So I've begun rebuilding a Fighter Buggy RX from my childhood...

[Nitomor 2122]

Haha, cheers.

For the pictures, you just need to click the links, they're publicly shared..

I know I clicked them but it ruins the flow of what you're writing and you can't refer to the other pics simultaneously which makes hard work of reading when they're not embedded, there is a much better way with photobucket and it is free, just a suggestion to make your posts more enjoyable.

As XV says, the WT01 is a great base for tinkering with. They kind of get under your skin

[Lawsy 27]

I know I clicked them but it ruins the flow of what you're writing and you can't refer to the other pics simultaneously which makes hard work of reading when they're not embedded, there is a much better way with photobucket and it is free, just a suggestion to make your posts more enjoyable.

As XV says, the WT01 is a great base for tinkering with. They kind of get under your skin

I just read your 4X4X4 build thread, and that is a truly excellent job you've done.

I use middle click for almost all links and often have my fingers to the left of my keyboard at rest, allowing me to quickly alt+tab and alt+shift+tab to get back and forth between tabs. If I want to compare, I just drag a tab over to one of the other monitors. You're just being difficult The real issue is the quite frankly appalling lack of image hosting compatibility - something I've never run into anywhere else, and I've been a member of that many forum communities over the last two decades that I've lost count. A number of modern image hosting platforms truncate the extension (like ".jpg") from the URL, and this seems to be the issue (an absurd issue to have).

Ranting aside, I think I have an idea that would allow DT03 lower suspension arms to be utilised by the standard DT01 chassis.

Thanks to the images from Nobbi1977, I can see that the DT03 suspensions arms are the same width at the chassis (prior to the pivot) as the DT01 arms. As most of you know, unlike many other suspensions arms that use some form of "pin" to fix the suspension arm to the chassis while allowing rotation, the DT01 has cylindrical lugs moulded into the plastic which insert into the chassis instead.

It appears there is enough clearance in this area that a "crankshaft" shaped adaptor of some kind could be used (two being required, or a single design held together to prevent rotation at the "main bearing" part of the "crankshaft" - hopefully that makes sense).

I really do think this is possible. Not only would it allow for an increased amount of adjustment (just remake the adaptor(s) for whatever length and angle required), but it would be reversible (for whatever reason). Most of my modifications so far are reversible, I've not yet reinforced the chassis, nor drilled the damper pistons (yet), so other than the machine screws into the top rear damper mounts to allow for the ball collars, it's all original. If I can get DT03 suspension arms to fit without any other parts (apart from C hubs), then I could have multi-link geometry for single digit dollars, and that would be excellent!

[Lawsy 27]

From the images and the DT03 manual, it looks as though Tamiya in their infinite wisdom have put front and rear suspension arms on the same parts tree. Specifically, front and rear "upper arms" are the "E parts" tree, with the lower arms being on the "D parts" tree. If so, this is no longer financially feasible... After shipping, I'd be up for around $50 (both D and E parts + B parts that would be special order) for something equivalent to putting make-up on a pig - in the end it's still just a DT01 with a moronically designed, unsprung rear end...

But I've got some ideas that might not require any parts from any other car - the only issue is it isn't reversible.

When looking through the DT01 double wishbone thread, TA-marks solution seemed to require too many bits from other models that would be expensive to source if you wanted only those bits. I also didn't want to hack up the front end, because if I get it wrong, I'm up for new suspension arms (and that would be really annoying), as well as all of those expensive bits again...

However, there is a hack job that I'm considering... Have a look at all of the following images in order, some of you might "click" with the first one...

IT IS NOT IN ANY WAY PRETTY. But it uses nothing but bits that I already have, should be quite easy (I think, the hardest part will be the first cut, and not because its difficult, but because it's the point of no return - I'll take about an hour psyching myself up for it I think), and I'm pretty sure it it will be quite strong.

Again, this is not going to look pretty - but it should work.

I can't really explain what I'm thinking of doing here because there isn't a name for all the bits yet. Well I could but it would be difficult and hard to follow. Central-lower-damper-mount-C-hub-pivot? Yeah... CLDMCHP for short... Yeeahhhh, no.... I think the last image (my epic MS Paint arrangement) explains adequately what I'm thinking (plus the second last image for the control link using some M4 threaded rod).

Anyone feel free to name the bits if you think you get what I'm trying to do.

Ye, nay?

