There's a couple of guys in your country over at the Panzerkettan forum who are running the Jamara 480 HS BB motors with the 3-1 gearboxes. One with El Mod and the other with the stock electronics. He even posted videos of it climbing a hill. With a cooling fan and or heatsink this should provide plenty of torque. The motors are long can 400s. Meaning they bolt right up but are longer so you may have to bend the tabs so they don't hit the other gearbox.

Why don't you contact them for further information? Like you, I cannot go buying 4 set of test motors this time around, only one set and even that is not in the budget!

hi james if only money grew on trees we wouldnt have any problems at all (my grandkids think its free at the a.t.m.)will follow with interest this topic still havnt made my mind up will have a look at panzerkettan to see what our fellow europeans are doing if i could find a source of metal gears i would build my own but the price ive found so far puts a stop on this its usualy cheaper to buy a complete gearbox unless you know of somewhere these are obtainable at a reasonable price



best regards pete

Mato hasn't sold just the gears in a long time. He was in China working on improving their quality at the factory. A couple of guys over here priced out what they would cost to make and mass produce, just the plates were over $100, it's cheaper to make your own from existing gearboxes or just buy them from the guys on ebay.

Several months ago, maybe a year ago, a fellow tanker did a step by step tutorial on how to make your own, PerryS did too. Once I get my new ones I may try to make a set with my spares for my Panther Tank. If it goes easy enough, for my M26A1 Pershing too.

My kids think we have an endless supply too! So does my wife sometimes! [:-]

hi james if i could get hold of the first gear in the henglong which is 3:1 ratio i could build my own i think asiatam sell just gears but you have to buy the full set a bit of a waste when i only need the one will keep looking on the net to see if i can find something that might work . till then it will just have to slow down on hills.i will not be defeted i always find a way it may take a little time got plenty of that im retried but i will keep an eye on the forum in case someone finds the solution


best regards pete

pete i have two metal gearboxes minus the final drive gear and axle if you are interested let me now
as they are sitting there collecting dust

fv432 have sent p.m. with regards to your offer

Hey guys,

Did some more testing but this flu is killing me!

Stock 3-1 Gearbox
Black Capped Suntech motors
Tiger Sprocket
.56 Amps
4.0 Watts
7.23 Volts
202 RPMs

Same as above with White Capped Suntechs
.18 Amps
7.5 Volts
1.2 Watts
105 RPMs

Low Profile Stug Gearbox
Black Capped 360 Suntechs
Tiger Sprocket
.24 Amps
7.42 Volts
1.5 Watts
240 RPMs

Running the White Capped Motors with the 3-1 Gearbox is out, the tank would CRAWL!

Hi,

Multiple threads on this subjec, maybe this could be a sticky?

Well, this is my testing/calculating results. Permax and Graupner motors is calculated values. HL motors is tested/measured in tank with El-Mod setup.

Regards

Jake

Hi jakeand.
Can you explain your table please?
1) What do you mean by 'no load Torque'
2) What units are you using?
3) What did you use to measure the motors?

Yours Simon M.

This post will be the one to post our test stuff, I'll keep most of it out of my builds.

I have a set of Long Can 400, # FK5202 12v. How would these run in a Tamiya Sherman or Panther with stock trans or with a 3:1 impact trans.

Hi Simon,

1. For calculated values, No Load Amp. spec. from manufacturer (Motor spinning free, No prop, No gearbox) For measured values, Motor in tank with gearbox and tracks.
2. Newton
3. Tillquist multimeter and a Testo rpm meter. Kyoritsu amp meter was temporary.

More details: http://www.rcuniverse.com/forum/m_70...tm.htm#7044893

Regards

Jake

Hi jakeand. Have you looked here ? http://www.mabuchi-motor.co.jp/en_US...ic/t_0201.html Excellent article on small DC motor specifications. I have a problem with you 'no load' torque. surely this should be 0. And your torque should me in newtons per unit length, so what is your unit length? Also why 5.5v not 7.2v. Finlay since these motors are quite weak, you would of been better to measure RPM with a strobe. When I measured these motors I found they were repeatable in volts to RPM, the so called 'K' factor, but the stall current was difficult to repeat, due to heating and phase position. This is why I have not published them.

Yours Simon M.

El Mod electronics limits voltage to the motors at 5.5v.

Hi Simon!

Thx for the link!

“I have a problem with you 'no load' torque�

Yes me too…but the only way for me to compare

“surely this should be 0�

Not 100% sure about that. If Torque 0, Amps/Watts also 0 ?

“And your torque should me in newtons per unit length, so what is your unit length?�

Yep, using this: Watt / (Rpm / 702,3)=Ncm (Value 702,This value is maybe not 100% correct)

“Also why 5.5v not 7.2v�

As Swath stated, voltage cut by El-Mod for Tiger settings

“Finlay since these motors are quite weak, you would of been better to measure RPM with a strobe�

Yes, but with Motor+Gearbox, measuring at the drivesprocket is no problem

“When I measured these motors I found they were repeatable in volts to RPM, the so called 'K' factor�

Yes, used Volt/rpm konstant for calculated values (rpm at 5,5 volts)

“but the stall current was difficult to repeat, due to heating and phase position�

Stall current is just a second before things begin to go up in smoke…I think its better to load/brake the motor under control….

Its Time to build a Dynamometer!

“This is why I have not published them�

Feel free to publish your findings, you are with friends![)]

This was my way to compare different motor/gearbox setups, a combination of measured real values and calculated values. The method is a bit simplified, e.g. motor efficiency, gearbox efficiency, rpm when loaded.

