DM42

Programs for calculators: HP-42s, DM42 or Free42

This repository contains some programs I made in various fields: maths, aviation, etc.

Programs

Programs are organized by folder named by fields. For each program, there is a folder which contains a binary raw file and a text file showing the instructions of the program. The text file is decoded with the help of .

Maths

norm_vector/NORMVEC computes the norm of a vector:

• After launching the program, the execution halts in order to get the input.
• Type the value for X component in X register and then select X component in the variable menu.
• Repeat previous step for Y and Z components.
• Type R/S to complete the course of the program
• The norm is computed in the X register so you may use it for additional calculations.

projection_segment/PROJ projects a segment to X and Y axis and provides their projected length onto these axis:

• After launching the program, the execution halts in order to get the input.
• Type the value for the length of the segment in X register and then select LENG component in the variable menu.
• Type the value for the angle between the segment and X axis in X register and then select ANGL component in the variable menu.
• Type R/S to complete the course of the program
• The Y projected length is stored in Y register and the X projected length in X register.

Aviation

aviation/DR34 computes the weight and balance of an aircraft. It is applicable for an aircraft with 2 rows of seats R1 and R2 and each row can have 1 or 2 seats. The total mass on row 1 is MR1, same for row 2 with MR2. If the mass on row 2 should not be considered, leave it to 0. The units does not matter as long as they are all consistent. The mass of luggages is MBAG and it is considered there is only one place for luggages. One fuel tank is always considered and an optional fuel tank can be used. For wing tanks you can add their masses as long as they have the same arm. Every time you launch the program, variables are set to 0 to avoid considering previous input in case you run the program several times. Some parameters are hard coded for Robin DR-300 and DR-400 in order to have less typing and less variables (it is recommended to hard code those suitable for your plane):

• arm for row 1: 0.41 units
• arm for row 2: 1.19 units
• arm for luggages: 1.9 units
• arm for fuel tank 1: 1.12 units
• take-off arm as a percentage of allowed arm stroke (0.359 units), meaning from front limit (0.205 units) to aft limit (0.205 + 0.359 units).

How to use the program:

• After launching the program, the execution halts in order to get the input.
• Type the value for empty mass in X register and then select MV in the variable menu. Same for empty mass arm XV.
• Type the value for the mass on seat row 1 in X register and then select MR1. Same for the mass on row 2 MR2 if applicable.
• Type the value for the mass of luggages in X register and then select MBAG if applicable. Same for the mass of fuel tank 1 MC1.
• Type the value for mass of fuel tank 2 in X register and then select MC2 in the variable menu, if applicable. Same for its mass arm XC2.
• Type R/S to complete the course of the program
• The total mass is stored in Y register and in MD and the take-off arm as a percentage of arm stroke is stored in X register and XD. So XD should be between 0 and 100% to be compliant. Note that only the integer part is kept for XD.

aviation/ESPY computes the height of cumulus base based on temperature and dew point. This is an approximation based on Espy formula. Units: temperatures in Celsius degrees and height in feet.

• After launching the program, the execution halts in order to get the input.
• Temperature is asked. After input press R/S to continue.
• Dew point is asked. After input press R/S to continue.
• The height of cumulus base is in X register.

Impact

These programs helps to compute impactor displacement or efficiency in the event of an impact driven by mass and initial velocity. The relationship is: energy = efficiency * load * displacement. Load can be replaced by acceleration * mass * g. Units are: J for energy, kN for load, mm for displacement and g for acceleration. Efficiency is between 0 and 1.

impact/HI1 computes the necessary displacement of the head for a head impact, as per ECE-R21 or FMVSS201, based on energy to be absorbed with the maximum acceleration and a given efficiency. The mass of head is 6.8 kg. How to use the program:

• After launching the program, the execution halts in order to get the input.
• Type the value for energy in X register and then select ENER in the variable menu. Same for efficiency EFFY and acceleration ACCL.
• Type R/S to complete the course of the program
• The displacement is stored in X register and in DISP.

impact/HI2 computes the efficiency under the same relationship as HI1 and the program works in the same way.

impact/KNE1 computes the necessary displacement of the knee impact considering a single leg thrown with initial velocity onto a part. How to use the program:

• After launching the program, the execution halts in order to get the input.
• Type the value for energy in X register and then select ENER in the variable menu. Same for efficiency EFFY and load LOAD.
• Type R/S to complete the course of the program
• The displacement is stored in X register and in DISP.

impact/KNE2 computes the efficiency under the same relationship as KNE1 and the program works in the same way.