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#161
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In article ,
Guy Alcala writes: Peter Stickney wrote: As a somewhat side note. I have some doubts about the reputation of the Lancaster II wrt having a lower ceiling than the Lanc I/III. The power available at height isn't really all that much different, and you don't see a similar disparity, (or, for that matter, an absolute difference) between the Merlin-powered Halifaxes (Which used the same engine as the Lanc I), and the Herculese engined aircraft. (Which used the same engine as the Lanc II). What I'd like to know is if the Mk. IIs _really_ had a lower MTOW (63 vs. 65,000) than the Merlin jobs, as virtually every reference states. I've never understood the reason for this. I've wondered if the longer bomb bay might have been a factor in decreasing the structural strength, but some Merlin-engined models also had that, so that's out. The other thought I had was that the Hercules engines were significantly heavier and may have somehow put more stress on the wings, but neither theory seems all that likely. From what I've been able to dig up, the Max Weight of teh Merlin engined lancasters was determined by 1-engine out Rate of Climb on takeoff. Merlin XX airplanes had a Max Weight of 61,500, Merlin 22 airplanes had this raised to 63,000#, and Merlin 24 airplanes were limited to 68,000#, fir regular aircraft, and 72,000# on the Grand Slam carriers. I doubt that it was a strength issue. The Lancaster center section was virtually unchanged in the Lincoln, which tipped the scales at 82,000#, and the Shackleton, which was somewher on the order of 100,000#. Re the Merlin vs. Hercules Halifaxes, don't forget that the latter had another 6 feet (IIRR) added to the wingspan (and a commensurate increase in area), as well as having the nose considerably cleaned up I've nearly rebuilt my analysis tools that were lost when that hard drive failed (And don't lecture me on backups - the lack of restorable backups was part of the trigger for the upgrade in the first place. Sometimes cascading failures can fork you over real good), adn I'll make the Lancs II and Lanc III my test cases. We'll see how Historical References stack up against the Fundamentals of Werodynamics. Please do. In process, results as soon as I have them. It wouldn't be the first time that the accepted references are repeating bogus data. For example, I see the incorrect numbers for the Merlin XX-23 series that were published in the '45-'46 _Jane's_All_the_World's_Aircraft repeated all over the place. That's why I wonder about the Lanc II's MTOW. It seems more likely to me that the lower weight refers to an earlier version, and was probably increased later, but someone (Green, for a bet) had the specs for an earlier version of the Mk. II, but those for later versions of the Merlin-engined varieties. SOmebody must have a Pilot's Handbook for the thing. -- Pete Stickney A strong conviction that something must be done is the parent of many bad measures. -- Daniel Webster |
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#164
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In article , Dave Eadsforth
writes Take off and straight flying...........................63,000 lbs (For Lancaster ASR MkIII...............................64,000 lbs (For aircraft with Mod 503 or 518 Mod 588 or 598 Mod 811 or SI/RDA 600 and Mod 1004..65,000 lbs (For aircraft fitted with Merlin 24 or 224, paddle-type blades, Lincoln-type undercarriage, and Mod 1195 tyres, and only to be used on runways....72,000 lbs Anybody know what the MTO was on the aircraft used for the Tirpitz missions from Lossiemouth? I believe they swapped the engines out for Merlin 24s 'borrowed from other units a better description'. The extra fuel they added left them 2 tons over MTO according to Brickhill in the Dam Busters, although there's no mention of the actual weight or MTO referred to (although I suspect one of the earlier lighter weights). -- John |
#165
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The Revolution Will Not Be Televised wrote:
On Mon, 4 Aug 2003 00:27:40 -0400, (Peter Stickney) wrote: snip The difference in horsepower performance at height between a XX series Merlin and a VI/XVI series Hercules wasn't all that great. I'll have hard nimbers for you tomorrow. Please do not lower the tone of usenet discourse by injecting facts into the debate. The last week has given me time to order and read Middlebrook's "The Battle of Hamburg" and "The Berlin Raids," both full of good info re loads. Here's some typical bomb and fuel loads he gives for the first raid on Hamburg, from the former book: Lanc I and III: 9,840 - 13,280 lb., 1,600 (presumably Imperial) gallons. Lanc II: 7,600 - 9,200 lb., 1,700 gallons. Halifax II and V: 5,960 - 7,960 lb., 1,775 gallons. Stirling I and III: 4,788 - 5,136 lb., 1,875 gallons. Wellington X: 2,640 - 4,000 lb., 900 gallons. This first raid had a track distance of 980 (1 Gp.) to 1,020 (6 Gp.) miles depending on