On August 7, 1951 after excruciating delays due to engine development the first XF3-1 took flight in the hands of Robert M Edholm. Powered by a non-reheated J40-WE-6 the test aircraft was dangerously underpowered, and during the landing approach actually suffered a catastrophic engine failure.
Armed with the failure, and a history of delay after delay, the McDonnell team approached the Navy and advised them that the only way that the F3H was going to be able to continue was with an engine change. The Navy was faced with a harsh choice, but McDonnell had a series of design changes to propose.
The more basic ones were a 'simple' engine change. The P&W J57 and the Allison J71 were currently in development and McDonnell had the foresight to approach both manufacturers and get the expected specifications of both engines. Of the two the J57 was expected to be heavier, but also had higher thrust and was the better funded and more mature program per McDonnell's own engineers. The J57 was already flying in a test installation, while the J71 was languishing on the test stand for want of funding and prospective aircraft designs. McDonnell had also gotten verbal promises from P&W that a reheated version of the engine could be made available in Late 1952/Early 1953 with a non-reheated version available for test flight in Early 1952. These designs would require 'modest' reworking of the fuselage and wings, of which some work had already been done by McDonnell engineers on paper based upon their experience with the F3H as well as the XP-88 and it's follow on designs for the Air Force.
Also in the mix was a dual engine redesign of the fuselage with several prospective engine choices, the most powerful of which was a reheated version Wright J65 already selected by the Navy for the powerplant of what would become the FJ-3 Fury, and a version powered by the in production Allison J35. Unfortunately this redesign was going to be expensive as additional modeling and wind tunnel testing would be required for the development of the dual engine fuselage, and it was going to carry a significant weight penalty which would require an entire wing redesign to meet carrier landing requirements.
The Navy after deliberation signed a Letter of Intent to amend the F3H production powerplant to the J57, mainly due to budget issues. It was, of all of the choices put forth, the cheapest choice by far, and at this point the Navy was funding multiple airframe developments and had little to no budget left for expensive redesigns. What was more telling, to the Navy, was that it's backup of three other deeply troubled projects (the F4D, the F10F, and the F7U) it was, despite the issues with the engine either most mature machine, or the one with the least number of troubling flight characteristics. The move to the J57 was what the Navy saw as the 'safe' choice at the time.
McDonnell immediately began reworking the two XF3-1 prototypes for the newly chosen J57 engine, receiving from P&W an empty, ballasted engine shell complete with accessories and a mock afterburner. At the same time they began prototyping a new, larger, wing for the heavier aircraft using test data from their use of the NACA 65A00x series on the XF-88 Voodoo prototype. The wing was broadened in chord at the root by forty inches to increase wing area although span was kept the same resulting in a . The prototype wings were built on a NACA 65A007 plan at the root, thinning to NACA 65A006 at the tip with a 45 degree designed sweep at the quarter line. This design was expected to have less parasitic drag than the NACA 0006 series originally chosen for the wing, and as a redesign to a larger wing area was needed anyways, and no retooling costs were involved, it was seen as a perfect time to test it.
By April 1952 prototype 1 with the original 442 sqft NACA 0006 series wing and protype 2 with the newly designed 519 sqft NACA 65A00x wing were awaiting delivery of the evaluation J57 engine. By May 1952 McDonnell had delivery of two pre-production evaluation J57 engines rated at 9000 lbs of thrust dry. Initial test flights of both prototype aircraft by Robert E Edholm (flown back to back on the same day) were incredibly promising. In a stark contrast to his somber mood after the first test flight of the XF3-1 he was all but ecstatic in his praise of the new aircraft as it had ~30% more thrust with nearly the same dry weight. The test series did show deficiencies with the installation, prospective series production, and range of the new engine. Additionally, the new wing showed issues during high angles of attack where the airflow became detached from the wing, leading to loss of roll control and almost the loss of the aircraft. Fences were installed just inboard of the ailerons in an attempt to correct this issue, but the final correction was found in wind tunnel testing to be a 'dogtooth' transition of the leading edge of the wing. Carrier suitability testing was carried out with Prototype 2 during September of 1952 after the new dogtoothed outer wing panels were built and extensively tested.=. Two new protoypes are ordered by the Navy for delivery in Q1 1953 with the required production changes to the fuselage. These were most notable a change to the engine intakes as they moved six inches aft so that they could be enlarged to provide better airflow, a movement of the wing from 'hip' to 'belly' mounting to simplify the changed needed to mount the larger engine and carry the required strength of the fuselage to wing mounting structure, a move of the fuselage from oval in total form to being straight sided from the midline down to accommodate the required fuel increase, the cockpit and nose were canted down at five degrees to give better visibility, and a shorter, enlarged nose was designed to house the newly specified APD-50 radar.
