Kurfürst
Staff Sergeant
Hi Bill ! 8)
That`s some pretty cool info in the wing profile.
Any specific figures from US etc. testing on the Merlin powered Mustang`s turn time, radius or something like that? I was looking for such data and while ago about USAAF fighters - it turned up nothing specific, unfortunately.
I don`t think we have much of a difference between the two fighters, actually. If we can believe the drag data, both fighters had very similiar, equiv. of ca. 4 sq. feet plate`s drag - the power/speed requirements underline this.. Same for the radiator design, it`s very similiar basically, even though the Mustang`s is a more aerodynamic execution. In the end, both planes reached about the same speed with the same power, so there`s not much in it.
The wing area is 16.05 m2 indeed, the weight of the G-6 is somewhat controversial. One GLC datasheet published in a secondary source tells it`s 3196 kg, but I presume it some special variant and a case of 'lost in translation'. It`s rather illogical given the G-2`s weight of 3037kg, from which the G-6 did not differ much (the 13mm MGs+ammo overall added 40 kg) - unless by 1944 considerable extra equipment in the order of 100kg was added, or we speak of a /U4 variant and again a case of LiT. In any case, datasheets give the weigth of the G-6 as 3100kg, a logical figure while another for the G-6/trop (containing some 50 kg of tropical equipment!) as 3148 kg.
I think it all boils down to variant. The G-14 (not the /AS model) is essentially a low-medium altitude variant, the K-4 is high altitude fighter with a lot more power at altitude. though, especially at high altitude, I don`t think control forces would mean anything - correct me if I am wrong, but high altitude flying technically slow-speed flight at low IAS numbers, with the added problem of most engines loosing power above rated altitude? And low-speed dogfight and controllability is something the 109 definietely excelled in.
Absolutely agree, in fact, I absolutely favour controlled tests over any anecdote..
I don`t think it`s intentional, I think they tested what enemy equipment they had in more or less working order. OTOH, if you read the other AFDU 109G test, for example vs the Tempest, it says the pilots of the 109G are 'emberassed by the opening of the slats' in turns - ie. they weren`t pushing the unfamiliar aircraft to it`s true limits in turns. This is reinforced by the fact that if you look at the 190/109/51 result in turns, it says :
the 51 turns better then the 109
the 51 turns about as well as the 190
which means that logically the 190 should outturn the 109... and as per the 3 German tactical evaluations we know, the Soviet etc. testing, and even by simply common sense, this was not the case. All of it points towards the results are caused by British pilots not pressing the aircraft hard enough in turns, this is somewhat of a returning topos with British test, their test pilots backing off from turn ASA the slats are opening, leaving the party when it just gets started.
Maybe - do you have the complete original papers (not just the test themselves, but attached plane operation diaries, requests etc.) of these tactical trials? I am just working transcribing the papers regarding the 109F-2 tested in the UK, those papers shed light on lot of the background maintaince work and mechanical state of the aircraft, and also valuable pilot comments before they`re squeezed into (and perhaps, made a bit more PC..) the summary report.
As for the 109G-2/trop tested, I have some of the papers from the 1990s issued by modern authorities to declare the aircraft airworthy; these include the operational/mechanical history of Black Six, and it notes several of the original damages the aircraft sustained in air combat in late 1942 before it was captured, still present (splinter marks on airscrew, for example). So, I have reason to believe the aircraft was just patched to be airworthy. Similiarly, there`s a fraction of a German tact. trial on a P-51B somewhere, and it notes some supercharger troubles, 2nd stage simply not working IIRC.
G-10 ..? In June-July? Sorry I don`t get it.
Yup, they`re kits like droptanks, however every single description and photo (inc. the test itself describing as3x20mm cannon, also shown on attached photos) of that particular plane I have seen shows them on (it landed with a droptank too, but I am sure that they took off for trials). The Brits may have not realized the gondolas being kits, given the G-6, they could have though this is some sort of new heavy 109G 'Mark'. Russians seem to have believed the same initially.
Perhaps it would be worthy to narrow it down to some typical variants..? Like, G-14 (normal altitude), G-14/AS (high altitude), P-51D all appearing around June-July 1944, perhaps throw in the basic G-6 still being very much around, playing the role of the small fish in this case, but the big wish when it met with say Spitfire Mk Vs, still being very much around..?
