When an Engineer… Part 2

[Aaron]

I have recieved a further update!
—
I was quite chuffed to see my story in AUSMICRO, and didn’t realise the interest it would cause, I will continue (if that’s okay) about other developments with these addictive little cars.The biggest hassle with these vehicles is the steering (non-proportional) so it’s either left or right, but wait a minute, there is a number of changes that can be wrought to address this, however the following is only my considered opinion and could be quite wrong. It was important to set up an environment that suited the car, so a 4metre x 1metre track was made from MDF and light timber, with black board paint as the tarmac. ( main straight and slow “S” back to the start) It was near impossible to negotiate the 150 mm wide main straight and the corners were worse.HMMmmm..obviously it would help if the steering was speed related, and so-much testing followed,the castor or trail was increased to 1.8mm and the distance from king pins to steering link was also increased to 3.5 to recover lost leverage, a guide plate was fitted under the steering link so it was no longer influenced by any axial (up down) movement of the axles, the 1.5mm dia axles( 12ba screw which are easily removed )are now 14ba or 1.0mm dia, this alone reduced surface area by almost 25%( blowing on the wheels sets them spinning easily). It should be mentioned that they don’t have true progressive suspension but merely a pivoting weir that enables ALL wheels to contact the ground with relative even pressure, it was essential that the centre-ring spring didn’t drag any where and was free in it’s pivot, it’s free end gap is 6mm, it is also absolutely critical that no slop exists in the steering system!! All this was completed for only one reason and that was to make the steering 100% reliable and consistantly straight. If it can achieve this then plotting a course only requires you to power off or turn in what ever sequence you choose at a particular point on the track – bearing in mind that as battery voltage falls the steering becomes less reactive.The contoller came in for mods as well, being of the pivoting joystick type it had lots of over-throw so limiting screws were fitted to just allow reliable contact, this reduced the human error factor to a minium. This next comment may be discounted by those in the know however, if the car is travelling straight forward at 4 k/mh with all wheels concentric (spinning dead true) and have relative even contact with the surface and a command to turn left is received, initially the response is poor due to the resistance leverage of the wheels (equally trying to bend backwards) castor or trail plays its part here, and the magnet being at mid travel and of low attraction, the magnet then starts to move to it’s coil and the inside wheel can now over power the resistance of the outside wheel, and then it all happens too quickly! It was thought that if the front tyres were slightly tapered with the largest diameter close to the car, some weight transfer to the outside tyre during the corner would increase contact therefore resistance and it’s reluctance to pivot, the inside tyre would have reduced contact and low leverage influence therefore increasing the turning circle, this is obvious while watching the cars turning circle increase as speed is increased (my cars have eccentric steering link bushes, an absolute Godsend as a slight amount of toe out is handy). And so ?? The results are hard to believe, but with only a few practice laps I found the car easier to control under constant normal power than inching it with on/off commands, (initially this must be done to lower the voltage a bit). Three laps were completed with only the slightest contact with the wall at one place, and a total of 9 laps before a spin out and a further 8 laps before a flat battery, phew!!! exciting stufff! Boost can be used if your game.( a 7mm ball bearing was stuck to the bonnet above the front axle with plasticine and this really made the steering slow!) A standard out of the box TOMY char-g Honda was applied to the circuit……it’s battery went flat by the time it completed two laps, there was no directional reliability at all..it was rather sad really.I hope to do some lap times and battery endurance tests soon, I’ll keep you informed.

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A.

--
Site Owner Guy.

[merc-blue]

hello mr engineer can u take pics of all this ??? cause its all starting to sound a little well wrong.. no offence

[z-beam]

pics would be nice but a purchasable differential to suit a tomy bit char-g (on the standard ratio) without having to modify the chassis would make my day, and increase my enjoyment of the hobby a thousand-fold.

what would the diff alone be worth? if it was possible to fabricate a limited run i’m sure the items would be quite collectable and sought after peices…

pleeeeeze!!! look at my tracks and see why i need 4 differentials for my cars to steer evenly!!

[Pork_Hunt]

Engineer dude should become a member!

[jamiekulhanek]

i worked out a simple way to make a ball diff, but the mechanism to retain tension in it was the hard bit to figure out….until betty suggested magnetism!

Z-beam, why do u need 4 differentials ina car??

[z-beam]

yeah i think it was that prof. farnsworth who did a differential for a bit using bearings, steel plate one side and a magnet on the other using the tomy gear in between.

