Author Topic: Fw 190A vs P-47D diving from 25,000 ft to deck.  (Read 13620 times)

Offline bozon

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Fw 190A vs P-47D diving from 25,000 ft to deck.
« Reply #30 on: April 27, 2007, 04:17:12 AM »
And yet 8th AF jug pilots considered diving away to escape from the jug, a futile attempt. I'll check Johnson's book again to see how many kills he got in a dive. I remember he commented on one of these kills: "They never learn".
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Offline Viking

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Fw 190A vs P-47D diving from 25,000 ft to deck.
« Reply #31 on: April 27, 2007, 04:29:19 AM »
If we get back to the initial debate; let’s look at the physics involved and set up an experiment.

Let’s say we have two planes: Plane A and plane B.

Plane A
Weight: 1000kg
Thrust: 1000kg

Plane B
Weight: 2000kg
Thrust: 1000kg

Both planes are otherwise identical (size, shape, drag).

Now … if both planes are lifted up to altitude by balloon and dropped at zero speed, we can ask two questions:

1. Which plane will accelerate quickest initially?

2. Which plane will achieve the greatest terminal velocity?

The answer to the first question is Plane A. Initial acceleration is determined by the thrust to weight ratio. Plane A gets 1G of acceleration from Earth’s gravity, and another 1G of acceleration from its thrust (being equal to its weight). Plane B also gets 1G acceleration from gravity, but only 0.5G from its engine thrust (being only half of its weight).

The answer to the second question is Plane B. As speed increase the thrust to weight ratio becomes secondary to the weight+thrust to drag ratio. Plane B has 2000kg of weight and 1000kg of thrust and will therefore stop accelerating at a speed where the total drag is equal to 3000kg. Plane A having only a total of 2000kg of weight and thrust will stop accelerating when drag is 2000kg.

This is of course very simplified. When we are comparing two different planes with different aerodynamics and propulsion systems it becomes very complicated. One interesting thing that the RAE people found out dive testing Spitfires was that of the speed they achieved only 1% was due to propeller thrust. 3% was from exhaust thrust, and the rest was due to gravity. With propeller driven planes the thrust does not remain constant at different speeds. The propeller loses efficiency as speed increases, and thus the weight to drag ratio of the plane becomes even more important.

So which plane dives better, the Fw 190 or the P-47? I don’t think there is an easy answer to that question.

Offline Viking

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Fw 190A vs P-47D diving from 25,000 ft to deck.
« Reply #32 on: April 27, 2007, 04:30:00 AM »
Quote
Originally posted by bozon
And yet 8th AF jug pilots considered diving away to escape from the jug, a futile attempt. I'll check Johnson's book again to see how many kills he got in a dive. I remember he commented on one of these kills: "They never learn".


Which model P-47 did he score his kills in?

Offline Widewing

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Fw 190A vs P-47D diving from 25,000 ft to deck.
« Reply #33 on: April 27, 2007, 06:38:46 AM »
Quote
Originally posted by Viking
The P-47D-30 was the first P-47 that could do that since among other structural improvements it had new blunt-nosed ailerons to improve controllability at high speeds, and to help in dive recovery at these high speeds, electrically-operated dive recovery flaps fitted on the undersurfaces of each wing. All P-47B, C and previous P-47D’s were deathtraps above Mach 0.73.

I could call you an idiot for not knowing that, but I won’t.

Eric M. Brown is undisputedly the world’s most experienced test pilot, and having flown all major types of allied and axis aircraft is in a unique position to comment on their relative performance. General Doolittle came to Farnborough to recruit the aid of RAE, and they specifically tested the P-38s and P-47 in service at that time (1943) against the captured 109s and 190s they had available. Calling this man an idiot is a grave insult and what respect I had for you is now gone.


