(41CV) Helicopter Weight Estimate

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An extract from Computer Program Analysis of Helicopter Weight Estimate Relationships Utilizing Parametric Equations, Rudolph T. Schwab (CPT USAR), Naval Postgraduate School, Master's Thesis, JUN 1983, 61 pages

"ABSTRACT
This thesis gives the user of an HP-41CV handheld programmable calculator or the IBM 3033 computer, acceptable results of helicopter system weight estimations during the preliminary design phase.
The computer program consists of several subroutines and will compute system weight estimates according to Military Standard 1374A. Three categories of military helicopters can be designed; observation, utility, and cargo. Detailed knowledge of helicopters is not required.
…
APPENDIX A: HP41-CV COMPUTER LISTING … 26
A. OBS SUBROUTINE LISTING … 26
B. UTIL SUBROUTINE LISTING … 28
C. CGO SUBROUTINE LISTING … 30
D. OUTPUT SUBROUTINE LISTING … 32
E. INPUT SUBROUTINE LISTING … 33
F. LISTING OF CALCULATOR DISPLAYS … 34
G. STORAGE ALLOCATIONS … 35
…
APPENDIX C: HP41-CV EXAMPLE PROGRAMS … 47
A. OBS SUBROUTINE PROGRAM … 47
B. UTIL SUBROUTINE PROGRAM … 49
C. CGO SUBROUTINE PROGRAM … 51
…
I. INTRODUCTION
A. BACKGROUND
The estimation of the weight of a helicopter is an essential preliminary step in design procedure. The aerospace industry uses large complex computer programs with hundreds of inputs in order to obtain, the predicted weight of the various helicopter systems. This, of course, is the most accurate method in determining precise weights needed in actual design and construction. However, these programs require a detail knowledge of the components and materials to be used, which are not normally available outside the industry. Therefore, another method using the HP41-CV hand held calculator or the IBM 3033 was undertaken that would give acceptable results while providing instantaneous solutions. To date, no known programs of this type have been designed for the HP41-CV or IBM 3033.
B. GOALS
The objective of this study is to provids a self prompting, alpha-numeric computer program for helicopter weight estimates. In addition it is to be used by Aeronautical Engineering students at the Naval Postgraduate School enrolled in the Helicopter Design and Advanced Helicopter Design courses.
II. APPROACH TO THE PROBLEM
The basic approach was to write a computer program on the IBM 3033 using Fortran IV and converting this program to HP41-CV usage. The program consists of the following subroutines:
A. Input
B. Output
C. Observation
D. Utility
E. Cargo
This method greatly reduces the amount of computer memory required. Subroutines Observation, Utility, and Cargo are independent of each other and depend only on the Input and Output subroutines.
These subroutines use parametric equations derived from the best curve fit of the various system weights. Detailed knowledge of helicopter weights is not required, however, a basic knowledge of helicopter characteristics and aerodynamics, along with proficiency in either the IBM 3033 or HP41-CV is required."

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