New Low-Budget Truggy Brushless

[florianz]

Here we go,

I needed a new project, and I wanted to have a truggy for a long time. I'm on a budget, so I got myself a "ansmann Hogzilla" chassis w/out wheels, motor etc., almost new.
They sell it as a "monster-truck", but that's fine for me...



I am curious about the quality. The diffs seem to be very solid, they're packed in a case, and sit between two mounts. I have cleaned and "shimmed" the diffs. the way they designed the diff seems solid to me, but on the other hand, it's more work to change oil in the differentials.

The quality of the aluminium-chassis is pretty poor, and the original rear diff-stabilizer-bar was already bent. I replaced it by carbon, and installed a stiffening bar to prevent the chassis from getting bent. The bar is hollow and is made of titanium and used to be in my broken right leg (marrow nail)... but who cares, it's titanium, and it's a very simple solution. and - funny thing - I just had to cut off a bit, and fits just perfectly, it weights 83 grams, but is much more rugged then any average aluminium.

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http://s8.directupload.net/images/091030/temp/9lyjkuf8.jpg[/IMG]


I worked a bit on the steering-plate to get more steering. To get the COG centered as low as possible, I have placed the esc right behind the steering servo. Above the servo I will place the receiver. The motor sits right in the air-flow of the fan (I made a "tunnel"). Motor-mount and Torsen-Diff are taken from my Hobao Hyper 7-Conversion.

The position of the center-Diff is already a bit towards the right side, which is ideal.


The battery-mount has to be flexible, as my lipo-packs have different measurements. I like it simple and stable, and like that I can move the battey forward or backward.



The shocks needed some work, they're loosing oil, and the plate inside were loose. Further I increased the shock-travel. Total weight will be around 4,4 kg.

Next thing will be the shock-mounts, I will replace the weak aluminium-towers with some self-made ones (carbon).

The motor is a Losi xcelorin 1700 kv, which got cleaned, and bearings got replaced by some ceramic bearings. I sealed the magnet-bonding (kevlar) again with some super-glue.

The first runs with new 5s-turnigy-batteries have been great. The torsen is ideal for the longer chassis of the truggy; in the hyper 7, I had sometimes problems with wheelies when the torsen locked. this can happen here as well, but is more difficult to provoke. after the first runs I have to work on the steering, wich is too "soft" in the beginning and too "aggressive" in the end.

florian

[Dafni]

The titanium rod was in your leg? That's awesome! Way to go!

[florianz]

thanks

first point, I was just too lazy to build something made of carbon (I only have simple tools); and second, I didn't want to waste that beautiful titanium. and it's cool to drive around something that used to be in my bone... first, I wanted to get some wedding rings made by that rod, but its impossible to forge titanium.

it was a compound fracture, and the bar got removed from the shinbone 1,5 years after the accident. and now, it's useful again.

as I have learned from my very first brushless conversion with that "ansmann virus" buggy (cheap copy of a hyper 7 pbs), the chassis gets bent really easily. what can you expect from a budget product... so without something like that, I will soon have a problem.

the carbon/alu battery "tray" also stabilizes the chassis.

[florianz]

...I don't think that the condo at soi4 has anything to do with brushless... better check out yellow pages dude

[Unsullied_Spy]

You may want to add something to the battery tray to keep the battery from sliding forward and backward and possibly damaging cells. Otherwise it looks good for a budget build. Will a normal Hyper 7 chassis fit? Those things have been around so long that you should be able to pick one up cheap.

[BL_RV0]

Looks good Florian. How does it compare to your buggy?

[florianz]

Thanks for your feedback!

@Unsullied_Spy
you are right. The battery sits very tight, but still can move a bit forward, backward. So I took a stripe of velcro-Tape, which has the the same size like the aluminium wich is right beside the carbon-plate. Then I've put a velco-stripe on each battery (on the lower edge). like that it sits even on the carbon-fiber plate, but can't move anymore. very simple yet effective. the more simple, the lighter (less parts, screws etc.)

The case of the esc is made of aluminium, and like that the alu chassis works as a heatsink for the brushless controller.

The hyper 7 chassis won't fit. I converted already a hyper 7 with truggy-wheels (http://www.rc-monster.com/forum/showthread.php?t=20827).

If someone's looking for a budget buggy chassis, get a hyper 7. excellent quality (solid diffs, great plastic, it's almost impossible to brake a suspension arm), and it drives great. Spares are easy to get, and are cheap. Actually, because of the great overall quality of the hyper 7 I wanted to convert a Hyper st, but even used, they're expensive.

@BL_RVO
steering is a bit unpredictable, yet it drives very agile, probably more agile then the hyper 7 buggy, and at the moment, it's kinda easier to drive the hyper7. that really surprised me. so I have to work on the steering to get it more "smooth", have to change the "ackermann" I think (I have no idea). The truggy has quite a lot of weight at the front, and like that a lot of steering. Grip of the rear axle is ok at the moment, but In future I think I will get rid of the rear anti-roll-bar.

due to the low cog it's impossible to roll over the car. and the long suspension travel (negative travel) pays off on bumpy surface.

Compared to the hyper7, the truggy drives a bit "bitchy", I think just have to do some work on the setup. the torsen just kicks ass, the longer chassis makes it more difficult to cause backflips when the torsen locks. But, with that torsen driving is very different, you really have to get used to it. but as I said, no power slips to the front when hitting the throttle (and almost no balooning front wheels).

florian

[Unsullied_Spy]

Thanks for the input on the Torsen diff, I'd really like either a front or center torsen for my onroad Hyper 7 to make it more driveable but haven't really read enough about them to know if they were worth the money.