Which Tow Vehicle

Which vehicle to tow a glider trailer has been debated
ad nauseum on RAS. I have always been a staunch supporter
of towing with a full-size truck. After the events
of last Thursday, I feel my position is vindicated.

I was towing my sailplane westbound on Interstate 40
near Gallup, NM. I had just come through a nasty rain
& hail storm bad enough that traffic had been stopped
completely for several minutes. The worst part of
the storm passed quickly, but there was still moderate
rain as traffic began moving again. I was up to about
40 MPH when an eastbound GMC Yukon lost control and
spun into my westbound lane. I managed to get nearly
stopped before he spun head-on into me. Despite major
damage to both vehicles, all 7 occupants (me + 6 in
the Yukon) walked away completely unhurt! My sailplane
and trailer suffered absolutely no damage.

My wife arrived about 2 hours later with the backup
truck and I was able to continue to the airshow in
Kingman, AZ. A very thorough inspection of the sailplane
before assembly showed no indication at all of the
crash. The items in the seat pan were undisturbed,
the G-meter still showed the levels from my last aerobatic
flight and there wer no indications of any bumping
or scuffing anywhere on the wings or fuselage.

It was an emergency stop, downhill on very wet pavement.
About the worst possible scenario for a controlled
stop with a trailer. I hate to think what would have
happened if I'd been towing with a VW or Z3.

Here's the link to a photo of the crash (Mine is the
white Dodge, the trailer isn't visible in the photo).

http://www.silentwingsairshows.com/images/wreck.jpg

Despite the fact that he was driving a $40,000 Yukon,
the other driver had no insurance (or job, or phone
number, ...), so my uninsured motorist coverage will
cover the damages, while Mr. Ortega and family walk
away with nothing but a pair of citations for driving
too fast for conditions, and no insurance. I'm already
looking for another truck.

Bob C.

On Oct 9, 1:43 am, Bob C
wrote:
Which vehicle to tow a glider trailer has been debated
ad nauseum on RAS. I have always been a staunch supporter
of towing with a full-size truck. After the events
of last Thursday, I feel my position is vindicated.

I was towing my sailplane westbound on Interstate 40
near Gallup, NM. I had just come through a nasty rain
& hail storm bad enough that traffic had been stopped
completely for several minutes. The worst part of
the storm passed quickly, but there was still moderate
rain as traffic began moving again. I was up to about
40 MPH when an eastbound GMC Yukon lost control and
spun into my westbound lane. I managed to get nearly
stopped before he spun head-on into me. Despite major
damage to both vehicles, all 7 occupants (me + 6 in
the Yukon) walked away completely unhurt! My sailplane
and trailer suffered absolutely no damage.

My wife arrived about 2 hours later with the backup
truck and I was able to continue to the airshow in
Kingman, AZ. A very thorough inspection of the sailplane
before assembly showed no indication at all of the
crash. The items in the seat pan were undisturbed,
the G-meter still showed the levels from my last aerobatic
flight and there wer no indications of any bumping
or scuffing anywhere on the wings or fuselage.

It was an emergency stop, downhill on very wet pavement.
About the worst possible scenario for a controlled
stop with a trailer. I hate to think what would have
happened if I'd been towing with a VW or Z3.

Here's the link to a photo of the crash (Mine is the
white Dodge, the trailer isn't visible in the photo).

http://www.silentwingsairshows.com/images/wreck.jpg

Despite the fact that he was driving a $40,000 Yukon,
the other driver had no insurance (or job, or phone
number, ...), so my uninsured motorist coverage will
cover the damages, while Mr. Ortega and family walk
away with nothing but a pair of citations for driving
too fast for conditions, and no insurance. I'm already
looking for another truck.

Bob C.

Bob glad to see that you are OK. does your trailer have brakes as
well? glad to hear that your glider is OK, that is a recurring
nightmare for me. one moron on the road is all it will take to
destroy my baby.

Probably exactly the same thing.

On Oct 9, 1:43 am, Bob C
wrote:
It was an emergency stop, downhill on very wet pavement.
About the worst possible scenario for a controlled
stop with a trailer. I hate to think what would have
happened if I'd been towing with a VW or Z3.

C'mon Bert, Newton says otherwise...Remember F=MA?
I'd bet lots that a VW or Z3 hit by a Yukon wouldn't
have fared so well. Also without the mass ahead of
it, the trailer would have seen a lot more of the energy.
Whatever...

BTW, no, the trailer did not have brakes. The surge
brake has been disabled. Because it's sure to bring
on a severe flaming, I won't go into the dynamics of
a fishtailing trailer and surge brakes, but in many
circumstances, surge brakes can actually make things
worse. PM me if you want to hear this one...

Bob C.


At 14:36 09 October 2007, Bert Willing wrote:
Probably exactly the same thing.

On Oct 9, 1:43 am, Bob C
wrote:
It was an emergency stop, downhill on very wet pavement.
About the worst possible scenario for a controlled
stop with a trailer. I hate to think what would have
happened if I'd been towing with a VW or Z3.

On 9 Oct 2007 14:50:54 GMT, Bob C
wrote:


BTW, no, the trailer did not have brakes. The surge
brake has been disabled. Because it's sure to bring
on a severe flaming, I won't go into the dynamics of
a fishtailing trailer and surge brakes, but in many
circumstances, surge brakes can actually make things
worse. PM me if you want to hear this one...

Sounds interesting, Bob. How about sharing your experiences with the
group?
I certainly would never tow a trailer without a brake, but I'm always
interested in heraing other point of views.



