109's kill ratio (all variants from B to K)

[Batz]

The P-51’s airframe had every spare space filled with fuel tanks. One of the last elements added prior to the Merlin version beng standardized was an 85 gallon tank behind the pilot’s seat. This tank when filled caused a dramatic shift in the aircraft’s centre of gravity, such that if a pilot pulled a turn over 3G’s with the tank full, the possibility of airframe damage was considerable. For that reason, the tank was only filled on long range missions. And orders were specifically penned by the 8th Air Force Commanders that the fuel in the tank was to be burned off before any other fuel, before even fuel in drop tanks. Once the fuel in the tank was below 45 gallons, the aircraft’s centre of gravity returned to normal. Most pilots emptied this tank completely first then started on their drop tanks. That meant that the Mustang went into combat with the behind seat tank empty. In essence it meant the aircraft’s maximum combat weight was actually 510 lbs, (85 gallons) less than the 10,208 lb fully loaded figure. Ie. maximum combat weight was actually 9698 lbs. Which meant that wingloading was actually 41.6 lbs per Sq/ft.

The Mustang carried 269 gallons of internal fuel. That compares to 106 gallons for the 109G10, or 170 gallons for the 190A8, or 138 gallons for the 190D9, or 102 gallons for the Spitfire IX.

As the P-51D carried more fuel, it could fly longer, and burn more, as it burned its larger fuel load, its wingloading improved proportionately more than its opponents.

At 50 % fuel remaining, the P-51D had a wingloading of 40.34 lbs per Sq/ft. It still had a radius of 225 miles.

At 50% fuel remaining, the 109G10 had a wingloading of 41.27 lbs per Sq/ft. It had a radius of 65 miles.

At 50% fuel remaining, the 190D9 had a wingloading of 46.3 lbs per Sq/ft, and a radius of 87.5 miles.

At 50% fuel remaining, the 190A8 had a wingloading of 47.0 lbs per Sq/ft and a radius of 82.5 miles.


At 25% fuel remaining, the P-51D had a wingloading of 38.6 lbs per Sq/ft and a radius of 112.5 miles. Notice that the P-51’s radius with 25% fuel is nearly as good as the G10 at full fuel load.

At 25% fuel remaining, the 109G10 had a wingloading of 40.4 lbs per Sq/ft and a radius of 32.5 miles.

At 25% fuel remaining, the 190A8 had a wingloading of 45.8 lbs per Sq/ft and a radius of 40.1 miles.

At 25% fuel remaining, the 190D9 had a wingloading of 45 lbs per Sq/ft and a radius of 43.7 miles.


At 25%fuel the German fighters better be returning to base, but the P-51 can still fly for a considerable distance.


Powerloading

The same would apply to powerloading for the Mustang at lower fuel loads.

At full fuel load, the Mustang as mentioned above, had a powerloading of 5.93 lbs per hp. At 25% fuel it improves to 5.2 lbs per hp, still not as good as the 109’s but proportionately a better improvement.


What this all tells us, is that while the Mustang wasn’t a very good dogfighter when fully loaded, when it was at a lower fuel load, it would get considerably more nimble.


Combat Flaps

Most aircraft of the WWII era could not deploy flaps over approximately 300 mph, or 480 kph. This applied for the 190’s, 109’s, Spitfires, Yaks, etc. If flaps were deployed at higher than those speeds, they would be damaged. What this meant was that during high speed maneuvers, an aircraft which could successfully deploy flaps, would have a considerable advantage.

The P-51 had a flap setting mechanism which allowed it to drop flaps up to speeds of 425 mph without damage. At very high speeds, only 5 degrees of flaps were used.

A pilot could drop the flaps momentarily, gain a brief advantage in turnrate to achieve a gun solution, and then retract them again to regain speed.

Combat flaps allowed the Mustang to outturn aircraft at high speed which it could not stay with at lower speeds.


