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#21
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The Revolution Will Not Be Televised wrote:
On Thu, 04 Sep 2003 19:37:14 GMT, Guy Alcala wrote: snip Even moving the tips out for greater wing area is going to leave it struggling with poor engine output at altitude and serious airframe weight issues. The engine output should be no worse than the Halifax III, but I grant you the weight issues. OTOH, the Stirling seems like it was quite strong, so a boost in MTOW may have been possible. Actually, reducing the weight might have helped more to raise the ceiling, and you won't be getting many Hercules XVI engines until 1944 as the Halifax production will eat them up. You might as well stick to using them pretty much as is as an interim type, and get another ten squadrons to increase the short-penetration supporting missions along with the six-eight squadrons of 2 Group. They can then re-quip with the B-24 over time, after gaining daylight experience during the supporting ops. Assuming we can get the B-24s. Otherwise it's likely to be Halifax IIIs, in which case we might want to take another look at those extended-tip Stirlings again. snip [B25 bombload] Personally, I wonder if your source that claimed 2 x 1,000 'and' 4 x 500 should have read 'or', as that would fit better with the claimed bomb bay capacity in several sources. It wouldn't be the first time that has happened. Agreed, and I will check the Squadron ORBs when I get the chance. Any American stats to compare with this? Not yet, but I've got a bunch of B-25/B-26 books on order from various libraries, so hopefully they will have something useful. I've also been reading Alfred Price's "Spitfi A Complete Fighting History," which has some interesting info on Mk. V fuel burn, range, Spit drag, etc. I'll cull that and try to post the more interesting stuff for your and Pete's benefit. Guy |
#22
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On Sat, 06 Sep 2003 19:07:13 GMT, Guy Alcala
wrote: Not yet, but I've got a bunch of B-25/B-26 books on order from various libraries, so hopefully they will have something useful. I've also been reading Alfred Price's "Spitfi A Complete Fighting History," which has some interesting info on Mk. V fuel burn, range, Spit drag, etc. The most useful I found were the Merlin 45/46 consumption figures with relevant TAS figures with associated rpm and boost. I can also vouch for their accuracy, having read the original report in the PRO (which was filed with some Fighter Command stuff from the Dieppe period IIRC). The original Spitfire AFDU, A&AEE and RAE reports in AIR 16 were getting a little scrappy though: that particular bulging folder has clearly been out to a few researchers before I got my paws on it. Gavin Bailey -- Another user rings. "I need more space" he says. "Well, why not move to Texas?", I ask. - The ******* Operator From Hell |
#23
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The Revolution Will Not Be Televised wrote:
On Sat, 06 Sep 2003 19:07:13 GMT, Guy Alcala wrote: Not yet, but I've got a bunch of B-25/B-26 books on order from various libraries, so hopefully they will have something useful. I've also been reading Alfred Price's "Spitfi A Complete Fighting History," which has some interesting info on Mk. V fuel burn, range, Spit drag, etc. The most useful I found were the Merlin 45/46 consumption figures with relevant TAS figures with associated rpm and boost. That was one I was thinking of, but if you've seen it that will save me some typing. I think Pete will find the drag numbers more interesting, but maybe he'd want to see the Mk. V fuel burn numbers as well. If he does and you've got a scanner (I don't), could you send them to him? I can also vouch for their accuracy, having read the original report in the PRO (which was filed with some Fighter Command stuff from the Dieppe period IIRC). The original Spitfire AFDU, A&AEE and RAE reports in AIR 16 were getting a little scrappy though: that particular bulging folder has clearly been out to a few researchers before I got my paws on it. Hopefully someone will scan _all_ this stuff before it gets destroyed. We've got bits and pieces here and there on the web and elsewhere. Guy |
