Saturday, 14 January 2012

Engine Inlet Screens

Engine Inlet Screens

Pictures show that Labradors, when purchased, did not have engine inlet screens. Whether Voyageurs did or did not is not clear. In any case, both variants were fitted with the same conical shaped screens early in their service life.  The purpose of the screens was to prevent debris from being ingested into and damaging the engines.  When looked at from head on it is interesting to note that the inlets screens are neither exactly conical in shape nor symmetrical when comparing left with right screens.  In part, the asymmetrical shape is because the sync shaft tunnel is not centered on the top of the fuselage.

Note that there are no engine inlet screens on aircraft 401 which still has American registration on the right side. Photo via Pat Mercer.
The differences in the shapes on either side are evident in this picture.  Photo - Randy Brown collection.
 In the spring of 1989 as my time on Labradors was ending, there were discussions regarding new engine inlet screens.  From what I can recall, it seems the conical screens while effective against foreign object damage (FOD) had a tendency to ice up enough to reduce airflow to the engines in certain weather conditions.  I believe the larger screens were thought more likely to negate the potential for engine failure from weather related conditions.!

New screens as installed at Arnprior. Photo via Pat Mercer
Side view of the new screens. Also of note is the flat tank brace of a Labrador. Photo courtesy of Jeff Wilson
Pre SARCUP Voyageur 308 side view showing old style inlet screens. Photo courtesy Patrick Martin.

SARCUP Voyageur with top hat shaped engine inlet screens. Note as well the rod style tank braces. Photo courtesy Patrick Martin
Top hat engine inlet screens on the workbench. Photo courtesy Scott Hemsley

Note the backside of the screens installed on this unidentified Labrador are  not flush to the airframe at the  back end. Photo courtesy Scott Hemsley

Labrador 401 wearing the CEPE crest on the sponsons has screens installed. DND Photo

Voyageur 407 with screens installed.

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