Head winds are easier to ride into and the fairing works like a sail in tail winds. High speeds are easily attained when descending, good brakes are essential on curved downhills. At those speeds the air resistance is becoming very high and to achieve a difference that big without pedalling indicates the efficiency gain of the fairing. It has also been used off-road and has survived gorse bushes, dry willow branches and being thrown into and dragged out of blackberry bushes. A minor slide into the undergrowth at the side of a gravel road was less damaging than expected due to the fact that I was able to tuck behind the fairing while sliding into the brush.
Single track is interesting but with the right set up it causes no problems.
I have clearance that allows me to stand up on steep hills and throw the bike around on rough tracks. The second fairing I built this for a LWB recumbent of my own design, fitted with above-seat steering. The fairing was easy to make. A simple long flat sheet was TyRapped to the big ape hanger bars and the front edge was pulled into a curve. The curve was held in place by using a former made from plastic sheet and 25mm polystyrene in a sandwich construction.