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DaveKamp 
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 Topic: Happy Kelly Johnson Day!
Posted: 27 Feb 2020 at 5:43pm |
Hey Everybody-
Happy Kelly Johnson Day!
If he didn't build something that saved your life, he probably built something that saved your father's, or your grandfather's.
"That Damned Swede can actually SEE AIR..."
Edited by DaveKamp - 27 Feb 2020 at 5:44pm
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Ten Amendments, Ten Commandments, and one Golden Rule solve most every problem. Citrus hand-cleaner with Pumice does the rest.
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klinemar
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Posted: 27 Feb 2020 at 7:41pm |
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Kelly Johnson was one of the best Aeronautical Engineers America has produced! Everytime a P38 shows up at the Thunder Over Michigan Air Show I try and make it. P47 and P51's make a lot of noise but a P38 is smooth sounding! Kelly went on and designed our first operational jet fighter the P80 and then the F105 Starfighter and SR71 Blackbird Reconnaissance plane that still holds speed and altitude records!
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desertjoe
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Posted: 27 Feb 2020 at 10:16pm |
Well,,Chit,,Dave,,,LOL,,,,and here i was thinkin them dang Rooskies had compromised my phone when I got your Text this mornin,,,,LOL,,,I deleted it "Before Quick Could Get Ready" ,,,,,then it hit me,,,I says,,,Chit I know that name!!!! but was too late. I did not know bout ole Kelly Johnson,,but I'm sure YOU did bein an engineer,,,  He did the SR71 Blackbird,,huh,,,,
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DaveKamp
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Posted: 28 Feb 2020 at 7:14am |
He was hired on as a tool boy, and his first aeronautical demonstration was correction of the Model 10 Electra - it was originally designed with a single tail, he noted to his superiors that it had directional stability issues, and demonstrated his skill by changing it to a 'twin tail' design (that placed the vertical stabilizers in the direct path of the Electra's twin propellers, rather than in the wash of the cockpit bulge's trail of turbulence).
He developed the P38- twin engine, twin fusealge, twin tail... turbo-supercharged, and first aircraft to exceed 400mph in level flight... versatile, fast, and tough as nails, with a high operational ceiling and a fast climb rate, it was in battle from Pearl Harbor to the Japanese surrender. While we had some great aircraft in WW2, NONE of them claimed more kills, and NONE of them fought the whole war. The really great performers didn't show up 'till the latter half, and the P-38 had been out there since Day 1.
He developed many others... the first operational US jet fighter P-80 Shooting Star... the F104 "Starfighter", the U-2 "Dragon Lady" high-altitude, high-endurance reconnaisance plane, the A-12 (SR-71) "Blackbird" was also a reconnaisance plane, but unlike the U-2, was very comfortable performing it's work from an even higher altitude, and at excess of Mach 3.
He also developed the AQM-60 Kingfisher- an unmanned vehicle... basically, a missle, it was identified casually as a 'target drone', but with it's ability to break Mach 4, wasn't within sight of anybody, or anything, long enough to actually become a 'target'... it was there, and gone, before anything would ever find it... but if it was equipped with appropriate guidance, it was certainly capable of running down, and punching a hole through any hypersonic missle. Wouldn't that be a handy gadget to have nowdays??
His boss noted "That damned swede can SEE AIR..."
He was known for his straightforward approach to engineering AND leadership, minimalisim of formality, and focus on simple, rapid solutions to problems.
Joe, you probably saw plenty of UFOs down there in your youth... I'd bet that most of them you saw (and all of them that you didn't) came to you right off'a Kelly's drawing board.
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Ten Amendments, Ten Commandments, and one Golden Rule solve most every problem. Citrus hand-cleaner with Pumice does the rest.
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DMiller
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Posted: 28 Feb 2020 at 7:48am |
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My Dad worked at McDonnell when was Just McDonnell Aircraft, saw the engineering that built the Voodoo(A LOSS), the F4, the F15 and 18, the AV8B. Kelly Johnson was a Valued star they all sought to duplicate but that man had vision no one else could reach.
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klinemar
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Posted: 28 Feb 2020 at 11:08am |
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I watched an interview a Lockheed Engineer that worked with Kelly Johnson. He told of the problems they had with the P38 and the Army thinking they knew how to correct the problems. The first was compressibility in a high speed dive.The Army added counter weights to the tail thinking extra weight would help the pilot control the aircraft. Kelly knew that was not the answer and wanted to put a P38 airframe in the Government run wind tunnel for testing. Turns out Kelly was right as the testing showed turbulence over the tail when the P38 approached the speed of sound in a dive freezing the controls and causing the aircraft to crash. Kelly designed a dive flap on the underside of the wing that could be deployed by the pilot entering a dive keeping him in control of the aircraft. The other problem was getting maximum performance from the Allison engines. The Army requested the wrong size turbocharger! After Kelly and the Lockheed test pilots did some tests they found the proper size turbos and along with 150 octane gas the P38 achieved phenomenal performance for a piston engined aircraft. Jets and the overall cost of a twin engined plane retired the P38.
