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We have performance figures for Spitfires carrying about 650lbs of guns and ammo in the wings. DO we have performance figures for the "gun boats"? not just speed but climb? and climb at various altitudes. Service ceiling (climb at 100ft/min), operational ceiling (climb at 500ft/min), do we know what the wing guns did to the roll response (peak/max roll rate could very well be the same)? Did they do much to the turning circle?
109 fans point out that few Spitfires carried four 20 guns even though the wing was laid out for them due to performance problems. The four 20mm set up (for guns and ammo alone) weighs 249 lbs more than the two 20mm and four .303 setup. Two 20mm/151s with 135rpg weigh 316lbs. Without the mounts, gondolas, ammo drum/box, firing controls and any provision for heating. The Spitfire may not have been able to heat the outer 20mms properly but when making that 249lb 'adjustment' on the Spitfire there is no provision for the mounts, ammo boxes, controls and heaters, either for the 20mms going in or the .303s coming out.
Somehow the addition of the underwing guns on the 109 is supposed to have a negligible impact on performance (all performance, not just speed)?Maybe it is just tall tales but why did the Germans continue to fly large numbers of one cannon 109s?
Stories (that may not be true) say that one cannon 109s were "supposed to" engage enemy fighters while gun boats went for the bombers. Like many stories (like Spitfires attacking fighters while Hurricanes attacked bombers) or perhaps theories is a better word, actually combat was more complicated and less easily 'partitioned' than that.
If we assume that there is even a part truth to this the question is why? Couldn't the 'gunboats' take care of themselves in a dogfight?
My actual thesis is that the Spitfire could add more weight without suffering as much degradation in flying qualities or performance (all performance, not just straight line speed) due to the larger wing.
Lets look at that volume to put guns in again shall we. For the original machine guns the Spitfire carried one gun just outboard of the wheels, just about were everybody else put wing guns. the next gun was just inboard of the ailerons, about 2 feet away. The 3rd gun was next to the second but forward of the aileron while the 4th gun was another 2 ft further out, about in the middle of the aileron. This spacing may have been forced by the thinness of wing or a desire not to cross belts over the tops of guns or not to stagger the guns too far back into the wing. We do know that the ammo was contained in demountable boxes. Open the door in the bottom of the wing, drop empty (or part empty) box and insert new full box for quick re-arm ( yes, belts have to pulled from/inserted into the guns). The Spitfire (if I have measured the drawing correctly) has about 2 meters of cord at the point 1/2 the way out the aileron. Does the Bf 109 even have 1 1/2 meters at that point even if we ignore the slats? I will grant that sticking guns and ammo that far out is probably not the best idea if it can be avoided. If the 109 had been required to carry eight MGs from the start it probably would have been quite different.
Strange, I am looking but not seeing the drag numbers. As in a drag co-efficient for the wing or a drag number in pounds for a certain speed. But let's take the 9.5% increase Spitfire MK I has 1030hp and does a bit over 350mph. Cutting the wing 25% should ( in theory) get us to 360.5 mph. (armored wind screen was worth 6mph). Going the other way the small wing plane needs 938 hp to go the same speed. At a cruising speed of 240mph the Spitfire (in theory) needs 352 hp. 10% more is just 35hp. Of course the smaller wing now has a stalling speed 15% higher.
And of course you have the real numbers to back that up? The Spitfire radiators were designed to use the Meredith effect.
How successful they were I don't know but I haven't seen any drag numbers comparing the various versions of the Spitfire, have you?
I see you are not mentioning any increases in drag due to cooling ( water/gylcol and oil) or power requirements of the German engines as their power increased. Was German engineering that good that they could supercharge a 1475hp engine for the same power as an 1100hp engine, Or that they needed no extra power to get 1.8 (or higher) ATA than they needed to get 1.3 ATA?
Or that 1800-2000hp DB605 engine needed no more cooling than the 1475hp BD605 when running at full power?
I read, one chart you supplied had one very questionable entry. quite possibly an honest typographical error. I can find a number of allied "primary documents" that have typographical errors.
There seems to be a difference of opinion on that last part. At least one German pilot saying "Both types are very simple to fly compared to our aircraft, and childishly easy to take off and land"
Both types referring to Hurricane and Spitfire. Both the Spitfire and 109 got worse as time went on. Spitfire had more room to get worse.
Yes, your thesis sounds good if you do not make analysis, but look at above number, they do not lie.
and speed, top, at 7000 m.
G2 5 guns = 650 km/h
VC 4 cann= 579 km/h...
