Was the corsair as good a fighter as the spitfire or the FW?
- Thread starter Soundbreaker Welch?
- Start date
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Yes there are figures. Soviet data says "gunboat" (I do not really like term. It suggest two different version of plane, when its one. 109 that mechanic installed gondola, and 109 that mechanic did not installed gondola.)
Gunboat (five point G-2) is 10-15 km/h slower, climbs 2m/sec slower. Service ceiling (Soviet definition) 11250 m against 11 900 meter.
Difference between two types is five pointer is 3235 vs 3023 kg, or 212 kg difference if gondola is mounted to plane.
Now, to supply your thesis, please provide effect of adding cannon to Spitfire. I find this. Two Spitfire V, equal setting. One VB with 2x20mm + 4 x 7,7. Other VC 4x20mm. Spitfire Mk VB W.3134 Report Spitfire Mk.Vc AA.873 Report.
Note VC is bit more power in test than VB (9,3 lbs vs 9,1 lbs "boost")
VB 2960 kg, 16,5 m/sec, 11 430 estimate service ceiling,
VC 3140 climbs 14,75 m/sec (-1,75 m/sec), 11 100 estimate service ceiling,
So, comapare effect of weight between G-2/G-2gondola, Spitfire B and C! How heavier version is different, and what are penelties.
Me 109G2
+ 212kg weight, -2 m/sec, -650 m service ceiling.
Spitfire V
+ 180kg weight, -1,75 m/sec,-330 m service ceiling.
Note Spitfire is gaining only bit less weight, but negative effects are very similiar. Newton was English, but he was not biased hehe
Now, which fighter is more heavily armed?
Spitfire: 40 20mm rounds per sec output. Total 480 20mm rounds available.
109G/5gun: 38 20 mm rounds + 20 7.92mm per sec output. Total 200 + 145 + 145 = 490 20mm rounds + 1000 7.92 mm rounds available.
Also please compare rates of climb, to 5000 m
G2 5 guns = 5.1 min
VC 4 cann= 5.9 min
and speed, top, at 7000 m.
G2 5 guns = 650 km/h
VC 4 cann= 579 km/h...
Yes, your thesis sounds good if you do not make analysis, but look at above number, they do not lie.
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.
Okay - so lets see you data. I provided my data to let you see why I am very strong convinced otherwise. It would be curtous not to argue but instead support your data as well.
The main difference is not as much between the inside volume. It is how the wing is designed. 109 has main spar in the middle, which limits lenght of gun, and slat for half the wing. You can only place gun betwen the wheel well, and the slat. On E modell there was three section of wing in this section, divided by ribs. One section was used to carry MG, or it was used for MG FF drum (needed to be placed sideway of gun so it can eject on other side), MG FF on middle, and third section housed spent casing. Spitfire has no slat, so can use all wing volume outside wheel well, and spar runs in the front. You could probably redesign 109 wing with Spitfire like front spar, but this would sacrifice wing rigidity, and lead to similiar aileron reversal/wing flex trouble as on Spitfire. You could also delete slats and use fences on top of wing (like MiG 15 or Spanish Hispano 109). But you need correct (scale) drawing to look at actuals.
But all this is irrevelent. We know 109 regular flew with 3 cannon and two MG/HMG, Spitfire flew with 2 cannon and four (two H)MG. Comparison on top shows firepower. So what significance discussion on wing carried armament has? Nothing IMHO.
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?
I have seen data suggest about 40 mph speed decrease of Spitfire due to airframe "developments" up to mid war.
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 RPM does not cost wasted supercharger power - all fuel burned becomes power at propeller.
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.
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
Simple example. You have 1200 HP engine. Say it consume 0.3 liter/HP, this case, 360 liter per hour, total. You give 200 HP to supercharger (60 liter), the propeller gets remaining 1000 HP.
That is 1000 (useful) HP for 360 liters, thats 2.7 useful HP / liter fuel carried for an hour.
Now you add a bigger supercharger, you give it another 400 HP during development.
