10/31/2013. Remarks by Johan Visschedijk: "The Model E75 was the only attempt at standardizing Army and Navy Stearmans. Full interchangeability between the Army model PT-13D Kaydet and the Navy model N2S-5 Kaydet was achieved in 1942, both were fitted with the Lycoming R-680-17 radial engine.

The 1,768 that were delivered between June 1943 and February 1945, were built under the USAAF serials 42-16846 to 42-17863 (c/n 5009 to 6026) and 42-109026 to 42-109775 (c/n 8059 to 8808), while in addition the USN allotted 1768 BuNos, 60887 to 61904, 38438 to 38610, 43138 to 43637 and 52550 to 52626.

All factory fresh aircraft had the Army designation PT-13D and serial painted on the fuselage just ahead of the forward cockpit, the 872 N2S-5s transferred to the Navy had the designation N2S-5 and the BuNos. painted on the vertical tail as well. The BuNos. allotted to the 896 PT-13Ds delivered to the Army were simply not taken up."