(42S) Rate of Climb and Descent, Head and Cross Winds - Printable Version +- HP Forums (https://www.hpmuseum.org/forum) +-- Forum: HP Software Libraries (/forum-10.html) +--- Forum: General Software Library (/forum-13.html) +--- Thread: (42S) Rate of Climb and Descent, Head and Cross Winds (/thread-14345.html) (42S) Rate of Climb and Descent, Head and Cross Winds - Eddie W. Shore - 01-11-2020 03:35 PM Rate of Climb and Descent The solver CLIMB creates a solver of the equation: ROC = TAS * ALT / √(DIST^2 + ALT^2) ROC: rate of climb, usually in ft/min TAS: true airspeed of the airplane, usually in knots ALT: (vertical distance) the change in elevation, take into the account the height of your airplane, the height of the mountain or obstacle to be cleared plus desired clearance height, usually in feet DIST: (horizontal distance) distance to the mountain or obstacle to be cleared For the solver to accurate, you must keep the units consistent (feet or nautical miles for distance, ft/min or knots for speed and rate of climb) Conversion factors: 1 knot = 101.269 ft/min 1 nautical mile = 6076.12 ft HP 42S/DM42/Free42 Solver program CLIMB ﻿ Code: ``` 00 { 61-Byte Prgm } 01▸LBL "CLIMB" 02 MVAR "TAS" 03 MVAR "ALT" 04 MVAR "DIST" 05 MVAR "ROC" 06 RCL "TAS" 07 RCL× "ALT" 08 RCL "DIST" 09 X↑2 10 RCL "ALT" 11 X↑2 12 + 13 SQRT 14 ÷ 15 RCL- "ROC" 16 .END.``` Example: TAS = 90 knots = 9114.21 ft/min ALT = 5000 ft DIST = 16 nautical miles = 97217.92 ft Solve for ROC: 468.1328 ft/min Link to download (climb_solver.raw): https://drive.google.com/open?id=1Zd_Gyj8RJ_ehaozjBB9hfP5Gj_s1QBAS Head Winds and Cross Winds The program WINDS calculates the head wind and cross wind (right is positive, left is negative) given the following inputs: D: reported wind direction HDG: heading of the aircraft V: compass magnetic variation, if any The directions are entered in degrees, measured from true north, clockwise K: reported wind velocity Head wind: HW = K cos(D - HDG - V) Cross wind: CW = K sin(D - HDG - V) We can use the polar to rectangular conversion function with the following convention: θ = D - HDG - V r = K HP 42S/DM42/Free42 Program WINDS Code: ``` 00 { 79-Byte Prgm } 01▸LBL "WINDS" 02 DEG 03 "WIND DIR?" 04 PROMPT 05 "HEADING?" 06 PROMPT 07 - 08 "COMP VAR?" 09 PROMPT 10 - 11 "WIND VELOCITY?" 12 PROMPT 13 →REC 14 "Y:CROSS X:HEAD" 15 AVIEW 16 STOP 17 RTN 18 .END.``` Example: Wind Direction: 30° Heading of Aircraft: 350° No compass adjustment Wind Velocity: 20 knots Results: Y: cross winds: 12.8558 knots (from the right) X: head winds: 15.3209 knots Link to download (winds_head_and_cross.raw): https://drive.google.com/open?id=1RoIKgbnAWmT36pLn6MHMqKXmUw19e3wh Source: "Rate of Climb and Descent" and "Head Winds and Cross Winds" HP 65 Aviation Pac 1. Hewlett Packard, 1974 Blog link: http://edspi31415.blogspot.com/2020/01/hp-42sdm42free42-rate-of-climb-and.html