Engine now gives 2400 HP, now supercharger consumes 600 HP, leaves 1800 for propeller.
Consumption is still 0.3 liter/HP. So now supercharger consumed 180 liter per hour, but gives no thrust at all (it just allows engine to burn more fuel),
the remaining power (1800) consumes further 540 liter, total 720 liter per hour.
That is 1800 (useful) HP for 720 liters, or 80% more power for 100% more fuel consumption, that is 2.5 useful HP / liter fuel carried for an hour.
This is RR development in nutshell. They aimed for a decreased dividients in long term.
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.
There are many pilot opinions, trials etc. Some are contradicting. But, I have asked you to define good handling, and you still did not answer. There is generic agreement however in all opinions I have seen the 109 was extremely fogiving in the air. Some manouvers were of course easier (stall warning, coming out of stall, near-stall handling were extreme good for example), others were more difficult (like loop was difficult because poor stability in direction) than other. But it is hard to quantify. For example, stability in traverse axis was very good in 109, very bad in Spitfire. Stick harmony was overall heavy but well balanced and natural on 109, and extreme unbalanced on Spitfire. One was frequent to loop, other was frequent to nose over. How do you quantify this?
So, as I said, you have to define handling. What qualities refer to good handling? Have luck, even national test centres could not agree what is optimum..
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.
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 RPM does not cost wasted supercharger power - all fuel burned becomes power at propeller.
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.
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
Simple example. You have 1200 HP engine. Say it consume 0.3 liter/HP, this case, 360 liter per hour, total. You give 200 HP to supercharger (60 liter), the propeller gets remaining 1000 HP.
That is 1000 (useful) HP for 360 liters, thats 2.7 useful HP / liter fuel carried for an hour.
Now you add a bigger supercharger, you give it another 400 HP during development.
Engine now gives 2400 HP, now supercharger consumes 600 HP, leaves 1800 for propeller.
Consumption is still 0.3 liter/HP. So now supercharger consumed 180 liter per hour, but gives no thrust at all (it just allows engine to burn more fuel),
the remaining power (1800) consumes further 540 liter, total 720 liter per hour.
That is 1800 (useful) HP for 720 liters, or 80% more power for 100% more fuel consumption, that is 2.5 useful HP / liter fuel carried for an hour.
This is RR development in nutshell. They aimed for a decreased dividients in long term.
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.
There are many pilot opinions, trials etc. Some are contradicting. But, I have asked you to define good handling, and you still did not answer. There is generic agreement however in all opinions I have seen the 109 was extremely fogiving in the air. Some manouvers were of course easier (stall warning, coming out of stall, near-stall handling were extreme good for example), others were more difficult (like loop was difficult because poor stability in direction) than other. But it is hard to quantify. For example, stability in traverse axis was very good in 109, very bad in Spitfire. Stick harmony was overall heavy but well balanced and natural on 109, and extreme unbalanced on Spitfire. One was frequent to loop, other was frequent to nose over. How do you quantify this?
So, as I said, you have to define handling. What qualities refer to good handling? Have luck, even national test centres could not agree what is optimum..
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. Shortround6
Lieutenant General
Certain models of the Russian fighters would be lucky to turn at all at much over 30,000ft without loosing altitude. Others could do much better. As always, what was the combat load being carried? The weight of a single 20mm ShVAK with120 rounds and a single 12.7mm UB with 220 rounds was under 260lbs.
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 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..
Hello Tante Ju
Quote: " Yet Jak 3 turns better and is much faster."
No problem with that Jak-3 turned better than Spit at low level but much faster? Much faster than Spit Mk V but when Jak-3 appeared at front, Spit Mk VIII and IX had been there a year ot two, and they had appr same max speed as Jak-3 and Spit Mk XIV was almost exact contemporary with Jak-3 and it was clearly faster than Jak-3
And the 3 cannon Jak-3 production began in Apr 45 IIRC
And the "gunboat" G-2 aka G-2/R6 max speed was 636km/h, if early with semi-retractable tailwheel or apr. 628km/h if late G-2 with fixed tailwheel.
