clovie Posted January 16, 2013 Share Posted January 16, 2013 Hi there......just wonder if synchrophaser has related with engine not achieve 95%take off power Quote Link to comment Share on other sites More sharing options...
clovie Posted January 16, 2013 Author Share Posted January 16, 2013 Can the synchrophaser cause the engine under power Quote Link to comment Share on other sites More sharing options...
Cheesehead Posted January 17, 2013 Share Posted January 17, 2013 No it can not. If your only getting 95% power at takeoff, either you have a bad turbine or compresser, i.e blades ware and tare, or you have some bleed air leaks. Need to check performace. Oat, pressure alt. torque, tit, and fuel flow. Then if all is done, man on the stand for bleed airl lk cks. Throttle alignment and T.D amp Test ( y-box). could also have dirty compressor so a compressor wash may be in order. Quote Link to comment Share on other sites More sharing options...
Lkuest Posted January 18, 2013 Share Posted January 18, 2013 Can the synchrophaser cause the engine under power The objectives of the synchrophaser are speed stabilization, and when a master propeller is selected, it establishing phase angle relationships. It accomplishes both of those objectives by influencing RPM. By asking if the synchrophaser can cause an engine to fail to make power, I am assuming you have an RPM problem since that is what the synchrophaser is designed to change. Our tech data states that an error of 1% RPM can cause an error of efficiency of .45 to .9% efficiency. The synchrophaser can in fact cause an engine to be low power under two circumstances: Engine efficiency is very close to 95%, and RPM is greater than 100%, or the synchrophaser is causing an overspeed of greater than 103.5% under stable throttle position and the fuel control fuel governor is cutting fuel. In either case, you would be checking efficiency at an RPM other than 100%, which you must not do if you wish to ensure accuracy. Your question also makes me assume that, when checking efficiency, your efficiency is good when propeller governor is in mechanical, and it is bad when your propeller governor is in synchrophasing mode. Again, you should only check engine efficiency at 100% RPM. Just like Cheesehead has mentioned, efficiency depends on many factors, so if your engine is that close to 95% that engine RPM is weakening the engine, you may have other problems. Efficiency is a function of compressor and turbine efficiency. Turbine operating hours, damage, and thermocouple indication all affect turbine efficiency. The compressor's job is to provide the turbine with an adequate air supply. Whatever affects the air supply to the turbine can ruin the efficiency. Think high operating hours, blade damage, air leak (bleed air ducting, anti-icing, compressor case splitline/seal leakage). Also, ensure that your torque and TIT indication systems are accurate or your efficiency numbers will be inaccurate. A 200 in/lb error in torque indication will lead to a 1% error in efficiency. A 5 degree error in TIT indication will equal a 1% error in efficiency. Also, make sure your pressure altitude and outside air temperature readings are accurate. Quote Link to comment Share on other sites More sharing options...
Steve1300 Posted January 18, 2013 Share Posted January 18, 2013 Personally, I would not bother with a TD system tester to fix a low power problem. If you are getting your TIT for the check, the amp is not causing your problem. As previously posted, if you are getting 100% rpm, your prop is not causing your problem. I have yet to actually work a low power engine that a turbine caused without having other indications of a problem. With an engine that appears normal except for performance numbers, it has been caused by compressor issues or leaks. Sometimes, it was something simple but we wasted a great deal of time finding it. Live and learn! Quote Link to comment Share on other sites More sharing options...
NATOPS1 Posted January 18, 2013 Share Posted January 18, 2013 Is this reported by your aircrew or maintenance during a check? If by your aircrew the bleed air regulator valve may be regulating high (too much air out results in low torque for set TIT) and/or the or compressor (if you have open/closed bleed air valves) could be stronger.... If by maintenance the factors Lkuest previously listed could be the issue and as stated RPM is very important in calculating Performance. also check the anti ice for the bad engine... Quote Link to comment Share on other sites More sharing options...
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