[TOYO]

Quote:

pics would be nice but a purchasable differential to suit a tomy bit char-g (on the standard ratio) without having to modify the chassis would make my day, and increase my enjoyment of the hobby a thousand-fold.

what would the diff alone be worth? if it was possible to fabricate a limited run i’m sure the items would be quite collectable and sought after peices…

pleeeeeze!!! look at my tracks and see why i need 4 differentials for my cars to steer evenly!!

[merc-blue]

hey toyo welcome to the forums… yeh we all want to see this stuff it all sounds soo good

[TOYO]

SORRY ABOUT REPEATING REPLY ABOVE,I’M A BIT DIM ON THIS INTERNET STUFF, AM TRYING TO SEND PHOTO’S–BUT THE CARS AND PIECES LOOK SO SMALL, DON’T KNOW IF YOU HAVE CAPABILITY TO ZOOM.

[merc-blue]

oh ur the famous man who did all this… cant wait 2 see some pics

[TOYO]

AM TRYING TO UPLOAD IMAGES IN MEMBERS GALLERY, BUT KEEP GETTING TIMED OUT ERROR ASP 0113, OBVIOUSLY SOMETHING ELSE TO BE LEARNT, WHAT AM I DOING WRONG??

[betty.k]

it’s possible the pics are too large. check the file size constraints and resize accordingly:8ball:

[Admin]

hey everyone

[Admin]

i have a few ?s that im hopin some of you guys cud answer
on the microamps website it said the zz se cudnt have the set 2 fet mod, only set1, why is that?

[z-beam]

hey big head! welcome…pm microamps about that question please. this thread has nothing to do with zip zaps, or fets.

welcome toyo: the images you download should be optimized for web usage. with a good digital camera some photos are way bigger than you think, the first couple i managed to get online where A3! way to big for most applications.

using a program like photoshop or photodeluxe usually let you modify the pictures by saving them for use on the internet. cropping unwanted details, resizing and jpeg compression are all recomended for ease of downloading.

good luck, and i am anxious to see you feats of engineering!

and by the way, any chance of getting a differential made:smiley2:

[merc-blue]

toyo jest email them to the admin guys and they will put them up for u

[TOYO]

Am wrestling with conscience about this question of making transmissions, as stated before it is not economic, diff’ will take 3 hours,housing about same and then chassis must be modded to suit, to reap benifits of trans steering must be o/hauled as well, have just finished new car that has no layshaft(motor pinion drives diff’ directly, motor pinion is 1.26mm dia with 6 teeth-need eyeglass to see it!)with rear suspension.Have drawn on cad and could be 4 axis machined on cnc,still gonna be $$$$.

[TOYO]

Thanks for help troops, have uploaded with success (I think)images in member gallery.Would also like to thank good folk at AUSMICRO Greatly appreciate this opportunity to show pics, “arigato gozimas”.

[Aaron]

TOYO!

I was checking out some other stuff and just checked out your Gallery. Well done! The pics probably don’t do the amazingly fine and intricate work justice.

Keep on posting! As for costs, remember you have somethign unique and that in itself makes it exclusive, you’d be surprised how much people would pay for that!

A.

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Site Owner Guy.

[betty.k]

well i’m impressed! i’ve always favoured the enertec chassis for modding and it looks like you’ve taken it up a notch (or 2!!):8ball:

[TOYO]

The enertec’s have proven 100% reliable electrically for over two years,motors however are very efficient-output shaft bearing only phone’ vibrators,the commutator end is unsupported and suffers poor contact after about 3 hours use. New type car was briefly tested today and is knock out compared to prototypes, has lotsa’ major changes,sprung and sealed delrin trans’ housing,motor drives alloy diff’directly thru’ single 11-1 reduction,flywheel equiped motor to smooth out horrible 6 tooth pinion vibration (turning 35000rpm on boost)front fluff resistors and axle boxes made from one piece,all steering bushes are alloy, centre-ing spring pivot removed from above magnet and mounted in top plate, double sided cam screwed to steering link to allow adjustment of spring end gap,adjustable turning radius cams, toe in/out eccentrics and original alignment eccentric,Ackermann offset is .25mm(this makes inside tyre turn tighter radius than outside reducing scuffing).Car is 8 grams lighter on rear axle but only 2 grams lighter on front, original 5mm wide tyres reduced to 4mm and front wheel dia increased from 13mm to 13.5mm rears are 14mm(Wheel spin is concerning).Curious fault of prototypes was inside rear wheel momentarily spinning backwards while cornering,to overcome this delrin(nylon-non magnetic)4 turn helical spings 4.8mm long made and fitted with brass thrust washer mounted on kingpin shafts,original seesaw device removed and as mentioned rear floating axle,differential packed with light grease. Have been unable to asses this as yet but car tracks near perfect on cement driveway compared to prototypes bouncing all over the place,can’t wait to test on track and hopefully crack 55 lap-7.8minute endurance set by prototypes.My apologies if this subject bores crap out of everyone.

