Historically, human powered aircraft (HPA) have been known to have very large wingspans. For example, the Gossamer Albatross has a wingspan of 96 ft. greater than that of a Boeing 717 which is a comme..
Historically, human powered aircraft (HPA) have been known to have very large wingspans. For example, the Gossamer Albatross has a wingspan of 96 ft. greater than that of a Boeing 717 which is a commercial airplane with the capability of carrying over 100 passengers. The main reason why HPA have such large wingspans is for aerodynamic performance. During low speeds, the predominant type of drag is the induced drag which is a by-product of large wing tip vortices generated at the wing tips during slow flight at higher coefficients of lift. In order to reduce this phenomenon, higher aspect ratio wings are used which is the reason behind the very large wingspans for HPA. Due to its high Oswald efficiency factor, the boxwing configuration is presented as a possible solution to decrease the wingspan while not affecting the aerodynamic performance of the airplane. The new configuration is analyzed through the use of VLAERO+, a commercial vortex lattice method analysis software, after proper calibration procedures are applied. The parasitic drag was estimated using empirical methods based on the friction drag of a flat plate. The structural weight changes in the boxwing design were estimated using “area weights” derived from the original Gossamer Albatross. The two aircraft were compared at a cruise velocity of 22 ft/s where the boxwing configuration showed a net drag reduction of approxiametly 0.36 lb, which can be deduced from a decrease of 0.81 lb of the induced drag plus an increase of the parasite drag of around 0.45 lb. Therefore, for an aircraft with approximately half the wingspan, easier to handle, and more practical, the drag is essentially reduced by 4.4%.