Finns loaded the central gun of 109G with 140 rounds, they were tipped by Germans that with full 200 ammo load the belt breakage was too common and so it was better load only with 140 rounds.
Quote:" 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,"
In fact, see for ex Priens Stemmer's II./JG 3, some Gruppen were in Autumn 43 designed as light Gruppe and they didn't use underwing gungondolas or not even drop tanks and had the duty to protect heavy Gruppen.
Quote:" You could probably redesign 109 wing with Spitfire like front spar, but this would sacrifice wing rigidity, and lead to similiar aileron reversal/wing flex trouble as on Spitfire."
Was there aileron reversal problem with Spit? wing flex yes but still Spit after they got metal ailerons rolled better than 109G at all speeds. But there wasn't so big difference between 410 – 520km/h (255-323mph)IAS between 109G and normal wing Spit Mk V.
Quote:" 109 regular flew with 3 cannon and two MG/HMG"
I'd say that every 109G could take the 2 underwing cannon but they were not normally armed with them and when time passed the underwing canon came progressively more rarer.
Juha
Quote: " Yet Jak 3 turns better and is much faster."
No problem with that Jak-3 turned better than Spit at low level but much faster? Much faster than Spit Mk V but when Jak-3 appeared at front, Spit Mk VIII and IX had been there a year ot two, and they had appr same max speed as Jak-3 and Spit Mk XIV was almost exact contemporary with Jak-3 and it was clearly faster than Jak-3
And the 3 cannon Jak-3 production began in Apr 45 IIRC
And the "gunboat" G-2 aka G-2/R6 max speed was 636km/h, if early with semi-retractable tailwheel or apr. 628km/h if late G-2 with fixed tailwheel.
Finns loaded the central gun of 109G with 140 rounds, they were tipped by Germans that with full 200 ammo load the belt breakage was too common and so it was better load only with 140 rounds.
Quote:" 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,"
In fact, see for ex Priens Stemmer's II./JG 3, some Gruppen were in Autumn 43 designed as light Gruppe and they didn't use underwing gungondolas or not even drop tanks and had the duty to protect heavy Gruppen.
Quote:" You could probably redesign 109 wing with Spitfire like front spar, but this would sacrifice wing rigidity, and lead to similiar aileron reversal/wing flex trouble as on Spitfire."
Was there aileron reversal problem with Spit? wing flex yes but still Spit after they got metal ailerons rolled better than 109G at all speeds. But there wasn't so big difference between 410 – 520km/h (255-323mph)IAS between 109G and normal wing Spit Mk V.
Quote:" 109 regular flew with 3 cannon and two MG/HMG"
I'd say that every 109G could take the 2 underwing cannon but they were not normally armed with them and when time passed the underwing canon came progressively more rarer.
Juha
Shortround6
Lieutenant General
I guess it depends on how much we can bend or twist them before it is a "lie".
Both planes suffer degraded performance. Which is the basic argument or at least mine. The Differences in climb and ceiling make it hard for a unit with mixed aircraft to maintain combat formations. I have told that that there was little difference between a 3 cannon 109 and a 1 cannon 109 and while there is little speed difference the ceiling penalty is somewhat greater. While the speed penalty is just 1.5-2.3% the ceiling difference is 5%, What is the climb penalty and more importantly what is the climb penalty at the higher altitudes?
Service ceiling is usually 100ft/min or 0.5m/s. It is not uncommon for the differences between individual aircraft to mean that they cannot fly in formation with each other at this height so some air forces us an "operational" ceiling at which the planes have to do a nominal (average) 500ft/min climb or 2.5m/s. This should mean that a small group of planes can at least stay in formation. To actually engage in combat and have some hope of staying at the altitude (or near it) that one started at (excluding attacks that just dive through the enemy formation) some air forces had a definition of a "combat ceiling" which was 1000ft/min or 5m/s.
