The 140 high altitude Mk.VII were delivered between 9/42 and 5/44.
The 1,654 Mk.VIII were delivered between 11/42 and 12/44.
Mk.IX production continued until 6/45 and the last Mk.XVI was delivered at the beginning of Aug 1945.
Ad: This forum contains affiliate links to products on Amazon and eBay. More information in Terms and rules
The 140 high altitude Mk.VII were delivered between 9/42 and 5/44.I'm also curious when the Mk.VII/VIII ended compared to the Mk. IX?
No. Compared to P-51D and FW 190 the 'draggiest' features of Spitfire were underwing coolant scoop/cooling drag with windshield & 20mm cannon which were significant - but much less than the wing/fuselage in total parasite drag.From what I remember the draggiest part of the Spitfire was the canopy frame early on because it wasn't highly inclined and had a piece of bulletproof glass on the outside of the frame (the aircraft wasn't designed with bulletproof glass initially, nor was the Me 109): While the last item may/may not have been changed to a cleaner design, I don't know if they ever changed the canopy angle.
I do remember they had a rear-view mirror attached outside the canopy which wasn't terribly conducive to aerodynamic cleanliness, but it probably saved quite a lot of pilots from getting shot down.
A poster here (cant remember who) said that during his studies in college he found the first thing on the Spitfire to "shock" was the front of the canopy but as I understand it that doesnt mean it is most significant at lower speeds, and in any case it is quite important to see out of it..No. Compared to P-51D and FW 190 the 'draggiest' features of Spitfire were underwing coolant scoop/cooling drag with windshield & 20mm cannon which were significant - but much less than the wing/fuselage in total parasite drag.
For ALL aircraft, the draggiest features are a.) the wing, b.) the fuselage/empennage
I've seen that picture before, but I thought that was more like a photo-shoot. That might sound stupid, admittedly.
Okay, so the redesigned cockpit and aft-fuselage cutback coincided with the redesigned tailfin? As for the late Mk. IX tail design, when did that take place?
I'm also curious when the Mk.VII/VIII ended compared to the Mk. IX?
Honestly, it's kind of amazing that we didn't use the 4 x 20mm arrangement.
From what I remember the draggiest part of the Spitfire was the canopy frame early on because it wasn't highly inclined and had a piece of bulletproof glass on the outside of the frame (the aircraft wasn't designed with bulletproof glass initially, nor was the Me 109): While the last item may/may not have been changed to a cleaner design, I don't know if they ever changed the canopy angle.
I do remember they had a rear-view mirror attached outside the canopy which wasn't terribly conducive to aerodynamic cleanliness, but it probably saved quite a lot of pilots from getting shot down.
A poster here (cant remember who) said that during his studies in college he found the first thing on the Spitfire to "shock" was the front of the canopy but as I understand it that doesnt mean it is most significant at lower speeds, and in any case it is quite important to see out of it..
David Lednicer - published a AIAA paper re: Drag Comparisons between P-51B/D, Spit IX and FW 190 - which highlighted the stagnation pressure point at the base of the P-51B and Spitfire IX - and later in a post commenting on the dive tests that resulted in writing off a Spit airframe, that he 'bet' that the first transonic shockwave occurred on the windshield.
I uploaded his paper(s) at least 10 years ago to the Technical Section here.
Thanks Tomo, I read that (to the limit that I can follow it) when posted, but I did read in a post here someone who studied aerodynamics saying he was surprised that that the front of the canopy was the fist to "shock".This should be the doc: link
Dean's figures are correct depending on configuration so "combat weight" would vary. According to the US Navy an F6F-5 with dual bomb racks and rocket launchers weighed in at 12,640 lbs and this would be the normal configuration for the aircraft by 1945:Gross combat weight (i.e. full amount of internal fuel and ammunition but no external load):
13,582 lbs = P-47D (up to -25)
14,411 lbs = P-47D (-25 and up)
12,213 lbs = F6F-3 (-1,369 lbs / -2,198 lbs)
12,483 lbs = F6F-5 (-1,099 lbs / -1,928 lbs)
12,289 lbs = F4U-1D (-1,293 lbs / -2,122 lbs)
12,281 lbs = F4U-4 (-1,301 lbs / -2,130 lbs)
The P-47D was from about 1,100 lbs to over 2,000 lbs heavier than the Hellcat and Corsair.