[Lawsy 27]

I purchased some pre mounted rear dirt hawgs, and loose fronts that I mounted on a new set of rim's, and it's great. Ultimate grip is not as high as the road tyres, but this seems a lot more fun.

Still enough to barrel roll if you turn in at speed, so care needs to be taken, but lowering the center of gravity should fix that.

Dirt Hawgs definitely get a thumbs up from me.

[Lawsy 27]

The SkyRC leopard 3930kv brushless combo was waiting for me when I returned home. Soldered a dean's connector on the battery, bolted the motor in (with the 17T), set max punch control, timing for efficiency, and a 6v cutoff. All reasonable values considering how light the DT01 is.

Acceleration was possibly worse than the sports tuned. Didn't continue, just turned it straight back and set punch control to 40% instead of 100%.

Nailed it again, thinking I was going to get some speed... Nope.

Maybe 10% quicker than the sports tuned, while acceleration was really nothing to write home about.

My timing settings, that's it. There must be a huge difference between 0 and 16 degrees. Punch control right off now, and ran the throttle calibration to be sure.

Now I'm nervously excited and optimistic that a little mayhem is about to be unleashed.

This was not to be, it was maybe 20% faster.

Suffice to say, I am bitterly disappointed.

I've now read so many people's experiences to know that a sports tuned at a nominal 7.2v, should be rated the equivalent of about a 2250kv motor if you've got a good one (which I strongly believe I have).

This brushless thing should draw 42 amps flat out, and hit north of 26000RPM in such a light car, even with only NiMh... I'm in no way getting even close to this.

Acceleration is underwhelming at best (I was expecting either wheel spin, or a tiny bit of front end lift. Nope...), and to top it all off, after only half a pack, the motor is hot enough than you wouldn't want to touch it.

Have I been sold a fake? I've watched guys with the 3300kv version, installed in heavy cars and running only 2s LiPo, and they are quick. There's a video of one in a DT02 or 3 (can't remember), with only 7.2v NiMh.

ALL of those look like they have much better acceleration, and are clearly faster than this...

[Lawsy 27]

I ran another pack through it and this time around it seemed to be a little quicker. Still nothing like I was expecting. Maybe my expectations were too high?

I'm using a 3500mAh battery (and although cheap, run times and charge times certainly suggest its capacity is north of 3000mAh), so I would think it could somewhat handle over 30amps being drawn (only 10c). Then again, maybe not?

Or maybe this cheaper pack can handle the current draw, but at the cost of voltage? That would certainly dampen things.

[Snappy1 966]

You aren't running a lipo are you?

[Lawsy 27]

No, which is also why I didn't expect the same sort of "flip over" performance I've seen from this same motor in similar vehicles (gearing/weight) on quality 2s or 8.4v Nimh.

But I did expect it to be significantly better. After all, I've basically gone to a motor which has about 70% more kv potential than the Sports Tuned (and that's using quite optimistic figures, half way to the Super Stock RZ 23T motor)...

Even if it is slow to get there, on a slight downhill section it should achieve a semi-decent speed (around 50km/h). It didn't look like I was breaking much over 40...

So maybe this battery was on it's limit with the Sports Tuned, but demanding more from it is dropping the voltage by too much, and therefore my total power is significantly reduced. The battery just didn't feel hot enough though (then again, maybe even a Sports Tuned was asking more than it could give, so it's possible I was already beyond the limit - asking more from it might result in only a minor increase in internal resistance/voltage drop, and therefore heat at this point).

Tomorrow I'll be back on the driveway at home which involves a lot more heavy acceleration and braking to have any fun on. The battery will have a 98% charge (stopping it now), and I'll give it a 20 minute top up before I run and see how temps feel after that.

[GregM 1109]

Speaking from similar experiences with my Mad Bull, I highly recommend you trying a 7.4V LiPo battery pack. A simple 7.2V NiMH or NiCd won't cut it, since it won't give you the desired top speed, acceleration, and will feel "half drained" far sooner than a LiPo, since it can't keep it's voltage constant over runtime, under load.

If shopping for suitable LiPo stickpacks, make sure they don't exceed 134 mm in length, otherwise you'll get in trouble closing the battery stopper. This thread should help you: http://www.tamiyaclub.com/forum/index.php?showtopic=67706

[Lawsy 27]

Thanks mate. Yeah I read that one a few times now, it's just a matter of cost...

