RC India

I wasn't sure about taking part in the '14 sweepstakes because none of my ongoing projects fit into the regulations.
Anyway, I decided to rebuild my long time darling, the G3, a three wheeled, direct drive RC car.
I might have started out a bit late, I think. Hopefully, I can finish it in time.

The car is fully scratch built, trying to limit off-the-shelf parts as much as possible.
Currently, except the the wheels, motor, shocks, hubs, and electronics, everything else is fabricated.

Using a reworked DT750 outrunner with a 1/10 65mm wheel directly bolted on to it, plenty of torque and fast enough to get nasty.
Planning to use a 3S 1Ah LiPo to keep the weight down.
Overall weight is expected to be around 700-800g.

Base plate.
1.5mm aluminium, 250mm length, 93g.

Swing arm.

1.5mm Aluminium, 63mm length, 17g.

 ;D

I tried using some 3/4" L-angles to mount the rear swing arm. Unfortunately, the aluminium was too flimsy to hold it firmly.

Today, bent 1mm aluminium into a couple of L-angles and it's all pretty stiff now.

Waiting on a couple of axles and hub carriers to be turned and milled out for the front end, hopefully, I get them by the weekend.  ;D

All the best sir :thumbsup:

Wonderful.
Motor inside wheel is great!

Excellent work. {:)}  If you can fabricate the body, you could have the world's first RC Auto-rickshaw ;D

Ashim.

Cool! {:)}

Even though the DT750 motors provide a lot of torque, I think it'll be safer to use some gearing (say 1.5:1) with a belt drive. That way the motors won't get overloaded.

Are you going to use ESCs with reversing capability?

Here's something fun I made a while ago to test the DT750 motors...

www.youtube.com/watch?feature=player_embedded&v=YSnDbtCshNU (http://)

Yash & Iyer sir, thanks! ;D

Ashimda, I hope I can build the body too, but if I can't, what's lost in looks will be made up for in speed. ;)
If do manage to build the body, it would look the RC auto rickshaw in the screenshot.

Swapnil, yes, the motor does get warm slightly because its not cooled.
Outrunners get warm/hot/fiery if not cooled properly, so even if I gear it down, I suspect, it will still be drawing almost the same amount power effectively, but at different torque/RPM output.
But honestly, I wouldn't want to gear it down because I will be losing RPM over torque that's not required. :D

Work progressing very slowly due to my exams. :(

Finished the front shock assembly, independent push-rod style suspension.

Tomorrow, going to complete fabrication on the swing arm and hub carriers, still waiting on the front axles from lathe work.

Really nice concept trike lol of u like callin it that.
Keep up the amazing work after ur exams on this project

Few suggestions,
1. Rc cars generally use in-runner, brushed or brushless to cope up with the torque required for the wheels. Out runners r mostly used on light planes (250-1200gms thrust), reason being air cooled, little torque high rpm just to drive one TINY propeller( few gms). This leads to a design issue since you chose a direct drive, no gears. It's good for low to avg speeds for this weight, but not bashing n speed runs. You can check the limits, but be very careful
2. Use plastic bushings/shims instead or metal washers on moving rocker and shock arm joints. They can be lubricated for quick response from the vehicle. Various ball-pen, gel pen used refills can be sliced to make them
3. Use tread-lock on moving nuts if you can get that, or a glue gun or rc-cement should work. Just some friendly suggestions from another design fanatic

Great job on the build. I love the rocker arms.

Those shocks look familiar. Do you have a buggy?

RumblePirate, Thanks! Trike yeah, but I call it the G3. ;D
Sadly, can't wait till exams end, sweepstakes submissions end by the 10th.
I was cynical about the motor too, at first, but then I can do 15 seconds+ burnouts with the motor barely getting warm on a 3S and it doesn't even go over 20A with the motor rated to 30A peak.
I agree on the air cooling part, I'm yet to test the run time limits.
Shocks have nice ball links in them, I'll try shoving servo mount bushing on to the rockers.
I skipped thread locker and used lock nuts instead, so all good on that.  :thumbsup:

iamahuman, Thanks!
I had got the shocks from RCB long ago, they're offroad, yes.
 

