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

[AL Schlageter]

I have 364 mph for the 51B/1650-7/67", and 354 mph for the 51D/1650-7/67".
This translates to about 1630 HP at SL.

The speeds when 25lb boost and 150pn fuel is ________?

Notes :
The given performance figures are going to be reached with well-built serial production machines for certain.

Yet it was questioned when 1.98ata was being tested, 'why go for 1.98 when the airframes are is such bad condition?'

 

[Kurfürst]

Milo,

Perhaps search for another board for your feuds and flamebaitings.

 

[Glider]

IMHO it`s rather futile to speculate how good 'British testpilots' were, when the facts are quite clearly there.

And what experience they had with the aircraft BTW?

The AFDU also tested a 109F in 1941 for example. The pilot had the opportunity to gain precisely 25 minutes worth of flying 'experience' in the 109 before he attemped to fly comperative trials against a Spitfire pilot with what - hundreds of flying hours in a Spitfire? Even an 1944/45 Luftwaffe rookie in the 109 had at least a dozen or two flying hours in a 109 before entering combat.. you`re telling me that after just 25 minutes of familiarisation, the pilot was capable to push the aircraft to it`s final limits..?!

Attempted because the aircraft was in such a poor shape they had to cancel the trials to make some makeshift repairs, despite which oil pressure was still abnormal in the 109.

The battle damaged 109G-2/trop they tested vs the P-51B was hardly in any better shape. It`s condition is detailed in the Middle East report that can be found on my site.

I mean, you can keep ignoring and denying these circumstances, but to what end, I cannot imagine. Any reasonable man would see that ill-maintained aircraft in which the pilot has nil experience ain`t gonna shine in any comparison when flown against well maintained aircraft flown by a pilot who has extensive knowledge of flying the type.

What I find amusing is your continual knocking of the tests, because the planes were battle damaged it makes the tests far less that perfect. Of course they were damaged, how else would the allies get hold of them!!!. The tests were the best that could be done in the situation available. No doubt as were the German tests with aircraft they captured in similar situations.

For sake of argument lets say the tests (both allied and German) were done using 90% of the performance available because of damage, uncertainty re maintanence, not wanting to lose almost unique aircraft, whatever. The question is does it matter?

I would suggest the awnser is no. What matters is the ability to give advice to the average pilot on how best they can deal with the opposition. The average pilot of any airforce will not get the absolute best out an aircraft. If your average opponent is getting 90% out their aircraft then the test and more importantly the advice remains valid.
We all recognise that aces and highly experienced pilots will get more out of aircraft they are familiar with, than the average squadron pilot.

On a slightly different topic the experience of the Test pilots in the German aircraft. In the UK testing of captured aircraft was a two stage process.
The first stage was testing the handling of the aircraft and pushing it as far as they could in the circumstances.
The second stage handled by a different unit covered the tactical trials.
As one person didn't carry the whole process through it may have some impact on the time in the cockpit.

One thing that I have noticed is that most of the reports of tactical trials are from the Allied point of view. Germany would have carried out similar tests but I have been unable to find many reports, do you have any idea where I can find them?

 

[Kurfürst]

There`s a fraction of a German report available comparing G-6/AS, G-6, A-8 v. P-47D and P-51 (presumably B, a 'newest model Mustang', report the dated 19-6-44).

Unfortunately, most of the report appearantly went missing due to damaged microfilms, and the part about the Mustang is limited to general description and some words on generic flying/handling, but no comparison; it is mentioned that flight of the Mustang had to be abandoned above 7000m due to faulty supercharger..

 

[FLYBOYJ]

I think its worth remembering that in 1943 the British set up the Empire Test Pilot Training school so that all test pilots were trained to the highest degree and used common standards.
It was the first school of its kind and is still recognised as a leading establishment of its kind.
Its also worth noting that one of the reasons it was set up, was because of the loss ratio of pilots untertaking test pilot duties. From this its safe to work on the premise, that the test pilots were not afraid of pushing the boundry to the limit, quite the opposite.

BINGO!!!! And I would think that loudly deploying L/E slats (In any aircraft) weren't going to be a deterrent from any of these folks from performing their mission...

 

[davparlr]

Exactly how big a climb rate are you under the illusion that the F4U-4 possesses Davparlr ???

My illusion on climb rates for the F4U-4 was determined by this site:
http://www.wwiiaircraftperformance.org/f4u/f4u-4.pdf

Climb rates of the F4U-4 vs. Fw-190D-9 and Bf-109K

SL
F4U-4 4800 Fw-190D-9 4330 Bf-109K-4 4400

10k
F4U-4 4800 Fw-190D-9 4320 Bf-109K-4 4020

20k
F4U-4 3800 Fw-190D-9 3054 Bf-109K-4 3520

30k
F4U-4 2000 Fw-190D-9 1476 Bf-109K-4 1900

I have 364 mph for the 51B/1650-7/67", and 354 mph for the 51D/1650-7/67".
This translates to about 1630 HP at SL.