Fisher's P-47 was specifically NOT fitted with the dive recovery flaps, nor was his P-47D-26-RA that he began the test program with. The D-26 was retired after cracks were discovered in engine A frame mountings. Dive recovery flaps generated too much drag and positive pitch-up. Fisher was testing transonic propellers and needed to exceed Mach 0.75, which the P-47 would not do with the recovery flaps deployed. Fisher used trim to initiate pull-out, just like every P-47 pilot was instructed to do.

I'll bet you think Yeager is another distinguished test pilot of great reputation too, right?

Brown has a long-time reputation within the Flight Test community of being a wind bag and has been frequently accused of misstatements. Many of his evaluations were diametrically opposed to those of other test pilots and his combat evaluation of the Fw 190D was literally laughed at Langley Field.

As it is, Brown's P-47 comments are not supported by the operational record, nor do they agree with many other test pilots who have vastly greater experience testing the Jug. Fewer P-47s were lost in dive related accidents than P-51s.

I came to the conclusion many, many years ago that Brown was not a reliable source for objective flight reports as he was remarkably opinionated and could not keep his personal opinion from contaminating his data. His feuds with fellow test pilots were well known and some persist to this very day.

Just because Brown says so, that doesn't make it true or accurate.

My regards,

Widewing
« Last Edit: April 27, 2007, 06:46:13 AM by Widewing »
My regards,

Widewing

YGBSM. Retired Member of Aces High Trainer Corps, Past President of the DFC, retired from flying as Tredlite.

Offline Charge

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Fw 190A vs P-47D diving from 25,000 ft to deck.
« Reply #34 on: April 27, 2007, 06:42:01 AM »
"Inasmuch as the Fw 190 uses the same wing section as the F4U (NACA 23015), I doubt that the 190 had a critical Mach greater than the P-47."

I'd say that the wing area, aspect ratio and planform design (sweep angle) are as relevant as wing profile as far as the thickness values stay at reasonable levels when critical mach is concerned. In fact the sweep angle helps in getting higher mach than would be possible with straight leading edge with given thickness ratio.

P47 300 sq ft
Inner: Seversky S-3, outer: Seversky S-3 (thickness ratio??)
FW190 197 sq ft
Inner: NACA 23015.3, outer:NACA 23009

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Offline Widewing

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Fw 190A vs P-47D diving from 25,000 ft to deck.
« Reply #35 on: April 27, 2007, 06:44:37 AM »
Quote
Originally posted by Viking
Which model P-47 did he score his kills in?


21 of his kills came in a P-47D-5, two more in a P-47C-5... Brown's death trap. His last kills were in a D-21, I believe:rolleyes:

I will reiterate: Brown is an idiot.

My regards,

Widewing
My regards,

Widewing

YGBSM. Retired Member of Aces High Trainer Corps, Past President of the DFC, retired from flying as Tredlite.

Offline BlauK

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Fw 190A vs P-47D diving from 25,000 ft to deck.
« Reply #36 on: April 27, 2007, 07:48:56 AM »
Quite arrogant of you to post such insults of an older gentleman on a public board.


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Offline Oldman731

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Fw 190A vs P-47D diving from 25,000 ft to deck.
« Reply #37 on: April 27, 2007, 08:19:18 AM »
Quote
Originally posted by BlauK
Quite arrogant of you to post such insults of an older gentleman on a public board.

Based on WW's research and interviews, I'm not sure you could consider them insults.

Thanks for the information, WW, very informative as usual.

- oldman

Offline Charge

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Fw 190A vs P-47D diving from 25,000 ft to deck.
« Reply #38 on: April 27, 2007, 08:58:02 AM »
Well, Kurfy once called Carson an idiot and eventually got booted. Any bets? :D

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"When you wish upon a falling star, your dreams can come true. Unless it's really a giant meteor hurtling to the earth which will destroy all life. Then you're pretty much screwed no matter what you wish for. Unless of course, it's death by meteorite."

Offline Stoney74

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Fw 190A vs P-47D diving from 25,000 ft to deck.
« Reply #39 on: April 27, 2007, 09:01:15 AM »
Quote
Originally posted by Viking
Early B and C model P-47s could also simply disintegrate in mid air.