the Group, fairly direct routing. The Lanc IIs were in 3 and 6 Groups. The extra fuel weight carried by the Lanc IIs (poorer mpg) amounts to 720 lbs., which is considerably less than the difference in bombload weights, implying that the remainder of the difference was due to a need to improve the ceiling to equal the Merlin Lancs, and/or a difference in MTOW. "The Berlin Raids" contains a statement by a pilot mentioning that the (Merlin, IIRR) Lancs had their MTOWs increased from 63 to 65,000 lb. during that period (i.e. post-Hamburg). I'll need to find it again. What is also interesting are the stats Middlebrook provides for the Battle of berlin, wherein the loss rates of different heavy bomber types are inversely proportional to their operating ceilings: Lancaster, 5.2%. Halifax, 7.7%. Stirling, 13.2%. Oh, with reference to Pete's and my attempt to redesign the Lanc (and Bomber Command) for day use a few years back at the order of Air Chief Marshal "Butch" Kramer, and how long the process was likely to take starting from the fall of 1943 ("Butch" was loathe to accept our estimate of 6 months minimum to convert enough a/c to high-altitude engines to supply a single squadron, with a year more likely for an entire group with all the other mods needed), serendipitously Middlebrook includes the following (pg. 96): "But the [PRO] contains an interesting correspondence concerning a request made by Bomber Command for six special Lancasters, one for each of the Pathfinder heavy squadrons, to be used by future Master Bombers. The date of the first letter is 24 September 1943. The request was for a Lancaster with uprated Merlin engines which could fly higher than existing types, presumably to allow the Master Bomber to circle the target safely above the bomber force. Initially, Lancaster Mark IVs were expected, but the best that could be managed were Mk. Is fitted with Merlin 85 engines [Guy note: Packard-built, equivalent to the R-R Merlin 68, i.e the V-1650-3]. an initial delivery date of the first aircraft to Rolls-Royce at Hucknall for final modification before handing over to the Pathfinders was given as 15 November -- again just in time for the late November non-moon bombing period -- with the other five aircraft arriving at regular intervals up to the end of February. In fact, the first aircraft did not arrive at Hucknall until 5 December, and then required a further six weeks of work before it was delivered to the Pathfinders, eventually arriving in time for the last raid of the Battle of Berlin [Guy Note: 24/25 March 1944]." Again, I'm not too certain about the published numbers for the Lanc II. I've seen figures bandies about that just don't add up, such as below the critical altitude of the high speed blower. Something's fishy. I haven't seen any auw figures for the III over time, just what was given in early 1943. I suspect they would have gone up over time, just like the B.I/III weights did. I thought a direct comparison with the Halifax III might have been useful, bearing in mind airframe differences. snip Interestingly enough, "The Berlin Raids" states that the Halifax IIIs (after the II/Vs had all been removed from Berlin missions) still had a higher loss rate than the Lancs. I'm looking for the exact quote, but I think this was true regardless of Lanc type. Guy |
#166
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In article ,
Dave Eadsforth writes: In article , Peter Stickney writes In article , Guy Alcala writes: It wouldn't be the first time that the accepted references are repeating bogus data. For example, I see the incorrect numbers for the Merlin XX-23 series that were published in the '45-'46 _Jane's_All_the_World's_Aircraft repeated all over the place. That's why I wonder about the Lanc II's MTOW. It seems more likely to me that the lower weight refers to an earlier version, and was probably increased later, but someone (Green, for a bet) had the specs for an earlier version of the Mk. II, but those for later versions of the Merlin-engined varieties. SOmebody must have a Pilot's Handbook for the thing. I have not been following this part of the thread with any concentration to date, but hope the following might help: From Pilot's Notes dated May 1944 but reprinted April 1945. Maximum weights Take off and straight flying...........................63,000 lbs (For Lancaster ASR MkIII...............................64,000 lbs (For aircraft with Mod 503 or 518 Mod 588 or 598 Mod 811 or SI/RDA 600 and Mod 1004..65,000 lbs (For aircraft fitted with Merlin 24 or 224, paddle-type blades, Lincoln-type undercarriage, and Mod 1195 tyres, and only to be used on runways....72,000 lbs Thanks, Dave. But I should have been more explicit. The Merlin engined Lancs are fiarly consistantly documented. The one that seems off is the Hercules powered Lancaster II. There's been a lot of stuff published about it that doesn't make sense, and an accurate context for the numbers that do exist is hard to come by. Interesting bit about the "Lincoln-Type" landing gear, though. The numbers that you've posted also explain why some sources are off. They seem to be quoting the number for the modified aircraft. -- Pete Stickney A strong conviction that something must be done is the parent of many bad measures. -- Daniel Webster |
