Another Gmaxx is born

[jordan...]

nice work with the battery tray looks real professional. Can i ask how you cut those rectangular slots out? Oh and are you still going to get the Medusa?

jordan

[suicideneil]

Yep, still gunning for a 70mm medusa, or castle neu- time frame for each is similar so I'll play it by ear, as us brits say, lol.

As for the slots, I drilled two holes about 30mm apart, then used my trusty dremel with a cutting disc to join the two holes, creating a rough slot. I then used my selection of needle files to smooth out the roughness and square-out the ends, creating a perfect little rectangle about 30mm long by 5mm wide. It would be much easier with a vertical mill, or drill press even, but its still perfectly do-able with even the most basic of handtools.

[suicideneil]

More news (good or bad) tomorrow, if the weather plays nice.

hey neil, hows it? is that one of the motors from hobby city? looks like one of the feigao imitations?

[suicideneil]

Yep, it is one of the Hobbycity feigao knock-offs (copy of a copy...hmm)- 9XL to be precise (1900kv).

Well, the weather did play nice, so I went to the park, and hammered the absolute shite out of the truck and esc, literally; video will follow, just got to edit it up- it'll be a good one this time!

Findings:

Motor = cheap, cheerful, hot... hot hot hot. On 4s2p + 62/24 I was getting upto 160*f on the motor, around 110-120*f on the lipos, and esc was about 90*f or so. I then went upto 58/24, and the motor temps dropped to about 140*f, lipos stayed the same, so too with the esc roughly. On 6s2p of A123 cells, the motor temps peaked at about 183*f on 58/24, but I was having so much fun with the insane speed and power, I didnt bother to gear down or up to see what effect that would have. The esc got upto about 100*f, but the A123s barely climbed above ambient (70*f or so, nice sunny and breezy day). All in all very pleased with the power, but the motor temps need to be watched closely- cooling down breaks are advised if bashing for long periods.

Mamba Monster = highly impressed with the temps, and it didnt crap out on me, neither did the fan. Only issue I have really is the case design- after landing on my lid from endos or backflips, the esc case would pop open, exposing the fragile guts. I think this needs to be addressed somehow with larger clips joining the upper & lower halfs together, or perhaps screws etc. I will be using some long zipties in the meantime, and that should suffice. For all its smoothness, I did manage to get some cogging and/or hesitation from the esc, mainly from standing starts, or when the truck was some distance from me; could put that down to glitching maybe, or lack of power in the batts when I tried to nail it, hard to say. Very good esc so far, just hoping it stays that way.

Cheapo 4s lipos = performed beautifully. Temps were a little higher than I would like at about 120*f, but thats not too high really, considering what I was asking of $30 each lipos. I think if I dont pick up some swangs or zippies, I will get some more ebay lipos, maybe a pair of 5s items to run in parallel (speed was great with 4s, but with 5s its just bonkers).

A123 cells = fantastic. Never got warm, and provided amazing punch all the way to the end of the run, when they suddenly dumped (and I mean DUMPED), just like I have read about for so long. I mean, there was hardly any drop in voltage/speed all during the 15-20 minute run, then after doing one nice long drag, and went to bring it back to me and it just died within a couple feet... after doing a 40-45mph sprint. Its nice to know the batts arent harmed by that kind of dumping action, and it allows you to time much more accurately how long a run had lasted, vs waiting for an LVC to trip, even if you just drop the cell voltage below 3.0v for a split second.

LVC = I love that thing. I didnt use the built in one of the esc, I prefer to jusdge when the batts are really dying myself. The little red led of the LVC is great- only comes on (very bright, even on a sunny day) when you nail the throttle and the cell voltage dips for a second, then it goes out as the voltage recovers. Much better than a hard cut-off, especially if using cheaper batts that might have lower C ratings. I just have to pick up a 5s version for my new cheapo lipos, not a bad investment for about $10.

TRUCK = rear body posts hanging off from flips, right-rear tire lost its glue and repeatedly came off the rim, tyres massively unbalanced, and the damn thing refused to track straight- need to poke at steering linkages I think. Scariest thing is crusing along at half throttle, then punching it, and watching the truck rear up onto one wheel, or lurching violently to one side as you try to control all that power and speed. Definately going to pick up some proper offroad tyres- Im thinking either zombiemaxxes, or.... ? Remember that Im a fickle-minded numb skull who only likes stuff that looks good, rather than performs well...

Will post a few pics and video later- need food now, hungry.

looks like that motor isnt to bad for 30 bucks huh? 140 on it with 4s, is it faster than the hvmaxx, on 4s? i bet 6s was insaine huh? lol need to get some vids there neil, esspecailly on 6s!

[suicideneil]

Ta-da. Not as good as I had hoped, alas, alot of action happended off camera, or I simply couldnt keep the truck in shot (narrow field of view). I did get some good stuff though, should demonstrate the power, and some of the speed too; most of what you see on tape happens at 1/4 throttle....

well done there neil, is your monster ok? i see you have more wheelies to worry about with that setup vs. the hvmaxx, shouldve had a body on lol

[GorillaMaxx360]

hey suicideneil could you take some measurments for me i plan on building a esc clamp.

measurments

1.)What guage wire does the esc come with?
2.)What are the approximate dimensions of the ESC (height, length, width)?
3.)Lastly, how big is the cooling fan circle in the top of the ESC (diameter)?

thanks

[TDC57]

Nice Neil.. Glad to see you with some power!! Your Truck is running great!..

Looking Good......

Hey Neil,
Very nice build, I have been reading your updates for some time. I would really like to know how the Losi shocks are performing for you. Based on your truck I am thinking of running them on my 3905 Maxx, but would like your input. My truck is no where near as modified, so I am thinking I might be able to shed some weight and only use 4 shocks. I would like to hear your thoughts.
Thanks

[suicideneil]

They've performed just great so far, though I do only have a limited number of runs with them, so more testing is needed really. The best way to think of them is like the much loved pro-line powerstrokes- more or less the same thing being 1/8scale shocks, very very smooth and durable. 4 shocks would be fine for a lighter truck- I did use 4 for a few runs but it wasnt quite enough to keep my 13lb truck planted well. With a more normal suspension setup (upright shocks vs laid down) I think you will just love them over traxxas stock items, or bigbores even.

[suicideneil]

And now I have some more:





I made a much neater job this time around- using glue instead of tape to hold the cells together before shrinkwrapping them is a much better idea. I will probably go back and tidyup my first pair since I have plenty of the nice clear wrap left, cant stand untidy looking electronics...

hey neil, hows the weather over there? nice pack job, and hows the cheapy 9xl holding up?

[suicideneil]

Weather was hot and stuffy today- would have been nice to go to the park with the truck, but I decided to do some shopping and build the new A123 packs instead. That way if the weather stays nice for saturday, I will have even more batteries to use and get in some more 9XL testing, maybe experiment with gearing a bit more since the A123s dont heatup like my cheapo lipos did-, more headroom for gearing without fear of killing batts.