If this is your first visit, be sure to check out the FAQ by clicking the link above. You may have to register before you can post: click the register link above to proceed. To start viewing messages, select the forum that you want to visit from the selection below. |
|
|
Thread Tools | Display Modes |
#1
|
|||
|
|||
Long-range Spitfires and daylight Bomber Command raids (was: #1 Jet of World War II)
On Mon, 18 Aug 2003 20:39:22 GMT, Guy Alcala
wrote: Let's just say my reply has been delayed, but here goes. [snip more gratuitous and unprovoked logical discourse. NB all gallons referred to in this post are Imperial, not the inferior Yanqui oppressor's titchy competitive effort.] [Quill on longitudinal instability on Mk Vs] Ah, now we can compare close readings and interpretations of same. Onward. We agree on all the above, but I posit that the commitment would result in a shift to Mk. VIIIs (or Mk. IXs with similar tankage), accepting the likely temporary decrease in production. Actually I don't see there being a production shortfall, except at Castle Bromwich which would need some retooling to produce Mk VIII airframes instead of IXs as it ended Vc production in July - October 1943. The rear fuselage tanks could be post-production fittings at Maintenance Units, which would only receive as many airframes for fitting as tanks were available. So there'd be two deployment streams (short-range and long-range Mk VIIIs) until Boulton Paul or whoever else could produce sufficient tanks for full production fitting. Much like the behaviour of the actual Mk IX/XVIs with rear-fuselage tanks in 1945. True, but those Mk.IX/XVIs also had extra fuel in the regular fuselage tanks (ca. 94-96 gallons, depending on the source) forward of the datum. 66 or 75 gallons according to the Pilot's Notes and Shacklady & Morgan. And correct me if I'm wrong, but ISTR that only those a/c with cut-down rear fuselages got the aft tanks; Nope: the standard fuselage versions actually got larger internal rear fuselage tankage - 75 vs 66 gallons. At least that's what the Pilot's Notes say. [BTW, the VII/VIII/PR.X Pilot's Notes have some range/climb/cruise graphs which I think might be relevant to this discussion] and if you want to extend the escort range it's the amount of fuel you can carry internally to fight and return on that determines escort radius, no matter how much fuel you hang externally to boost endurance. Agreed. This is why the rear-fuselage tankage issue is critical to this speculation. Not for combat radius/return, unless you can use rear fuselage tankage for that; otherwise you're just extending the endurance and ferry range. This is how Supermarine and the RAF saw it: instability in the early stages of a flight was acceptable, providing that the fuel load had been consumed to the point of stability before the aircraft entered combat. As this is the attitude historically adopted with rear-fuselage tanks in the Mk IX/XVI, it's not such a stretch to invoke it a little earlier. The Mustang could only retain a fraction (ca. 25-50%) of that rear tank fuel to use for combat without being dangerously unstable, with the contemporary Spit possibly (probably?) being unable to retain any of it; Actually, the relevant testing in January 1945 revealed that the acceptable manoevering limit with the 75-gallon rear fuselage tank was 9.9 inches aft of the datum, or after 34 gallons had been used. Clearly the tank didn't need to be emptied for this to be achieved. at best, it could retain the same fraction as the Mustang. The Mustang with rear tank didn't have 269 U.S. gallons to fight and return on; it had somewhere between 205 and 227, depending on what fraction of the aft tank capacity allowed acceptable combat handling. In this case we have a Mk IX with 85 gallons internal forward tanks and about 40 gallons in the rear tank within apparently tolerable limits for combat. To be an acceptable long-range escort, the Spit still needed the extra forward fuselage fuel of the later Mk. IXs and the Mk. VIIIs, plus the leading edge tanks of the latter. The Mk. VIII carried 124 Imperial gallons internally (149 U.S), ALL of which was usable in combat, plus whatever extra fuel usable in combat (if any) a rear tank provided. Ah, here we disagree: as far as I know, most IX/XVIs didn't have enlarged forward tanks (in the traditional position forward of the cabin bulkhead, behind the engine), and most MK VIIIs seem to have been similar. So the best reliable figure for the internal capacity of the Mk VIII would actually be around 110 Imp galls. I suppose Air Commodore Alcala, Director of Fighter Operations in this scenario, will be pressing the Air Member for Research and Development to get them all with the enlarged forward tanks as well.... [increased tankage of 2 Spits IXs from Wright Field, July 1944] In the case of the Spit wing it seems to have been a strength issue, at least according to Quill Yes, but I suggest what Wright Field did was a reliable indicator of what the USAAF would have done if Spitfire production and procurement was within their grasp. A&AEE whinges about instability would get short shrift in this situation. . So I suggest basic experience of rear-fuselage tankage, and measures to combat the worst CoG issues resulting were at hand in plenty of time to have an impact on the postulated fitting of rear-fuselage tanks in the summer of 1943. The difference being that the flights to Gibraltar were ferry flights, and no formation maneuvering or combat flying with the aft tanks full was required. Sure, but how different is this from Vcs emptying them on the climb out of East Anglia and the cruise out to Holland? The short-ranged Spit Vs and IXs could handle combat in those areas, while the LR Spits would be briefed to pick up their escorts further out over the Zuider Zee. Giving them an extra 30-45 minutes of flight on internal fuel, even with the most restricted utility (e.g. only on the way in, no combat endurance to remain after entering combat) is still of use, and reflects the utility of giving them drop-tanks to start with. The final determinant is the distance over enemy territory a Vc could return on forward tanks alone after exhausting the rear tank, dropping the 90-gallon drop-tank and spending 10 minutes at high throttle settings in combat. This is obviously *not* a profile which makes it contender for deep-penetration escort, but it still means they should be able to operate out across Holland beyond Amsterdam and up to the German border. Even a marginal improvement like this would have had a real and clearly-observable benefit in supressing bomber losses. In the end, even the RAF cleared the rear-fuselage tanks for production usage in 1945, and they were happy enough to fit half of the tankage in the FR XIV and the full thing in the XVIII. Again, both a/c with cut-down rear fuselages. Yes, but the cut-down fuselage doesn't seem to be a factor in deciding whether a Spit got rear-fuselage tanks or not: the IX and XVI with conventional fuselage got them, the FR XIV got them and I suspect the XIV would have got them if it hadn't been succeeded on the production lines by the XVIII in 1945, which only came in a cut-down fuselage version. As it was, the example of the FR XIV and the IX/XVI indicates the cut-down fuselage actually had a lower capacity for rear-fuselage tankage (66 vs 75 gallons). Getting to our respective readings and conclusions on Quill, I note that he says in the case of the Mk. 21 that he disagreed with A&AEE on whether the Mk. 21's handling was acceptable at a certain point, and that he felt that such handling deficiencies could be accepted to get an a/c with superior performance into the field (he's also man enough to admit that he may have been overconfident by this point that average squadron pilots wouldn't have had serious difficulties, based on his own skills). I suspect A&AEE were right on that point; but it's instructive to see, yet again, that Quill states a fix for the stability and trimming issues that plagued the F.21 in 1944 was known about (enlarged tail surfaces), but production issues ruled it out until 1945. Take the MAP monkey off Supermarine's back, demanding production at the expense of development all the time, and this and a lot of other relevant problems could have been dealt with earlier. Now, it may just be a question of him not thinking to mention it, or the way he worded it, but he maentions no such disagreement between himself and A&AEE regarding the handling of the rear fuselage tank-equipped a/c; he just says that the handling wasn't acceptable for a long time, and required a lot of development. The origin of the "acceptability" comments over the rear-tank tests appears to be Supermarine's development testing. Aircraft would only go to A&AEE after they had arrived at what they saw as a production standard (e.g. Quill testing the 75 gall RF tank in July 1944, but Boscombe Down not getting it for another six months). Also, note that the A&AEE testing was not a peacetime acceptance test as such - the aircraft and fittings involved were often ordered into production anyway to minimise delays to production totals, and A&AEE testing was often being performed as representative of current or imminent production. F.21's were actually being produced before and after A&AEE first critically reported on them. I'm certainly not going to claim, based on such flimsy evidence, that this is definitive proof that the a/c couldn't have been flown in operations with an aft tank with accceptable handling much earlier given sufficient motivation, especially given your comments re the prevailing attitude of the A&AEE. But I do think it at least suggests that the Cg problems were real and agreed to be so by both the A&AEE _and_ Quill. And that's as far as I'm prepared to gaze into my crystal ball. Your reading may well be different. And it is, I'm afraid. A&AEE seem to get their first rear-tank Spit in January 1945, and quantify it as acceptable once 34 gallons out of the 75 were used. Nobody was going to Boscombe Down and pushing this idea, the whole issue seems to come from Supermarine. Posit a burning interest in the Air Ministry in increasing inernal tankage in 1943 (e.g. ACM Kramer getting upset) and I suspect things would have been remarkably different. I suggest with the equivalent of Eaker, Spaatz and Arnold lighting fires under people's arses to increase range in 1943, this would have happened earlier. Not Eaker or Spaatz; it was Arnold through Giles. From "To Command the Sky": I stand corrected. As to someone lighting fires for the R.A.F., that was what Pete and I were postulating, only for the Spit IX/VIII, with the highest priority to getting increased range British fighters in the U.K. soonest, with all other Spit improvements pushed back. Grabbing available Mk. VIIIs first (the MTO and CBI/PTO will just have to suck it up for a while), at the cost of MK.XII/XIV production, It wouldn't have been at the expense of Mk XII or XIV production if you're specifying a start after Schweinfurt II in October 1943. The XII production run had finished, the XIV was settled month beforehand and was going to start to appear in a dribble in December 1943 as production deliveries of Griffon 65s began. then either expanding Mk. VIII production at the cost of the Mk. IX That would have been possible, but only at the point of converting Castle Bromwich over to the VIII in the summer or autumn of 1943. This needs a demonstration of the effectiveness and need for it somewhat earlier: hence my LR Vs in 12 Group in July. or (if possible) transitioning to Mk. IXs with the extra leading edge tanks of the VIII, with aft fuselage tanks and whatever airframe mods required to pack usable _combat_ fuel in. That would have required prducing the VIII wings & airframe, I believe, rather than stuffing a Merlin 60-series into a Vc airframe as was done to churn out IXs. So I think there would be production infrastructure issues. As