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General Category => General Discussion => Topic started by: redrider90 on May 06, 2016, 09:38:02 PM
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spitfire 0.92 with no propeller
http://www.bbc.com/future/story/20160505-the-spitfires-that-nearly-broke-the-sound-barrier
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Interesting read
One lucky bunny to make it back alive
Thanks
John
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The early pre-production Reggiane Re.2005, due to the scarce quality of "autarchic" aluminium alloys used in their construction, showed some "aeroelastic" problems during aerobatic manuvers at high speed. For that reason the tail section was redesigned for the standard production aircraft, and all of the pre-productions were sent back to the Officine Reggiane to reinforce the tail section.
Com. Tulio De Prato, test pilot of the Officine Reggiane, tested the first modified Re.2005, to see if the changes had been effective.
He signed this picture of the aircraft he used, with the speed he reached in dive.
(http://www.aldini.it/re2005/980km-h1.JPG)
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Walker of dogs (poodles approve),
Incredible machines and pilots, indeed! My dad (76th General Field Hospital, US Medical Corp, European Theatre) watched a lot of dogfights during the war. He said the troops could identify fighter aircraft simply from the engine sounds. One day though, came a whispering sort of new aircraft. It was the new German twin jet fighter. They were pretty damn impressed. His middle brother was a B-17 Captain with the Mighty Eighth based in England. The jets were chasing the formations later in the war. One wonders if the ME-262 had more development time, testing, and tactics refinement, and numbers what impact on the air war would have happened.
https://en.wikipedia.org/wiki/Messerschmitt_Me_262
The dreaded V-1s with their humpahumpahumpa were feared when the engines cut out and dropped their explosives at random. He was almost "blown to bits" by one that hit the next door operations tent where he had just exited. The V-2s were worse: no warning, ballistic missiles hitting straight down, no warning.
Aircraft sounds are wonderful. Saw a couple old WW II birds circling here a couple weeks back, probably on their way back to Galveston.
Yeah, dad remembered the sounds. I have a picture of dogfight contrails over Belgium.
thanks!
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Good story about the spit.
The P51 had a much cleaner and better critical mach capable airfoil (66 series laminar airfoil) than any of the other fighters of the time.
After WWII in testing a P51 without a prop (with spinner) was towed by a P61 black widow to over 30,000 feet and dropped with a pilot
and reached a high sub mach number .97 as I recall. (at some point the prop becomes more drag than thrust (over simplified.)
For that feat it was awarded by congress as the cleanest aerodynamic aircraft of the war.
:-)
edit:
I remember reading about the test on the P51B towed to altitude by the P61 at the Caltech engineering library but the sub mach number part I can not verify as .97. I'm sure it was quite high 'cause the mustang was more aerodynamically cleaner than a spit. (laminar airfoil in part).
.97 was most likely not right.
Boggles my mind that someone was brave enough to do that!!!!!
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It took some guys with serious cajones to be delving into unknown territory like that.
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The Hawker Tempest and the Fock Wulf 152TA weren't
too bad either.
Maurie.
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My father was a bombardier in the nose of a B-17 during WW II in Europe. He said those ME 262s went by their gunners so fast the gunners couldn't even get a bead on them. I have the map of his bombing missions over Europe.
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The BBC article made me wince. The author has a very shaky notion of transonics and propeller function. In particular, he's got no clue about the Merlin engine's reduction gearing (.48 in the Spitfire, .42 in other a/c including the Mustang), or how a variable-pitch prop works. So the explanations as to why props ripped off are kind of gee-whizzy inadequate.
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Read an account years ago of a Spitfire pilot who shot down the first (I believe) ME 262. It had been damaged and was ground hugging; the Spitfire saw him from on high and dived. Fired a burst before pulling up and happened to hit the 262, which crashed. He made it down but the plane was a right off. Speed was off the dial and it evidently exhibited all of the damage characteristics mentioned in that article.
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Read an account years ago of a Spitfire pilot who shot down the first (I believe) ME 262. It had been damaged and was ground hugging; the Spitfire saw him from on high and dived. Fired a burst before pulling up and happened to hit the 262, which crashed. He made it down but the plane was a right off. Speed was off the dial and it evidently exhibited all of the damage characteristics mentioned in that article.
I read an account of that as a kid in a book called
"The Big Show" by Pierre Closterman of 122 Squadron,
He was talking about the introduction of the Tempest -
and that the Spitty that shot the ME262 down had reached
Subsonic speeds and came back with twisted wings and
rivets popped - barely flyable. I think he saw the Spitty if I
remember it right, he was between tours, working in admin
as a break from flying ops and about to retrain on Typhoons
and Tempests.
Maurie.
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What speeds were those P-38s getting up to when they would get in serious aerodynamic trouble in dives over Europe?
Todd.
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P-38 mach tuck from Wikipedia. Mach .65 computes to 400mph true airspeed at 20,000 feet. (The problem was largely resolved by providing drag flaps under the wing center section and by making the cockpit nacelle a bit longer and more finely tapered.)