#167
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Peter Stickney wrote:
In article , Dave Eadsforth writes: In article , Peter Stickney writes In article , Guy Alcala writes: It wouldn't be the first time that the accepted references are repeating bogus data. For example, I see the incorrect numbers for the Merlin XX-23 series that were published in the '45-'46 _Jane's_All_the_World's_Aircraft repeated all over the place. That's why I wonder about the Lanc II's MTOW. It seems more likely to me that the lower weight refers to an earlier version, and was probably increased later, but someone (Green, for a bet) had the specs for an earlier version of the Mk. II, but those for later versions of the Merlin-engined varieties. SOmebody must have a Pilot's Handbook for the thing. I have not been following this part of the thread with any concentration to date, but hope the following might help: From Pilot's Notes dated May 1944 but reprinted April 1945. Maximum weights Take off and straight flying...........................63,000 lbs (For Lancaster ASR MkIII...............................64,000 lbs (For aircraft with Mod 503 or 518 Mod 588 or 598 Mod 811 or SI/RDA 600 and Mod 1004..65,000 lbs (For aircraft fitted with Merlin 24 or 224, paddle-type blades, Lincoln-type undercarriage, and Mod 1195 tyres, and only to be used on runways....72,000 lbs Thanks, Dave. But I should have been more explicit. The Merlin engined Lancs are fiarly consistantly documented. The one that seems off is the Hercules powered Lancaster II. There's been a lot of stuff published about it that doesn't make sense, and an accurate context for the numbers that do exist is hard to come by. Interesting bit about the "Lincoln-Type" landing gear, though. I believe that applied to the "Specials" for Grand Slam (and probably Tallboy as well), and no others. The weight's right. The numbers that you've posted also explain why some sources are off. They seem to be quoting the number for the modified aircraft. I'm still trying to find the quote in Middlebrook, but IIRR one senior pilot mentioned that the MTOW was boosted from 63,000 to 65,000 during the Battle of Berlin, and the implication I took away (possibly wrong) was that the boost was purely a paperwork okay, rather than one involving airframe strengthening. The latter mods probably came along afterwards. Once I find the quote I'll be able to confirm or deny. Guy |
#168
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On Tue, 05 Aug 2003 02:24:43 GMT, Guy Alcala
wrote: The last week has given me time to order and read Middlebrook's "The Battle of Hamburg" and "The Berlin Raids," both full of good info re loads. Here's some typical bomb and fuel loads he gives for the first raid on Hamburg, from the former book: Good books, and it's worth getting the other two in the series (Peenemunde and Nuremburg Raids), but there is the odd good-faith discrepancy, due I suspect to Squadron ORBs and aircrew logs varying for some reason from Group returns to BC HQ and the subsequent BC raid reports. difference in MTOW. "The Berlin Raids" contains a statement by a pilot mentioning that the (Merlin, IIRR) Lancs had their MTOWs increased from 63 to 65,000 lb. during that period (i.e. post-Hamburg). I'll need to find it again. I remember that: I think this was 1 Group again. Oh, with reference to Pete's and my attempt to redesign the Lanc (and Bomber Command) for day use a few years back at the order of Air Chief Marshal "Butch" Kramer, and how long the process was likely to take starting from the fall of 1943 ("Butch" was loathe to accept our estimate of 6 months minimum to convert enough a/c to high-altitude engines to supply a single squadron, with a year more likely for an entire group with all the other mods needed), serendipitously Middlebrook includes the following (pg. 96): I don't think two-stage merlin production was sufficient until well intop 1944 for seriously considering two-stage engines for production Lancasters en mass. They were too badly needed for Mustangs, Spitfires and Mosquitos first. "But the [PRO] contains an interesting correspondence concerning a request made by Bomber Command for six special Lancasters, one for each of the Pathfinder heavy squadrons, to be used by future Master Bombers. Yes, and I believe these became Lanc VIs subsequently. They weren't used particularly heavily, so far as I can see, and there was no effort to replace them over time, although they would seem like a good idea. I suspect PFF abandoning the Master Bomber technique on big area raids (see Middlebrook's comments on the early Berlin raids which had allocated Master Bombers) immediately after they appeared had something to do with this. an initial delivery date of the first aircraft to Rolls-Royce at Hucknall for final modification