Trailer weight distribution demonstration

On Friday, October 14, 2016 at 7:24:24 AM UTC-7, Jonathan St. Cloud wrote:
Not adding anything to the conversation, but I had purchased a Nimbus 4 that had a Pfister (spelling?) tube trailer. The tongue weight was so heavy it could only be moved by a jack. Soon after getting the bird I purchased a double axle Cobra trailer for the glider and sold the other trailer. The new cobra had a tongue weight much less than the former trailer and could be moved by hand and towed marvelously. Of course back then I was towing with a 2500 chevy Suburban and I had to put a post it on the dash to remind me that I was towing a trailer. While not an expert in any field of this particular discussion, it seems tow vehicle has much to do with the stability as the trailer. My ASw-24 towed towed great behind my little four banger Toyota pick up and horrible behind my next car a Jeep Grand Cherokee. The Suburban was my favorite tow vehicle but I had to keep reminding myself of the trailer. I am currently towing an ASG-29E with a ML 350 diesel and it tows great, but I do have a double exile trailer.

The Jeep Grand Cherokee has a bad reputation as a tow vehicle. I personally saw one (attempting to) towing a small travel trailer. It was not stable and I witnessed severe swaying at a relatively slow speed (50 mph). The driver would slow down when it went unstable, and then creep back up to the speed that it would go unstable again. It was disturbing to watch - the driver had his family in the car and they were all at risk. I think the problem was the short wheel base in combination with the suspension and the tires. If they are too soft there isn't sufficient damping to stop swaying. This is further aggravated by the length of glider trailers. Yet they are rated to tow pretty hefty trailers. The moral of the story is just because the drive train can handle the trailer weight doesn't mean that it will be stable at highway speeds.

Tom

On Saturday, October 15, 2016 at 11:05:40 PM UTC-7, 2G wrote:
On Friday, October 14, 2016 at 7:24:24 AM UTC-7, Jonathan St. Cloud wrote:
Not adding anything to the conversation, but I had purchased a Nimbus 4 that had a Pfister (spelling?) tube trailer. The tongue weight was so heavy it could only be moved by a jack. Soon after getting the bird I purchased a double axle Cobra trailer for the glider and sold the other trailer. The new cobra had a tongue weight much less than the former trailer and could be moved by hand and towed marvelously. Of course back then I was towing with a 2500 chevy Suburban and I had to put a post it on the dash to remind me that I was towing a trailer. While not an expert in any field of this particular discussion, it seems tow vehicle has much to do with the stability as the trailer. My ASw-24 towed towed great behind my little four banger Toyota pick up and horrible behind my next car a Jeep Grand Cherokee. The Suburban was my favorite tow vehicle but I had to keep reminding myself of the trailer. I am currently towing an ASG-29E with a ML 350 diesel and it tows great, but I do have a double exile trailer.

The Jeep Grand Cherokee has a bad reputation as a tow vehicle. I personally saw one (attempting to) towing a small travel trailer. It was not stable and I witnessed severe swaying at a relatively slow speed (50 mph). The driver would slow down when it went unstable, and then creep back up to the speed that it would go unstable again. It was disturbing to watch - the driver had his family in the car and they were all at risk. I think the problem was the short wheel base in combination with the suspension and the tires. If they are too soft there isn't sufficient damping to stop swaying. This is further aggravated by the length of glider trailers. Yet they are rated to tow pretty hefty trailers. The moral of the story is just because the drive train can handle the trailer weight doesn't mean that it will be stable at highway speeds.

Tom

The older Jeep Cherokee was the same, especially when low on fuel. Install better shocks and it's fine.
Jim

Higher mileage Jeeps are also know for the "Jeep death shake/weave" on their own, even without a trailer. Not a good choice unless worn suspension bits are replaced.
Yes, we owned a 1998 Cherokee Sport for a couple years, lots of bottom bits were replaced.
High CG, tall tires, worn bits, shortish wheel base for its height.

A good tow vehicle should be sorta heavy, long, low (think 60's & 70's US station wagons). Yes, other vehicles can tow (I crewed, about 1979, driving a VW Beetle towing a plywood ASW-15 trailer, it had a hard time doing 55MPH on flat ground.....empty!), but some vehicles have an easier time with ANY trailer.

