Brushless Virus/hyper 7 Buggy/truggy build

[florianz]

hi,

as my current brushless buggy (low budged german brand ansmann virus w. truggy tires) was in a bad condition and also required some new spares, I decided to do it all new. I am on a budget at the moment, so I got some spares on ebay uk for a hyper7 buggy. These spares are much better in quality then the ansmann-stuff. These parts fit perfectly, and shipping to Germany was cheap.


I have already diffs of the hyper 7, so I now got myself the rear suspension, front/rear bumper of hyperST, center-diff holder, new chassis, front shocks.

The rear shock-tower is made of 5mm epoxy, the front is a sandwich of gfk/cfk and has already proven very rigid. its actually rock solid and survived all crashes, the alu-thing on it is like a skid-plate and protects it. The rear one is 2 grams lighter then the original (weak) one made of aluminium.... wow ;-).

things that have proven to be rigid or useful are also used in the „new“ buggy. The hole for the center diff in the chassis I have glued with a piece of aluminium.


The steering servo will hold the esc, like that I get mass to the front. Worked well so far. I made a kind of top-deck to keep it stable. It's made of 5mm gfk. A little torsion might be possible, but it's stable. Like that I have enough space for the esc in the front and for the motor.


behind the black cfk in the middle you find the center diff, along there it will be the position for the lipo. it kinda leans on there...


I want to keep the center of gravity as low and central as possible. It's all pretty close together, but it worked well so far. Further the solutions have to be simple and stable.

I will use 5s lipo on the 1700kv losi, w. a modded cheapo-200a esc.

To be continued.
florian

[florianz]

hey folks,

I have been busy the last days and the rebuild is almost finished. the steering now has bearings, as the sintered bearings were quite worn out. I 've got the bearings from broken servos, I' ve made it dustproof with some pieces of foam, we will see how long that works.



the lipo sits safe in that position, worked like that well in the past.

The weight like that is 3,6 kg. with the fans, the ubec I can't get it lighter. I had a look at the worn out crime-fighter truggy wheels, they have about 280 grams each, heavy... . and the fans are required, like that i can have trouble-free hard bashing with motor-temperatures around 50-60 deg./122-140f. the losi-heatsink is very hard to get, but like that it works great. due to the mudguards, the heat stays inside.

the cheapo-esc has a good throttle-response, no cogging, got modded w. bigger power-caps, but a crappy break of course. the xcelorin esc is not available currently here in germany:



The mudguards have proven useful, the one on the right hand side is not finished yet. Acutally I have no battery tray, but like that it worked very well in the past. I want to keep it as simple as possible.

what do you think about the weight? sooner or later I get my self new truggy-wheels which are a bit lighter, but still I will be over the 4 kg.
florian

[suicideneil]

4Kgs isnt too bad for a fully loaded truggy, especially whehn its the same power train as would normally be used in a 5-6kg truck afterall. I loike your chassis stiffener bar, looks like it does a good job to prevent chassis flex. Whilst everything fits on the chassis okay, the layout isnt the cleanest I've ever seen, but with a bit of thought and effort it could be tidied up I reckon- stick the rx behind the lipo and get make a simple tray for the lipo that bolts to the chassis to hold it more securely. If the brakes are rubbish and you cant afford a better esc at the moment, think about a mechanical brake if theres room somewhere to mount the servo and linkages.

Overall not that bad, not bad at all.

[florianz]

thanks for your feedback. well, its a rebuild, the first build was messier... but worked very well for many months.

it is difficult to get it tidy, with fan, ubec, esc etc... but I tried my best to keep it clean. I also tried to solve it all a bit different than other conversions, thats the point. I had the battery already like that in the old buggy, and it is absolutely safe. a tray is just extra-weight. less is better.

well, the esc: I ordered already a losi xcelorin, but after a month I was told it's not available at the moment. its's almost impossible to get it here, but the price-tag would have been interesting (about 170 usd). the mmm ist too expensive here in germany, and I don't really want to order things like that overseas (service). maybe I will order it at rcm, the price is right. In my point of view the losi is a good deal, I have a prog-card (mmm not), I have usb-wiring (ezrun not, hard to get new firmware), good service on their website for firmware-updates. like that, the losi has same price like the ezrun. There is a new prog-card out now for the ezrun, with which you can do updates for the esc (about 30 usd). the losi is up to 5s, that's fine for me. but right now I am short with money... for mech. brake therse's no space at all...

I'll go for a bash today, curious how the new compononents are like

florian

[florianz]

I had 4 lipos in a row today, without big problems. I have new (old) wheels I got cheap on ebay once. I have no Idea wich model they belong to. I have put some harder foam inside, to get the wheel more stable.


the diameter is slightly less than the crime-fighter truggy wheels (where one tyre is damaged). so I guess I need a 14t pinion, accelleration w. the 13t was a bit less then w. cf-wheels. top-speed was also a bit less.

on dusty ground the grip of the crime fighter was much better, but jumps and landing was by far better with these wheels. still I have better ground clarence then w. buggy wheels. these new old wheels are, even whith the new foam inside, about 80-100 grams lighter each.

best jumps today were around 10 meters, most times landed on all four wheels, just lovely.

the front bumper did a great job when I didn't land perfectly... also the new chassis has a great handling. I've put some weight (30g) to the front, so handling is just great now (less wheeling).
was good fun today
:D
flo

[florianz]

Just recently I've got myself an ofna torsen diff for the center.
pics




I've added some high pressure grease and some oil like that it works smoothly. A brushless-setup is just perfect for the torsen (balooning of front tires). there must be a solid reason that a "hummer" or a "audi quattro" have torsen diffs. and when it's ok for a hummer, it's ok for my buggy...

from my point of view, driving with the torsen is very different, you just can't compare it with a 100k-oil-center-differential. The torsen puts up to 80 % of the power to the axle with grip. That means you can't pull the throttle like before, this ends up in backflips. U must be much more sensitive with the trottle... in curves I think handling is also better than wtih a 100k diff. what can I say, It's just amazing, when bashing, acceleration is far better (being careful with the throttle!), you can get more power to the ground. almost NO pizzawheels in the front wow. I had to reduce the timing of the motor down to zero, just too much power...

as it is a buggy-chassis I have put some weight to the front. somehow reminds me of a quote I've read here: like an electric screwdriver on stereoids...