The fastest World War II fighters were the first aircraft to experience Mach tuck. Their wings were not designed to counter Mach tuck because research on supersonic airfoils was just beginning; areas of supersonic flow, together with shock waves and flow separation,[8] were present on the wing. This condition was known at the time as compressibility burble and was known to exist on propeller tips at high aircraft speeds.[9] The P-38 was the first 400 mph fighter, and it suffered more than the usual teething troubles.[10] It had a thick, high-lift wing, distinctive twin booms and a single, central nacelle containing the cockpit and armament. It quickly accelerated to terminal velocity in a dive. The short stubby fuselage had a detrimental effect in reducing the critical Mach number of the 15% thick wing center section with high velocities over the canopy adding to those on the upper surface of the wing.[11] Mach tuck occurred at speeds above Mach 0.65;[12] the air flow over the wing center section became transonic, causing a loss of lift. The resultant change in downwash at the tail caused a nose-down pitching moment and the dive to steepen (Mach tuck). The aircraft was very stable in this condition[12] making recovery from the dive very difficult. Dive recovery (auxiliary)[13] flaps were added to the underside of the wing (P-38J-LO) to increase the wing lift and downwash at the tail to allow recovery from transonic dives.
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Found this thread on WW2 fighter critical Mach numbers:
https://ww2aircraft.net/forum/threads/ww2-fighter-and-critical-mach-speed.802/
Me-163A: 0.845 (calculation DFS)
Me-163B: 0,84 (calculation A. Lippsch)
Me-262A : 0.86 (calculations of W. Messerschmidt)
Gloster Meteor: 0.83
Bell X-1: 0.88
pitfir MK IVX: 0.89*
Hawker Tempest: 0.83*
F4U: 0.73 (windtunnel tested)
P-51B: 0.84*
P-38: 0.65
P-47C: 0.69
P-47N: 0.83*
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Testarossa and Steph's posts clear up a story I heard years ago.
I was at the Centennial of Flight celebration at Kitty Hawk in 2003. I was only knee high to a horse then but old enough to know that the F4U Corsair was the coolest f***ing thing in the air (an admittedly subjective opinion but I'll argue it all day). I was standing by a Corsair there and met an old gent who had flown them in the war, I believe with the Jolly Rogers. He told me that he had gone supersonic in one. As the story goes, the sonic boom did a LOT of damage to the plane, ripping half the tail off, and he barely limped home.
Now as badass as the Corsair was I always found this story somewhat dubious. However, it would seem from the last two posts in this thread that likely he achieved a critical speed and Mach tuck. But I am not an aero engineer so I won't say for sure.
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He told me that he had gone supersonic in one. As the story goes, the sonic boom did a LOT of damage to the plane, ripping half the tail off, and he barely limped home.
Bear in mind that the Corsair had fabric control surfaces! Not surprised that the canvas might depart at transonic speed. The immediate increase in drag might have saved the pilot's life.
The Corsair design is an interesting case. At this point, piston engine power (P&W R2800) had reached about 2000hp and propellers had to grow accordingly. The Corsair eventually used a 13-foot prop. For ground clearance it would have needed really long spindly landing gear legs, deemed unsuitable for carrier landings. So the wing was cranked downward to keep the gear legs short.
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I read an account of that as a kid in a book called
"The Big Show" by Pierre Closterman of 122 Squadron,
He was talking about the introduction of the Tempest -
and that the Spitty that shot the ME262 down had reached
Subsonic speeds and came back with twisted wings and
rivets popped - barely flyable. I think he saw the Spitty if I
remember it right, he was between tours, working in admin
as a break from flying ops and about to retrain on Typhoons
and Tempests.
Maurie.
That's the one.
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Bear in mind that the Corsair had fabric control surfaces! Not surprised that the canvas might depart at transonic speed. The immediate increase in drag might have saved the pilot's life.
The Corsair design is an interesting case. At this point, piston engine power (P&W R2800) had reached about 2000hp and propellers had to grow accordingly. The Corsair eventually used a 13-foot prop. For ground clearance it would have needed really long spindly landing gear legs, deemed unsuitable for carrier landings. So the wing was cranked downward to keep the gear legs short.
I believe all the WW2 combat fighters when manufactured had some or all control surfaces covered in fabric.
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One wonders if the ME-262 had more development time, testing, and tactics refinement, and numbers what impact on the air war
Actually, if I remember it right they had too much development
time! "The Big Show" mentioned that the ME262 was demonstrated
to Hitler as a fighter. He thought it should be a Fighter Bomber
and insisted on a redesign which failed dismally. They then
re-instituted the original design. They lost 6 months or more
in getting it into combat and lost the advantage to a large
Degree.
Maurie.
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I believe all the WW2 combat fighters when manufactured had some or all control surfaces covered in fabric.
