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Post by Peter Seager-Thomas on Jul 29, 2012 11:22:42 GMT -5
A discussion thread to exchange ideas, opinions etc. As Andi says, such features are added on occasion regardless of whether they help performance or not. I once read that front ends of the best performing cars are fully supported by the guide, the front wheels only touching the track on corners to prevent the car tipping over. The perfect reason for adding such features must be 'because you want to'. There are three areas where I am working. The first is simple and by no means new, and combined with my second. I'm working on independently turning front wheels (on ball bearings) combined with steering front wheels. Regarding this project, size does count, the smaller the better in many areas. I will be using the largest bearings which I can accommodate in the 'brake drum' of the wheel, thus with the large O/D, rock on the wheel will be much reduced. The bearings will lose their shields, be flushed out and probably run in light oil. The steering is complicated due to the possible use of a highly visible beam axle, and the need to keep parts small. Parts for the first assembly have been started, though I have no idea which will be the first car they appear on. The third area regards suspension. Below is the picture referred to by Andi. My own idea is to have a bash at a swing axle type suspension as used on several pre-war GP cars. This will involve twin in-line drive pinions driving a crown wheel on each axle. Different sizes, but the same ratio. The axles will use the pinion centre line as their pivot point. Certainly one of the problems with potential projects is the parts. I will be doing a diff. at some time, so ensured that I bought some bevel gears from John Robinson when he had his clearout. Try looking for miniature bevel gears these days. RS have tiny 2mm bore U/J's but at prohibitive cost, fortunately miniature bearings are in common use and are just a few pounds each. Peter.
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Post by Andrew Rowland on Jul 31, 2012 0:59:13 GMT -5
Nice thread Peter.... Its been pointed out to me that my remarks might have appeared without humour so I just want to apologise - I was only prompting your response which you duly gave with this fine thread so I hope you didn't take me too literaly. I'll post some more 'discussion' when I find a moment. Cheers Andi
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Post by Peter Seager-Thomas on Jul 31, 2012 10:59:01 GMT -5
No problem Andi, though I am considering going off in a huff on principle.
Peter.
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Post by Andrew Rowland on Aug 1, 2012 23:13:14 GMT -5
so with one hand while i hold the baby.....
Why? (my reasons)
now in slot car land there is this thing, particularly with the generation who were actually there in the 60's that the limited physics involved in slot cars has all been sorted and if you follow a few simple rules your car will be 'the fastest'.....
while i'm certainly not suggesting those 'rules' are wrong i do believe that we should continue to experiment. i don't believe that, with all respect to engineering and modelling skills and techniques of the '60's, today there can't be new things to be learnt and evolved...
plus its fun - i don't really race as there are no proxy f1 classes for the 70's and very few actual races at all.... so i like building and testing my cars.... for a race 4wd might be suicide but that might also depend on the track??
then why is it that an nsr rtr made today in plastic will probably beat any scratchbuilt hardbody car? because they adopted some of the early principles and added today's manufacturing and engineering, surely?
also i like a challenge and i like to learn about the car i'm building and in my own way try to imitate what the original designer was doing in a slot car version. you might have noticed i'm very little interested in drivers or the minutae of finishing details and much more interested in how the car worked and how that could be 'reflected' in an electric car running in a slot at 1:32 scale....
Diffs then....
so diffs are for me a fascinating subject. slotcars run better without them right? how many of you have actually got first hand experience of that? slotcars are more like go-carts right and they don't have them! yes but they don't have them as they're better without or because that 'formula' was designed to be low tech, small and cheap? do you know the answer to that really?
i've driven my vanquish lotus 72's a bit and i have to say that i reckon its a little bit like the lotus 56 turbine...... as graham hill said you have to completely forget how to drive a conventional car and learn how to drive that car! but there are in my opinion possibly some advantages??!!
how many people really tried 4wd or diffs in the top rung and then kept practicing and instead how many people immediately shelved their latest idea simply because they got beaten by a rattle plate or whatever style won that year.
