Enzo the Magnificent Posted October 15, 2012 Posted October 15, 2012 In 1937, Rolls-Royce developed the Vulture aero engine. It was an ambitious concept and was effectively two Kestrel engines joined to a single camshaft. Rolls-Royce had considerable experience with V12 engines and their Merlin engine was proving to be very reliable. However, many people were not convinced of the manufacturer's ability to meld two V12 engines into an X24 configuration and so an enlarged Merlin, the Griffon, was put into the preliminary design stage. In the event, the Vulture engine proved to be every bit as reliable as the Merlin. The Vulture was used in the new Avro Manchester bomber which became an instant success being fast, capable of reaching high altitudes and able to carry a prodigious bomb load. Avro had not been convinced of Rolls' ability to deliver the vulture and had started to design an alternative - a weird mutant Manchester with four Merlin engines. No one really liked the concept. With the success of the Vulture and the Manchester, Avro breathed a sign of relief and abandoned development of their ludicrous flight of fancy. Likewise, Rolls abandoned the Griffon, which was only ever seen as a stopgap. In 1939, NE Rowe of the Air Ministry suggested fitting the Vulture into a Spitfire. It was clear that the Spitfire would eventually need a more powerful engine to enable it to counter the increasing performance of German fighters - especially the Heinkel He 100 which was just starting to enter service in large numbers. Although preliminary design work was carried out on the Vulture Spitfire, it was decided that the Vulture should be kept for the Manchester bomber force. An alternative was the Napier Sabre engine, which was already proving to have a great potential in the Hawker Typhoon. The first Sabre powered Spitfire, DP845, was designated the MkIv and flew in late 1941. Some major airframe redesign was required. The Sabre engine was much wider and taller than the Merlin it replaced, but was not as long. In order to exploit the extreme power of the Sabre, a large diameter airscrew was designed but it was found that this would strike the ground if the Sabre's thrustline was set at the same height as that of the Merlin. Therefore the Sabre was set at a higher level, meaning that the fuselage had to be made deeper. The cockpit was therefore higher but, combined with the shorter nose, this meant that the pilot had a better field of view. The cockpit was provided with a bubble canopy, further improving the pilot's view. The next problem to be addressed was that of cooling the engine. The Spitfire radiator was simply not up to the task. Consideration was given to having a twin-radiator configuration as used in the proposed twin-stage Merlin versions, but even this would not have provided the cooling capability required. In the end it was realised that Hawker had already solved the problem in the Typhoon and so Lord Beaverbrook arranged for Hawker to transfer their engine mounting drawings to Supermarine. In the end, the nose of the Sabre Spitfire was almost identical to that of the Typhoon. Placing the radiator in the nose of the aircraft freed up space in the wings which were used for fuel tanks, thus solving the worst of the problems of the Spitfire - short range. A further installation of fuel tanks underneath the cockpit in the deeper fuselage gave the Sabre Spitfire a prodigious range. The first Sabre Sptifire, the Mk XII, entered service in August 1942 with 41 Sqn. The aircraft was phenomenally fast, being capable of 460 mph at 25,000 ft - far faster than anything else in European skies. An additional benefit of the nose mounted radiator was that the effective wing surface was now greater and so the Spitfire XII was equally as manoeuvrable as the early Spitfire I. However, the large side area of the nose led to a quite severe lateral instability. Although manoeuvrable, the Spitfire Mk XII was very tricky to fly - particularly when landing in even the mildest crosswind. The extreme power of the Sabre engine - by this time in excess of 3000 hp, meant that the aircraft swung horrifically as soon as the tailwheel lifted on take off. It seemed to the aircraft's pilots that the Spitfire XII simply didn't like being anywhere near the airfield, and as soon as it was in close proximity to the airfield it would try to punish the pilot. The Mk XII was not well liked by its crews. Various fixes for the instability problem were tried, involving broad chord rudders and larger fins, but none were successful in eliminating the problem. Supermarine therefore decided to redesign the Sabre Spitfire. The design office introduced a completely new tail section with a huge sail-like fin and rudder together with larger tailplanes. This eliminated the instability problem totally. The opportunity was taken to redesign the wings as well. The new wing retained the elliptical plan but had a new laminar flow aerofoil shape. The wing was also stiffer and had a different armament configurations. Gone were the outboard machine guns. There was now a single gun bay in each wing, fitted with twin 20mm Hispano cannons as standard. With the instability problems solved, the redesigned Sabre Spitfire became a very pleasant