vertical tail surfaces. Operational history On 6 February 1940, the Swedish government ordered 144 Vanguards as the V-48C. The production prototype flew on 6 September 1940. The model V-48C was similar to the V-48X except for installation of a later version of the R-1830 engine with better higher altitude performance and provision for four machine guns in the wings and two machine guns in the fuselage. When production deliveries began in September 1941, the U.S. government placed an embargo on exporting the aircraft to Sweden. In the aftermath of Pearl Harbor, all Vanguards were assigned the designation P-66. Production ended in April 1942. Approximately 50 aircraft were retained by the USAAF and primarily used at pursuit training bases in the western U.S. and were deployed to the 14th Pursuit Group in defensive roles. Although pilots were impressed by the P-66's handling, the type was considered less than robust and a tendency to ground-loop led to 15 aircraft being destroyed in landing accidents. The British government took possession of 100 P-66s as the Vanguard I with plans to use the aircraft as an advanced trainer in Canada. After concluding their trials however, the British then relinquished the aircraft to China where 104 Vanguards (including USAAC examples) were shipped under the Lend-Lease program. They were originally intended to equip the 3rd American Volunteer Group (AVG); however, plans for additional groups were dropped after the Japanese attack on Pearl Harbor. The Chinese received the assembled fighters via India by late 1942; Chinese Vanguards had USAAF insignia and serials as well as Chinese markings and Vultee serials on factory models. The undistinguished combat record of the Vanguard in China was due to problems that began in transit where a number of Vanguards were destroyed during tests in India and others lost while en route to China. Assembled P-66s were deemed unairworthy and abandoned at Karachi resulting in only 12 Vanguards on station at Kunming with the 74th Fighter Squadron of the 23rd Fighter Group, but this unit saw little action. Two Chinese squadrons from the 3rd Group and the 5th Group based at An-Su saw combat action with the Vanguard from August 1943 onward. However, many P-66s were destroyed on the ground during Japanese attacks while several were shot down in error when they were mistaken for the Nakajima firm's Ki-43 "Oscar" and Ki-44 "Tojo". Although the Vanguard possessed a top speed of ,