[Joecollection18]

after doing the mauler, going after the warthog.
RC with real tracks, suspension, and amphibious capabilities.
YAT YAS

The prototype warthog was narrower, similar width to a mauler or mobat.
I cut the hull so that the tracks can be tucked in, and started a triple oring seal to keep as much water out as possible. Filled with grease, it should work.

I chose my older mauler custom suspension units, and truncated them to give them more travel. Those merkava like external individual units are easy to lay around and replace\service. No way I am installing torsion bars here.

The water propulsion will require two more motors driving props or jets in rear,
A mechanical engaging\disrngaging seems complicated, we shall see.

First, making the hull with a good drive, decent angles of approach and not too tippy attitude. Good hub protection and ease of maintenance/ swapping drive sprocket, hubs in case of seal failure or improvement. Water tends to get everywhere so it needs to be easy to add grease, fix, swap drives. Mind you I try to avoid metal and make most parts from printed plastic to keep the toy spirit.

I would like to keep as much of the warthog body as possible.

[saltymarine]

That’s some cool work there! Holly shit !!

[Joecollection18]

Until I can get back to the warthog, a few pics of printed XM-25 weapons

[Novacaine31]

This looks great already. Can't wait to see this hit the water. Your Joes will now have the perfect vehicle for assaulting Cobra Island!

[Dusty777]

impressed again.. Nice work

Warthog is one of my favorites

[Joecollection18]

Thanks
I am hoping to make it to Cobra Island shores this winter...
Going slow, since water can ruin things, making sure the hull is decent.
The final drives are cassettes that can be pulled from the sides should they need to be fixed or upgraded.
Once hull is finalized, a coat of epoxy should seal it.
The final drives, packed with grease should keep water intrusion to a minimum.

The upper hull is going to be a nightmare to seal. As a kid I remember how water splashing around entered from the engine bay and vision slots.

I am making three steps forward and two steps backwards. The suspension shown is not working well. The warthog is heavy and too nose heavy.
It tips forward past the front road wheel. Meaning The battery in the front is not a good idea. Sad because it would have simplified a single sealed Bay with all electronics with upper deck access where the square is.

I changed the geometry of the swingarms. Longer and less drastic angle. Roadwheels would not deflect in reverse and get caught, meaning in reverse the suspension would lock and not work, worse, it can pull a roadwheel and stress, potentially break a swingarm mount. Not acceptable.
The front roadwheel stations need to be very stiff while the last 2 rear stations need to be much softer.
Am hesitating using different springs or different station angles, swingarms.
Trying to standardize as much as possible.

Going low is an issue, like the mauler, the low belly tends to cause getting stuck. Since the warthog will sink a bit driving on soft soil, the higher the ground clearance the better. Right now a Joe can lay flat underneath and the warthog drives over without touching it.

I am using Mauler roadwheels for the mockup but will print black or OD green wheels for final version. I chose the larger diameter rather than the fake warthog molded roadwheels size for now.

The warthog looks cool with the nose riding high and rear squatting a bit. Not the other way around.
I am too lazy to recut the styrene hull sides, but a proper repositioning of the suspension stations could provide the stance I need.

As soon as I can seal the lower hull, a floatation test is due.
I am afraid the production warthog was widened to float better.
It is tall and heavy
I am considering a higher water line (deeper into the water) but if it lists too much and not float with a decent stance in the water, I might have to accept having the tracks wide apart from the hull like the toy... No convoy with mobats and mauler, no NATO certification to drive on narrow Dutch villages and no bridge layer crossings 😢

[Novacaine31]

Looking so good! Awesome craftsmanship. I hope you keep it narrowed. It's great that it'll fit the temp joe bridge. Have you thought of just adding ballast the bottom of the hull? add a bunch of coins then fill with resin? Or even something on the outside, like a flat zinc sheet, painted...maybe attached to the outer lower hull. I'm thinking of my work on pine car racers and I've used those bolt on weight plates. That'd reduce the ground clearance, which already sounds like a problem, but could be detachable. Paint it and it'd blend in.

Can't wait to hear about the water test. I'm curious to see if the tracks provide a decent amount of propulsion in the water.

[Joecollection18]

I hear you about ballasts. Adding weights on hobby grade RC is no big deal. I would like however to keep these projects closer to the toys they really are. This means avoiding the cast zinc swingarms, metal gears, etc...
As much plastic as I can and the least amount of metal.
From the lipo battery I moved to a nimh which is a heavier , flat battery under the crew floor for ballast. 2 extra motors in rear corners for water propulsion. Still too nose heavy.
There comes a threshold where the plastic swingarms will bend, crack and yield. The further away I am from that threshold the better .
I quickly tampered with a rear drive, with a rear mounted gearbox which would enable the front idler wheels to be moved drastically more forward. This move the CG further back, lengthens the wheelbase, better pitch stability, etc...
At the expense of an ugly crew compartment in rear where a large bulge eats away the clean floor.
The front fenders will have to be altered, a bit risky.
And .. A personal preference of mine, which is that I prefer drive sprocket in front when dealing with mud and loads of debris.
At a larger scale, like 1\16 and with metal sprockets, it is less of an issue. But I am using plastic sprockets at a size that I am not sure the small teeth will survive well. I like front drive because the track tends to be clean by the time it feeds onto the drive sprocket.
So.. Stale mate pros and cons.
I am leaning toward the earlier avenue with front drive but reluctant to lengthen the hull. The real Amtrac has 6 roadwheels each side and a longer wheelbase to accommodate the heavy, overhanging nose.
If I were to lengthen the warthog, it must look right and stay looking like the warthog. The rear corner towers are already not following the lines and adding another shape past them looks like a kludge. The gullwing doors are not ABS or styrene but more like polypropylene which does not glue, fuse or paint well. The crew rear doors are a whole other can of worms.
These are the kind of decisions decisions... Where project can go Nasa style until they get cancelled.

As for the tracks contributing to the propulsion, Chrysler in the 60s experimented with large models and found that fully exposed tracks, or fully covered tracks, were not as good as having the front upper and front sides covered, like the lvtp7. They also experimented with different track designs. The tracks moving in water can contribute a bit but not very efficiently, so a separate propulsion is still required.

I really can't wait myself to reach the moment of truth... When the warthog comes ashore. If water propulsion is not enough to generate ample momentum, combined with ample track grip onto the soft soil.. It can end up spinning tracks and never making it onto the beach... Unless a wake helps it!

[Joecollection18]

less talk, more videos:
https://youtu.be/ESaNNiNALxI
more videos on my channel.

[Novacaine31]

Watched the videos. Great progress. The control looks really good with nice subtle movements.