The 109G/K performance figures depend on the type you speak of.
All of these are for 1800 PS at SL, or a bit below 1800 HP.

Bf 109G-14 : 352 mph
Bf 109G-14/AS : 348 mph
Bf 109G-10 : 349 mph
Bf 109K-4 : 370 mph

I don`t see breathtaking differences here. The Mustang D is slightly better than the 109G, and apprx. the same aerodynamic effiency as the 109K.

I have no problems with your numbers.

Airspeed vs. HP at SL where "q" is max is probably the best method of judging the propulsive efficiency of an aircraft. At this condition, where every mph comes at the biggest HP cost, the 23 – 27 mph advantage of the P-51D is not a "slight" difference but a significant difference and an operational advantage at any altitude. Imagine cruising down the freeway/interstate/autobahn at 70 mph (112 km/hr) and a car goes by you at 93 mph (150 km/hr). That's how fast a P-51D will go by a Bf-109G-14 at SL. Oh, by the way, if that Mustang is a P-51B, that passing car would be doing 104 mph (167 km/hr) (remember your doing 70)!

The Bf-109K-4 is a much later version and is more comparable to the P-51H. But in any event, it is interesting to note that the P-51D is still slightly faster at SL (insignificant) and the P-51B is noticeably faster.

 

[Kurfürst]

I have no problems with your numbers.

Airspeed vs. HP at SL where "q" is max is probably the best method of judging the propulsive efficiency of an aircraft. At this condition, where every mph comes at the biggest HP cost, the 23 – 27 mph advantage of the P-51D is not a "slight" difference but a significant difference and an operational advantage at any altitude.

The point being the P-51D does not seem having '23 – 27 mph advantage' over any of these aircraft.

At least, the 354mph achieved by the P-51D/67" vs. the 352mph achieved by the G-14 is not ~25 mph difference in my book, more like 2 mph (though the 109 achieves it with slightly more power available, so on even footing, the Mustang is probably a bit better, say 360-365).

The Bf-109K-4 is a much later version and is more comparable to the P-51H.

How come, the P-51D was introduced what, June-July 1944, the 109K in October the same year. 'Much later' - like what, four months...?

The P-51H, with it`s performance apprx. on the level of the 109K, appeared in when, something like August 1945 on operation, some 10 months after the 109K (I am not sure about the 51H ever seeing combat in WW2)..?

But in any event, it is interesting to note that the P-51D is still slightly faster at SL (insignificant) and the P-51B is noticeably faster.

Still, the 355 mph or so achieved by the P-51D in normal condition at 67" does not seem to me higher than 370 mph achieved by the 109K at 1.8ata (alternate comparison can be made at similiar power at 81"/1.98ata, at comparable power ie. 379/377mph. Again not much of a difference).

PS : You might want to add the 1.98ata climb rates into your climb rate comparison to keep the playing field even, also I can`t understand why the F4U4 climb figures you are showing are so much higher than every other Navy document shows.

Ie.

SL
Your F4U-4 4800 vs 4400 reported for F-4U4 at 12450 lbs, at 70", inOctober 1944 specs.

10k
Your F4U-4 4800 vs ~4300 reported for F-4U4 at 12450 lbs, at 70", in October 1944 specs. (revised and superseed to 4000 fpm in April 1945)

20k
Your F4U-4 3800 vs 2980 reported for F-4U4 at 12450 lbs, at 70", in October 1944 specs.
(revised and superseed to 3270 fpm in April 1945)

30k
Your F4U-4 2000 vs ~1400 reported for F-4U4 at 12450 lbs, at 70", in October 1944 specs

Your data is very significantly higher than the official US performance data reported in October 1944. Why?

 

[AL Schlageter]

24 April 1944

Flight Tests on the North American
P-51B-5-NA Airplane, AAF No. 43-6883

Maximum speed at sea level (67" Hg. manifold pressure 3000 RPM) - 371.0 MPH

15 June 1945

Flight Tests on the North American
P-51D Airplane, AAF No. 44-15342

Maximum speed at sea level

War Emergency power (3000 RPM and 67") 375 MPH
Military power (3000 RPM and 61") 364 MPH
Normal Rated power (2700 RPM and 46") 323 MPH

 

[Soren]

What a surprise, Mike William's site again - thought you guy knew better by now not to use his site as reference for German a/c performance.

The FW-190 Dora-9 has a climb rate of 4,400 ft/min, the Bf-109K-4 over 5,000 ft/min ! Even with the thin experimental DünblattSchraube the Bf-109 K-4 boasted a 4,800 ft/min climb rate!

