F4U Turning surprise

[Widewing]

Didn't the F8F also have the wing shape of a FW 190?

The 190D-9 had NACA 23015.3 at the root, and NACA 23009 at the tip.

The F6F-5 had NACA 23015.6 at the root, and NACA 23009 at the tip.

Very nearly identical...

The F8F-1 had NACA 23018 at the root and NACA 23009 at the tip.

A bit less like the 190....

[BnZs]

Maybe it is just me, but when fighting skilled Dora pilots in a P-51, it seems like they can often "get on top" and put me on the defensive after a few turns. Skyyr is good at this, from a co-alt merge. Of course the F6F is superior to the P-51 in wing loading and presumably energy retention in turns, so that may be the difference.

If You have equally skilled pilots, a Co-E engagement in the MA can result in tactical draw.

So, you have gauge the relative skill of the opposition. However, inasmuch as the initial tactical situation has almost limitless variation, one cannot paint with a broad brush. In dueling, with the tactical limits, there isn't much the better power loading fighter can do, but hope for an error. In the case of the Dora vs F6F in the MA, the Dora driver can always disengage and go looking for a less difficult challenge. They often do just that..  

[Widewing]

Maybe it is just me, but when fighting skilled Dora pilots in a P-51, it seems like they can often "get on top" and put me on the defensive after a few turns. Skyyr is good at this, from a co-alt merge. Of course the F6F is superior to the P-51 in wing loading and presumably energy retention in turns, so that may be the difference.

I've had several 1v1 fights with Dora's in the MA, piloted by guys who fly it almost exclusively. In every case I can recall, the Dora had a big altitude advantage at the outset. So, I started with the disadvantage. Inasmuch as I rarely fly very high, and generally fly in defense, I've developed methods of dealing with this situation. One doesn't have to burn much E to avoid the Dora. I can easily induce an overshoot, and I have become adept at scoring hits when they do so. I don't waste E. Sooner or later, the other guy will make a mistake, or simply leave or change to a less annoying target. If I go through the last 3 years of tour data, I doubt that I'll find a single instance when I lost an F6F to a 190D-9.

[save]

Save, why wouldn't a P-51D dive as fast as a P-51B?

I remember reading this some p51d pilot accounts of this somewhere, it was due to the razorback gave  better stability at high speed than the p51d, where the bubble canopy disturbed the airflow over the tail.

here I found one source :

On two other occasions ME 109s got away from me because the P 51d could not stay with them in a high-speed dive. At 525-550 mph the plane would start to porpoise uncontrollably and had to be slowed to regain control. The P 51 was redlined at 505 mph, meaning that this speed should not be exceeded. But when chasing 109s or 190s in a dive from 25-26,000 it often was exceeded, if you wanted to keep up with those enemy planes. The P 51b, and c, could stay with those planes in a dive. The P 51d had a thicker wing and a bubble canopy which changed the airflow and brought on compressibility at lower speeds."
- Robert C.Curtis, American P-51 pilot.

dive test :
http://www.wwiiaircraftperformance.org/mustang/mustangIV-divetest.html

[danny76]

I remember reading this some p51d pilot accounts of this somewhere, it was due to the razorback gave  better stability at high speed than the p51d, where the bubble canopy disturbed the airflow over the tail.

here I found one source :

On two other occasions ME 109s got away from me because the P 51d could not stay with them in a high-speed dive. At 525-550 mph the plane would start to porpoise uncontrollably and had to be slowed to regain control. The P 51 was redlined at 505 mph, meaning that this speed should not be exceeded. But when chasing 109s or 190s in a dive from 25-26,000 it often was exceeded, if you wanted to keep up with those enemy planes. The P 51b, and c, could stay with those planes in a dive. The P 51d had a thicker wing and a bubble canopy which changed the airflow and brought on compressibility at lower speeds."
- Robert C.Curtis, American P-51 pilot.

Those 109's were probably en route to a spectacular lawn dart if my experience of gaming in them is anything to go by

[save]

double

[Widewing]

I remember reading this some p51d pilot accounts of this somewhere, it was due to the razorback gave  better stability at high speed than the p51d, where the bubble canopy disturbed the airflow over the tail.

here I found one source :

On two other occasions ME 109s got away from me because the P 51d could not stay with them in a high-speed dive. At 525-550 mph the plane would start to porpoise uncontrollably and had to be slowed to regain control. The P 51 was redlined at 505 mph, meaning that this speed should not be exceeded. But when chasing 109s or 190s in a dive from 25-26,000 it often was exceeded, if you wanted to keep up with those enemy planes. The P 51b, and c, could stay with those planes in a dive. The P 51d had a thicker wing and a bubble canopy which changed the airflow and brought on compressibility at lower speeds."
- Robert C.Curtis, American P-51 pilot.

dive test :
http://www.wwiiaircraftperformance.org/mustang/mustangIV-divetest.html

Curtiss was wrong. There is no difference in the wing thickness between the P-51B and P-51D. Pure myth, quoted by many since. Instability along the flight axis was restored with the dorsal strike added to the rudder transition. The wing profile and thickness ratio is identical. All P-51s had the same critical Mach, which was considerably higher than that of the Bf-109.

[GScholz]

Critical mach does not limit top dive speed, only controllability. The 109 lost effectiveness of its main control surfaces earlier than the P-51 in a dive, but the elevator trim in the 109 and 190 remained effective at any speed allowing recovery from a dive at any time. Even at extreme beyond-red-line speeds approaching 600 mph, as one Finnish pilot found out. The 109 would also not tuck-under like the P-38 and P-47 when approaching critical mach, but had to be trimmed nose down to stay in a dive. Otherwise it would level off on its own. The p-51 was not as sturdy in a dive as the P-38 and P-47. Several pilots lost their lives in dives after converting to the P-51 from P-47s.