Rollrate

The P-51 had a slightly above average rollrate at low and medium speeds, peaking at 94 degrees per second at 310 mph Indicated Airspeed. That does not come close to the 190A, the acknowledged King at low and medium speeds with a maximum rollrate of 165 degrees per second at 250 mph. But the big advantage the Mustang had, was the fact its rollrate was sustained at high speeds. The Mustang still rolled at 85 degrees per second at 400 mph IAS. That compared to the FW190A, which had its rollrate drop off to 70 degrees per second at 400 mph IAS. When compared to other opposition aircraft, the Mustang’s advantage at high speed was even more pronounced.


Aerodynamics

But perhaps the largest single design advantage that the P-51 had was its fuselage and wing shape.

The P-51 used flush rivets, which did not protrude over the surface of the aluminum which covered the wings. This reduced drag considerably.

The radiator intake on the P-51 was set back, behind the wing, on the underside of the fuselage. This avoided affecting most of the airflow over the frame. In addition, The P-51 design used a boundary layer gutter that separated the cooling air intake from the fuselage, preventing the intake from ingesting the boundary layer (the layer of turbulent air close to the skin of the plane) This reduced drag even more. In fact, when the radiator was opened at higher temperatures, the flow of hot air out the back acted as a addition to the thrust of the aircraft, and a net gain in speed of approximately 10 mph was seen.

The P-51 also used a Laminar flow aerofoil design on its wings.

http://nasaui.ited.uidaho.edu/nasaspark/safety/history/airfoils.jpg

Due the wing design with its intention of creating lift, airflow over wing surfaces moves at a high speed than the speed the aircraft is actually travelling. Speeds over the wing surfaces reach high transonic speeds at times, even when the aircraft is travelling much slower. A laminar flow aerofoil reduced the formation of turbulent airflow, which greatly increased drag.

http://nasaui.ited.uidaho.edu/nasaspark/safety/history/lamdiag.jpg

On aircraft with ordinary wings, as speed increases, drag increases expodentially. Laminar flow wings do not suffer as much of a penalty. Which meant that the P-51 bled speed much more slowly than other aircraft at high speeds.

The faster the speeds at which the P-51 met other aircraft in combat, the bigger its aerodynamic advantage. Low G turns at high speeds, zoom climbs, in all these the P-51 excelled.

The P-51 had a drag coefficient of .0176. This compares to the 190A8 and 190D, the most aerodyamically efficient aircraft in large scale production on the German side, which had a drag coefficient respectively of .0278 for the 190A8 and .0242 for the 190D9. On a wing area of 233 Sq/ft that gives the Mustang an equivalent flat plate area of 4.10 sq/ft compared to 5.22 Sq/ft for the A8 and 4.78 Sq/ft for the D9 on a wing area for both 190’s of 196.98 Sq/ft. This means the Mustang is aerodynamically 22% more efficient than the A8 and 15% more efficient than the D9.

This aerodynamic advantage was most noticeable in situations where aircraft were travelling at over their maximum level speeds. At those speeds, normal acceleration and powerloading is no longer effective in propelling the aircraft to go faster, and a major factor governing how an aircraft accelerates in a dive, or how long an aircraft retains speed in a zoom climb is the cleanliness of its airframe.

In these areas, the P-51 is the superior aircraft.


Overall

An overall analysis of the P-51 Mustang reveals an aircraft which, although it doesn’t have a very good climb or low speed acceleration, and which does not excell in low speed high angle of attack turnfighting, has excellent speed through the altitude range and should excell in high speed maneuvers, dives and zoom climbs.

This is what hopefully, we should see in FORGOTTEN BATTLES.


Sources are too numerous to post here, but include the books such as “America’s Hundred Thousand”, test data from NACA and AFDU, as well as original German sources.


Cheers RAF74 Buzzsaw

For those who think the 109s controls "were locked in concrete" above 400 mph are just wrong.

[F4UDOA]

Gsholz,

Do you realize that the P-51D flight data you have posted is for a 10,100lbs airplane?

The 109G10 carries 106 gallons of fuel. The P-51D carries 269 gallons of fuel. So the P-51 is carrying 1640lbs of fuel and the 109 636lbs. So if you take 1,000lbs off of the P-51D how do you think it would climb?