(Figures from America's Hundred Thousand by Francis Dean, p.122)
Dean did not seem to have all the Manufacturer Specifications to draw from. His data in my experience has always been close - but in the example of P-51s/A-36/NA-73 etc I drew from the NAA specification Reports to build my tables and identify loading from Empty to Basic to Full (Combat) load of fuel, ammo and guns to help clarify the discussion. When I cite Combat loads I mean max Internal fuel/ammo/oil/200 pound pilot/chute, wing racks.Dean's figures are correct depending on configuration so "combat weight" would vary. According to the US Navy an F6F-5 with dual bomb racks and rocket launchers weighed in at 12,640 lbs and this would be the normal configuration for the aircraft by 1945:
Dean's weight for the F6F-3 is for one of the early production versions. According to Grumman by May 1944 the F6F-3 was weighing above 12,400 lbs:
The combat weight of the F4U-1D would vary in the same manner. The US Navy had gross weight with two capped pylons at 12,175 lbs, while Chance-Vought put the weight of a "clean" aircraft at 12,086 lbs:
I'm quite sure that the P-47D varied in combat weight too, sometimes more, sometimes less, depending on configuration. For example, I've read that on occasion six guns were used instead of eight, which is just one example of how this could occur. I didn't want to get nit-picky about "combat weight" but only show how it wasn't always an exact figure as some would make it out to be so generalizations are often used for comparison purposes.
I trust your knowledge of the P-51 family of aircraft above all others and would expect you to source manufacturer documents whenever possible. The point I was trying to make earlier was that even though it was a very heavy fighter the P-47D's performance slowly improved through steady increases in horsepower. This kept it reasonably fast and agile at lower altitudes throughout the war, even before the turbo-supercharger would kick in.Dean did not seem to have all the Manufacturer Specifications to draw from. His data in my experience has always been close - but in the example of P-51s/A-36/NA-73 etc I drew from the NAA specification Reports to build my tables and identify loading from Empty to Basic to Full (Combat) load of fuel, ammo and guns to help clarify the discussion. When I cite Combat loads I mean max Internal fuel/ammo/oil/200 pound pilot/chute, wing racks.
Why did the IX continue after the VII/VIII?The 140 high altitude Mk.VII were delivered between 9/42 and 5/44.
The 1,654 Mk.VIII were delivered between 11/42 and 12/44.
Mk.IX production continued until 6/45 and the last Mk.XVI was delivered at the beginning of Aug 1945.
Okay, I gotcha. It looks like the Mk.IX (and possibly the Mk.VII/VIII) had a different windscreen with the bulletproof pane inside the frame instead of outside.No. Compared to P-51D and FW 190 the 'draggiest' features of Spitfire were underwing coolant scoop/cooling drag with windshield & 20mm cannon which were significant...
I'm curious what advantages the Mk.IX had over the Mk.VII/VIII off the bat? The Mk.VII/VIII had fuel-tanks in the wing from the outset (I'm not sure how many IX's had them)Not too sure about exact dates, but the first Mk. IXs were simply Mk. V airframes, some perhaps retrofitted and many of them new Mk.Vs either on or just coming off the production line, modified and fitted with the 2-stage Merlin 60-series engines, usually a Merlin 61 or 66. Later ... not exactly sure when ... new-production Mk. IXs had the enlarged fin and rudder and recontoured stab and elevators fitted on the assembly line. They are called "late Mk. IXs."
What happened in Darwin?Spitfires were indeed excellent interceptors but they were pressed into service where their range was a severe limitation - including in the role of interceptor (see Darwin).
While I know that ADC/TAC and part of SAC became ACC in the United States in 1992, I didn't know there was an ACC entity in either the USAAF/RAF during WWII. Regardless, I gotta say that the decision made was quite foolish, but not an uncommon rationale: "They're making us look bad, so we're edging them out the way so we can get all the glory".Mustang Mk.I aircraft of the RAF ACC Squadron had been conducting escort operations for the light-medium bombers of No.2 Group RAF since September 1942 and continued to do so until around February 1943. The post action reports from the 2 Group bomber units were generally complimentary about the escort they received from the Mustang Squadrons as they usually actually made the rendezvous with the bombers on time and at the correct place, they stayed with the bombers at the same low level approach and attack altitudes and similar airspeeds, rejoined with the bombers after the bomb run and then stayed with them on the flight back. The same reports contained criticism of the escort being given in a number of instances by the fighter squadrons of FC flying Spitfires, Hurricanes or Typhoons who had either not made the RV, arrived late to the RV, or left the escort role early due to fuel concerns. Criticism from the bomber units also included failure of the FC Squadrons to arrive at the post bombing RV leaving the target area and leaving the bombers early on the return flight due to fuel shortages. The criticism of course did not go down well with HQ FC and as a result, the ACC Mustang Squadrons were no longer invited to partake of that role - separation between Command structures where ACC operations were flown under operational control of FC, convoluted RAF wartime politics and command structures.
Why did the IX continue after the VII/VIII?
