RC Tank Warfare community hobby forum

Looks tight, what about cutting a clearance hole in the gearbox casing

Ludwig von wigbearer wrote: ↑Tue Jan 07, 2025 10:01 pm Looks tight, what about cutting a clearance hole in the gearbox casing

That's a thought.

I will take a look at that when I take the gearboxes out.

My preference would be to flatten the bare ends of the wires against the motor as much as possible and put some insulation between them and the gearbox sides, but if I cant do that, then making a clearance hole immediately in front of them would be a good option - but I would try to cover the hole from the inside to prevent grease flying out from the gears onto the motors or dust etc getting into the gears.

Good idea though - it could work!

Thanks!

You can solder the plate to the terminals, and then the wire to it, thus you will gain in the gap and will not have to saw the gearbox housing...
By analogy with the terminals in a car...

Pavel wrote: ↑Wed Jan 08, 2025 12:48 pm You can solder the plate to the terminals, and then the wire to it, thus you will gain in the gap and will not have to saw the gearbox housing...
By analogy with the terminals in a car...

Thats a good idea , you could solder a thin plate the motor terminal, put heat shrink on it then solder the motor wire on.

When I was putting the HAYA KIT Centurion together I did fit a pair of Red motors - but they looked so close together that I took them out and mentioned spacing the gearboxes a little further apart to accommodate them better ......at a later date.

At that time, I was under the impression that the Red motors were closer together on the Centurion due to it being a slightly smaller tank - but this was wrong (!) as I can now see that the motors are every but as close together on my Challenger 2 - and now I am thinking that the spacing between any of the Heng Long and and HAYA tanks gearboxes is more likely to be the same on all of them.

I have been mighty impressed with Meter rats videos of his Challenger 2 running at speed over terrain that my HAYA tanks couldn't even dream of (mine have problems running over my well cut and closely mown flat and level lawn) and the main difference in power is that he is running his with a pair of RED motors.

Although his RED motors are very close to the gearbox sides, they have a fraction more space between them than mine - and a fraction could be the difference between running as well as his tank does, or shorting-out in a puff of smoke !

The only difference that I can see is that Meter rat has the posh RED "Ultimate Edition 11" GEARBOXES in his tank, and I only have the standard Heng Long gearboxes (with metal gears)....but that shouldn't make any difference (should it?).

Much as I would like to have a pair of RED "Ultimate Edition 11" GEARBOXES in my Challenger 2 - I cannot find any to fit my Challenger 2 anywhere at the moment. I have been looking for a pair because I like things that are finished in red anodised alloy - and they are ball raced - so when I can find a pair, I will buy them - but for now I will work with what I have.

I sent a picture of my RED motors mounted in my metal gearboxes to Meter rat so he could see that mine were slightly closer together than his - and he suggested moving the gearboxes apart slightly! Great minds think alike (!) but Meter rat has the experience of running a Challenger 2 (I don't) and there are a couple of things that I did not know about running a Challenger 2 that this mod could actually help!

If I move each of the gearboxes outwards by as little as 0.5mm - 0.75mm I would gain between 1.0mm - 1.5mm extra clearance between the ends of the RED motors and the sides of the gearbox - and this would be enough to run them safely and give me enough space to put some insulation between them as well!

What I didn't know was that experienced Challenger 2 operators have found that adding a small washer inside the drive sprockets to space them outward a little can align the tracks better and this helps to stop them throwing tracks (especially heavy metal tracks) .

With this helpful information from Meter rat I will start work on spacing the gearboxes apart by approx + 1.5mm. This will make fitting the RED motors a little more "comfortable" and it may also help my metal tracks run better too!

Before removing the gearboxes I used a vernier to measure how much space there was between the outside of the gearbox and the inner wall of the moulded Challenger 2 hull, and it was about 7mm. This varies due to the plastic moulding, but 7mm is near enough for me to use as a guide when I (hopefully) refit them a little further apart.

The gearboxes are located on two moulded studs in the hull and are secured with two self tapping screws on the inside (accessed between the gears) and a third ST screw on the outside flange of each gearbox.

I need to elongate each of these 5 holes in the base of each gearbox inwards to allow the gearboxes to be mounted wider apart.

Each locating hole is 2.5mm round and each screw hole is 3mm round and each will be elongated by 0.75mm towards the inside. `I may elongate them by 1.0mm so I have some adjustment available to move the gearboxes out as close as 5mm to the inside edge of the hull side but I will fit them to 5.75mm.

Mr Zooma,
Do not look for the specific Challenger gearbox. The one required is the High/Low 59mm shaft length. They fit the Leopard 2A6, Challenger, and Abrams. The MATO 5.0 steel 5.1 long shaft might fit, but I have no experience of it. I will keep sending the £10 for praising my Challenger.

To enlarge the 5 mounting holes in each gearbox I first removed the motors.

I lengthened the 5 holes with a small round diamond file and needed to remove the gearbox side (the one that had the base plate on it) to gain easy access to all of the holes.

I check fitted the removed gearbox side plate for fit into the chassis before reassembling the gearbox and refitted the motors. I used some lock tight on the motor retaining screws and added a strip of Gaffa Tape to the side of gearbox that the end of the lower drive motor would sit against.

I also added a thin piece of Gaffa Tape to each terminal of the lower mounted motor to double insulate this possible area of contact.

Before fitting the gearboxes I took the opportunity to knock-out the plastic bearings (they were glued in!) so when I get some axle bearings I should be able to fit them from the outside.

The gearboxes were screwed back into the chassis tub and the motor wires were reconnected and everything was plugged into the board and a battery was connected and switched on. Everything worked OK and the motors run OK so everything seems to be OK.....I just need to work out how to reverse the throttle as the motors appear to be running backwards when forward throttle is selected. (Heng Long 7.0).

zooma wrote: ↑Wed Jan 08, 2025 8:38 pm Everything worked OK and the motors run OK so everything seems to be OK.....I just need to work out how to reverse the throttle as the motors appear to be running backwards when forward throttle is selected. (Heng Long 7.0).

There is now way to reverse the motors using the controller or MFU. You need to reverse the motor leads connected to the MFU. That's the only way to reverse the direction of the motors. It won't hurt anything. They can be run in either direction. Some of the red motors have the terminals wired backwards from the motor you are replacing. After reversing the motor, you may find that you need to swap the motors from M1 to M2 and M2 to M1 while also reversing the connection of the other motor. That may lead to red wires and black wires being paired together, but that is OK for the motors. Just don't do that on anything else except the rotation motor. DC motors don't care which side is wired positive or negative - UNLESS the motors are timed more forward or more reverse. The motors we use in these tanks should be neutrally timed.

A forward (positively) timed DC motor runs faster in the forward direction than the reverse direction. A reverse (negatively) timed DC motor runs faster in reverse than in the forward direction. A neutrally timed DC motor runs the same speed in forward or reverse.

Throw all that timing talk out the window for brushless motors...as they work differently than DC (direct current or brushed) motors.

If you find that your motors are wired red to black, I would definitely label them for future maintenance to save you the hassle of having to go through this whole process again.

"A forward (positively) timed DC motor runs faster in the forward...." That's interesting, tankme! I will keep that in mind.

You see, zooma, there's always someone who can learn from your, unh, exploits.

I also wonder how you kept all the little gears from saying "bye-bye" and scrambling off to Neverland when you had the motor mounts separated. I have tried opening various sorts of gearboxes and inevitably end up with an intriguing puzzle.