so maybe 4wd is a waste of time - i wouldn't want to say i knew better than 50 years of evolution but i do believe that as time passes old ideas need to be questioned with new technology...
how - now - me
so from the 80's in rc they've been using 'ball' diffs. exactly like a normal diff but with perfectly round ball bearings set between two perfectly flat plates. the genius is that friction is very very low - no cogs. and that the amount of slip can be controlled simply by increasing the pressure between the bearings and plates. before you ask yes it works, all rc cars have them
now kyosho have a line of 1:43 rc cars called D-Nano and it happens that they produce a lovely little ball diff for that, so i'm gonna give that a try.... no availability of bevel gears a problem now! and no problem fitting it all in! they're fairly costly but to be honest i've never managed to build a car for less than about 300 euro anyway given the cost of postage to italy....
so that's it for me: a - engineering for engineering's sake - yes sort of b - some like going fast - others like other elements of the hobby c - old ideas should always be tested d - using new techniques, in my view
PLEASE discuss - no point in one person 'ranting' if the rest don't get involved....
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Post by Mark Huber on Aug 1, 2012 23:53:51 GMT -5
a+b+c+d=e
where e= it's fun
We may have different definitions for a, b, c, d and whatever else goes into why we do the things we do as we pursue our hobby, but I'll bet for all of us.. the elements always add up to "e" and "e" always = it's fun.
Go for it Andi. Some of it will be successful, some of it perhaps less so, but as long as you're enjoying the process (and I'm pretty sure you are), it's more than worthwhile.
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Post by Stubbo on Aug 2, 2012 2:26:24 GMT -5
This sort of discussion touches on things I have very little knowledge of but I do find it absolutely fascinating and interesting.
Learning all this new "stuff" is probably the thing I enjoy most about the hobby at the moment. In the last few years I have learned so much about a whole range of topics that I never knew anything about. And all because of slot cars.
So I can't add a lot to a discussion like this but please guys keep it going. I am eager to learn.
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Post by nuvolari on Aug 2, 2012 5:20:06 GMT -5
Hi there, It's really nice to see Andi's passion for engineering. For me it's the same as Stubbo, is way out of my league, but I understand the principle. Personally I don't think, I'm ever going to go that far in engineerings features. For me the history, the race figures, the evolution of car development, brought together, and finding new scratch building techniques, building a beautiful finished model, is to me the challenge and passion. Even the racing it self, isn't of that much importance to me. The engineering part stretches only that far, that I'm always glad to find a suitable motor and suitable standard gear. Although, if you count track following front wheels under engineering, that far am I willing to go, because to me, that gives a big influence how the car behaves it self more realistic in a curve. But that's each individuals passion in the slot car world, but it's always fun to read about other peoples passions and discussions, so keep on doing this people It's fascinating to learn about the experiences and the evolutions they cause. Andi, I hope we learn more about your new kyosho D-Nano system, with lots of photos of the engineering part and an objective view if it makes such a big difference in performance and driving style. Keep us up to date and don't forget Mark's e factor . Cheers, Danny
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Post by Peter Seager-Thomas on Aug 2, 2012 9:29:26 GMT -5
I have read about the Dnano cars with interest, and note that they do occasionally come up on eBay secondhand, with controller but often minus battery for under £100. A lot of money just to play around with it as an experiment, but of course my first wheel etches cost almost £200 and I didn't know they would work, I just felt they ought to. From my point of view, two distinct forms of engineering apply to this thread, those to make the car perform better, and those to make it look right. My logic (?) suggests that for performance, Chris's Mk 3 chassis would do the job, which is a pivotted front end with torsion bar springing. Indeed I like the idea so much I'll have to play around with some bits of brass and piano wire... 4WD. I'm pretty sure 4WD MRRC Mercs were regular championship winners years back. Several years ago I raced 1/8 R/C cars, the 'track' was a very flat warehouse floor and the 4WD cars always won. For me, it is getting the car to look right. I had Airfix in the 60's, friends has Scaley Formula Juniors. Then one came along with a new car without steering. For me, it doesn't look right, especially with a slower car where you can actually see it properly. Cars with enclosed bodywork are of course, different to a degree. I don't think anyone has done a 'steering kit', presumably because there is no demand. I know Al (Penrose) has done some experiments, and also Graham (Poulton) had some parts made. Slot-it do suspension bits, Vanquish have done their 'diffs', but generally I think it is up to the scratcher if he really wants the bits. This is my swing axle idea. The light blue and green parts are the swing axles, the red parts are the (chassis mounted) pivots for the arms/bearings for the drive from the motor. The greatest limitation would be the limited full bump without grounding which could be avoided with the introduction of 1:1 gearing on input and output to raise the whole assembly but leave the input and output drives at the right height. Only appreciated if a hump-back bridge is incorporated in the circuit... Peter.
