bishbosh Posted August 30, 2010 Author Share Posted August 30, 2010 Aren't bank holidays great? Managed to escape to the garage for a bit today and glued some more bits into the space frame. Except for suspension mounts and panelling, it is more or less complete. Well, except for about a week with a dremel / power file / hand file tidying up the welds! Still trying to decide between four link or two link with panhard rod....... Quote Link to comment Share on other sites More sharing options...
steve b Posted August 30, 2010 Share Posted August 30, 2010 Niiice , , 4 link has to be the choice , with adjustable links to set it all up for racing or crawling Most satisfying I should think Bish , and at this rate you will be finished before Mr W cheers Steveb Quote Link to comment Share on other sites More sharing options...
landrover598 Posted August 30, 2010 Share Posted August 30, 2010 mmmmmmmmmmmm, uber smart, but can we have other things in the photos to get an idea of scale ? Quote Link to comment Share on other sites More sharing options...
Turbocharger Posted August 30, 2010 Share Posted August 30, 2010 Dave - how much more scale do you need? The lawn is about 4" long because he's been in the garage rather than out mowing... Bish - Looks fantastic, like a spatial awareness challenge! I know there's a temptation to triangulate everything and add weight, but the four parallel bars at floor level are crying out for an X-brace? But then, how much force is it going to see, really? Quote Link to comment Share on other sites More sharing options...
bishbosh Posted August 30, 2010 Author Share Posted August 30, 2010 mmmmmmmmmmmm, uber smart, but can we have other things in the photos to get an idea of scale ? It is 770mm end to end Dave - how much more scale do you need? The lawn is about 4" long because he's been in the garage rather than out mowing... Bish - Looks fantastic, like a spatial awareness challenge! I know there's a temptation to triangulate everything and add weight, but the four parallel bars at floor level are crying out for an X-brace? But then, how much force is it going to see, really? Not worried about weight - it is all 10mm solid bar!! The floor will be filled in with 2mm sheet to form a skid plate. Got to sort out driveshaft angles before I do that bit though.... Oh, and I cut the grass on Friday... Quote Link to comment Share on other sites More sharing options...
elbekko Posted August 31, 2010 Share Posted August 31, 2010 That looks very nice I wonder if I can make those Boggers fit on Lego wheels Quote Link to comment Share on other sites More sharing options...
MECCANO Posted August 31, 2010 Share Posted August 31, 2010 how much force is it going to see, really? Nice work bish. So whats the power plant going to be, sorry if you have already said. Quote Link to comment Share on other sites More sharing options...
bishbosh Posted August 31, 2010 Author Share Posted August 31, 2010 Power will be electric - but things have moved on a bit lot since I lasted had an electric RC car......I think a 540S was the dogs danglies back then. With all the talk nowadays about kV and 3S this and that........befuddled Quote Link to comment Share on other sites More sharing options...
Turbocharger Posted August 31, 2010 Share Posted August 31, 2010 Looks like it might be a bit too strong, and there's some strength / weight that could be taken out? Quote Link to comment Share on other sites More sharing options...
MECCANO Posted August 31, 2010 Share Posted August 31, 2010 Power will be electric - but things have moved on a bit lot since I lasted had an electric RC car......I think a 540S was the dogs danglies back then. With all the talk nowadays about kV and 3S this and that........befuddled Its all about brushless and lipo batteries these days. Either that or Nitro powered engines But the fumes make you go Crazy Quote Link to comment Share on other sites More sharing options...
landroversforever Posted August 31, 2010 Share Posted August 31, 2010 IMHO Nitro doesnt have a place in an off roader of this type, unless you're going for the trophy/rock racing type. Quote Link to comment Share on other sites More sharing options...
