https://alternathistory.ru/glavnyj-samolet-villi-messershmitta-ot-projeck-p65-do-me-262/
"High-speed wing aerofoil and deflecting leading edge
By placing the main landing gear wheels within a relatively wide, triangular fuselage, the wing panels could be relatively thin and light, thereby enabling high flight speeds. Between 1939 and 1941, a series of tests were conducted at the AVA to determine the optimal wing aerodynamic profile. During these studies, Ludwig Bölkow earned his first laurels. He calculated and developed what would later become a popular high-speed airfoil, designated the 009-E4. After the end of World War II, this airfoil was used in the wing of the North American F-86 Sabre fighter. Ludwig Bölkow proposed making the Me 262 fighter's wing as thin as possible: he chose a 9% relative airfoil thickness at the wing roots instead of the originally planned 12%. At the wingtips, the relative wing thickness decreased to 6%. However, Willy Messerschmitt had serious doubts about the feasibility of accommodating leading edge slats within such a thin wing. Such a thin wing lacked even the space for the main landing gear. Ludwig Bölkow soon developed a technical solution in the form of a deflecting leading edge flap (the so-called Kippnase), which he patented and steadily developed. Ultimately, however, Bölkow's ideas were not implemented in the Me 262 design. Too many innovations could have provoked objections from the responsible and technically very conservative RLM staff, and so the aircraft's wing had a relative thickness of 12% and conventional leading edge slats.
Meanwhile, in September 1939, the Messerschmitt design bureau, headed by Walter Rethel, began work on the P 1065 project and began preparations for the creation and submission of drawings for the production facilities. On November 9, 1939, Messerschmitt submitted an improved design proposal, No. 1 (Projektangebot I), to the RLM, and on December 19, 1939, the first official inspection of the mockup of the future aircraft took place, which passed without any significant criticism.
On March 1, 1940, Messerschmitt received an official order for three prototypes and one static test airframe. On the same day, the equipment specifications for the first prototype, the P 1065 V-1, were determined. The aircraft was to feature airbrakes, self-sealing fuel tanks, a drag parachute, a pressurized, non-pressurized cabin, and, most notably, a Heinkel ejection seat.
Swept wing consoles
Meanwhile, two significant changes occurred during the development of the prototype's design. The BMW engines turned out to be larger and heavier than the engine engineers had anticipated, even with their less optimistic assumptions. This shouldn't be surprising, as turbojet engines were a new field of engineering and technology. However, these changes created serious problems for Messerschmitt, as they resulted in a shift in the P 1065's center of gravity. As development progressed, the wing sweep was increased as an emergency solution to the shift in the center of gravity. It's worth noting that at that point, no one in the Messerschmitt design bureau yet understood the advantages of swept wings for this speed range. Thus, a simple coincidence led to the Me 262 becoming the world's first jet fighter with swept wings! In May 1940, Messerschmitt submitted a modified design to the RLM as Improved Design Proposal No. 2 (Projektangebot II).
The second major change concerned the engine installation. For a long time, Messerschmitt design engineers favored placing the engines within the wing panels, a rather complex design. However, the aerodynamic advantages seemed to justify this additional effort, but as the weight and volume of BMW turbojet engines increased, the decision was made to abandon the internal mounting. All attention was focused on placing the engines in nacelles beneath or above the wing panels. Extensive wind tunnel research was conducted, and although the final configuration remained unclear for a long time, the design and production of tooling for the first two prototypes proceeded at the same pace. The final layout, with the engines placed in nacelles beneath the wing panels, ensured aerodynamic cleanliness on the upper wing surfaces and also ensured smooth airflow around the lower fuselage. The distance between the nacelles was large enough due to the fuselage being mounted above the wing centre section, thereby significantly reducing the harmful effects of interference.
From May 30, 1940 to April 4, 1941, the final transfer of the project (III) to the design bureau took place, and in February 1941, the P 1065 project received the official type designation 8-262 in the RLM.
Willy Messerschmitt reluctantly accepted the final version of the P 1065 design. He didn't immediately accept deviations from his optimal concept, particularly regarding the engine nacelle arrangement. Yet, Messerschmitt later called the Me 262 his most important aircraft, as no other of his designs would have led to so many important discoveries in the field of aviation technology!"