Finished suspension tower today.
I scratched my head over this a lot and then I found some rectangular frame in my junk, voila! Perfect.
Set it back slightly, from the original position because the shock push rod, steering tie rod and suspension arms were colliding.
Steering servo will be mounted up front due to clearance issues.

Tomorrow, fabricating suspension arms and hopefully, shock rods too.

This is shaping up to be my favorite build thread on RCI. ;D Can't wait to see this finished :P

This is where I started with the trike config 7 years ago back in 2008.

Front end from a broken toy car, I wasn't smart enough to build one back then.
motor from a CD drive
rear swing arm from a hard disk. The most hi-tech piece in there, dial ball bearing!
I had literally ripped the battery off my Tata Indicom landline, it was running on DC, no one found out. :giggle:
Radio, 27MHz came from a toy car.
Antenna from some China phone.

Tried this suspension setup last night, it's heavy, very rough and crooked. Not pleasing. Scrapped.

Today, used some off-the-shelf buggy swing arms that I had got from RC Bazaar.

Reason being, it's far lighter than my aluminium setup and simpler at the moment.

Push rods for shocks have been setup and everything is working smooth.

The hub carriers I made previously were a bit large to accommodate a body shell (If I build one), so making smaller ones.

Front axles fabrication, hub carriers, steering setup and body work is all that is pending as of now.

 ;D

"Tried this suspension setup last night, it's heavy, very rough and crooked. Not pleasing. Scrapped."
Who says?
Homemade one was looking just fine!

Iyer sir, It looks nice, but the suspension arms were shaking a lot, undesirably, constraining those from moving sideways is unwanted complication and unreliable too.
Besides, the whole setup was 120g; Vs. the ~40g current one.
So I decided to use the plastic ones without wasting much time over it.

I use hand tools except an electric drill, so it's a little hard to fabricate high tolerance parts. Wish I had a Dremel.  

Ok for the sweepstakes.
But this is only the bottom half of the suspension.
Where's the top half, king posts etc?
And the issue of how much the steering arms be raked to ensure that the turning radius of the inner wheel is less than that of the outer wheet etc...

I think your metal work was good and that you should continue.
When you have the time,
Separate the motor issues and chassis issues.
Think about the chassis parts in detail, draw them up, and get them laser cut in a suitable material.
How do you think they build Morgans?
You should build at least one complete trike by hand (incl shocks. Or forget shocks. Why do you need shocks? Replace with just springs and forget about damping)

I don't know you, but as my vote of confidence, you can borrow my Dremel...

The top half is almost done, I didn't install it because I hadnt figured out the steering servo placement and there's not much space around there.

I have to make a new smaller hub carriers.

I wanted to build most of it myself, pretty much everything I can, but I want to complete it in time. Surely, I'll build a all DIY front end after a while.
I will try laser next time. :thumbsup:

I like to push my boundries every time I build something, so I usually try new things, this is my first pushrod suspension build.

Thanks for the Dremel offer, very kind of you, sir. I'll get one as soon as I am not broke anymore. :giggle:

Almost finished setting up steering mechanism, have to link up a couple more rods and it's done.

Upper suspension arm still pending, figured out the setup, building it tomorrow.
 

Started body work today, 30% done.

Will need some trimming in the front end, forgot the upper suspension arm clearance.  :banghead:

You would be better off using a lower gauge rod for the servo linkage. A triangular bend in the linkage will be another way to minimize servo damage.

Trishit, I'm using bicycle spokes to link up the steering. Works fine for me, I've ordered a servo saver which I will be using.
 

Finally, the car is done and is running, a little too responsive, going to setup radio properly tomorrow.

Steering links must be tweaked a bit.

Too quick for my on 3S, will be running on 2S for sometime.

Body work, paint and lights still pending, it will be completed tomorrow and hopefully, I can post a video.

 :thumbsup:

...

That's one sweet ride :D

Hatsoff to you dude!
Really great work. It is one of a few cases where you see your design come to life

Trishit, it sure is sweet. ;D

Prateek, Thanks. I loved this build.

Awesome car ... :D ;D
:hatsoff: for your tremendous effort

Topalle, Thanks! ;D

Added some paint to the body shell today, ran out of silver paint, so only that's pending.

Car trimmed and radio is setup.

Going to make a video tomorrow.