[betty.k]

speechless!:8ball:

[jamiekulhanek]

Fluff Resistors…LOVE that word!

Quote:

My apologies if this subject bores crap out of everyone.

*Cough* WHAT?? Are you kidding, this stuff is so exciting that it makes me sticky in the panties..

Um so are you gonna make any of these for selling?

My ZZSE is DYING FOR this stuff!! Oh, wait, so am i!

[rashumble7]

I second that, only thing no panties just boxers:approve:. That is some sweet stuff you have there TOYO :shock:, why dont you open up a home page and show pics from different angles.

Cant wait to see more

[TOYO]

Have uploaded more images in member gallery,I can’t find an easy way to tell price all of this,as much as I would like to build micro’s all day, Japanese business comrade(wife) won’t let one out the workshop for under A$550 + GST.Jesus wept,personally I think the money better spent on 2 Mini-Z, I hear they are unbeatable. Interesting thing about proportional cars-bought first one after 8 non prop’types(Tamiya FF02 Celica)wife said it would be faultless Japanese quality, we were both disappointed,now has alloy front chassis, single reduction right angle drive, variable brush gear timing, splined drive coupling,teflon sealed suspension, zero tolerance ball joints etc,etc.Runs for 22-26 minutes and easy 28-30 km/h.But needs enormous area to operate and too much manual dexterity to drive smoothly,at moment prefer simple twitching thumb control.

[z-beam]

i’ll try and find a siple design for a diff that probably wont be as good as your amazing engineering job toyo, but might be quicker and easier to make.

a differential that could be used on a standard bcg chassis would be a marketible item, say using a simpler ballbearing and magnetic system that uses standard tomy gearing would be exelent.

as for mini-z they sure are an amazing piece of equipment. very responsive and once given bearings,c-f h-plate and better tyres is great fun to drive.

[jamiekulhanek]

In my experience with mini Z’s, i have found essential for good handling:

-Ball bearings (dry work much better)

-Ball diff (smoothens out drivers input and has LSD effect)

-CF H-Plates (the stock ones break easily, and don’t scrimp, buy kyosho or GPM, some other brands use cheaper carbonfibre which doesnt always return to its original shape)

-Tyres…whatever is needed for the surface, smoothe concrete and 40 degree compound go together well, on carpet/ashphalt (smooth) 30 degree or lower works good.
You may need to get wider rims to use wider tyres, depending what RTR set you get.

-NiMH batteries, i suggest Energizer (make sure they say made in japan) or SANYO, jaycar cells are good too, but when using high power motors, the Japanese cells shine.

-Faster motors/ESC/battery modifications…well, the sky is the limit whn it comes to power in a mini Z, i myself built one that topped out at 84km/h on the Tamiya Speed Checker…one potent machine that was…when it was running right…

[TOYO]

From an efficiency point of view there are at least 4 aspects of a Mini-Z that I would dearly love to reconfigure, one is so irritating that I throw my hands up in disbelief,(send lot’s of money and I will give answers)Anyway I do believe this forum is about micro’s and so….managed some laps on circuit, flywheel and flaired guards showed their worth, car no longer jack-knifes if you power off while turning, and if you side-swipe wall car merely glides along so you can steer away without fuss. After double charge(naughty!)new Subaru completed 80 laps at average speed of 4.1 km/h and covered 728 metres!
So tantalizingly close is the magic 1000 metres that this is what I shall aim for.Have managed to get weight down from prototypes 33 grams to 27.5,tran’s housing with bearings but no diff’ is 2.5 grams.Yes,I know that another battery taped to roof will ensure victory but that doesn’t prove (oh no,it’s that word again)efficiency of design.Will do serious attempt soon.

