WBO2014 Aliens M577 APC

[mr crispy]

So it's about time I got rolling on the winter build off. Been going backwards and forwards trying to decide what to do but I've settled on something I've had brewing for a long time

I've been a fan of the film Aliens since way before I was old enough to see it, and being into RC the idea of building a driveable APC has always been in the back of my mind. Saying that it's never going to be a very capable off roader given that the film vehicle was built onto a 70 ton airliner tug but I'm going to attempt to stay as accurate to the film as I can, besides the 4 wheel steering and moving gun turret should make for a great looking party piece

So a few years ago I bought myself a new BF3 and as I built up the chassis I immediately thought this would be great to use under an Aliens APC. The symmetrical layout meant 4WS should be easy enough to rig up and swapping over to TL01 length suspension arms gave it an almost identical wheelbase for the width to an old Halcyon model kit I have from my static modeller days.

It's not in the best condition and it did get repainted and recruited into my Warhammer 40K army at some point but the important stuff is still there and will make a good template to follow. This will also help!

Luck played a part as I bagged a bargain WT01 chassis off eBay and I found using 96mm Ansmann Kong wheels & tyres meant that the distance between the axles and the width matched closely to the models proportions, the tread pattern isn't too far off either so I was happy.

Having got that far it got packed away for a time when I was ready to do all the major bodywork. If you know me then you know I'm easily distracted and it never quite got any further, in fact I thought there's no point not having a bit of fun with the chassis while I'm waiting for the right time so for the last year or more it's been my Monster Jeep!

TBH that was a lot of fun and only helped put off the Aliens build further! But with the winter build off going with the on screen theme I have the perfect excuse to dedicate the time to do the APC right.

So I'm in the process of reconfiguring the chassis with some TL01 arms and I've been collecting the parts I'll need. I intend to get the chassis working as 2WD and 4WS first and check everything is running ok. I'll strip it down to check how the gearbox has held up to the Monster Jeep abuse and relube and refit it. I might eventually go 4x4 with a 2nd gearbox as I have a suitable no limits ESC that should handle the twin motor set up nicely. Obviously being a scale, mostly plasticard build I won't be running any hot motors in there, something slow and torque biased should do the trick.

As mentioned the body will be constructed from plasticard and fit over the chassis. I want to have the main turret gun moving so it can start in a stowed horizontal position on rear of the car and swing up and forwards to a deployed position, just like in the film. Got a few ideas how that might work so it'll need a bit of trail and error I suspect. I also want LEDs and maybe a discreetly hidden MP3 player to blast out some soundtrack choons

I've already got the plasticard for the body and servo Y leads for the 4WS, wheels & tyres are sorted. Next on the shopping list I think I'll need a low profile steering servo for the front end, possibly the rear too but I'll wait until I mock up the body panels in cardboard before ordering those.

Once the suns out I'll get some current photos done and keep this post updated.

"So, what's the matter Private? You want me to get your slippers for you? GET TO WORK!"

Nic

[Wez-li]

"Gee would ya sarge?"

Looking forward to this build!

[Gruntfuggly]

Just don't drive it like Ripley when it's finished!

[Mad Ax]

Looks like a great build - I love the WT01 chassis, with a few mods it's a lot more versatile than it has any right to be!

Subscribed - will be watching your progress

[zomboided]

This is rubbish. Fix it with some spider legs and red LEDs.

[emory70]

Game over

[mr crispy]

Would you believe it? I decided to put other distractions aside and get going with this build at the weekend, only to discover the stockpile of cardboard cereal boxes I'd been saving to plan out the body panels had been recycled by my wife! It's gotta be the first time she's even thought about the recycle bin in years. Typical.

So anyway, before this gets too much like "the dog ate my homework" excuse I've stripped, cleaned, relubed and assembled the WT01 chassis into a narrowed 4WS version. Just waiting on a 2nd steering servo to arrive and I can make up the rear steering arms.

Here's how the chassis looked with the TL01 shorter suspension arms fitted for a quick test drive and check out of the FlySky 6ch 2.4g controller.

All went well although I've yet to try the FlySky software out on my laptop to fine tune the settings.

In front there you can see a 2nd set of front TL arms and steering gear that'll be replacing the standard rear end. Also there are some 10mm wider hex hubs and barrel nuts to expand the width slightly and clear the Ansmann tyres.

So first job was to take out the gearbox.

Anyone that's not had a WT01 or WR02 may not know but the gearbox is a seperate module held onto the frame with 8 screws. In the WR02 it comes pre-assembled with plastic bushes, a silvercan motor and pinion. You can buy this as a set for around £20 on eBay which makes it easy to replace the "fake" gearbox on the front end of the WT01 and turn it into 4x4. The suspension arms and shock mounts all fix directly onto the gear case as seen above.

Opening mine up I was reassured to find I had fitted metal shielded bearings internally and two rubber shielded bearings at the output cups a few years ago when I picked this up 2nd hand. This had kept all the crud on the outside and just left a light coating of grease on the plastic gears with no signs of wear.

The grey on the gears is a bit of moly grease I'd used, the pinion was an 18 tooth hardened item and also had no wear. Not bad having served as my tough basher for over a year. All was cleaned, lightly lubed and reassembled.

I then started on the rear arms, replacing the TL rears arms with another pair of front arms I had in the spares box. I salvaged the rubber sealed bearings from the old arms and fitted them into the new(ish) steering uprights with my trusty bearing removal tool.

It's an old wooden paint brush handle that has just the right taper to be able to be pushed into a bearing and pull it free.