That is all nice thesis, but I am sorry. You say there was more potential in Spitifre to carry more heavy weight, and suffer less penelty. But number show its climb decrease similiar when you add 90% of weight, and at altitude it is still 70 km/h (!!!) slower, and still has less firepower.. just answer my question, look at the above, and which one you would fly, "gunboat" 109G or Spitfire VC with four cannon?
Why is simple to answer. Plane tasked with attacking bombers is busy, it is vulnerable. It needs cover. One gun or three gun version, does not matter. You put it like as this tactic only apply to gunboat, but it applied to any plane tasked attacking bombers, say Spitfire providing top cover to Hurricane. Hurricane was not bad fighter for time, but it could not protect one self when flying straight at enemy bomber. Fighter needs to manuver to protect it self, plane that is locked to straight attack runs cannot do that.
Yes, now please compare speed and power of Jak 3, 109 any version to Spitfire, thank you... Jak 3 with 1200 HP is faster by 40 km/h at SL than Spitfire with 1700 HP.. and turns better, too. Or compare 109G, 1300 HP, to IX Mark, 1300 HP... latter is 30 km/h slower (all ground level, because it simpler, not have to worry about different power ratings at altitude). This should tell you about drag.
So did He 100, Bf 109, Jak 3, Jak 9, MC 202, P-51 etc. Point?
How do you want to figure fuel loads?
The Number of the Chart for the M was 13,275lbs. try sticking just 130gals US in a P-47M and see how far you get
An older P-47 could use 91 gallons of fuel just warming up, takeing off and doing a combat climb to 25,000ft while weighing 12,500lbs. At 14,000lbs it 98 gallons to get to 25,000ft.
Soap operah continues, part 24333!
Of course cool requirement increased on German engine, too. You can see radiator size increase from 109F to G for example. But this was much less extreme then in British case. Reason was that German engine did not rely on supercharging to increase power so much, but also on "free" factor.
Increase piston bore does not cost wasted supercharger power - all fuel burned becomes power at propeller.
Increase compression ratiodoes not cost wasted supercharger power - all fuel burned becomes power at propeller.
Increase scavange time does not cost wasted supercharger power - all fuel burned becomes power at propeller.
It seems to be case (this was discussed other forum). Reason was cooling effect of MW boost, and 1800 hp mw-boosted engine actually radiated less heat than when operating at 1475 HP.
Radiator size was same on 1800 HP and 1475 HP DB 605A(M)
There was no questionable entry. You have been shown real data, now you dismiss it! Okay, I do not agree, but then tell us what was range of 109F, G, K.
Refer to the above, and you will see why I disagree strongly. But basic difference is this, I try to define reasons, quantify analysis, you repeat 'Spitfire had more room to get worse, Spitfire had more room to get worse'. Opinion is okay, but if you do not have more to offer than opinion, ie. some unpartial arguements like mathematics to support, I have to agree to disagree only. As we say - "taste and power of slapping are different from person to person"I do believe however, that so far your thesis is built much more on subjective opinion - taste if you like - than mine.
Jak 3 had version with 3 20mm in nose - and it was only 20 kg heavier than base version. 370 20mm round in total. Spitfire had 240 for two guns..
I do not get idea of weight of gun. Why does it matter? Explain me. Fighter is mostly limited by fitting space, not weight. This is where "big wing" theory is wrong. Actual execution is much more important, than size.
If I weld a big piece of lead to the B20 it makes it more impressive? Or do you think 20 kg differences matters substential to a 3000kg airframe..??
BTW it also shows the error of reasoning. You seem think - hey, look Jak airframe could only carry one 20 mm, one 12,7mm... because of it carried this amount of gun was so small, no room for improvement etc. But then, a later version carried three cannon, a more heavy armament than Spitfire, but with 2/3 wing size.. do you not still see through this examples where you are mistake lay?
It is wrong thinking imho that if something was done, it means more was not possible..
I was looking at FTH, not the cielings.a few points.
Some Spitfires "puttered out" at 43,000-45,000ft depending on engine.
An indication of the planes ability to sustain a turn might be ( i could be wrong) reflected in it's climbing ability at a given altitude. A MK XIV in one test is shown climbing at 1800ft/min at 34,000ft. which is several hundred ft/min better than P-47M.
If you're referring to weight of the armament, i'd disagree. If the armament, such as wing cannons, causes more drag then i would agree.OK, lets, Yak 3 goes 351mph. MK XII Spitfire goes 346mph. Yak has less drag but where is the 40kph? Yak is carrying less armament.
Seen it, both test reveal similar figures for both planes.
Is it about mach, or is it about speed/acceleration?
The P-47 got there in 8000ft (22k ft) and in 12 seconds, albeit also in thicker air, while the Spit took nearly 15,000ft and 40 secondsfrom 40k ft.
We can use other tests that put the mach number for the P-47 above .90...but who's counting.