aircraft to fly and retained the speed, range and manoeuvrability of its predecessor. The design changes meant that no one really considered the aircraft to still be a Spitfire, so a new name was chosen, the Supermarine Victor. Oddly enough, the mark numbers were carried on from the Spitfire line and so the first service version of the Victor was the MkXIV. The first Victors entered service in June 1943, again with 41 Sqn. The Luftwaffe had been engaged in hit and run raids across the Channel with strikes by He100s and Ta152s at low altitude. The Spitfire XIIs had had some success in countering these raids but were not available in the numbers that were needed. The Victor replaced the Spitfire XII in the interceptor role in very short order. Victor pilots exploited the very high speed and long range of their aircraft by making their interception way out over the Channel - and in some cases over France. Due to the long endurance of the Victors, they would fly standing patrols over the Channel in an attempt to goad the German fighters into a confrontation. This challenge was rarely taken up. However, as the accuracy of British RDF improved, it was soon possible to pick up German raiders as they took off. The Victor patrols operated under a "cab rank" principle and two aircraft would be designated to engage the tip and run raiders as they formed up just after take-off. By November 1943 the Victor squadrons could gain air superiority over any location on the continent at the drop of a hat. This led to a change in tactics by Bomber Command. It seemed pointless to carry on the night bombing campaign when day bombers could be escorted to and from their targets by Victors. So, the Manchesters became day bombers in early 1944 and commenced precision strikes on German industry. By the time that the US entered the war in June 1944, the Commonwealth forces had established a beach head at Dieppe and Victors were operating from the continent. The war didn't last much longer. 2
Procopius Posted October 15, 2012 Posted October 15, 2012 Love the backstory. I'm really excited to see this one take shape.
Fifer54 Posted October 15, 2012 Posted October 15, 2012 Great backstory! Can't wait to see the model . . . My first thought on your backstory was "there's a great big hole in this!" which was, if the RR Vulture had worked "out of the box", wouldn't Napier's Sabre have been cancelled? It did have it's own set of problems, and a "working" Vulture would have meant that Hawker developed the Tornado to production, probably instead of the Typhoon with it's troublesome Sabre. But then, the world of your backstory is your world, and if the RR Vulture worked OOB, why shouldn't the Napier Sabre?! I've already spotted the hole in my backstory, I'm just hoping no-one else does . . .
Enzo the Magnificent Posted October 15, 2012 Author Posted October 15, 2012 if the RR Vulture had worked "out of the box", wouldn't Napier's Sabre have been cancelled? It did have it's own set of problems, and a "working" Vulture would have meant that Hawker developed the Tornado to production, probably instead of the Typhoon with it's troublesome Sabre. It's always good to have twin point production, just in case one design turns out to be pants. The RAF had been burned already by the failure of the Peregrine and they decided that they wanted a range of options. And if both engines are a success, then you have insurance in case one factory gets bombed. As it stood, the Vulture was deemed better for use in bombers and so the Manchester got first dibs - only fair as it was already in service with that engine while the Tornado was still a prototype. Anyroads... here is what I will be using for this build. Basically a load of spare bits... Wings from an Airfix Spitfire Mk24, modified back to the classic planform using tips from an Airfix Seafire 17. Fusealge from the Aeroclub Spitfire XII conversion kit, rendered redundant by the Airfix kit. The tail will be from the Airfix Spitfire 24 - but a different kit from the wings. I have lots of Mk24 bits lying around. The remainder of that fuselage will be used to covert a Hasegawa IX into an FR.XIV. Given the promise of a new accurate IX from Eduard, it seems that all the Hasegawa IXs in The Stash will now be converted to Griffon Spits. A pure flight of fancy, because as we all know the Griffon was cancelled before it got off the drawing board. The engine is from the Eduard Tempest. I cut this off when I built a Tempest II for the Close Air Support GB. I couldn't bear to get rid of the offcuts, which is what led to this Whif. The wheels are from the Alley Cat Tempest correction set. And there will be all sorts of other scrap bits involved, as and when I decide to use them. I reserve the right to bung anything in there that I want!
General Jumbo Posted October 15, 2012 Posted October 15, 2012 Great story - I'm looking forward to this...
Col. Posted October 16, 2012 Posted October 16, 2012 Cracking back-story Enzo, welcome to the GB, can't wait to see how this one looks.
beastieboy Posted October 16, 2012 Posted October 16, 2012 This should be good, will follow with interest
Arniec Posted October 16, 2012 Posted October 16, 2012 Love the story and I am watching this one with interest.
