Were Sorry, Readers —but with all the misinfomation, this must be repeated: JSF: After more than 2 weeks of espousing daily hope that 4 JSFBs would make a historic debut in the UK, the Pentagon has finally announced that there will be no show even though the fleet has been approved for limited flight [i.e. for 3 hours, after which the engine has to be checked again - VNC]. The decision came at 1900 hrs Farnborough local time, after the crowds had left, barring a bevy of reporters who have been reporting daily on the situation from asking questions on the decision and whether more technical insight has come to light about the mishap. What they did get is that on July 14, USN and USAF allowed return to flight with limited clearances. But: It is not clear what portions of the envelope are limited. One source close to the program suggested the g loads will be restricted while work is ongoing in the investigation. Nor has been said whether any JSFs have actually flown since the limited clearance was given. It is also unclear whether the aircraft involved in the fire will be a total loss. It is also not clear when the next opportunity for a show will occur, given the testing schedule; nor whether deployment plans will allow for another attempt at an international debut soon. A demonstration at the Paris air show next year is unlikely; US officials are skittish about basing stealthy aircraft in France. Pentagon officials said that the F135 engine fire was the result of excessive rubbing between the third stage fan of an integrally bladed rotor and an abradable strip lining the casing of the engine. Some rubbing is acceptable, but AF-27 experienced extreme friction, creating excessive heat that eventually caused the engine to burst into flames. Program XO Bogdan said that data from inspecting all 98 operational engines indicate that the problem is not endemic to the entire fleet. We have to add here that there is no way Bogdan or anyone else can know so, as it is not (yet) clear why and how the rubbing in the one plane occured. Anyway: who had the wicked idea to line the casing of a jet engine with an abradable strip that can be hit by the blades of a rotor? And how can abrasion around one forward rotor tear the engine apart or cause the engine to burst into flames, when teh earliest reports said that the fire broke out at the rear of the aircraft?
Posted on: Thu, 17 Jul 2014 08:44:48 +0000