[jamiekulhanek]

Remember these motors are about 25-30% efficient at best….

Try graphite lube on the gears…could help.

And the battery is replaceable with a 200mah NiMH cell the same size as the original.

A single charge only charges the battery up to 10%

[betty.k]

if he’s using the enertec batteries, they’re dual 1/4 aaa 70mah nimhs. there is room in the chassis for 2 x 1/3 aaa. with the stock batteries i would charge it on the controller 3 – 5 times:8ball:

[TOYO]

Crickey! you guy’s ain’t just good lookin’..smart too! Removed batteries and tested cells individually. Tis’ true that a single charge isn’t enough however they did come up to 60%-70% and the second charge 90%-100% at 1.37 volts apiece. I did this three times with approximately the same result. A third charge was tried but no measurable difference was found, they did however become warm. Last year charged a “c” cell made in France, but only came up to 75% so repeated charge, after a while could hear hissing sound then several loud pop’s, negative end cap had bubbled out and battery was red hot, been a bit shakey about this repeated charge business ever since.

[merc-blue]

toyo if u really want to get some kick and keep the efficency up how about a single cell lipoly it should put aout about 3.6v and have around 1000mah compared to 2.4v 200mah (if u used the biggest capacity vells around) also less weight which again will increase run time

[jamiekulhanek]

Quote:

Crickey! you guy’s ain’t just good lookin’..smart too! Removed batteries and tested cells individually. Tis’ true that a single charge isn’t enough however they did come up to 60%-70% and the second charge 90%-100% at 1.37 volts apiece. I did this three times with approximately the same result. A third charge was tried but no measurable difference was found, they did however become warm. Last year charged a “c” cell made in France, but only came up to 75% so repeated charge, after a while could hear hissing sound then several loud pop’s, negative end cap had bubbled out and battery was red hot, been a bit shakey about this repeated charge business ever since.

Don’t go by the voltage, a battery charge cycle is not linear, a single charge only charges the cell at around 10%.

For best results, install a DIN switch, and charge the battery using a delta peak charger.

I found that the “load” of the PCB on the cell caused the charger to freak out and cancel charging, hence the need for a switch.

[TOYO]

Excellent information troops,(obviously yet another goddamn thing to learn on top of “end of year” accounts which I’m up to my neck in) will ditch original charger and rewire car to flashy looking computer controlled charger,however will only resort to different batteries if unable to crack 1000 metres.

[merc-blue]

lol with a lipoly you will make 2000 i recon

[jamiekulhanek]

You will find the runtime goes sky high with a delta peak charger
expect more than 20 minutes continuous throttle from the stock tomy (aka sanyo cadnica) 50mAh cell.

[TOYO]

SUCCESS! Had to put project aside for a few days, however first serious attempts made today, one lap travelled centrally around circuit is 9.1metres, so 110 laps is just over 1000 metres,a calculator was rewired from “=” button to a very light mechanical switch which is activated by the passing cars antenna.A stop watch operated by daughter.Eight attempts were made with a double charge only, 100 laps-12.01 min,106-12.47min,109-13.48min and at last 111-14min@ 4.32km/h but then..118-13.58min,140-16.39min@4.59km/h,130-15.27min and 130-14.49min@4.79km/h!!During the outstanding 140 the Subaru spunout on lap 82 but reverse was only a crawl?? anyway straightened up and completed the rest, by days end reverse was just a memory, one set of brushes had worn out and broken off only just contacting in forward, which is understandable as the motor had by now covered an amazing 16km over 3 different testing periods!Three 10 lap sprints produced average speeds of 5.2-5.45 and 5.55 km/h, boost was never engaged throughout,5 single charge runs were also completed.Steering remained totally consistant throughout the days total distance of 12km.Calculated that each steering command costs 2metres! so perfect timing and duration of the command was essential. Have couple of images for gallery.Anyway have achieved the goals and will put micro racers away for time being and attempt similar endurance test with TYCO Crossfire,sure been lotsa’ fun.

[TallduDe]

amazing result!

basically over a 0ne kilometer with a bit, i know this could be asking much but how about a video of the car driving to see it in action?

well done agian 😀

[TOYO]

Thank you, Talldude, hmmmm.. a video, I could do that..and send to Ausmicro?..leave it with me for a while.

