Which Tow Vehicle

"Tom Gardner" wrote in message
ups.com...



That's not correct either. The human body can survive an instant peak
G of about 150 (the known record is 180, David Purely in a F1 car in
1977, who did 108-0 mph in 26").

It is always possible to find an exceptional case to prove or disprove
any contention.



All this talk about big vs. little (g). Here's a short clip that pretty much
proves something or another . . .

bumper

http://www.youtube.com/watch?v=lAfZ1N56qjY

Just for interest:

http://www.youtube.com/watch?v=86M_fV-1yKY

bumper wrote:

All this talk about big vs. little (g). Here's a short clip that pretty much
proves something or another . . .

http://www.youtube.com/watch?v=lAfZ1N56qjY

And here's what happens when you try to make an evasive maneuvre with a
SUV...

http://www.youtube.com/watch?v=dIEnQFpMj2Q&NR=1

Another interesting series of tests with SUVs. In my opinion, large
doors and large "soft" spots in large SUV's do not make them safer.
Look at the pictures and the results, especially in side impact.

http://www.msnbc.msn.com/id/21228894/

The fact that SUVs are also heavier and thus, due to their higher
inertia and mass, will incur even more damage than a smaller car -
which will bounce somewhat and in any case have to absorb less energy
from its own mass, speaks against the safety of the larger vehicles in
a side impact. If the SUV flips as well, it's all over for the
occupants in most SUVs, thoufg not in cars.

My main point here, is that SUVs are not safer nor better as tow
vehicles. They may feel safer, but are they really? The tests show
that it is not always the case.

At 17:54 11 October 2007, John Smith wrote:
bumper wrote:

All this talk about big vs. little (g). Here's a short
clip that pretty much
proves something or another . . .

http://www.youtube.com/watch?v=lAfZ1N56qjY

And here's what happens when you try to make an evasive
maneuvre with a
SUV...

http://www.youtube.com/watch?v=dIEnQFpMj2Q&NR=1

Short wheel base, high center of gravity. Wonder how
this vehicle compares to the Renault in that respect.

It is said that one of the Naderite early advocates of air bag technology
remarked that, "Given the fact that the death rate did not drop nearly as
much as we had expected because drivers adjusted their driving style to be
more aggressive in the belief that they were totally protected by air bags,
it might have been more effective to have mounted a bayonet on the steering
column aimed at their hearts." "That way, knowing that instant death would
follow any collision, they would have been more careful."
Bill Daniels



"Nyal Williams" wrote in message
...
At 17:54 11 October 2007, John Smith wrote:
bumper wrote:

All this talk about big vs. little (g). Here's a short
clip that pretty much
proves something or another . . .

http://www.youtube.com/watch?v=lAfZ1N56qjY

And here's what happens when you try to make an evasive
maneuvre with a
SUV...

http://www.youtube.com/watch?v=dIEnQFpMj2Q&NR=1

Short wheel base, high center of gravity. Wonder how
this vehicle compares to the Renault in that respect.

Dan G wrote:


*Have 7% of the trailer's actual mass on the hitch. Measure with some
bathroom scales and a length of wood cut to the correct height to fit
between hitch and the scales. It's important to get this number right
- no more, no less. If the 7% value is more than the car's noseweight
limit, you'll just have to keep within that limit and accept a less
than optimum noseweight.

We've discussed this one before, and there is no evidence suggesting 7%
is appropriate for glider trailers, as the number comes from a study of
caravans (travel trailers). The more common numbers are 10%-15%, also
with the requirement to stay within the vehicle and hitch load
specifications.

The list does not include the most important factor: speed. Every tow
vehicle and trailer is stable below some speed; unfortunately, there
isn't any safe and easy way to determine this that I know of. I do
suspect most trailer accidents from loss of control could be avoided if
the driver had paid attention to signs of instability in the past, and
drove more slowly as a result.

--
Eric Greenwell - Washington State, USA
* Change "netto" to "net" to email me directly
* "Transponders in Sailplanes" http://tinyurl.com/y739x4
* "A Guide to Self-launching Sailplane Operation" at www.motorglider.org

Paul Hanson wrote:
(maybe all - I don't know of an exception) flight manuals
tell you to
never land gear down.

Uhh, gear up you mean? : )

Oops!

There are exceptions however,
like in a water landing for instance. You don't want
the gear down as it causes the glider to violently
pitch down and submarine on touch...err-splashdown,
greatly increasing the risk of smashing into the lake/river/ocean
bottom and/or drowning.

The opposite is actually true; for example, my 12 year old ASH 26 E
manual specifically states a water landing requires the gear down for
maximum safety. Tests show the typical glider fuselage will submarine
with the gear up; with the gear down, it does not submerge as much, and
the gear protects the pilot from any impact with the bottom.

