The 75th Fighter Squadron, in which Rode and I had served in China, held its first postwar reunion in September 1948 in Cleveland in conjunction with the National Air Races. We flew to Akron, where Wes Posvar, who was on leave in Cleveland, met us and drove us to the hotel. Wes didn't attend the reunion but joined us at the air races. There was quite a good turnout at the reunion, considering that so many of the squadron were still on active duty and were not able to make it. Our hotel bill was a bit higher than anticipated because one of our less-intelligent members, nicknamed the Talking Dog in China, poured a pitcher of drinks into a piano and threw a small table out a fifteenth-floor window. (It landed in an alley and didn't kill anyone. If it had, it would have been his first victory.)
The air races were of special interest to me because my friend from test pilot school, Chuck Brown, who had left the Air Force and become a test pilot for the Allison Engine Company, had entered a P-39 in the Thompson Trophy Race. I visited him in the hangar on the day before the race and inspected his Airacobra. It had been cleaned up aerodynamically to reduce the drag, and the wings had been shortened. What really amazed me was the engine. The normal takeoff power setting on a standard Allison, as used in the F-82, was 72 inches of mercury and 3,200 rpm. Chuck said that by using special fuel, he would pull 120 inches and 3,400 rpm at the start of the race and then reduce power in increments on each of the twenty laps. He said he planned to take off in first place and stay there throughout the race because the first-place plane is out of the rough air created by the prop-wash of the other planes, and its risk of collision is much less. Chuck was a superb pilot, and I was sure he would win if his engine held up, but it did not. Chuck, as promised, was the first off the ground and easily led the pack. Making picture-perfect turns around the pylons, he lapped many of the others. In the eighteenth lap, though, an overheated fuel line caused vapor lock, and his engine failed. He brought the Airacobra in for a dead-stick landing.
Not long afterward Chuck left Allison and became a test pilot for North American Aviation. The next year he was flying as the copilot in an AJ, a Navy bomber powered by two wing-mounted reciprocating engines and a jet engine in the aft fuselage. During some yaw tests, the tail came off and the AJ crashed into the ocean, killing both pilots.
We now had several F-84s, both B and C models, in the squadron, and I was flying them regularly. The C was essentially the same as the B except for 250 pounds of additional thrust from the engine and an improved electrical system. The F-84 was faster than the F-80 at all altitudes but had a lower rate of climb. Its range as a fighter-bomber was double that of the F-80 because the 84 could carry both drop tanks and bombs. The 80, which used the same racks for the drop tanks and the bombs, could not carry both at once. It was an easy airplane to fly, and the wide landing gear and the solid feel common to Republic fighters made it especially easy to land.
Three test programs on the F-84B were under way at Eglin during the period from March through December 1948: operational suitability, armament installation, and a brief test of the retractable bomb rack. The tests all were started just before I returned from test pilot school. Hoot Gibson was the test officer on the suitability test, Don Dessert on the armament test, and Si Johnson on the bomb-rack test. Many problems, some serious, were discovered in the course of this testing, requiring major modifications to the aircraft. I did not participate in the bomb-rack test, which consisted primarily of ground missions, or in the armament test, but I flew quite a few missions in the suitability test program. Don Dessert, as test officer, was the principal pilot, but he was ably supported by pilots from the 20th Fighter Group, which was to be equipped with the F-84. It was common practice at Eglin for pilots from operational groups to fly with Eglin pilots during tests of aircraft they were to operate.
The armament testing was to evaluate the gun installation, which consisted of six .50-caliber M3 machine guns, four in the upper nose section and one in each wing root, with 300 rounds of ammunition per gun. The gunsight was a K-14B with a hydraulic ranging mechanism. During the course of the program 62,533 rounds of ammunition were fired. In the functional phase the guns were fired in fifty-round bursts in straight-and-level flight, in pullouts and turns at 1 to 6 g's, and in minus-1-g pushovers at altitudes from 10,000 to 40,000 feet. Every malfunction, including cookoffs, was recorded along with the altitude, airspeed, and number of g's at which the malfunction occurred. A cookoff is caused by a gun becoming so hot that the round in the chamber fires without being struck by the firing pin. In combat a cookoff is startling to the pilot because it sounds as though his airplane has been hit. Although this was run as a separate series of tests, the results became part of the suitability test report.
Instead of summarizing the results of the tests, I have excerpted the following paragraphs from the final report of Air Proving Ground Project No. 6478-45, Operational Suitability Test of the F-84B Airplane.
3. CONCLUSIONS:
a. The F-84B does not perform satisfactorily any of the following missions:
(1) Fighter-Bomber.
(2) Escort-Fighter.
(3) Ground-support Fighter.
(4) Interceptor-Fighter.
b. Jet aircraft, as typified by the F-80 and F-84, have less utility of employment than conventional aircraft; i.e., excessive fuel consumption, especially at low altitudes, severely limits the tactical utilization of jet aircraft.
4. RECOMMENDATIONS:
It is recommended that:
a. A study be made to determine the feasibility of modifying the F-84Bs now produced to enable the airplane to perform satisfactorily a combat or training mission.
b. The structural integrity flight demonstration requirements for jet airplanes (AAF Specifications Nos. C-1803-E and F-1803-11) be revised to increase or decrease the maximum permissible ''g" loading at low altitudes commensurate with the mission for which the aircraft is designed.
5. DISCUSSION:
a. Generaclass="underline" Due to grounding orders and excessive time required to perform the many modifications made necessary by structural difficulties, the number of hours flown on the five aircraft available for service was small. A breakdown of total hours flown during all testing is as follows:
(1) Aircraft suitability 14 hrs. 35 min.
(2) Bombing 25 hrs. 30 min.
(3) Armament 35 hrs. 25 min.
(4) Electronics 17 hrs. 50 min.
(5) Transition 12 hrs. 10 min.
TOTAL 105 hrs. 30 min.
b. Structural Failures: The wing construction of the F-84B has been the main source of difficulty with the airplane. Pulled rivets, wing wrinkling and buckling were encountered when the airplane was submitted to loads greater than 6 "g" at speeds in excess of 400 mph IAS [indicated airspeed]. All aircraft exhibited these inherent weaknesses. Structural failures necessitated replacing the wings of three aircraft, and less severe indications of failure were apparent on the other two. The airplane was limited to a 6 "g" acceleration and speeds less than 450 mph IAS, which precluded any low-level, high-speed tactical operation because of the high wing-loadings encountered in the performance of such missions. It was found that pilots often inadvertently exceeded this limit during pullout regardless of their awareness of the restriction. Even in unaccelerated level flight at high speeds, loads as high as 6 "g" due to turbulent air at low-level have been recorded. Failure of the wing trailing edge brackets and wing fairing forward of the aileron cut-out area was apparent after early inspection of all aircraft. These failures are believed to have been a contributing cause of a fatal accident which occurred during the test, the aircraft disintegrating in flight at low-level. Resulting corrective action was to reinforce the brackets to prevent further occurrences. Only limited bombing and armament testing could be conducted because of the structural limitations and failures.