Crawler.. bike buggy..2 seater flat 4 variable diff pro warp

(pete) · Posted: Sun Mar 08, 2009 1:37 pm Post subject:

what about twin starter motors meshing to a cog on the drive shafts

thinfourth · Just got MTs Joined: 24 Apr 2005 Odometer: 257

baloo · Posted: Mon Mar 09, 2009 6:54 am Post subject:

scotty wong · Posted: Mon Mar 09, 2009 9:16 am Post subject:

that looks a lot of fun! if your going bike engine you want a v-max lump(v4 from yamaha) its got lots of low torque sounds like a v8! and got the revs when you need it! car engines are ok but with the gear box they are never going to be light were as the bike is all in one with sequential box! all the staight fours are gutless low down(ive been in a kart with a r1 engine in it) and have to be revved to much.
not sure how to get a reveres though but got to be mechanical the electric is a none starter.

scotty

TheBigPurpleOne · Posted: Mon Mar 09, 2009 9:57 am Post subject:

scotty wong · Posted: Mon Mar 09, 2009 10:02 am Post subject:

jamhod · Posted: Mon Mar 09, 2009 12:11 pm Post subject:

what about a quad engine there light and have revers

YotaDave · Posted: Mon Mar 09, 2009 1:02 pm Post subject:

Now there is an interesting thought. Surely you could fit motorbike engines to a quad g/box?

baloo · Posted: Tue Mar 10, 2009 1:33 pm Post subject:

Mark just sent me this, l will just copy and paste it straight in

.....................................................................................................................

I’m new to this forum melarchy, but with further assistance from the ever helpful Baloo, I thought I
would explain why I built this little machine, what it does well, what needs improving with the
concept, and what I think might be the next evolution in ultra light weight crawlers …..
But first some background … I’ve played with all sorts of 4x4’s in the past, my mate Dave and I
built a 4.5Ltr V8 racer with Jag diffs and lots of tube … (no we we’re that young these were the
neighbours kids)
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We raced it in Egypt …
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It was great fun, it sounded fantastic, but it was heavy, probably about 2000Kg and ultimately
it drank fuel, broke down quite often and got stuck quite a lot !!

You have to make mistakes twice right ?? Well, when I lived in Canada a few years back, I
cut up a perfectly good Jeep and lengthened it by nearly 6 feet !

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Don’t get me wrong, it was great fun (you should try rock crawling and doing donuts in a limo
with 10 people in it) … but again, this was not the diminutive, light weight machine that I knew
a great off road machine needed to be …
So about 2 years back I set out to build the little crawler. The ideas came from various places

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I actually first saw a transverse car engine turned through 90deg and used in a 4x4 at the
royal show about 10 years ago on a big sprayer with a mini engine mounted midship.
I got the idea for a bonded aluminum tub from aeroplane structures, but took the idea
seriously when my father in law used the approach to design Morgan’s hi tech chassis.
The gas springs are a US component and I confess, I have watched my fair share of US
moonbuggy crawlers on U tube …
So the rest is history (documented and commented on above).
So what is it like to drive, what works and what doesn’t?
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Well, lightness is a huge virtue, it helps with everything. There aren’t too many over weight
fell runners !
I managed to get down to 600Kg which means that the little Citroen engine gives about
200Bhp/ton which is more power than needed (yes I actually said that didn’t I). On grippy
slopes that are over about 30deg I can lift the front axle off the ground by burying my right foot
!! Trust me its like a V8 in a 410 you don’t need any more !
The Citroen engine has been a surprising success. Its all aluminium, single port fuel injected,
overhead cam, 2 valve with a surprisingly long power curve and its bullet proof … honestly. It
survives hours of abuse at ridiculous angles without running out of oil pressure (all I do is over
fill the sump 10%) It came straight out of a £30 scrapper, still on its original clutch, cam belt
etc. It has even injested water and its own engine oil (been on the roof 4 times) … simply
take the plugs out, puke the fluids out of the cylinders, plugs back in and vroom…
The gearing is great. 2nd for most activities 1st if crawling is needed and up to 5th for a 40mph
blast.
The general set up has been very reliable … there has been no tub cracking, or tube bending
despite multiple roll overs, including 1 at high speed over the nose being chased by Baloo on a 800cc quad …
I haven’t bust any standard 410 shafts or props … I put this down to light weight …
The only expensive part of the build was those Fox shocks … they are great (make the
vehicle actually) but expensive … what about using motorcross forks ?
So what doesn’t work well ?