Okay, I gotcha. It looks like the Mk.IX (and possibly the Mk.VII/VIII) had a different windscreen with the bulletproof pane inside the frame instead of outside.
I'm curious what advantages the Mk.IX had over the Mk.VII/VIII off the bat? The Mk.VII/VIII had fuel-tanks in the wing from the outset (I'm not sure how many IX's had them)
What happened in Darwin?
Putting the BP glass outside cost a couple of MPH, I think because it changed the airflow around the canopy, but the front of the windscreen was draggy anyway because of its steep angle and shape.Okay, I gotcha. It looks like the Mk.IX (and possibly the Mk.VII/VIII) had a different windscreen with the bulletproof pane inside the frame instead of outside.
It was usually figured to be about 6mph for the external BP glass.Putting the BP glass outside cost a couple of MPH, I think because it changed the airflow around the canopy, but the front of the windscreen was draggy anyway because of its steep angle and shape.
Okay, that makes sense. I assume the Mk.XIV/XVIII had the redesigned elevator eh?Perhaps because the facilities making the VIII converted to the XIV/XVIII?
Understood. I assume the canopy angle wasn't ever changed to give more incline?Windscreen armour was moved from the outside to the inside at some point during Mk V production.
How many of the Mk.IX's have the 13/13.5 gallon tanks in the wings? A flight-manual I found seemed to indicate none...None, in terms of performance.
In production terms, there were fewer things to be changed.
I'm pretty sure that's likely the case. As for the range, what happened with that?Or he could be referring to the Japanese attacks on Darwin which Spitfire Vs, with high altitude Merlin 46s, opposed.
Why did the IX continue after the VII/VIII?
Okay, I gotcha. It looks like the Mk.IX (and possibly the Mk.VII/VIII) had a different windscreen with the bulletproof pane inside the frame instead of outside.
I'm curious what advantages the Mk.IX had over the Mk.VII/VIII off the bat? The Mk.VII/VIII had fuel-tanks in the wing from the outset (I'm not sure how many IX's had them)
What happened in Darwin?
While I know that ADC/TAC and part of SAC became ACC in the United States in 1992, I didn't know there was an ACC entity in either the USAAF/RAF during WWII. Regardless, I gotta say that the decision made was quite foolish, but not an uncommon rationale: "They're making us look bad, so we're edging them out the way so we can get all the glory".
For ALL aircraft, the draggiest features are a.) the wing, b.) the fuselage/empennage
The MkIII from 1940 addressed the drag issue with a retractable tailwheel, enclosed undercarriage, internal bullet proof screen, aerodynamic fairing over the rear view mirror and 3' removed from the wings, the MkIII Seafire had the inner cannon stubs removed, the cannon bulges reduced in size and streamlined and individual fish tail ejectors fitted. What the Spitfire needed was the windscreen sloped back another 10 degree's and a boundary layer splitter fitted to the radiator intakes and she would have been fine.I am not sure improved aerodynamics / reduced drag would negatively affect Spitfire performance any. An extra 30 miles per hour of range + 10 -20 mph of speed seems like it would be an overall
Far as I know the Mk.V's already had the internal bulletproof glass pane, so that wasn't an issue. The IX did have a non-retractible tailwheel, however. I'm amazed they never decided to fair that over.Well, the Mk.VII had a pressurized cabin and a retractable tailwheel along with other minor changes and it was heavier, but could actually fight way up high because the pilots weren't hurting and almost hypoxic. The Mk. VIII was basically a Mk. VII without the cabin pressurization. Other than that, I am not really sure about the differences between a MkVIII and a Mk. IX. They had the same engines and propellers. The Mk. VIII retained the retractable tailwheel held over from the Mk. VII, but other differences between the VIII and IX remain a bit unclear to me. The VIII was likely some 5 - 8 mph faster due to the tailwheel not hanging down in the slipstream. On the other hand, if you had external glass AND the retractable tailwheel, maybe it was a wash, speed-wise.
Also known as a surface to air missile...Well, clearly, if they could have made a fighter without wings and a fuselage, it would have been an absolute speed demon with such minimal drag!
I am surprised they didn't put the retractible tailwheel into the Mk.V production. As for the boundary layer splitter, I'm not sure why that was never attempted.The MkIII from 1940 addressed the drag issue with a retractable tailwheel, enclosed undercarriage, internal bullet proof screen, aerodynamic fairing over the rear view mirror and 3' removed from the wings, the MkIII Seafire had the inner cannon stubs removed, the cannon bulges reduced in size and streamlined and individual fish tail ejectors fitted. What the Spitfire needed was the windscreen sloped back another 10 degree's and a boundary layer splitter fitted to the radiator intakes and she would have been fine.