I can tell you that if you take a 12,000lbs F4U-1 at Mil power it takes 8 minutes to reach 20K. At 11,000LBS the same airplane takes 7 minutes to reach the same altitude. That is a huge difference in average rate of climb. This is from test data not AH. Apply that to the P-51D at WEP taking 7minutes to reach 20K at 10,100lbs. At 9100lbs that is 6minutes.

7 minutes= an average rate of climb of 2857fpm

6 Minutes= an average rate of climb of 3333FPM a 16% increase without subracting for equal ammo weight.

With a 16% increase in climb puts the initial rate of climb for the P-51D at 4000FPM.

That is not even including the use of 150 octane fuel.

BTW you ignored my chart. The 109G10 is not faster than the Mustang with 150octane fuel fuel. Did you look at it?

You keep mentioning power to weight but you aren't mentioning that the Cdo of the 109 is so much higher than the P-51 it needs that thrust just to compensate for for it's higher drag. Just look at the Sea level speeds are equal while the 109 has 200HP more. That drag takes its toll in real life acceleration.

Also if you want to prove that the 109 could maneuever at speed you should provide some test data. I have annecdotal evidence from two soucres that say the F4U could roll 180DPS but it still proves nothing.

When comparing the two you should use real life numbers not numbers from the game. If AH were perfect we wouldn't need AH2.

Here is another chart for you reading pleasure.

[VO101_Isegrim]

I have gathered my data regarding the speed and climb characteristics of P-51B and P-51D vs. Bf 109 K. The K-4`s advantage is rather massive, particularly below 7000m.





The P-51B results are from British flights tests. Data for P-51D is from the book America`s Hundred Thousend.

Data for Bf 109 K-4 are from German flight tests with DB 605 DB and DC engine, for 1850 and 2000 HP respectively, and a standard propellor.


Also, while I should note that F4U had somewhat right in that the 109 series were heavy to manouver in pitch, one should note that the Mustang was no better. As Mark Hanna mentioned, the elevator forces were similiar.

There`s also a confirmation to this by Dave Southwood:

 

The Bf109G is heavy to manoeuvre in pitch, being similar to a Mustang.  At 520kph it is possible to pull 4g with one hand, but I find it more comfortable to use both hands on the stick for looping manoeuvres, normally entered at 420kph and 3g.  Pitch trim changes with speed are moderate, and the tail plane trim wheel mounted abeam the pilots' left hip is easy to use.  For a display, I run it at 420-450kph in trim, and then do not retrim.  This causes no excessive stick forces during the display.  Overall the aircraft is straightforward to handle in pitch.

It appears from the description that this wasn`t as restrictive though.

It also agrees with the finding of Society of Experimental Test Pilots, who ran a flight test comparison of the F6F-5, FG-1D (Goodyear F4U), P-47D-40 and P-51D. Chief test pilot was John Ellis of Kal-Aero.

The following give an insight to elevator stick forces and the pilot`s opinion :

MANEUVERING STABILITY stick forces/g at Vmax

FG-1--5 lbs/g (too light)
P-47--7.5 lbs/g (ideal)
F6F--12.5 lbs/g (barely acceptable)
P-51--over 20 lbs/g (excessive)

Regarding stall characteristics :

STALL normal (straight and level decelerating at 1 kt/sec.) and accelerated (constant 3g turn decelerating at 1 kt/sec.)
Aerodynamic warning:

Best--P-47, with buffet 5 kt above stall.
Worst--P-51, no buffet or other warning.

Height loss, accelerated stall:
Best--P-47, 100 ft.
Worst--P-51, 500 ft.
FG-1 and F6F both 150 ft.

Behavior during accelrated stall:

Most predictable and controllable: P-47 and F6F. Both could be flown at will into the pre-stall buffet, which at no time was heavy enough to present problems with tracking, and held at maximum usable lift coefficient with ease. Sideslip became noticeable as wing heaviness correctible with rudder. There was little tendency to depart controlled
flight. The FG-1 suffered severe airframe buffet shortly before the stall, but at the stall there was a strong g-break and rapid right wing drop--no matter which direction the turn. Careful left rudder could prevent wing drop, but then at the stall the aircraft became very unpredictable, bucking and porpoising, with a tendency to a sudden departure.

