Starting the M41 Bulldog...

[Jarlath]

So as part of my "quarantine"; I'm rebuilding a Bulldog for use on the field... This was one of my used tank acquisitions.
This is not my first build (rebuild) of a tank, but it is one of the first that I am actually updating with some images as I go.

Start, a used M41 HL Bulldog. Metal tracks, drive sprocket, upgraded with steel gears/motors, magnetic hull, sealed battery compartment and a bulkhead brace.
Was still a BB unit that had been converted for easy internal hull access.
Started by removing tracks and road wheels.


Motors, magnets & bulkhead were existing.... (as were the weights on the front hull lip...)
Look at the plastic HL swing arms... (I may have to change those at a later date...)



3D printed Speaker mount installed and TK-40 mounting board mocked up.
The speaker box was purposely placed there to give a side for a battery to lean against.



A prototype next gen JCC recoil unit being installed.
(This one will use the direct recoil linkage. Optional spring/impact linkage will still be included in kits)



Since I am replacing the airsoft guts, I need to hog out some turret internals. In the upper half, I increase the opening for the mantlet as well.
Added in a stiffener to accommodate the torque generated by the HL elevation mechanism.



Lower turret half gets the mantlet and stiffener treatments as well.



Chopped the barrel off. Installed a brass recoil sleeve in the mantlet, decided to make it permanently attached to the recoil unit.
Actual plastic barrel is effectively a sleeve held on my a small M2 screw just on the underside of the barrel behind the fume extractor.
Also added the IR port tube in the mantlet.



Layout inside the turret. HID Flash wiring routed through the recoil unit and to the muzzle brake.
It is to be installed on a side wall of the turret. IR wiring not yet installed.



Showing off the tubing through the mantlet from the outside.
16mm OD tube w/ 1mm wall for the recoiling barrel. 7mm OD tube w/ 1mm wall for the IR emitter



Other angle for the turret (wires through the upper hatch to keep them out of the way...)



Added in a JCC Tamiya TBU base (trimmed to fit) and a 3D printed spacer in the cupola pocket.
That gives a correct height to have the hatch closed and not interfere with the TBU socket.


That's it for now... Next: to finish off the turret wiring

[Jarlath]

Before anyone asks, here is the mods done specifically to the recoil/barrel assembly...
The factory plastic barrel is molded into/glued to the mantlet. The aluminum airsoft tube is inside this plastic sleeve.


Had to cut off the plastic barrel at the mantlet front (Actually flush with the main front of the mantlet to allow excess barrel length to be shaved down and to recoil inside the brass tube.


Aluminum airsoft tube is CA'd into the JCC Recoil unit. Note the heavy sanded area of the plastic barrel and the gap between the plastic barrel and the recoil unit barrel mount.


Obviously with the plastic barrel's fume extractor and muzzle brake it cannot be removed by sliding it through the mantlet towards the recoil unit.


A small 2mm screw is threaded in the underside of the barrel to secure the plastic barrel onto the airsoft tube. This also ensures proper muzzle brake clocking/orientation.
Need to remove? Remove the retaining screw and slide the plastic barrel off.


Showing the 16mm OD x 14mm ID brass tube used as the gun barrel sleeve for recoiling. Heavily epoxied into place for strength.
I also epoxied the mantlet into a permanent mount on the recoil unit since there is clearance.

[43rdRecceReg]

It looks neatly engineered and promising. Following along with interest.

[Jarlath]

As I await access to work again so that I can design up the battery/MFU Board mounting blocks, I added an additional aluminum lower hull brace.


IR Emitter installation and routing completed. Added in a small loop for ensuring strain relief onto the IR Bulb.


View of the routing near the recoil unit. A small spacer on the elevation axis to ensure minimal side to side movement/skewing.


HID Flash Unit hot glued into turret and all loose wires are clamped to one of the turret screw posts.


Internals of the turret complete. Getting rid of the old clunky BB unit does make for a hell of a lot more room in the turret ring.


Lower plate of the turret installed. All wires from turret are roughly equal length.


Good angle showing the factory elevation unit and the amount or room in the turret. No turret plate alterations required for the servo.


The turret Ring thrown on for good measure. This one will keep the limited rotation turret ring...


The turret IR Emitter through the mantlet.


Barrel is nice and straight to the rest of the turret! Turret rebuild for IR, Flash & Recoil is now complete!


There is a lot of room through the turret ring now.... Just how much? Ruler sitting on the recoil unit at near horizonal elevation...


Just a side showing the amount of space to the recoil unit from the edge of the turret ring.

[c.rainford73]

Well done following your progress

[Jarlath]

3D printed tray for battery and a raised MFU board area installed.


Openings under the battery tray area to allow for the receiver's twin antenna to route.


Receiver is to be velcro'd to the inner edge of the rear bulkhead wall as shown.


A Clark TK-22 and it's mounting board positioned (I'll likely go to a TK-60 instead...)


Mocked up with the Speaker, Board, RX & a battery in place.

[Jarlath]

Installation of the power switch and simple wiring connection hookups to said switch
(Toggle switches do not last forever)


Overall lower hull wiring completed. I like to have a clean compartment which is organized as much as possible.


Receiver installed via Velcro strip. 4 channels at bottom are for the future Clark board (Tray fits TK-20 up to TK-40)
The upper connection on the receiver is for a power lead to my FPV system that will mount on the turret.


Close up of the vented Clark board tray I made up and the simple speaker/battery tray setup installed.
I have added a small 7mm wide x 2mm thick adhesive backed foam strip along the right edge of the battery tray.
Better to have the battery not shift too easily.


Son's Clark JT TK-22 board installed for installation and routing finalizing.
Max volume jumper and a el-cheapo NiMH battery


Final installments and fit-ups before adding the running gear back on.
You can see the two connectors sitting just above the hull edge.
Rear Brake Lights (white JST) and FPV Power (black Futaba)


Re-installation of the tracks and running gear. Cleaned up the rotating surfaces a bit.
Drive sprocket and tracks are metal, road wheels and idler are plastic. May have to look at metal arms at a later date.


Side shot of the running gear. The cross brace screw head has a ton of clearance from the track.


Butt shot of the lower tank hull showing the location of the main power switch. The missing pieces have always been missing.
Doubt I'll replace them as this is to be a pure battler... Little bits get broken all the time...


Gratuitous under the skirt/bottom hull shot showing the sealed up battery compartment.
Magnetic hull system and internal battery for ease of replacement. Always done to ALL my tanks...


The assembled M41 Bulldog. Ready to accept a Clark TK22/24/40 board and go IR Battle.
Wheel hub covers and a couple loose parts to add on are in a ziplock inside the tank.


3/4 front view showing the M41 ready for action. Paint and finicky detail work are not my forte.
I have friends who are excellent painters I may have to trade them some internal tank work for external tank work...



Now the question is which of these two lovely acquisitions will be next for an upgrade treatment...
PZ III, or Stug III? Both came from Dan Crowley (aka YHR) awhile back. Still look awesome to me...


The internals of the PZ III... (Hidden IR receivers and hit LED's in the cupola...)


The internals of the Stug…

Which one to do first....