#25
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In article ,
Guy Alcala writes: The Revolution Will Not Be Televised wrote: Personally, I wonder if your source that claimed 2 x 1,000 'and' 4 x 500 should have read 'or', as that would fit better with the claimed bomb bay capacity in several sources. It wouldn't be the first time that has happened. Agreed, and I will check the Squadron ORBs when I get the chance. Any American stats to compare with this? Not yet, but I've got a bunch of B-25/B-26 books on order from various libraries, so hopefully they will have something useful. I've also been reading Alfred Price's "Spitfi A Complete Fighting History," which has some interesting info on Mk. V fuel burn, range, Spit drag, etc. I'll cull that and try to post the more interesting stuff for your and Pete's benefit. Here are the B-25's bomb station options, as called out in teh U.S. Navy Standard Aircraft CHaracteristics for the PBJ (Which was a B-25 with a different paint job) Internal: 1 x 2,000# or 2 x 1600# 3 x 1000# GP 4 x 1000# AP (The AP bombs are much slimmer 3 x 650# 6 x 500# 8 x 250# 24 x 100# With the 215 (U.S Gal Bomb Bay Tank: 2 x 1000# 2 x 1600# 2 x 650# 4 x 500# 4 x 325# Depth Charge 12 x 100# Externally, (Bay doors open) there was provision for a Mk 13 torpedo. As for the Stirling, well, actually, fir all its bulk, it doesn't seem that heavy.They really should have taken the fuselage out of hte box before they bolted the wings on, though. -- Pete Stickney A strong conviction that something must be done is the parent of many bad measures. -- Daniel Webster |
#26
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Peter Stickney wrote:
In article , Guy Alcala writes: The Revolution Will Not Be Televised wrote: Personally, I wonder if your source that claimed 2 x 1,000 'and' 4 x 500 should have read 'or', as that would fit better with the claimed bomb bay capacity in several sources. It wouldn't be the first time that has happened. Agreed, and I will check the Squadron ORBs when I get the chance. Any American stats to compare with this? snip Here are the B-25's bomb station options, as called out in teh U.S. Navy Standard Aircraft CHaracteristics for the PBJ (Which was a B-25 with a different paint job) Internal: 1 x 2,000# or 2 x 1600# 3 x 1000# GP 4 x 1000# AP (The AP bombs are much slimmer 3 x 650# 6 x 500# 8 x 250# 24 x 100# With the 215 (U.S Gal Bomb Bay Tank: 2 x 1000# 2 x 1600# 2 x 650# 4 x 500# 4 x 325# Depth Charge 12 x 100# Externally, (Bay doors open) there was provision for a Mk 13 torpedo. Yeah, I've got that too. The question is whether there is room (and shackles) for the _combination_ of 2 x 1,000 and 4 x 500 lb. bombs, which is why I'd like to see a bomb station arrangement diagram. The credited 4,000 lb. load appears to only be possible carrying 4 x 1,000 lb. AP bombs. Several sources state that the 2,000 lb. station had to be removed to allow 3 x 1,000 lb. GP to be carried, and that the 2,000 lb. station was deleted from the production a/c at some point in 1944 or so. With the 2,000 lb. station in place, only 2 x 1,000 lb. bombs could be carried (this assumes these sources are accurate). The British a/c in 2 Gp. were early Cs and Ds IIRC, and they didn't start getting Js until late in 1944. This source also doesn't list the external station capacities, which were definitely available. As for the Stirling, well, actually, fir all its bulk, it doesn't seem that heavy.They really should have taken the fuselage out of hte box before they bolted the wings on, though. The empty weight (46,000 lb. IIRR) has always seemed far higher than was the case with the Lanc or Halifax, and the MTOW (70klb. IIRR) not that much more. It is possible that this is a mistake and isactually the OWE rather than the empty weight losted for the others. Still, its range with a comparable bombload is significantly less than either, and while the wing design undoubtedly plays some part I expect the main factor is the restricted useful load. Shorts' structural methods seem to stem from the flying boats, and appear a bit out of date. Come to think of it, ISTR a Roy Braybrook article in AI some years back, where he showed that their flying boats had rather poor useful loads compared to comparable American models, for much the same reason. Guy |