The steering knuckles use an elongated ball end on the WT01 to help reduce the bump steer that comes from the direct linkage off the servo. I've only got one pair of the Tamiya items but I found that Maplins sells these brass PCB mounts that have an internal 3mm machine thread that a standard Tamiya ball end screws into nicely. At the other end they have a thread that's more like a self tapping screw and holds into plastic very well. Here I've shown the seperate parts at the top, them screwed together in the middle and the standard elongated Tamiya ball end at the bottom.

You can see the Maplins & ball end combination is a little longer than the standard Tamiya part and that also helps to align the steering geometry better, so I've used those on all 4 corners.

I also fitted them to a high torque servo saver to get the links as horizontal as I could without fouling the gear case.

The gearbox and steering arms all ready to be fitted back onto the frame.

Here's the extended hex hub and barrel nut compared to a standard Tamiya plastic hub. It's twice the thickness.

Because the barrel nut has to go through the wheel and over the drive cup axle I had to widen the hole in the wheel a little. It was just a 5 min job with a Dremel to do all 4 wheels.

So now with a slightly wider stance and steering at all the corners it looks like this.

I've left the long WT01 front bumper on as the body will extend forwards of the front wheel by apx one whole wheel diameter! All that plasticard will need protecting

A bit of 4WS action... well faked action ATM

Once the high torque metal geared servo arrives I'll hook up the rear steering and then I'll probably have to reverse wire it like I did in my BF3 build, it's not a long job but best to wait until I have both servos in my hand just incase they already turn in oppersite directions I wanted a high torque servo as I found the driven axle on my BF3 would steer further than the free rolling one once I did the 4WS conversion. I hope the stiffer servo & servo saver here will hold everything tighter.

Those wider hex hubs give the tyres plenty of clearance and better match the width of the models wheelbase compared to the wheel diameter.

There's still a fair bit of bump steer on full compression but it's much better than it was and let's be honest, this isn't ever going to be a fast, high performance runner

You can see I've got the steering links about as close to horizontal as I can.

Got the Y leads so once the metal servo arrives I'll get the 4WS connected and tested. Then I can get on with the body work and making that turret gun move

[mr crispy]

The metal servo turned up so I made the rear steering arms from threaded rod and got it all connected.

Fitted the FlySky 6ch gear and tried it out with the Y link but I haven't reversed the rear servo yet so it just crabbed sideways. I was about to but having confirmed I will need a low profile servo for the front I thought its best to wait until it arrives as it might already turn in the oppersite direction.

For now I thought I'd just use the other right/left channel for the rear servo and hooked it all up for a test drive.

Which went well although it was possibly the most awkward test drive in history as every channel needed to be reversed, but to do that I need to plug the TX into a laptop. I'll see if the included software loads and get it all set up.

[mr crispy]

Quick clip

I'm wondering if running it like this would be better? ATM the front steering and power are all on the right stick, the rear steering is on the left stick. That seemed a good layout even with everything turning backwards to the input With that and filming it wasn't the most user friendly experience!

[bromvw]

video removed mate ?

[mr crispy]

Yeah I hadn't made it public. Should be back up now.

I'm thinking being able to do this

Or this should make it a bit more fun to drive

As long as I can run the turret on the remaining channels this might be the way to go.

[bromvw]

It would be cool if you could drive it either way - very futuristic

[SteveU30]

Great job so far, I vote keep it flexible too!

[Trini2DBone]

Wow! That looks great! Can't wait to see the body done! I have all the alien movies as well as Prometheus ...lol! Big '80s SciFi fan here...!

[zomboided]

I was tryng to work out how to do this....is there any way that the third channel can be used to switch the function of the rear servo - so if it's on, it crabs, if it's off, it works opposite? Sure there's a really simple circuit there

[XV Pilot]

If the Flysky TX is all it cracked up to be, surely there will be mixing facilities to do that without any extra circuitry?

[ChrisRx718]

The only way I can think might work would be a simple receiver switch managing the connection between the signal wires on he servo and the receiver. Either that, or have one split the power to the servo on/ off at the flick of a switch? The steering wouldn't be 'fixed' per se, but the rear wheels would need to overcome the un-powered servo which would be quite stiff?

[mr crispy]

Don't know about this 6ch system but FlySky do a 4ch one for less than £20 that's a little more basic.

http://pages.ebay.com/link/?nav=item.view&alt=web&id=131299487801

With that you could have the same set up I have and just choose when you want to steer the rear wheels or leave them alone for "normal" front wheel steering.

You can of course just use a Y link and a 2nd servo that steers in the opposite direction if you don't want the crabbing ability. But that takes a little more fine tuning as you can't just use the TX trims to get it right as it'll adjust both servos.

[mr crispy]

Success! Loaded up the software for the FlySky CT6B TX and I did think I maybe had an issue with the cable... but searching the web for advice I found a great "How to" walk through at www.mycoolheli.com/t6config.html that even someone as computer illiterate as me could follow

So now I have a chassis that goes where I want it to, although it still feels pretty weird doing all the power and main steering on the right stick (it shouldn't to me as that's how Heng Long tank transmitters come as standard). I'll need to fiddle it some more but now I can get started on the bodywork.

[SteveU30]

Well technically this is kind of a tank!

[Mad Ax]

Great stuff - can't wait to see the body taking shape

[zomboided]

You should pressure wash your decking though, it's looking a little grubby.

[mr crispy]

Cheeky sod! No point doing that until spring mate, it'll just be damp until March anyway. It's great for wheel spinning, J turn action though

[Mad Ax]

Cheeky sod! No point doing that until spring mate, it'll just be damp until March anyway. It's great for wheel spinning, J turn action though

It looks like mine - which means it's also great for slipping over on when it's raining and landing flat on your back in a puddle

[SteveU30]

Nice one Arron, that's hilarious!