 | Home > My Defender > NATO / Pintle improvement for reversing |
 
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| camelman Member Since: 27 Feb 2013 Location: Peak District Posts: 3372  
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1000s of squaddies have managed for 50 years!
I'd be reluctant to start grinding bits off your hitch. Their short length doesn't help with reversing but I never had a real issue. The last guy who took his grinder to his nato hitch 
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8th Apr 2022 2:18pm |
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| blackwolf Member Since: 03 Nov 2009 Location: South West England Posts: 17372 
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I strongly recommend not grinding anything, learn to live with it.
The main reason that ex-MoD trailers of that general type are hard to reverse is due to the extremely short distance between the centre of the lunette and the axle, which means that any turning happens very abruptly, and the longer the wheelbase of the towing vehicle, and the greater the distance from the rear axle to the centre of the pintle, the harder it gets. It is also, as I am sure you know, a well-known phenomenon, and one which has destroyed lunettes, trailers, and even Land-Rovers, that early trailers (including the narrow-track Sankey) have a rotating lunette and must be towed with a non-rotating pintle (I presume you do tow with the pintle rotation locked? If not, you are dicing with death). It was the appetite for lunettes etc which resulted in the later trailers changing to a non-rotating lunette, which must be towed with a rotating pintle. The problem is that as the trailer's longitudinal axis approaches 90 degrees to the towing vehicle's (approaching a jacknife angle), the lunette rotates, the outer part of the lunette drops below the pintle so that the lunette is vertical not horizontal, and the laws of physics are such that if the vehicle then draws forward the lunette cannot return to the horizontal autonomously. This inevitably results in the shaft of the lunette bending, but particularly on later (i.e., TD5 and TDCi) Defenders will generally rip the pintle off the crossmember or at the very least bend the crossmember. If there is anything jamming in your coupling other than when the phenomenon described above occurs, something is wrong or excessively worn and the problem should be sorted out. The lunette is fairly loose in the pintle, but certainly should not jam at all when horizontal. There is no doubt that reversing an ex-MoD trailer of this type is exceptionally challenging, especially on rough surfaces, but it is also extremely satisfying when it goes well. |
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8th Apr 2022 3:16pm |
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| MercianRover Member Since: 07 Apr 2022 Location: Culworth Posts: 141 
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camel man
More likely the security clip wasn't in place. I'd bet most of the cases there is more than one squaddie about to manhandle the trailer and they aren't manoevering amongst parked cars. blackwolf Understand the physics and that such laws can't be defied. Inspecting the pintle and lunette they are in excellent condition (former was new, latter very little use). There is a centredrill mark on the lunette from where a revolving centre was used when the shaft was machined. The pintle has a flatter land where the lunette rests on the overrun. My thought was to dress this a little more concave but I suspect that won't work because of the potential perturbing off-centre forces when reversing. Probably easier to fit a removable pintle on the front bumper. |
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11th Apr 2022 1:36pm |
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| blackwolf Member Since: 03 Nov 2009 Location: South West England Posts: 17372
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A front coupling does make manoeuvring a trailer, especially a short trailer, very much easier. I have front and rear 2" receivers so any coupling can be fitted to either end.
My "proper" NATO pintle is fixed to the crossmember at the rear, so if I need one at the front I use a second one on a slider, but for a more portable option a pin and jaw coupling large enough to accept a NATO lunette, again fitted to normal DB slider, can be used. Manoeuvring caravans at the front can still be pain due to the difficulty of seeing past them, which is the reason that people quite often mount front couplings in line with the n/s chassis rail, but for interesting trailers (I'm afraid caravans are not interesting IMO) centre front is ideal. |
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11th Apr 2022 2:23pm |
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