[TOYO]

As much as I try the TYCO’s gentle 13km/h and total reliability doesn’t capture the imagination like the micro’s and this question of just how fast can one go was too much temptation.Hmmmm… so it was to be expected that yet another Enertec was sliced up and reconfigured. This time a jig was made first and the chassis digitaly machined/drilled whilst held in place to ensure absolute alignment between front and rear axle’s. Although identical to the endurance racer great care was taken to lighten each part and lower the ride height by 1.5mm, a different tooth profile for the half shafts has produced a diff’ as smooth as silk, stainless steel kingpins(non-magnetic) to eliminate magnetic conflict, but the big difference is the reduction from 11-1 to 8-1 still using the 160 dp gear profile which appears to be quite suited to these cars. After getting all the rewiring right first time(!)it was applied to the race track…GADZOOKS..although somewhat slow off the mark it accelerated at a rate that I couldn’t keep up with, back to the calculator…no load wheel speed of the endurance car is 2600/3100 giving an on road speed of 7.2 km/h measured over a 2 metre section( the prototypes have similar no load speeds but only crack 6.5km/h due to higher weight and low efficency g/box)however this latest device produced 4200/5000!! giving theoretical speeds of 11.36/13.37 but don’t panic, measured over 2 metres it pulled 10.33 km/h with the motor churning out 40000 rpm all this on a single charge!! Phew..this is all a bit scarey for me, the motor used is not a green end cap (as fitted to all the other cars)and which appear to be a bit of a plonker, but has a yellow end and gets quite warm as the others are as cool as cucumbers. I may be forced to rid myself of this screamer and fit a docile greeny as the car is almost uncontrolable and goes flat in 4 minutes, to be fair though this was only it’s first run and it may need some fine honing.

[jamiekulhanek]

Well, it looks like you need to look into the electronics efficiency…

A FET mod will help here, but there will be more current drain due to lower resistance…

A Bit Char-G is capable of 30km/h….

One thing, i don’t like the idea of a gear diff, don’t get me wrong, i think your skills are fantastic but gear diffs are sh1t and a waste of time…

Ball diffs are far far far far better… perhaps you could make one??

[TOYO]

TTTThirty kilometre’s per hourrrr! Jesus wept!When-were-how-by whom? I am but a mere amateur and shall now take poison, but before that, this ball differential that is spoken of in hushed tones..I have built compound turbine engines, epicyclic steering gear for tanks, constant mesh g/boxes and nipple clamps but haven’t yet come across ball differentials, roller & cam “differentials” that don’t allow reverse(gas cars) I am familiar with. I work on a theory that if it isn’t used in full size practice then it’s not worth miniaturising, however in my business it always pays to seek out the unusual and these devices I would like to know about.

[jamiekulhanek]

Most decent R/C cars use a ball diff….period!

[TOYO]

Oh.. so thats how they work, there can be no doubt that backlash would be almost eliminated, axial thrust during a corner would be evenly distributed, very cost effective to produce and highly suited to this size car, but what about loading on the balls during a corner?, they are rotating in one direction and the thrust of the drive gear is at 90 degrees, they also need static preload to keep them all in contact and reduce slippage. I guess one could be made but the geared ones I am using are only 4.4mm dia as there is no more room, probably be done with 1mm dia balls, I can get stainless balls that small-but not sure about hard ones…hmmmm not sure the benefits are worth it, gears don’t slip, no peload, can be physically smaller, less parts, lighter,no maintenance, limited slip ability by thicker lubrication and I guess in my case-having a machine that’s sole purpose in life is to produce small gears makes it easy to lean in their direction. Anyway,a few pics of new micro racer have been uploaded.

[betty.k]

:shock::dead::p:8ball:

[TallduDe]

its fricken alsome!

but if you want more speed get the fett mod done. i thionk u should have no probs doing that to say the least.

[TOYO]

Crikey! thanks for putting the pic’s up Betty(how did you do that?..yet another Goddamn thing to learn)Have managed to squeeze in one more pic. Am trying to get weight down and have knocked out side and rear windows-down to 25.5 grams, 2 less than endurance car. Motor draws so much current that steering was slow to react, have brought toe out down to almost zero and this restored situation. Managed some laps on track after above mods’ and is now controlable but slams into wall pretty hard if you don’t line up corner and miss turning point…ooo nasty! Gee I don’t think I’m up to prawning around with mosfets just yet..sounds a bit scarey to me, I managed to get just under 5 minutes today so will continue weight loss program.

