from the Blue Steel. Extra panel lighting courtesy of the Lancaster George VI pillar lamps.
Both had Loran as a long range fixing aid but that in the Nimrod was as fitted to the Britannia.
The Nimrod had a Kollesman Sextant that could be used to slew the IN which was not the world's best. The Shack used the Mk 9.
Weapons wise both aircraft used the Mk 30 and Mk 44 torpedoes, carried Lindholme Gear, and 5 inch flares. The Nimrod dropped the Marker Marine through its sonobuoy launcher. Instead of smoke floats the Nimrod was fitted with a Retro Launcher that fired a French made smoke float at aircraft groundspeed. It would fall more or less where the aircraft fired it.
The Mk 30 was a passive torpedo and well obsolete even before it was fitted to the Nimrod. It had a search speed of 12 knots and an atack speed of 18 kts. Most conventionals could outrun it. It was however very quiet and could 'sanitize' an area for 20 minutes.
The Mk 44 was no racing snake either with a noisy search speed of 30 kts. It ran for 6 minutes. Even if it caught its target it is quite likely that it would not have worked as we only got certified and effective fuses shortly before it was withdrawn from service.
Last edited by Pontius Navigator; 15th Feb 2007 at 16:41.
All things are relative. Yes the Nimrod was a great advance in comfort and range/speed capability when it was introduced, and anything was better than climbing over both mainspars, but initially it was not that big an advance ASW wise.
The ASV 21 was way ahead of anything else when it was introduced, roundabout the time the ASR was written, and in the hands of most of the operators on both the Shack and MR1 really could see the proverbial needle in a haystack - it was therefore not seen as anything that needed changing at the time of initial introduction.
MAD was trialled on the Shack (by ASWDU) but was not particularly successful and would have been quite expensive to modify, whereas very straightforward to put into the new airframe.
The Mk 1c sonar was equally maybe not as good as the kit the US had in the P3, but that didn't stop us catching nukes - ask the boomer captain we caught in the middle of the South China Sea - but again it was the operators who could wring the most out of it. As for processing power and central computer it depended on the size of the hangover or the length of the sortie.
ESM was first generation, but again we made do with what we had and got on with it, and achieved a number of successes, and you could always convince the unwary that the aerial was a stovepipe and the aircraft ran on nutty slack!!
Autolycus was only useful against diesel boats (and was the development of a WW2 system to detect snorting U-boats), and with the threat going to nuke boats was not required (and besides would have been a nightmare to marry to a pressurised fuselage).
The biggest advance was with the nav kit and the tac nav especially - the display on its own was worth the changeover. But again, it was the operators who made the kit work and drove the upgrades to produce the MR2.
The only thing that was degraded was the power of the Mk 1 Eyeball, as fewer positions had a good lookout.
I just think it's a shame the powers that be didn't keep at least one specimen for the RAF Museum (and much as I loved flying it it was a museum piece) or Cosford. Even more so at Cosford as we delivered 2 or 3 there for the Tech School, but they were scrapped as the museum was building up.
Edited to cover PN's edit!
You forgot to mention the Depth Charges on the Shack - some great bangs for your buck but as rusty as hell, the ability to carry 1000lb bombs on the internal security role - 21 of them and used to some effect in Aden/the Radfan, and a very large bucket of sunshine, although the 'escape manoeuvre' after dropping left a bit to be desired! I agree about the Mk 30, and a runaway in the air was more than a little frightening, but the Mk 44 was a great advance on what went before, and (AFAIK) was only introduced into US service in the late 60's as well. There were a number of other things we carried at various times that have also gone from the corporate memory, but we did have something that the Nimrod didn't have - 2 x 20mm Hispano's with plenty of ammunition and really effective to use. Come to think of it that's better than the Typhoon as well!
Oh, and the galley was a lot more cosy, and the bunk beds (and the bomb aimers cushion) were really comfortable on those long sorties.
The ASV 21 was way ahead of anything else when it was introduced, roundabout the time the ASR was written, and in the hands of most of the operators on both the Shack and MR1 really could see the proverbial needle in a haystack - it was therefore not seen as anything that needed changing at the time of initial introduction.