While losing 1.5-2.0 a second off the peak climb rate may not sound like much, loosing 1-1.5m/s in climb can affect the altitude the plane can fight at by hundreds of meters.
Gravity is not biased. Both planes suffer. I just get tired of hearing that 3 cannon 109s had negligible performance penalty.
As far as my thesis goes, the difference in power between the VB and VC was minimal, Under 1%, 0.2lbs out of a total manifold pressure of 24lbs.
The question of armament and aircraft design is not so simple. You want to turn it to which was more effective which is another whole set of arguments. The Spitfire designers could no more pick and chose the types of guns to arm their fighter with than anybody else could. For most of the war it was .303 Brownings or Hispanos. One or the other, how many can you fit in. There was no lighter cannon to pick from.
The Spitfire carried a greater weight of armament than the 109, that is a fact. as I just said, the effectiveness is another argument.
As for the armament you give for the 3 cannon 109, can you give a source please. Most of mine say 150 rounds for the fuselage cannon (200 rounds for the F with the 15mm gun) and 120rpg for the under wing guns. what is 90 rounds between friends?
And lets compare those tops speeds shall we.
Spitfire VC at 7000meters had under 6lbs of boost. Which means it had just over 1000hp. The G2 had what? 1230HP at that height?
Well, in 1941 I would choose the Spitfire. The 109 G doesn't show up until about a full year after the MK V.
I wonder what a four cannon Spitfire would have performed like with a 1942 engine?
Why not use all three cannon fighters for flexibility? Hurricane wasn't "bad" but the British knew it wasn't quite up to snuff against the 109. Using Hurricanes to fight 109s while Spitfires went for bombers would have given worse results.
Look again at the two Spitfire reports. While max ceilings were with in a few hundred feet of each other the operational and combat ceilings where much further apart. At 30,000ft the standard Spitfire could out climb the 4 cannon one by just over 19% instead of the 11% at lower altitudes. If the 3 cannon 109 showed a similar penalty at altitude it could explain a lot.
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.
You just made it. DO you have any idea how successful these different designs were at getting the Meredith effect to work? I don't. I would guess that the P-51 was the most successful with the He 100 the least ( why retract the radiator in flight if it is giving thrust?). Without knowing what parts of the air frames and engine installations contributed what % to total drag it is a little hard to pick just one thing on an airplane and say "this was bad".
one set of figures for the Spitfire (at a very low speed) show that the wing was responsible for 20.3 pounds of profile drag out a total for the plane of of 60.2 pounds for all drag, not just profile. The tail wheel was worth 2 pounds. While making the wing smaller would have reduced the the profile drag even reducing 1/3 of 1/3 of total means that fitting a retracting tail wheel and smooth paint would have made half the difference of the smaller wing.
davparlr
Senior Master Sergeant
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
You have a point there. How about comparing weight at 34,000 ft., getting there is not important, with enough fuel for 5 min WEP and flying 50 miles, approach and landing and reserve. This would be a more realistic comparison.
All done with already burned fuel.
Shortround6
Lieutenant General
Soap operah continues, part 24333!
You got that right.
TANSTAAF
Increase RPM does not cost wasted supercharger power - all fuel burned becomes power at propeller. [/QUOTE]
Wrong. Increase rpm increases internal friction. Friction goes up with the square of the speed. Increasing for 2500 rpm to 2800 rpm increases friction by 25%. Stronger valve springs increase drag on the cams.
Better, 80% of internal friction (rule of thumb) comes from piston to cylinder scrubbing or piston ring friction. Germans increased wall scrub area by 2.6% rather small increase but not FREE.
Increasing compression from 6.9:1 to 8.5:1 increases MEP by about 10% Increasing compression from 6.9:1 to 8.5:1 increases peak cylinder pressure by about 20%. You need heavier construction to hold the strain. All fuel burned may be power to the propeller but it is not FREE power.
OK this sounds good, but the engines that used the increase overlap cams also used a special auxiliary intake system for idling. Extra cost, weight and complication.