Added some skirt lights to give it a facelift in the dark. :D

Wow!
What a 'Junk Artist'
Send a photo to ][
(Dilip Chabria. That's what his DC logo looks like)

Edit: Clear windscreen in front please.

I ran out of paint, so couldn't finish up the front end. Going to complete it tomorrow.

I'll just build a full scale version myself someday, Iyer sir. ;D

fabulous efforts .....is the car running ?? you have put wheel directly to motor.... initial torque will be less but later you will run out of space to see high speed!!!....

do post a video of the run.

Great build.

The similarities between this( apart from 3 wheels versus 4 :giggle:) and old pan cars are striking.

rastsaurabh, Thanks. Yes, the car is running.
It feels like there is a lot of torque on the start or maybe lack of traction since it's only one wheel at the rear, either way, I'm running on 50% throttle exponential to keep the wheel spins down.
It's definitely going to have a lot of high end speed on a 3S, not sure if it's safe for me to run it that fast without much driving experience.
Video coming up soon, haven't found a good place to run yet.


iamahuman, Thanks. I love pan cars! They can be such simplistic, yet notorious speedsters. ;D

You outdid yourself this time Anjan! Just don't ruin this beautiful ride with decals or graphics ;D

Amazing work Anjan ! Outstanding Effort
Sharing these pictures on www.Facebook.com/PunjabRcRacingClub (http://) so that Engineering Students also get motivated to Make these kind of unique Things !

Please Tag yourself on the FB Page.

Regards,
Harkirat

Trishit, probably, I thought I'd save Arduino traction control for another thread on another day. ;D
I have to go give an exam tomorrow, I'll draw the decals there. xD

Harkirat, thanks a lot man! :)

Traction Control = No fun. :P

Building a traction control system for an RC car is the fun part! ;D

Brilliant work Anjan, very impressed. {:)}

Ashim.

Anjan what a build

Thanks, Ashim and Nitesh. :)

Painted the car green.

Finally, I found a school ground to run the car and I realized it's the worn out wheels that are making it run clumsy, handling is ok, definitely needs new wheels.

Crashed into the side of a wall a couple of times, upset the right camber a bit, but still good to go.

I love how fast it is, but anything above 40% throttle need pro driving skills, very fast.

Sharing the video tomorrow. :thumbsup:

Thanks to my friend Madan Kumar for the picture. ;D

 The exposed wheels look cool but they are a bane.
You may solder a piece of thick metal wire in front of the car to protect the wheels..I ruined two cars running them without the guard.

Yeah, I'm planning to add a piece of aluminium and make some foam bumper until I learn to drive properly.

Great one Anjan . This looks awesome . Waiting for the video  :thumbsup:

Fantastic job Anjan :-) i know how tough is that sheet metal job, you need a right skill and right tool. really great job.

Dhruva and Nithinraj, Thanks! ;D

Video finally!

70% Steering EPA
75% Steering D/R
20% Throttle Exponential

Sorry for the slow speeds, I didn't want to crash the car trying a fast run.
Running at less than 20% throttle in the whole video.

https://www.youtube.com/watch?v=f4i_EASJL5w (https://www.youtube.com/watch?v=f4i_EASJL5w)

I managed to do a 40-45kmph run on a road, hit the lip of a manhole and the car flew 3m and landed upside down, no damage, just glad I didn't have the body shell on.

I will post another video with the body.

@anjanbabu
Somewhere along the line, we all forgot the need for brakes?
Run it in reverse and compare the handling.
Your driver can't see anything thru the black windscreen anyway...
Perhaps you can quickly make a racing autorick body ;D

Iyer sir, the car was about 50m away and I couldn't see properly, gave it a good right steer and it went over the manhole and so on.

It decelerates pretty quickly, doesn't really need brakes.

Running it in reverse is so weird, doesn't turn well, a lot of under steer.

I can count at least 10 autorickshaws every 100m in Bangalore, not another one. ;D

No.
The real point is
Shoiuld autos run the other way?
Which one is more stable?

You can tell the rear loses traction easily at speed. Had the CG been higher, you could've recreated TG's reliant robin stunt. ;D

Iyer sir, Autos should run the way they should, but I didn't mean to build one. :D

Autos have front wheel steering, but when i reverse config my car, steering happens in the rear end. So understeer.