Is there much point in comparing worn out cars? In my case the boxy '87 Cherokee was bought new, and its first road trip was a 4-day drive to pick up an LS4.
Took a lot of messing around with the trailer and car to find the real fix.
Jim

On Wednesday, October 5, 2016 at 5:20:36 PM UTC-4, wrote:
On Wednesday, October 5, 2016 at 4:50:51 PM UTC-4, wrote:
In the early 1970s, my father and I loaded our damaged 201 Libelle into a tall, straight-topped, corrugated-aluminum-and-steel-tube trailer meant for a 16.5M Diamant. Almost unbelievably given the weight of the Diamant wing, it was set up to load wingtips first from the rear. So that's how we loaded the Libelle wings: i.e., spars aft. The fuselage we just rolled into the trailer and tied it down as best we could using the tail tiedown bracket that was in place.

As you can imagine with our short-span bird sitting well aft of where the Diamant would be, the trailer was somewhat tail heavy. Off we went in the family Chevy station wagon (read: heavy, full-size American car from that era) from Cincinnati to the Gehrleins' repair facility in Erie, PA, a 350 mile journey that should have taken about 5 hours.

I have long since suppressed most memories of that terrifying trip but not the lessons of that masters-level, crash course (no pun intended, fortunately) in trailer control. Everything I know about keeping uncooperative trailers in line I learned that day. I almost had to pry my fingers off the steering wheel when we arrived.

I learned how to slow going uphill so I could avoid slowing (not good) or braking (really bad!), and even accelerate slightly if needed on the way down the hill. How to accelerate slightly when being passed by a large truck. Or anything larger than a motorcycle, for that matter. How to watch in the mirror to make certain there were no large trucks overtaking as we reached the top of a hill.

How never to touch the brakes going around a curve. How to hit the throttle to straighten out an incipient tail wag, including when going downhill being passed by a large truck (see "how to slow going uphill", above).

I don't know why we didn't just stop and move things forward, or pile a bunch of stuff in the front of the trailer to get some tongue load. I guess we didn't know any better. Or assumed it was some fundamental flaw in trailer stability. The empty trailer towed fine on the way home, unsurprisingly. If I recall correctly, the subsequent owner of that glider moved the axle back to get some more weight on the tongue even with the heavier, longer-span Diamant in the box, and it towed fine.

To this day, almost 45 years later, I'm still wary of the little twitch in the steering wheel that signals the trailer is moving around and could get squirrelly.

Chip Bearden

My PIK trailer was a bit wiggly when pulling with my little Triumph TR7. It did get rolled when we got run off the road by a truck and ended up with an uncontrollable divergent oscillation.
The glider did not get hurt and flew in my first Nationals 2 days later(another story).
When repairing the trailer I replaced the front frame members with one size larger tubing and extended the tongue area about 8 inches. It was like a different trailer and never wiggled again. Tongue weight was almost exactly the same so my theory was that the longer arm from the tow ball to the oscillation dampers(wheels) was enough to entirely change the dynamics.
FWIW
UH

Just Catching up now... As the previous owner (first car) of a Triumph Spitfire and the current owner of a Pik, i really hope you have a photo of that setup, and if so, would love to see it!
G7

On Sunday, October 16, 2016 at 9:33:32 AM UTC-5, Charlie M. (UH & 002 owner/pilot) wrote:
Higher mileage Jeeps are also know for the "Jeep death shake/weave" on their own, even without a trailer. Not a good choice unless worn suspension bits are replaced.
Yes, we owned a 1998 Cherokee Sport for a couple years, lots of bottom bits were replaced.
High CG, tall tires, worn bits, shortish wheel base for its height.

You can tow with a Jeep Cherokee, but you have to have everything setup correctly: upmarket tires at max PSI, air shocks on rear axle, proper tongue weight, trailer tires at correct pressure and type. With that, my old 1997 Cherokee Sport with 230K miles tows fine up to 70 mph (15m Cobra with trailer tires). But it took a while to sort it out! (and the brakes are marginal going down long hills...)

But a longbed pickup - or an RV? Can't even tell there is a trailer behind....

Now when you have to pull that trailer out of the middle of a huge disced field in the middle of nowhere at 2 AM - that 4WD Cherokee is nice to have around, warts and all. Which is why it's still in my garage.

Horses for courses, is the saying I believe.

Kirk
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