October 1952 McDonnell received the first Afterburning variants of the J57. Rated at 10000 lbs dry and 13500 lbs wet and featured a crude but workable 'eyelid' nozzle to control engine turbine pressure for dry and reheat operation. Testing of the two prototypes showed that the changed wing design was as fast on the same power settings and experienced significantly less transonic buffeting as velocities reached, and in the case of of prototype 2 exceeded the speed of sound in a shallow dive. December 3 1952 the XF3-1 prototype 2 airframe became the first Navy prototype, and first US prototype of a production jet to exceed the speed of sound.
The US Navy immediately ordered two additional pre-production prototypes with the fuselage design changes and the redesigned wing for delivery in 1953, with plans to move the plane in full production by fourth quarter 1953 as the Navy needed a new production jet immediately given delays and failures in other products as well as the outstanding success that McDonnell had seen in the new jet. Additionally, the US Navy contracted P&W for delivery of the necessary P&W J57 afterburning engines (expected 15K lb+ wet thrust and with a new nozzle) starting no later than Q2 1953.
Additional issues were found with the XF3-2 prototypes when they first flew in May of 1953 mostly with compressor stalls with the engine during rapid throttle increases at high angles of attack and/or speed, and the necessity of wing spoilers to provide aileron input at high speeds, but the US Navy considered those issues minor given the performance of the super sonic jet, and ordered delivery of the 150 planes contracted in March 1951 (prior to the first flight of the prototype!) along with an additional 100 planes.
December of 1953 the first operational squadrons of the F3H-1 Demon were deployed, beginning it's long and storied history which stretched 2 decades in US service and 5 decades in foreign service. Eventually a Dual Cockpit version (F3H-2 pilot/RIO) became the US Navy standard when it transitioned to Missile Armament, providing a template that was used for the F4 Super Demon when it became operational in 1959 powered by two J57-P-8 engines. The single cockpit design of the F3H was eventually embraced by the US Airforce, who faced immense issues with the own development of a super sonic fighter, the F100 being outright canceled due to a rash of fatal accidents, and the F101 Voodoo, a McDonnell product itself, being deemed as 'insufficiently capable' by the McDonnell when compared to the F3H in front of congress. Eventually the F4 Super Demon was also accepted by the Airforce albeit in a single cockpit variant, where it was well loved by the service and the pilots who flew it.
Armed with the failure, and a history of delay after delay, the McDonnell team approached the Navy and advised them that the only way that the F3H was going to be able to continue was with an engine change. The Navy was faced with a harsh choice, but McDonnell had a series of design changes to propose.
The more basic ones were a 'simple' engine change. The P&W J57 and the Allison J71 were currently in development and McDonnell had the foresight to approach both manufacturers and get the expected specifications of both engines. Of the two the J57 was expected to be heavier, but also had higher thrust and was the better funded and more mature program per McDonnell's own engineers. The J57 was already flying in a test installation, while the J71 was languishing on the test stand for want of funding and prospective aircraft designs. McDonnell had also gotten verbal promises from P&W that a reheated version of the engine could be made available in Late 1952/Early 1953 with a non-reheated version available for test flight in Early 1952. These designs would require 'modest' reworking of the fuselage and wings, of which some work had already been done by McDonnell engineers on paper based upon their experience with the F3H as well as the XP-88 and it's follow on designs for the Air Force.
Also in the mix was a dual engine redesign of the fuselage with several prospective engine choices, the most powerful of which was a reheated version Wright J65 already selected by the Navy for the powerplant of what would become the FJ-3 Fury, and a version powered by the in production Allison J35. Unfortunately this redesign was going to be expensive as additional modeling and wind tunnel testing would be required for the development of the dual engine fuselage, and it was going to carry a significant weight penalty which would require an entire wing redesign to meet carrier landing requirements.
The Navy after deliberation signed a Letter of Intent to amend the F3H production powerplant to the J57, mainly due to budget issues. It was, of all of the choices put forth, the cheapest choice by far, and at this point the Navy was funding multiple airframe developments and had little to no budget left for expensive redesigns. What was more telling, to the Navy, was that it's backup of three other deeply troubled projects (the F4D, the F10F, and the F7U) it was, despite the issues with the engine either most mature machine, or the one with the least number of troubling flight characteristics. The move to the J57 was what the Navy saw as the 'safe' choice at the time.