MAD was trialled on the Shack (by ASWDU) but was not particularly successful and would have been quite expensive to modify, whereas very straightforward to put into the new airframe.
The Mk 1c sonar was equally maybe not as good as the kit the US had in the P3, but that didn't stop us catching nukes - ask the boomer captain we caught in the middle of the South China Sea - but again it was the operators who could wring the most out of it. As for processing power and central computer it depended on the size of the hangover or the length of the sortie.
ESM was first generation, but again we made do with what we had and got on with it, and achieved a number of successes, and you could always convince the unwary that the aerial was a stovepipe and the aircraft ran on nutty slack!!
Autolycus was only useful against diesel boats (and was the development of a WW2 system to detect snorting U-boats), and with the threat going to nuke boats was not required (and besides would have been a nightmare to marry to a pressurised fuselage).
The biggest advance was with the nav kit and the tac nav especially - the display on its own was worth the changeover. But again, it was the operators who made the kit work and drove the upgrades to produce the MR2.
The only thing that was degraded was the power of the Mk 1 Eyeball, as fewer positions had a good lookout.
I just think it's a shame the powers that be didn't keep at least one specimen for the RAF Museum (and much as I loved flying it it was a museum piece) or Cosford. Even more so at Cosford as we delivered 2 or 3 there for the Tech School, but they were scrapped as the museum was building up.
Edited to cover PN's edit!
You forgot to mention the Depth Charges on the Shack - some great bangs for your buck but as rusty as hell, the ability to carry 1000lb bombs on the internal security role - 21 of them and used to some effect in Aden/the Radfan, and a very large bucket of sunshine, although the 'escape manoeuvre' after dropping left a bit to be desired! I agree about the Mk 30, and a runaway in the air was more than a little frightening, but the Mk 44 was a great advance on what went before, and (AFAIK) was only introduced into US service in the late 60's as well. There were a number of other things we carried at various times that have also gone from the corporate memory, but we did have something that the Nimrod didn't have - 2 x 20mm Hispano's with plenty of ammunition and really effective to use. Come to think of it that's better than the Typhoon as well!
Oh, and the galley was a lot more cosy, and the bunk beds (and the bomb aimers cushion) were really comfortable on those long sorties.
Last edited by Shackman; 15th Feb 2007 at 17:26.
An important difference was that the Jezebel system, although trialled by ASWADU, was not fitted operationally to the Shackleton. That gave the Nimrod MR an passive acoustic search capability which the Sackleton did not possess.
Mk 30 may have been the secondary weapon in the inventory but only until the Mk 46 became available. Anyone recall the in service date?, probably around 1974/5.
and as such was only intended as a short term source in the localisation and attack phase. But we all know that it in fact it performed much better than that. Although it could lead the unwary astray! Omega was fitted later, circa 1978?
The other big advantage which the Nimrod conferred was the capability to reduce the time late at datum, by virtue of its higher speed.
YS
Weapons wise both aircraft used the Mk 30 and Mk 44 torpedoes
The IN was a steal from the Blue Steel
The other big advantage which the Nimrod conferred was the capability to reduce the time late at datum, by virtue of its higher speed.
YS
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Shackman,
Don't know when Cosford got rid of the Mk3 phase 3s. When I was training there in the early 80s had lots of fun climbing over the main spars with the test kits for the avionics and having a little sleep in the back after a big night out in Wolverhampton
Don't know when Cosford got rid of the Mk3 phase 3s. When I was training there in the early 80s had lots of fun climbing over the main spars with the test kits for the avionics and having a little sleep in the back after a big night out in Wolverhampton
I don't own this space under my name. I should have leased it while I still could
The Mk 30 was secondary only in that it was displaced by the Mk 46. In an attack both 30 and 44 could be dropped. Regarding the Mk 44, just before it left service there were two trials to see if the fuses worked. The first was a fiasco as the wepaons were sabotaged by the workers. The depot was closing and they were losing their jobs - they left the seals off. The second trial was 100% successful and the first time that the warheads had gone bang, as far as I can recall.