Reference???
« Last Edit: April 27, 2007, 09:09:19 AM by Stoney74 »

Offline Viking

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Fw 190A vs P-47D diving from 25,000 ft to deck.
« Reply #40 on: April 27, 2007, 09:15:47 AM »
“Two days later, as I lay on my bunk listening to the King Cole Trio, my reverie was rudely interrupted by a loud, eerie, whining drone. Suddenly, a loud thud punctuated the drone, followed by stark silence. I knew one of our planes had gone down. I prayed that the pilot had bailed out. I ran outside and climbed into my Jeep, along with a couple of fellow pilots. We could see the tell-tale plume of black smoke rising swiftly into the beautiful, sun-drenched sky. The beautiful sky gave us hope that our friend might be alright. As I plunged through the woods and rough terrain, it was impossible to see if a parachute was floating down. We finally reached a clearing in a clearing made by the Jug. Fallen trees, tree limbs, and loose dirt surrounded a crater in the earth twenty-odd feet deep and fifty-odd feet across. The plane had dived into the ground nose first and vertically!”

 William M. Wheeler
Tuskegee Airman
332nd Fighter Group
302nd Fighter Squadron


“I was interested in evaluating three developments now in the P-47M. It had the new 360-degree-vision bubble canopy; it could climb to 40,000 feet without stopping to "rest" above 30,000 feet; and it had dive-recovery flaps to cure its former uncontrollable compressibility diving with no recovery possibility.”

Corky Meyer
Test pilot


“Gradually, the Group learned how to manage the Thunderbolt. Still, there was a new problem beginning to appear. Powerful fighters such as the P-47 and P-38 were encountering something relatively new to aviation; compressibility. This new generation of high-speed aircraft were capable of incredible speeds in a dive. Compressibility is a term used to describe what happens when localized airflow across a wing approaches transonic velocity. The resulting shock wave could lock the elevators as if in a vise. Pilots were running up against compressibility and they were dying. P-47’s and P-38’s were being flown straight into the ground, or even breaking up in flight. The learning curve was far steeper than it had ever been before. Pilots now had to learn how to deal with this new, terrifying phenomena. Testing showed that the Thunderbolt could be flown out of a terminal velocity dive as it descended into warmer air at lower altitudes. This is because as the plane continues down, the relative speed of sound goes up. Eventually, the aircraft’s Mach number will drop (although its actual airspeed does not) and the shock wave will dissipate, allowing the pilot to regain control again. Pilots were instructed to pull off the throttle, and avoid using too much up elevator trim. Too much trim, or too much back pressure on the stick could over-stress the airframe when the fighter began to respond to control inputs. Pilots who had flown the P-47 into compressibility came away with bruises to verify their adventure. The Thunderbolt’s ailerons would flutter as it exceeded its critical Mach limits, causing the stick to move violently from side to side; pummeling the inside of the pilot’s thighs black and blue.”

Warren M. Bodie, by the pen of Corey C. Jordan.

----

P-47C Thunderbolt 41-6628 of the 495th Fighter Training Group USAAF crashed at Thorncliffe on the 3rd October 1944.

Crew / Passengers
 Rank - if applicable
 Service Number  Position e.g. Pilot
 Status
 
Quentin J Sella
 2nd Lieutenant
 O-710189  Pilot
 Killed
 
Above is a photograph of Quentin J. Sella shortly after receiving his commission in February 1944, this appeared with his obituary in the Grand Rapids Press (one of the newspapers from the city he was from in Michigan) on the 30th October 1944. He had joined the USAAF as an officer cadet in 1942 being commissioned in early 1944.  From April to September he served with the 33rd Fighter Squadron in Iceland, in June he was involved in a minor ground accident when the P-47 he was in ground looped when one brake failed.  He arrived in England only a month before he was killed.

Mark stood by where the P-47 dived into the ground, being a natural spring the ground is very soft.

