Rydh

Hi

After finding some usefull solutions in this forum i like to share my build and perhaps be of some help to the members.

For ten years now i have been driving my fullsize beachbuggy with a turbocharged 2,1liter motor, last summer i had a son så the plan is to build a scale replica of the big buggy for him, since he wont be able to drive it himself the fist couple of years the first version is going to be radiocontrolled.

First some pics of my big buggy:







I found i company i Holland that makes 1/2 scale bodys pretty similar to mine:



Starting to mockup the pieces in my workshop:



The weels are going to be painted silver and black:



The drivetrain: A himodel 200kv motor drives a wormgear with a ratio of 9,5:1, attached to that a homemade planerary differetial.



A local RC shop is going to help med with a siutable speedcontroller when the drive is finniched.

The steering is going to be driven by a Futaba s3306mg servo driving a 4,7:1 gear with the feedbackpot att the secondary axle, that will giv me 110kg/cm and a speed of 0,75s/60degrees. since it's going to be a slow car i think i can live with that

The big buggy has got a turbo att the far rear, the little one must have one also!



A small BW 35 from a oper corsa 1,2l diesel!, just for show!

Some more parts, ball joints for the replica VW front end, a smatt steeringweel, some guages and pipebends för the rollcage and mockup exhaust manifold. I hace a tubebender but i cant do so tigth radius bends!



More to come!, tomorrow i hope to finnish the servo/gear assebly!

//Rydh

Lars from Norway

SÃ¥? Hehey, easy with the swenglish!

This looks very cool, in fact jettekul! Looking forward to follow this build.

wyattroa

a turbo... I like the way you think!

Rydh

It's easy to slip in some Swedish words!

This weekend i built the gearbox for the servo, it's made with the internals if a wheelchair drive motor and has a ratio of 4,7:1. I moved the potetiometer to the outputchaft and so far it works great.

There are some benefits of working as a design engineer at a copany that makes transmission products

I tested to lift 11,2kg 70mm out on the arm and the motor din't break a sweat!, that's about 80kg i servolanguage (why don't just use the torque to specify servostrenght?) in theory it would be a 110kg servo!





[youtube]http://www.youtube.com/watch?v=rsiQ_XvTRhg[/youtube]

It's a bit on the slow side but the car isn't supose to be fast eigther!

//Rydh

TIGER76

Awesome buggy and build m8 [8D] will keep an eye on this thread and what a lucky boy he is !!!

Dirty_Vinylpusher

Hello Rydh, fellow Swede here, although living in Australia.
As soon as I saw your username I figured you were Swedish




I agree with our Norwegian friend, this looks väldigt intressant.



Especially the gear reduction/torque increase gearbox you made for the servo.
I've been thinking about making something similar.

A few people here have experimented with wipermotors and H-bridges to make a 12V high power servo, but what you've done here would work just as well, and be a lot easier.
A bit slower, but from looking at your video it still seems fast enough to me.

Very interesting indeed.






PS. you should start a thread about this on the Swedish RC forum RSB.
I post a bit there as Skrot Nisse.

Lars from Norway

Lol, Skrot Nisse? What a perfect name for you

I like this servo reduction gear too, maybe a bit slower than "usual", but still i think it is enough for a big car like this.

Dirty_Vinylpusher

Yep







Yeah he reduced the servo gearing by almost 5:1 though.
Consider this: if you reduce a 27KG servo by just over 2:1 you'll have 60Kg/cm...

And it will still move pretty fast.



This has definitely got me thinking.



Maybe have TWO servos hooked up to the one reduction box.....






I'm off to the shed.

Lars from Norway

Oh, i thought you lived in the shed I thought about this too, just 2:1 will double the torque, but without loosing too much speed. Worth a thought

Rydh

Thanks for all nice comments!

Actually i wanted a ratio of 2-3:1 but we didn't have any small gears for, I first planned of using at wormgear with 3.67:1 but there is much less play in a ordinary gear so the differens in ratio can easily be compensated by using a longer arm on the s at servogear!

//Rydh

martsrc

Lokking good! Keep us updated.

da mad maori

awesome build!!!
that 1/2 scale body looks cool... great starting point....

electric??? are you sure??? lol

Rydh

Why not? it's not going to be fast, a top speed of 10-15km/h is what i'm aiming for, any faster an i can't put my son in it!