EDIT. I also recall, Greg, you mentioning in several older threads that there was an appreciable performance difference from a quality NiMh pack and lipo, and the peak current draw from that Carson is about 7-10 amps lower...

So of course this will suck balls on my cheap eBay NiMh stick. I was just hopeful that I could get away with it, or I just didn't realise the extent to which it would suck. Either way, I want more speed...

I'm very tempted to make my own modular pack, giving me the option to run 8.4 or 9.6v... Much cheaper than a new charger, the LiPo pack that will fit, lipo fire bags and balancing hassles...

[Lawsy 27]

Right so - I'm confident that my issues is indeed the battery.

Long story short, I watched some direct battery comparison videos (instead of just the random videos I'd seen previously), and yeah there's a big difference alright. I thought the kids on the Traxxas forums were exaggerating in some posts, stating that "It was like I was running a motor with five less turns!", however in other posts some even suggest, "Matched 6 cell racing NiMh packs are faster than 2s LiPo". And then over here, the adults say, "Yes, there is a noticeable difference". So my opinion was formed based on the middle ground, much closer to what I thought "...a noticeable difference..." would be, only with more consistent power for the duration of each charge.

But all of the videos I can find suggest the Traxxas kids were spot on the money in this respect, and the adult translation over here is actually: "Flying bat crap! This thing screams now!" These Tamiya forums are a bit too civilised it seems compared with reality.

This was far more telling when one of the first videos I came across showed tests comparing top speeds between a quality 7.2V NiMh and generic 2s LiPo, all else being equal and from a full charge. This resulted in a 33% increase in top speed. That is not a little impressive, that's awesome, and more than I feel is missing from my upgrade. Plus, I'm using a cheap ebay special battery, so even if I'm conservative and expect only a 25% gain from upgrading to LiPo, that would take me from, this improvement in speed simply won't cause enough accidents for my liking, to, Weeeee, carnage!

But this will mean I need to buy a new charger, fireproof bag, and connectors, on top of the battery itself.

So hooray; let's go spend the value of my entire rebuild budget to upgrade the battery. FFFFFFFFFFFFffffffffff...

I'm really not happy about the situation, as a whole...

EDIT: Just to clarify something: The comparisons I am discussing above - with the LiPo battery providing a significant improvement in performance compared with NiMh (6 or 7 cells) - were those in which the motors could place enough demand on the battery that the LiPo's higher current potential (with a lower voltage drop) could be taken advantage of. I am fully aware that if I were to upgrade to LiPo and run the Sports Tuned, the performance increase would likely not be more than 10%, since my existing battery isn't completely falling over itself with the load presented by the this lowly 27% motor, and it holds on (just). With the 10T installed, the battery is struggling at 50-60% throttle, and this is actually quite noticeable. Both ESC's are quite nice and linear, feeling similar in their proportional response until the 10T hits 50 - 60%. At the same point, the Sports Tuned still keeps increasing in speed in predictably smaller amounts with each increase in the throttle (until about 90% where I can only tell the difference when if I go straight to 100%). With the 10T, everything feels about the same until around 50-60%, though slightly faster and possibly a bit smoother. However, at this point increasing the demand only results in an exponentially reducing increase in speed. Going from what feels like 85% to 100% is barely noticed, and I'm now fairly sure that the battery is drowning in its own filth at this stage, such is the punishment being placed upon it.

[Nobbi1977 1793]

I found a silver can on LiPo to be like a sports tuned on NIMh. It just runs harder for longer.

Where abouts are you? Maybe someone can meet up and lend you a LiPo for an hour

[Lawsy 27]

I found a silver can on LiPo to be like a sports tuned on NIMh. It just runs harder for longer.

Where abouts are you? Maybe someone can meet up and lend you a LiPo for an hour

Yeah, Nobbi, this makes perfect sense as well.

I found the battery discharge data from Access of rcuniverse, and if we assume anything from 10 - 25 amps are drawn at top speed (depending on the cars gearing and parasitic losses, I can't actually find any real data from an actual data logger for a stock silvercan or a similar brushless setup), then the voltage from even a decent Nimh battery would be anywhere from 0.4 - 0.6 volts lower than a comparable 2s lipo. Using the top speed calculator, that's about 10-15% depending on which specs you use, or at least in the ball park of a Sports Tuned compared with an unmolested Silvercan.

