Figure wing area using formulas above by picking the wing shape that best matches your plane.
Wing loadings are figured by dividing the wing area of your plane by 144 to convert square inches to square feet. Then divide the weight of your airplane by your wing area in square feet. Wing area in sq. in./ 144 = wing area in sq. ft. Weight of model in ounces/wing area in sq. ft. = ounces/sq.ft.of wing loading.
The charts below provide a shortcut to figuring wing loading for those competition events that require a minimum wing loading such as those flown in SAM (Society of Antique Modelers).
To figure a minimum weight for a wing area other than those on the chart you divide wing area in square inches / 144 to get wing area in square feet. Multiply wing area in square feet by minimum weight in ounces per square feet desired which equals target minimum weight. Sq in. wing area /144 = ounces/sq ft. ; ounces/sq ft. x min ounces per sq ft desired = target minimum weight.
(example: a plane with 485 sq in of wing area and we want a target minimum wing loading of 20oz / sq ft. (485 sq.in. / 144 = 3.37sq. ft. x 20 oz. per sq.ft. = 67oz target minimum weight of airplane.)
| Minimun Weights At 8 oz/sq ft | |
|---|---|
| Sq. In. Of Wing Area | Weight in Oz. and lbs. |
| 144 | 8 oz. / .5 lbs |
| 288 | 16 oz / 1 lbs |
| 432 | 24 oz / 1.5 lbs |
| 576 | 32 oz / 2 lbs |
| 720 | 40 oz / 2.5 lbs |
| 864 | 48 oz / 3 lbs |
| 1008 | 56 oz / 3.5lbs |
| 1156 | 64 oz / 4 lbs |
| 1296 | 72 oz / 4.5lbs |
| 1440 | 80 oz / 5 lbs |
| 1584 | 88 oz / 5.5 lbs |
| 1728 | 96 oz / 6 lbs |
| 1872 | 104 oz / 6.5 lbs |
| 2016 | 112 oz / 7 lbs |
| Minimun Weights At 10 oz/sq ft | |
|---|---|
| Sq. In. Of Wing Area | Weight in Oz. and lbs. |
| 116 | 8 oz. / .5 lbs |
| 231 | 16 oz / 1 lbs |
| 346 | 24 oz / 1.5 lbs |
| 462 | 32 oz / 2 lbs |
| 576 | 40 oz / 2.5 lbs |
| 692 | 48 oz / 3 lbs |
| 807 | 56 oz / 3.5lbs |
| 922 | 64 oz / 4 lbs |
| 1037 | 72 oz / 4.5lbs |
| 1152 | 80 oz / 5 lbs |
| 1268 | 88 oz / 5.5 lbs |
| 1383 | 96 oz / 6 lbs |
| 1498 | 104 oz / 6.5 lbs |
| 1613 | 112 oz / 7 lbs |