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Turning Radius of 40 foot Cotton Trailer

  1. Mar 2, 2013 #1
    Can I make a 90 degree turn on my 20 foot wide road pulling a 40 feet long and 10 feet wide cotton trailer? The cotton trailer has two axles in the rear and two axles in the front.

    I am an organic farmer and wish to employ a cotton trailer as a mobile chicken coop for my Rhode Island Red hens.

    After pulling the cotton trailer to my farm with my pickup truck I can use my tractor to both pull the cotton trailer and pick up the cotton trailer's rear to nudge it around the 90 degree turn if necessary.

    Thank you.
  2. jcsd
  3. Mar 2, 2013 #2


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    Is the motion of the trailer restricted to the road?
    If yes, how could something 40 feet long fit in something 20 feet wide after a 90°-turn?
    If not, I don't understand the question.
  4. Mar 2, 2013 #3

    Maybe mine is a dumb question and the obvious answer to it is no but I saw this page.

    That trailer is over 42 feet long but can make a 90 degree turn on a road 27 feet wide.

    I was hoping the narrow width of the cotton trailer would allow me to make the turn. Don't forget I have the ability to lift the rear of the cotton trailer with my front end loader and move it.

    Another way to ask the question would be, how wide must a road be in order to accommodate a 90 degree turn with a 40 foot long and 10 foot wide trailer?
  5. Mar 2, 2013 #4
    What is the radius of the 90 degree turn you wish to make?
  6. Mar 2, 2013 #5
    OK here's what I've come up with.

    I'll assume that the road makes a 90 degree arc around a point I'll call X.
    I'll assume the rear axle must be perpendicular to the trailer and that the front axle pivots.

    When the trailer is turning, the front and rear axles will fall on radi of the circle it is turning on, in our case that circle's center is at X.

    For the purposes of making a clear mental picture I will assume a right turn (the outcome will be the same for either right or left). The part of the trailer closest to X will be the right rear wheel, I shall call the distance from the right rear wheel to X, A. The furthest point on the trailer from X will be the left front corner, I shall call the distance from the LF corner to X, B.

    The width of the road is 20' so for the tightest possible turn...
    Add A to both sides
    The width of the trailer is 10' and the length is 40' so in order to get from the RR wheel to the LF corner I have to go outward 10' and forward 40'.

    Now I construct a right triangle with one leg being A+10', the second leg being 40', and the hypotinuse being B.
    Substitute A+20 for B
    multiply out the squares
    Subtract A2+20A+400 from both sides
    Devide both sides by 20

    So if the distance from the center of the turn to the inside edge of the road is 65' or more then the trailer can make the turn.
    Last edited: Mar 2, 2013
  7. Mar 2, 2013 #6
    I uploaded an image which depicts the road, Pear Lane. I would be traveling from Monterey Road onto Pear Lane. The 90 degree turn in question is a right hand turn. Pear Lane is 20 feet wide from Monterey Road South. Pear Lane is 21 feet wide East to West.

    It seems obvious the only possible way to make the turn is to lift the rear of the trailer with my front end loader which I can do.

    I misstated the matter by injecting 'turning radius.' Could a 40 foot long and 10 foot wide log make the turn if required to stay within the confines of the road tunnel?

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  8. Mar 2, 2013 #7


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    There are some relevant facts missing, so far.
    Can you overhang the road? Are there fences defining the width of the road or is there a verge, for instance?
    Where are the wheels ?
    What is the radius of curvature of the inside kerb? This would be relevant to where the back wheels can go.

    Why not draw a scale plan of the situation and make a paper cutout of the vehicle?
  9. Mar 2, 2013 #8

    Fences define the width of the road. And one correction: the width of Pear Lane going East to West is more accurately stated as being 22 feet.

    4 wheels are located in the front and 4 wheels are located in the rear of the trailer.

    What is the radius of curvature of the inside [curb]?

    It is an upside down L. Pear Lane going South is 20 feet wide. Pear Lane going East to West is 22 feet wide. The lines are all straight as an arrow.

    This idea has occurred to me. What scale would you recommend given the 40 foot long and 10 foot wide trailer and 20 foot wide road?

    Thank you.
  10. Mar 3, 2013 #9


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    I really don't think you are taking this problem seriously - or perhaps you just don't appreciate that some of those details could be crucial. You would be really screwed if you launched into this and got stuck on the bend, wouldn't you?
    I asked where the wheels are because the detailed position could be important - of course they are near the front and near the back but where and how much does the back end hang over? The front axle will be pivoted, presumably?? Again, where? That is all relevant stuff in a tight situation. Stand near a tight corner in the road and watch how big trucks negociate it. Some drivers seem to do very unlikely things in order to get round with very long trailers.

    I asked the radius of curvature on the inside of the bend because that could also be relevant - there is no such thing as an "L". Pretty well all kerbs have some radius.

    The scale model is really the only way. Any scale would do but the bigger the better. And remember, there are wheels and not castors on this trailer so the path taken by the back wheels needs to follow the line that wheels would take - no slipping sideways like you would when moving furniture round a bend in a corridor :wink:

    Actually, I'd be inclined to find an experienced goods driver (does anyone deliver goods that way?[edit: i.e. along that road]) and actually ask their opinion about this particular problem. They do develop a very good feel for these things. If in any doubt - don't even try it. Embarrassment can be a painful emotion and it could even cost you money.

