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HL 1\24 Leopard II - IR-BB Tank Gearbox swap

Posted: Fri Feb 03, 2023 3:53 pm
by modler
I bought this NEW GEN HL 1\24 Leopard II IR BB Tank used and of course it has an issue that the ebay seller did not mention in the ad (right side track slip under full throttle) :-<

After some back and forth with the seller, I got a partial refund and decided to fix the issue.

I have two OLD GEN HL 1/24 BB Tanks (Abrams + Type 90) that have been sitting around for a good while (due to primitive radio gear) and will use the OLD GEN Abrams gearbox as a replacement in the New GEN Leopard.

First thing was to disassemble the defective Leopard gearbox to see what the problem is. This involves removing the drive sprockets from the GB to get it apart. These drive sprockets are pressed on\off and are a bit tricky to remove without damage but with the right tools they come right off. The problem found, Leopard gearbox has a internal gear with broken teeth.

So after removing the drive sprockets, and outer axle white nylon bearings, then remove 4 screws, the gearbox comes apart. It is like a puzzle that comes apart and back together and is well designed. The old gen gearbox seems to be a bit more robust and is a little different in its internal design and appears to more robust than the NEW GEN GB. They are interchangeable so I will be swapping in the OLD GEN GB into the NEW GEN Leopard Tank to effect the repair.

Also I will do a mod to the gearbox that adds "liquid oil in the gearbox" like a real gearbox has that allows for superior lubrication. This involves drilling two holes in the top of each half of the GB casting.

JST connectors added so that GB can be swapped in\out quickly.

Re: HL 1\24 Leopard - I|R-BB Tank Gearbox swap

Posted: Fri Feb 03, 2023 9:26 pm
by tankme
Gotta love Ebayers that withhold information. Enjoy the new tank.

Re: HL 1\24 Leopard - I|R-BB Tank Gearbox swap

Posted: Sat Feb 04, 2023 11:52 pm
by modler
tankme wrote: Fri Feb 03, 2023 9:26 pm Gotta love Ebayers that withhold information. Enjoy the new tank.
Oh thank you tankme, I do enjoy these Larger scale Tanks (1\24) as they have full suspension and are very robust and fun to play with. Working on them is a little easier than 1\35 of course :D

I forget to mention that these HL OLD GEN gearboxes do have a SD. They have a ratchet slip mechanism that improves Left\Right tracking and is removable. It consists of a spring and 3 gear like parts that act like a "slip differential" between the motors that enhance Track tracking Forward and Reverse. I removed the SD feature from this GB when it was apart as I wanted to see how the Tank would work without it. The result is the L\R low speed Tank tracking is degraded as far as a new Tank driver would notice but for advanced Tankers would be a plus using right stick only driving. On this Tank, Left stick is for the main GUN movements and the RIGHT stick is for driving the Tank.

I will post some pictures of that SD as soon as I can.

Re: HL 1\24 Leopard - I|R-BB Tank Gearbox swap

Posted: Mon Feb 06, 2023 3:56 am
by Herr Dr. Professor
Put the SD back to keep it "low and slow, mean and clean." 8)

Re: HL 1\24 Leopard - I|R-BB Tank Gearbox swap

Posted: Mon Feb 06, 2023 7:54 pm
by modler
Herr Dr. Professor wrote: Mon Feb 06, 2023 3:56 am Put the SD back to keep it "low and slow, mean and clean." 8)
Yes I will do that. I will do a video of the steps required to reinstall the SD (Slip Differential) :D

Meanwhile, Here are pictures of the SD parts. The Broken Leopard Tank has been repaired using the OLD GEN gearbox from the Type 90 and is running very smooth and fast on its 2s LiPo. This one does not need the SD as it tracks very good Low and high speed. I like the speed in this one and with its full road wheel suspension, it is very smooth as well.

Re: HL 1\24 Leopard - I|R-BB Tank Gearbox swap

Posted: Tue Feb 07, 2023 3:02 am
by Herr Dr. Professor
I have seen that kind of slip mechanism before, and I cannot remember where or when. The much-derided HengLong PanTiger I have also uses a 27 MHz crystal TX/RX with the 'programmable' function. I have often heard that it's silly, grossly inaccurate junk, but I know that someday my heirs will be fighting over it while scoffing at the rest of my estate. :lolno:
"What hairs!? You ain't got no hairs!"