On Jan 13, 6:40*am, T8 wrote:
Back to trailers: *From fuel consumption numbers, I can back out that
my Komet trailer/glider has an effective fuel consumption of 120 miles
to the gallon at 60 - 65 mph on level road, no wind.

That's pretty impressive.

When I was towing a Grob two seater in (admittedly a pretty crappy
trailer) it reduced the range of my 2.5l Subaru on a 56l fill up from
about 620 km to about 350 km. Say, from 32 mpg to about 18 mpg.

http://hoult.org/bruce/Subaru_with_TA.jpg

To put it into the normal units used here, the car alone normally uses
about 9 l/100 km on a long trip, and the combo used about 16 l/100km.
That implies that the trailer used about 7 l/100 km, or 40 mpg.

I'm sure a Komet with a single seat glider would be much better, but
I'm surprised it's three times better.

I note in passing that my Subaru&trailer combo used only very slightly
more fuel than my Dad's 4.1 l Falcon station wagon does by itself.


One more point: for most of us outside the USA, I believe that the
practical lower limit on vehicle size for towing is governed not by
power (you can always change down and go slower when necessary) but by
the stability and controllability of the combo under braking and on
steep downhills. Too-small cars are ones that get shoved badly when
braking on downhill switchbacks, and ones that arrive at the bottom of
a couple of thousand foot descent with the brakes smoking.

Here in Wellington NZ, the benchmark is a run over the Rimutaka Hill
to the Wairarapa for a day's gliding at Jury Hill or Masterton. The
summit is only 1800 ft but it's enough to sort the good tow cars from
the bad ones (or stupid drivers who don't use engine braking).