High tech wheel pants and old fashion wing.

In fact the wing is much more high tech than the planks that have historically
been strapped onto various Cessnas and Pipers
It is tapered and has washout in the tips such that they are not providing lift
(and thus drag) at cruising speeds. You thus find that their cruising speed is
higher for the same horsepower engines than most convential (for that read spam
can american) aircraft.
They are also very robust and we have decided to refurbish our 3 x DR400 tugs
rather than buy new ones as they do the job so well.
The only downside to wood and fabric is that they do not take kindly to being
kept outside in inclement weather.
Now if only we could fit a water cooled deisel and airbrakes we would have the
ideal tug
Nigel