PS: Have you got time to climb figures for the F4U-4 as-well ?? I'd like to see wether the F4U-4 is able even to beat the Dora-9 to 10km.

And about your assumption on the RAF test-pilots, well thats all it is, an assumption.

Kurfürst and I have both provided more than enough evidence as proof that the British test-pilot flying the 109 didn't push it beyond the deployment of the slats.

Let me sum it up here:

1.) The British test-pilot makes the comment: "The 109 being embarrased by the opening of its slots", this alone being a clear enough sign that he wasn't pushing past slat deployment.

2.) During the British comparative testing the test-pilot didn't even accomplish to turn the 109 as tightly as the FW-190 or P-51, eventhough the Bf-109 clearly always out-turned the FW-190 P-51 in German Soviet comparative testing.

3.) Several German experten make it clear that green 109 pilots didn't push past slat deployment, the slight notch and loud bang sometimes heard convincing the green pilots that they were right at the limit.

4.) The 109E had frequent problems with slat failure, being enough reason for even a German experten to choose not to push the 109 to the limit in turns because of their past experience with the Emil. The British test-pilots (if not having experienced troubles with the slats on the Emil and therefore being concerned when testing later versions) had themselves heard nothing but bad news about the slats, seeing that a few Westlands crashed because of slat failure and that this had led o hem being locked shut in flight, given more than enough reason for British pilots to be vary about the slats.

 

[Kurfürst]

Curious, it seems the manufacturer North American`s performance figures are always much higher than all the figures obtained elsewhere. I wonder why.

 

[FLYBOYJ]

Curious, it seems the manufacturer North American`s performance figures are always much higher than all the figures obtained elsewhere. I wonder why.

Because the aircraft used at the factory are pristine, probably polished bare metal and tested with minimum fuel on board.

The normal rule of thumb for any flight is to have at least 30 minutes of reserve fuel on board (that's actually a regulation for civilian aircraft). I once read that when many WW2 and post WW2 era aircraft went on speed runs they did so with minimum fuel, sometimes dead-sticking the aircraft because of fuel exhaustion.

6 pounds per gallon could add up to some excess weight......

I think this was depicted in the Howard Hughes movie when he was setting a speed record with his R-1.

 

[AL Schlageter]

Curious, it seems the manufacturer North American`s performance figures are always much higher than all the figures obtained elsewhere. I wonder why.

I did not know that

Army Air Forces Material Command
Flight Test Engineering Branch
Wright Field, Dayton, Ohio

was a manufacturer.

 

[Glider]

1.) The British test-pilot makes the comment: "The 109 being embarrased by the opening of its slots", this alone being a clear enough sign that he wasn't pushing past slat deployment.

I have a different understanding of the phrase 'the 109 being embarrased by the opening of its slots.

If you are flying in a tight turn on the edge of the stall then one wing is going more slowly than the other. As a result the slats will not open evenly, one will open before the other causing the aircraft to 'stagger' or 'lurch' to one side for a second.
In a tight turning dogfight this could easily give the opponent the advantage. Not in every case but in some depending on the tactical situation. This is a more logical definition of the phrase embarrased.

I have been part of a stack of gliders in a thermal, when one of them has overcooked it and I have had to take evasive action. Its suprising how quickly things happen even in a glider, the other machine almost seems to stop.

I am not saying that when both slats extend that the turn doesn't significantly improve, but there is that short but dangerous period when the aircraft is at significant risk.

Just a thought

 

[drgondog]

Kurfurst - the first production H's were delivered Feb 3, 1945.

The Experimental lightweight P-51F, 'father of the 51H', first flew on February 14, 1944. It was completely new design basically and weighed 5635 pounds empty. With the same engine as the P-51B at that time (1650-3) it had a top speed of 466mph at a Gross weight of 7265 pounds at 29,000 feet.. cruise speed of 380mph at 25,000 feet.. less than 5 minutes to 20,000 feet for climb.

This was with guns but only half load of fuel and no external rack. Max TO was 7630 pounds

In the flight tests the roll rates for 90 degrees were 1.6 ses, 2.0 sec and 2.6 sec at 300, 360 and 400 mph at 10,000 feet..

In order to boost the new airframe even more the forerunner of the 1650-11, the 14 S.M. engine, was installed as the X-p51G which had the most Hp -2000 at 80" at 20,000 feet and max speed at 495mph at 22,800 feet - service ceiling at 46,000 due to lack of pressurization (according to Gruenhagen' Mustang- Story of the P-51). He states that this ship attained 20,000 feet in 3.4 minutes but I am still looking for the actual data.

Points have been made that the P-51H never was in combat and should not be used in comparisons to Ta152 or Fw 190D-9, etc. I would pose the question.

