Off the floor unfinished Picture

Off the floor finished

Okay this one and a few others are for a Transformers contest that this person [link] is having. As for my entries, I am basing all of my design off of current vehicles than going on the ones that have been play way too many times. This one is based off this design [link] I have come across as I was looking for vehicles to base my characters on.

A little vehicle history note: Lockheed designed the P-38 in response to the 1937 United States Army Air Corps Circular Proposal X-608 request for a high-altitude interceptor aircraft having "the tactical mission of interception and attack of hostile aircraft at high altitude". Specifications called for a maximum airspeed of at least 360 miles per hour (580 km/h) at altitude, and a climb to 20,000 feet (6100m) within 6 minutes;[6] the toughest set of specifications USAAC had presented to that date. The Bell P-39 Airacobra and the Curtiss P-40 Warhawk were designed to the same requirement, as was the unbuilt Vultee XP1015.
The Lockheed design team, under the direction of Hall Hibbard and “Kelly” Johnson, considered a range of configurations.[7] All options considered by Lockheed were twin-engined, as it was judged that no single available engine was powerful enough to be able to meet the USAAC's requirements. (Engine development during World War II subsequently saw an approximate doubling of fighter engine horsepower, allowing many later single engine designs to achieve 400+ mph.)
The eventual design was relatively unique in comparison to existing fighter aircraft with only the Fokker G.1 and later Northrop P-61 Black Widow having a similar planform. The Lockheed team chose twin booms to accommodate the tail assembly, engines and turbo superchargers, with a central nacelle for the pilot and armament. The nose was designed to carry two Browning .50" (12.7 mm) machine guns with 200 rounds per gun, two .30" (7.62 mm) Brownings with 500 rounds per gun, and an Oldsmobile 37 mm cannon with 15 rounds. Clustering all the armament in the nose was unlike most other U.S. aircraft, which used wing-mounted guns where the trajectories were set up to crisscross at one or more points in a "convergence zone". The nose-mounted guns did not suffer from having their useful ranges limited by pattern convergence, meaning good pilots could shoot much farther. A Lightning could reliably hit targets at any range up to 1,000 yards (910 m), whereas other fighters had to pick a single convergence range between 100 and 250 yards (230 m). The clustered weapons had a "buzz saw" effect on the receiving end, making the aircraft effective for strafing as well.
The Lockheed design incorporated tricycle undercarriage and a bubble canopy, and featured two 1000 hp (746 kW) turbo-supercharged 12-cylinder Allison V-1710 engines fitted with counter-rotating propellers to eliminate the effect of engine torque, with the superchargers positioned behind the engines in the booms.[8] It was the first American fighter to make extensive use of stainless steel and smooth, flush-riveted butt-jointed aluminum skin panels. It was also the first fighter to fly faster than 400 mph (640 km/h).
Lockheed won the competition on 23 June 1937 with its Model 22, and was contracted to build a prototype XP-38[9] for US$163,000,[2] though Lockheed's own costs on the prototype would add up to US$761,000.[10] Construction began in July 1938 and the XP-38 first flew on 27 January 1939.[11] The 11 February 1939 flight to relocate the aircraft for testing at Wright Field was extended by General Henry "Hap" Arnold, commander of the USAAC, to demonstrate the performance of the aircraft. It set a cross-continent speed record by flying from California to New York in seven hours and two minutes,[8] but landed short of the Mitchel Field runway in Hempstead, New York, and was wrecked. However, on the basis of the record flight, the Air Corps ordered 13 YP-38s on 27 April 1939 for US$134,284 apiece.[12][1] (The initial "Y" in "YP" was the USAAC's designation for a "prototype" while the "X" in "XP" was for "experimental".)


Mechanized P-38 conveyor lines.
Manufacture of the YP-38s fell behind schedule, at least partly due to the need for mass-production suitability making them substantially different in construction than the prototype. Another factor was the sudden required facility expansion of Lockheed in Burbank, taking it from a specialized civilian firm dealing with small orders to becoming a large government defense contractor making Venturas, Harpoons, Lodestars, Hudsons, and designing the Constellation airliner for TWA. The first YP-38 was not completed until September 1940, with its maiden flight on 17 September.[13] The 13th and final YP-38 was delivered to the Air Corps in June 1941; 12 aircraft were retained for flight testing and one for destructive stress testing. The YPs were substantially redesigned and differed greatly in detail from the hand-built XP-38. They were lighter, included changes in engine fit, and the propeller rotation was reversed, with the blades rotating outwards (away) from the cockpit at the top of their arc rather than inwards as before. This improved the aircraft's stability as a gunnery platform.[11]


