This calculator helps compare relative flexibility of spars. To use it, enter the distance, in inches, a 908-gram weight deflects when hung from the center of a 26-inch (66 cm) spar.
To begin, enter a deflection value and click Calculate. You can also optionally enter the outside diameter (O.D.) and inside diameter (I.D.) of the spars being compared. For solid rods, enter 0 for the inside diameter.
Note: The elasticity moduli used for "carbon" (17.7634892268) and "fiberglass" (7.2686776573) are not fixed physical constants. This calculator is intended as a guide and should be used in conjunction with real-world testing.
This page is written in PHP by Jesse Gersenson (see kite calculators) based on equations from Dave Lord's Scale Factor and a spreadsheet by Simon Craft
| spar (O.D/I.D) | weight (g/m) | deflection (in.) | scale factor |
| mm / mm carbon | 0.00 | ||
| mm / mm carbon | 0.00 | ||
| mm / mm fiberglass | 0.00 | ||
| mm / mm fiberglass | 0.00 | ||
| mm / mm ramen | 0.00 |