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Well the cockpit is snug … the rear visibility is poor … and getting out when its on its roof is
always possible but not always easy. For others wanting to go this route there are various
improvements I would recommend. I will be putting a door in this summer, widening the
cockpit, replacing the seat for one with less “wings” and fitting a removable wheel. There
are also lower profile engines eg Subaru that have been discussed. Also if others use wider
axles with greater track, the whole tub could be larger.
The other changes coming, include the fitment of diff locks. Absolutely essential for serious
trialing I agree but very expensive. I’m going to try to make some poor mans DIY lockers …
I’ll post on how I get on.
I’m not happy with the front axle yet either, it pitches too much and I can’t get full back lock
with 31” tyres so a re think is coming.
Other than that I am thinking about some DIY bead locking as I have to run with almost no air
at all to get any tyre wall deformation and I need to protect the radiator from blocking up so
easily.
So what could be done next to halve the weight of a 4x4 buggy again to say 300Kg ???
Well to do this, the engine needs to be out of a bike (much discussion already about his
above). I would pick a big single or twin, chain drive, lots of torque and either use a quad box
for reverse or convert first gear into reverse rotation (how hard can it be ?)
Next we need to get rid of the axles and the diffs !!! Think 4x4 trial bike with 4 wheel steering
and you get …

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Each corner is an identical casting/fabrication that acts as a single suspension arm (like a dirt
bike). It transmits drive via a chain (like a dirt bike) via a hub CV to allow steering.
I would use bike wheels, tyres and components. The drive comes from 2 angled drive shafts
in the buggy floor using CVs from a small car. The shafts act as the pivot point also ensuring
the chain tension is maintained.
The steering is all done via links (like a Pilot, no heavy steering box / rack). The links run
through the legs to protect them and to present the inner joint along the pivot axis so no bump
steer. Caster, camber and Ackerman angle are also achievable, as is some roll camber.

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I reckon with 4 wheel steering, the lock angles are halved and diffs can be removed.
The driver sits mid ships (Honda Pilot style) with engine and ancillaries either side on the floor
pan (like a go cart).
Drive is via chain to the back shaft (first step down in gearing) with a further chain running to
the front shaft. (no bevel or hypoid drive gears to sap power and weigh too much !! There is
a single in board disc brake …
Air springs at each corner. Good all round visibility, exit via either side. What fantastic
clearance around the wheels
Can anyone think of a better name than “quad-pilot-dirtbike-goKart thinggy ?
Does anyone want one ?
Thanks again Baloo, Mark
.................................................................................................................

sounds like Mark might be joining the ranks of difflock soon

Andy

Kitesurf · Posted: Tue Mar 10, 2009 2:18 pm Post subject:

Thanks Mark for a fscinating insight into your creation. Some great ideas there that make this one of the most read (for me at least) threads on the forum. I like the ultra-lightweight buggy idea using bike components. It is something I have considered but have never managed to get my head round how to drive the wheels.

Thanks for keeping us inspired.

customfighter · Posted: Tue Mar 10, 2009 5:07 pm Post subject:

Awesome idea to make it lighter. Im sure BMW made a bike with single sided swing arm on the front. maybe the front hubs from this could be used or copied

Diesel Destroyer · Posted: Tue Mar 10, 2009 6:00 pm Post subject:

Mark deffo is a clever guy..

I wish Baloo could/ would post pics of his other creations.

He's deffo no 'keyboard builder'

Nigel Head · Posted: Tue Mar 10, 2009 11:27 pm Post subject:

Mark's thinking is on similar lines to the 'Frog' that runs in the Ladoga proto class...

http://www.alaska4x4network.com/showthread.php?t=18673

There's a green one and an orange one, can't find much info on them and by comparison they are big and brutal...

http://www.youtube.com/watch?v=MqjmDU6h_Lw

http://www.youtube.com/watch?v=d33Icu8YXyI&feature=related

Nigel.

minimog · Off-Road Guru Joined: 25 Nov 2004 Odometer: 1700

why not use hydro motors like yamaha used on its 2wd bikes that way you would only need the engine to provide power for the pump unit and the motors could be fitted directly to the hubs without any chains or c/v to worry about Wink

Kitesurf · Posted: Wed Mar 11, 2009 10:39 pm Post subject:

Hydro motors have been discussed before and the consensus was that they are very inefficient. For a lightweight machine the biggest problem would be having a large enought reservoir to ensure that the hydraulic oil stayed cool enough.

baloo · Posted: Wed Mar 11, 2009 10:45 pm Post subject:

here you go

http://forum.difflock.com/viewtopic.php?t=10868&highlight=

l am really digging up the old posts at the moment arnt l

andy

RobotMan · Posted: Wed Mar 11, 2009 10:47 pm Post subject:

Electrickery then?

baloo · Posted: Wed Mar 11, 2009 10:48 pm Post subject:

Electrickerity and water, fizz bang puff Shocked

baloo · Posted: Thu Mar 12, 2009 6:17 pm Post subject:

Diesel Destroyer · Posted: Thu Mar 12, 2009 6:25 pm Post subject:

Them frogs were rumoured to cost a million dollors Shocked

baloo · Posted: Thu Mar 12, 2009 6:28 pm Post subject:

wasent quite the budget l had in mind,

more like a couple of hundred quid for me

teamidris · Posted: Thu Mar 12, 2009 7:08 pm Post subject:

I'll put my my head above the parapet and say;

Hydraulics are not ineficient enough to not do the task!