Generally true, but Mustangs had aluminum-covered ailerons and flaps from the beginning. Elevators were changed to aluminum sometime around the transition from C to D models. Rudders were fabric at first, but some were changed to aluminum and late models (H series?) were aluminum. See these photos of a P51D: http://www.ipmsstockholm.org/magazine/2005/12/stuff_eng_detail_p51d_02.htm (http://www.ipmsstockholm.org/magazine/2005/12/stuff_eng_detail_p51d_02.htm)
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Testarossa, that's why I love it. The muscle car of fighter planes. Everything about the design is to support this insanely massive motor.
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The muscle car of fighter planes. Everything about the design is to support this insanely massive motor.
Hellcat used the same engine. Thunderbolt used the same engine with a turbocharger. 2800 hp.
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Hellcat used the same engine. Thunderbolt used the same engine with a turbocharger. 2800 hp.
The real peculiarity of the Corsair is that it's the only US fighter that really took advantage of the relatively small frontal area of the P&W R2800.
US fighers tended to be on the "Big & heavy" side. The fuselage of both the Hellcat and the Thunderbolt, could have accomodated an even bigger engine, while the Corsair's fuselage was really hidden behind the P&W R2800.
(http://www.wingsovereurope.com/ww%202%20usa%20fighters%201/Corsair%20F-4%20F-AZEG%20LFFQ%202010%20(2).JPG)
(http://www.williammaloney.com/aviation/NewEnglandAirMuseum/GrummanF6FHellcat/images/01GrummanF6FHellcat.jpg)
A similar aircraft in this respect was the Lavochkin La-7.
(http://cdn-www.airliners.net/aviation-photos/photos/7/3/8/1711837.jpg)
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Got to love the Corsair design. One of my first bosses in the oil industry flew Corsairs in the Pacific. Hell of a guy, now passed: Captain Maxmillian W. Dix. Hero of mine.
Thanks for the info on airfoil design and Mach turbulence, very interesting.
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The real peculiarity of the Corsair is that it's the only US fighter that really took advantage of the relatively small frontal area of the P&W R2800.
That's a really good point. It strikes me that the most gorgeous airplanes were all designed on this principle. Think of the Mustang and Spitfire, which hid behind the Merlin, and the Tempest, which managed the same trick with a variety of engines. That Lavochkin is a great-looking plane too. I have a soft spot for the Yak 3.
(http://thumb.ibb.co/k4qiTv/LMA_MG_5923.jpg) (http://ibb.co/k4qiTv)
(http://thumb.ibb.co/dNpMFa/472_copy.jpg) (http://ibb.co/dNpMFa)
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That's a really good point. It strikes me that the most gorgeous airplanes were all designed on this principle. Think of the Mustang and Spitfire, which hid behind the Merlin, and the Tempest, which managed the same trick with a variety of engines.
Less widely known, but same principle brought to the extreme, the Ambrosini SAI 207/403
(http://www.finn.it/regia/immagini/ambro/ambrosini_sai_207_01.jpg)
(http://www.airwar.ru/image/idop/fww2/sai403/sai403-1.jpg)
That Lavochkin is a great-looking plane too. I have a soft spot for the Yak 3.
(http://thumb.ibb.co/k4qiTv/LMA_MG_5923.jpg) (http://ibb.co/k4qiTv)
(http://thumb.ibb.co/dNpMFa/472_copy.jpg) (http://ibb.co/dNpMFa)
I for the Mig-3, gorgeous aircraft, unfortunately designed for the wrong war (high altitude, long range figher on the eastern front).
(http://mig3.sovietwarplanes.com/mig3/fotobiancr.jpg)
(http://cdn-www.airliners.net/aviation-photos/photos/8/7/7/1970778.jpg)
(http://forum.il2sturmovik.com/uploads/monthly_08_2015/post-30291-0-47128600-1440444389.jpg)
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The goodyear F2G had a 4360 ci P&W (1945)
4 row radial, many were raced after the war by Cook Cleland, naval aviator!! (only 400 or so were built.)
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Hellcat used the same engine. Thunderbolt used the same engine with a turbocharger. 2800 hp.
That's why I found it so hilarious that people think the Dodge Challenger Hellcat was named after the plane. Naming their first boosted range topping Hemi after... a NA plane whose great advantage was simplicity and reliability?! I think not.
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The goodyear F2G had a 4360 ci P&W (1945)
4 row radial, many were raced after the war by Cook Cleland, naval aviator!! (only 400 or so were built.)
Actually, only 10 were built. Despite making 3000hp, the Super Corsair was slower than the Bearcat -- the Grumman was 30% lighter but could carry a bigger combat load on 2300 hp. It became the standard shipboard fighter until the jets came in.
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The Pratt and Whitney R2800 was one hell of an engine and considered to be the the best in the 2000 HP class . About 125,000 were made. Besides the fighters it was used in many US twin engine combat aircraft....There are supposedly true stories of P-47's taking flak and cannon fire to the engine blowing away a cylinder and the R2800 continued to run and make it home.
Imagine riding your Guzzi when 20 MM shells shoot off a cylinder and you continue to ride on spraying oil and sparks...
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Where are the boys in their coats of blue
Who flew when their eyes were blind
From Protocol by Gordon Lightfoot.