Corsair vs. BF 109G,K or FW 190's

[FLYBOYJ]

Great info Crumpp!

[Crumpp]

Originally Posted by drgondog

Thanks for taking the time - I've been out of flight mechanics for too long.

The analysis works up to 1st gear FTH. It does not include second gear effects although given a good engine chart it would be entirely possible to do an analysis.

Although we use power available, the prediction actually uses thrust production as a function of Thrust Horsepower and velocity with an assumed propeller efficiency of 85%.

I used 85% as it is considered the norm for propeller aircraft predictions. I do have good thrust horsepower data on the Focke Wulf series. It shows an Np depending on the advanced ratio from the low 60's to the mid 90's. I do have some data on the P51's propeller as well. It shows a similar trend in Np.

So assuming an Np of .85 is not going to change the conclusions of the prediction. There is no specific performance conclusions that can be made from any of these predictions. In the realm of significant digits though, the prediction is accurate for determining trends in performance.

Specific performance is far beyond the scope of one man who has to feed a family. It would take an engineering team with mounds of data and computer time to do that.

We can accurately say that the P51 series and the FW190 series are close enough that pilot skill makes all the difference and that aircraft configuration is a major contributing factor.

Two clean aircraft in similar loading configuration at or below FTH gives the FW190A8/D9 series a slight advantage at low to mid velocity. At high velocity the P51 series holds a slight advantage. Roll rate would be more important between these two aircraft as the aircraft which establishes the turn first will widen its advantage. Here again, at low velocity the FW190 wins out and the P51 series wins out at high velocity with the mid range leaving the two aircraft equal.

If the configurations were dissimilar, then the clean fighter would hold the advantage.

We cannot make a blanket statement that either aircraft design is superior to the other in horizontal maneuvering.

Offhand, At 35K the V-1650-3 equipped P51 series would hold a wider advantage but the V-1650-7 equipped P51 series would be very close.

I could run an analysis for you but will have to add it to my list of "things to do" after the Bf-109/Spitfire analysis..

You can also see by examining such aircraft as the Zeke 52 and P47D-22 some interesting trends. Although the Zeke 52 can easily outturn the P47 as it can reach a high Nzmax at some very low velocities, the P47 is the superior fighter. If the P47D-22 stays in its best turn velocity range, the Zeke 52 cannot touch it. It simply does not have the power available at velocity. The P47D-22 for example can sustain 2.75G’s at 250KEAS while the Zeke 52 can only fly wings level at 250KEAS.

It is easy to see why the IJNAF did not retain air superiority in the Pacific.

All the best,

Crumpp

[Crumpp]

Thank you FlyboyJ. I hope everyone finds it of value and it lends some insight into the scientifically achievable performance of these aircraft.

All the best,

Crumpp

[Soren]

According to your chart the Dora-9 holds a clear advantage over the P-51D at all speeds, which is entirely correct according to most sources.

[Crumpp]

According to your chart the Dora-9 holds a clear advantage over the P-51D at all speeds, which is entirely correct according to most sources.

Certainly if we are flying a Dora-9 using C3 fuel and MW50. The more common B4 with the Oldenburg system was a much closer match.

I caution you not to read into these charts. They are not predicting specfic performance. For example all we can conclude is that at 300KEAS the FW-190D9 clean configuration overload fighter variant with C3 and MW50 had a turn advantage over the P51D clean configuration overloaded fighter. We cannot say that it was could pull .74g's more than the P51. All we can say is in the realm of significant digits, the FW190D9 C3 was advantaged but not by a large margin.

Consider too just how many pilots could take advantage of this level of superiority.

All the best,

Crumpp

[Sgt. Pappy]

Coming from a video game-based community, I can't really say much that is of true value, but from what I've learned from the Aces High II flight models, the F4U is quite superior to the Mustang in all but speed and zoom/sustained climb. Compared to the 190-A5 for example, it dives better, zooms better, and turns tighter. The 109K-4 is likely to eat the F4U-1 series (that is the F4U-1, -1A, etc) alive but the contemporary of the K-4 is the F4U-4 which is more or less on par with the Kurfurst, IMO. It has been said that the Kurfurst is better in everything but roll but the deployment of the highly efficient flaps of the F4U in addition to the lower wingloading allows it to get the Corsair just as maneuverable as the wing-slatted 109.

