HL Bulldog gearbox / motor question

[Jono77]

Hi, new here
I have had a look around but cannot find the info I am after.

Basically I upgraded the gearboxes on my tank to these ones from tankzone :

http://www.tankzone.co.uk/images/hl/stug/gb1.jpg" onclick="window.open(this.href);return false;

And they're rubbish - the motors can hardly move the thing and it gets red hot, even smokes - it can only manage (just) forward and back and no steering or the motors stall. There seems to be speed at no load if I take the tracks off, but absolutly zero torque on either side. The gearbox is as free as anything as well, no binding what so ever (oh it is running metal tracks). Initually I thought there was not enough weight on the tracks (they are being pulled taught) but adding weight simply makes the matter worse.

Is there any suggestion ? The battery seems OK and I have tried it using a conventional RC system and again, lots of speed but no torque.

Ultimatly I want to ditch the HL radio gear altogether and use my 8 channel futaba tx I use for all my models, but is there any advice on this motor issue ?
All I really want is a slow moving tank with lots of grunt

[Saxondog]

Are you sure th tracks and especially the drive sprockets are the correct set. But then as you have said the is no torque. have you tried to wire the motors directly from a battery? This would eliminate to control system as a cause if the condition is still present? If not the the RX18 unit could be at fault. Smoking motors are bad, do you still have the factory motors? Or are these in fact what you using? Are they mounted correctly? Are the pinion gears aligned correctly?

I am just suggesting idea's, trying to establish a process of elimination. Seems the motors are pulling to many amps, overloading the RX18. Try removing the motors as well, test with a direct battery connection and try to stall them.

Are you in the UK or US? I ask this to determine which vendors are best options for you. Sax

[Saxondog]

One other tool that may help is the Gearbox Calculator Download on this forum. Here is the link.

http://www.rctankwarfare.co.uk/forums/d ... ftware.php" onclick="window.open(this.href);return false;

[Jono77]

Thanks (haha 'tanks') for the pointers.
I tested them with just the sproket wheel and you could stop them no probs - I done thought to myself...oh these are not going to drive the tanky up my garden.
I do have a fair bit of experience with electornics and gears and I am stumped.
My only conclusion is both motors are fritz'd - whats odd is they deliver the rpm but you can hold stall the spindles with your fingers.
Either that of the battery is dead, I have known nicads to charge and then develop large internal resistnace under load - hmmm thinking of that the speaker DOES go quieter when you try to move forwards with the tracks on...

I am from UK btw
Any recomendations for a replacement motor - I dont want speed I want lots of torque.
I know the Bully has a prob with the fact the motors are directly opposite each other so tehre is limited space.

If anyone has any motor suggestions it'd be great to hear for you

thanks for your time.

[Saxondog]

Gruapner speed 400 motors, in my 20lbs. Tiger for over a year, torque and smooth operation. I have the Asiatam steel gearboxes 3:1 ratio 12tooth pinion gears or 11 tooth. Available through RCTANKWARS,OR Hobby Lobby Intr. Their not expensive and they work. Now Dave or Steve may have them I'm not sure? I will list all four links. The motors are 7.99 each through HBI. Dave Forgebear can be PM messaged on the forum, he may have these I just don't know.Also the link for fan cooling the RX18 IS INCLUDED
http://www.rctankwarfare.co.uk/forums/v ... +RX#p40142" onclick="window.open(this.href);return false;

http://rctankwars.com/" onclick="window.open(this.href);return false;
http://www.hobby-lobby.com/speed_400_7. ... 0_prd1.htm" onclick="window.open(this.href);return false;
http://www.welshdragonmodels.co.uk/" onclick="window.open(this.href);return false;

[Jono77]

Hi Saxondog - thanks for the reply.
I think my gearbox is reduced so the motors have no excuse really - charged my old NICAD up last night on my super-duper charger and it says it is taking full charge (so ace my charger tells current and voltage on and off load). Tested again this morning and the thing moves forward and back OK but will not turn on the spot (ie right stick full left or right) it tries but wont have it, if you push to 10 or 2 o'clock it just about manages it - again it moves a pretty high speed but the moment you put anything in the way like a slight elevation etc it will stall it...really strange.

I'll try the motors you suggest, as you say they're pretty cheap and see if that helps.
I have a feeling these were never upto the job when they were sold to me

[Saxondog]

I have used these motors for over a year and they work very well, when you change motors you need to run in the gearboxes.Cam shaft grinding compound works very well. This will smooth the gears and allow for a quieter running Tank.The link for Hobby Lobby will also provide pinion gears.So make sure you check that out as well.

[Jono77]

Hiya, I have just looked at the spreadsheets and feel a bit silly...
I have the asiatam low profile boxes and thought the stepped gears were there to spread the load of the gearbox, through the gears themselves and to prevent torque reaction from distoring the box...
Seems they are there for 2 speeds, I've just turned the final drive around on the output shaft and got a much lower gear ratio - and TORQUE ha-ha !

Its a bit noisy but there is some fantastic low speed action to be had and its much more scale - probably a bit slow if anything but the power is there and thats what tanks should be about, cool - gonna do some current and voltage checks on the motor to see what it is consuming. Makes me wonder why there are 2 gear settings though - true one has more speed but you cant turn at all, this ratio the thing can actually do tank stuff , 45 degree climbs and so on, strange...

[Saxondog]

I will admit I know very little about these gearboxes. My Tiger gearbox is the older Asiatam which was purchased with the Asiatam hull. The twin ratio may be for adding an addition reduction gears that goes between the motors and gearbox.

This is post should be helpful in the future to anyone having the same issue. Try running the gearboxes minus the sprocket to run in the gears,if you use the Valve grinding compound they will be quieter and run smoother.Most Auto parts stores sell this product in a small canister. Very happy you have worked it out,The torque is a good thing, my Tiger is a bit slow but I have coupled it to a stock Jagdpanther and with the Jagdpanther running full speed spinning tracks my Tiger was dragging it backwards, all torque. cheers Jono77

[Jono77]

No, thank you



The final drive gear is now on the outermost gear, give about 50:1 ratio - it's not what I would call slow, just scale - but the torque is huge, I've not been able to stop the tank at all - as long as the tracks make contact it'll pull itself up at any speed and flip on its back ! - looks really cool.
So happy with this now I'm gonna go and buy a T34/85