Fastmike Heng Long Worm Gear Drive by fastmike75

Last crawled date: 3 years ago

These have been discontinued and gears are no longer available.
This is an alternative gear drive setup for the Heng Long Battle Tanks. It can only be used with the "Fastmike HL Worm Gear Drive Set" that are available on eBay. The gear sets are manufactured from solid stainless steel stock with very close tolerances for the bearings. Gear set comes with aluminum spur gears that match the drive gears on the stock Heng Long RS380 motors. Each drive uses 5 rubber sealed RC car bearings instead of bushings for smooth power transfer. The drives weigh half of what the stock steel gear drive weighs, giving you more power and turning ease. The drive also gives you the flexibility to change the final gear ratio by changing the spur gear. The kit comes with a 28T tooth spur gear that matches the stock final drive ratio. Have 26T, 27T and 29T, 30T gears available. The 26T-27T gears will gear the tank up, faster top speed, but less turning power. The 29T, 30T gears will gear the tank down, slower speed but more power, quicker. You can use the stock motors and controllers from the tank or there are motor plates and shorter motor supports to use RS540 motors and controllers on the gear drive. Recommend a 48P, 38T tooth spur and a 48P, 16T-20T pinion gear on the RS540 motors. The Gear Drives are universal and will fit either short or long axle HL gear drives by switching sides with the gear cases on the mounting plates. The drives are smaller and should be able to retain stock components on most tank models. Some models will need post/s trimmed to use the drives. There are two different drive styles, the long and short axle drives. The long axle drives need a bearing button through the tank hull, these are chassis numbers 3838,3839,3889 and 3918. The short axle setup uses a bearing arm that holds a bearing next to the hull, these are chassis numbers 3818, 3819, 3848, 3849, 3859 and 3868. Some of the tank model numbers are unknown still and will update the information as I get it. There are pictures of drives in tanks on the fastmiketank website and will update as I get pictures from users.
The 3D printing is pretty easy on these. The Mount plates and the motor plates print best without raft or support, everything else needs raft and exterior support. Total print time is about 6.6 hours for everything. The main gear cases have a trim/break away piece to keep the motor mount plate surface straight. The gear cases where the screws screw in should be glued with model glue, let to dry and drill at .086". All of the other places a #4 screw goes through something it is a .116"-.120" hole, Everywhere a #4 screw screws into something use a .086" drill bit, except for the motor mount plate screw holes need to be drilled to .093" or the screws will spread the cases apart. The locator pin holes on the mount plate should be drilled to .101". This gear drive uses the following fasteners and bearings for a full install of both units, (4) 5mx12mx4m MR125-2RS sealed ball bearings, (6) 8mx14mx4m MR148-2RS sealed ball bearings, (4) M2.5-0.45 x 5m Socket cap screws (RS380 motor screws), (14) #4 x 3/8" Pan Head Sheet Metal Screws, (10) #4 x 1/2" SMS, (8) #4 x 3/4" SMS, (2) 4-40 x 5/8" machine screws and nuts, (4) #4 flat washers, (2) 6" wire ties. If you use the RS540 motors you will need (4) M3-0.5 x 6M button head screws for the motors, (2) 48P, 38T spur gears for 5m shaft and (2) 16T-20T pinion gears for the motor.
In the files are two pages of JPG installation instructions.
The worm gear sets when available will be listed on Ebay. Will have sets with just the gears and gear sets with all of the bearings and fasteners for stock install. This was a three year project started with a YouTube video. Hope you enjoy the gear boxes.
Update, Dec 2017: added a new mount plate and bearing button for the Leopard 2A6 tank base # 3889 to be uses with the long axle setup.