it was, the Supermarine production group around Eastleigh delivered about 90 Mk VIIIs to the RAF in July 1943, which should be enough to prove the concept if you grab them all. Sure, and that with an aft tank was next on the agenda after boosting production of the standard Mk. VIII/leading-edge tank Mk. IX. Either of the latter should have given us an escort radius of 250-300 miles. See my note on the actual forward-tank capacity of most VIIIs. Although this may have been changeable. Unfortunately, a similar chart for a Mk. V doesn't seem to be available on the site, but I have my doubts that the Mk. V was carrying around any such ballast in 1943, or if it did, so far aft. Of course, AB197 was a very early Spit IX (the report date seems to be June 10th, 1942), so that ballast was probably reduced as more operational equipment was added, but it at least suggests (combined with the Mk. V's further aft Cg vs.the Mk. IX as reported in various tests on the site) that the Mk. V was pretty much at the limit, while the Mk. IX had considerably more Cg range available. I can't find anything to substantiate this with the V myself, and I understand the validity of your reservations. Nevertheless, the critical issue as I see it is whether any rear tankage could become available given improvements in the CoG by means of the enlarged elevator horn balance and convex Westland elevator. I fully accept this would, in all probability, have been insufficient to allow a 75 gallon rear-fuselage tank to be carried and cleared for combat. The critical issue is whether this would have been enough to permit a rear-fuselage tank to be used in the early stages of flight to extend the pre-combat range. Given that this was done with a 29 gallon rear tank, I think there is a useable margin, albeit a smaller one than a LR-fitted Mk VIII with better weight distrubution and enlarged tail surfaces would have. I'm focusing on using the V not because it had more or even comparitive utility with the Alacal/Stickney LR Mk VIII (something I've argued for in the past myself), but because even with the greater constraints involved, it was a more likely concept-demonstrator in the historical timescale. If you want an overnight conversion to LR Spit IXs at any given point without the example of a LR operational trial in the RAF to start with, you'd have to posit the removal of most of the higher command and their staff involved to eliminate their existing preconceptions and prejudices. So this is why I think LR Vs would be an issue worth consideration even taking into account their inferiority from all aspects of the job when compared to the VIII. I think it's more credible to posit changes in the Vs proving the concept, as this would be more institutionally tolerable. This is important from my point of view, as I think any counter-factual speculation has to be made within the known constraints of the industrial, economic and institutional context to remain credible. [production pressures] I don't underestimate the pressures, I just think (as you mentioned a few paragraphs above) that if the decision had been made to go over to daylight, fighter range extension would have increased in priority and changes would have to have been accepted, whatever the disruption elsewhere. Because otherwise, it wasn't going to work. Indeed, but when the RAF actually faced this dilemma, at the end of 1939 and then again in spring 1941, they abandoned daylight bombing. The two concepts had become divorced, for understandable external reasons, and asserting a sudden and complete reversal of this is stretching the credibiluity of the institutional appreciation involved in the speculation. Now I think the concept is possible, and a valid piece of historical speculation, but I also think it has to work within the context involved, and, frankly, anybody demanding a reduction in Spitfire production in favour of speculative operational development was on a losing wicket. The British strategical position in this respect can't be overstressed too much: the USAAF had a doctine and institutional ambition towards independence which was served by the 8th AF campaign, secured by other forces doing things like protecting their bases and dealing with the existing war against Germany. They had room to stop and rethink tactics and strategy, and change production priorities accordingly. The British did not have this space. They had to maintain existing commitments and fight the war as it existed from a smaller industrial and economic base closer to the enemy threat. Proving strategic concepts, even ones which had great war-winning potential, was a luxury that could not come at the expense of the means for repelling the enemy in the meantime. The RAF could not prejudice production of their main fighter when it was needed for home defence, operations in the MTO and Far East and supply to the Russians. The difference between these commitments and facilitating daylight strategic bombing was the difference between fighting the war and demonstrating an abstract concept. Whatever happened in the skies over Germany, Fighter Command were conceiveably in a position to lose a war for national survival. The 8th AF wasn't. No lack of respect intended. The 8th might prove vital in winning the war, but high Spitfire production was known to be needed meanwhile to avoid defeat and stay in the war, which was an essential prerequisite. The Mk XIV was settled long before production started in October 1943, the number of airframe's you'd be losing in that year (six for development work most of which didn't need massive work for Mk XIV testing and ended up testing contra-props instead, maybe 20 for delivery to operational squadrons) is trivial. Simply cutting out the Mk VIII airframe allocation to the Mk XII production might free twice as many as that. And we'll be happy to take them, and we'll just have to accept the occasional FW-190 Jabo getting through. They weren't much of a threat on the larger scale, but if you're assuming a change of events in autumn 1943, the XII production run is effectively already over and done with. But we'll also take the airframes that became 610 Squadron's Mk. XIVs in January 1944. If you've got CBAF producing VIIIs or LR IXs in January 1944, which is perfectly possible if you start in July or August 1943, there's no shortage of airframes. Also, bear in mind production factor I've pointed out earlier - it's likely you'll have more airframes than rear tanks available by the end of 1943, so you might as well do something to enhance the remaining non-rear-tanked airframes. I really don't see either Griffon Spit (XII and XIV) having a substantive impact on LR Spit VIII supply in late '43 - early '44. I do think that the F.21 and later Seafires would have been delayed if Supermarine were working like demons on rear-tank stability problems in autumn 1943, though. But as I've already said, small loss. If we're talking about an operational need in the summer of 1943, No, the postulated date of the decision (to go over to days) was sometime in the fall of '43, although the exact date was a bit unclear. It seemed to be in the September/October timeframe, but we were unable to get ACM Kramer to be more precise. Well, pending a decision from "Butch" Kramer, let's assume either the first or second Schweinfurts as the PoD for this speculation. The faster the better, as far as the Controller of Research and Development and the MAP production executive are concerned: getting Castle Bromwich to produce Mk VIII wings and getting Boulton Paul to do the pressurised, self-sealing tanks are the major bottlenecks in the short term. Good points, and I don't disagree about the utility of the Mk. V as 'certainly better than nothing,' and better to lose people one at a time rather 7 or 8 at a time Again, my main concern with the V is whether they could in fact have been given the radius (not range). I appreciate the distinction, but I think increasing range was the first, and most easily achieveable step. I don't think the early XVIs actually had the rear-fuselage tankage when they first came off the production lines (September 1944), Right, I should have said the rear fuselage tank (and I think they only came in with the cut-down rear fuselage) about 16-18 months early, as i forget just when those versions came out, but I think it was only in '45. That's right. But while I'm always sceptical about blanket counter-factual claims about the relative ease of any one measure changing things, I have to say I can't see any overpowering practical reasons why they couldn't have arrived sooner, once the institutional prejudices and conflicting strategic alignments have been addressed. And I honestly think they are addressable. Please desist from this moderate rationality or I will complain to your ISP. Did I mention that I have INCONTROVERTIBLE PROOF that the U.K. government has been testing UFOs ( and dissecting ALIEN CORPSES) at their base at Machrihanish, Nah, you're just confusing Alien corpses with the average westie. Understandable mistake. We only retain them to give the midges a round-the-year locally-available food supply until the German tourists appear in the summer. cleverly disguising test flights of same as those by Aurora and, in times past, SR-71s? Wait, I hear the black helicopters coming to get me. I can feel the beams as they try to alter my brain. Excuse me while I done my tinfoil hat. Interesting theory, although it lacks credibility, until we acknowledge the critical role played by the Templars and the Illuminatii in the Ministry of Aircraft Production in 1942 [censored] Gavin Bailey -- Another user rings. "I need more space" he says. "Well, why not move to Texas?", I ask. - The ******* Operator From Hell |
#2
|
|||
|
|||
|
#3
|
|||
|
|||
The Revolution Will Not Be Televised wrote:
On Mon, 18 Aug 2003 20:39:22 GMT, Guy Alcala wrote: Let's just say my reply has been delayed, but here goes. [snip more gratuitous and unprovoked logical discourse. NB all gallons referred to in this post are Imperial, not the inferior Yanqui oppressor's titchy competitive effort.] [Quill on longitudinal instability on Mk Vs] snip Much like the behaviour of the actual Mk IX/XVIs with rear-fuselage tanks in 1945. True, but those Mk.IX/XVIs also had extra fuel in the regular fuselage tanks (ca. 94-96 gallons, depending on the source) forward of the datum. 