Edited by klinemar - 28 Feb 2020 at 11:10am
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HD6GTOM
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Posted: 28 Feb 2020 at 11:20am |
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Right after WW2 and the Korean War, we had a branch of the Airforce establish an air Base at the Desk Moines Airport. They had some stationed there. I remember seeing them flying over the farm in the mid 1950's. Was always fascinated by the design.
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DaveKamp
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Posted: 01 Mar 2020 at 10:39am |
I don't know that the US Army ever had issues with the Allison's power output, but the P38 was developed prior to the US entering WW2, but it was ordered by the British, who specified that the turbosupercharger was NOT to be fitted. You may see it referred to as the P-38, and as the P-38 "Lightning"... I don't believe it was a formality, but I suspect the non-supercharged version was referred to colloquially as the "P-38" while "Lightning" was probably reserved for the full-power version.
As one would expect, the lack of turbosuperchargers had a dramatic impact on the Allison's performance, not just at high altitude, but also at low altitude. Why? Because the engine was built with comparatively LOWER compression ratio, to allow the turbosupercharger to operate at low altitude and high altitude, with no great 'hiccup' in power.
A TurboSupercharger is a combination device- it's a mechanically-driven compressor that at low speed, is spun by an overrunning clutch off the engine, and once there's sufficient exhaust pressure, it is increased in speed by an exhaust pressure turbine.
In locomotives, especially our big 2-stroke V's, the turbosuperchargers (usually two) are driven by a ball-type overrunning clutch, one on each end of the camshafts. In a 2-stroke, a supercharger is mandatory, otherwise, there would be no way for fresh air to enter the combustion chamber. In a locomotive, the supercharger has to effectively clear the cylinders after each stroke while CRANKING, which means it has to be basically a positive-displacement design. There's no exhaust pressure at starting, and very little while at idle, but once the throttle is moved up, exhaust flow through the turbine spins the blower faster, to create boost.
In the Allison aircraft, same concept applies, but it's a 4-stroke, so boost isn't necessary to run, but it's starting at (comparatively) low compression. Once it's at idle speed, the blower provides enough boost to make it snappy, and at working loads, exhaust pressure brings up boost substantially.
Britain didn't want turbosuperchargers because they didn't want to be limited to lower fuel grades. Because of their island circumstance, they were extremely limited in resources, particularly when German U-boats were amidst their 'happy hunting' timeframe of unrestricted warfare.
Anyway, the 'castrated' P38's performance was dismal at best.
A similar platform was the DeHavilland Mosquito, although larger and not quite as maneuverable, and being made of plywood, was very cheap (1/1th the cost of a P-38) fast was put into service into much of the same tactically-flexible purposes that the P-38 served, INCLUDING (like the P38) the installation of a very, very, very powerful cannon out the nose, for punching holes through surfaced submarines. The Mosquito's greatest weakness in comparison to the P38 was protective armor... they were structurally limited by spar and fuselage loading, so having substantial armor over sensitive areas and crew was not possible. It wasn't until later in the war that P-38's were brought into the European theatre by US Army Air Force. With our logistical capacity unthrottled by submarine threats, bringing in the twin-engine beast made the turbosupercharger fuel concern a non-issue.
The biggest advantage of the turbosupercharger, was the side-effect of design- the presence of the exhaust system plumbing and turbine made the P-38 extremely quiet.
The P-38 Lighting ruled the South Pacific. While the Vouight Corsair and a myriad of other aircraft were exemplary, the P-38 was an all-purpose denizen of the Japanese Empire.
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Ten Amendments, Ten Commandments, and one Golden Rule solve most every problem. Citrus hand-cleaner with Pumice does the rest.
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klinemar
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Posted: 01 Mar 2020 at 8:15pm |
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Dave I read where the Army Air Corps had a ban on the export of Turbochargers. And they did not want to sell Britain any as we needed every one. I will try and find the article. I read it many years ago.
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klinemar
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Posted: 01 Mar 2020 at 8:32pm |
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Dave the Army Air Corps stipulated Turbosupercharching in stead of mechanical supercharging because we did not have a two stage mechanical supercharger and Rolls Royce did on their Merlin engines . The P49 and first P51's were Allison powered with Mechanical single stage supercharger and they lacked high altitude performance. Both planes design made Turbo supercharging very difficult for placing the duct work. Both the P47 and F4U Corsair were Turbo supercharged. Without a two stage mechanical supercharger it was possible to over pressure the engine and detonate it if a pilot was not watching his manifold pressure. The P38 had this problem with the wrong turbo and a lack of automatic control of the doors for air to the turbos. This was corrected with the J and L models. With the advent of 150 octane fuel the P38,P47,P51 and F4U were able to achieve air speeds at altitude approaching 450mph.
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klinemar
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Posted: 01 Mar 2020 at 8:40pm |
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Also US fighters had War Emergency Power later in the war. A extra tank was mixed with Alcohol and Water and injected giving a boost of power in emergency conditions. The Germans used Nitrous oxide in their ME109 and FW190 fighters to give a power boost. One German pilot wrote after the war he came into a flight of P38's that saw him and put their throttles to the firewall. He turned on his Nitrous and seized his engine trying to catch them!
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