Not 100% perfect, but give you a hint what you could expect.

Best regards

Jake

Hi Jake,
Sorry for the slow reply, my machine went down soon after I wrote my last piece.

No if this is so then efficiency of motor would be 100%. (true the motor Must be producing some torque, but this is only what is required to overcome any resistance, air or frictional, and thus unusable, so ignored)

For a DC motor and a fixed voltage it works like this

Max RPM = No Load = 0Nm
0 RPM = Max Load = Max Torque.

Since motor power is a function of torque and RPM it follows that the motor is producing no power at these points, BUT is using power, thus the efficiency is 0.

Referring to the link, http://www.mabuchi-motor.co.jp/en_US...ic/t_0201.html , if you click the About Performance Chart link in the left, it explains quite clearly the different bits of the graph. What you have produced in you chart is useful, but I think needs a little more work.

I tested my motors out of the gearboxes, as I wanted to remove as many vairabls as possible.
Then stepping the voltage up at 0.5v steps to 10v noting with a strobe the RPM. From this I was able to find the motors ‘K’ value, (Volts / RPM).

Regards stall current.
Again a bit of physics. When a motor is stationary it produces no back EMF, that is to say the source only ‘sees’ the DC resistance of the motor. Thus current can be found using ohms law. And since torque is a function of current, along with a ‘motor factor’, we can deduce what torque can be produced for a given current flow. So I again I measured the pull the motor gave at differing current limits, in 0.5A steps to 3A. I used a simple spring scale attached to the shaft of the motor via steel cable. Measured the diameter of the shaft and calculated is equivalent Nm.
This is where the repeatiabity failed, and I ran out of time to make a clutch type Dynamometer, hence not been published.

I chose not to included the gearboxes in my testing as I find all of them such poor engineering quality, there results will vary wildly from gearbox to gearbox.

Interesting that El-Mod choose to limit the voltage at 5.5v. I would of limited the RPM, especially since they seem to use quite a clever microcontroller setup.


Yours Simon M.

Hi Jake,
Where did you find the motor manufacturers data? I'd like to check my findings against them. Also I want to see what the final drive shaft torque should be!

Yours Simon M.

I have a quick dumb question that didn't warrant a new thread for:

I'm getting a metal gearbox HL Tiger from BananaHobby when they restock, but I'm not going to do any modeling to it until the fall when I go back to school... but I want to play around driving it for a few weeks before I go off to my summer camp job. Is it worth my time to break in the motors and gears when I get it? Also, as it's a metal track and gear one... I'll probably want to reduce the ratio in the fall when I have access to a friend who can CNC Machine me up some new gears... am I going to have to re-break in any new gears I add to the tranny? I'm a little confused as to why the gears need breaking in... the FAQ explains why to break in motors, but the gears don't really make sense to me.

At the very least you should inspect the gears before you run the tank. If they're too tight a motor could stall and blow your board. All it takes is an evening to pull the gearboxes and break them in after the motors.

As for breaking them in again when you add a new gear, maybe so. You'll know whether or not by how freely they spin.

The gears are made from white metal and until recently varied quite a bit in their tolerances. These are $100 tanks after all.

Hi Simon,

You have to excuse my late answer, but I and the family are moving to a new house in a couple of weeks, so I have limited time for my hobbies at the moment……

Some links:

Graupner 400
http://www.hobby-lobby.com/speed400.htm
https://shop.graupner.de/webuerp/servlet/AI?ARTN=1794


Jamara 480
http://www.jamara-modelltechnik.de/i...1_LiPower.html


Heng Long /Suntech
http://www.torro-shop.de/product_inf...c19f893a6dea16

http://stdevltd.manufacturer.globals.../DC-Motors.htm

Multiplex/Permax 400-480
http://www.mft.nu/?cid=124498

From Swathdiver: http://www.rcuniverse.com/forum/m_55..._motors/tm.htm

http://www.rcuniverse.com/forum/m_52...untechs/tm.htm

If you PM your e-mail address to me, I will send you my motor/gear spreadsheet, maybe we can develop it together for better accuracy? It could be a nice tool for other fellow tankers.

Regards

Jake

Hi Jake,
I'd love to send you what I've got, but my PC mother board died taking the raid disks with it! At this moment I'm tring to recover the files.

Yours Simon M.

Hey guys,

We get a lot of requests for the RX-14 board and Heng Long has not massed produced them or at least sent them to us in the US on a regular basis. And we cannot get them over here unless Mato is now getting them, which I doubt! My therory is the board is not as robust as the RX-13 for rugged use? But maybe you guys could help to prove me wrong, while your getting this gearbox data can you use the same setup and get the perfomance data from the two different boards and let us know the results???

The Blitz

Hi Blitz,
Yup your correct, the RX-14 is a rare animal. I've only got one and have yet to reverse engineer it. I've had a few personal issues at this end including a trip to hospital, along with a very dead PC haven't been able to concentrate much else. I hope to be in better shape next week so will restart in earnest

Yours Simon M.

I've got 6 RX 14s


Rob

Hi guys Just been testing my home made gearboxes there were standard heng long gears but with an extra 3,5:1 reduction with them only just broken in thought i would take it easy to start so been running it with white cap motors boy has it got some torque not very fast i would say just over half speed but will it climb the only thing that will stop it is losing grip will try an angle slope tomorrow see what angle it will climb then will fit black cap and try again.


regards pete