75% efficient for a normal gear pump or motor, but this task needs a piston swash plate pump (95%), as it has variable flow output. Its an expensive pump, but the torque is a smiler Very Happy

. You can spin both rollers on a 3 tonne road roller, as the engine runs at near full speed all the time. Just jump on the go pedal! And go strait from forward to backward, as any excess pressure is drawn off by cross-line-relief-valves. Don't need any brakes Very Happy

Only real snag is diff locks. If you have four hub motors, but link them to a common feed, the wheel with no traction will take all the oil flow Sad

Can be got around with flow diverter valves Very Happy

I don't agree with the oil volume vs temp. An oil cooler is required to remove the maximum heat generated. The oil volume won't affect the machine overheating, only the time it takes for overheating to occur.

I'd fancy hydraulics over chains Confused

Polaris farm bikes put me right off chains for mud plugging off road use Sad

(motor cross bikes throw the mud off naturally).

Has anyone seen that Jeep that can turn on the spot? The wheels all steer and try to make a circle. Or just force the vehicle into a stationary turn like a bobcat skid steer. Well easy with hydraulics Very Happy

I'd love to see someone as talented as Mark build a light weight hydraulic buggy. No gearbox, shafts, diffs, swivels or brake disks Very Happy

Blue dragon · Posted: Thu Mar 12, 2009 8:40 pm Post subject: Chain / hydraulic

Hi Folks Mark here.

Hydraulics is interesting, although somehow it feels like cheating ! I would be intereted to here about peoples ideas on how to solve the cross flow problem between hubs ... do we need 4 pumps ? I'm also a bit concerned about heat rejection, oils leaks onto the ground etc. I like the idea of using the frame as the oil tank, link arms as pipes etc ... with such freedom what would the suspension look like ?

I share the nervousness about chains, except they are simple, efficient, cheap, fairly reliable. The trial bike guys do prove its a valid approach.

What about toothed belts (like cam drives or Harley Davidson final drive) I think they could be light, and give a smooth drive. As the pulleys are on the hinge point the tension would remain constant. We would have to find a way of hiding them in casings to keep the mud out ... thoughts ?

baloo · Posted: Thu Mar 12, 2009 9:00 pm Post subject:

Hi Mark

welcome to difflock mate, you back from the us now then ?
been having a read through the hydraulic thread have you then ?

why couldent you connect the 4 hydraulic motors in series, that way they would all have to turn together at the same speed, you could fit a simple gate valve across each motor in/out ports so as you could bypass it if it had a problem ?
or you could connect in parallel and use flow divdes as idris says, l biult a 3m press brake and had to use flow divders to get the 4 rams to work in unison so l know they exsist/work

how would you steer ? fold in the middle like a dumper ?
dont know about toothed belts for drive, stones might present a problem

will give you a ring

Andy

jeepmadmike · Posted: Thu Mar 12, 2009 9:10 pm Post subject:

mmm the tread has been dug up again!

i think hydraulics would be fantastic but the down side would be cost, all the clever hydro systems i come across work fantastically well but i dread to think of the cost involved in designing and building them.

toothed belts in sealed swing arms, simple and ideal for the job, a nice little fabrication project.

how about hydro steer using a little electrically driven hydraulic pump?

teamidris · Posted: Fri Mar 13, 2009 7:49 am Post subject:

has to be 4x4x4 with hydraulics as the pipes flex so easily. Take out the CV joint from the hub and put a motor in. Gets you instant portal effect as well. Double wishbone or machfearson is the question?
I guess its expensive, but is it? If you've fitted ARBs thats £1400, then stronger shafts puts on a load more cost, which is a lot less than hydraulics. But the chance of high ground clearance (ref crop sprayer) which you can only get with portals? We've had a few threads on that, and it looks a good way to blow a load of money Very Happy

So is it cheaper than C303? and you can't power skid steer an axel with a common diff, so there are advantages only available with hydraulic, pnumatic and electric wheel motor.
But my favorite bit is the engine position, which is anywhere there is a space big enough Very Happy

Belts in tubes/boxes sounds good. Even if water got in, its not like mud/stones, and there is some shock loading removal.

baloo · Posted: Fri Mar 13, 2009 2:50 pm Post subject:

[quote="teamidris"]

I guess its expensive, but is it? If you've fitted ARBs thats £1400, then stronger shafts puts on a load more cost, which is a lot less than hydraulics. [ quote]

l not sure it is expensive as teamidris says arb's are a whole boat load of money, l wouldent be suprised if you could biuld a hydraulic 4x4 for less than the cost of just a pair of arb's or even one Shocked

these motors were selling on ebay at £30 each when l bought some

l dont know if would be better to mount these high up out of the way and belt drive down tothe wheels/hubs or use wheels with lots of inset and mount these up inside the wheel rim out of harms way ?

trailing arm suspension on the rear might be worth looking at nice and simple, hyd pipes can go down the arm, 1 long air shock and the jobs done ?
is there such a thing as leading arm suspension for the front ??

artic style fold in the middle steering like a dumper would appear to be a simple way to go. but how does that work when you have a roll cage or space frame Shocked

TheBigPurpleOne · Posted: Fri Mar 13, 2009 3:42 pm Post subject:

you could have the roll frame and driver/passengers in one section with the fuel tank and then the engine and hydro pump in the other
joint inbetween