Enzo the Magnificent Posted October 21, 2012 Author Posted October 21, 2012 Not much movement on this one. I'm concentrating on getting my Starfighters sorted by the end of the GB. However, I did saw off the tips of the Mk24 wings. I had always been under the impression that the wing planform of the later Spitfires was totally different to the classic elliptical shape. . But it turns out that it is identical. It is just the shape of the wingtips which is different. If you saw the wingtips off a Mk24 wing, the original tips fit perfectly. What is different is that the later wingtips are an integral part of the wing. The ailerons extend into the wingtips, unlike on earlier wings, but that shouldn't make much difference to the model. I have also sawn the fuselage and tail bits off. Here is what the fuselage should look like. At the moment it looks suspiciously like a Merlin Spitfire with a Vokes fiter, but I'm hoping that the raised cockpit and large fin and rudder will make it look somewhat different.
TaiidanTomcat Posted October 21, 2012 Posted October 21, 2012 You are not playing around are you? Nice cuts!
Col. Posted October 21, 2012 Posted October 21, 2012 I know they are only laid together but that engine cowl looks as if it was made for the job and will be a good fit. Your work on the wing also comes under the 'you learn something new every day' heading. Said I was looking forward to seeing this one take shape and I'm not disappointed
Enzo the Magnificent Posted October 28, 2012 Author Posted October 28, 2012 Slow progress on this one. Basically I've wreaked a little more destruction.
TaiidanTomcat Posted October 28, 2012 Posted October 28, 2012 Cutting is the best part... putting it together and sanding less so LOL
gingerbob Posted October 29, 2012 Posted October 29, 2012 I had always been under the impression that the wing planform of the later Spitfires was totally different to the classic elliptical shape. . But it turns out that it is identical. It is just the shape of the wingtips which is different. What is different is that the later wingtips are an integral part of the wing. The ailerons extend into the wingtips... Right you are. The Mk.21 wing initially used the extended tip, which allowed the aileron to grow (though they had to "crank" the rear spar to do this). Then they clipped it back to about the same span as the "classic" Spit. Not sure I want to see what this is going to end up looking like, but I can't stop watching... bob 1
Enzo the Magnificent Posted October 29, 2012 Author Posted October 29, 2012 Not sure I want to see what this is going to end up looking like It's a Spitfire, Jim, but not as we know it...
Enzo the Magnificent Posted November 3, 2012 Author Posted November 3, 2012 Still slow going on this one. I have raised the cockpit. It looks like a total dog's breakfast at the moment, but bear with me... It will look better soon. At least, that's the plan! The fuselage sides have been reinforced by using the cockpit walls from an Eduard Tempest and huge wodges of milliput!
Col. Posted November 4, 2012 Posted November 4, 2012 Taking an ever more radical shape there Enzo! Can't help thinking there's something of the Sea Fury creeping into the lines of this one so far.
Enzo the Magnificent Posted November 4, 2012 Author Posted November 4, 2012 Taking an ever more radical shape there Enzo! Can't help thinking there's something of the Sea Fury creeping into the lines of this one so far. Indeed. Just be aware that the step in front of the cockpit will disappear when the engine is on. Interesting comment about the Sea Fury. At first I intended to raise the cockpit and move it forward so it would end up looking a bit like the Firebrand.
Enzo the Magnificent Posted November 11, 2012 Author Posted November 11, 2012 The cockpit parts painted and ready for installation And installed...
ChancerUK Posted November 11, 2012 Posted November 11, 2012 This is shaping up into a pretty fascinating build. Great believable base concept. Will the end model have any kill credits on it?
Enzo the Magnificent Posted November 11, 2012 Author Posted November 11, 2012 Will the end model have any kill credits on it? Hmmm... I hadn't given that any thought. But it's a good idea.
Enzo the Magnificent Posted November 14, 2012 Author Posted November 14, 2012 Time to break out the Milliput! The Tempest nose is considerably wider than the Spitfire fuselage, so I used Milliput as an adhesive to bridge the gap between the two sections. I also rolled a tube of Milliput to reinforce the join between the tail and the fuselage. I have extended the nose slightly. I want to use the Spitfire 24 five-bladed spinner with Tempest blades. The Spitfire spinner is much narrower than the Tempest one hence the extended nose. Hopefully it should serve to make the nose a little more shark-like. The wing assembly needed a section cut out to allow it to fit around the Tempest radiator. Finally, here is the wing test fitted to the fuselage. I'm going to need a lot more Milliput to fair everything in nicely...
mike romeo Posted November 14, 2012 Posted November 14, 2012 Weird! Yet somehow believable . . . regards, Martin
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