The P-51 gave no warning whatsoever of an accelerated stall. At the stall, the aircraft departed with complete loss of control, achieving 270-degree of roll before recovery. Departure was accompanied by violent aileron snatch strong enough to rip the control stick from the hand. In short, the P-51 suffered from a Part I deficiency.

Compare to Soutwood on the 109`s :

The idle power stall characteristics of the aircraft are very benign and affected little by undercarriage and flap position.  Stalling warning is a slight wing rock with the stick floating right by about 2 inches.  This occurs 10klph before the stall.  The stall itself is a left wing drop through about 15 degrees with a slight nose drop, accompanied by a light buffet.  All controls are effective up to the stall, and recovery is instant on moving the stick forward.  Stall speeds are 155kph clean and 140kph with gear and flap down.  In a turn at 280kphwith display power set, stall warning is given by light buffet at 3g, and the stall occurs at 3.5g with the inside wing dropping.  Again, recovery is instant on easing the stick forward.  One interesting feature is the leading edge slats.  When these deploy at low speeds or in a turn, a 'clunk' can be heard and felt, but there is no disturbance to the aircraft about any axis.  I understand that the Bf109E rolled violently as the slats deployed, and I am curious to know the difference to the Gustav that caused this.

The control heavyness of the 109 only applied to the elevators, the ailerons and rudders were light.

In fact, I have 3 different sources which all state that the aileron forces were light, a German, Finnish test, and Soutwood`s and Hanna`s words, all indicate that even at 450-480 km/h IAS range, stick force required for full deflection was a mere 20 lbs. Very light indeed. The measured roll rate at this speed was 80-95 degree/sec at this speed, again, rather good.

[GScholz]

Originally posted by F4UDOA
Gsholz,

Do you realize that the P-51D flight data you have posted is for a 10,100lbs airplane?

The 109G10 carries 106 gallons of fuel. The P-51D carries 269 gallons of fuel. So the P-51 is carrying 1640lbs of fuel and the 109 636lbs. So if you take 1,000lbs off of the P-51D how do you think it would climb?

I can tell you that if you take a 12,000lbs F4U-1 at Mil power it takes 8 minutes to reach 20K. At 11,000LBS the same airplane takes 7 minutes to reach the same altitude. That is a huge difference in average rate of climb. This is from test data not AH. Apply that to the P-51D at WEP taking 7minutes to reach 20K at 10,100lbs. At 9100lbs that is 6minutes.

7 minutes= an average rate of climb of 2857fpm

6 Minutes= an average rate of climb of 3333FPM a 16% increase without subracting for equal ammo weight.

With a 16% increase in climb puts the initial rate of climb for the P-51D at 4000FPM.

That is not even including the use of 150 octane fuel.

BTW you ignored my chart. The 109G10 is not faster than the Mustang with 150octane fuel fuel. Did you look at it?

You keep mentioning power to weight but you aren't mentioning that the Cdo of the 109 is so much higher than the P-51 it needs that thrust just to compensate for for it's higher drag. Just look at the Sea level speeds are equal while the 109 has 200HP more. That drag takes its toll in real life acceleration.

Also if you want to prove that the 109 could maneuever at speed you should provide some test data. I have annecdotal evidence from two soucres that say the F4U could roll 180DPS but it still proves nothing.

When comparing the two you should use real life numbers not numbers from the game. If AH were perfect we wouldn't need AH2.

Here is another chart for you reading pleasure.

Did you even read my post? I did a test with a fully laden 109G10 WITH DROPTANK and compared it with a P-51D WITH 50% FUEL. The 109 was still vastly superior in the test.

Parasitic drag does not become a major factor until high speeds are reached, at low speed induced drag and weight are the major factors affecting acceleration. The 109G10 and K4 accelerated much faster than the P-51D.

