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Mud n' Water - Research for Major Project

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william127:
for the waterproofing have alook at the feb 09 issue of laand rover owner inernational, theres an artical on the marines landrovers :shock:

Suvvey:
Trautman. Were you looking at designing and building a vehicle from the ground up or modifying an existing vehicle for the task?

Skibum346:
Trautman... drop me a PM when you want to chat.

By the way... the video above is the BV202 I mentioned... or at least a version of it.

Skibum

boss:
several factors to take into consideration - as said above the cost and the reliability of a vehicle that isnt too "extreme" almost ought weighs a vehicle built for anything.

tyres.
a few ways of looking at this. super fat or super skinny. the fatter tyres will sit on top of the mud could give you more traction as more tyre is in contact with the ground however if the mud is very sticky the wheels can just spin on the surface. the skinny ones can dig down and get to the harder stuff which could potentially get you out of trouble. but if there isnt anything harder under the mud you have just cut through then its a case of game over.
trewad pattern is pretty much the same story, you can have a super aggressive agri tyre that cleans its self well and digs down to hard stuff but again what happens when there is nothing to dig down too. you could have the best of both worlds by having a fat tyre with an aggressive tread pattern
another upside to the wide tyres is that they will spread the weigh of the vehicle alot more and can also help when you get into strange angles however make things too wide and it wont fit anywhere!

drive line.
if you fit wide agressive mud tyres (as stated) the stresses on the drive line are increased i have heard of people running rediculous rubber on standard axels with no problem but if your making a rescue vehicle then reliability must be righ up high on the list? locking the diffs would also be an advantage in mud,  if one wheel loses traction then all of the drive from the engine will be lost through that 1 wheel spinning.
portal boxes are a HUGE advantage in mud, they do not only increace the diff clearance on the axle but they allow you to get more precice gearing if needs be. most portal axels come with diff locks and strengthend shafts merc or volvo ones are the most popular but companys such as portal tek and D&G tuning are making new hybrid portals from scratch which alegedley have all the advantages of the merc or volvo axels with none of the disadvantages (such as weight or scarceness of parts)

water
baisic princables of water state you cannot compress a liquid if any water made it into your air intake and into the pistons then bye bye engine as it is essentially a big compressor. simple fix is to fit a snorkel but there are other things that need to be done such as breathers for gearbox, transfer box, axels, bell housing and pretty much anything with moving parts, not so much because they will explode but becasue oil and water make an interesting goo with a hidious consistancy that has a tendancy to damage things. if the engine has an ECU then that is something else that needs to be kept out of harms way.

winch
3 main types of winch; electric, hydraulic and PTO
electric winches are very fast easey to fix and easey to maintian and are reasonably cheap but water and electrickery do not mix, solinoids die water gets onto brake drums the brushes corrode can become very problimatic very quickley
hydraulic winches pull for ever, they cant burn out like an electric unit and they are usually lighter and more compact than a lecci one however they can be so slooooooow! not always a bad thing but not always a good thing. if your enginew stalls then you have no winch the hydro units need a pump to work which is normally triven off of the engine via a chain prop or belt or off of the transfer box. if the engine cuts out, stalls or just dies then you have no winch! the pump is not being pumped and the winch is getting no fluid.
PTO (power take -off) winches are mechanical winches which are powerd straigh from the engine they have as much poweer as your engine does they can be very fast or very slow depending on your righ foot, they can pull HUGE loads all day and they are pretty much failsafe. but again if you lose your engine then youve also lost your winch another thing which is quite worrying about them is if you get your wheel caught on something and do not notice it quick enough then thats it the winch will rip it off! no struggleing no straining just gone.

petrol vs. diesel
there is no right or wrong answer here some people sware by there v8s others stick to there TDIs, a diesel is waterproof (given that breathers and a snorkel have been fitted) they have no distributor or spark plugs to get wet and there  maxtorque comes in a little lower. a petrol typically has more power but as staited they dont like water. but there is a way to get around this and that is called megasqurt. this baisically replaces sparkplugs for coils and has an electric distributor and allegedley waterproofs the engine alows you to write your own engine maps improves power/torque improves MPG i dont know too much about this program as i normally stick to diesels but is defnatley something to look at.



that is a pretty comprehencive brake down of offroading through mud and water hope that has helped if you have any further questions you can pm me here or email me(adress is on my profile)

apolagies for any and all spelling errors/bad grammor but i cant sleep and i am ill :(





reguards
boss

Boddle:
 One thing missed here seems to be axle and gearbox breather which are either connected into the snorkel or taken to the top of the vehicle, Having spent a lot of time in water my rear diff pinion bearing has pack up due to water getting into the rear diff via a breather pipe which strangely seemed to be fitted in the rear wheel arch right in direct line of the the rear wheel spray. I now work in JLR driveline design so they shouldn't get it wrong in the future.

 If you are in Coventry area you could bring your question along to the monthly meet held look under pub meets for the next (last Monday of the Month) I am sure there are a number of us who will bore you to tears with does and don'ts.

 Something to think about when designing for water is don't try and seal thing from it unless you have oil in it, water has an amazing ability to get place, a diving bell approach is probably the best Technique here, and avoid electronics where possible.

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