MECCANO Posted August 31, 2010 Share Posted August 31, 2010 IMHO Nitro doesnt have a place in an off roader of this type, unless you're going for the trophy/rock racing type. Depends how you go about it, if you get the gearing right... or you create a nitro powered generator to drive the motors... Or even a hydrualic motor driven by the engine, which can then be used to assist the steering... if you really want to get technical. Quote Link to comment Share on other sites More sharing options...
bishbosh Posted September 1, 2010 Author Share Posted September 1, 2010 It definitely will not be nitro - far too flaky and reverse and braking are more complicated. firmly decided in favour of electric - just need a 12 year old to explain it all to me and work out what bits I need! Quote Link to comment Share on other sites More sharing options...
MECCANO Posted September 1, 2010 Share Posted September 1, 2010 It definitely will not be nitro - far too flaky and reverse and braking are more complicated. firmly decided in favour of electric - just need a 12 year old to explain it all to me and work out what bits I need! I use to think that two, but a decent Nitro engine made by some one like O.S. will run all day and all night, wont over heat and cut out, wont stall and will even run fully submerged with a snorkel and power supply to the glow plug As for reverse and braking, you can buy a HPi savage auto 3 speed box, with the addition of a reverse module. It even includes a transmission brake. Or any of the Traxxas nitro engined truck transmissions. I'm not anti-electric. I have more electric models than i do Nitro. My scale 4x4 is a 3 speed tamiya with a good old 540. I just get fed up with having to lug 6+ battery packs around for a decent duration run ( as well as the wait for them to charge) When you can just fill up a tank( which is the equivilant of 3 batteries), and with a few strokes your away. Quote Link to comment Share on other sites More sharing options...
bishbosh Posted September 1, 2010 Author Share Posted September 1, 2010 So do you know any bright 12 year olds to explain what motor / esc / transmitter I will need for a 25lb crawler cum rock racer...? Quote Link to comment Share on other sites More sharing options...
landroversforever Posted September 1, 2010 Share Posted September 1, 2010 Transmitter depends on what things you want to be able to controll? just steering/throttle or more? the RC world seems to be using the 2.4ghz stuff more. Saves faffing with crystals etc. Motor/esc - worth having a look on www.rccrawler.com in the large scale section of the forum Quote Link to comment Share on other sites More sharing options...
MECCANO Posted September 2, 2010 Share Posted September 2, 2010 So do you know any bright 12 year olds to explain what motor / esc / transmitter I will need for a 25lb crawler cum rock racer...? Transmitter wise, if you just wnat forwards and backwars, left an right. Just stick with a 27mhz 2 channel by some one like Acoms (they have never let me down) Futaba 2 channels aren't as robust in my honest opinion. If you want to have operating winches lights etc... Or even a exhaust smoke generator you will need more channels. If your getting into 4ch upwards then futaba are pretty good. You will need a 40mhz for land ( 35mhz is for sky and usign it is a big no no) When you get itno 4 channels you also need to take note of the self centre. On heli's etc the left hand ( up and down motion)stick isn't designed to self centre, but for throttle you will want it. There are a few cheap 4 channels sets now ont he market designed for use on cars/ trucks so have this already sorted. For motors, if your planning on usign the standard 540 brushed type, basiclaly the higher turns ration the more torque and the better it is for your application. A standard 540 that would come in a kti is 27 Turns if i remember correctly A standard economy style electronic speed control will almost always be able to handle atleast a a 27t. Speed controls work kind of backwards to what you want. Basiclaly as a motor gets Faster you have less turns... but as a result higher current draw. So the lower the turns rating a speed control can handle. The better it is. In your case. Because your going for higher turns ( more torque, less rpm, and alot smoother controlled running)it doesn't really affect you too much. There are speed controls similarly designed for trucks/ rock crawling and even dual motors if your still unsure what you want. the only other thing to consider on speed controls is the reverse/brake setup. Cheap ones don't always have reverse. THey may have electronic brake instead. Ones that have both brake and reverse tend to operate so that you have to hold the brake for a few seconds before the reverse will operate. For rock crawling you don't need a brake, only forward and reverse. and you don't want a delay either as its really annoying but you mgith struggle to find one with out a brake. Also you might want to get a water proof speed control. Although most regular speed controls can handle a fair bit of dunking Hope that makes some kind of sense. For example a good Motor: http://www.modelsport.co.uk/?CallFunction=ShowSpecification&ItemID=37684 Speed control (a ctually had this one): http://www.modelsport.co.uk/?CallFunction=ShowSpecification&ItemID=33292 Transmitter: http://www.modelsport.co.uk/?CallFunction=ShowSpecification&ItemID=35091 Quote Link to comment Share on other sites More sharing options...
bishbosh Posted September 2, 2010 Author Share Posted September 2, 2010 Hmmm, thanks for that. Methinks some more research is required before I understand all this! Quote Link to comment Share on other sites More sharing options...
