Cart Shopping Cart My Store Account Orders Downloads Shopping Cart Remove item Thumbnail image Product Price Quantity Subtotal × 2. Airplane Weight and Balance Control $20.00 2. Airplane Weight and Balance Control quantity $20.00 × 8. A Practical Method for Wing Weight Estimation $20.00 8. A Practical Method for Wing Weight Estimation quantity $20.00 Coupon: Apply coupon Update cart Available coupons (Click to apply). Cart totals Subtotal $40.00 Tax $0.00 Total $40.00 Proceed to checkout