before handing over to the Pathfinders was given as 15 November -- again just in time for the late November non-moon bombing period -- with the other five aircraft arriving at regular intervals up to the end of February. In fact, the first aircraft did not arrive at Hucknall until 5 December, and then required a further six weeks of work before it was delivered to the Pathfinders, eventually arriving in time for the last raid of the Battle of Berlin [Guy Note: 24/25 March 1944]." This would tie in with Saward's hi-jacking of six H2S Mk III sets from Coastal Command, although I think the Lanc VIs arrived too late to be considered for fitting the radar too, and they ended up in Lanc IIIs instead. Interestingly enough, "The Berlin Raids" states that the Halifax IIIs (after the II/Vs had all been removed from Berlin missions) still had a higher loss rate than the Lancs. I'm looking for the exact quote, but I think this was true regardless of Lanc type. It may well be true, but overall loss rates for the war for the B.III were significantly less than the B.II and V versions and even better than the Lancs according to Bingham's book on the Halifax. Of course, the level of resistance would affect this, but the IIIs were active in the end of 43 and throughout 44 when casualties were high enough to give them a valid comparison to the Lancs on the same raids. Gavin Bailey -- "...this level of misinformation suggests some Americans may be avoiding having an experience of cognitive dissonance." - 'Poll shows errors in beliefs on Iraq, 9/11' The Charlotte Observer, 20th June 2003 |
#169
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The Revolution Will Not Be Televised wrote:
On Tue, 05 Aug 2003 02:24:43 GMT, Guy Alcala wrote: The last week has given me time to order and read Middlebrook's "The Battle of Hamburg" and "The Berlin Raids," both full of good info re loads. Here's some typical bomb and fuel loads he gives for the first raid on Hamburg, from the former book: Good books, and it's worth getting the other two in the series (Peenemunde and Nuremburg Raids), but there is the odd good-faith discrepancy, due I suspect to Squadron ORBs and aircrew logs varying for some reason from Group returns to BC HQ and the subsequent BC raid reports. I've read the Nuremberg and maybe the Peenemunde ones, and have the Schweinfurt-Regensburg one on order just for comparison. I've been a Middlebrook fan ever since I first read "First Day on the Somme" umpteen years ago. difference in MTOW. "The Berlin Raids" contains a statement by a pilot mentioning that the (Merlin, IIRR) Lancs had their MTOWs increased from 63 to 65,000 lb. during that period (i.e. post-Hamburg). I'll need to find it again. I remember that: I think this was 1 Group again. Found it and you're right, it was a 1 Gp. CO. specifically, Wg. Cdr. G.A. Carey-Foster, 101 Sq. at Ludford Magna (don't remember if A.B.C. was in service yet). Middlebrook quotes from Carey-Foster's diary, apparently on or around 18/19 November 1943: "All-up weight has been increased to 65,000 pounds for the first time"; Middlebrook comments that 'this would allow each Lancaster to carry up to half a ton more bombs. But the move was not as effective as might appear. It was soon apparent that more crews were jettisoning part of their bomb loads in the North Sea to retain some maneuverability if attacked by a night fighter before reaching the target.' The diary quote is more ambiguous than I thought. To me it's at least implied that this was an administrative rather than structural increase, but from the quote I can't say that's definitely the case. Oh, with reference to Pete's and my attempt to redesign the Lanc (and Bomber Command) for day use a few years back at the order of Air Chief Marshal "Butch" Kramer, and how long the process was likely to take starting from the fall of 1943 ("Butch" was loathe to accept our estimate of 6 months minimum to convert enough a/c to high-altitude engines to supply a single squadron, with a year more likely for an entire group with all the other mods needed), serendipitously Middlebrook includes the following (pg. 96): I don't think two-stage merlin production was sufficient until well intop 1944 for seriously considering two-stage engines for production Lancasters en mass. They were too badly needed for Mustangs, Spitfires and Mosquitos first. That was part of our reasoning, along with engine mount and airframe compatibility design issues and modifying the a/c production lines. Actually, ACM Kramer really wanted us to use radials, but we pointed out that the only way to get a significant high altitude daylight force into service within a year using _British-designed_ heavies was to use two-stage Merlins, because there was no high-altitude version of the Hercules in production. We were trying to find out more info on the turbocharged Hercules models that had been used for the pressurized Wellingtons, but lacking any detailed info on that engine we assumed that considerably more engine development as well as production tooling would be required to get those into mass production and service. Personally, I've since come to the conclusion that the simplest approach would have been for the proposed (in Art's alternate universe) day RAF heavy bomber force to use B-24s. This would require some re-scheduling of U.S. Bomb Group training and deployment, but would eliminate the need to cut down the training times (first one month, then another) for U.S. replacement crews that took place in the late fall of '43 owing to the high loss rates. We'd figured 3 Gp. was the best Group to convert first. 