[betty.k]

no sweat man:smiley2: when posting pics in a post, type , but don’t use spaces or capitals like i just did. you can get the url of a pic by right clicking on it and selecting properties. til then here’s another!:8ball:

Edited by – betty.k on 21 October 2004 07:58:01

[TOYO]

Thanks again Betty.K, must say your offroader project has been the most interesting saga about micro’s I’ve ever read/seen, your imagination and determination to see something through to the end is to be commended, even more astounding is the ability to produce a workable product with only basic tools!.. I would however like to give you some advice….beg, borrow or steal a modelmakers lathe/mill combo (stay away from watchmaker machines they are too specialized)
Emco/unimat/are ideal, cheap too,(Ive got one)I have no doubt that with some machinery and your skill, crazy things are gonna’ happen. Enough of all the guff..new car survived 50 laps@ 6.4 min on single charge but only averaged 4.5 km/h due to continually having to power off to avoid serious accident- will get better though.. many new pictures in gallery.

[betty.k]

i’d love some fancy tools! anything would be better than my smokey drill:D

anyways, on with the toyo slide show!:8ball:

[matic]

Hey betty k. that is simply amazing. Don`t tell me that you made this differential by yourself. And what kind of chassis is this? I have never seen anything like that. can you tell a little more about this? Once again AMAZING work….

[betty.k]

hang on, this aint my work, it’s toyo’s. i’m just posting the pics up for all to see.

it’s an enertec chassis, just read all of toyo’s posts for the full run down of this amazing car:8ball:

[leonli17]

I nearly passed out when i look at those pics. Simply astonishing. this is gonna win Bit of the century award!:D:D:8ball:

Good work TOYO.

[z-beam]

drool. that effort is so totally amazing. Ausmicro was known as one of the more technical micro rc sites since the begining, but this piece of work is sensational.

once you have the winning combination toyo, how much do you think a pair of these mighty machines would be worth?

and from all that you have learnt now how much time would it take to reproduce one?

simply amazing!

[rashumble7]

WOOOOOOOOOOOW, i’m at loss for words that is pure genius. I have not seen such ingenious work with bits since the germans, Toyo congrats that is truly amazing. And as z-beam stated, when?

[TOYO]

When I was a wee lad it was always the same,put your toys away and go to school/bed/work, not any more…the machine shop is swamped with micro’s and I don’t have to put them away anymore. But alas troops, as said many times before I’m one of the lucky ones and micro’s just seem to fall into the sphere of my work and have no limitations as to what can be achieved,(just wait a while and the awd should be ready)I have managed to streamline production of cars but don’t expect change from A$500…If it is a must have item remember that they probably aren’t as robust as a Tomy and cannot be modified unless you specify what you want before ordering…..oh and black Subaru reached 10.6 km/h over 3 metres but have lost interest while working on new car.

[jamiekulhanek]

Dude, im serious a FET mod would amaze you, not only does it double the speed, it quds the torque, a single cell FET modded car will pull wheelies easy!

[Admin]

very nice work, toyo:)

[z-beam]

did you make the front suspension springs?

i still would love some custom parts that are made specicicly for a tomy chassis (unmodded).

have you seen professor farnsworths bit ball diff? its an excellent example of simplicity and functionality.

your stuff blows it out of the water tho but its still worth checking out.

[TOYO]

The front springs are made of delrin using a type of thread cutting attachment on the lathe with .75mm pitch,needed something that wouldn’t attract magnet, they are also more supple that metal.Yes Jamie,I have no doubt that modifications to the electrics will produce a rocket ship, many years ago I raced an 860 Ducati and speed was absolute priority, bugger handling and efficency, but I’m an old man now and get no joy from straight line performance, the car must be controlable, reliable and offer near perfect repeatability within a defined environment so it becomes a matter more of skill than good luck.I hope to take them to Japan in near future and possibly hook up with some geeza’s for an assesment of cars/tracks and maybe a shoot-out hence the awd project, just to see if this is a solution to limitations of rwd only.

[merc-blue]

but toyo ur a efficency nut doesnt the low efficency of the cheap elecronics bug u?