The slotted flaps of the Corsair offer it far greater maneuverability than both the P-51 and the 190 due to a much higher Clmax and its higher power loading affords it better acceleration. I don't consider range to be a very important factor in fighters; after all, fuel load never helped bombers dogfight so why would it help fighters?

Anyhoo, here's a good link that might be interesting: The Math Behind Turning

[Soren]

Originally Posted by Crumpp

Certainly if we are flying a Dora-9 using C3 fuel and MW50. The more common B4 with the Oldenburg system was a much closer match.

I caution you not to read into these charts. They are not predicting specfic performance. For example all we can conclude is that at 300KEAS the FW-190D9 clean configuration overload fighter variant with C3 and MW50 had a turn advantage over the P51D clean configuration overloaded fighter. We cannot say that it was could pull .74g's more than the P51. All we can say is in the realm of significant digits, the FW190D9 C3 was advantaged but not by a large margin.

Consider too just how many pilots could take advantage of this level of superiority.

All the best,

Crumpp

Copy that Crumpp.

However considering the lift-loading of the FW-190 was lower as-well we can safely assume that the FW-190 can pull more G's. The light stick forces of the Fw-190 series, esp. in elevator control, also made sure it was far more maneuverable at high speed.

According to NACA the 23000 series airfoils from 15 - 9% thickness ratio had an average free flow CLmax of around 1.60. This is much higher than the laminar flow airfoil on the P-51.

[Crumpp]

However considering the lift-loading of the FW-190 was lower

I don't think this is correct, Soren. The Dora has higher wingloading at TO weight than the P51D series.

The Dora has more power available though as it has lower drag than the Anton variants while increasing thrust production.

You are correct on the higher Clmax. Clmax required of the P51D series is 1.50 and the Clmax required of the Dora-9 is 1.58 if these aircraft are to reach the stall speeds provided by the manufacturer.

here's a good link that might be interesting:

That is pretty much the same methodology I used.

All the best,

Crumpp

[Soren]

Don't know the stall speeds of each a/c, however I do know that the Dora-9's landing speed was 167 km/h and that the P-51's landing speed is 170 km/h.

The Dora-9 also has a much shorter take-off run, both to point of take-off and to clear a 20m high object, which it actually does on a shorter distance than it takes the P-51D to clear a 15m high object.

[drgondog]

Originally Posted by Crumpp

The analysis works up to 1st gear FTH. It does not include second gear effects although given a good engine chart it would be entirely possible to do an analysis.

I felt this to be true - which is why I asked the question earlier.. what was running through my mind was a.) Hp/Thrust as function of altitude - each fighter with a different profile , .b) prop efficiency at recommended versus max rpm, c.) relative energy losses beteen the two ships in high G level turn at different altitudes - not only as function of induced drag but the overall airframe wing/body combination - your profile does an excellent job of consolidating relative merits w/o going throug a full blown performance analysis

Although we use power available, the prediction actually uses thrust production as a function of Thrust Horsepower and velocity with an assumed propeller efficiency of 85%.


Specific performance is far beyond the scope of one man who has to feed a family. It would take an engineering team with mounds of data and computer time to do that.

and of course the inevitable flight tests with pilot skill and knowledge of the airplane as another set of variables

We can accurately say that the P51 series and the FW190 series are close enough that pilot skill makes all the difference and that aircraft configuration is a major contributing factor.

That's basically what the 8th AF directives said about the two in air to air combat - particularly at or below medium altitudes, low to medium speed.

Two clean aircraft in similar loading configuration at or below FTH gives the FW190A8/D9 series a slight advantage at low to mid velocity. At high velocity the P51 series holds a slight advantage. Roll rate would be more important between these two aircraft as the aircraft which establishes the turn first will widen its advantage. Here again, at low velocity the FW190 wins out and the P51 series wins out at high velocity with the mid range leaving the two aircraft equal.

If the configurations were dissimilar, then the clean fighter would hold the advantage.

We cannot make a blanket statement that either aircraft design is superior to the other in horizontal maneuvering.

Offhand, At 35K the V-1650-3 equipped P51 series would hold a wider advantage but the V-1650-7 equipped P51 series would be very close.


I could run an analysis for you but will have to add it to my list of "things to do" after the Bf-109/Spitfire analysis..

Thanks, Crump - you've given me what I need - except to pose one question about 109G-6 versus 51D in context of a.) relative disadvantage of high control forces of 109 at high speed versus better flight control at or near stall for experienced 109 pilot with slats working? Would your methodolgy attempt to analyze such inputs? .