It is possible that flight manuals from older gliders (older than 20
years, say) might suggest landing in water with the gear up - I can't
recall when the water landing research was done.

Uncle Hank where are you?
Another exception is my Sisu 1a. It has a shock absorbing
oak skid with a steel shoe, in addition to a retractable
main. If the field looks to cloddy or the grass too
tall it is recommended not to lower the gear. AJ Smith
gave it it's first wheel up (unintentional however)
and Johnson the second, both without damage to them
or the ship. But landing gear up is generally a bad
habit, for many reasons, including having a crumple
zone.


--
Eric Greenwell - Washington State, USA
* Change "netto" to "net" to email me directly
* "Transponders in Sailplanes" http://tinyurl.com/y739x4
* "A Guide to Self-launching Sailplane Operation" at www.motorglider.org

Hmmm... where to begin in response to this, Dan. First you claim that a
previous poster was using a "strawman" argument and then you immediately
begin to use the Reductive Fallacy (oversimplification) argument.



It would be nice if we could apply a few simple rules to any problem and
have it solved. However, a vehicle towing a trailer is a _very_ complex
system requiring much more than a few "shoulds" or "Do these x things
and everything will be fine" approaches. In addition to the obvious
things that have been written about in this thread (vehicle weights,
tongue weights, tires and tire pressures, etc.) there are _many_ other
significant factors in play. To name a few (very incomplete list):



--moment arm of the hitch ball to rear axle of the car (one of the most
significant from my experience)

--suspension dynamics of tow vehicle

--aerodynamic shape of the trailer

--combined aerodynamic interactions between tow vehicle and trailer

--environmental considerations where you tow ( prevailing wind, etc.)

--proximity to field effects of passing vehicles, etc.

--necessary or desired speed for trip

-- on and on.......



So to say that "Towing is simple. Follow these rules, and your rig will
be stable in all conditions and not need stabiliser hitch." is in my
experience a gross oversimplification.



Larry

"zero one"

USA















"Dan G" wrote in message
ups.com:

On Oct 9, 10:30 pm, Mike the Strike wrote:
Yes, I know we'll get posts from the guys who'll tell us they towed
their Duo Discus over the alps using a Fiat 500. That doesn't meant
that it is necessarily a good idea!

Nobody has ever suggested that - I believe that is a "strawman"
argument.

Towing is simple. Follow these rules, and your rig will be stable in
all conditions and not need stabiliser hitch.

*Make sure that the laden mass of the trailer does not exceed 85% of
the laden mass of the tow car, and preferably less.

*Have 7% of the trailer's actual mass on the hitch. Measure with some
bathroom scales and a length of wood cut to the correct height to fit
between hitch and the scales. It's important to get this number right
- no more, no less. If the 7% value is more than the car's noseweight
limit, you'll just have to keep within that limit and accept a less
than optimum noseweight.

*Carry heavy items in the car, not the trailer, but make sure you
don't exceed the maximum axle load (or end up with your car dragging
its arse along the road). I often put the heaviest
items in the passenger footwell if I'm travelling alone.

*Look after your tyres on both car and trailer. Blow-outs can really
ruin your trip (and your glider!). Trailer tyres should be replaced
every five years and definitely every seven - rubber ages naturally,
whether you use them or not. In winter ideally take the wheels off
and
store them level in a cool dry place wrapped in hessian (not
plastic),
or at least wrap the tyres in hessian on the trailer to keep the UV
off.

*Make sure you run the correct tyre pressures all round. Check before
you set off on every trip. A tyre with low pressure will run hot and
could blow.

Now, I didn't want to mention this earlier as it sounds like willy-
waving, but I once performed a maximum-effort stop from 70 mph in a
light Euro car with an Astir on the back in pretty old trailer (no
Cobra). The car and trailer were well maintained and pulled-up very
quickly in a perfectly straight line. I could have probably let go of
the wheel.


Dan

Martin Gregorie wrote in news:kg50u4-
:

I'd never knock the series II or III. Mine did a London-India out and
return in 10 months without any problems apart from a tendency to
consume speedometers that I never got to the bottom of, a clutch change
in Mysore and a clutch slave cylinder replacement in Turkey.

I had a series II with a 4litre perkins diesel engine.
Yes, it would pull the skin off custard, and yes the
engine mountings and transmission spiders were problematical.
Never had any problem with the speedo, but the fuel guage
was calibrated in Roentgens per hour (that being the best
one I could lay my hands on at the time

It was a simple machine and easy to maintain with relatively few tools:
almost everything could be removed and reinstalled with only 3 or 4
different ring spanners and a screwdriver.

Mine seemed to have a lot of parts in common with Minis,
e.g. rear lights and driver's seat.