The aircraft had been flying as part of a 4 ship formation on a formation flying exercise, this aircraft was in the number 4 position. On entering cloud the formation became split up with the number 1 and 3 aircraft staying together and number 2 and 4 becoming separated. They were directed onto diverging courses by the flight leader to avoid the possibility of midair collisions. In the crash report it is assumed that 2nd Lt Sella became disorientated as his instruments may have been giving false reading. Because of this he lost control and the aircraft entered either a dive or spin, the aircraft fell into the ground in a vertical dive hitting very soft ground and deeply burying itself.

This photo showed the aircrafts canopy which had been jettisoned and fell some 400 yards from the crash site, 2nd Lt Sella obviously tried to bale out of his aircraft but due to the high-speed dive would have been unable to exit the cockpit due to the slipstream.

This photo shows the seen at the crash site, all that can be seen is the massive hole filled with mud and water.

----

Quote
Originally posted by Widewing
I will reiterate: Brown is an idiot.


Brown is not, but you clearly are.

Offline TUXC

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Fw 190A vs P-47D diving from 25,000 ft to deck.
« Reply #41 on: April 27, 2007, 09:43:08 AM »
Dive flaps have been mentioned a few times so far. The P-47D-40 has them, but the P-47N we have doesn't seem to have them. Why is this?
Tuxc123

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Offline BlauK

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Fw 190A vs P-47D diving from 25,000 ft to deck.
« Reply #42 on: April 27, 2007, 09:44:33 AM »
Quote
Originally posted by Oldman731
Based on WW's research and interviews, I'm not sure you could consider them insults.
 



I suppose I can also call you one without it being an insult, because I disagree with you but I have worked as a researcher for several years?


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Offline Oldman731

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Fw 190A vs P-47D diving from 25,000 ft to deck.
« Reply #43 on: April 27, 2007, 10:14:05 AM »
Quote
Originally posted by BlauK
I suppose I can also call you one without it being an insult, because I disagree with you but I have worked as a researcher for several years?

Truth is a defense, dude.  If I were making things up and telling you they were real, particularly if they were things that I should expect other people to rely on, you might justifiably call me an idiot when you found out about it.  My age, experience and rugged good looks don't really enter into the analysis.

- oldman (btw, you would not be the first to call me an idiot, either!)

Offline TimRas

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Fw 190A vs P-47D diving from 25,000 ft to deck.
« Reply #44 on: April 27, 2007, 10:38:36 AM »
From Wikipedia:

Captain Eric Melrose "Winkle" Brown, CBE, DSC, AFC, FRAeS, RN is a former Royal Navy officer and test pilot who has flown more types of aircraft than anyone else in history. He is also the Fleet Air Arm’s most decorated pilot.,
Born in January 1919, he first flew when he was 18.

After World War II‚ Brown commanded Enemy Aircraft Flight, an elite group of pilots who test-flew captured German aircraft. That experience makes Brown one of the few men qualified to compare both Allied and Axis "warbirds" as they actually flew during the war. He flight-tested 53 German aircraft, including the Me 163 rocket plane and the Messerschmitt Me 262 jet plane.

On December 3, 1945, Brown made the world's first landing of a jet aircraft on an aircraft carrier. He landed a de Havilland Sea Vampire on the Royal Navy carrier HMS Ocean.

He flew aircraft from Britain, America, Germany, Italy and Japan, and is listed in the Guinness Book of World Records as holding the record for flying the greatest number of different aircraft. The official record is 487, but only includes basic types. For example Captain Brown flew several versions of the Spitfire and Seafire, and although these versions are very different they only appear once in the list.

He was the first to land a jet aircraft on a carrier, and also holds the world's record for the most carrier landings, 2,407.

He finally gave up his wings at 70 years old, but still lectures. He is a regular attendee of British Rocketry Oral History Programme (BROHP).



As we can all see he must have been a complete idiot (and British, a damn foreigner at that).

And then we have a real smart guy, who takes a three year old in the cockpit  and dives an airplane to its limits testing experimental propellers, because only idiots would think that something could go wrong. But real pilots know that is NOT possible.