I didn't ignore your chart, It confirmed my statement. I never said that the 109G10 was faster than a P-51D with 150 octane fuel, I said that the 109K4 was equal in speed on the deck (approx. 380 mph), but superior at altitude. The 109G10 still out climbed the P-51D though. Your chart states that a not cleaned up for testing P-51D (A) did approx. 380 mph on the deck

I don't need to prove that the 109 could maneuver at speed, what evidence do you have that it didn't?

I use data from Aces High because believe it or not I don't have the luxury of flying real WWII planes in mock combat. I play Aces High and the performance in the game is what is important to me.

[VO101_Isegrim]

I also found this in my archieves,

Acceleration, as calculated by Greg Shaw. At SL, at Full Throttle, from 250mph TAS:

in feet/seconds


109 K-4 : 6.85
La-7 : 6.58
190 D-9 : 6.05
109 G-14: 5.59
Spit XIV: 5.55
109 G-10: 5.50
Yak-9U : 5.27
190 A-8 : 4.97
Yak-3 : 4.80
P-38L-5 : 4.75
109 G-2 : 4.62
P-47 M-5: 4.49
SpitIXLF: 4.41
109 G-6 : 4.22
P-38J-25: 4.17
F-6F : 4.09
F-4U1D : 4.08
P-47D-25: 3.79
P-51D-25: 3.34

I checked the Mustang acceleration data with America`s Hundred thousend, and it`s matches very well.

Nothing of a surprise, the K-4 had drag comparable to the P-51, but was a lot lighter and had a more powerful engine (Daimler Benz rules...).

Relevant powerloadings at SL were :

109 K-4 : 588 HP / t
P-51 D  : 363 HP / t

Regarding Cd0 numbers... they are pretty irrevelant. They are useless for comparing aerodynamics of different shaped and sized planes. Don`t ask me, ask the NACA, they say the same.

Besided, that sand in the eye about Cd0s reminds me the historical conversation between Ersnt Heinkel and Willy Messerscmitt after the Bf 109 was choosen over Heinkel`s design for a fighter. Heinkel was arguing that he was building more aerodynamic planes.

Messerschmitt reply : "Well, I build fast ones."

[niklas]

The +25lb boost chart does not reflect reality. There exist 2 pages from detailed test report of a Mustang running at 25lb with a 1650-7 engine. Topspeed TAS was 355mph @ +18lb and 379mph @ 25lb (sealevel).
What´s strange is the fact that they even added +5mph to IAS.

I assume this comparision chart shown here is for highly tuned machines, probably lightly armed, specially prepared V1-chasers.

niklas

[VO101_Isegrim]

Originally posted by Nomak
Are you serious?  How about severe compression problems?

How about the auto deploying slat on the wing that killed many, many pilots?

How about the fact that 109s were so difficlut to take of and land with that half the 109s lost in the war were lost to take off and landing accidents?

Jesus, I haven`t read such massively WRONG statements for a long time.

Severe compressibility problems ?
Slats (!!!!!!!!) killing pilots ?
Half were lost in landing accidents ?

Where did you got all that BS ?

[VO101_Isegrim]

Originally posted by niklas

I assume this comparision chart shown here is for highly tuned machines, probably lightly armed, specially prepared V1-chasers.

niklas

That`s right Niklas, the test were done with planes intended as V-1 chasers, all were cleaned up greatly. In fact some of the machines were stripped of equipment, ie. wingtips, mirrors, antenna masts, bombracks etc. were removed.

[Batz]

Originally posted by VO101_Isegrim
Jesus, I haven`t read such massively WRONG statements for a long time.

Severe compressibility problems ?
Slats (!!!!!!!!) killing pilots ?
Half were lost in landing accidents ?

Where did you got all that BS ?

Didn't you know the lw never had any planes that could do anything more then fly straight and level? Then out of those it was a miracle just to take off and land with out killing yourself and destroying the plane.

[MiloMorai]

Originally posted by VO101_Isegrim
That`s right Niklas, the test were done with planes intended as V-1 chasers, all were cleaned up greatly. In fact some of the machines were stripped of equipment, ie. wingtips, mirrors, antenna masts, bombracks etc. were removed.

