Lest we forget ...
COIN Mustangs were the result of the idealistic United Nations stance that wars could be controlled by limiting weapon capability and technology to third world countries ... excluding nuclear weapons, jets, large vessels, etc. Of course, though signatories, Russian bloc, Chinese, French, and Indo Asian countries weaseled around bans. A major reason South Vietnam was equipped early on only with ADs, AT-28s, P-51s, C-47s, C-123s, B-26s, H-34s, H-21s, etc.
Cavalier turbo Mustang III: North American P‑51D Mustang, originally built by Trans Florida Aviation for executive use. Trans-Florida was renamed Cavalier Aircraft Corporation and purchased the rights of the P-51 design from North American. Over time, it was also adapted for military export roles. In 1967, the USAF contracted with Cavalier to produce the Merlin F-51D for export to South America under the Military Assistance Program (MAP), named "Mustang II"; a total of 9 were built for El Salvador. In 1968, two Mustang IIs went to the U.S. Army as chase planes for the Cheyene (AH-54) helicopter. Orders were placed in 1972 for 6 aircraft under MAP for export to Indonesia.
The Mustang IIs did not have wingtip fuel tanks.
The "Turbo Mustang III" variant is a later, highly modified version that replaces the Merlin engine with another Rolls‑Royce product, an Aussie built Dart turbo‑prop, giving it a unique propulsion system and altered airframe features. With a strengthened wing, Mustang IIs were re-designed for a combat load capacity of up to 5,000 lbs. across six hardpoints, alongside six 12.7 mm Browning M2 or M3 machine guns.
Turbo Mustang III had the CG sensitive rear 85 gal. fuselage tank removed, relying on new tip tanks. It may have installed a second seat.
When Cavalier closed in 1971, they sold the rights to Piper, which had better production facilities.
Only one prototype of the Cavalier Turbo Mustang III was built, and it went to Piper, although 25+ of their various Merlin versions have been suggested.
Piper PA-48 Enforcer: is a turboprop-powered close air support and counter-insurgency aircraft. It evolved from surplus P-51 Mustangs modified by Cavalier Aircraft (such as the Turbo Mustang III) before
Piper Aircraft acquired the rights and turbo prototype in 1971 and redesigned it completely into a dedicated ground-attack machine. Powered by a Lycoming YT55-L-9 turboprop engine, a heavily modified and lengthened fuselage, new strengthened wings, and ceramic armor protection compared to the classic P-51.
Built with 10 wing hardpoints capable of carrying up to 6,200 lbs of ordnance, including bombs, 2.75" rocket pods and 30 mm GAU-13/A rotary cannons. Evaluated by the U.S. Air Force in the late 1970s and 1984 under the Pave COIN program. 4 built, one in Pima Museum.
By the time the PA-48s were completed, they shared less than 10 percent of their structure with the Piper P-51s were longer and larger, almost a completely new aircraft, that shared less than 10% of its airframe with the original P-51.
Neither the U.S. military nor any foreign operators purchased either Turbo Mustang.
Both featured an extended nose to balance the lighter turboprop, most had wing tip tanks, and there were several configurations of larger vertical tail surfaces.
Note the turbine exhaust is on opposite sides to distinguish the manufacturer visually. That, different engines, weapons and hard points, plus Piper had a completely new and stronger wing structures with different airfoils to make them very different when examined more closely.
