A number of single engine conventional aircraft are studied to investigate the possibility of applying statistical methods to the problem of aircraft weight estimation.It is shown that the statistical treatment is definitely useful.It is also shown that, without proper care and judgment, such a statistical treatment leads to somewhat misleading results.The need for structural and aerodynamic training and experience together with essential weight estimating experience is evident.Such experience is requisite to arriving at proper weight estimates when basing these estimates upon the weights of aircraft which have previously been designed and built.
It was hoped that the effects of all of the important aerodynamic and geometric parameters upon aircraft weight would be found from this study of successful single engine aircraft.It was further hoped that the results of this study would be applicable to the difficult problem of estimating the weight of new aircraft.The number of aircraft in the sample for which pertinent information was available was not large enough to permit the evaluation of the effects of all of the parameters although most of the important parameters and their essential effects have been indicated.Lack of complete information due to the restricted or confidential nature of the data was one of the most troublesome handicaps.The latter problem of obtaining weight estimating procedure has, however, been solved since satisfactory weight estimating formulas have been developed for use in basic design weight estimates.
It is this latter result for which the entire study was made. That is, the study was initiated to offer assistance to practicing preliminary design engineers by providing usable information concerning the effects of such factors as gross weight, load factor, and wing span upon aircraft weight.Such information should be invaluable to assist in arriving at the optimum aircraft design with respect to performance, maneuverability, and utility.
All the useful estimating formulas are summarized on page 43.Also included are the calculated probable errors of estimate.
