I have always loved the Airacobra in Royal Air Force markings, so when Kittyhawk announced their kit, thoughts turned to modifying it to represent a Mk 1 Airacobra as briefly used by 601 SQN
Research revealed there weren’t too many visible differences between the kit version and the one I wanted to model.  Fishtail exhausts, wheels, armament and a smaller diameter propeller being the main ones.  Mastercaster did wheels and exhausts for a Mk1.  Although made to fit the Special Hobby kit, they were easily adaptable to the KH kit.  Master of Poland supplied the gun barrels for wings and fuselage, the nose cannon being made from brass tubing.  I had planned to have the nose gun bay open, and had even gone as far as to replace the kit 37mm cannon with a 20mm hispano robbed from a HobbyBoss Spitfire, but in the end was not happy that I had portrayed the interior correctly, so reluctantly glued the panels shut.  The aerial mast was scratchbuilt from plastic strip, and the pitot tube came from a Trumpeter P-47
Overall I found the kit a reasonable build, although there were a couple of areas where fit was less than stellar, the wingroots being the main culprit.  This was due to the recess for the inner walls of the wheelbays not being deep enough.  The problem was solved by fitting the wings to the fuselage minus the wheelwell inner walls.  These were fitted after the wings were glued on.  To enable this, you need to cut the tabs off the wheelwell front and rear walls that the inner walls locate onto.  Do this and you will be rewarded with a join that just needs a smear of filler to hide.  It remains one of my favourite builds.

Bell P-39 Airacobra Mk1 601 SQN. Royal Air Force. Duxford 1941