Does anyone think that if the 51H was deemed critical to the war effort that it would not have been available in Oct-Dec 1944? The aircraft production contract for 2400 a/c was let in April 1944 (about the same time as Ta 152) but the XP-51F actually flew a couple of months before the Ta 152.

One of the sources I read stated that the Ta 152 was only tested 51 hours before first production version was delivered to the field in late October - is that true?

At any rate the P-51H was available in squadron strength in March and could have been deployed either to ETO or PTO if deemed necessary - but never was deployed over seas remaining USAAF and USAF front line interceptor until the P-80s replaced all the active duty squadrons.

When my father was CO of 35FBW in Occupied Japan - all the Mustangs were late model P-51D's mostly -25 and -30's.

I'll find the website (linked to Tony Woods) which has all the JG TO data i was referring to.

Regards,

Bill

 

[Kurfürst]

This seems relevant. An extreme coincident, too, the restored Black Six being the SAME airframe that was tested vs. Tempest, Mustang:

Flying Black 6 by Dave Southwood

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.

 

[drgondog]

Kurfurst - this is the Order Of Battle reference

Flugzeugbestand und Bewegungsmeldungen, Jagdverbände

Regards,

Bill

 

[drgondog]

Kurfurst - this is the Order Of Battle reference

Flugzeugbestand und Bewegungsmeldungen, Jagdverbände

Here is the NA test data on the rate of climb and climb rate. So, it appears Gruenhagen's reference to 3.4 minutes to 20,000 feet was not in error.

I did not realize the initial climb rate at SL was 6400 ft min and still doing 5700 fpm at 17500 and 470mph at 35,000 feet

http://www.wwiiaircraftperformance.org/mustang/xp-51g-chart.jpg

Regards,

Bill

Soren - you can complain about Mike's collection of test reports not conforming to your notions of the Fw 190D-9 or other LW a/c... but you should emulate Kurfurst and at least produce similar bona fide test data form LW to refute what you believe to be 'predjudice'??

 

[Crumpp]

If you are flying in a tight turn on the edge of the stall then one wing is going more slowly than the other. As a result the slats will not open evenly, one will open before the other causing the aircraft to 'stagger' or 'lurch' to one side for a second.

There is nothing bad aerodynamically about properly designed LE devices. They are mainstay of modern wing design.

Handley Page automatic slats deploy at a specific coefficient of lift. The wing deploys them "as needed". Handley Page automatic slats represent both a camber change and energize the boundry layer.

The pilots reaction to this is much more important to flight performance than the slat itself. My aircraft has them and yes, they took some getting used too. Once I conditioned my reactions though, the low speed performance with them deployed is fantastic. The effect is very noticable.

Yes the plane will lurch if the pilot does not react properly with appropriate inputs. That is not to say the slats are at fault. The pilot is at fault for not having the experience to use them. The slats definately will improve low speed performance. That is why most modern fighters have LE devices.

All the best,

Crumpp

 

[Glider]

There is nothing bad aerodynamically about properly designed LE devices. They are mainstay of modern wing design.

Handley Page automatic slats deploy at a specific coefficient of lift. The wing deploys them "as needed". Handley Page automatic slats represent both a camber change and energize the boundry layer.

The pilots reaction to this is much more important to flight performance than the slat itself. My aircraft has them and yes, they took some getting used too. Once I conditioned my reactions though, the low speed performance with them deployed is fantastic. The effect is very noticable.

Yes the plane will lurch if the pilot does not react properly with appropriate inputs. That is not to say the slats are at fault. The pilot is at fault for not having the experience to use them. The slats definately will improve low speed performance. That is why most modern fighters have LE devices.

All the best,

Crumpp

I am not saying that there are any problems with the design of the slats, they are doing exactly what they are designed to do.
What I would like to ask when the plane deploys one slat due to being in a tight high banked turn does it lose speed in that period before the second slat deploys?
I think you can see where I am coming from, if you are in a tight turning battle with an enemy close behind then any loss of momentum, no matter how slight could explain the comments in the reports.

 

[Crumpp]

I think you can see where I am coming from, if you are in a tight turning battle with an enemy close behind then any loss of momentum, no matter how slight could explain the comments in the reports.

I agree with you. If a pilot was not used to the rapid stick movements and loud bang of the slats deploying he would certainly loose some monentum.

What I would like to ask when the plane deploys one slat due to being in a tight high banked turn does it lose speed in that period before the second slat deploys?

Yes, it does lose some speed. Velocity as you know is the key component of turn performance.

More importantly, the usable angle of attack is increased further tightening the turn.

This is why experienced 109 pilots felt that the real maneuvering did not begin until the slats deployed.

All the best,

Crumpp