66 or 75 gallons according to the Pilot's Notes and Shacklady & Morgan. I was referring to the increased tankage forward of the firewall. And correct me if I'm wrong, but ISTR that only those a/c with cut-down rear fuselages got the aft tanks; Nope: the standard fuselage versions actually got larger internal rear fuselage tankage - 75 vs 66 gallons. At least that's what the Pilot's Notes say. [BTW, the VII/VIII/PR.X Pilot's Notes have some range/climb/cruise graphs which I think might be relevant to this discussion] Yes, you're right about the aft tanks. OTOH, those a/c with cut down rear fuselages also had increased forward fuselage fuel and in some cases leading edge tanks (according to several sources which I take to be credible), and I think larger horizontal tails, so clearly they wanted to move the Cg back forward again (more fuel forward, less aft) and improve the stability. For instance, here's a post from a couple of years back on this subject: ------------------------------------------------ The Pilot's notes state the following tankage: The Spitfire 1/II/V had 85 gallons of internal tankage, in two tanks behind the engine and in front of the pilot. Additional fuel was carried in 30, 45 or 90 gallon "slipper" tanks under the fuselage. These were in common use after 1941. Early Spitfire IX's had the same internal tankage, while at the end of 1944 a further 75 gallons of internal capacity in rear fuselage tanks was provided. This caused CoG problems as described, but in reality they seem little worse than those experienced in USAAF Mustangs using a similar rear-tabkage arrangement. In late model Spitfires with tear-drop canopies (late '44 production), the front tankage was increased to 95 gallons while the rear fuselage tankage was reduced to 66 gallons (for roughly the same total tankage). Also, late production Spitfires had the leading-edge wing tanks used in the Mk VII/VIII for an additional 26 gallons of internal capacity. From mid-1944, the existing slipper tanks were augmented with longer "torpedo"-shaped drop tanks with a 50 or 90 gallon capacity. Spitfires operating in 1944 seem to have used the latter tanks very frequently, judging by the photographic evidence. The Spitfire VII & VIII formed the airframe basis for the later production Spitfires, and apart from some early Mk XII Spitfire's converted from Mark V's, all Mark XII and Mark XIV Spitfires had similar tankage arrangements of 96 gallon forward internal tanks and 26 gallons in wing tanks. Later Mark XIV and Mk XVIII Spitfires had rear fuselage tanks, either of 62 gallons capacity. Early Mark XIV's (examples in the RB-serialled series at least) did not have rear tanks, and seem to have had Mark VIII-arrangement (with reduced forward tankage capacity previously mentioned) and I suspect the rear fuselage tanks only arrived with the later production Mk XIVe models, again after mid-1944. Some examples of the Spit V had a smaller rear tank, though I believe this was used for ferry only. That's correct. The CoG issues were regarded as insurmountable until larger tail surfaces arrived with the Mark VIII and later-production Mark IX's. This is a bit suprising as the Mark V rear-fuselage ferry tank carried 29 gallons, while flight testing of a Mark IX with the 75 gallon rear-fuselage tank indicated that the lateral instability associated with the extra tankage eased considerably after 35 gallons had been used, taking the remaining capacity close to the earlier 29 gallon tank level. This of course is a comment made in ignorance of the physical positioning of the tank, which would have the biggest impact on the CoG and consequent stability of any one factor. -------------------------------------------------------- You may recognize the poster's style, although he's since undergone a revolutionary reincarnation ;-) snip The Mustang could only retain a fraction (ca. 25-50%) of that rear tank fuel to use for combat without being dangerously unstable, with the contemporary Spit possibly (probably?) being unable to retain any of it; Actually, the relevant testing in January 1945 revealed that the acceptable manoevering limit with the 75-gallon rear fuselage tank was 9.9 inches aft of the datum, or after 34 gallons had been used. Clearly the tank didn't need to be emptied for this to be achieved. at best, it could retain the same fraction as the Mustang. The Mustang with rear tank didn't have 269 U.S. gallons to fight and return on; it had somewhere between 205 and 227, depending on what fraction of the aft tank capacity allowed acceptable combat handling. In this case we have a Mk IX with 85 gallons internal forward tanks and about 40 gallons in the rear tank within apparently tolerable limits for combat. With which tail, and did the a/c have leading edge tanks? To be an acceptable long-range escort, the Spit still needed the extra forward fuselage fuel of the later Mk. IXs and the Mk. VIIIs, plus the leading edge tanks of the latter. The Mk. VIII carried 124 Imperial gallons internally (149 U.S), ALL of which was usable in combat, plus whatever extra fuel usable in combat (if any) a rear tank provided. Ah, here we disagree: as far as I know, most IX/XVIs didn't have enlarged forward tanks (in the traditional position forward of the cabin bulkhead, behind the engine), and most MK VIIIs seem to have been similar. So the best reliable figure for the internal capacity of the Mk VIII would actually be around 110 Imp galls. I suppose Air Commodore Alcala, Director of Fighter Operations in this scenario, will be pressing the Air Member for Research and Development to get them all with the enlarged forward tanks as well.... Every source I have implies or claims that all Mk. VIIIs had the bigger forward fuselage tanks, but I'm willing to be convinced otherwise. But the tank size increase, according to a different poster from a couple of years ago, was something that could be done on any Mk. VIII or IX -- the space was always there, it just hadn't been used. Oddly enough, http://www.fourthfightergroup.com/ea...9tactical.html which contains the tctical trial data for AB 505 from April 1942, (i.e. prior to the testing of AB 197, which had the usual 85 gal.), states that "25......... The fuel capacity of the Spitfire IX is 92 gallons, 57 in the top tank and 35 in the bottom tank. This is 10 gallons more than the Spitfire VC." [increased tankage of 2 Spits IXs from Wright Field, July 1944] In the case of the Spit wing it seems to have been a strength issue, at least according to Quill Yes, but I suggest what Wright Field did was a reliable indicator of what the USAAF would have done if Spitfire production and procurement was within their grasp. A&AEE whinges about instability would get short shrift in this situation. Oh, I don't know. They found it impossible to increase the tankage of the P-39/P-63 for Cg reasons, and those a/c certainly could have used it in our service (it didn't matter to the Russians, but that was due to local theater conditions). . So I suggest basic experience of rear-fuselage tankage, and measures to combat the worst CoG issues resulting were at hand in plenty of time to have an impact on the postulated fitting of rear-fuselage tanks in the summer of 1943. The difference being that the flights to Gibraltar were ferry flights, and no formation maneuvering or combat flying with the aft tanks full was required. Sure, but how different is this from Vcs emptying them on the climb out of East Anglia and the cruise out to Holland? The short-ranged Spit Vs and IXs could handle combat in those areas, while the LR Spits would be briefed to pick up their escorts further out over the Zuider Zee. Giving them an extra 30-45 minutes of flight on internal fuel, even with the most restricted utility (e.g. only on the way in, no combat endurance to remain after entering combat) is still of use, and reflects the utility of giving them drop-tanks to start with. The final determinant is the distance over enemy territory a Vc could return on forward tanks alone after exhausting the rear tank, dropping the 90-gallon drop-tank and spending 10 minutes at high throttle settings in combat. This is obviously *not* a profile which makes it contender for deep-penetration escort, but it still means they should be able to operate out across Holland beyond Amsterdam and up to the German border. Even a marginal improvement like this would have had a real and clearly-observable benefit in supressing bomber losses. If the fuel in the external drop tank(s) is already roughly equal to the internal capacity needed to return, as it was with the 90 gal. tank, adding extra internal fuel that can't be used in combat does nothing for the combat radius, which is what we're interested in. Zemke makes this point with regard to the carriage of 2 x 108 USG tanks on P-47s prior to the D-25 models. All the earlier versions had 305 USG internal, and the switch from a single CL 150 (nominal) USG tank to a pair of 108s did little or nothing to extend the radius, although it did boost the endurance in the same area. zemek says that average fuel burn on escort missions was around 200 gal./hr., giving them at most about 90 minutes on internal fuel (this is with some combat allowance). Only when the D-25 and subsequent models entered service with the 65 gallon rear fuselage tank did the extra external fuel give an increased radius. Presumably most of this 65 gallons was usuable within Cg limits. Since it took quite a while for them to replace all the earlier models, even in the 56th, the extra radius couldn't be used for a long time. In the end, even the RAF cleared the rear-fuselage tanks for production usage in 1945, and they were happy enough to fit half of the tankage in the FR XIV and the full thing in the XVIII. Again, both a/c with cut-down rear fuselages. Yes, but the cut-down fuselage doesn't seem to be a factor in deciding whether a Spit got rear-fuselage tanks or not: the IX and XVI with conventional fuselage got them, the FR XIV got them and I suspect the XIV would have got them if it hadn't been succeeded on the production lines by the XVIII in 1945, which only came in a cut-down fuselage version. As it was, the example of the FR XIV and the IX/XVI indicates the cut-down fuselage actually had a lower capacity for rear-fuselage tankage (66 vs 75 gallons). See the two-year old post above, which indicates measures to move the fuel and Cg forward on these a/c. Getting to our respective readings and conclusions on Quill, I note that he says in the case of the Mk. 21 that he disagreed with A&AEE on whether the Mk. 21's handling was acceptable at a certain point, and that he felt that such handling deficiencies could be accepted to get an a/c with superior performance into the field (he's also man enough to admit that he may have been overconfident by this point that average squadron pilots wouldn't have had serious difficulties, based on his own skills). I suspect A&AEE were right on that point; but it's instructive to see, yet again, that Quill states a fix for the stability and trimming issues that plagued the F.21 in 1944 was known about (enlarged tail surfaces), but production issues ruled it out until 1945. Take the MAP monkey off Supermarine's back, demanding production at the expense of development all the time, and this and a lot of other relevant problems could have been dealt with earlier. Certainly what we intended to do, with range extension pushed to priority one. Would you happen to know what the production of Mk. VIIIs was in say October through Dec. '43, or maybe Jan. '44, inclusive? I'm thinking that a move like Arnold's (he gave the ETO _all_ P-38 and P-51 production for a three month period in late '43), giving Fighter Command all the Mk. VIII production in that period, would be enough to get us going. The MTO and everyone else will just have to accept Mk. VC Trops and/or Mk. IXs for a while longer (they were already using them in any case). Now, it may just be a question of him not thinking to mention it, or the way he worded it, but he maentions no such disagreement between himself and A&AEE regarding the handling of the rear fuselage tank-equipped a/c; he just says that the handling wasn't acceptable for a long time, and required a lot of development. The origin of the "acceptability" comments over the rear-tank tests appears to be Supermarine's development testing. Aircraft would only go to A&AEE after they had arrived at what they saw as a production standard (e.g. Quill testing the 75 gall RF tank in July 1944, but Boscombe Down not getting it for another six months). Also, note that the A&AEE testing was not a peacetime acceptance test as such - the aircraft and fittings involved were often ordered into production anyway to minimise delays to production totals, and A&AEE testing was often being performed as representative of current or imminent production. F.21's were actually being produced before and after A&AEE first critically reported on them. And Quill mentions that the F.21 a/c which A&AEE finally accepted had its handling much improved over the original version he was trying to get them to accept. I'm certainly not going to claim, based on such flimsy evidence, that this is definitive proof that the a/c couldn't have been flown in operations with an aft tank with accceptable handling much earlier given sufficient motivation, especially given your comments re the prevailing attitude of the A&AEE. But I do think it at least suggests that the Cg problems were real and agreed to be so by both the A&AEE _and_ Quill. And that's as far as I'm prepared to gaze into my crystal ball. Your reading may well be different. And it is, I'm afraid. A&AEE seem to get their first rear-tank Spit in January 1945, and quantify it as acceptable once 34 gallons out of the 75 were used. Nobody was going to Boscombe Down and pushing this idea, the whole issue seems to come from Supermarine. Posit a burning interest in the Air Ministry in increasing inernal tankage in 1943 (e.g. ACM Kramer getting upset) and I suspect things would have been remarkably different. Pete and I certainly hoped that would be the case, although I don't know that the rear tankage was critical. As long as we could get standard Mk. VIIIs (or LE-tank Mk. IXs) for the initial day transition period (France/Low countries/Ruhr/German coastal targets), if the Spit aft tank was taking too long Mustang production would probably cover our needs (as well as those of the U.S.) by the time we were ready to go deep. And then we'd be on the continent, and it would become almost a non-issue. snip then either expanding Mk. VIII production at the cost of the Mk. IX That would have been possible, but only at the point of converting Castle Bromwich over to the VIII in the summer or autumn of 1943. This needs a demonstration of the effectiveness and need for it somewhat earlier: hence my LR Vs in 12 Group in July. See Pete's post Mk. V Cg range. or (if possible) transitioning to Mk. IXs with the extra leading edge tanks of the VIII, with aft fuselage tanks and whatever airframe mods required to pack usable _combat_ fuel in. That would have required prducing the VIII wings & airframe, I believe, rather than stuffing a Merlin 60-series into a Vc airframe as was done to churn out IXs. So I think there would be production infrastructure issues. As it was, the Supermarine production group around Eastleigh delivered about 90 Mk VIIIs to the RAF in July 1943, which should be enough to prove the concept if you grab them all. That's what we want, say 6 squadrons worth of Mk. VIIIs to start with. Sure, and that with an aft tank was next on the agenda after boosting production of the standard Mk. VIII/leading-edge tank Mk. IX. Either of the latter should have given us an escort radius of 250-300 miles. See my note on the actual forward-tank capacity of most VIIIs. Although this may have been changeable. And see my comments. Unfortunately, a similar chart for a Mk. V doesn't seem to be available on the site, but I have my doubts that the Mk. V was carrying around any such ballast in 1943, or if it did, so far aft. Of course, AB197 was a very early Spit IX (the report date seems to be June 10th, 1942), so that ballast was probably reduced as more operational equipment was added, but it at least suggests (combined with the Mk. V's further aft Cg vs.the Mk. IX as reported in various tests on the site) that the Mk. V was pretty much at the limit, while the Mk. IX had considerably more Cg range available. I can't find anything to substantiate this with the V myself, and I understand the validity of your reservations. Nevertheless, the critical issue as I see it is whether any rear tankage could become available given improvements in the CoG by means of the enlarged elevator horn balance and convex Westland elevator. I fully accept this would, in all probability, have been insufficient to allow a 75 gallon rear-fuselage tank to be carried and cleared for combat. The critical issue is whether this would have been enough to permit a rear-fuselage tank to be used in the early stages of flight to extend the pre-combat range. Given that this was done with a 29 gallon rear tank, I think there is a useable margin, albeit a smaller one than a LR-fitted Mk VIII with better weight distrubution and enlarged tail surfaces would have. See Pete's post, which seems to confirm my reservations. I'm focusing on using the V not because it had more or even comparitive utility with the Alacal/Stickney LR Mk VIII (something I've argued for in the past myself), but because even with the greater constraints involved, it was a more likely concept-demonstrator in the historical timescale. If you want an overnight conversion to LR Spit IXs at any given point without the example of a LR operational trial in the RAF to start with, you'd have to posit the removal of most of the higher command and their staff involved to eliminate their existing preconceptions and prejudices. Well, we're already postulating that Winston has tossed most of the CBO out the window and told Butch to knock off most of the area bombing and switch to days, so existing prejudices have already been overturned. There'd still likely be a rearguard action, but it would be difficult to sustain when those 'action this day' prayers start being delivered to Portal on down. So this is why I think LR Vs would be an issue worth consideration even taking into account their inferiority from all aspects of the job when compared to the VIII. I think it's more credible to posit changes in the Vs proving the concept, as this would be more institutionally tolerable. This is important from my point of view, as I think any counter-factual speculation has to be made within the known constraints of the industrial, economic and institutional context to remain credible. I accept the idea, but retain my caveats over Cg, now strengthened by Pete's comments. [production pressures] I don't underestimate the pressures, I just think (as you mentioned a few paragraphs above) that if the decision had been made to go over to daylight, fighter range extension would have increased in priority and changes would have to have been accepted, whatever the disruption elsewhere. Because otherwise, it wasn't going to work. Indeed, but when the RAF actually faced this dilemma, at the end of 1939 and then again in spring 1941, they abandoned daylight bombing. The two concepts had become divorced, for understandable external reasons, and asserting a sudden and complete reversal of this is stretching the credibiluity of the institutional appreciation involved in the speculation. Now I think the concept is possible, and a valid piece of historical speculation, but I also think it has to work within the context involved, and, frankly, anybody demanding a reduction in Spitfire production in favour of speculative operational development was on a losing wicket. The British strategical position in this respect can't be overstressed too much: the USAAF had a doctine and institutional ambition towards independence which was served by the 8th AF campaign, secured by other forces doing things like protecting their bases and dealing with the existing war against Germany. They had room to stop and rethink tactics and strategy, and change production priorities accordingly. The British did not have this space. They had to maintain existing commitments and fight the war as it existed from a smaller industrial and economic base closer to the enemy threat. Proving strategic concepts, even ones which had great war-winning potential, was a luxury that could not come at the expense of the means for repelling the enemy in the meantime. The RAF could not prejudice production of their main fighter when it was needed for home defence, operations in the MTO and Far East and supply to the Russians. The difference between these commitments and facilitating daylight strategic bombing was the difference between fighting the war and demonstrating an abstract concept. Whatever happened in the skies over Germany, Fighter Command were conceiveably in a position to lose a war for national survival. The 8th AF wasn't. No lack of respect intended. The 8th might prove vital in winning the war, but high Spitfire production was known to be needed meanwhile to avoid defeat and stay in the war, which was an essential prerequisite. I don't agree that was the case by mid '43. Under no conceivable set of circumstances could Fighter Command lose air superiority over the UK then. As it was, Fighter Command was over-manned and equipped, and as you have yourself stated, under-utilized. What happened in Burma and in the Italian campaign weren't going to decide the war, and the Russians could have survived quite well without Spitfires. If nothing else, we could have produced more P-39s/P-63s, which in any case were etter suited to conditions on that front. snip areas of agreement or mild disagreement Please desist from this moderate rationality or I will complain to your ISP. Did I mention that I have INCONTROVERTIBLE PROOF that the U.K. government has been testing UFOs ( and dissecting ALIEN CORPSES) at their base at Machrihanish, Nah, you're just confusing Alien corpses with the average westie. Understandable mistake. We only retain them to give the midges a round-the-year locally-available food supply until the German tourists appear in the summer. cleverly disguising test flights of same as those by Aurora and, in times past, SR-71s? Wait, I hear the black helicopters coming to get me. I can feel the beams as they try to alter my brain. Excuse me while I done my tinfoil hat. Interesting theory, although it lacks credibility, until we acknowledge the critical role played by the Templars and the Illuminatii in the Ministry of Aircraft Production in 1942 [censored] That would explain the Templars' intimate knowledge of Spitfire fuel tankage, as reposted well above ;-) Guy |
#4
|
|||
|
|||
In article , The Revolution Will Not
Be Televised writes They all had facility for 2 pilots, e.g. extra controls could be fitted to the Halifax and Lanc if neccessary, but basically they had ceased to be 2-pilot aircraft by 1943. I'm not sure if they were intended to be operational with two pilots, I've only ever seen references to an extra set of controls if required, presumably mostly for training (although all the sources I have suggest training was done with only one set of controls). Most sources seem to suggest movement to/from the nose was awkward enough without extra controls getting in the way. Even for daylight ops, I'm not sure if a second pilot would have been carried, maybe the flight engineers would have received additional training (as some did unofficially from their pilots). I'm not sure when autopilots became common equipment (1943 perhaps?), they'd take some of the workload off the pilot. -- John |
#6
|
|||
|
|||
The Revolution Will Not Be Televised wrote:
On Wed, 20 Aug 2003 08:42:55 GMT, Air Commodore Guy Alcala, Director of Fighter Operations wrote: Isn't rapid promotion in wartime wonderful? And to think, I was just a lowly Wing Commander on Butch's staff a month or so ago, along with then Group Captain Stickney. snip Yes, you're right about the aft tanks. OTOH, those a/c with cut down rear fuselages also had increased forward fuselage fuel and in some cases leading edge tanks (according to several sources which I take to be credible), and I think larger horizontal tails, so clearly they wanted to move the Cg back forward again (more fuel forward, less aft) and improve the stability. Ah, but the tankage juggling didn't happen quite as sequentially and in such a comprehensive fashion. These things were much more piecemeal than an overall summary makes them appear. A comprehensive history of the modification states at and after delivery of all Spitfire models would be nice, but frankly it seems like a task better left to candidates for extensive residence in purgatory. Reviewing some of the "here they are, now they're gone" tank capacities in the A&AEE test reports on the 4th FG website, I'm beginning to think you're right. For instance, here's a post from a couple of years back on this subject: Well, this chap seems to talk some sense for once in this thread....[cough] In late model Spitfires with tear-drop canopies (late '44 production), the front tankage was increased to 95 gallons while the rear fuselage tankage was reduced to 66 gallons (for roughly the same total tankage). That's not entirely true, although I do enjoy the rueful pleasure of hoisting myself with my own petard. I don't think it's possible to definatively state that all RF-tanked Spit IXs had increased forward tankage. There's no reason this can't be the case in the ATL we're considering, though. The Spitfire VII & VIII formed the airframe basis for the later production Spitfires, and apart from some early Mk XII Spitfire's converted from Mark V's, all Mark XII and Mark XIV Spitfires had similar tankage arrangements of 96 gallon forward internal tanks and 26 gallons in wing tanks. Again, this seems to be out, based on my understanding as it has evolved over the past couple of years. Indeed. -------------------------------------------- AFDU Wittering July 1943 Spitfire XIV JF317 SHORT TACTICAL TRIALS OF EXPERIMENTAL SPITFIRE XIV INTRODUCTION On instructions from Headquarters, Fighter Command, an experimental Spitfire XIV JF317 (Griffon 61) was made available by A&AEE for three days for short tactical trials. The trials took the form of a direct comparison with a Spitfire VIII (Merlin 63) JF664, and flying took place from 27 to 29 July 1943. BRIEF DESCPRIPTION The aircraft used is a conversion of the Spitfire VIII. The larger engine involves a much longer engine cowling and the extra weight forward has been balanced by ballast in the tail. The fin has been increased in area to help directional stability and a large rudder is fitted. This aircraft had the normal span wings of the Spitfire VIII with small span ailerons, but the extended wing tips had been replaced by the standard wing tips as on the MK IX. The engine is not representative of production as the FS gear is higher and the MS lower. A five blade propeller is fitted. The engine had a Bendix injection carberator and boost for combat is limited to plus 15 lbs. The Spitfire VIII weighed 7,760 lb, the XIV 8,376. snip Range and Endurance- Both aircraft carry the same amount of fuel (96 gallons in the main tank and 27 gallons in two wing tanks.) Refueling checks made to compare consumption showed than when the two aircraft stayed together throughtout the trials, the Griffon engine was using approximately 10-15 gallons more fuel per hour than the Merlin. ----------------------------------------------------- So it appears that the "standard" Mk. VIII as well as the Mk. VIII(G) conversions did indeed have an internal capacity of 123 gallons, as early as July 1943. But then the weight and loading data for the second _production_ Mk. XIV, RB. 141, dated 15 Dec. 1943, state that it has 112 gallons, 85 in the fuselage (i.e. the original fuselage tanks) plus the 27 in the wing L.E. Just to confuse things, there's the later test below: ------------------------------------------------------- INTRODUCTION 1. In accordance with instructions from Headquarters, A.D.G.B., tactical trials have been completed on Spitfire XIV. Aircraft No. RB.141 was delivered to this Unit on 28.1.44 for comparative trials with the Tempest V. It was discovered that this aircraft was not representative of production aircraft for Squadrons, and Spitfire XIV No. RB.179 was made available and delivered on 25.2.44. The operational weight with full fuel and ammunition is 8,400 lbs. To give a clear picture to the greatest number, the Spitfire IX (maximum engine settings +18 lbs boost, 3,000 revs) has been chosen for full comparison, and not the Spitfire XII which is a low altitude aircraft built only in small numbers. Tactical comparisons have been made with the Tempest V and Mustang III, and combat trials have been carried out against the FW 190 (BMW 801D) and Me 109G. snip TACTICAL COMPARISON WITH SPITFIRE IX 13. The tactical differences are caused chiefly by the fact that the Spitfire XIV has an engine of greater capacity and is the heavier aircraft (weighing 8,400 lbs. against 7,480 lbs. of Spitfire IX). Range & Endurance 14. The Spitfire XIV, without a long-range tank, carries 110 gallons of fuel and 9 gallons of oil. When handled similarily, the Spitfire XIV uses fuel at about 1 1/4 times the rate of the Spitfire IX. Its endurance is therefore slightly less. Owing to its higher speed for corresponding engine settings, its range is about equal. For the same reasons, extra fuel carried in a long-range tank keeps its range about equal to that of the Spitfire IX, its endurance being slightly less. ------------------------------------------------------------ Now, was that 110 gallons a misprint, a rough rounding (seems unlikely), representative of the "standard" production a/c (details of differences not given) as opposed to the "non-standard" RB. 141, or just Supermarine fitting in whatever tanks they happened to have on the shelf on any particular day? Later Mark XIV and Mk XVIII Spitfires had rear fuselage tanks, either of 62 gallons capacity. Note that the FR XIVs, with cameras in place of one of the RF tanks, still had the second 33 gallon tank. I think RF-tanked Mk XIVs can't be dismissed out of hand. But one maniacal idea at a time. Brng it up again and it's off to Wandsworth with you, for sabotaging the war effort. You may recognize the poster's style, although he's since undergone a revolutionary reincarnation ;-) Via a publically-acclaimed stint as a German emperor's hairstyle... Nonetheless, it's a reasonable summary but I think the forward tank size is probably not representative. The Pilot's Notes for the Mk XII give a standard 85-gallon forward tankage, the PN's for the F.21 give it the same tankage and ditto for the Mk XVIII. Interestingly enough, the tactical test of the Mk. XII EN. 223 in Dec. 1942 includes the following comment: ------------------------------------------- Flying Characteristics 5. In the air the handling of both EN.223, and another production Spitfire XII which was made available by Supermarine for one day, were felt to be far superior to the normal Spitfire IX or VB, being exceptionally good in the lateral control which is crisper and lighter due to the clipped wings. The longitudinal stability is much better than that of the Spitfire V, and in the dive it was particularly noticed that when trimmed for cruising flight, it stays in easily at 400 m.p.h. I.A.S., and does not recover fiercely. In turns the stick load is always positive and the control very comfortable. ----------------------------------------------- Also "It is fitted with facilities for beam approach and about the first seven, including the aircraft on trial, have the oil tank behind the pilot. This is not acceptable operationally and subsequent aircraft will have the oil tank mounted immediately aft of the fireproof bulkhead. The fuel capacity is retained at 85 gallons, and jettison tanks can be used if required." Moving the oil tank forward would of course shift the Cg in the same direction, boosting the stability even more. Both of the latter were definative production versions, with plenty of time to include larger forward tankage in the production lines if it had been decided upon as a production version requirement. The PN's for the VII/VIII/X do refer to an increased 96 gallon forward tankage, so you're right and it would be valid for the Merlin LR Spit, but not for the Griffons, I suspect. So it seems, from the Mk. VIII/conversion Mk. XIV test quoted above, and the various Mk. XIV prodution tests.. In this case we have a Mk IX with 85 gallons internal forward tanks and about 40 gallons in the rear tank within apparently tolerable limits for combat. With which tail, and did the a/c have leading edge tanks? Vc tail, no leading edge tanks. I think we can summarise on a LR Spit VIII having the following: 96 gallons internal forward tanks (47 and 49 gallons) 25 gallons internal wing tanks (two 12.5 gallon tanks; conservative figures used) The Spit VIII srs ii a.k.a. Spit LR VIII gets this extra - 75 gallons internal rear fuselage tank. This gives a potential internal fuel capacity of 196 gallons, with a further 90 available from external slipper or drop tanks. How this translates to range might be worth exploring. Much of this is pure conjecture on my part, I should add, and please correct me if you have a better idea of the figures involved. The PN's for the VIII give an allowance of 9 gallons for run-up and take-off. That should be out of the rear tank. Depends. For safety reasons it's more likely to be from one of the main tanks, so as to avoid any fumbling during takeoff if there are feed problems. I'm assuming that all the drops, aft fuselage and L.E. tanks all feed into one of the main tanks, like the Mustang. I don't know the details of the Spit's fuel plumbing. Climbing at 160 IAS (if I'm assuming this correctly from the curves given) should take perhaps 15 gallons and maybe 15 minutes to 25,000 feet on a low revs weak mixture. The performance curve I'm looking at only covers a clean aircraft, so an extra 5 gallons or so to cover the higher weight might be reasonable. I'm assuming wing rendezvous and assembly could be done on the climb phase, if not let's assume another 5 gallons. This knocks off 34 gallons from the rear tank, and should mean the aircraft is reasonably stable when they depart the English coast. I imagine the rest of the profile would be flown at a low-revs, high-boost weak mixture cruise. That could go down to 1,800 rpm, but then there's the tactical need to maintain a high airspeed. I suggest your wing commanders cruisie at 2,200 rpm and +4 boost, for a consumption of 61 gallons per hour. That should give about 6.5 air mpg, or maybe 6 when the drag of the external tank is taken into consideration. What kind of air speed does that give you? Zemke says that they normally cruised at maybe 210-220 IAS on Rodeos (doesn't say specifically what the cruise was on Ramrods), giving 320-325 TAS at escort altitudes. There obviously needs to be a contingency reserve on the internal forward fuel, maybe 10 gallons as a minimum. This gives us 24 gallons in the wing tanks, 86 usable in the forward tanks, 41 left in the rear tanks and 90 in the drop tank. The priority would be to expend fuel in the tanks which cause performance degredation, so the rear and drop tanks would have the priority. We'd have to assume a minimum of 10 minutes at full combat settings for the engine, which at +18 lbs and 3,000 rpm (even if it might not attain this in high-altitude combat, I want to be conservative). At 150 gallons per hour, this means as much as 25 gallons being used in combat, and this must come from the internal fuel. So the internal fuel situation is looking like 34 gallons for climb and assembly from the rear tank, a 10 gallon reserve from the front tanks (the last to be emptied and the ones you'd be on when stooging about East Anglia in the fog desperately seeking somewhere to land) and 25 gallon allocation for combat from the same tanks. This leaves 41 gallons in the rear tanks and 76 gallons in the wing and forward tanks, not including 90 in the drop tank. The remaining 117 gallons of internal fuel should give a still air range of about 700 miles, or about 350 miles radius under good cruising conditions. The 90 gallon tank should give a further still-air range of 500 miles or so, but none of that can be relied upon as it will be jettisoned at the first sing of combat. The range on internal fuel is more impressive than I thought. The drop tank would be useful getting across the North Sea, and as the USAAF demonstrated, could be held on until German fighters were spotted long past the enemy-held coast, and so the internal fuel would really only be needed for combat and returning from combat. If these figures (admittedly from a "back of fag packet" provenance) have any pretence at being representative, it seems the Director of Fighter Operations (Air Commodore Alcala) and the Air Member for Research and Development (AVM Stickney) might be on to something here. The Spit LR VIII might well have been very useful as an intermediate-range escort. I think some of your assumptions are a wee bit optimistic for Wing-size ops, but agree with the