    Is there not an alternative route you could take? Longer could be better??
    Last edited: Mar 3, 2013
  11. Mar 3, 2013 #10
    So you're saying the radius of the inside curb is 0. 0<65' Therefore you cannot make the turn.
  12. Mar 3, 2013 #11
    I appreciate that I am as dumb as a fence post. :smile: I understand the details are crucial but I have not been sure what details were required to analyze the simulation. The trailer in question is $2500 and I will not buy it until I am absolutely certain I can make the turn.

    The trailer in question is not owned by me yet and it's located about 2 hours from where I live but I will ask the seller if not the manufacturer KBH to provide detailed information about the location of the wheels/axles. And I googled turning radius before joining this forum. Simple trigonometry? :confused: I was hoping y'all could do the high math and provide me with a simple answer. :wink:

    I am not sure how to provide you with the radius of curvature. I look at this definition and glean (The distance from the center of a circle or sphere to its surface is its radius. For other curved lines or surfaces, the radius of curvature at a given point is the radius of a circle that mathematically best fits the curve at that point.)

    I have attached a diagram that might aid in me understanding what you need.

    Actually, given I can lift the trailer with my tractor's front end loader, the trailer would be making the turn somewhat akin to moving furniture round a bend in a corridor.

    I'll ask my very good UPS driver his opinion and others. Good suggestion. And I will not be buying the trailer until 100 percent certain I can make the turn.

    No. One way in and one way out.

    Thank you.

    Attached Files:

  13. Mar 3, 2013 #12


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    If all numbers would be exact, it does not fit. Consider a symmetric setup where both roads are 21' wide: The critical moment is the trailer turned by 45°. The two road edges have a distance of ##\sqrt{2}21' \approx 29.70'##, and the trailer needs 10 (for its own width) plus 20 (half its length) => not possible. If one road is just 20' wide, it gets even worse.

    On the other hand, the satellite image of 32.1956 N, 90.10735 W reveals some curvature. It is hard to estimate numbers for this, but I think it should fit. A better model of the curve would help.

    Isn't it a bit creepy that 3 street names are sufficient to find any location via google?
  14. Mar 3, 2013 #13
    I downloaded a free CAD program. What exactly would help?

    Note that while the road is only 20' and 21,' at the turn the 21' road extends out to the Eastern property line where the 20' road intersects it, i.e., an upside down L.
  15. Mar 3, 2013 #14


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    A really accurate scale plan would help. It looks marginal - no to be ruled out totally so we need to have some really accurate data.
  16. Mar 3, 2013 #15


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    I just found this unposted so I thought I'd post it anyway. The (crude) diagram could help with the discussion.
    I could suggest you pay for it to be delivered to you. If they can't deliver it then you wouldn't have to buy it!
    The "radius" i was referring to is the 'roundness' of the inside of the corner - i.e. at point A on your diagram, there will be some finite curvature on that corner. If that corner is radiused at all, it could make a difference.
    My initial simple diagram assumes the road is 20' wide everywhere and that the trailer is 40' long with perfectly square ends. The crux is at the 45 degree point on the way round.That triangle ( top left) made by the trailer side and the two walls will be 20' from the apex to the trailer side. The diagonal width of the road is near enough 28', leaving you with just 8' for the trailer's width. Not enough unless you can shave some off that corner, have some overhang or use a shorter trailer.
    Having one track wider by 2' and various practical differences suggest that it may not be absolutely impossible but there are other problems like the paths the wheels would take - despite your idea of shuffling it round with a fork lift (you could only get to one end at a time - so you would need two tractors!)
    This is annoying for you because it isn't too far out but you could consider a shorter trailer and that would be really easy.

    Did you ever consider a 'road train' of two 20' trailers in tandem? That would go round with no trouble.

    Attached Files:

    Last edited: Mar 3, 2013
  17. Mar 3, 2013 #16
    There are 36 foot cotton trailers out there. There also may be 40 foot long trailers that are only 8 feet wide. I was hoping to get the big 'un. There is also a back door that I don't have a legal right to use unless my neighbors would agree. Neighbors I don't get along with, unfortunately.

    Good to keep in mind at all times.
  18. Mar 4, 2013 #17


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    @Broken Arrow
    Having seen the satellite view, the situation could well be better than it first seemed. You have a significant radius to that corner. I seriously suggest you go out and measure more details on-site and do the scale model thing. You could even take a 40' rope and place it across the 'worst bit' of the outside curve, then see how much space you have inside it. It will be much better with the inside curve that seems to exist.
    This is obviously a major purchase for you so it may be worth a mock-up experiment, using a 40' timber model (H shaped frame, for instance) carried on a small trailer, if you already have one.
    The extra room that seems to exist on the outside of the curve would help with the manouvering, I'm sure. I can appreciate that the long term economics of a maximum sized trailer would make it preferable to falling back to a smaller one.
  19. Mar 4, 2013 #18
    The rope and H frame are excellent suggestions. Thank you.
  20. Mar 4, 2013 #19


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    Your friendly neighbours will think you've gone crazy! ;-)
  21. Jan 23, 2015 #20
    Hi broken arrow, how did it go? I am in process of getting a 30' cotton trailer on my farm (for muscovy) and am curious how it all went down. I am up north in ukiah and am plotting a similar course with tunnels and other hazards and used the info on this page. Many thanks to everyone who contributed. P.s. my poultry coop is horse drawn so by way of come hee and haw we can side straddle our way through almost any corner!
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