Volume 4, 1951 - The Arctic Circle - Home

High latitude navigation flights. By Moira Dunbar
A series of flights for the purpose of testing a number
of navigation instruments and techniques under arctic conditions
was carried out by the. Central Experimental and Proving Establishment
of the R.C.A.F. between 25 October and 3 November 1951.
Those taking part, other than the aircre\y, were: S/L J.G. Vlright,
R.C.A.F., operation commander; W/C D.A. Maclulich, R.C.A.F.;
S/L K.R. Greenaway, Dr. S.Z. Mack, and Miss M. Dunbar, Defence
Research Board; Dr. P.M. Millman and Dr. P.H. Se:son, Dominion
Observatory; Mr. F.M. Allan and Lt.-Col. E.D. Baldock, Surveys
and Mapping Branch, Department of Mines and Technical Surveys;
Miss V. V/ithington, Kollsman Instrument Company, New York; !lr.
Spencer Kellogg and Mr. Caesar Fragola, Sperry Gyroscope Company,
New York; and Mr. D.M. Potter, Potter Aeronautical Company,
Newark, N.J. These flights gave the two representatives of the
Surveys and Mapping Branch their first opportunity to use their
maps in the air, and the expcrience gained was considered very
valuable. Observations of the ground were made by these tw')
and by myself.
The aircraft was a North Star, captained by FIL R.
Johnson, and was based for the period of the flights at
Churchill, Manitoba. Among the instruments beiIlg tested were
the Kollsman periscopic sextant, the Sperry high latitude gyro,
the Rate Corrector Unit, the RG-DR computer for determining
bearings and distances, and the second model of the R.C.A.F.
twilight computer. The sextant, which is being adopted by
the R.C.A.F., is mcdified to give a direct reading of true
heading while the sun is under observation. It proved to be
very sE,tisfactory except for inadequate lighting of the bllbble
during twilight conditions. The Sperry gyro shoned great
accuracy, having a consistently low random wander rate thro:.1.ghout
the flights. A new plotting chart, which is the first ta
show the whole of Canada on one projectj_on, proved highly
satisfactory. This chart, which was produced to R.C.A.F.
specifications by the Departrllintof Mines and Technical Survays,
is drawn on a Lambert conformaI projection scale 1:3,000,000,
and is published in three sheets.
Three flights were made out of Churchill. The firs·~,
on October 26, was from Churchill to Yellowknife and back
towards Baker Lake, turning at the Thelon River aLd again at
Padlei and sa back ta Churchill. Hudson Bay was wide open,
and continued so throughout the operation. Only a small F.n::aunt
of pack ice was seen and the shore ice was barely starting ta