Anyone tried using elliptical wing for small UAS (weight ~3.5 kg, wingspan ~6 ft). In theory it seems efficient, however in manned aircraft it is not used due to manufacturing/cost issue. However, manufacturing may not be a big issue for small UAS. Please share your experience/opinion.
Not an expert but I've found that the gains are small overall and may not be worth the extra effort in construction.
If a an electric UAS can fly 2 hrs then a 5% inprovement in lift distribution may only result in a 2% decrease in perceptible drag, thus increasing it's flying time by 2.5 mins. Other factors can have a much greater impact on efficiency for example adding winglets to reduce tip vortices, or enhanced drag reduction or powertrain/battery optimizations. Also elliptical wings can stall easily without warning.