This adds an interesting layer to the discussion, and shows how much complex real life engagment have been, ie. the first (and intially, few) Mustang groups that arrived on the scene usually met with the older, standard G-6s of the '1943 generation'. Against these, the P-51B obviously enjoyed some significant advantages, most notably greater speed at all but especially high altitudes, given it`s high altitude engine, that would also give it advantage in all other flight conditions, ie. turning, at those high altitude regimes. Simply it had more power to work with, but the same wasn`t true when the new P-51s met the new 109Gs, with methanol boost and improved superchargers, and which had comparable power output at all altitudes.
Thoughtful questions - here is what I know and what I believe to be true
The Mustang III in the Test was the 8 March 1944 Test and a.) did not have the aileron seals that were first incorporated in the P51B-10, and b.) did have the 1650-3 Engine that not only had slightly less horsepower than the -7 at War Emergency settings (1600@67" vs 1720@67" but also less power at war emergency high blower at 23,000 (1330@67" vs 1505@19,300ft). Having said this the -3 had MORE hp at 25,800 feet [
The aileron seals significantly reduced control forces in turns and were incorporated in all D and H models. The power settings for the -7 were better than the -3 from SL to approximately 23,000 feet - thereafter the -3 was superior to the -7
Net the P-51D had a 7 1/2 percent increase in power with 110 fuel (the 150 added significan power and boost to this equation) with less than 3% increase in Gross and approx 8% weight over empty weight from B to D version.
I am still researching the wing of the D but believe there was a slight increase in thickness of the NACA airfoil to accomodate the upright guns. This is not yet established fact on my part. I KNOW the first laminar flow dimensions for P-51A were 15% thickness at CL Root Chord/11.4% at the tip I KNOW the D was 16.5%/11.5% respectively - but I don't know whether the B wing was A or B/C/D same except leading edge at fuselage.
That`s some pretty cool info in the wing profile.
Any specific figures from US etc. testing on the Merlin powered Mustang`s turn time, radius or something like that? I was looking for such data and while ago about USAAF fighters - it turned up nothing specific, unfortunately.
The third wild card in this discussion is the combination low drag in the overall airframe combined with incremental thrust obtained by the unique radiator design expelling hot air via the duct.
I don`t think we have much of a difference between the two fighters, actually. If we can believe the drag data, both fighters had very similiar, equiv. of ca. 4 sq. feet plate`s drag - the power/speed requirements underline this.. Same for the radiator design, it`s very similiar basically, even though the Mustang`s is a more aerodynamic execution. In the end, both planes reached about the same speed with the same power, so there`s not much in it.
Well if my figures are right for the 109G-6 it had a wing area of 16.02 M>2=172.44 feet>2 (?), an empty weight of 5908 pounds and gross of 7054 which would yield Wing loadings of 34.26 (empty) and 45.85 (max) versus the P-51D of 32.38 empty and 49.2 (max). The weight of a 51 over Berlin would be closer to 9600 for a max WL of 40.7 and less on the way back
The wing area is 16.05 m2 indeed, the weight of the G-6 is somewhat controversial. One GLC datasheet published in a secondary source tells it`s 3196 kg, but I presume it some special variant and a case of 'lost in translation'. It`s rather illogical given the G-2`s weight of 3037kg, from which the G-6 did not differ much (the 13mm MGs+ammo overall added 40 kg) - unless by 1944 considerable extra equipment in the order of 100kg was added, or we speak of a /U4 variant and again a case of LiT. In any case, datasheets give the weigth of the G-6 as 3100kg, a logical figure while another for the G-6/trop (containing some 50 kg of tropical equipment!) as 3148 kg.
The WL, while important, aren't by themselves the only factor, and the WL of a -14 and the K-4 were less than the G-6 empty and higher loaded... so some physics may lead you to look at the 51 having drained a lot of fuel and a 109 the same condition - then look at control forces between the two at high and medium speeds and altitudes to see a probable favorable condition for the 51 in that arena? (>15,000-20,000) but less than 32,000 in case of G-14?
I think it all boils down to variant. The G-14 (not the /AS model) is essentially a low-medium altitude variant, the K-4 is high altitude fighter with a lot more power at altitude. though, especially at high altitude, I don`t think control forces would mean anything - correct me if I am wrong, but high altitude flying technically slow-speed flight at low IAS numbers, with the added problem of most engines loosing power above rated altitude? And low-speed dogfight and controllability is something the 109 definietely excelled in.