There hasn't been mutch work on the buggy the last days, but i have made a flange and coupling for the motor so now the driveunit is ready for testing out a esc.



Without any load it takes 0,1Nm to turn the motor, so i think that it's not going to be any trouble to start it.

Next step is to make some drawings from the models of the diff that i have been making in solidworks so that I can get some "cnc-help" to machine the diffhousing. The manual millingmachine is out of order så i can't make them myself[]

//Rydh

Dirty_Vinylpusher

Good stuff.

I've started to gather bits and pieces to build a servo like yours for my large scale car.

Rydh

Not mutch progres this week, soon i will have to realy start going!

Bracket för potentiometer:



And for the servo:



Some 3d models of the drivetrain:







The geas i'm using:




//Rydh

Mudgy

Are those gears (bottom picture) from an air motor planetary reduction unit?
They look very much like Atlas Copco ones.

Nice work!![8D]

Rydh

Nope, they are from a precision planetary gearbox for a X-ray machine. But the planetary part was right!

We do a lot of special gearboxes at my job, and there is no disadvantage to be a design engineer at that company

Thanks!

//Rydh

Mudgy

Ahhh...................close, but no cigar!!


Still,



NICE WORK MAN!!

Rydh

My son, house, work and other things has been the priority one the last couple of weeks, but this weekend was able to free up some time, all in all 44parts was machined!


Mockup of the rollcage:



Ordnung müss sein!



I made a new wall behind the weldingcorner and put upp some more lights over the benches



Saving things is a must!



Front wheel and spindle



Modified the rear wheels a bit



The rear hub assebly, 3205bearing, housing and flanges for the wheels



The other side:



The beginning of the front end, a replica of a VW beetle 67-70 balljoint unit.



All the parts so far



Metal knobs that is going to be headlaps!




//Rydh

PejaPolo

Wow i just cant believe how much knowledge you have. Well anyone who can do this if they had the money is just so impressive to me. Hope you get what your lookin for outta this and even the experience should be worth the time and effort. I dont know nearly enough to post my opinions but man doing all this on your own is very inspiring to young guys like me and guys getting into RC.

alvinm

Was that a GWS Slow Stick wing I saw in your garage? I started flying with one and I still have it today on floats for the lake.. I've gotten into bigger planes, but I still favor my electrics..

[youtube]http://www.youtube.com/watch?v=Q9kGCnaCh6Y[/youtube]

Rydh

I would say that it isn't as hard as it perhaps looks, in large parts i just copy designs of real cars ore as in case of the diff a rc-car, the trouble is to find usable parts in the rigth scale. Without the machines that i can use att my job (for free) it wouldn't be easy thow, some parts i cant make myself since i cant run the cnc machines i get help with. In return i sometimes make some designwork for them!

Close, its a pico stick, my first Electric plane. Now i have 10 ore so more planes but my primary interest is the (fullsize) cars!

//Rydh

cummins driver

My Feedback: (31)

That planetary gear setup is basically identical to the one in an electric traxxas stampede, just on a larger scale[8D]

I have to ask though, why not run a 3-5hp briggs and stratton or something? I see you had one on the bottom shelf there

Rydh

The reason i went for elecric drive for now is that its easier to reverse, quiet and it's not supose to be able to go fast since tha plan is for my son is going to ride in it around the house and at all the carshows and dragraces we usually attend.

The motor on the picture is a industrial 80cc two stroke Robin unit from a small eath compacter, perhaps that motor is going on the buggy in a later stage

//Rydh

Rydh

It´s moving forvard, slowly!

A couple of cnc guys at work has helpt me with the housings for the diff





Mounted on the drivegear



"CV" joints, I think that they will work well





Today I´ve been working on the front end:



The frame:



The front end:











I allso bought a couple of small ATV chocks, so now both front en rear will have full working suspention



This week the local RC dealer helped me try out some ESC´s, in the end i bought a MGM compro TMM 16024-3 ESC so that i can run in on both 12 and 24volt. The ESC seemed to work very well with the motor



//Rydh