PPRuNe Forums - View Single Post - Commercial Pilots who don't know about piston engines
Old 2nd Apr 2016, 23:32
  #229 (permalink)  
oggers
 
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I have only excused myself from providing the data on internet forums for ONE reason. Insufficient bandwidth.
Walter, engineers have been managing to compile and communicate the results of their tests since before the photocopier was even a thing. Every scientific paper is available online these days. We have broadband connections. You don't even have to reproduce the data because you can simply provide a link to wherever it is.

I have no duty to provide anyone with a graduate level education for free.
Respond or don't, we all participate freely here – no point complaining about it.

Moving on:

EGT does NOT affect valve temperature. We have hard data to prove that. The data came from a 1943 top secret NACA report done during WWII....valve temperature does NOT track EGT. This is 1943 data, not ours.
This is not correct. NACA-754 of 1943 shows clearly that valve temps track EGT. Figures 7a, b, and c and fig 8 all show it.

NACA754-fig7.jpg

The only exception to that was when the ignition timing was over advanced for the purposes of the test to 45BTDC. Even then, as the report points out “the fact that the temperature of the exhaust valve becomes greater than the temperature of the exhaust gas thermocouple is of no significance because the true exhaust gas temperature is greater than the thermocouple”.

We ran the test confirming this about 15 years ago.
...the NACA report has been declassified. It is in line with what is in the textbooks. Maybe it is time you declassified some data from 'your' test seeing as your conclusion is at variance with the NACA report you cite.
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