Cockpit view of a P-38G. Note the yoke, rather than the more-usual stick.
Test flights revealed problems initially believed to be tail flutter. During high-speed flight approaching Mach 0.68, especially during dives, the aircraft's tail would begin to shake violently and the nose would tuck under, steepening the dive. Once caught in this dive, the fighter would enter a high-speed compressibility stall and the controls would lock up, leaving the pilot no option but to bail out (if possible) or remain with the aircraft until it got down to denser air where he might have a chance to pull out. During a test flight in May 1941, USAAC Major Signa Gilkey managed to stay with a YP-38 in a compressibility lockup, riding it out until he recovered gradually using elevator trim.[8] Lockheed engineers were very concerned at this limitation, but first they had to concentrate on filling the current order of aircraft. Sixty-five Lightnings were finished by September 1941, with more on the way.
By November 1941, many of the initial assembly line challenges had been met and there was some breathing room for the engineering team to tackle the problem of frozen controls in a dive. Lockheed had a few ideas for tests that would help them find an answer. The first solution tried was the fitting of spring-loaded servo tabs on the elevator trailing edge; tabs that were designed to aid the pilot when control yoke forces rose over 30 pounds, as would be expected in a high-speed dive. At that point, the tabs would begin to multiply the effort of the pilot's actions. The expert test pilot, 43-year-old[14] Ralph Virden, was given a specific high-altitude test sequence to follow and was told to restrict his speed and fast maneuvering in denser air at low altitudes since the new mechanism could exert tremendous leverage under those conditions. A note was taped to the instrument panel of the prototype underscoring this instruction. On 4 November 1941, Virden climbed into YP-38 #1 and completed the test sequence successfully, but 15 minutes later was seen in a steep dive followed by a high-G pullout. The tail unit of the aircraft failed at about 3,000 ft (910 m) during the high-speed dive recovery; Virden was killed in the subsequent crash. The Lockheed design office was justifiably upset, but their design engineers could only conclude that servo tabs were not the solution for loss of control in a dive. Lockheed still had to find the problem; the Army Air Corps was sure it was flutter, ordering Lockheed to look more closely at the tail.
Although the P-38's empennage was completely skinned in aluminum (not fabric) and was quite rigid, in 1941, flutter was a familiar engineering problem related to a too-flexible tail. At no time did the P-38 suffer from true flutter.[15] To prove a point, one elevator and its vertical stabilizers were skinned with metal 63% thicker than standard—the increase in rigidity made no difference in vibration. Army Lt. Colonel Kenneth B. Wolfe (head of Army Production Engineering) asked Lockheed to try external mass balances above and below the elevator, though the P-38 already had large mass balances elegantly placed within each vertical stabilizer. Various configurations of external mass balances were equipped and dangerously steep test flights flown to document their performance. Explaining to Wolfe in Report No. 2414, Kelly Johnson wrote "...the violence of the vibration was unchanged and the diving tendency was naturally the same for all conditions."[16] The external mass balances did not help at all. Nonetheless, at Wolfe's insistence, the additional external balances were a feature of every P-38 built from then on.[17]


P-38 pilot training manual compressibility chart shows speed limit vs. altitude.
After months of pushing NACA to provide Mach 0.75 wind tunnel speeds (and finally succeeding), the compressibility problem was revealed to be the center of lift moving back toward the tail when in high-speed airflow. The compressibility problem was solved by changing the geometry of the wing's underside when diving so as to keep lift within bounds of the top of the wing. In February 1943, quick-acting dive flaps were tried and proven by Lockheed test pilots. The dive flaps were installed outboard of the engine nacelles and in action they extended downward 35° in 1½ seconds. The flaps did not act as a speed brake, they affected the center of pressure distribution so that the wing would not lose its lift.[18] Late in 1943, a few hundred dive flap field modification kits were assembled to give North African, European and Pacific P-38s a chance to withstand compressibility and expand their combat tactics. Unfortunately, these crucial flaps did not always reach their destination. In March 1944, 200 dive flap kits intended for ETO P-38Js were destroyed in a mistaken identification incident in which an RAF fighter shot down the Douglas C-54 Skymaster bringing the shipment to England. Back in Burbank, P-38Js coming off the assembly line in spring 1944 were towed out to the tarmac and modified in the open air. The flaps were finally incorporated into the production line in June 1944 on the last 210 P-38Js. The delay in bringing the dive flap and its freedom of tactical maneuver to the fighting pilot was far too lengthy. Of all Lightnings built, only the final 50% would have the dive flaps installed as an assembly line sequence.
Johnson later recalled:
“ I broke an ulcer over compressibility on the P-38 because we flew into a speed range where no one had ever been before, and we had difficulty convincing people that it wasn't the funny-looking airplane itself, but a fundamental physical problem. We found out what happened when the Lightning shed its tail and we worked during the whole war to get 15 more knots [28 km/h] of speed out of the P-38. We saw compressibility as a brick wall for a long time. Then we learned how to get through it.[19]

