That's strange as I was posted initially to RAF Marham where No 115 Squadron were equipped with the Washington, recognised by all in Bomber Command as the B 29. XV Squadron Washingtons had already been phased out with the Canberra at Marham. I had passed out as an Air Radar Mechanic from RAF Yatesbury, traIned on the H2S4A gear, the latest gear fitted to the Lincoln B2. The B 29 had AN/APQ13 bombing radar fitted and I was told that I would have had to undertake "on station" course to convert.....the AN/APQ 13 was the USAAF H2X type developed from H2S and fitted on B 29s .......technology which had been passed on to the USAAF during war.In the end that posting was cancelled as a friend of mine on the same course said he would like to have an exchange posting as his home was at Downham Market and his posting was Hemswell,so I went to Hemswell instead which suited me as my home was in the West Riding of Yorkshire. The RAF Washingtons were B 29As taken from a cocooned status or about to be cocooned stored...surplus to USAF requirements and designated by the RAF as Washington B1s. The B 50 was an enhanced development of the B 29 with increased engine power and the airframe and tail improved for an increased air speed.. At no time did the B 50 serve with the RAF under the Boeing designation or any other name.
They got the mother of all piston engines, the 4 row R-4360. Pratt & Whitney R-4360 Wasp Major - Wikipedia