【Project Seahorse】
North American ETF-51D Seahorse,1945.

"Project Seahorse"
P-51D-5-NA serial number 44-14017 by North American Aviation in Dallas, Texas.
To enhance low speed handling, it was fitted with a fin fillet extension.
This was a standard retrofit for early-series P-51D aircraft. The other modifications were specific to the new naval role of the aircraft. A tailhook was fitted, attached to a reinforced bulkhead. A catapult hook was fitted on the fuselage centerline, just forward of the wing. To cope with hard carrier landings, the tires were replaced with special high-pressure ones. The main undercarriage shock absorbers received increased air pressure to reduce bouncing upon landing. The airframe was also reinforced in various points to withstand the extra stress.
Thus modified, 44-14017 was redesignated ETF-51D and sent to Mustin Field, near Philadelphia, for initial testing in September 1944.
The pilot in charge of testing the ETF-51D was Navy Lieutenant Robert M. Elder. He was an experienced naval test pilot who had already conducted carrier-suitability trials with several types of aircraft.
One of the runways at Mustin Field was specially modified in order to test the naval Mustang. Markings simulating the size of an aircraft carrier's deck were realized and arrester cables were installed, as well as a launch catapult.
During the months of September and October 1944, Lt. Elder made nearly 150 simulated launches and landings
with the ETF-51D. Sufficient data concerning the Mustang's low speed handling had to be gathered before carrier trials could begin. The Mustang's laminar-flow wing made for little drag and high speed but was relatively inefficient at low speed, resulting in a high stall speed. As the arrester cables could not be engaged at more than 90 mph, Elder reported that ?from the start, it was obvious to everyone that the margin between the stall speed of the aircraft (82 mph) and the speed imposed by the arrester gear (90 mph) was very limited.