Joe Broady
Airman 1st Class
- 105
- May 30, 2019
A collection of the USAF magazine Flying Safety from the 1950s is online at archive.org.
Flying Safety
They also have issues of the SAC magazine Combat Crew from the 1970s/80s.
Combat Crew (archive.org)
Google has a smaller collection of Combat Crew, but it includes issues from the 1950s/60s.
Combat Crew (Google)
In that last collection I found a 1957 article on KC-97 engine reliability. "During a single year SAC surveyed the removal of 291 engines from KC-97 tankers. Only 12 were removed because they had reached the maximum time allowable." All the others failed prematurely! A leading problem was main / master bearing failure due to improper desludging and oil screen cleaning, plus high rpm / low manifold pressure operation. Another was exhaust valve failures, generally due to excessive head temp. ("CHT gauges are frequent liars, so pull ground static checks on CHT vs. OAT gauge calibration every two weeks or so.") Burned pistons were another big problem, generally caused by preignition / detonation.
Keep Your Horsepower Groomed
Also from 1957 is this hint on why you should not mark exhaust stacks with a pencil.
Pencil Marked Stacks
I was trained to not make pencil marks on aircraft structure because the electrochemical potential of graphite is much different from the metals used in aircraft. It sets up conditions for corrosion, same as when you have dissimilar metals in contact. One time I tested that by washing out a tuna can and scribbling with a pencil on the bottom of the can. I left in in the sump of an evaporative cooler all summer. But when I drained the cooler there was no corrosion on the can! Good galvanizing, I guess.
Flying Safety
They also have issues of the SAC magazine Combat Crew from the 1970s/80s.
Combat Crew (archive.org)
Google has a smaller collection of Combat Crew, but it includes issues from the 1950s/60s.
Combat Crew (Google)
In that last collection I found a 1957 article on KC-97 engine reliability. "During a single year SAC surveyed the removal of 291 engines from KC-97 tankers. Only 12 were removed because they had reached the maximum time allowable." All the others failed prematurely! A leading problem was main / master bearing failure due to improper desludging and oil screen cleaning, plus high rpm / low manifold pressure operation. Another was exhaust valve failures, generally due to excessive head temp. ("CHT gauges are frequent liars, so pull ground static checks on CHT vs. OAT gauge calibration every two weeks or so.") Burned pistons were another big problem, generally caused by preignition / detonation.
Keep Your Horsepower Groomed
Also from 1957 is this hint on why you should not mark exhaust stacks with a pencil.
Pencil Marked Stacks
I was trained to not make pencil marks on aircraft structure because the electrochemical potential of graphite is much different from the metals used in aircraft. It sets up conditions for corrosion, same as when you have dissimilar metals in contact. One time I tested that by washing out a tuna can and scribbling with a pencil on the bottom of the can. I left in in the sump of an evaporative cooler all summer. But when I drained the cooler there was no corrosion on the can! Good galvanizing, I guess.