The stock level was 100 Mk 30s and 200 Mk 44s. Given a load out of 6 torpedos that gave 50 ship sets - given a planned buy of 46 ac that did n't leave many spares.
With the advent of the Mk 46 the buy was for 300 but the 44s were retained for a time thus giving 80 or so ship sets but still less than the number of potential targets.
The Stingray buy was also initially additive to the 46s.
IIRC the in-service date for the 46 was a little later, probably nearer 76-77. Stingray trials were on-going 79-80.
The stock level was 100 Mk 30s and 200 Mk 44s. Given a load out of 6 torpedos that gave 50 ship sets - given a planned buy of 46 ac that did n't leave many spares.
With the advent of the Mk 46 the buy was for 300 but the 44s were retained for a time thus giving 80 or so ship sets but still less than the number of potential targets.
The Stingray buy was also initially additive to the 46s.
IIRC the in-service date for the 46 was a little later, probably nearer 76-77. Stingray trials were on-going 79-80.
Shacks from Cosford, WR974 & WR982 were moved in 1988 to Peter Vallance collection, Charlwood, Surrey now Gatwick Aviation Museum, where they both can be seen on display. And it's still "fun" climbing over the spars, just takes a bit longer these days!
The only real modification to ASV21 (ASV21D on Nimrod) was the bearing and range unit which replaced the original marker bearing unit and the range control on the indicator, this provided the A to D for input into the Elliot 920D interface.
It was amazing what that computer did with just 8K of ferrite core memory!
http://www.gatwick-aviation-museum.co.uk
The only real modification to ASV21 (ASV21D on Nimrod) was the bearing and range unit which replaced the original marker bearing unit and the range control on the indicator, this provided the A to D for input into the Elliot 920D interface.
It was amazing what that computer did with just 8K of ferrite core memory!
http://www.gatwick-aviation-museum.co.uk
I don't own this space under my name. I should have leased it while I still could
The other bit of Nimrod nav kit I should mention is the RDD or Route Dynamic Display (IIRC). This was a bit of kit, slaved to the nav system, that would shine an arrow on to the Route Nav's table. It had map scales of 1:500000 for tactical work and 1 mil and 2 mil for route flying.
Initially for route work we used skeleton lamberts plotting charts but we had to join 4 charts together to cover ISK and the Norge Sea.
Eventually we switched to AIDU en route charts. Now Kinloss and airfields to the north meant the en route chart was rather large so AIDU reduced it to 1:2.5 mill and it was as much use to us as a chocolate tea pot. After entreaties to them they produced a 2 mill version with slightly less geographic cover.
As the projected arrow crawled over the chart the RNav simply had to dot and time the arrow to plot the track history or plot sonobouy positions as they were dropped. It the Tac system crashed there was enough plotted data to continue a prosecution.
As submarines tend to move slowly, 200-300 yards a minute, it followed that we would be flying in small circles on the chart. For that reason we used tracing paper overlays and would replace them as each become too complex.
We had a plot technique to mark when the radar was on or off. Post flight it would be possible to analyse the areas covered by radar and the re-visit frequency.
The Shack had a similar system as far as IIRC form the AEW Shack. For Mk 1c Sonics however I was told they used to place lighthouses on the table!
Initially for route work we used skeleton lamberts plotting charts but we had to join 4 charts together to cover ISK and the Norge Sea.
Eventually we switched to AIDU en route charts. Now Kinloss and airfields to the north meant the en route chart was rather large so AIDU reduced it to 1:2.5 mill and it was as much use to us as a chocolate tea pot. After entreaties to them they produced a 2 mill version with slightly less geographic cover.
As the projected arrow crawled over the chart the RNav simply had to dot and time the arrow to plot the track history or plot sonobouy positions as they were dropped. It the Tac system crashed there was enough plotted data to continue a prosecution.
As submarines tend to move slowly, 200-300 yards a minute, it followed that we would be flying in small circles on the chart. For that reason we used tracing paper overlays and would replace them as each become too complex.