McDonnell immediately began reworking the two XF3-1 prototypes for the newly chosen J57 engine, receiving from P&W an empty, ballasted engine shell complete with accessories and a mock afterburner. At the same time they began prototyping a new, larger, wing for the heavier aircraft using test data from their use of the NACA 65A00x series on the XF-88 Voodoo prototype. The wing was broadened in chord at the root by forty inches to increase wing area although span was kept the same resulting in a . The prototype wings were built on a NACA 65A007 plan at the root, thinning to NACA 65A006 at the tip with a 45 degree designed sweep at the quarter line. This design was expected to have less parasitic drag than the NACA 0006 series originally chosen for the wing, and as a redesign to a larger wing area was needed anyways, and no retooling costs were involved, it was seen as a perfect time to test it.
By April 1952 prototype 1 with the original 442 sqft NACA 0006 series wing and protype 2 with the newly designed 519 sqft NACA 65A00x wing were awaiting delivery of the evaluation J57 engine. By May 1952 McDonnell had delivery of two pre-production evaluation J57 engines rated at 9000 lbs of thrust dry. Initial test flights of both prototype aircraft by Robert E Edholm (flown back to back on the same day) were incredibly promising. In a stark contrast to his somber mood after the first test flight of the XF3-1 he was all but ecstatic in his praise of the new aircraft as it had ~30% more thrust with nearly the same dry weight. The test series did show deficiencies with the installation, prospective series production, and range of the new engine. Additionally, the new wing showed issues during high angles of attack where the airflow became detached from the wing, leading to loss of roll control and almost the loss of the aircraft. Fences were installed just inboard of the ailerons in an attempt to correct this issue, but the final correction was found in wind tunnel testing to be a 'dogtooth' transition of the leading edge of the wing. Carrier suitability testing was carried out with Prototype 2 during September of 1952 after the new dogtoothed outer wing panels were built and extensively tested.=. Two new protoypes are ordered by the Navy for delivery in Q1 1953 with the required production changes to the fuselage. These were most notable a change to the engine intakes as they moved six inches aft so that they could be enlarged to provide better airflow, a movement of the wing from 'hip' to 'belly' mounting to simplify the changed needed to mount the larger engine and carry the required strength of the fuselage to wing mounting structure, a move of the fuselage from oval in total form to being straight sided from the midline down to accommodate the required fuel increase, the cockpit and nose were canted down at five degrees to give better visibility, and a shorter, enlarged nose was designed to house the newly specified APD-50 radar.
October 1952 McDonnell received the first Afterburning variants of the J57. Rated at 10000 lbs dry and 13500 lbs wet and featured a crude but workable 'eyelid' nozzle to control engine turbine pressure for dry and reheat operation. Testing of the two prototypes showed that the changed wing design was as fast on the same power settings and experienced significantly less transonic buffeting as velocities reached, and in the case of of prototype 2 exceeded the speed of sound in a shallow dive. December 3 1952 the XF3-1 prototype 2 airframe became the first Navy prototype, and first US prototype of a production jet to exceed the speed of sound.
The US Navy immediately ordered two additional pre-production prototypes with the fuselage design changes and the redesigned wing for delivery in 1953, with plans to move the plane in full production by fourth quarter 1953 as the Navy needed a new production jet immediately given delays and failures in other products as well as the outstanding success that McDonnell had seen in the new jet. Additionally, the US Navy contracted P&W for delivery of the necessary P&W J57 afterburning engines (expected 15K lb+ wet thrust and with a new nozzle) starting no later than Q2 1953.
Additional issues were found with the XF3-2 prototypes when they first flew in May of 1953 mostly with compressor stalls with the engine during rapid throttle increases at high angles of attack and/or speed, and the necessity of wing spoilers to provide aileron input at high speeds, but the US Navy considered those issues minor given the performance of the super sonic jet, and ordered delivery of the 150 planes contracted in March 1951 (prior to the first flight of the prototype!) along with an additional 100 planes.
December of 1953 the first operational squadrons of the F3H-1 Demon were deployed, beginning it's long and storied history which stretched 2 decades in US service and 5 decades in foreign service. Eventually a Dual Cockpit version (F3H-2 pilot/RIO) became the US Navy standard when it transitioned to Missile Armament, providing a template that was used for the F4 Super Demon when it became operational in 1959 powered by two J57-P-8 engines. The single cockpit design of the F3H was eventually embraced by the US Airforce, who faced immense issues with the own development of a super sonic fighter, the F100 being outright canceled due to a rash of fatal accidents, and the F101 Voodoo, a McDonnell product itself, being deemed as 'insufficiently capable' by the McDonnell when compared to the F3H in front of congress. Eventually the F4 Super Demon was also accepted by the Airforce albeit in a single cockpit variant, where it was well loved by the service and the pilots who flew it.