[Widewing]

Critical mach does not limit top dive speed, only controllability. The 109 lost effectiveness of its main control surfaces earlier than the P-51 in a dive, but the elevator trim in the 109 and 190 remained effective at any speed allowing recovery from a dive at any time. Even at extreme beyond-red-line speeds approaching 600 mph, as one Finnish pilot found out. The 109 would also not tuck-under like the P-38 and P-47 when approaching critical mach, but had to be trimmed nose down to stay in a dive. Otherwise it would level off on its own. The p-51 was not as sturdy in a dive as the P-38 and P-47. Several pilots lost their lives in dives after converting to the P-51 from P-47s.

Critical Mach reflects the onset of compressibility, above that controllability can rapidly deteriorate. P-38s and P-47s did not encounter Mach Tuck until well beyond critical Mach.

[GScholz]

Glad we agree. Like I said critical mach does not limit top dive speed... only controllability.  Btw. That chart was made post-war by an RAF officer for a magazine article... And if I recall correctly it reflects the relative differences in dive acceleration. Weight would be the biggest factor and we can see that the aircraft are sorted by weight as well with the 109 being the lightest and the Meteor the heaviest. We all know that the Spitfire was the fastest diver of the piston engines fighters (and had the highest critical mach number), but in that chart it is way back with the Jerries. The fastest known (and survived) dive speed of a WWII prop fighter was achieved by S/Lr Martindale, in a Spitfire P.R.XI, with a speed of 606mph (Mach .89) before his engine exploded, and the propeller disappeared. He landed safely. Finnish ace Valte Estama dived his damaged 109G-6 to 590 mph to put out an engine fire. He landed safely with the aircraft intact.

[Widewing]

Glad we agree. Like I said critical mach does not limit top dive speed... only controllability.  Btw. That chart was made post-war by an RAF officer for a magazine article... And if I recall correctly it reflects the relative differences in dive acceleration. Weight would be the biggest factor and we can see that the aircraft are sorted by weight as well with the 109 being the lightest and the Meteor the heaviest. We all know that the Spitfire was the fastest diver of the piston engines fighters (and had the highest critical mach number), but in that chart it is way back with the Jerries. The fastest known (and survived) dive speed of a WWII prop fighter was achieved by S/Lr Martindale, in a Spitfire P.R.XI, with a speed of 606mph (Mach .89) before his engine exploded, and the propeller disappeared. He landed safely. Finnish ace Valte Estama dived his damaged 109G-6 to 590 mph to put out an engine fire. He landed safely with the aircraft intact.

The fastest documented dive speed for a P-47 was Mach 0.83, flown by  Herb Fisher. This P-47 was equipped with a Mach meter and data recorders.

Fisher, a test pilot for Curtiss Wright, was testing supposedly transonic propellers using a borrowed Air National Guard P-47D-30. This Thunderbolt was fitted with Dive Recovery Flaps. The P-47, having been subjected to the stresses of  over 200 terminal speed dive, was returned to the Air Guard, where it was flown until 1954, when it (and the others) were replaced by the Republic F-84. It takes a stout airframe to shake off that much abuse.

During the test program, Fisher made over 200 dives at speeds at or in excess of Mach 0.79 . His fastest dives attained were Mach 0.83 with the recovery flaps deployed. During these dives, Fisher suffered bruising to the inside of his thighs due to the stick violently oscillating side to side. His wife made and sewed on padding to his flight suit legs to protect him from the stick beating his legs black and blue.

As a side note, Fisher took his 3 year-old son on one of those dives. Herb Fisher Jr. was the fastest toddler on earth until Jet airliners made their passenger debut. Herb Jr. sent me scans of photos documenting the event. Yes, they had to fabricate an oxygen mask for the child. These days, you would go to jail for that stunt….

As to Martindale, I believe his Spitfire accelerated to Mach .89 AFTER the prop shaft failed. The engine certainly was over-sped, which was a common issue with high Mach dives. The prop governor cannot limit the RPM. Many engines were replaced due to running the engine several hundred RPM beyond the allowable maximum resulting from  dives.

[save]

I do not challenge the p47 ability to dive, in fact in aces high p47 have a hard time catching diving 190a's which they should not have.

I have read more pilot reports about the 51d not be able to dive with 109g if the 109g could reach his max speed before the p51 could catch him.
Many times the 109 where shot down well before reaching max speed though, remember also when the p51d where introduced, 90% of German pilots where newbies.

[GScholz]

Yes the Thunderbolt was a very sturdy design indeed. No Save, the P-47 does not have any problems catching a 190 in a dive as long as the dive is done historically: P-47 dives from its perch several thousand feet above the 190, which is busy gunning for a bomber. When it is almost in gun range the 190 pilot spots the 47 coming screaming down and starts his dive. P-47 catches up quick and kills the 190.

[save]

If both start diving at 300mph 190 accelerate a bit faster initially like RL, but then  7 ton of liberty should catch up, but it looks from my experience like the 47 have a hard time catching up.

190a8 can dive to 620 mph trembling and shaking the last 20mph in AH, and do a gentle pull up,  i have never seen a p47 do that, it might be possible but it has been my lifesaver quite some times in AH.

[GScholz]

190 has a greater top speed in a dive than the P-47. The P-47 has greater zero-G pushover dive acceleration. It's important that you don't over-G the entry of the dive or you'll just bleed away the advantage and the 190 gets away. The differences in dive performance are not really that significant and the plane that enters the dive first with more initial speed generally wins.