pedzola

Commonly available tank gearboxes generally operate too fast for scale speed. They can also be noisy, not deliver enough torque, and some models are not compact enough to fit in smaller or oddly shaped tanks.

What is needed is a high torque / low rpm capable gearbox that is quiet, low profile, lightweight, and affordable. Perhaps with some manner of changing gear ratio for different uses.

Given the scratch-building expertise here on the forum, and the proliferation of 3d printers, desktop cnc machines, robotics and hobby electronics parts availability... collectively we should be able to solve this.

Who wants to collaborate to design a better gearbox?

Is it possible to create a design that people can build at home from sourced parts, rather than requiring a traditional manufacturer?

heavyaslead

Sealed gearboxes are very desirable to prevent debris common to tank driving conditions.

I have seen some 1/24 scale sealed gearboxes that are sealed, small form factor (especially for 16th scale), rugged and readily available.

With some metalized upgrade gears, bearings and a hotter motor, should prove quite viable.

tomhugill

I'm not convinced this is a problem that needs sorting. There are after market gearboxes that deliver torque, scale speed and smooth quiet running to varying degrees depending on your budget, from the taigen steel 4:1s which are robust and provide scale speed, going up in price you can get them with bearings making them smoother, there are Mato steel gearboxes with bearing which are similarly priced but arguably more refined. Then at the top of the price range you have the ETO gearboxes, the model spiegl ones and the dklm triple diff ones. On the scratch build side there's a chap called Robert tanzer on the Facebook world rctank group who makes his own with initially with belt drives but now using planetary gears into beefy bevels on the final drive which are amazingly quiet and very strong.

sollie

Robert T's gearboxes
He only builds for private use.
https://www.youtube.com/watch?v=18O-aELZPWk https://www.youtube.com/watch?v=Bl_gZiZlQrQ DKLM gearboxes

https://www.youtube.com/watch?v=8GzNdHIIXBQ https://www.youtube.com/watch?v=QQ0ZUGocO5g ETO
https://www.youtube.com/watch?v=7TWxF2Q4ZuE

Rad_Schuhart

I would like to buy something like the DKLM gearboxes. One motor for throttle and other for steering, but with an affordable price.

Crius

Rad, I think you and I have the same problem. We both have champagne taste and a beer budget.

Rad_Schuhart

Lol, yes and no. It is just I can not justify the prices. For example I dont understand why a pair of cheap pot metal tracks for a Panzer III are more expensive than a steel chain for my motorbike.

I have never tried the DKLM gearboxes, I just wont pay that amount of dough, but I think it is a great design and will solve the problem of a tank never driving straight.

I wish I can find something like that at an affordable price someday.

pedzola

Point taken that there are some viable options out there, so maybe this quest is more about price or availability than a brand new design.

But there are some tanks that cant fit the standard heng long style "4:1" boxes, only "3:1." For those tanks, what other options are available?

Also many options arent available from US sellers, and some of these "boutique" boxes are very specific for the models they work with. For example, I have an eto armor box which is phenomenal, but it is designed for Tamiya tanks and required quite a lot of fitting filing and drilling to get it working in my Torro KV2.

Is there something we can come up with that is the equivalent of 4:1 but fits in any heng long style tank? A design that is low profile and able to made with easily sourced (maybe even re-used) parts?

Crius

I still say they should never have stopped making the brass gearboxes. They worked well and fit in any tank.

TheBennyB

Instead of new gearbox design, a universal gearbox mounting plate would work. Put Tammy gearboxes in a HL/Taigen/Torro/Mato and vice versa if dimensions work. You also have to think about output shafts. Say someone did come up with your "ideal" gearboxes in the dimension and price point but doesn't have the output shaft for your sprockets. Then you have to grab new sprockets which may mean new tracks as well then your back where we are now price wise. I fit tamiya gen 2 gearboxes in my Luchs, if they fit there they'll fit anywhere.

yellowshaker

My Feedback: (1)

www.etoarmor.com
Dead quiet and enough torque to pull the metal tracks apart. No problems with scale speed either. These are the only gearboxes that we need.

maillemaker

The ETO gearboxes seem nice but they seem way to expensive to me for what they are. $265 and you can buy a whole tank.

I think the frame of an ETO-style gearbox could probably be 3D printed.

Can you buy motors and planetary gear boxes and rack and pinion gears from someplace to try and build your own?

Are the silver things at the front of the ETO motors planetary gearboxes?

Steve

TheBennyB

Yea, I can see not wanting to spend $265 on gearboxes for a $200 tank. What would you spend then? $100? That's whats already out there, I suppose with some 3d printed frames you could get the cost down but you'll be looking at less rigidity in the lower hull as the printed frames may flex. Not sure how the printed frames would hold up to the gear shafts with bearing/bushings and possible heat generated. Would a bushing in 3d printed material eventually window out? With the lower profile 3:1's you can always mess with motor and pinion sizes to achieve different speeds/torque as well.

sevoblast

My advice is to take what you have and improve it. With some small skill and/or a lathe or a good drill press you can put bearings in just about, not all but almost all, gears in a Tamiya transmission. The same can be done for anyone else' transmissions. Friction is your enemy, bearings are your friend, not only in the transmissions but in your road wheels and idler wheels. Every little bit helps. For the other manufactures, ditch the plastic or zinc gears and get either high quality brass or real steel gears with either bushings or bearings. For any bearings you need, use either Boca Bearings or Avid Bearings and get the rubber sealed units. Since all our transmissions are made in countries that use metric specifications just go to the charts in Boca or Avid and get the bearings in metric, not only for your transmissions but for your road wheels and idlers.

