A66 caravan smash

Rubbish

I use a Terracan auto - 161 bhp and 253 lbs/ft

Reply to
Budgie
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Budgie ( snipped-for-privacy@hotpop.com) gurgled happily, sounding much like they were saying :

On what possible planet could a Hyundai Terrahawk be considered "fun"?

Reply to
Adrian

Once you get a lot of energy stored in an oscillating system comprising a car and caraven rolling on rubber tyres over uneven ground and a sprung supension (how often do caravanners change the shocker absorbers in their vans, - if they have any) the instability will inevitably spread from vertical to lateral.

At best this will pre-load the suspension of the towing vehicle (making it stiffer) and take up any slack / wear in the tow hitch arrangement.

Just explain please.

I never proposed that.

It is not obvious to me. Save that adding weight to the towbar might have the 2nd order effects I have outlined above.

Please provide a link to the proof.

For the sake of clarity.

Doesn't cut the mustard.

I thought it wasn't.

To a limited extent and for the simple reasons I provided.

?

Why am I not surprised ?

Oscillation is the problem. Why do I not see "damping", or "negative feedback" mentioned in your solution, only adding mass.

One does ones best. Sadly you appear to be none the wiser. If a little better informed.

;-)

DG

Reply to
Derek ^

Well if it does and I dont see why it would in any major way then the cars damping will begin to help remove it! Thats a good thing. Plus if you loaded the van up a little nose heavy you wouldnt have an occilating van anyway...

It does that as well as increasing stability. My automotive dyno trailer weighed rather more than a caravan and went many countries and roads. No wear problems in many years.

A van at static or slow speed balancing behind the wheels will swing further with each swing. A van balancing exactly on the wheels will be neutral. Meaning that it has no tendency to increase its swing or decrease it. (ignoring aerodynamics for now) A van balancing in front of the wheels naturally dampens down the swing until it goes away every time its induced.

But other things effect this stability. The fact that there is a square van in crosswinds means stability is worse as speed increases. To compensate for this some extra noseweight (move c of g forwards further still) is the simplest way. When the load on the towbar becomes too high then you quite simply need a smaller lighter van or a stronger to vehicle that can take the weight it has to do for stability. Hence the truck with a strong tractor unit, trailer wheels at the rear to keep c of g in front of the rear wheels.

You didnt have to. Its just c of g effect. Theoretical. The correct balance point is one that gives you stability at your chosen top speed while not going overboard on the tow bar/rear suspension. But if it snakes you do need more noseweight! If your car towing system cannot stand that you need a different one, or keep the unstable configuration.

Go shove a few bags of cement in the rear of your van, or move the axle forwards (almost the same thing as far as the forces are concerned) and your van will snake at very low speeds and get progressively worse with each swing.

Then move them under the front seats and try again. You should be able to do 70 or more without problem. I did this when going to south of spain. No caravan but moved two 1100cc bikes to the front. Total straight line stability. Try it before you tell me I am wrong.

"LINKS" are not proof of anything. Ask a caravan or trailer designer. Or anyone with a basic understanding of the dynamics involved. Some people will never "get it" others can see this easily.

Yawn...

It will make any caravan tow straight at motorway speeds and thats what this is about.

Only adding mass from the rear of the van to the front.

  • There will be no occilation to try and damp! Its much the same as the infamous "tank slapper" that motorcycles were famous for in the 60s 70s and 80s. One day after fitting various styles and types of steering dampers for 30 years the realised that you didnt need one if you sorted out the reason for it occilating in the first place! Now even faster bikes do not come with steering dampers any longer.
Reply to
Burgerman
180bhp seems to cope quite well
Reply to
Martin

Conor has an obsession against light trailers with overrun braking systems and erroneously believes that fitting 44 tonne style systems to light trailers would increase their safety.

Actually all that is required to ensure good safety of light overrun braked trailers are:

  1. Proper loading
  2. Non-excessive speed
  3. Good driving style
  4. Regular maintenance (MOTs for trailers are long overdue)

ABS would make bugger all difference. Most of the pancake caravans you see result from a combination of (1) and (2) not being fulfilled. Basically, someone in a big Shogun sticks all the weight at the front of the caravan because they can't be arsed to put the gas tanks over the axle. They then pile down the motorway at 95mph and go boo hoo when the unbalanced lot ends up on the wrong carriageway, scattering their offspring as it rolls.

A carefully loaded caravan driven at 60mph with working brakes and a non-muppet driver will not snake. It just won't.

Christian.

Reply to
Christian McArdle

My caravan came back from its annual service last week - the workshop was full when I dropped it off the previous week, and when I collected it after the service.

Reply to
Leyland_Leopard

Completely meaningless. Two caravans could fill my workshop.

Reply to
Conor

Not completely meaningless, although I take your point. Presumably what he meant was that there are plenty of people who *do* get their caravans properly serviced. The same is true where I go. They need at least 6 weeks warning to book it in (at least in May, when I go). That's a lot of caravans being attended to. What this represents as a proportion of caravans in the area I don't know - too few, I'm sure. But *some* owners are responsible.

Reply to
Richard Brookman

But are they being serviced or are they having things done such as cabinet repairs or repairing leaky windows?

Reply to
Conor

Can't speak for the others, but in my case a full chassis service along with the usual damp checks and functions of the interior kit. This would include removal of wheels, check/replace brake shoes, lubricate and adjust brake linkages.

Reply to
Richard Brookman

For towing you need lots of torque, not BHP.

Reply to
Jerry

Which do you think would be better: 200 lb-ft at 2000rpm or 175 lb-ft at 2500 rpm?

Ian

Reply to
Ian

Its the same thing. Power is simply the rate that the torque is produced.

Reply to
Burgerman

In theory, the latter.

Reply to
Ste

You wanna try pulling a caravan with a Civic Type-R ;-)

Reply to
Sandy Nuts

What you really need is a motor that produces good torque lower in its rev range.

Reply to
Burgerman

Yup. Like a *cringe* diesel.

Reply to
Sandy Nuts

Deseasels are good at that thats why they are used in trucks, trains etc. But they are not very flexible (why some cars have 6 gears and trucks dozens! Personally I hate the things.

Reply to
Burgerman

Yep. "Happy Torque"

DG

Reply to
Derek ^

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