I think the Spit actually cleared 0.95 in one test (677mph)....1948, diving all the way to deck from above 40,000ft.
You mean a 3 minute google search doesn't reveal that chart?
Man....I got to do all the digging.
The chart was at 22,000ft between SpitIX and P-47D-22.
Different figures may have been revealed at higher altitudes and using later profiles.
At that height, the P-47 outperformed the Spit in sustained turns above XGs, and at XXXmph....
I haven't been able to find the chart, but its there somewhere in cyberspace.
drag and power profile, particularly at altitude, if we're still talking about sustained turns.
There's also a saw tooth to the power chart because of the supercharger stages, which despite aircraft having "pretty much" the same engines
they can end up performing quite differently at different heights.
Drag has 2 elements. Induced drag is lower on Spitfire because low wingload. Parasite drag is very high for same reason compared to any other, probably greatest of any comparing WW2 fighter.
You make it look like as turn would be only about induced drag, but sorry, this is wrong. It is also about parasite drag.
Second. Drag is only one part of formula of turn. You are miss half of story, sorry... Sustained G hold capacity is dependent on which G load can fighter drag = fighter thrust.
You missed thrust complete. Thrust is very important. If you have more thrust, you can have more drag.
For this reason, your statement is not true. Both Soviet Jak 9 and Jak 3 fighters could hold higher sustained G than Spitfire.
Yes, now please compare speed and power of Jak 3, 109 any version to Spitfire, thank you... Jak 3 with 1200 HP is faster by 40 km/h at SL than Spitfire with 1700 HP.. and turns better, too. Or compare 109G, 1300 HP, to IX Mark, 1300 HP... latter is 30 km/h slower (all ground level, because it simpler, not have to worry about different power ratings at altitude). This should tell you about drag.
RR practice was to put in only a more powerfuel supercharger, give supercharger more horsepower from engine to drive it. All that horsepower given to supercharger consumed fuel, but added directly no
Jak 3 had version with 3 20mm in nose - and it was only 20 kg heavier than base version. 370 20mm round in total. Spitfire had 240 for two guns..
I've never seen "similar" dive limits for the P-47. It had relatively thick wings which meant it entered compressibility at lower speeds. There's no getting away from that.
It's not important at lower altitudes, but at high altitude it is a major limitation.
Why do you think that is?The P-47 was diving at a steeper angle. (and that's not say the Spitfire couldn't, just that the RAE had a standard test procedure)
(there is no special code or formula here)It's about both. It's no good being able to accelerate quickly if you lose control.
It doesn't appear that made much difference.Note also the instructions in the P-47 manual not to enter a dive at full throttle because you have to throttle up during the dive to prevent the nose dropping further. That's going to limit acceleration, too.
Altitude and speed are advantages, you trade one for the other, and the plane that gains more speed for less altitude will not only gain separation, but would save a height advantage.Originally Posted by Shortround6
The P-47 could accelerate better in a dive, no question, and that is a very practical thing. A plane that accelerates quicker in a dive and use the increased separation to break contact before the slower accelerating ,but ultimately fast plane can catch up.
The problems with comparisons usually come down to altitude.But I'd question the Yak's superiority over the Spitfire at any altitude. Against a clipped wing IX at 18lbs boost, perhaps, but a full span IX at 25 lbs boost?
I was looking at FTH, not the cielings.
I'm unaware of any Spit or Mustang with an FTH above 30k ft, which is usually why the Spit gains in climb from being a lighter air frame (above FTH).
As i understood it, climb is usually a reflection of weight. You can see this with same model aircraft retaining top speed ability, but a more noticeable difference in climb rate because of load.
If you're referring to weight of the armament, i'd disagree. If the armament, such as wing cannons, causes more drag then i would agree.
Underwing cannons, pylons, etc. They all add drag to slow the plane down.
That 40kph could mean the Yak is just a faster plane, period.
Need I mention, the Spit needs to dive to hold the same speed as the P-47 in level flight at 40,000ft.
Are you still convinced the Spit was ideal for high altitude support?
good point.As always, which Spitfire, which P-47 and when.
Another question is by how much. if the difference is 15-20mph out of 390mph it may not make a lot of difference even if technical correct. At this point there may be as much difference from one airplane to another as their is between different types of airplane. One test of a P-47D in Oct 1943 shows a rate of climb at 38,000ft at 500ft/min. an early 1944 test of a MK IX HF shows rates of climb at 36,000ft of 1270ft/min and 40,000ft of 610ft/min. Spit may be slower but it climbs a lot better. Must be out of putter though
Another question is by how much. if the difference is 15-20mph out of 390mph it may not make a lot of difference even if technical correct.