#27
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Peter Stickney wrote:
In article , (The Revolution Will Not Be Televised) writes: On 2 Sep 2003 21:17:46 -0700, (Guy alcala) wrote: snip Vader states that the Mk VIIIs had the 'C' wing, which implies that the Mk. IXs should have been able to be given LE tanks with little difficulty. I'm under the impression that the substantive changes to the Mk. VII/VIII were in the fuselage, and except for the tanks the wings were identical. Does anyone actually KNOW what the structural/internal changes were from the Mk.V/IX etc. to the Mk. VII/VIII? We all know about the tail wheel, but there had to be more than that. I don't know, but the internal wing spars, which I suspected would show a difference, appear to be identical between the Vc and the VII, in which case there should be no problem with deleting the outboard MG positions in favour of more fuel tank capacity in the Vc-airframed IX. The shorter-span ailerons appear to be shortened at the wing-tip end. If there were any fuselage differences, they didn't stop the late-production IXs getting rear-fuselage tanks anyway. I'm back. I've been examining cutaways & measuring & doing sums like a numerate Dervish, and, while I can't give a definitive answer, I can make the following observations: The Mk Vc wing would certainly be suitable for teh leading edge tanks. I'd go so far as to say that if you were really concerned about volume in that area, ditching on or both of the .303 guns in each wing would open up a bunch of space, withoug compromising much in the way of firepower. I don't think that's necessary, as the exploded view of a Mk. XIV in Price's "Spitfi A Documentary History" shows the L.E. tanks are inboard of the cannon. If tanks could also be installed outboard in place of the MGs, then I'd probably go for it and accept the somewhat greater vulnerability in combat, but just getting standard Mk.VIII tankage (123 Imp. Gal. total) would be fine for a start. The big deal with the Mk V, and volume behind the cockpit, is that hteat's where the radios live. Going with a smaller/lighter set would allow something like teh Mk IX's 29 Imperial Gallon tank. Not sure what you mean here, as the Mk. VCs were given a 29 Imp. Gal. ferry tank for the Gib-Malta ferry flights. The later Mk. IX/XVI had 66 Imp. gal. rear tanks. Note that on the Mk IX, the only way to keep the CG acceptable with the aft tank was to use it only in conjunction with one of the belly tanks. H'mm, at least with the Mk. XIV, the Cg moves aft when drop tanks are carried, not forward. See http://www.fourthfightergroup.com/ea...41weights.html I don't really view that as a big deal for an escort fighter, unless you expect to be engaged immediately at the French Coast. The recommended tank sequence would be, after takeoff, to use the aft fuselage tank, then the external tank. (I keep wanting to call that marsupial-looking excrescence the "carbuncle", for some reason) The 29 Imp Gal tank should last somewhere between 15 minutes to 1/2 hour, depending on power settings, so that gets you through form-up, climbout, and pretty much across the Channel. Part of the pilot's notes for the F./F.R. XIV are online, and the FR. XIV flight restrictions contains the following statement: "On F.R. Mk. XIV a/c it is essential, for reasons of stability, that the rear fuselage tank should be emptied before flying at altitudes in excess of 15,000 feet." It also states that the fuel tank sequence for the F.R.14 is t/o on main tanks, switch to rear fuselage tank and empty it, then feed from drop tank. See http://www.geocities.com/spades53.ge...4_notes_13.jpg ISTR that this tank is ca. 33 gallons. Guy |
#28
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Peter Stickney wrote:
I'm back. I've been examining cutaways & measuring & doing sums like a numerate Dervish, and, while I can't give a definitive answer, I can make the following observations: snip Spit comments BTW, I know we've been sidetracking you with work on the Spit, but were you able to run any numbers for the Lanc B.2? Guy |
#29
