Aristo Aviat 610 & 615 (1955): the DR2 Dreieckrechner evolves

In the mid-1950's, Dennert & Pape released two new versions of Siegfried Knemeyer's Dreieckrechner: the pocket-sized 610 and the full-sized 615. The major improvement in the revised design involved combining the linear and logarithmic scales for wind triangle calculations onto the same side of the device. In this first of two videos on the Aviat 610 & 615 (see part 2 here:    • Aristo Aviat 610 & 615 (1955) Part 2: the ...  ), we look at the wind side of the device and solve a simple flight planning wind triangle (for more details on the law of sines solution, see the DR-2 video:    • DR2 Dreieckrechner, Dennert & Pape (Part 1...  ). We also discuss a few differences between the 610 and the 615 models, namely the omission of flight levels from the cruise altitude tables, and interestingly, the difference between semicircular (hemispherical) and quadrantal rules for choosing appropriate cruising altitudes. In the lesser known "quadrantal" system, the compass is divided into four sections, instead of two halves, with each section having a unique rule for determining the appropriate cruising altitude. 00:00 – 1. Introduction, 00:20 – 2. Device Size, Branding, and Construction 02:27 – 3. The revised wind side 04:20 – 4. Solving the wind triangle via the law of sines 06:17 – 5. Cruising Altitude Tables 07:36 – 6. Semicircular vs Quadrantal Cruising Altitude Rules 09:46 – 7. Conclusion Notes: When discussing semicircular cruise altitudes, I quickly say northeasterly rather than "North and Easterly" (same goes for "South and Westerly"). Also, the quadrantal rules were: 000° to 089°: Odd thousands of feet 090° to 179°: Odd thousands plus 500 feet 180° to 269°: Even thousands of feet 270° to 359°: Even thousands plus 500 feet #airnavigation #aristo #aviat #610 #615 #Dreieckrechner #DR2 #math #history #pilottraining #sliderule #quadrantalrule #semicirularrule #hemisphericrule