How does one remove the wingtips from a P-51? Most P-51s did not have mirrors - was not a standard fitting. All P-51s did not have bomb/drop tank racks as standard. How does one communicate with ground control if the antenna mast is removed?

Oh btw, how was your "vacation" from Ubi?

[VO101_Isegrim]

You still have reading comprehension problems Milo. I said "some".

Vacation ? What vacation, Briddy ? Dreaming again ? I guess so.

[Nashwan]

Just to make it clear, Isegrim's charts show the 109K4 at 1.98 ata, which wasn't authorised until March 45, and 1.8 ata, which wasn't authorised until Feb 45.

His figures for the P-51 are with 100/130 fuel, not the 100/150 they switched to in summer 44. 100/150 allowed higher manifold pressure, up to 81 in HG in RAF service, a bit less in the 8th AF. That gave up to 2000 hp in the Mustang.

In fact some of the machines were stripped of equipment, ie. wingtips, mirrors, antenna masts, bombracks etc. were removed.

None of the planes had aerials removed. The Mustang had "a small projecting bracket at the base of the whip aerial removed", which doesn't mean the whole aerial.

The Mustang had the bomb racks removed, and a quick clean up of the paintwork.

As recieved from the squadron, with badly chipped paintwork, bomb racks (and "small projecting bracket"!) it had a speed of 383 mph at sea level. With the bomb racks removed, aerial bracket removed, and paint cleaned up speed went up to 403 mph at sea level.

[MiloMorai]

Originally posted by VO101_Isegrim
You still have reading comprehension problems Milo. I said "some".

Vacation ? What vacation, Briddy ? Dreaming again ? I guess so.

Not as bad as yours Barbi.

You going to call me a pediphile like you did to someone at Ubi?

[F4UDOA]

Gsholz,

As soon as I saw you are basing your results on AH I disregard them. They are meaningless in the real world. If your only concern is the current AH FM then I won't even bother with the discussion.

However in the air where airplanes fly things are different.

An aircraft with higher drag will take longer to accelerate than one with lower drag even with higher HP many times. Drag is a huge factor especially cdi. Your cruise drag of the 109 is what cost so much. Fact is the pony could do a fast cruise of 400MPH at altitude that the 109 could never match. This was due to high cdi which slows the 109's acceleration drastically.

I have the P-47C AFDU where it accelerates as well as the P-38F despite less HP and worse power loading.

VO101_Isegrim actually proves my point. In the report you posted that shows stall and stick forces it also shows the P-51D out acclerating the F4U-1D, F6F-5 and P-47D despite having the worst power loading.

So much for Mr.Shaws calculations.

I already know the Pony has high elavator forces but the ailerons were very good.

Instead of pointing to your sources for the 109's ailerons why don't you post them?

Also your data you keep refering to is clearly marked in AHT as 10,175lbs P-51D for climb and climb times. In practical combat that airplane would weight less than 9,000lbs.

You insist at comparing the heaviest possible configuration to a light 109.

Why don't you ask a surviving German pilot how he felt?

[GScholz]

Ok F4UDOA, I have a few questions for you.

First, do you have any data on the high alt performance of the P-51D using 150 octane fuel?

Second, since 150 octane fuel does not by itself increase HP did they replace the supercharger or merely increase boost pressure where the original blower could, i.e. at lower altitudes?

Thirdly, when did the P-51's start using 150 octane fuel for most if not all operational units (as opposed to just a few specialized ones)?

Fourthly, You say that combat weight for the P-51D was less than 9000 lbs. Does the P-51D have enough fuel to fight and then return to England from Berlin if it is weighing less than 9000 lbs?

Fifthly, you state that the 109 was "locked in concrete" above 400 mph, what documentation can you provide that support this?

Sixthly, your acceleration theories do not match with (what I preserve as) reality. Drag is not the most important factor in accelerating at low speeds so if the 109 is faster, lighter and have more HP it MUST accelerate faster than the P-51D at low speeds. What documentation can you provide that refutes this logic?

Seventhly, do you have any quotes from 109G10 and/or 109K4 pilots that say they felt the P-51D was superior?