Today I had a test run up to check out the new aircraft starting battery. At around 60-70% RPM, there was a loud whoop type noise, the engine flamed out and was it at standstill within 10 seconds! The HP Cock was swiftly placed to the off position and I was left with wobbly knees and slightly tearful, also clueless as to what had just happened. After I gathered myself together and had a quick inspection, it became obvious that the engine had been FODDED with a fairly large piece of yellow cloth. Don't know where it came from, but there you go, it was there. The engine was extremely stiff to turn, impossible by hand and at this point I was convinced that the engine was a right off. I quickly took the viper back to the workshop, where an intelligent guess was that the last 4 stages and had effectively centrifuged the material outwards on to the outer compressor blade tips where they acted as friction between the outer tips and the compressor case. I administered a large quantity of WD40 in the hope that this would free it up and also by turning it over on the starter would expel the cloth, a bit of wishfull thinking unfortunately and the starter may have been damaged during this procedure, time will tell. Then after a conversation with Martin Hill of Fireforce fame, it was decided that the only option would be to remove the compressor case and remove the foreign material by hand. Pictured below is what we found.