Crumpp

Thanks again Crumpp

[Soren]

The "high" control forces of the Bf-109 at high speeds could easily be dealt with with a little two hand pull, so there should be no restraint in pitch. However roll rate did get affected at high speed, the forces being higher in this area as-well as being harder to counteract.

[Glider]

I think we need to understand the definition of high speeds. In the 109 life started to get scary at around 700-720km/h (around 435-450mph) speeds at which the P51D was still fairly easy to manoevre

So at very high speeds the P51 has a significant advantage.

[Kurfürst]

Date :- 28th October 1941
Ref : - AFDU/3/19/44

TACTICAL TRIALS - Me.109F AIRCRAFT

... and the aircraft was dived at 420 indicated and the aileron control still found to be quite good, though considerably heavier. Elevators quite good but not very light.

7 . No manoeuvrability trials were carried out against other aircraft but the Me.109F was dived up to 420 m.p.h., I.A.S., with controls trimmed for level flight and it was found that altough the elevators had become heavy and the ailerons had stiffened up appreciably, fairly tight turns were still possible.

As I understand, low control forces are advantagous for high instantanous manouvers, ie. brief snap turns, but they provide no advantage in sustained turns, in fact, below a certain level of control force, it`s much more difficult to ride the stall - and get the optimum sustained turn rate - due to the control`s sensitivity.

[AL Schlageter]

Flying Limitations of the Me 109 G (from: Technical Instructions of the Generalluftzeugmeister, Berlin, 28th August 1942.)

Reference Me 109 - wing breakages. Owing to continually recurring accidents caused by wing breakages in Me 109 aircraft attention is drawn to the following:

(1) The maximum permissible indicated airspeeds in the different heights are not being observed and are widely exceeded. On the basis of evidence which is now available the speed limitations ordered by teleprint message GL/6 No. 2428/41 of 10.6.41 are cancelled and replaced by the following data:

Up to 3 km (9,842 ft.) 750 km/h. (466 m.p.h.)
At 5 km (16,404 ft) 700 km/h. (435 m.p.h.)
At 7 km (22,965 ft) 575 km/h. (357 m.p.h.)
At 9 km (29,527 ft) 450 km/h. (280 m.p.h.)
At 11 km (36,089 ft) 400 km/h. (248 m.p.h.)

These limitations are valid for the time being for all building series including the Me 109 G. A corresponding notice is to be placed upon all air-speed indicators in aircraft.

(2) Yawing in a dive leads to high one-sided wing stresses which, under certain circumstances, the wing tip cannot support. When a yawing condition is recognised the dive is to be broken off without exercising force. In a flying condition of yawing and turning at the same time correction must be made with the rudder and not the ailerons. The condition of wing tips is to be examined and checked with TAGL. Bf 109 Nos. 5/41 and 436/41.

(3) Unintentional unlocking of the undercarriage in a dive leads also - especially if only one side unlocks - to high wing stresses. Observation and the carrying out of TAGL. No. 11/42 and the following numbers is, therefore specially important.
Note. Trouble has been experienced owing to undercarriage unlocking in a dive and a modification has been brought out to prevent this.

.......The dive speed limits listed above are also to be found in Vorläufige Fluggenehmigung BF 109 G-2 and G-6

Dive limitations from: Bf 109 G-2, G-4, G-6 Bedienungsvorschrift, June 1943 edition

Dive: Adjust trim in such a way that the airplane can be held in a dive. The elevator forces and tailplane loads become great at high speeds. The tailplane adjustment must work perfectly; otherwise shifting of the tailplane is not possible.
Sturzflug: Trimming so einstellen daß das Flugzeug durch Drücken im Sturzflug gehalten werden kann. Die Höhenruderkräfte und Flossenbelastungen werden bei hoher Fahrt sehr groß. Hemmung der Flossen verstellung muß einwandfrei arbeiten; sonst ist Selbst verstellung der Flosse möglich.

Maximum diving speed 750 km/h. Hard aileron manipulation while diving leads to failure, particularly when pulling out. Höchstzulässige Sturzfluggeschwindigkeit 750 km/h. Harte querruder betätigung im Sturz und besonders beim Abfangen führt zum Bruch.

[Kurfürst]

Nice flamebait.