On January 9, 1943, after the last inspections had been carried out by the USAAF and Lockheed, the XC-69 finally took to the skies.
For the occasion, Lockheed had borrowed the Boeing Aircraft Company’s chief test pilot, Edmund Allen.
Allen was one of a small number of pilots to have experience with the R-3350 and was the test pilot for the Boeing B-29 Superfortress bomber, the role for which the R-3350 was originally developed.
Lockheed test pilot Milo Burcham, who was known for flying the prototype Lockheed P-38 Lightning, acted as co-pilot during the flight.
Both Allen and Burcham traded control of the aircraft during the entire experience.
Both designers, Clarence “Kelly” Johnson and R.L. Thoren were also present on the flight (the latter acting as the flight engineer).
The aircraft landed at Muroc Dry Lake (presently Edwards Air Force Base) and conducted four successful take-offs and landings.
Burcham flew the XC-69 back to Burbank in 31 minutes.
In total, the XC-69 performed six separate flights all adding up to 129 minutes.
Two aircraft, a Boeing B-17 Flying Fortress and a Lockheed L-18 Lodestar acted as photo chase aircraft.
After the experience Allen commented, “This machine works so well that you don’t need me anymore!” Allen returned to Boeing.
A seventh flight took place on January 18.
This time, the landing gear doors were placed on the aircraft so the gear could be retracted (this was not done earlier to avoid any landing gear failure).
On July 28, 1943, the XC-69 was symbolically handed over to the USAAF at Las Vegas, Nevada and given a military serial number 43-10309.
Later that same day, the XC-69 returned to Lockheed for further testing.
It is worth mentioning that the C-69 was able to attain a higher maximum speed than the Japanese Mitsubishi A6M Zero fighter.
Unfortunately for Lockheed, the C-69 became less important to the war effort as time progressed, especially since the tide of the war had turned in favour of the Allies.
Only a small number of C-69 aircraft would see service in the last year of the war.
Even so, Lockheed was able to conduct tests at the expense of the government to solve problems with the aircraft’s design.
Although the problems with the R-3350 were being solved, the B-29 had priority for the engines over the C-69.
Even with all the effort put forth by Lockheed, the USAAF favored the C-54 Skymaster over the C-69.
At the end of the war, only 22 C-69s were produced (seven of which were never delivered).
Except for the C-69C, all other C-69s were declared surplus and sold on the civilian market between 1946 and 1947.
These would later be converted by Lockheed into L-049 passenger aircraft for airline usage.
The prototype XC-69 was converted into the sole XC-69E, which tested the possibility of using the R-2800 in place of the R-3350.
This never happened.
