Originally posted by Tac:
Unlike the Go-229, the P-38K did fly as a working prototype, albeit it being a heavily modified P-38E.
Actually, the first P-38J-1-LO was taken from the production line and fitted with the F-15 engines and the HS props. This plane was delivered to the AAC for testing. The modified E model also served as the test mule for the J model intercoolers. So, there was the modified P-38E that was used to test the concept as an unofficial XP-38K, and the P-38K-1-LO, which was a reworked P-38J-1-LO.
Therefore, two examples were actually built.
All test data comes from Warren Bodie's personal archive, although the original P-38K test report generated at Eglin Field can be obtained from the National Archives on microfilm (you must buy the entire roll) or visit the their facility in College Park, Maryland (just northeast of Washington, D.C.), where you can scroll through the roll and print a photocopy. It's a good idea to to plan on spending several days searching for specific documents. Most of the microfilm rolls are not indexed for content.
My regards,
Widewing