[betty.k]

righto. get off toyo’s back!:D all ya’ll!

what you’ve all failed to notice is that he’s using enertec cars. the pcb is completely different to that of a bcg or zz. it uses a completely different ic (“pt” type) and has a strange 5 fet h bridge. yes that’s right, it already has fets!

check dis (my first post too!):
http://www.ausmicro.com/topic.asp?TOPIC_ID=1378&FORUM_ID=9&CAT_ID=2&Topic_Title=enertec+micro+racers&Forum_Title=Bit+CharG+and+Micro+Radio+Controlled+%2D+Technical

so while it’s possible to upgrade the fets on an enertec pcb, it’s “a pain in the arse!”

if you guys want him to have a fetted bcg pcb to play with, send him one!:smiley2::8ball:

Edited by – betty.k on 02 November 2004 16:53:08

[TOYO]

Very good point Merc-blue, but I am just a simple nuts and bolts man and some basic tests have shown that 2.4 volts go in and near enough 2.4 volts powers the motors which I use (they are not recommended for voltages higher than 2.6v), the endurance car is on it’s third motor now so obviously pcb mods aren’t going to increase motor life.So these are the limitations that I work within, another factor is that I have had no pcb failures in more than 2 years ( I have several cnc machines that like to cause days of misery trying to find which capacitor on the smb has blown).Betty is correct,you talented bunch perform miracle’s with pcb’s that I just don’t understand and I have the automotive systems but the results will be the same…a fast micro that is uncontrolable with premature motor failure. If speed is king then ultimately you will end up with a slot car, as interesting as that sport is it can, in no way compare with the brains and talent required in r/c.

[TOYO]

Whilst trying to nut out seemingly impossible steering problems with the awd project, I came across an “X-TRECK-2” reading the info’on the box seemed to good to be true…alas it was more orrible’ than anything you could imagine, you can understand why they need a track to run on, but why so sophisticated the transmitter ???..curious thing the “X-TRECK”.
But arf’a mo’-push aside the awd and nut this one out…much cad work followed but in the back of my mind (just like the Roman Philosopher SENICA told us)I was prepared for failure. But it didn’t and it does’.Jesus wept how good can micro racing get when you have PROGRESSIVE THOTTLE and VARIABLE STEERING that allows you to steer around any obstacle course you desire at a speed of 1km/h or scare yourself stupid on a race track with a top whack of 9 km/h, not only that, drive in reverse with almost equal control and have the same turning commands (in forward motion left turn is left in reverse left turn is still left!!!) From a standing start give it full power and watch those front wheels spin like crazy but don’t panic for you have complete steering control and 9 minutes of absolute bliss ahead of you.
I guess you want to know it works, simple really, image a normal front wheel drive/front wheel steered chassis but have a separate variable speed motor driving each wheel…and thats all there is to it! Under a hideous PT Chrysler shell I managed to squeeze in twin motors and 8 to 1 crown wheel type gearboxes, the shaft of the alloy crown wheel drives a cv joint with a ball dia of 1.6 mm onto a stub axle of the front wheels, the gearboxes are adjustable from 0 degrees to 7 degrees trail and the usual toe in/out eccentrics on the steering link, a centering spring is fitted with an alignment cam as well.This unit is suspended from the top with a PVC stip that also allows changes in wheel base length. A centre section carries the shell mounts/pcb/batteries/front suspension strip and rear suspension mounts. The rear wheels are mounted on trailing arms either side of the batteries and are sprung by a .4mm piano wire sring. All up weight is a crazy low 26 grams.What I thought would be an insurmountable problem related to the fact that one motor spins forward whilst the other spins in reverse and no two motors have the same characteristics in this situation, however the good folk at xtreck fitted a power balance adjustment to the transmitter and so no problem exists, it also boasts 3 power curve settings, GADZOOKS what more can these things do?

[TOYO]

Whoops ,in my excitement I forgot to mention some new pics of this little screamer in the gallery.

[TallduDe]

farrrrrrr out man!

looks the business can i see some pics on how it is 4wd like how does the rear wheels get power? the batts seem to be in the way?

would like to see a vid of it in action hint hint :smiley2:

[TOYO]

Whoa’ hold the bus there buddy, this ain’t no 4wd(yet) purely front wheel drive only, this little gem will need an epicyclic drive between the front crown wheels which will give 100% drive to the rear axle only when both motors are at the same speed, as one slows down so does’ the epicyclic output, this will cause the steering to over react rapidly compared to the amount of turn that was initially signalled from the controller, however a roller clutch in the drive would overcome this but give no drive to rear axle in reverse. Phew! don’t worry…Ive already taken this chassis to extremes on the cad.