Simple example. You have 1300 IHP engine at 2500rpm Say it consume 0.3 liter/HP, this case, 390 liter per hour, total. You give 200 HP to supercharger (60 liter), engine friction is 100hp (30 liters) the propeller gets remaining 1000 HP.
That is 1000 (useful) HP for 390 liters, thats 2.56 useful HP / liter fuel carried for an hour.
Now you increase the rpm to 2800rpm. Engine now gives 1456Ihp still at 0.3 liter/HP
Supercharger still takes 200hp? it won't, it needs to move 12% more air so it is 224hp.
Internal friction is now 125hp.
leaves 1107 for propeller.
Consumption is still 0.3 liter/IHP. or 436liters per hour or 2.54 useful hp/liter carried for an hour.
Better than the RR supercharger perhaps but don't tell me it is free.
Sounds like smoke an mirrors to me. British used after cooler to cool intake charge. 1.8 AtA is just under 12lb of boost. I am not understanding the last part. the MW/50 carried away the extra 325hp worth of heat out the exhaust? Possibly but what about the engines not using MW/50? like using the engine with C3 fuel and no MW/50.
Using what for speeds? I am having trouble relating power levels to actual speeds. I will give it another try though, Using British figures from Black 6 on Kurfurst's web site. 5 min emergency power, 20 minutes combat power, 20 minute reserve at 2100rpm/1.0 ATA (probably too high) leaves how far can you go at 1065hp for 29 minutes? This assuming you dropped the external tank upon going into emergency power and used no internal fuel on take-off or transferred fuel.
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 may repeat some things but getting bogus facts does not help the argument. Like free hp from increased rpm. or speed differences that don't seem to stand up.
Shortround6
Lieutenant General
You really missed the target with this one.
You seem to have missed that the model 20mm cannon that the Yak-3P was fitted with only weighed 25kg, just about the same as the 12.7mm UB machine gun and 17KG less than the 20mm ShVAK cannon that the earlier versions carried. While the armanet was much more effective it actual weighed NO MORE than the earlier armament of one 20mm gun and two 12.7mm machine guns.
Are you Beginning to see your mistake? For the same weight of guns as 2 Hispanos and two .50 cal Brownings you could fit a Spitfire with SIX of the Russian 20mm B-20 cannon. You might be little light on ammo (105rpg)so you could fit just four such guns and a whole lot of ammo. 120 rounds of Hispano ammo weighs the same as 168 rounds of the Russian ammo. 250 rounds of US .50 cal ammo weigh as much as 153 Russian 20mm rounds.
It is wrong thinking IMHO that if something was done, it means more was possible despite leaving out important facts.
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.
Holding a climb at climb speed is not a reflection of sustained turn ability. Usually, climb speed is under optimum sustained turn performance.
Furthermore, drag because of weight drops off with speed. Which is why heavier aircraft usually accelerate slower from lower speed ranges.
Can i call it low end acceleration? Top end acceleration/performance would not be dealing with drag because of weight.
Which is why on that chart i'm vaguely referring to, if the speed gets slow enough, the Spit does retain a sustained turn advantage.
Also, don't misunderstand me, acceleration is not an indicator of sustained turn ability, just another way to illustrate drag because of weight becomes less an issue with speed.
Acceleration is an important factor, however.
If a plane takes two minutes to reach top speed, while the other takes 1 minute and their top speeds are only with in 10mph, how do you think
that would effect sustained turn performance. (lets assume drag because of weight is not an issue.)
Also, its important to clarify sustained turn, from a turn. One implies the aircraft doesn't slow beyond a certain speed, the other implies a smaller radius (usually for a loss of speed).
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.
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.
It's about both. It's no good being able to accelerate quickly if you lose control.
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.
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 are all sorts of anecdotes around. Better to stick to properly tested figures.
If you are quoting figures from a chart, it is really your responsibility to present that chart. Not mine to look for it for you
So not at high altitude then?
I'd really like to see the chart that shows a P-47D outturning a Spitfire IX at 22,000 ft.