At the end of the day one can judge based on personal anecdotes, published tests, ratios in combat, etc. but the questions of tests still lends more weight if they are fair.
Absolutely agree, in fact, I absolutely favour controlled tests over any anecdote..
I definitely agree.... but the alternative to the conclusions is yet another un-produced set of compariative date to refute the conclusions?
...
I submit that the Brits weren't trying to put a snow job on their bosses if they found serious deficiencies in the Mustang vs Fw190 0r me 109?
I don`t think it`s intentional, I think they tested what enemy equipment they had in more or less working order. OTOH, if you read the other AFDU 109G test, for example vs the Tempest, it says the pilots of the 109G are 'emberassed by the opening of the slats' in turns - ie. they weren`t pushing the unfamiliar aircraft to it`s true limits in turns. This is reinforced by the fact that if you look at the 190/109/51 result in turns, it says :
the 51 turns better then the 109
the 51 turns about as well as the 190
which means that logically the 190 should outturn the 109... and as per the 3 German tactical evaluations we know, the Soviet etc. testing, and even by simply common sense, this was not the case. All of it points towards the results are caused by British pilots not pressing the aircraft hard enough in turns, this is somewhat of a returning topos with British test, their test pilots backing off from turn ASA the slats are opening, leaving the party when it just gets started.
I suspect without proof that many parts, including engines may have been obtained from different sources - no proof by the way but there were quite a few 109s down in USSR, Africa, Italy, UK and being flown by Swiss. I Speculate that spares could be obtained and doubt there was any fuel issue or spark plugs etc deficiency to perform tests with a relaiable engine?
Maybe - do you have the complete original papers (not just the test themselves, but attached plane operation diaries, requests etc.) of these tactical trials? I am just working transcribing the papers regarding the 109F-2 tested in the UK, those papers shed light on lot of the background maintaince work and mechanical state of the aircraft, and also valuable pilot comments before they`re squeezed into (and perhaps, made a bit more PC..) the summary report.
As for the 109G-2/trop tested, I have some of the papers from the 1990s issued by modern authorities to declare the aircraft airworthy; these include the operational/mechanical history of Black Six, and it notes several of the original damages the aircraft sustained in air combat in late 1942 before it was captured, still present (splinter marks on airscrew, for example). So, I have reason to believe the aircraft was just patched to be airworthy. Similiarly, there`s a fraction of a German tact. trial on a P-51B somewhere, and it notes some supercharger troubles, 2nd stage simply not working IIRC.
What was the G-10 flown to UK in June/July timeframe?
G-10 ..? In June-July? Sorry I don`t get it.
And, R6 with Gondola are kits aren't they? Should be easy enough to take off.
Yup, they`re kits like droptanks, however every single description and photo (inc. the test itself describing as3x20mm cannon, also shown on attached photos) of that particular plane I have seen shows them on (it landed with a droptank too, but I am sure that they took off for trials). The Brits may have not realized the gondolas being kits, given the G-6, they could have though this is some sort of new heavy 109G 'Mark'. Russians seem to have believed the same initially.
K- you will note that I have NEVER disputed better one on one performance in favor of 109 over P-51 at SL up to approximately 15,000 feet. Having said that, the P-51A should turn better, most aerodynamics being better than D and 800 pounds lighter
Perhaps it would be worthy to narrow it down to some typical variants..? Like, G-14 (normal altitude), G-14/AS (high altitude), P-51D all appearing around June-July 1944, perhaps throw in the basic G-6 still being very much around, playing the role of the small fish in this case, but the big wish when it met with say Spitfire Mk Vs, still being very much around..?
This adds an interesting layer to the discussion, and shows how much complex real life engagment have been, ie. the first (and intially, few) Mustang groups that arrived on the scene usually met with the older, standard G-6s of the '1943 generation'. Against these, the P-51B obviously enjoyed some significant advantages, most notably greater speed at all but especially high altitudes, given it`s high altitude engine, that would also give it advantage in all other flight conditions, ie. turning, at those high altitude regimes. Simply it had more power to work with, but the same wasn`t true when the new P-51s met the new 109Gs, with methanol boost and improved superchargers, and which had comparable power output at all altitudes.