3 Gp. would have been the best to start with because of their location in the same general area as 8th BC, and because the Stirling was the least useful night bomber. Taking them off ops to retrain and convert, whether replaced with B-24s, Lancs or Halifax IIIs, would cause the least negative effect to the night force. "But the [PRO] contains an interesting correspondence concerning a request made by Bomber Command for six special Lancasters, one for each of the Pathfinder heavy squadrons, to be used by future Master Bombers. Yes, and I believe these became Lanc VIs subsequently. They weren't used particularly heavily, so far as I can see, and there was no effort to replace them over time, although they would seem like a good idea. Right, it appears there were only 10 or so. I suspect PFF abandoning the Master Bomber technique on big area raids (see Middlebrook's comments on the early Berlin raids which had allocated Master Bombers) immediately after they appeared had something to do with this. Slightly before they appeared, actually, only bringing it back later. Then 5 Gp. started to use Mossies at low level for this role, exactly opposite to 8 Group's ideas. an initial delivery date of the first aircraft to Rolls-Royce at Hucknall for final modification before handing over to the Pathfinders was given as 15 November -- again just in time for the late November non-moon bombing period -- with the other five aircraft arriving at regular intervals up to the end of February. In fact, the first aircraft did not arrive at Hucknall until 5 December, and then required a further six weeks of work before it was delivered to the Pathfinders, eventually arriving in time for the last raid of the Battle of Berlin [Guy Note: 24/25 March 1944]." This would tie in with Saward's hi-jacking of six H2S Mk III sets from Coastal Command, although I think the Lanc VIs arrived too late to be considered for fitting the radar too, and they ended up in Lanc IIIs instead. Right, the H2S Mk. IIIs went into regular PFF a/c. Interestingly enough, "The Berlin Raids" states that the Halifax IIIs (after the II/Vs had all been removed from Berlin missions) still had a higher loss rate than the Lancs. I'm looking for the exact quote, but I think this was true regardless of Lanc type. It may well be true, but overall loss rates for the war for the B.III were significantly less than the B.II and V versions and even better than the Lancs according to Bingham's book on the Halifax. They'd certainly be better than the Halifax II/Vs. Of course, the level of resistance would affect this, but the IIIs were active in the end of 43 and throughout 44 when casualties were high enough to give them a valid comparison to the Lancs on the same raids. Unfortunately, books on the Halifax are almost non-existent in this country (not that Lanc books are very thick on the ground), so I'm having to work through peripheral sources like Middlebrook. I'll have to re-read it, but I'm pretty sure Middlebrook shows the IIIs had a worse loss rate in "The Berlin Raids" period than the Lancs, when both were on the same mission. Many of the raids to Berlin only used Lancs, so that skews the Lanc losses. After the invasion it probably made little difference what you were flying, as the loss rate had dropped so low (and many of the missions were flown by day). And you did have a better chance of bailing out of a Halifax in an emergency. Guy |
#170
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The Revolution Will Not Be Televised wrote:
On Tue, 5 Aug 2003 00:28:15 -0400, (Peter Stickney) wrote: snip As you can see, at cruise, they're about even. While I wouldn't be surprised it the Lanc II was a bit more draggy, and possibly heavier, (Each Hercules weighed 500# more dry than the 20 series Merlin, but that doesn't include the Merlin's radiators and coolant.) I've seen comparisons that give about 250lbs extra per engine to the Hercules version in early 1943, presumably when compared to the fully-equipped Merlin versions, but this comes from a secondary source (Holmes) and without context, and so it doesn't address the comparison over time properly as the I/III auw was raised. FWIW, Tubbs says that each of the Lanc Merlins had between 11 and 12.5 gallons, presumably Imperial, of 70/30 water/glycol coolant. I have no idea what glycol weighs, so assuming straight water you're talking ca. 100-125 pounds per engine of coolant. Guy |
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