MECCANO Posted September 2, 2010 Share Posted September 2, 2010 Hmmm, thanks for that. Methinks some more research is required before I understand all this! Heres the easy option. Although a tad pricey Combo package I'm probably over complicating things. If you just want to keep things simple ( and more than adequate for what your doing with the right gearing) then just use a standard motor, and a cheap elec speed control. Standard tamiya motor Cheap water proof esc I use a stock tamiya motor in my scale 4x4, and a speed control from the above range, was more than capable for zooming around the woods up 60 degree inclines and wading through thick mud. Quote Link to comment Share on other sites More sharing options...
bishbosh Posted September 3, 2010 Author Share Posted September 3, 2010 My concern is will these motors be man enough for a model that is going to weigh 25 - 30 lbs? I don't mind spending money for the right gear - prefer that to spending a little on stuff that is no good. Quote Link to comment Share on other sites More sharing options...
GBMUD Posted September 3, 2010 Share Posted September 3, 2010 One of these would be up to the task then Bish? Quote Link to comment Share on other sites More sharing options...
MECCANO Posted September 3, 2010 Share Posted September 3, 2010 My concern is will these motors be man enough for a model that is going to weigh 25 - 30 lbs? I don't mind spending money for the right gear - prefer that to spending a little on stuff that is no good. Yeah your probably right. Most the fast off road electric monster trucks ( that probably weigh half that) have a dual 540 setup. Or a super brushless motor. Are you using it for pure rock crawling style driving, or do you still want to be able to thrash about with a bit of speed? Are you planning on making the transmission your self, as i think that might also be a big consideration given the weight. You might find it difficult to get the power you want down with out stripping teeth of most existing model gear boxes. Quote Link to comment Share on other sites More sharing options...
bishbosh Posted September 3, 2010 Author Share Posted September 3, 2010 I will be building my own gearbox - all part of the fun! Hopefully it will be two speed so I can crawl in one gear and pratt about on the beach etc in the second. Chris - no good mate - would be rubbish on side slopes Quote Link to comment Share on other sites More sharing options...
Night Train Posted September 3, 2010 Share Posted September 3, 2010 Why bother with toy motors when you could use a motor, or two, from a golf cart or mobility scooter? You can even get a decent controller from one and use the RC stuff to work the throttle pot. How about this one with a shaft to each axle? Or you could use a winch motor. Quote Link to comment Share on other sites More sharing options...
Quagmire Posted September 3, 2010 Share Posted September 3, 2010 I think you'll need brushless and maybe some gear reduction to get the torque you'll need for shifting that weight. Then again I might be wrong. However, if I am right I have no clue about brushless as I have never ventured into that territory, it wasnt around when I used to properly muck about with RC, and my recent dive back in has been with a Tamiya Tractor unit, so I went the easy route and fitted a 55 turn brushed motor I use a Futaba 4EX transmitter on the Scania and am very happy with it- programmable end point adjustment, sensitivity etc, feels nice too- four channels. I'd take a trawl around scale4x4rc.org and see what other peeps there recommend for power... For reference, the tractor unit weighs (according to manufacturer) 3.2kgs, the trailer is 2.5kg, and I can quite happily haul around 5 litres of Orange juice with no probs (so call that 5kg- not sure on density of Orange juice but cant be far off water). It does have a 3 speed though, and setting that weight moving will normally require 1st or 2nd gear. Stopping it can be fun. Gratuitous truck pic : Quote Link to comment Share on other sites More sharing options...
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