If you compare a Mustang at it's best performance height against a Spitfire with different supercharger gearing at its worst performance height, you're not comparing like with like.
Certainly there might be very brief altitude bands where the Mustang would be superior, but there will be far greater ranges where the Spitfire would turn better.
Parasitic drag on the Spitfire was about the same as the 190, a lot less than something like the P-47.
All flight is about both. Of course, the tighter the turn the more important induced drag becomes.
At high altitude? You did see that the statement was in reference to performance above 20,000ft?
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?
You are arguing for the "light" fighter. That argument was settled long ago in favour of the heavy fighter. An aircraft has certain fixed weight items regardless of size: pilot, guns, ammunition, radio, iff, oxygen etc. The light fighter has to sacrifice somewhere, be it fuel, guns, radios etc.
Fighters spent a lot of time cruising, very little time in combat. Fuel consumption in combat is very much a secondary consideration.
RR approach allowed for low fuel consumption on cruise, high power during combat. Increasing the supercharger power had very little effect on cruise fuel consumption. You can see that by comparing cruise consumption of the Spitfire I (Merlin III): Spitfire Mk I K.9787 Trials Report
and the Spitfire VIII (Merlin 66):
The Spitfire VIII is at 20,000 ft rather than 15,000, which helps account for the better consumption, but even so it's clear that improvements to the Merlin didn't come at a cost of greater fuel consumption outside combat.
Not all 20mm guns are equal. The Russian gun fired a 95 g shell at 790 m/s, the Hispano a 130 g shell at 860 m/s. Tony Williams ranks the power of the Hispano, round for round, at nearly twice that of the Russian 20mm.
I'm just clarifying mach speeds vs actual speed.
The Spit makes mach .88, the P-47 makes mach .85.
Where's the TAS at? oh... they are the same at different heights.
Furthermore, both are dove at 45 degrees, the Spit starts off shallower.
Do you have those to look at, you sound like you are familiar with those.
Why do you think that is?
Not to say the Spit could not be dove more aggressively, i just haven't found anything to show for it.
I think the Spit starting off at a shallower angle is evidence of the need to trim as it increased in speed.
It also shows that constant negative pressure on the control column was required to hold it in dive.
That's why those tests can be informative and probably why the source used them in his book.
When proper procedure was realized, the P-47 was not hard to control or recover from compressibility.
A major contributing factor to accidents or loss of control, was when pilot's intuitively throttled back in the dive which would increase tuck and steepen dive.
Proper procedure recognizes that leaving room to increase throttle in the dive, helps with recovery.
That's a whole 'nother discussion but you can read the manual yourself.
(there is no special code or formula here)
Diving beyond a certain angle is usually not advised in any aircraft.
An aircraft need not reach compressibility in a dive to lose control or become less responsive.
Looking at the manuals, a loss of control can be avoided by using proper pull out procedure.
It doesn't appear that made much difference.
At half throttle, lets assume (2600hp/2) is 1300hp pluss 13,000+ weight. Then the pilot increases throttle as he falls.
Me thinks acceleration isn't an issue unless from very low speeds, such as where acceleration from gravity (32ft per second) is nearly the same for both planes.
Comparing speed limitation charts by two different aircraft is going to lead to issues in the analysis.
It assumes both aircraft use the same instruments, for one.
And usually there is safety margin in both cases.
However, its no secret, the Spitfire had a high mach limit.
Was it faster?
Yeah. But lets put that speed into context.
As shown before, acceleration matters.
Why it matters....see below.
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.
Wouldn't a plane create enough separation to turn around or also zoom? I can't speculate move for move, but the premise that the faster plane eventually catches up ignores those two possibilities.
The Spit catching up also assumes that the dive is extended long enough for it to do so.
In the case of the P-47, it could create that separation relatively fast with out dumping all its altitude, and hold a higher sustained turn to head back in the direction of
the Spit and could do so with out losing the speed it gained from the dive.
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?
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The problems with comparisons usually come down to altitude.
Are you aware of the limitations for boost use on the Spitfire?
