towing

[<JHertzman@xxxxxxx>]

I, carelessly forgetting that bargain car racing class rules are tilted toward
relative affordability first, (and having made the tentative assumption that
the
Bolkow-Messerschmitt 208 "Junior" was probably a relatively aerobatics-
oriented machine), recklessly wrote "I am not up on the weights of
aerobatic aircraft (or any others) but if Joe Chan's formula vee car weighs
appreciably more than the airplane I would think some lessons on structural
efficiency might be learned by the car-builders."

Richard Welty has now explained to me and to the digest that formula vees are
required to weigh at least 1000 pounds and also have very limited latitude on
component choices.

So, to round out (with appropriate chagrin) that part of the thread I asked
the aerobatic lurker roughly what the Messerschmitt weighed. He replied that
the empty weight was about 750 pounds, without wings, and added that it
wouldn't go through the tollgates with the wings on. So the formula vee is
indeed necessarily considerably heavier than the Messerschmitt, even without
the trailer. I stand corrected.

Jaap Bouma gave a thorough and very interesting statement of the rules
governing trailer-use in the Netherlands, and sound advice to boot. The Dutch
(from my perspective, yours may differ) tend to be unusually rational people,
at least compared to any others I have seen. I first visited the country in a
period when virtually all cars had pot-metal hood ornaments and many had
similar devices on fenders, and all such things were missing from their cars,
replaced by smooth buttons, to reduce the possible injuries to unfortunate
pedestrians. That, and many other thoughtful things about the country, made a
lasting impression on me. 

Bouma ends with advice to be very careful what loads you put on a trailer, and
at what speeds you drive it. Absolutely. My pace with the heavy van was quite
leisurely, encouraged by fuel economy as well as instinctive self-
preservation, if not social responsibility. He mentions the substantial loads
imposed by a towed vehicle in critical worst-case emergency situations, and
says "Try feeding that kind of load through your bumper mounts!" Never have,
never will. I was raised with bumpers which were parking aids, graduated to
bumpers which were essentially decorative, and now have bumpers which are
letter-of-the-law fictions. The tail-skid of the Messerschmitt apparently was
not too much for the Colli Promiscua, but I have (so far) always been able to
figure a way to distribute the hitch load fairly broadly in the rear structure
of the car, bypassing the bumper.

Welty is also concerned with vehicle dynamics, including tongue weight- "too
little, and the trailer will try and wag the tow vehicle. too much, and the
rear of the tow vehicle and the front of the trailer will sit down too much."
I had mentioned compensating hitches, spring bars pivoted on a vertical axis,
so that "the rear of the tow vehicle and the front of the trailer" can sit
where you want them. The heavier-duty compensating hitches have hydraulic
dampers in both vertical and horizontal planes, which give a bit more leeway
in controlling overall vehicle dynamics than a simple tongue-on-the-bumper
hitch will have.

Travel trailers in the United States (like many other things) stretch beyond
the limits which would be considered reasonable in many other places. My local
travel-trailer place tells me that the largest trailer you would want to use
without going to a fifth-wheel rig would be about 36'-38', and about 11,000#
(5000 kg). I haven't checked-out recommended tow vehicles, but I doubt that
many of then would meet Richard's rule-of-thumb recommendation of "a tow
vehicle that weighs at least 1000lbs more than the stuff being towed" with
such a trailer. Some of the logic which applies to making this sort of thing
manageable can be applied to the relatively light duty of pulling a Formula
Vee behind an Alfetta, which is where this thread started. I looked and
listened a bit before heading off for our travels, and survived. The thread
started with a question about the adequacy of certain Alfas as tow cars, and
my basic point is that their engines, drive-lines, brakes, and structures are
generally far more adequate than those of other cars of similar size and
nominal capabilities. I still think so. 

Cheers to all, 

John

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