general tenor. Every source I have implies or claims that all Mk. VIIIs had the bigger forward fuselage tanks, but I'm willing to be convinced otherwise. I'm not going to push that angle: it seems a reasonable enough assumption on the basis of the evidence I have. But the tank size increase, according to a different poster from a couple of years ago, was something that could be done on any Mk. VIII or IX -- the space was always there, it just hadn't been used. Oddly enough, Some IXs did get it, but I can't discover the logic or process involved at this stage. I increasingly wonder if it was a matter of "whatever the subcontractors deliver today." Any idea who made the internal tanks (if not Supermarine), and if there was more than one company involved? which contains the tctical trial data for AB 505 from April 1942, (i.e. prior to the testing of AB 197, which had the usual 85 gal.), states that "25......... The fuel capacity of the Spitfire IX is 92 gallons, 57 in the top tank and 35 in the bottom tank. This is 10 gallons more than the Spitfire VC." That's interesting, as it's not the actual VII or VII forward tank profile (47 gallons top and 49 gallons bottom). This might be an unrepresentative example. I think the VIII capacity is plausible enough, and they began production in November 1942. Yeah, I have no idea where the 92 gallons comes from, or how it can be considered "10 more than the Spit Vc." Yes, but I suggest what Wright Field did was a reliable indicator of what the USAAF would have done if Spitfire production and procurement was within their grasp. A&AEE whinges about instability would get short shrift in this situation. Oh, I don't know. They found it impossible to increase the tankage of the P-39/P-63 for Cg reasons, and those a/c certainly could have used it in our service (it didn't matter to the Russians, but that was due to local theater conditions). They did apparently stick a 43 gallon tank behind the pilot, which is interestingly enough when we bear in mind the 75 gallon tankage becoming tolerable after 34 gallons were used; i.e. taking it down to 41 gallons behind the pilot. I really think there is some valid mileage there, especially since MK210, the aircraft in question had normal Vc/IX tail surfaces, and not the Mk VIII extended tail which would have improved stability further. If the fuel in the external drop tank(s) is already roughly equal to the internal capacity needed to return, as it was with the 90 gal. tank, adding extra internal fuel that can't be used in combat does nothing for the combat radius, which is what we're interested in. Zemke makes this point with regard to the carriage of 2 x 108 USG tanks on P-47s prior to the D-25 models. All the earlier versions had 305 USG internal, and the switch from a single CL 150 (nominal) USG tank to a pair of 108s did little or nothing to extend the radius, although it did boost the endurance in the same area. I appreciate the distinction, but pre-combat endurance at the range limit is still an important advantage, especially in this scenario. I'm not asserting that an LR Spit could replace the longer ranged escorts like the P-38 and P-51. It could have moved out to Thunderbolt-radius, and that would have been a major benefit. While the early P-47 groups were complaining about range and endurance difficulties, they still did a lot of good work within their attainable radius. Agreed. It seems that the break point in practice for radius extension is reached when the external capacity is roughly 2/3rd of the (combat usable) internal. Beyond that you're just boosting the endurance or ferry range. snip Certainly what we intended to do, with range extension pushed to priority one. Would you happen to know what the production of Mk. VIIIs was in say October through Dec. '43, or maybe Jan. '44, inclusive? No, but the service acceptances by the RAF seem to be (by a hand and eye count of the appendices in Shacklady & Morgan, so I can't claim any real authority for these figures) about 90 in July 1943, 98 in October, declining to 67 in November, 53 in December and 28 in January 1944. This doesn't reflect production figures per se, as the aircraft had often been in storage for some time or were shipped to Casablanca or India, and had actually been produced earlier. But it does give an indicator of deliveries, which is almost what you want. We're in fat city, then, and I see no need to mess around with Mk. Vs. The October acceptances will allow us to form 3 squadrons immediately plus 50% reserves (ideally we'd want at least 100%), more than sufficient force for escorting the first 'Combat wing' of heavies we form in 3 Gp. Bear in mind there was a minor changeover to Mk XIV production (starting with 2 aircraft in October 1943, to about 7 per month in December 1943) at this point. Otherwise the Eastleigh production group under Supermarine were moving to producing Seafires and fooling about with XVIII and F.21 development (which would take aeons to culminate in a production version). The main production resource was Castle Bromwich, which was churning out Mk IXs at this point. I don't see why Mk VIII airframe production couldn't be extended and maintained at about 90 per month. That should be enough to operate 9 squadrons (on 20 a/c i.e. strength, 10 per month per sqn to replace losses) on a reasonable 50% per month wastage figure without even touching CBAF. As tanks become available, the CBAF IXs can mutate into VIIIs and then LR VIIIs. Seems reasonable, although we'd want to boost Mk. VIII production well above 90/month, to allow us to re-equip Fighter Command faster and supply the overseas squadrons. In the meantime, they get the Mk. IXs that we're not replacing with Mk. VIIIs. I'm thinking that a move like Arnold's (he gave the ETO _all_ P-38 and P-51 production for a three month period in late '43), giving Fighter Command all the Mk. VIII production in that period, would be enough to get us going. The MTO and everyone else will just have to accept Mk. VC Trops and/or Mk. IXs for a while longer (they were already using them in any case). Well, it looks like the real bottleneck is in fitting enlarged main tanks, wing tanks and rear fuselage tanks to the IX. I don't have the information to scale this into consideration, but I can't believe that tank production couldn't have been expanded. And Quill mentions that the F.21 a/c which A&AEE finally accepted had its handling much improved over the original version he was trying to get them to accept. Yes, they did: by early 1945, after production deliveries began in August 1944. In my version of this scenario, after appointing myself as Air Member for Production at the MAP and Air Council, I'm telling Supermarine to continue Mk VIII production and move the F.21 onto the back burner, although fighting for an allocation of Mk VIII airframes for conversion to Mk XIV offset from Castle Bromwich beginning production of LR Spit IXs with LR Mk VIII tankange to keep ACdr Alcala and AVM Strickney quiet. This gives us an interim two-stage Griffon version in service in February 1944 without all the dislocation caused by the arseing about producing unusable F.21s in the short term. An excellent plan. Pete and I certainly hoped that would be the case, although I don't know that the rear tankage was critical. Maybe not as much as I thought, but still, let's go for it as a Spit VIII series ii (Long-Range) standard to come in when possible. With ACM Kramer in charge that might happen a lot sooner than in OTL. Not to mention Winston pushing. I don't agree that was the case by mid '43. Under no conceivable set of circumstances could Fighter Command lose air superiority over the UK then. Well, we know that now, and I'm sure some did at the time, but don't underestimate the retentive power of the 1940-41 institutional and beurocratic memories, and the impact of the production priorities which were shaped then. As it was, Fighter Command was over-manned and equipped, and as you have yourself stated, under-utilized. What happened in Burma and in the Italian campaign weren't going to decide the war, and the Russians could have survived quite well without Spitfires. I'd say so as well, but the political ramifications were not easily dismissed. The Aussies, India Command, the DAF, the Americans and Russians had all asked for and been promised Spitfire allocations which were still required at the time. These all had to come out of Mk IX production. I don't think this is as big a problem as I'd initially assumed if the main bottleneck is building and fitting the internal tanks: there was no need to stop production meanwhile, even if there was a shortage of tanks to fit them all. Ah, but we're doing a direct swap, giving them Mk. IXs instead of Mk. VIIIs, just for a few months. As it is, 31st FG was flying a mix of Mk. Vs, Mk. IXs and Mk. VIIIs in Italy, so the U.S. would just have to wait on the Mk. VIIIs for a while. If nothing else, we could have produced more P-39s/P-63s, which in any case were etter suited to conditions on that front. I wouldn't disagree with that, but again, it's a judgement borne of hindsight. Nobody was going to emerge successfully unscathed from a Chief of Staffs meeting with Winnie present after voicing the suggestion that Russian allocation of British fighters be cut entirely. Hey, they can have all the Mk. IXs they want. That would explain the Templars' intimate knowledge of Spitfire fuel tankage, as reposted well above ;-) Wait till the German emperor's hairpiece turns up on Google with it's own unique contribution to make. Have I mentioned Sabre-powered Lancasters yet? Yes, you have, oh spawn of the devil;-) Guy |
#7
|
|||
|
|||
In article , Peter Stickney
writes In article , (The Revolution Will Not Be Televised) writes: On Wed, 20 Aug 2003 02:04:33 -0400, (Peter Stickney) wrote: SNIP lots That might be a reason for the Sutton Harness in a Spit- you wouldn't want the pilot leaning forward causing the airplane to nose down! The Sutton harness, because of that lousy pin-and-hole arrangement, was only ever capable of stopping pear-shaped people from moving around. RAF fighter pilots tended to be slightly slimmer... (Actually, I have doen this with light airplaes, to demonstrate the balance of forces to (captive audience) passengers - lean forward, nose down, lean back, nose up.) The refined version of this was carried out by a rugger team on a flight in a small airliner some years ago. While the stewardess was busy in the galley, the team members went to the back of the aircraft one by one (at a rate calculated by a pilot member of the team to make the pilot of the aircraft trim back slowly) and then at a given signal they all ran forwards again...yeeehaaaa! Cheers, Dave -- Dave Eadsforth |
#8
|
|||
|
|||
Peter Stickney wrote:
In article , John Halliwell writes: In article , The Revolution Will Not Be Televised writes They all had facility for 2 pilots, e.g. extra controls could be fitted to the Halifax and Lanc if neccessary, but basically they had ceased to be 2-pilot aircraft by 1943. I'm not sure if they were intended to be operational with two pilots, I've only ever seen references to an extra set of controls if required, presumably mostly for training (although all the sources I have suggest training was done with only one set of controls). Most sources seem to suggest movement to/from the nose was awkward enough without extra controls getting in the way. Even for daylight ops, I'm not sure if a second pilot would have been carried, maybe the flight engineers would have received additional training (as some did unofficially from their pilots). I'm not sure when autopilots became common equipment (1943 perhaps?), they'd take some of the workload off the pilot. It's not so much a question of workload as is is, uhm, having a backup pilot fully capable of flying a probably damaged airplane to a safe recovery. Yes, quite a number of Lancaster and Halifax FEs got stick time, but how many were practicing engine-out landings? For that matter, if you've got a damaged airplane, you want somebody to fly while the FE keeps things together. I'll disagree here. You want two pilots so they can take turns flying tight formation. For night ops it was no big deal to put the a/c on george and have the first and second pilots swap out (before they replaced the 2nd pilot with a FE). That's not an option when flying in a combat box. With only a single pilot the formations are going to be looser, and that's the last thing the Brit heavies need, as they're already going to be the ground bait. Once air superiority is won and the invasion has happened it's not as big a deal, becaue there's less need to fly tight formation for as long, but we're talking about the period before that occurs. Both Lanc and Halifax have FE seats next to (and slightly aft) of the pilot, so the space shouldn't be a too much of a problem. I wasn't aware that these two a/c had provisions for dual controls built in, although I knew that some had them; when we were trying to figure out what mods we'd have to make to run these a/c by day, we had allowed a fair amount of time to design and develop a production dual control system, so it seems that we were overcautious in estimating how much time that would take. Guy |
#9
|
|||
|
|||
On Thu, 21 Aug 2003 06:53:31 GMT, Air Commodore Guy Alcala, Director
of Fighter OperationsGuy Alcala wrote: Isn't rapid promotion in wartime wonderful? And to think, I was just a lowly Wing Commander on Butch's staff a month or so ago, along with then Group Captain Stickney. I'm still the only one of the three of us to appoint himself to the Air Council, so start bribing me now if you want me to rubber-stamp your promotion to Air rank. [96 gall forward tanks in Mk VIIIs reduced to 85 galls in Mk XIVs using Mk VIII airframes] [Snip AFDU report on Spit XIV] So it appears that the "standard" Mk. VIII as well as the Mk. VIII(G) conversions did indeed have an internal capacity of 123 gallons, as early as July 1943. But then the weight and loading data for the second _production_ Mk. XIV, RB. 141, dated 15 Dec. 1943, state that it has 112 gallons, 85 in the fuselage (i.e. the original fuselage tanks) plus the 27 in the wing L.E. Just to confuse things, there's the later test below: [snip next test report] Now, was that 110 gallons a misprint, Nope, you've now moved onto the next tankage problem: the wing tanks! Notice how I've been using a figure of 12.5 Imperial gallons for them? Well, their size seems to fluctuate from 12.5 galls up to 16-or even 18 in some later Spits. 12.5 seems to be the most common as this report bears out: 85 galls forward fuselage plus two 12.5 galls in the wing giving 110 gallons. a rough rounding (seems unlikely), representative of the "standard" production a/c (details of differences not given) as opposed to the "non-standard" RB. 141, or just Supermarine fitting in whatever tanks they happened to have on the shelf on any particular day? My impression, and it isn't any more than that, but it is nonetheless based on some limited research on 125 Wing which fielded the first Spit XIV sqns in 2 TAF, is that 110 is representative of the RB-serials delivered in late '43 and early '44. Note that the FR XIVs, with cameras in place of one of the RF tanks, still had the second 33 gallon tank. I think RF-tanked Mk XIVs can't be dismissed out of hand. But one maniacal idea at a time. Brng it up again and it's off to Wandsworth with you, for sabotaging the war effort. Listen, I'm all for your LR VIIIs, and I'm even helping by pushing for rear-fuselage tanks for them, but the quid pro quo is XIV production beginning on schedule, and the fitting of rear tanks to them whenever possible. Interestingly enough, the tactical test of the Mk. XII EN. 223 in Dec. 1942 includes the following comment: [snip better longitudinal stability characteristics than Mk V] No argument here. Although it did need a larger rudder. And so do we for the LR VIIIs, BTW. Moving the oil tank forward would of course shift the Cg in the same direction, boosting the stability even more. A couple of blocks of steel ballast might assist.... The PN's for the VII/VIII/X do refer to an increased 96 gallon forward tankage, so you're right and it would be valid for the Merlin LR Spit, but not for the Griffons, I suspect. So it seems, from the Mk. VIII/conversion Mk. XIV test quoted above, and the various Mk. XIV prodution tests.. Right, there's only so much of this outrageous agreement I'm prepared to stand. The PN's for the VIII give an allowance of 9 gallons for run-up and take-off. That should be out of the rear tank. Depends. For safety reasons it's more likely to be from one of the main tanks, so as to avoid any fumbling during takeoff if there are feed problems. I've just been thinking of this. Why not run the rear tank via a pump (or two for redundancy) to the main tanks to keep them full while running down the rear tank, just like the approach with the wing tanks? I'm assuming that all the drops, aft fuselage and L.E. tanks all feed into one of the main tanks, like the Mustang. The drops on the Spit didn't at this point, as far as I know. This caused problems involving fuel starvation when changing to main tanks. Notably for Al Deere and Buck McNair. Although this might have been down to vacuum problems in a common feed-line. I don't know the details of the Spit's fuel plumbing. Annoyingly, I can't find anything but main tanks and drop tank feed in the Pilot's Notes, so I don't know how the rear tank was handled. I imagine the rest of the profile would be flown at a low-revs, high-boost weak mixture cruise. That could go down to 1,800 rpm, but then there's the tactical need to maintain a high airspeed. I suggest your wing commanders cruisie at 2,200 rpm and +4 boost, for a consumption of 61 gallons per hour. That should give about 6.5 air mpg, or maybe 6 when the drag of the external tank is taken into consideration. What kind of air speed does that give you? 180 IAS according to the (rather small-scale) graph at 15,000 feet. It claims to be valid from 10,000-25,000 feet, but not fully accurate for rpm at different heights. Zemke says that they normally cruised at maybe 210-220 IAS on Rodeos (doesn't say specifically what the cruise was on Ramrods), giving 320-325 TAS at escort altitudes. By November 1942 the Spit Vs at least seem to be cruising at 300mph TAS at 20,000 feet when anticipating enemy contact. 2,400 rpm +4 lbs seems to have been one target setting recorded in some primary documentation I've seen from that time. 2,400 rpm at +4lbs would increase consumption to 66 galls per hour, but should permit (according to the graph) 200 IAS within the acceptable revs range. The Air mpg drops to 6, and we'd need to increase that consumption for external tank drag, but it doesn't change things much. The relatively low consumption of the Merlin seems to stand it in good stead there, but I've always thought the P-47 cruised faster. If these figures (admittedly from a "back of fag packet" provenance) have any pretence at being representative, it seems the Director of Fighter Operations (Air Commodore Alcala) and the Air Member for Research and Development (AVM Stickney) might be on to something here. The Spit LR VIII might well have been very useful as an intermediate-range escort. I think some of your assumptions are a wee bit optimistic for Wing-size ops Sure, but I don't think I'm wildly out, and the figures were good enough to be significant even with a fudge factor. , but agree with the general tenor. Some IXs did get it, but I can't discover the logic or process involved at this stage. I increasingly wonder if it was a matter of "whatever the subcontractors deliver today." Any idea who made the internal tanks (if not Supermarine), and if there was more than one company involved? Yes, there were several firms involved, some locally around Southampton. I think CBAF made their own. I don't want to investigate that nightmare much further. My own suspicion is that any aircraft reserved as a test-bed tended to perform several test regimes simultaneously and sequentially, going back and forth from Eastleigh to Boscombe or Farnborough and having minor non-standard modifications made on a constant, unrecorded basis. For example, one Spit being used by A&AEE for gun heating trials with all the modifcations involved would also have Supermarine sticking new fuel tanks in and repositioning the IFF set at the same time, and apparently off their own bat. No, but the service acceptances by the RAF seem to be (by a hand and eye count of the appendices in Shacklady & Morgan, so I can't claim any real authority for these figures) about 90 in July 1943, 98 in October, declining to 67 in November, 53 in December and 28 in January 1944. This doesn't reflect production figures per se, as the aircraft had often been in storage for some time or were shipped to Casablanca or India, and had actually been produced earlier. But it does give an indicator of deliveries, which is almost what you want. We're in fat city, then, and I see no need to mess around with Mk. Vs. This is where my political considerations kick in: the promises to the DAF, the 12th AF and the Russians and the Far East already exist and need to be serviced. Almost all the VIIIs being produced are being shipped out to overseas theatres. If you want the whole of Mk VIII production, when does this decision get made? My Mk V speculation was based on what would be likely with existing resources. 12 Group needed that range, and FC didn't give a stuff what they did with their Mk Vs (e.g. the LF Vb conversions at this time). Increasing internal tankage would be a small step to them, without major political considerations. I can only see this whole scenario working if FC actually have some resources capable of supporting a daylight effort; even the CAS can't complelely dictate operational tactics to an RAF C-in-C. The October acceptances will allow us to form 3 squadrons immediately plus 50% reserves (ideally we'd want at least 100%), more than sufficient force for escorting the first 'Combat wing' of heavies we form in 3 Gp. The actual political changeover point would be earlier: the British press, establishment and even some in the RAF were very impressed by aspects of the USAAF daylight bombing effort in the spring and summer 1943. It would really have to happen about then, before Schweinfurt I reinforced all their prejudices. I don't see why Mk VIII airframe production couldn't be extended and maintained at about 90 per month. That should be enough to operate 9 squadrons (on 20 a/c i.e. strength, 10 per month per sqn to replace losses) on a reasonable 50% per month wastage figure without even touching CBAF. As tanks become available, the CBAF IXs can mutate into VIIIs and then LR VIIIs. Seems reasonable, although we'd want to boost Mk. VIII production well above 90/month, I'd agree, but frankly you're hitting the limit of the relevant production resource, i.e. the Hampshire production group focused on Supermarine's dispersed work. You might get 120 or so out of them per month of they packed up everything else, bar a couple of PR Spits and the beginnings of the Mk XIV. The next focus I suggest would be getting Westlands, finishing off their Mk V production run with Seafires to move to Mk VIIIs while tackling Castle Bromwich. I think you could fully convert to Mk VIII-based production by spring 1944, with an increasing number of rear-tank versions available within that output, and with the Mk XIV entering service at the same time. to allow us to re-equip Fighter Command faster and supply the overseas squadrons. In the meantime, they get the Mk. IXs that we're not replacing with Mk. VIIIs. Seems reasonable. By this point the Burmese offensive has been put off for shipping reasons, and the 12th AF and DAF will be able to utilise bases on mainland Italy to support operations. This gives us an interim