As for after market motors, you will have to know the rpm parameters you need for your application. Motors with flux rings will generally give you more torque but cut the speed a little. If you are running a light tank and torque is not that important but speed is, you can remove the flux ring and get an additional 5% to 10% rpm increase with the corresponding speed increase. The problem is we use direct DC motors, generally 7.2 volt. These motors are getting not easy to find with the advent of brushless motors and while some aftermarket electronic systems for our tanks will support brushless, Tamiya and most others won't.

maillemaker

I have found this interesting page:

http://www.ebay.com/gds/How-to-Make-...8627181/g.html

Steve

maillemaker

http://www.ebay.com/itm/DC12V-High-T...s/122205608829

maillemaker

Here is a quick something I banged up in CAD that could be printed. And more reinforcing structure could be easily added. Just have to figure out the shafting and gearing and such. Some of the new 3D printing materials are quite strong. I think some of them even have carbon fiber in them.

Steve

sevoblast

Great work, Benny! Have't seem the Type 1's used in a long time. I think I've got some original gears floating around. I'll take a look and if you ever need some let me know. I've also got a couple of the original final drive reinforcements. If you're interested I'll hunt them up.

maillemaker

A couple mods.

pedzola

I think the ETO design is fantastic. Robert would a universal heng long style low profile gearbox be possible at a lower price point? Something you would consider looking into?

I wonder if the aluminum components can be replaced with bent sheet metal (if its good enough for an AK47 receiver...). But I assume the motor gearboxes are the expensive part.

Anyway, I wanted to spur the discussion here because most struggles for new tankers relate to the rediculous toy-like performance out of the box. I spent gobs of money and time trying electronics and gearboxes from all over the world for my first tank. And I know I'm not the only one.

I dont own a Tamiya, as I am sure I lack the glue and painting skills to assemble one, but with the myriad of gearboxes and modifications for those it doesnt seem like Tamiya owners are in a very different boat.

pedzola

Awesome - i knew we had some 3d modeing experts here. So what else is needed to turn this into a functional gearbox? 2 gearmotors, 2 shafts, some screws, and (4?) bearings?

Can shafts be lifted from 3:1 gearboxes? Where to get gearboxes? Possibility for some kind of worm drive instead of planetary gearmotors?

Panther F

"MOST" of the 1/16 gearbox units are mass produced and just dry assembled, leaving it to the consumer to lubricate, break-in and adjust for what they are intended for.

I cringe whenever I watch a TANK YOU TUBE video because at least one pinion gear is too tight (it's usually the mount that is miss-aligned) and is screaming or the whole gearbox sounds like a garbage disposal with a handful of marbles tossed inside.


You can spend more money for a better mouse trap (and there are better ones out there) but a little elbow grease PLUS a few hours can and will silence most of that noise. Setting the radio and selecting better motors also helps with the speed but I'm afraid that's all in the electronics.




Jeff

heavyaslead

Smallest fit I had to do was the FT-17

These are standard HL gearboxes. The motors were changed out from the stock 380 to a smaller format motor for two reasons.

First reason, physically the stock 380 can was too long not allowing the clearance needed to keep the narrow nature of the vehicle. And second, electronically smaller motors would be more efficient. A large powerful motor was not necessary as the smaller motor would be compensated with a custom 2x gear reduction fabricated on the first stage so torque would be maintained. Smaller, more efficient motors will have less current draw thereby eliminating the need for a large stick battery.

Anything smaller than the FT-17 would need to go 1/24 scale!

maillemaker

Unfortunately, I don't know anything about motors, gearboxes, gear ratios, shafts, shaft couplings - nada. Which is part of what you are paying for when you buy someone's gearbox - the engineering knowledge that went into making it.

Does anyone know a source for electric motors and gearboxes and such, preferably with dimensions?


The first time I looked at the ETO box I figured sheet metal would be cheaper than the machined billet frame he's got now.

sevoblast

Tamiyas are much easier to build and use than what you have. Try one and you'll never go back. Sherman is the easiest and the two best bar none are the Tiger 1 and the IS 2 (pronounced 'IssDva'). The instructions are first rate and with a minimum of skill you can do it. You don't have to do a masterpiece with painting on them, a simple one colour will do fine but you will be surprised at how fast your skills will develop. Best prices in USA are AAF Museum in Danville. You can find kits on ebay but often buyer beware is the watch word. Your initial investment is higher than Heng Long and to an extent Taigan but even in the short run you are ahead of the game. First rate electronics out of the box, everything fits first time every time. Assemble, plug in the DMD/TO and have at it. If you buy a toy you get a toy. If you buy hobby grade, and Tamiya is the only one, you get a hobby grade tank.

The mounts for my units are made from 3 mm aluminium angle. Cheaper than steel, easier to work with for machining and lighter. My units weigh 50% more than stock but in a Tamiya that extra weight doesn't matter. If you knew what I make on these units you would question my sanity.

I had to LOL at your 'AK' reference. I am a bit familiar with that line of odes to world peace by Comrade Kalashnikov. Couple weeks ago we we were at Battery and some local unit had a couple tables set up and were inviting lads to field strip an automat. My lass and I wandered up, the young Sarjant didn't know who we are, and when he heard us speaking English he offered to me to strip the automat, saying that being foreign I would know nothing about that weapon. After clearing the weapon, and it was a parade model, I removed the muzzle brake and tossed it to him.