Bye
Andreas

In Len Deighton's astonishing 1970 novel "Bomber" there is a passage
(which I believe to be true, Deighton researched his novel to an
incredible degree) describing a pilot diving his Lancaster in the hope
that the increased airflow would extinguish the fire in one his
engines. He had been told of this technique by pilots who had
successfully done the same thing. However, the usual outcome was in
fact that the fire became hotter and eventually burned through the
main spar, leading to the seperation of the wing.

Those pilots did not get to report their experiences to their
colleagues.


Dan

Bob C wrote:
C'mon Bert, Newton says otherwise...Remember F=MA?

F=MA isn't so important if the M isn't used efficiently, which is true
of some trucks and SUVs. Sometimes bigger isn't better, it's just
bigger, and if the "M" makes for a high center of gravity, it can be
worse. Crash protection comes from putting the "M" in the right shape
and the right place, along with a good implementation of seat belts and
airbags.

I'd bet lots that a VW or Z3 hit by a Yukon wouldn't
have fared so well. Also without the mass ahead of
it, the trailer would have seen a lot more of the energy.

Sure, but if it's a good trailer, the glider would still be undamaged.

BTW, no, the trailer did not have brakes. The surge
brake has been disabled. Because it's sure to bring
on a severe flaming, I won't go into the dynamics of
a fishtailing trailer and surge brakes, but in many
circumstances, surge brakes can actually make things
worse.

How long is your trailer, how much does it weigh, and why do you think
it might start fishtailing?

--
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

Bob:

As a physicist, I am also a great believer in Newton's laws.

I once towed a trailer containing my Jantar-1 (19 meters) with a VW
bug, or rather I should say the trailer propelled my bug down the road
only marginally under control. I terminated that experiment very
quickly!

Since that attempt, I have used larger vehicles (station wagons in the
old days) or SUVs more recently.

I now use the moderately-sized Toyota 4Runner (Prado Land Cruiser to
the rest of the world), which has a V8 gasoline engine as an option
here in the USA. It's the perfect size, weight and power for towing a
single-place sailplane ( I tow a Discus 2). The standard gasoline
engine here or the diesel available in much of the rest of the world
would be OK at sea level, but in my view you need both sufficient mass
and power in the tow vehicle to maintain control and stability.

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!

Mike

Bob,
You have to remember that your vehicle was badly damaged BECAUSE it
weighs so much. The frame of your vehicle had to absorb your weight. A
lighter vehicle would not have to absorb as much energy to come to s
stop, as it weighs less.

It doesn't matter if the vehicle hits an immovable object or if you
get hit by a moving object from the front. The calculation is the same
for your vehicle to come to s stop or decelerate. The mass your
vehicle plays a very important role and the heavier it is the more
energy needs to be absorbed and the more damage there will be.

So to compare the damage to your truck and say that this would happen
to a lighter vehicle is just plain wrong. A lighter vehicle would
sustain less damage is constructed the same as the truck.

The fact of the matter is though, that lighter newer vehicles can
absorb more energy per pound than heavier vehicles and thus would
sustain far less damage than a heavier vehicle.

I've seen a crash test of a smaller Renault against a Land Rover and
the Land Rover was in worse shape after the head on collision test -
especially the occupants.

So safety design and weight are the biggest factors in survivability.
All things being equal, it's safer to be in a lighter vehicle in a
crash as there is less energy for the frame to absorb.

The Ford F-150 is one example. And can your truck's roof even hold the
weight of the truck should it over turn? Light vehicles don't have
this problem and have a lower CG as well.

Your breaking power is also less than a lighter vehicle's - contrary
to what many may think, again because of the heavier weights. Stopping
distances are less in a lighter vehicle - always.

If the lighter tow vehicle has good breaks, like most modern smaller
cars do and good tires, that are not that much smaller than your truck
tires, say 15-17 inches , then a lighter car will stop much shorter
than your truck.

"Mike the Strike" wrote in message
oups.com...
Bob:

As a physicist, I am also a great believer in Newton's laws.

I once towed a trailer containing my Jantar-1 (19 meters) with a VW
bug, or rather I should say the trailer propelled my bug down the road
only marginally under control. I terminated that experiment very
quickly!

Since that attempt, I have used larger vehicles (station wagons in the
old days) or SUVs more recently.

I now use the moderately-sized Toyota 4Runner (Prado Land Cruiser to
the rest of the world), which has a V8 gasoline engine as an option
here in the USA. It's the perfect size, weight and power for towing a
single-place sailplane ( I tow a Discus 2). The standard gasoline
engine here or the diesel available in much of the rest of the world
would be OK at sea level, but in my view you need both sufficient mass
and power in the tow vehicle to maintain control and stability.

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!

Mike

My experience exactly. I started towing glider trailers with a 85hp Volvo
544 with drum brakes - really bad idea since the car self-destructed under
the stress of towing a trailer. My next car was a '66 Shelby 350 Mustang
with disk brakes. The 'stang worked OK but it was still way too light. It
made for FAST retrieves though.

In the early days a V8 Chevy BelAire station wagon was the ticket but
limited cooling capacity meant that on long uphill grades in the desert it
required shutting off the air conditioner, turning on the heater and
everybody leaning as far out the windows as possible to avoid being cooked.
On the downhill grades, you used the air conditioner as added compression to
save the brakes.

The long term experience in the western USA is that anything with a V8, disk
brakes and a BIG radiator works but anything less leads a short, ugly life.
Modern SUV's are politically incorrect but they sure work a lot better than
what we used to have.

Bill Daniels