SOFsimr Posted January 27, 2010 Share Posted January 27, 2010 New to the site... Working for Lockheed Martin and I have a basic question on the torque indication for the -15 engines.... We accomplished a flight test recently and we had recorded the electrical signal off of the torque assembly and converted it to a Torque indication based on an equation supplied by Marietta.. What we found was the instrument always read about 10% on the top end less than our recorded value.. My question is has anyone done a digital vs mechanical inspection to see how accurate the mechanical gauge is as a digital one.. Also how accurate is the calibration to these instruments (how close are they to what we think is the right number).. I've seen the calibration instructions and they seem like they could easily be off by a couple hundred inch/lbs.... Thanks for any information.... Quote Link to comment Share on other sites More sharing options...
NATOPS1 Posted January 28, 2010 Share Posted January 28, 2010 (edited) Not sure this will help but here goes... You recorded the electrical signal... What did you measure? Voltage? Time span? Or ?? Converted the signal based on an equation supplied by Marietta.. Still have this equation? I would be interested in the method used. If the instrument reads 10% off at the top end of 19,600 that’s 21560 so we need to look at a few interface points that could effect this error. The Torque gauge calibration is easy to do in a manner that will induce errors. 1. Torquemeter Calibration number- To be accurate the number stamped on the torquemeter must be used in the calibration process. A catch all number is 29850 (1st variable) Depending on part number installed add or subtract 380 in lbs to/from this shaft calibration number. (To illustrate we have a torquemeter here with a Cal # of 29580.) Also if the parameters used to calibrate the gauge are incorrect IE: Outside Air Temp Pressure Altitude RPM Wind All variables used to set the Min torque and once set (if done right) the indication has a tolerance of +/- 50 in lbs. So add them up and you could see a significant difference.... I assume you are asking if there has been a digital vs mechanical comparison of the indications to check accuracy of each. I don’t know for sure but I would have to say yes due to the engine being the same, the wing being the same (torque limited), ETC... Edited January 28, 2010 by NATOPS1 Quote Link to comment Share on other sites More sharing options...
MAXTORQ Posted January 28, 2010 Share Posted January 28, 2010 All of our 96's had the digital gauges removed except for oil cooler flap position . Torq, rpm, FF, Eng and GB all gone. I beleive it's because of this very reason. Quote Link to comment Share on other sites More sharing options...
NATOPS1 Posted January 29, 2010 Share Posted January 29, 2010 (edited) I think those were removed due to supply issues..... I think they are discussed on a thread here somewhere....... LCD INST Found it... http://herkybirds.com/forums/showthread.php?t=1327 Edited January 29, 2010 by NATOPS1 Quote Link to comment Share on other sites More sharing options...
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