Either way, I think this is more stable than auto config because, autos tend to tip over on two wheels while cornering at fast speeds, but my car has better grip on the front end and no chance for tipping since it's only one wheel at the back and it has to be going must faster than an auto config to roll over while cornering. I could be wrong, but from what I've seen and learnt, a single front wheel vehicle needs tilting of the body to keep its balance on high speed cornering. I guess the physics is duly understandable without geekish research papers. ;D

Gandhar, I'm running worn out slicks on concrete. I did some high speeds runs and it spins out dangerousy. it takes off like a dragster on tiles with clean tyre surface though.
I think it will do better with some treaded tyres, planning to order some wide buggy wheels. Any suggestions? A link will help better!

Put some weight over the back wheel. IMO treaded tires will not make much of a difference. If you switch over to a softer compound, it may work. But softer tires wear out quickly.. Anyways people use slick tires on dry tarmac as they provide better traction over treads :P

Play with the weight distribution. In my experience that is the easiest way to set up handling on these diy rc cars..

Trishit, slicks lose traction when dust and dirt gets on the tyre surface. I'm using Sweep Racing's soft slicks, is just used up too much, I can see the fabric inside now.
I tried to shift the weight rearwards as much as possible, not helping there. Even shock is set to minimum tension.

You can try foam tires. I think wheel sizes will be the same as standard 1:10 tc wheels. As a 'band aid fix', spray a little wd40 on the tires. They soften up after a while. If you find the time, you can make some tire warmers. ;D

Foam tires will grip really well but will get beat up on rough surfaces and they'll start losing matter in chunks.

As for buggy tires, race treads will wear out very quickly. I think they're best avoided.

I'll PM you the link.

I think I'll just get some treaded touring car wheels and try them on, if I can do high speeds straight runs and 40kmph circuit runs, its good enough.

I used to clean these slicks with brake cleaning fluid, but dirt gets picked up and it loses traction soon.

Anjan i must you have done a fantastic job on this and sorry i couldn't comment on your build till now but this is awesome congo :)

Regards
yash :hatsoff:

Thanks, Yash! And no problem.  :thumbsup:

Great work Anjan
Came out really well.

Thanks, Manoj. :)

Video with the body shell on!

I dared to push it a bit faster than in the previous at the cost of running it into a wall later on that evening. ;D

www.youtube.com/watch?v=hnJMHWQKc20&feature=youtu.be (http://)

Cool ;D Go to a bigger rear wheel and fix your steering. One of front wheel looks to be a little off..

Fantastic build Anjan!

@anjanbabu,
If Lamborgini ever build a trike, this is what it will look like!
Just saw your video.
I suspect she can go MUCH faster.
But you will need far more space, like a tennis hardcourt with the net removed.

BTW, it does oversteer with power, ie, tail drifts out and nose turns in.
Perhaps you can consider trying high expo (70%?) on steering...

(Had made one like this with a Cox .049 and 6x3 prop about 25 years ago. With my son's He Man as driver, as reminded by ashok baijal in one of his posts)

Trishit, it's got enough torque to direct drive a 1/8th wheel, but would look out of proportion on this car.  I'm planning to build a 1/8th direct drive or 1/5th with CVT.

HPV, thanks!

Iyer sir, everyone finds the front end very Lambo-ish. :D
Yes, can go much faster, I didn't go over 20-30% throttle in the video.
I will try the steering exponenital.
I tried gluing 5mm strips of bicycle tube horizontal to the tyre surface like a sand buggy wheel, only much flat; the oversteering disappeared until the strips started ripping off one by one.
The fix was not really practical, of course. Just proved that the rear wheel needed more grip than I had anticipated, even with the CG as rearward as possible.

Heat a piece of wire and melt grooves onto the tyre you already have on the car. See if that helps..

Its rubber tyre, i tried a 100W solder iron, couldn't put a scratch on it.

Now, what's Watt to do with temperature? ;D Heat a piece of wire. Best bet is to bend the wire in the shape of the tyre and then heat it and apply (almost red hot).

More watts = more consistent heat.

I heated a cycle spoke and tried branding the tyre, still no effect.
I'm about ready to give up on this and make my own tyres with some bicycle tube for now.

Did you try WD40? Let the tyres soak in it for a while. The solvents do wonders to soften the rubber up.

