im hoping one of you guys is some sort of physacist and knows the answer to my predicament. i wanted to know if when cornering with a trailer, concidering that centrifugal forces are acting, does the weight of the trailer get any heavier? might be a very stupid question but i need to make sure- i am making a small caravan (the teardrop if anyone saw the other posts) and i am in the process of designing the suspension.

if the whole caravan weighs 100kg's, then not concidering the weight in the wheels, the axles-hub joint would only ever experience half that weight- going in a straight line. on a corner, i guess that the 50kg's from the other wheel is shifted onto it, so it experiences twice that weight (100kg's). my question was it that all the weight that it would experience, or would centrifugal forces add any weight, and stress the axle-hub joint any more?

there is nothing to do with aerodynamics and down force here, which will act when its going straight, but the corner question is enough to fry my brains at the moment.

i hope this is makingsense, re-reading what i have written it seems maybe im being very stupid, id just like to know how and why.

i have included the most basic of drawings, frankly im embarresed at the quality of it, but my tablet's broken at the moment, so i cant do any better!!

any help/constructive critisism would be very appreciated!
Rescued attachment centrifugal.JPG

I tend to exagerate things to picture things in my head. If you were to corner too fast, then the trailer would tip over. Just before the trailer tipped up, all of the weight would have been transferred to the outside wheel. Therefore, the trailer would not gain weight but the outside wheel/hub woul be taking more weight.
I'm ignoring the weight on the drawbar!

[Edited on 11/7/06 by owelly]

Could centrifugal force apply downforce? Can't see it myself, as centrifugal force is acting purely sideways. The fact that it rarely acts through a vehicles roll centre and therefore causes it to roll on its suspension can only redistribute the vehicles weight over it's axles - it can't add to that weight.

A single wheel of your trailer is very unlikely to even see the full 100kg unless you intend to corner fast enough to flip it over! And that's assuming there's even enough grip/high enough cog for that to happen - it might just slide.

Liam

Caravan?

The curse of motoring!

Where's the fun in peeing in a bucket?

If you brake in a corner with an unbraked trailer it will try to go straight on and cause the back end of the car to lift which wil be the opposite of the trailer gaining weight but have the same effect. Jroberts, you've watched too much Clarkson, peeing in a bucket is loads of fun, just listening to the change in tone as the bucket fills up gives a real sense of achievement Liam, if you can make this caravan with a weight limit of 100kgs you will be very lucky and if it doesn't push your car when you brake or corner you will be even luckier.

BTW, that drawing is of the highest standard. It looks like one of mine!!

Stop thinking in terms of weight and think in terms of forces.

For example take a trailler or carvan weighing 1 ton.

As already pointed at max cornering speed you get 100% weight transfer to the outside wheel, we will guess max cornering is at 1G.

In 1g cornering for a trailler weighing 1 ton a reaction force of 10kn is generated in the horizontal direction.

Using vector addition add this to the vertical load (also 10kn) and you get a reaction force of 14 kn acting upwards at 45 degrees from the tyres point of contact.

[Edited on 12/7/06 by britishtrident]

Hi,

Worth over engineering anything in this area. Take a look at the link, this happened on the M62 near me on Monday. Very unlucky.BBC

quote:

---

Originally posted by britishtrident
Stop thinking in terms of weight and think in terms of forces.

For example take a trailler or carvan weighing 1 ton.

As already pointed at max cornering speed you get 100% weight transfer to the outside wheel, we will guess max cornering is at 1G.

In 1g cornering for a trailler weighing 1 ton a reaction force of 10kn is generated in the horizontal direction.

Using vector addition add this to the vertical load (also 10kn) and you get a reaction force of 14 kn acting upwards at 45 degrees from the tyres point of contact.

