On Wed, 13 Jun 2018 07:40:51 -0500,Mitchell Holman
1
A-20 049.jpg
Title: Servicing [an] A-20 bomber, Langley Field, Va.
Creator: Palmer, Alfred T., photographer
Title from FSA or OWI agency caption.
Date Created/Published: 1942 July
Original: 7707x6271 TIF - 138MB
Call Number: LC-USW36-203
"Additional information about this photograph might be available
through the Flickr Commons project"
http://www.loc.gov/pictures/item/2017878472/
The Library of Congress
"Taken circa 1939"
-marley1027
Looks like they are rotating the propeller. That is commonly done with
radial engines prior to flight. The purpose it to prevent damage to
the engine from hydra locking, a condition caused by oil collecting in
the lower cylinders.
Dave
-curtissfortysix
And then they discovered why all the rods were getting bent and
failed. The starter with clutches pretty much cured that problem.
http://www.flickr.com/photos/library...ess/2179066177