Introduction - Spar Strength Analyses


A spreadsheet was developed to aid in the sizing of carbon spars and wing joiners if joiners are used. Analyses are performed in various cells of the spreadsheet based on wing geometry and weight data entered by the user. The spreadsheet presupposes some degree of working knowledge of Excel and requires a working copy of Excel on the user’s computer.

Sheet 1 “Spar Sizing” contains all the input data cells and results while Sheet 2 “Instructions” provides brief instructions as to the steps involved in sizing the spar(s).

The analyses has been used by the author to design spars for 7 or 8 designs including F-1C like models, very high powered AMA Gas models, and even a few carbon spar replacements for NOS Gas designs. The designs have certainly proven adequate over 4 years of flying and various screw-ups which severely loaded the spars beyond normal flight loads.

If you have any questions or modify this spreadsheet I would appreciate hearing from you. Do not contact me for help in the basic use of Excel.


Bob Mattes
190 Hunters Pointe Dr.
Saint Charles, MO 63304