NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Early methods of air navigation
From: Gary LaPook
Date: 2014 Nov 21, 10:29 -0800
From: Fred Hebard <NoReply_Hebard@fer3.com>
To: garylapook@pacbell.net
Sent: Friday, November 21, 2014 9:21 AM
Subject: [NavList] Early methods of air navigation
From: Gary LaPook
Date: 2014 Nov 21, 10:29 -0800
The book, Precision Astrolabe, by Francis M. Rogers, (1971) is the book you need but I don't know if it is available anywhere. It discusses everything you are asking about, see the excerpt I posted several years ago. All the international airlines were using celnav then and most used the Kollsman periscopic sextant, developed in 1947, because all the airliners built in the U.S. (Constellations, DC-6s, DC-7s, DC-8s and B-707s) came with the sextant mount for it.
He participates in a flight on a TAP (Porteguese ailine) on June 24, 1970 and describes the method which used HO 249 and the Air Almanac and the Kollesman sextant.
gl
From: Fred Hebard <NoReply_Hebard@fer3.com>
To: garylapook@pacbell.net
Sent: Friday, November 21, 2014 9:21 AM
Subject: [NavList] Early methods of air navigation
The discussion of the Brown-Nassau CN Plotter brought to mind the following question. What methods did the early pioneers of trans-Atlantic flight use for navigation, such as Alcock and Brown? Brown was the navigator on that flight. They made landfall near their intended destination. Running down a line of latitude would be a clear choice, but how measure the latitude? They flew at low elevations, so perhaps using the actual horizon? Dip scales as the square root of elevation. The error for being 50 feet off in elevation is less than two minutes of arc at 200 feet. In contrast, Admiral Coutinho installed levels on his Plath in 1919. Had the British? Then there is RDF, which was available in the U.S. by the Point Honda disaster. Those are some guesses. What does the documentary evidence say? Thanks. Fred Hebard mbiew---.net