[TallduDe]

ahhhhhhhhhhhhh my bad :blush:

good work non the less

[betty.k]

holy crappers!! 😯 he’s done it again!!:p

the following pics belong to and are the work of TOYO:8ball:

[merc-blue]

toyo.. i will soon have a full proportional (using PROPER eletrics) BCG.. i was just wondering if i could send it to ya and u could put some bearings in it and see how ya like playing 😉

[z-beam]

drool! your a smart bastard toyo! i want to drive that rig of yours so bad man! so when can we expect these on the shelves:smiley2:

[TOYO]

Much appreciated Betty, GOD will surely turn you into a sunbeam, anyways’ have finished some serious testing on the race track…..BRILLIANT, there appears to be nothing this chassis can’t be applied to,it took some practice getting used to being able to reduce the power coming into a corner to avoid a broadside (too much weight over rear wheels)and using little or large amounts of steering when required, half of the track was in the rain but it made no difference to the PT as even in a slight four wheel drift and the front tyres breaking traction steering was as precise as in the dry. I fitted an adjustable turning circle limiter to the steering link and modded the transmitter to stop reverse motion being activated on what ever wheel is on the inside of the circle and this immediately gave the car high speed predictability, it did however spoil it’s spectacular ability to be driven accurately in reverse and curtailed it’s prowess with snail pace obstacle courses on the kitchen table…damn,damn,damn. It is however blighted with poor endurance, on a double charge only 60 laps were completed, but considering what the circuitry must be doing to allow such wide variations of performance it is, I feel an acceptable limitation. Have said that, I will consider building another with both motors turning in the same direction. How does’ it compare? The Enertecs are serious little cars with oustanding endurance/speed and are highly suited to a long slow curve circuit, what the Xtreck lacks is far outweighed by its’ ability to tackle anything, fast, slow, tight, broad, wet or dry and importantly, the fun factor.
Build em’? narrr…same old story, too expensive too fragile too GOD damn fussy about their environment….get a mini-z.
Can’t wait to see a proportional BCG!!! but as for modding, will it require a complete rework? I’m certainly interested.

[merc-blue]

nah im not as fussy as you on drivetrain i just wanna get bearings on the rear axel and front wheels (tyred once an was a disaster)

[TOYO]

Ah yes,.. as the sun sets on yet another day of track side entertainment, the PT cools off and I endevour to enlighten all about the project thus far…in order to improve endurance the Tomy motors(green end)were replaced with the low resistance but short lived xtrek original (unsupported comutator)type and much removal of excess weight from what ever I could(only 1 gram.. down to 25). A severe vibration was evident with the starboard gearbox and the crown wheel inner support shaft was found to be eccentric so a complete new crown wheel was more carefully made, however some vibration is still there and probably caused by the 6 tooth motor pinion, it must have had some effect though,as the power balance adjustment is just left of neutral. The pcb was moved forward 1.5 mm and more clearance made around the motor wiring to reduce binding of the front suspension strip. I am begining to have some doubt about the trailing arms torsional strength as high speed cornering is not ideal, even though c of g is as low as possible the rear tyres lose grip easily and me thinks the loading on the outside tyre is high enough to bend the arm until a point is reached that it flicks back causing the tyre to break away….hmmmm. New tyres made from blue “absorbathane” were fitted, (closest thing to gindable glue I’ve found) batteries charged and track dusted down. I decided to go for only single charge attempts in view of motor issues’ and the turning circle was set for minimum move ment, the new tyres made an impact and average speed steadily increased from 3.4km/h to 4.6km/h with 43-47-49-48-48 laps recorded (didn’t break the magic 50..doh!) speed is well down on the Enertecs 5-5.5km/h but the Chrysler rarely made contact with the wall. The minimum speed jumped from 1km/h to 1.9km/h and top speed went up to 9.6km/h measured over a 2 metre section with 1.5 metre run up, wheel dia is 13.5mm and 4400 rpm on full power with the motors churning over 35000rpm, there was less than 200 rpm difference between the wheel speeds on full power. Strangely, I prefer to drive the car very slowly around the course with a goal of not making contact and managed 15 laps at an average of 3.2 km/h. Where to now with the outstanding xtrek?

[z-beam]

i swear if there was a 1/64th scale forula 1 we have the top contender right here!

[Author]

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