Before he retired he worked for an engineering company that did lots of experimental stuff for the MOD and one of this companies specialities was Hot Metal Spraying,(how this came to light was him enquiring how the Classic engine re-build was progressing and me telling him how badly the End & Centre Plates were scored and whether they had enough metal for a skim and regrind)He then mentioned the Hot Metal Spray technic,I said the "jury was still out" weather it worked or not on Rotories as it tended to "lift" "That's because it wasn't sprayed on thick enough" he explained,that,evidently,is the secret,skim off lots of the old metal,spray on even more new metal,then skim off the new metal back to the original factory spec,a quick coat of Molly and hey presto
nice new End & Centre Plates 
.Another little "Job" was perfecting a Diesel Rotory?? The MOD threw shed loads of money at this project(all very hush hush)and the end product was a Diesel Rotory for the latest Challenger Tank
,and very successful it was too,Went like the clappers,very reliable and easy to maintain,but quite thirsty I should imagine(pollution?what pollution 
)Next time I see this guy I will have to ask him about Power output?was it a "V" engine? and many Ltrs was the engine size?(modern 48ton artics have 10/12 ltr V8's pumping out 600+bhp),and seeing a a Challenger Tank weighs in at about 60ton I expect we are looking at about 20ltr and 1000 bhp? pure speculation of course,but its all harmless fun Very HappyJ.B.