11/15/2020 at 10:31 •
FULL TRHOTTLE !
I wanted to use an IC engine as main power source from the very begining.
I chose a 196cc 4 800W (6.5hp) 4 stroke engine. It includes both manual and electric start. The engine is equipped with a centrifugal clutch, which simplifies my work a lot. It is a "LIFAN 168F-2D-B" engine.
TO BE CONTINUED....
11/14/2020 at 21:36 •
ON THE BOUNCE !
I will be using the torsion bar concept : This is a very compact and low maintainance suspension system.
I wil try to make an adjustable system, since I don't know the exact weight of the finished tank. It can also be useful to modify the initial strain to change the suspension behaviour if needed.
... and to tap ! 11 more to go ! The suspension blocks will be screwed to their mounts... ... and the mounts welde to the bottom plate I also welded U shaped profils to prevent the plate to bend too much under the torsion strain well, welding DOES induce strains from heating... 1300MP high strengh spring steel will be used for the torsion bars The torsion bar pivots inside bushings
11/14/2020 at 20:36 •
(continued from log "Gearbox Mk1")
Since I was going to face major problems with the Mk1 gearbox, I anticipated the construction of Mk2, featuring :
-Full metal shifting forks
-Additional shaft, allowing to dismount the gearbox more easily.
It features 4 reversible gears.
There are no synchronizers, jus basic dog clutches. The dog clutches are motioned by 9kg RC servos, from an arduino.
It is a semi-automated gearbox : when pushing "shift up" or "shift down", the algorithm does all the necessary steps to change gear.
It is a semi-intelligent gearbox that detects when errors occure (e.g. blocked mechanism) and acts accordingly.
The first trial turned to be pretty succesful and quite promissing :
From CAD.... ... to reality
Tensioners New metal forks Switch detecting dog clutch position
Arduino + radio module
The concept proves working pretty well (including at high speed) without load.
We'll have to test it again with the rest of the transmission, (double differential + steering system) ; under load once the chassis is done ; and under full load once the turret is complete...
05/17/2020 at 07:52 •
ALL WE HEAR IS RADIO GAGA
Since I didnt really learn electronics at school, I expectef the radio to be quite difficult to build. but it turned out easier than I thought, it's just a basic button box, with an Adruino, a screen, a 2.4GHz module and a battery of course. The box is 3D printed (SLA) and the pannel is made out of wod, laser cut.
HOMEMADE BRIDGE DIVIDER
05/16/2020 at 19:18 •
GETTING THE RIGHT FRAME OF MIND
Building the frame wasn't that hard, but much, much longer than I expected. I had to drill several hundreds of holes. I also had to be very patient and very cautious with positioning and maintaining the profils while welding. Since I am no professional welder, I had to improve some weldings after the polishing step revealed weaknesses. The most difficult part was to cut and weld the angled profiles properly.
From CAD... ... to reality
At first I made the frame in 2 parts : top and bottom
And it was a bad idea :
MUCH BETTER ! profil welding. I also Riveted a lot of nuts for potential mountings interfaces The bottom plate will be fixed to the chassis by these nuts Here we see the plate's nut inside the frame's hole
welding of the screws for engine mounts
Bottom plate Core of the frame assembled with gearbox Mk1, and engine... So far so good! Still got a lot of work... These front sections were very long to cut and assemble, because of the tricky angles Front view
Then i welded the left and right wings + turret mounting + rear section :
the pallets are 1m20*0.8m
After a few improvements on the fly, the frame is now complete. I then added a rust protection coating on every single surfaces. Just like real tanks, this one will have a long, and rough life. Let's protect it from the start.
Upside down view
05/16/2020 at 17:20 •
FULL SPEED AHEAD !
The gearbox design has been quite a challenge : I have a lot of mechanical power to transmit (4.8kW) with a high speed on one side and high torque on the other. Not to mention that the gearbox had to be as compact as possible to fit in the tank. I used roller chains instead of gears to make it easier to assemble run and maintain, as is it my first gearbox project.
The Mk1 Gearbox has never been tested. I figured I would obviously run to dangerous problems without tensioner sprockets. It would also to be difficult in maintainance to disconnect the gearbox output from the rest of transmission.
See you at the "Gearbox Mk2" post ;) !!
05/16/2020 at 17:06 •
Because history matters