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On Mon, 08 Sep 2003 05:47:33 GMT, Guy Alcala
wrote: [welcome back Peter, with your smoking slide-rule] The big deal with the Mk V, and volume behind the cockpit, is that hteat's where the radios live. Going with a smaller/lighter set would allow something like teh Mk IX's 29 Imperial Gallon tank. Not sure what you mean here, as the Mk. VCs were given a 29 Imp. Gal. ferry tank for the Gib-Malta ferry flights. The later Mk. IX/XVI had 66 Imp. gal. rear tanks. The standard fuselage Mk IX/XVI got a 75 Imperial gallon rear fuselage tank, with tear-drop canopy versions with the cut-down fuselage getting 66 gallons. My thinking was for the 29 gallon Gibraltar ferry rear tank, or something pressurised/self-sealing with a similar capacity in the LR Vc, with additional wing tankage for the LR Vc or LR VIII & IX coming from the outboard MG position's, e.g. using the E-wing armament or even 2 x Hispanos with 2 x .303 MG's in the inboard cannon position available in the C wing, while stuffing a further 10 gallons or so of fuel in the outboard MG positions, as Pete has pointed out. This would be additional to the Mk VII/VIII wing tanks with their (conservative) 25 gallon capacity which were positioned further inboard of the first cannon mounting. Total here would be for something like 35 gallons in the wings additional to the 85 gallon conventional tankage, 29 gallon rear fuselage tankage and external drop tanks of up to 90 gallons capacity. Gavin Bailey -- Another user rings. "I need more space" he says. "Well, why not move to Texas?", I ask. - The ******* Operator From Hell |
#30
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The Revolution Will Not Be Televised wrote:
On Mon, 08 Sep 2003 05:47:33 GMT, Guy Alcala wrote: [welcome back Peter, with your smoking slide-rule] The big deal with the Mk V, and volume behind the cockpit, is that hteat's where the radios live. Going with a smaller/lighter set would allow something like teh Mk IX's 29 Imperial Gallon tank. Not sure what you mean here, as the Mk. VCs were given a 29 Imp. Gal. ferry tank for the Gib-Malta ferry flights. The later Mk. IX/XVI had 66 Imp. gal. rear tanks. The standard fuselage Mk IX/XVI got a 75 Imperial gallon rear fuselage tank, with tear-drop canopy versions with the cut-down fuselage getting 66 gallons. Right. My thinking was for the 29 gallon Gibraltar ferry rear tank, or something pressurised/self-sealing with a similar capacity in the LR Vc, with additional wing tankage for the LR Vc or LR VIII & IX coming from the outboard MG position's, e.g. using the E-wing armament Probably not an option, as we'd need the limited number of .50 cals for flexible nose guns in the Halifax IIIs, if the B-24 deal doesn't come off. or even 2 x Hispanos with 2 x .303 MG's in the inboard cannon position available in the C wing, while stuffing a further 10 gallons or so of fuel in the outboard MG positions, as Pete has pointed out. This would be additional to the Mk VII/VIII wing tanks with their (conservative) 25 gallon capacity which were positioned further inboard of the first cannon mounting. Total here would be for something like 35 gallons in the wings additional to the 85 gallon conventional tankage, 29 gallon rear fuselage tankage and external drop tanks of up to 90 gallons capacity. Seems like it would be a lot easier to boost the forward fuselage capacity of the Mk. V/IX up to 96 gallons by swapping in bigger tanks (we know there's room there), before you add all those other tanks and the associated plumbing. I agree you'd still want the L.E tanks, but let's do the easiest stuff first. The extra 11 gallons in the enlarged forward tanks buys perhaps 10 minutes of cruise coming home: let's be _real_ conservative and call it 30 miles. Then we'll also need to enlarge the oil tank at some point. The outboard tanks you describe are so small that I wonder if they're worth the weight of all the plumbing, plus the extra vulnerability (remember that these tanks feed into the main tanks after room has been made in the latter, so they won't be used in combat - no one's going to transfer fuel while they're fighting). Guy |
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