two-stage Griffon version in service in February 1944 without all the dislocation caused by the arseing about producing unusable F.21s in the short term. An excellent plan. It shunts the F.21 off until later in 1945, but if the strategic air offensive is to peak in 1944, we need the LR VIIIs we can get, and if we're going back into Europe we need more XIVs in the next 12 months than we need a slightly improved Mk XIV in 1945 at the expense of Mk XIVs usable for D-Day. And the Admiralty can make do with modified Mk LF Vbs for their Seafires, as their main fighter resources are going to be Hellcats and Corsairs, anyway. The RN only needs good deck fighters to take on the IJN, so it's in the political interest of the US government (if not in the interests of King's ego) to keep them supplied under Lend-Lease. This all actually sounds quite credible, the more I think about it. Maybe not as much as I thought, but still, let's go for it as a Spit VIII series ii (Long-Range) standard to come in when possible. With ACM Kramer in charge that might happen a lot sooner than in OTL. Not to mention Winston pushing. I think the political dynamic, i.e. when and how WSC starts pushing, needs some exploration. Ah, but we're doing a direct swap, giving them Mk. IXs instead of Mk. VIIIs, just for a few months. As it is, 31st FG was flying a mix of Mk. Vs, Mk. IXs and Mk. VIIIs in Italy, Likewise the 52nd FG: by spring 1944 and their conversion to Mustangs, they seem to be almost totally converted to MK VIIIs. That's about 140-150 Mk VIIIs, not to mention the couple of DAF wings that had them. so the U.S. would just have to wait on the Mk. VIIIs for a while. They would have been useful in 1943, but the peak for that would have been the extensive over-water operations associated with Sicily, Salerno and Anzio. They should be fine with Mk IXs in the short term after September 1943, with the added bonus of getting longer-ranged Mk IXs in the future. Same for the Far East. Uncle Joe can just get some of our extensive stock of Mk Vs, and when he actually asks for Mk IXs in early 1944, we can fob him off with the short-ranged versions. I wouldn't disagree with that, but again, it's a judgement borne of hindsight. Nobody was going to emerge successfully unscathed from a Chief of Staffs meeting with Winnie present after voicing the suggestion that Russian allocation of British fighters be cut entirely. Hey, they can have all the Mk. IXs they want. Provided we're getting enough LR IXs for the strategic campaign, 2 TAF and the DAF, that's fine. I think we'll be on 300 per month by this stage (total Spit production). That would explain the Templars' intimate knowledge of Spitfire fuel tankage, as reposted well above ;-) Wait till the German emperor's hairpiece turns up on Google with it's own unique contribution to make. Have I mentioned Sabre-powered Lancasters yet? Yes, you have, oh spawn of the devil;-) Well, it would just need the conversion of 55% of the total British industrial base to cover replacing the disintegrating sleeve-valves, and a further 2 million GRT of tanker tonnage to cover the extra oil consumption involved, but this is a small strategic price to pay for a fleet of Lancasters cruising at 275 mph at 18,000 feet*. Gavin Bailey [* For 5 minutes until the first engine failed.] -- Another user rings. "I need more space" he says. "Well, why not move to Texas?", I ask. - The ******* Operator From Hell |
#10
|
|||
|
|||
On Wed, 20 Aug 2003 22:46:44 -0400, Air-Vice Marshal Stickney, Air
Member for Research and Development, wrote: By all means, except I also note a depressing lack of nationalistic abuse in this post. Oh, well then, how's this: The last time a Brit tried to hand my family a line like that we threw his tea in the harbor. Now that was the kind of atrocity that should have featured in "the Patriot".... Still, an innovative approach to evading custioms duties and personal taxation which I'm sure is maintained as a family tradition under the IRS and the enlightened leadership of Lord Dubya of Shrub. Shame about Shay's rebellion, not to mention Sam Adam's interesting post-colonial take on sedition and the level of property ownership required to participate in a representative democracy. Ah, that feels better, now back to the mud-slinging of rational discourse. [rear fuselage tanks in Spit Vcs] That's going to take a lot of fiddly meaduring & figuruing to say for sure, but, looking over the inboard profiles (X-ray views) of both aircraft, one thing does stand out - a Spitfire's cockpit is aft of the wing, and well aft of the CG. And the fuselage ahead of the cockpit is already full of stuff. (Fuel, mostly) The available space behind the cockpit is a long way aft of the CG, which isn't good. A Mustang's cocpit is over the wing. The aft tank location is basically right at the trailing edge. Not only is the airplane more tolerant of how it's loaded, the tank location is in a better place. There's no denying it's a real problem. Agreed, but is this insoluable? The question doesn't appear as easily to definatively answer (either way) as it first appeared to me. Well, for teh Mk VIII and Mk XIV, it indeed was. FOr a Mk V, I'm not sure. See what you think over the sums when you get a chance. Actually, according to the A&AEE's reports on testing Mustang Is, and various Mk Vs, I don't see a whole lot of difference in altitude performance, even without the Mustang II's higher-supercharged engine. At 25,000 feet? There's no doubt the Alison Mustang was very useful below that height, but we need an escort force which performs well in the 20-25,000 or even 30,000 feet band. I'm dubious about the Mustang I in that environment, even more so with the Mustang II which I thought had a lower-altitude supercharger peak. It didn't climb as well as a Spit, adn it didn't quite turn as well, but it did out-speed, out-turn and out-zoom the Fw 190As that the Abbeville boys were flying. (Speaking of which, is Holly Hills still extant? I know he was recovering from his stroke a few years back.) Sorry, I don't know. Precisely. We need to posit a sufficient instiutional change of policy and interest to even begin this, but as nothing would happen without it, we might as well take it as a given. Well, I could begin my somewhat-factually based Nationalistic Rant about how the Brits, and Europeans in general never figured out how to put long range into fighter airplanes becasue their countries are so danged small, and that you can't ever be more than an hour from a National Border or coastline, unlike those of us who need to be able to fly stuff from San Francisco to Honolulu routinely, but I won't. Actually, I don't think that's sufficiently chauvanistic, in that I think there is a cultural dynamic relatesd to geography at work. However, the flip side of that is that the Europeans produced better interceptors in the early war period partly because of their willingness to cut weight (and fuel carried) to the minimum required for an area-defence fighter. Now I actually think the early US fighters (even the P-40 and P-39) were better than their later press made them out to be, but in this instance I think that for all it's shortcomings, the Spitfire in 1942-3 was the best type available in meaningful quantity for altitude combat, which is one reason the USAAF got it to replace the P-39. Getting more fuel into the Spitfire airframe, for all the difficulties, is a better option than trying to make the P-40 or P-39 a competitive high-altitude fighter. [2 pilot regime] The loading on the training infrastructure would increase, and the attritionally-supportable force would shrink, but then again BC took heavy casualties and expanded, and I'm not aware of a critical aircrew shortage: aircrew training slots seem to be over-subscribed since 1941, with pools of aircrew forming everywhere except in Bomber Command. The output of trained pilots is an issue, but then I'm not aware of it being inadequate historically. If anything, the British prioritised aircrew training too much in the period 1941-43 with repercussions elsewhere on the war effort (e.g. infantry replacements in 1944-45). It's a good question, though. If you suddenly start needing twice as many bomber pilots, the repercussions will be far & wide. Agreed, but look how many pilots BC were going through in 1943. 100% losses over 6 months is not insubstantial. If we can keep daylight raid losses within bounds, which I think is possible, we'll be no worse off even if we half the size of 3 Group's initial operational strength. Yes, but even the Wright Field Spits also had 43 gallon tanks behind the pilot, against 33 gallons in the wings (according to the A&AEE report summary on MK210 in S&M). Wing tanks have always been a given with me, as you & Guy have already specified Mk VIII airframes, which had 25 gall leading-edge tanks, but as Quill states, the only available space for major increases in internal fuel was behind the pilot. 43 of _whose_ gallons? I thought Imperial - were the 62.5 gallon Mustang underwing tanks used in that trial US or Imperial? They look bigger than 44/45 gallon RAF tanks. It's worth pointing out that the Wright Field modded aircraft used a somewhat smaller tank behind the cockpit, adn stucl 150 U.S. Gallons of fuel under the wings, where CG wasn't an issue. I'll admit to being a bit puzzled about why the RAF never went for wing rack mounted drops on a Spit, until it occurred to me that there isn't any significant amount of fuel in the wing, and teh plumbing and pumping is going to be a royal pain. I think some of this was dealt with with the Vc, in terms of structure and stressing for under-wing stores. I think 44 gallon ferry tanks should be a possibility. Well, the elevator balance change will add to the stabilizer/elevator combination area, and that's good. It also will reduce the control forces for pitch, possibly to the point whre the controls are over-balanced, and once you start waving the stick around, it wants to amplify the action, and that's bad, leading to overcontrolling at beast, and breaking the airplane at worst, especially with an airplane that's already pretty light on the controls, like a Spit. The bobweight tends to resist this overbalancing, at a cost in stick forces. The thing is, the amount of influence from the bobweight changes, like the elevator balance, with deflection. Absolutely. Over-tightening in turns was an issue, and this could only be evaded, not resolved, in a regime putting more weight behind the CoG datum. It's confusing, adn there's no intuitive answer other than make the tail bigger. The same applies to the rudder, as well. I'm going to give you those in new-production Mk VIIIs and IXs as a priority. I took that as granted for the LR VIII with a 75 gallon rear-fuselage tank. For the LR Vc, we don't need as much in a rear tank, and we only need it for 3 months or so as a proof of concept demonstrator before doing it for real with the LR VIII. Granted. But none of this works without the hierarchy breathing fire from the CAS on down for long-range escorts a la Arnold. Let me know what you think could be done with a range of figures, from 4 inches rearward travel on up, which seems a reasonable conjectural starting point for me. Don't forget to use the Vc airframe as a reference rather than a Vb in regard to landing gear. I'll get round to it, after... Demotion may follow as a consequence of disobeying my petty whims. Now, about those performance figures for Sabre-engined Lancasters.... [beer] After the Great Blaster Worm and Sobig Hydra chases I've had this week, that's top priority. (Work real job, than travel up to the North COuntry to help out some former clients) No beer for bad AMRD's. Just explain the priorities to your clients would you, there's a good chap? Gavin Bailey -- Another user rings. "I need more space" he says. "Well, why not move to Texas?", I ask. - The ******* Operator From Hell |
Thread Tools | |
Display Modes | |
|
|