I dont have WD40, ATM. I used brake cleaning fluid, it does help but loses traction after just 10m or so. I can feel the grip when it takes off and then no more.

I think its all the dirt and dust that sticks on the wheel is the problem. Planning to switch to some wider treaded wheels.

You must be using quite a dusty road. :D

Did you get any info on 1:10 buggy premounts? I couldn't find any suited to on-road use.

Yeah.

I saw a few buggy rear wheels, with dotted surface, no tread pattern. Didn't look like it would last even an hour on tarmac.

 AnjanBabu :goodjob:

Thanks, Wingmanbunty!

Old body shell was made of 2mm sunboard, it was a bit flimsy and fragile, so decided to build another one with some stiffer 3mm sunboard.

The basic design is same as previous, just giving it a sinister look on the face with a few lights, some other flashy bits here and there and probably a multi-tone paint job.  ;D

Take it to a CNC shop n tell them U need turnings onto these tyres. it can be done in a fine way, but be careful n dont the get the whole tyre damaged.

miginstruments, I made a tyre myself with some 2mm foam and rubber stripped from a bicycle tube, worked pretty good on rough concrete.


New body painted and glowing with a evil grin on the face! >:D
I can't seem to stop working on this car! Upgrading the motor to a 900kv from 750kv and new wheels too.
Also, working on an Arduino based traction control system while I wait on that HK parcel.

great build some videos of it running would be great

Regards
Chintal
Rcmumbai.com

Looks Like Batman Car

Chintal, I've posted a couple of videos here, check replies #55 and #71.

Miginstruments, I guess. ;D

@AnjanBabu

from the start your project looks very creative.

awesome car,

wingmanbunty  &  desachristopher, Thanks! 8)

Can you please elaborate the technique you used for making the tyres with pics?

Topalle, I don't have any pictures right now, I can redo it and post it up in a couple of days, if you want.  :thumbsup:

Basically, I cut strips of rubber from an obsolete bicycle tube/bladder matching the width of my wheel rim, then layer the strips over the wheel circumference until you achieve the desired diameter. I used FeviBond glue. Wrap it all up tightly in masking tape for a couple of hours and its good to go.
I used a layer of dense 1mm foam in between to give some cushioning on the tyre surface. Lots of grip compared to my last pro soft slick.

It usually doesn't last long since the top layer starts giving away on the joining seem, but mine is surprisingly going well after 13 packs adding up to more than 3 hours of runtime.

Did you try skateboard/ roller skates wheels?
They are heavy though..

Yes, too heavy for this car.

However, I had used a stripped roller blade wheel in a rc drag bike long ago.

If only there had been a single bolt securing the swing arm, the chain could have doubled as the suspension...

^ Definitely a bad idea :P Too loose a chain/belt and it will slip off and too tight and it will either split or cause a horrendous loss of torque.

Arre, just a little joke for Anjan about the rubber band.

Probably my favorite car, it's lasted so much longer than the other ones.
I've updated a few things since the last few posts on here.

Recent updates,
1) Motor reworked for better efficiency, runs for about 15mins on a 3S 1Ah pack.
2) Installed a heli gyro for maintaining stability on high speed runs (Visible in between the front shocks).
3) New wheels.
4) Upgraded the xESC adapter, very tiny now--> http://anjanbabu.wordpress.com/2014/06/20/diy-xesc-adapter-attiny-version/ (http://anjanbabu.wordpress.com/2014/06/20/diy-xesc-adapter-attiny-version/)

Also, Tire shredding burnouts, FPV and a few spectacular crashes!

:hatsoff: anjan, great work!!

How did i miss this yesterday?
So what if DGCA bans flying?
We'll just ask AnjanBabu sir for plans,
As in pic 3 above - with all secret weapons!

Sir, a Morgan in 1/8 scale for next sweepstakes please.

As far as I know, DGCA can ban flying on Civil airspace only, How can few feet of height in our private properties or public places , becomes Civil air spaces?

Sooraj, Thanks! :thumbsup:

Iyer sir, no plans for my trike, it's limited edition. ;)
Although, the Morgan sounds like a good idea for me to start with scale building.

Bumped to revive memories of an impressive build, and for later members who may not have seen this thread before...