We had a plot technique to mark when the radar was on or off. Post flight it would be possible to analyse the areas covered by radar and the re-visit frequency.
The Shack had a similar system as far as IIRC form the AEW Shack. For Mk 1c Sonics however I was told they used to place lighthouses on the table!
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The Nimrod RDD was indeed very similar to the Shack system (GPI 1??). The lighthouses went under the translucent table such that their beams were projected up onto the plotting surface.
Bob C
Bob C
I don't own this space under my name. I should have leased it while I still could
Stratia I accept your apology.
I used to admire the tomatoes in Stage 2 so I do know about those lighthouses too.
My 1st Nav was the hairy Shacklebombergator.
The other 'legacy' call was IIRC, Scanner to Attack. Always called to confuse the uninitiated.
I used to admire the tomatoes in Stage 2 so I do know about those lighthouses too.
My 1st Nav was the hairy Shacklebombergator.
The other 'legacy' call was IIRC, Scanner to Attack. Always called to confuse the uninitiated.
I don't own this space under my name. I should have leased it while I still could
Apart from the three racks of DCs in the foreground the two torpedoes are a Mk 44, front and a Mk 30, rear.
I still say we could have had twice as many Atlantiques at half the price of the Nimrod.
I don't own this space under my name. I should have leased it while I still could
Yes, the saving for only having to buy half as many engines per aircraft.
The RDD was used as attack "reversionary mode" when the Tac display failed - the attack charts were straight from the Shack.
In the Med in summer, and the Indian Ocean, unpressurised at low-level, the a/c often couldn't cope with cooling the tac system and it would crash with monotonious regularity - the route nav would be a busy boy...
The original Nimrod Tac Manual also included the instruction to wear your bonedome when in the nose - presumably to protect your head as the radar smashed into the back of it.... (and yeah, I know why the instruction was still there.....
)
In the Med in summer, and the Indian Ocean, unpressurised at low-level, the a/c often couldn't cope with cooling the tac system and it would crash with monotonious regularity - the route nav would be a busy boy...
The original Nimrod Tac Manual also included the instruction to wear your bonedome when in the nose - presumably to protect your head as the radar smashed into the back of it.... (and yeah, I know why the instruction was still there.....
)
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Atlantique vs Nimrod et al
Croqueteer,
No experienced Maritime aviator (or aviatrix) would willingly fly at low level over the ocean on a two-engined aircraft. The Dutch Navy had two Atlantiques ditch, they then changed to P3 Orions. Had it not been for the two auxiliary jet engines on the SP2H (P2V7) my crew would have been surviving in our dinghies in the Coral Sea instead of being safely ashore, toasting Mr Westinghouse, following the spectacular failure of one of our two 3,500 HP main powerplants.
Flight Safety comes at a price - Beancounters please take note!
No experienced Maritime aviator (or aviatrix) would willingly fly at low level over the ocean on a two-engined aircraft. The Dutch Navy had two Atlantiques ditch, they then changed to P3 Orions. Had it not been for the two auxiliary jet engines on the SP2H (P2V7) my crew would have been surviving in our dinghies in the Coral Sea instead of being safely ashore, toasting Mr Westinghouse, following the spectacular failure of one of our two 3,500 HP main powerplants.
Flight Safety comes at a price - Beancounters please take note!
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er - I am an experienced maritime aviator spanning Shack days and the start of Nimrod. I backed the Atlantique from the start, I would happily trust two Tynes, although all my subsequent flying was on Viscounts and the 146! Most people fly the Atlantic on two nowdays. I remember one Dutch ditching (?) all survived, but I can't recall the second. They did fly one into Jan Mayen island, but you can't blame that on the engines. The Atlantique is a purpose built maritime aircraft, and very good at it. Time on task is the name of the game, and if I remember correctly, a Nimrod had to transit over 500 miles before it could beat the Shack at time on task. I'm not knocking the Nimrod, but we have spent , and are still spending, a horrendous amount of money on it, but that's defence procurement for you.