----- Original Message ----- From: "Orma" <o...@aviation-mechanics.com> To: "KRnet" <kr...@mylist.net> Sent: Thursday, November 18, 2004 2:25 PM Subject: KR> Turbo Trouble
> Hello Net > As I removed the turbo, I also got an Oh Sxxt, when I noted that the impeller has taken an impact and that it will have to be replaced. With the revflow wide open as in take off, there is nothing to stop some pretty large objects from reaching the impeller. Orma; Sorry I have no advice on the pressure problem. But, based on a career that included repairs on aircraft turbine engines, gas turbine compressors, and aux power units you may be able to repair your turbine/impeller. If you have the tech data to give you the metal composition, and depending on location on the impeller, you may be able to weld repair the part. At the Naval Aviation Depot that I worked at we would do weld repairs on the contour portion up to 0.050 inch deep and on the tip portion up to 0.250 inch. The sides of the weld were hand ground and finished to the same thickness as the original part. The wheel was then ground back to the original blue print contour. If your wheel has not rubbed on the casing then your wheel should be per print for all practical purposes. You could try making a template from an adjacent impeller blade and hand finish the welded blade to match. You may have to do post weld heat treat and balance. DO AN NDI. If you are missing a really big chunk, you lose. Check out your turbine wheel for damage. If you have axial cracks in the hub area between the blades do not panic. These are usually stress relief cracks and will not continue to grow. We saw a lot of them on GTC100-54 and GTC 95-2 turbine wheels. Some appeared in less than 10 operating hours. One last thing to consider. Treat the turbine as you would the engine by avoiding thermal shock. The worst thing you can do is to start the engine, run at full power for a short duration and then shut the engine off quickly. This is hard on the turbine and the oil will not be able to do its real job of post engine shut off lubrication. Our GTC engines actually had a built in oil reservoir to keep the bearings lubricated at all times. Bob Bought KR2S in boat stage. Building aircraft mfgring facility.