I read on this forum, 25lbs was limited to a specific and narrow altitude range, otherwise it was 18lbs max and even that had a limited band width.
It probably says in the manual for the engine.
Shortround6
Lieutenant General
Puttered out is a rather imprecise term. And while you are correct that no Spitfire or Mustang had a full throttle height over 30,000ft they still seemed to perform pretty well up there. It is also well to point out that the P-47s that had critical heights over 30,000ft were rather few in number. In fact most planes have two FTH, one in climb and one for level speed which is ussually several thousand ft higher due to the increased ram in the intake duct. Even the P-47 had a FTH of 28,000ft when climbing while it's FTH in high speed level flight was 32,000ft. A MK XIV Spitifre could do about 421mph at 39,000ft which most people wouldn't consider "puttering out"
True but it is an indication of excess power at a certain speed. That speed being the climb speed. Since any maneuver or departure from straight and level flight except a dive increases drag it is useful to know what sort of power is available to to counter the drag or to accelerate back up to speed when the drag from the maneuver lessens. Granted it does not take into account the drag of a particular airframe. But a heavier plane will have more drag at a given airspeed even if only a small amount. However in a turn things get complicated. Say we have two Mustangs and for what ever reason one weighs 1000lbs more than the other. 8000 to 9000lbs. Difference in speed is just a few mph in level flight. this is due the slightly greater angle of attack the heavier airplane needs to generate the extra lift for the extra weight. Now do a 3 g turn with both aircraft. Both planes need to increase their angle of attack to generate the needed lift. The heavier airplane needs to generate enough lift to counter 27,000lbs not 24,000lbs, it may need even more angle of attack to get this lift compared to the lighter plane than in level flight. it is creating more drag. Neither plane is going full speed any more. While they are not down to climb speed (at least not yet) which plane has the most excess thrust (better power to drag ratio) to help counter the speed loss of the maneuver? The lighter plane or plane with the better climb rate.
Exceptions can probably be easily found but it seems to be an indicator not an absolute rule.
Since most planes (all) could burn off speed in maneuvers faster than their engines could make up for it acceleration is important because it restores the energy potential of the aircraft quicker once the maneuver/s stop or lessen.
If you want to a carry 700lbs worth of of guns and ammo instead of 350lbs worth of guns and ammo you need a bigger plane unless you are willing to sacrifice something else, like protection or range or field length, etc. The bigger plane will have more drag.
try sticking the engine from a Cessna 152 into a Cessna 172 and see what kind of performance you get. Or just stick 350lbs of lead on the floor of the 152 and see what happens. Extreme I know but this almost constant divorce that seems to be going on between the performance of planes and their payload is getting tiresome. If you want a certain amount of guns, ammo, fuel and protection and you want a certain landing speed or field length you make certain choices in the design of the airframe, If the required payload is 20-30% larger or smaller you make other choices.
Shortround6
Lieutenant General
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
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
My statement was in reference to the Spit XIV and contemporary P-47D, probably closer to M, in service.
If the Spit need dive to hold the same speed, it is still less than ideal.
The Spit can slow down to climb, but then hey, you'd be letting them get away...
Lets look at output to define "putter out".
again the engine manual or power chart would say. Its a bit more abstract than a 3 minute google search.
You might notice my google searches are more thorough.
Its probably my band width, though I'm only a 50 ft sea level. I'm sure if our heights were the same you might return better searches.
davparlr
Senior Master Sergeant
I disagree with this statement. Closure rate and pull away rate, the important variables in speed, is an absolute, not a percentage. If you close with a 20 mph advantage, the time that it will take to close on a target at a given distance is the same whether you are traveling 350 mph or 200 mph. If you are on the highway traveling 70 mph and a car passes you at 90 mph, you would say wow, he is traveling fast. That perception would be the same at 500 mph, which would be rather eye opening if your closure rate on a turning rejoin maneuver is 20 mph hot (personal experience!). In my opinion, a real 20 mph advantage in speed is significant, at any speed.
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