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Post by Andrew Rowland on Aug 2, 2012 11:43:42 GMT -5
You're a very lucky man Mark if this is fun, for me its THERAPY...
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Post by Mark Huber on Aug 2, 2012 12:15:01 GMT -5
Well Andi, a) I'm not a scientist, an engineer, or an architect, therefore b) my list of a, b, c and d are basic and simple I still keep a cheat sheet to remember what high gearing and low gearing really means. I tend to mix them up. Like Alan and Danny, I really enjoy seeing what folks like Peter and you come up with, even when it's way over what I'd ever think about or attempt. I am more than willing to copy a great idea (provided it's not too complex) and I'll still applaud the ideas and efforts that are complicated. Ps: Therapy is good thing especially if it's working! (And I noticed you mentioned fun in your essay.) Now.. I have to go back and see if I can understand Peter's swing axle diagram. Give me a day or two.
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Post by Deleted on Aug 2, 2012 16:22:00 GMT -5
I can't understand Peter's diagram, Mark. Probably because it's done on a computer, rather than with a pen or pencil. It seems to be overcomplicated simply because of the way in which it is rendered. Come on Pete, gimme a scratchy old pencil sketch!
Martin
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Post by David Lawson on Aug 3, 2012 1:29:10 GMT -5
I think the drawing is either an Aztec design or a map of Hampton Court Palace Maze or am I missing something....
David
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Post by Peter Seager-Thomas on Aug 3, 2012 2:20:09 GMT -5
The original Hampton Court maze had swing axles.
Peter.
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Post by nuvolari on Aug 3, 2012 4:30:19 GMT -5
Hi Peter, I’m also breaking my head, like so many others, on your drawing of the swing axle idea. This is how I understand it: The red parts are fixed shafts on you chassis. The yellow axle, is the axle that is mounted on you motor, and on that axle there are two pinions mounted, an 8 tooth and a 10 tooth (black) The 8 tooth is connected to 24 tooth gear in (dark green) that sits on an axle (dark blue) going to one wheel and on the other side the 10 tooth is connected to a 30 tooth gear (purple) going to the other wheel. The light blue and – green parts is the housing of the running gears and can swing around the axle coming from the motor giving each wheel an individual suspension. I hope I got it right so far? But what breaks my head is the difference in gear ratio between both sides. If both gears touch the motor axles pinions, than you would have one wheel going faster than the other? If your gears are allowed to move around and only one gear would touch the pinions on the motor axle, depending the car swings to the left or the right, than you car would constantly side wind? Perhaps I got it all wrong, but if some one try to explain something I also want to understand it. And David, I don't think it's the Hampton Court Palace Maze, I've been into that one, and it wasn't that difficult ;D Cheers, Danny
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Post by Peter Seager-Thomas on Aug 3, 2012 6:14:08 GMT -5
You got it Danny.
Gear ratio's?
8:24 = 1:3 10:30 = 1:3
Both axles are driven at the same speed...
Peter.
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