Buffeting was another early aerodynamic problem, difficult to sort out from compressibility as both were reported by test pilots as "tail shake". Buffeting came about from airflow disturbances ahead of the tail; the airplane would shake at high speed. Leading edge wing slots were tried as were combinations of filleting between the wing, cockpit and engine nacelles. Air tunnel test number 15 solved the buffeting completely and its fillet solution was fitted to every subsequent P-38 airframe. Fillet kits were sent out to every squadron flying Lightnings. The problem was traced to a 40% increase in air speed at the wing-fuselage junction where the chord/thickness ratio was highest. An airspeed of 500 mph (800 km/h) at 25,000 ft (7,600 m) could push airflow at the wing-fuselage junction close to the speed of sound. Filleting forever solved the buffeting problem for the P-38E and later models.[15]
Another issue with the P-38 arose from its unique design feature of outwardly rotating counter-rotating propellers. Losing one of two engines in any twin engine non-centerline thrust aircraft on takeoff creates sudden drag, yawing the nose toward the dead engine and rolling the wingtip down on the side of the dead engine. Normal training in flying twin-engine aircraft when losing an engine on takeoff would be to push the remaining engine to full throttle; if a pilot did that in the P-38, regardless of which engine had failed, the resulting engine torque and p-factor force produced a sudden uncontrollable yawing roll and the aircraft would flip over and slam into the ground. Eventually, procedures were taught to allow a pilot to deal with the situation by reducing power on the running engine, feathering the prop on the dead engine, and then increasing power gradually until the aircraft was in stable flight. Single-engine takeoffs were possible, though not with a maximum combat load.[20]
The engine sounds were a unique, rather quiet "whuffle", because the exhausts were muffled by the General Electric turbosuperchargers on the twin Allison V12s. There were early problems with cockpit temperature regulation; pilots were often too hot in the tropic sun as the canopy could not be opened without severe buffeting, and were often too cold in northern Europe and at high altitude, as the distance of the engines from the cockpit prevented easy heat transfer. Later variants received modifications to solve these problems.


P-38 at sunset.
On 20 September 1939, before the YP-38s had been built and flight tested, the USAAF ordered 66 initial production P-38 Lightnings, 30 of which were delivered to the USAAF in mid-1941, but not all these aircraft were armed. The unarmed aircraft were subsequently fitted with four .50s (instead of the two .50 and two .30 of their predecessors) and a 37 mm cannon. They also had armor glass, cockpit armor and fluorescent cockpit controls.[21] One was completed with a pressurized cabin on an experimental basis and designated XP-38A.[22] Due to reports the USAAF was receiving from Europe, the remaining 36 in the batch were upgraded with small improvements such as self-sealing fuel tanks and enhanced armor protection to make them combat-capable. The USAAF specified that these 36 aircraft were to be designated P-38D. As a result, there never were any P-38Bs or P-38Cs. The P-38D's main role was to work out bugs and give the USAAF experience with handling the type.[23]
In March 1940, the French and the British ordered a total of 667 P-38s, designated Model 322F for the French and Model 322B for the British. The aircraft would be a variant of the P-38E, without turbo-supercharging (due to a U.S. government export prohibition), and twin right-handed engines instead of counter-rotating, for commonality with the large numbers of Curtiss P-40 Tomahawks both nations had on order. After the fall of France in June 1940, the British took over the entire order and re-christened the plane Lightning I. Three were delivered in March 1942 and, after discovering, without superchargers, at low altitude and when using lower-octane British aircraft fuel, they had a maximum speed of 300 miles per hour (480 km/h) and poor handling characteristics, the entire order was canceled. The remaining 140 Lightning I's were completed for the USAAF with counter-rotating engines but still minus turbo-superchargers. Most were relegated to United States Army Air Forces training units under the designation RP-322.[24] These aircraft helped the USAAF train new pilots to fly a powerful and complex new fighter. A few Model 322 aircraft were later used as test modification platforms such as for smoke-laying canisters and dual air-dropped torpedoes. The RP-322 was a fairly fast aircraft (some of the fastest post-war racing P-38s were virtually identical in layout to the P-322-II)[25] at low altitude and well suited as a trainer. The other positive result of the failed British/French order was to give the aircraft its name. Lockheed had originally dubbed the aircraft Atalanta in the company tradition of naming planes after mythological and celestial figures, but the RAF name won out.
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