RC Tank Warfare community hobby forum

The BTR-80 is an 8×8 wheeled amphibious armoured personnel carrier (APC) designed in the Soviet Union. It was adopted in 1985 and replaced the previous BTR-60 and BTR-70 in the Soviet Army. It was first deployed during the Soviet–Afghan War and sold around the world. Main
armament is a 14.5 mm KPVT machine gun and secondary is a 7.62 mm PKT machine gun on a small turret. It has a crew of 3 and can carry 7 infantrymen.

After completing the BRDM-2 armored car that was done very fast, i decided to continue with the BTR-80 kit i had in inventory, but this is a completely different vehicle, and represents a much more complicated build.


The BTR-80 kit purchased from an individual from Russia a few years ago is a hollow resin hull, with the same turret as the BRDM-2, and a few other parts. I also have the 8 rubber wheels sold by the same vendor, especially made for these vehicles.

The inside is totally hollow. It is left to the builder to ponder on his situation. It actually led to some prolonged inconclusive thinking about the matter and it took some educated guesses to figure out a potential option for motorization, and everything else. Forget about WPL chassis or suspension parts, these axles are way too short in length to fit the much larger BTR-80. The resin hull is also quite heavy and needs some large motor to move around. There are now some Hooben vehicles on the market (BTR-4, Striker...) that could likely be a perfect fit but are too expensive for such build, and availability of parts is an issue.


The tires are meant to fit WPL rims, but which type to use will depend on the integration with the chassis.


After much analysis and reviewing my own build of the 8x8 Boxer GTK, i have decided to do something similar. Instead of purchasing complete dune buggies to strip the mechanical parts, i have decided to buy individual sets of metal upgrade parts for the WLTOYS A979 4x4 buggy and build on these. So, i lot of the build time for this vehicle is to find, select and purchase parts that can be put together in a huge DIY chassis.

Base plate, in order to reuse part of it.

Suspension elements
Shocks
Differential housing continuing on following post

Differential gears

Additional screw set. Although the parts came with some screws, this set provided some important missing ones, but i also needed to buy a complete set of regular M2 Hex bolts of different length.
Axial SCX-10 gearbox created for 1/10 RC vehicle. Very powerful, if you can install it...
RS-540 Brushed motor
SCX-10 drive shafts
For this build, i will be helped by an old MB Models 1/35 resin kit of the BTR-80. This will be handy for measurements but mainly the small details.

The first task is to create a base for the suspension. If i was equipped with a lot of tools, i could have made a metal base but i decided to keep it simple and create a thick plasticard base where i can easily drill holes, and correct any situations if mistakes are made.


continuing on following post

I had no instructions. The frontal suspension with steering was a real puzzle to build. Everything is linked together so when you remove one screw, 4 or 6 items fall on the floor, and need to be put back. Assembling these is really tricky. It's frustating when you are used to a tank suspension or gearbox that hold together on their own. Assembling these is a mental exercise in patience and perseverance.

Some sanding was required in order to avoid tie rods to touch and disrupt their operation.


In order to maximize the middle space allocated to the motor and main gearbox, i put the two steering elements facing each other.


The shaft was cut to the required length, one end needed to be recarved to fit the gear, and a hole created in the middle to match the new location for the larger gear.


Frontal set of steering suspension elements are in place.


The pins for the steering will later be linked together and operated by a servo, location still to be determined.


Starting on the rear suspension elements, no steering on these, so much simpler. The differential housing we dipped in paint at the factory, which impacts the screwing of the M2 bolts to hold them in place.


It was important to figure out the rotation direction for all the gears for the differentials. They can easily be inverted by placing the differential gear on the other side.


The two main suspension elements are assembled and in place. It probably looks much easier to do than i actually was. It took me two days of work to get to that point. The blue tie rods for the rear suspension were too short for some reason, i had to replace them with longer ones i had on inventory. Need all kind of stuff on inventory with such builds.


These suspension elements required and still require a lot of adjustments.

Here i am starting the planning for the motorization, and how to transfer the power from the main gearbox to the two individual shafts.


continuing on following post

In order to pass on the power of the gearbox to the two differential shafts, i had to cut the middle part of the tower. The main shaft will go through there.

Next step is to figure out the placement for the SCX-10 gearbox in the very limited space available in the middle section of the chassis.


It does not fit with the gearbox cover. So i deciced to cut the long bulged tip section of the cover that was in the way.


It fits, there is about 1.5mm to spare on both sides, between the differential housing at the front and the left suspension arm at the rear of the motor. Every mm count on such build.


The bulged tip section is replaced by a plasticard plate in order to keep dirt off the inside of the gearbox as much as possible.


Main gearbox is temporarily installed in place. It will later be reinforced in place after testing is conclusive.


Need to design a main drive shaft to the suspension elements and differential gearbox shafts.


The WLTOYS shaft are 5mm in diameter, and it was easy to find a ball bearing that match.


One of the trickiest part is to put the small rod centrally in the shaft. This is where the gear will slide into and lock itself to. Any misalignment creates big problems.


continuing on following post

Needed to create two main shafts of different sizes.

Got to find a simple way to install them on the towers above the differential housings, and work on the SCX-10 drive shafts to connect to the main gearbox.


The suspension and motorization of the BTR-80 has been designed and mostly completed. Any required reinforcement will be done after testing and fine tuning.


I have two sets of differential cups, i have decided to use the silver metal ones as they are more solid on the suspension element with steeting which are giving me some problems. The dog bone can lock on the wheel cup when steeting the vehicle in a specific angle. Looks like a design issue with the dog bone, the pins seems too short. I have ordered replacements that looked better, i'll see when i get them. It might also be a tie rod adjustment issue. For now, the build continues.


I want to install the wheel and tires for some testing. This is the connection designed for WLTOYS 1/18 buggies, not WPL rims. So i need to design some adapter.


The brass adapter parts, a 1.5mm rod and a 5mm brass tube section.


Brass rod in place


A had a few types of WPL rim available. I have selected this type (use on the WPL pickup) and completely remove the frontal details.


continuing on following post

Slot is made on the back of the rim for the rod


5mm brass tube with two grooves is inserted.


Rim with tire is inserted.


And the nut is installed.


Wheels are installed but Oh Boy, the tie rods on these suspension modules need a lot of adjustments to be strait and aligned.


Not sure if they will ever be perfect. Touch one rod on the steering modules and it impacts the other ones.


Time to dry fit and slide the hull in place to see what is the situation. I was waiting for this a long time. I need to raise the hull on top of the suspension plate by quite a few mm. It's ok, it provides more room for the electronics that will be inside.


Ground clearance is impacted by my decision to use a plastic bottom plate. As i said, someone with more skills could create a thinner plate in 2mm metal plate. It's always time to do one when all the design issues will have been resolved.


continuing on following post

Need to design a all around frame between the suspension plate and the hull, and i will reduce the thickness of the suspension plate all around, keeing the thickness in the middle only.


I have 30mm available inside for the turret rotation, perfect.


The battery will be on a platform at the back


Looking to put the control board on the right side of the central gearbox.


Need to fit the steering servo somewhere in there... or maybe in the tip of the vehicle.


The model as it stands today, with the turret deposited on top for the look.


That's it for now.

Regards, Louis

Another ambitious build. Fun to watch you build and solve those problems.

Definitely ambitious. That shell casting is pretty rough. That in itself is going to require a lot of work.

I am very impressed with how you put together these mechanical "puzzles". For me it's black magic.