[Edited on 12/7/06 by britishtrident]

---

okay ill put a little more explination on, the weight that im aiming for is 100kg's- the pic is of a similar design- mine will be simplified with carbon fibre for the main body. i cant use indespension units as they aer only really rated at 350kg upwards, and still then they bounce, so on mine the caravan would be all over the place. the caravan will be towed by my locost, which will mean it will be easier for the back end to lift in a corner, as the car is so light.

that runaway wheel thing has certainly scared me, i was starting this post in order to see the minimum the axle will hold, i was always going to over- engineer it anyway.
the suspension i have designed is a mini-moto supension unit, with a sheath over the bottom and top, that than slide over each other with little friction. they are attached- one to the top of the suspension unit, one to the bottom. the hub is attached to one of these, and the chassis is attached to the other. i have simplified this a lot, but it was the strength of the attachments to the hub and chassis that i needed to find what weights/forces would be acting on them, to see how much i would need to strengthen them.

thanks for the help guys, and keep it coming!

pic didnt work
Rescued attachment littleguy.jpg

quote:

---

Originally posted by peterriley2
I wanted to know if when cornering with a trailer, considering that centrifugal forces are acting, does the weight of the trailer get any heavier?

---

quote:

---

What exactly are you asking?

---

To digress a little;

quote:

---

Originally posted by jroberts
Caravan?

The curse of motoring!

Where's the fun in peeing in a bucket?

---

hehe...

12 posts before the centrifugal v's centripetal forces came up...

Just make sure that each side is capable of carrying 150/200+ kgs and you'll be fine. That way even if it were on the point of rolling ie one side taking 100kg, the suspension won't collapse. But remember at this point the forces won't be acting vertically through the suspension unit as it will be turned slightly due to roll.

quote:

---

Originally posted by ReMan

quote:

---

Originally posted by britishtrident
Stop thinking in terms of weight and think in terms of forces.

For example take a trailler or carvan weighing 1 ton.

As already pointed at max cornering speed you get 100% weight transfer to the outside wheel, we will guess max cornering is at 1G.

In 1g cornering for a trailler weighing 1 ton a reaction force of 10kn is generated in the horizontal direction.

Using vector addition add this to the vertical load (also 10kn) and you get a reaction force of 14 kn acting upwards at 45 degrees from the tyres point of contact.

[Edited on 12/7/06 by britishtrident]

---

So the answer is yes then!

If you think of the extreme case where the vehicle/trailer was going round a banked corner, or better still a wall of death, then the faster it goes the "heavier" it will get.
Though obviously a caravan would have tipped over a long time ago.
Can you not use the bolt on indespension units, presumably they are rated with different loadings?

---

How many seats are inside?

This link might be useful, a little known secret about seats and physics!

http://www.vxronline.co.uk/messageboard/viewtopic.php?t=714

see 1st (none blank) reply by "police_Driver"



[Edited on 13/7/06 by skidude88]

quote:

---

Originally posted by skidude88
How many seats are inside?

This link might be useful, a little known secret about seats and physics!

http://www.vxronline.co.uk/messageboard/viewtopic.php?t=714

see 1st (none blank) reply by "police_Driver"



[Edited on 13/7/06 by skidude88]

---

Well it will lower the CoG by almost a mm* Must start cleaning my car to improve the aero


*Wild Guess for humorous effect before the mathematicians start on at me

lol,

"Often I put the rear seats flat, this reduces weight. (Like why you crawl flat across a frozen pond so as not to break the ice)"

dammit, why was the thread locked:

could do with more classis like:

The rear seat thing, It is rare that I fold them down, but it has to be said that when folded they remove a bit of weight. Vertical seats exert more downward force because the energy is focused on a smaller surface area. When horizontal, the weight is spread and so is less per Centimetre squared.

quote:

---

Originally posted by spunky
hehe...

12 posts before the centrifugal v's centripetal forces came up...

---

Wow that's a top tip on the VXR forum.

I just shaved 2 seconds off my 0-60 time in my tin top. Put the back seats down AND the front seats flat! Adjusted the vanity mirror on the sunvisor so I could see where I was going and sort of lay down, wow that was loads faster!

Must try it again with the wing mirrors folded in!

Mike

quote:

---

Originally posted by Guinness
Wow that's a top tip on the VXR forum.

I just shaved 2 seconds off my 0-60 time in my tin top. Put the back seats down AND the front seats flat! Adjusted the vanity mirror on the sunvisor so I could see where I was going and sort of lay down, wow that was loads faster!

Must try it again with the wing mirrors folded in!

Mike

---