As my plane esc finally died from a bad soldering, I have time for a makeover of the buggy and to have a look at the torsen. There is NO wear after about 8 lipos. I've cleaned it, greased it and have put a bit of 15w40 engine motor oil into it. Like that, the grease is thinner and gets everywhere. just some normal oil would not be sufficient. Now the torsen works even smoother than before.

I increased the space of the "middle deck" above the steering servo, so I can place the new esc there (jamara flash, but not working on 5s yet...). the motor mount is super stiff. It's good when the chassis can flex a bit (torsion-wise), but NOT around the center diff.

My kind-of battery tray works great for many months now. Just once after a bad crash I lost the battery. I made it like that 'cos I like it simple. I dont't want to add a tray, some more scews etc, which is just weight. like that it's safe and simple. I know it has less "bling"-factor then e.g. a tekno kit, but, it's all self made, based on own ideas and, most important, it works well. the self made center bar is doing a great job, and the self-made front and back shock towers are just rock solid. aluminium is not always the first choice.



I have redone the Motormount a litte bit:


the motor mount is super stiff. It's good when the chassis can flex a bit (torsion-wise), but NOT around the center diff.




I am still very impressed of the losi motor, great torque; I have sealed the unused holes of the front endbell; sand and dirt are no good for the kevlar-bonding of the rotor.
These losi motors would deserve more attention.

florian

[Mentat]

very nice frankenstein ride. I am very impressed with the motor mount, the carbon fiber is smart. Id like to see some video of it in action.

[florianz]

frankenstein ride, I guess that's a compliment

as soon s I have a working esc I will make a new movie. this is an older one,

http://www.youtube.com/watch?v=8gghhDSQf0s

with a 80mm plane motor (similar to the 80mm 1300kv ammo), and a 200a plane esc. when I get my new esc I hope it's as reliable as the plane esc's. just great stuff.

the losi has about the same torque, I really like that. the 80mm motor died from heat... about 1300kv on 5s is not enough, so gearing was too long/large, unfortunately.

the idea of the composite-mount was that it's easier to build (with the tools I have). screw the carbon on the diff-mount, put the alu-braket to the right position, glue it, and do the finish. further, it is absolutely stiff and rigid, and in the perfect right angle. the aluminium bracket provides the heat transfer to the chassis.

I favor glass/carbonfiber over aluminium in many cases. like the shocktowers, just indestructible...

[Mentat]

yes Frankenstein ride is a compliment. Im digging, nothing like custom. I myself am doing a custom truggy. Hope to start it soon. i thought epoxy was for gluing things? can you explain what you did exactly to make the rear tower? also i notice that there is kind of brace that runs the length of the frankentstein ride, what is it?

[florianz]

actually, I've been thinking to choose frankenstein as my nickname for a long time... harr harr harr...

[Mentat]

if i recall isnt that the origins of the story germany?

[florianz]

Yep! I'm based here in Hamburg; it started w/ the ansmann virus buggy (german "brand"), which turned out to be one big problem...
that's why I changed to hyper 7 parts, bit by bit.

[Mentat]

Still wanting to know about this epoxy and brace as posted above?

[florianz]

Originally Posted by Mentat

Still wanting to know about this epoxy and brace as posted above?

hey, quite easy to do:

1. The Material
The motor mount is made of small pieces of carbon and glassfiber composites, they also call it "epoxy" "epoxyd"-composites, "GFC". I bought them very cheap at egay. they are actually leftover pieces, but good enough for me.
the green looking gfc-epoxy of the center bar/rear shock mount was an 20x30cm piece, 5mm strong, industrial standard.

2. The glue
There is a 2-component glue/epoxy glue available here, which can be tempered at about 70deg. c. like that you can process the glue for about an hour; to get it finished, I put the pieces into the oven (in the kitchen) for an hour. like that its ready quite quickly, and very, very solid. I really love that stuff (uhu endfest 300). when mixing the 2 substances you also can vary the stiffness or elasticity of the glue.

3. How-to:
The green center stabilizing bar and rear shock mount is made of 5mm quality glass-fiber-composite/epoxy. the original shock tower was made of very weak aluminium, just crap. But I didn't want to buy option parts for expensive $$$, so I made them myself.

I take the original shock tower, lay it on the epoxy; take 2 molegrips to fasten it, drill the first holes and put some screws thru. like that it's easy to work with the saw, drill and file. and it's absolutely exact. the same way the front shock mount was made, material is a sandwich of carbon and epoxy (small leftover pieces). funny: the glassfiber/epoxy shock tower weighs 2 gram less then the original one...
I really recommend that to everyone, who's shock towers are worn out or not stable. better than any option parts. and not expensive.

the center bar is just made by "trial and error". with saw and file. the reason was that there is almost no space for the original aluminium diff-bar (whats its name again), and on the front the space is needed for the esc.

the motor mount is made by a piece of carbon and an aluminium-brace. both pieces put into position, molegrip, glue.

all hand-made with a drill, saw, file, no cnc...

and a bit of madness... huaaa....

florian

[Mentat]

genius, i am really impressed with your frankenstein ride. honestly. You have give me lots of ideals on mine. cheers!