But when I watch videos of this exact motor (Leopard 3930kv 10T) in anything from far heavier truggies, to similar weight buggies with taller gearing, the rate of acceleration and top speeds are certainly higher than what I'm achieving, and I just don't know if a battery upgrade is going to provide the level of improvement to be on par with that appears to be normal for this motor in similar weight/geared vehicles...

But we'll find out soon enough - an FT680 (same as the Traxxas EZ peak plus) is on its way, and so is a 4000mAh 30C 2S Lipo...

I'll know if this motor is a dud by the middle of next week....

[GregM 1109]

Please let us know how the Lipo holds up in comparison.

By the way, do you mean Traxxas, not Traxxis?

Cheers, GregM

[Lawsy 27]

Please let us know how the Lipo holds up in comparison.

By the way, do you mean Traxxas, not Traxxis?

Cheers, GregM

Will do, and what Traxxis, where?

[Lawsy 27]

This afternoon I had the stupid idea of putting my cell phone (comparatively expensive) inside the shell, which can only be fixed by the front split pin, then laughed at how moronic this idea was and how expensive it would be if I crashed and had to buy a new one.

So the GPS data showed........

Pass 1: 42km/h - backed off early, was just seeing if it would work

Pass 2: 43km/h - shorter run, about a 1:100 slope (downhill, very mild), checking repeatability

Pass 3: 44km/h - longest run, easing up to speed, full throttle before the last section which is dropping with about a 1:20 gradient (to try and unload the motor as much as possible and see if it would keep accelerating, or hit minimum load state and hold).

I think my attempt was a success. As the downhill gradient increased after already hitting Vmax before it, you could clearly hear the otherwise very noisy pinion, as well as the sound of the motor itself, significantly reduce in volume to just above that of coasting but without any increase in speed. The tyre noise was actually louder at this point! So for whatever voltage there was available, this was highest RPM that was going to be achieved for this run.

Some maths is needed to back calculate the physical parameters required for this speed to be possible.

But who can be bothered - top speed calculator webpage, please sir!

Differential Ratio: 2.88235

Spur Tooth Count: 54

Pinion Tooth Count: 17

Total Voltage: 5.85

Motor KV: 3930

Tire Diameter (inches): 3.622

Tire Ballooning (inches): 0.35

Motor Current Draw: 40

Motor Coil Resistance: 0.0155

Total Ratio: 9.1557 : 1

Tire Circumference (inches): 13.58 inches (344.88 mm)

Total Motor Speed: 20553.9 RPM

Vehicle Speed: 28.87 mph (46.37 km/h)

Effective KV Value: 3513.49

Final Power: 234 watts (0.3 HP)

40-43 (or 46km/h less 5-10% for parasitic losses), is about what I would expect to achieve on a perfectly flat run with the current setup, without any fancy re-peaking of the battery before going for Vmax. I'm surprised how low the voltage needed to be in order to achieve values that represent reality. Furthermore, the tyres balloon nearly a half inch when 80% throttle is applied, free wheeling. However, one wheel seems airtight and balloons only half as much as the other (I know I know, I need to drill tiny vents in the rim), so I figured using half of the observable maximum ballooning was more accurate (and this has a substantial affect on speed, clearly noticeable when I run the street tyres that physically can't balloon as much. Even with the 19t pinion, you could clearly see it didn't "sit up" on the rears as much as with the dirt hawgs). It's also possible that the slight ballooning difference causes some differential action to help account for the difference in rotational speed, and this would introduce unnecessary parasitic loss - I could be loosing something substantial here, or it could be negligible - I won't know until I vent the wheels to eliminate this as a potential loss.

If I use the 9C load (from 4500mAh) value of 7 volts, representing the worst case lipo test data provided by Access, then things begin to look far better, and back to what I was actually assuming could be achieved (except I thought this might be possible with the Nimh pack - ha!).

Differential Ratio: 2.88235

Spur Tooth Count: 54

Pinion Tooth Count: 17

Total Voltage: 7

Motor KV: 3930

Tire Diameter (inches): 3.622

Tire Ballooning (inches): 0.35

Motor Current Draw: 35

Motor Coil Resistance: 0.0155

Spur/Pinion Ratio: 3.18 : 1

Total Ratio: 9.1557 : 1

Tire Circumference (inches): 13.58 inches (344.88 mm)

Total Motor Speed: 25377.98 RPM

Vehicle Speed: 35.64 mph (57.25 km/h)

Effective KV Value: 3625.43

Final Power: 245 watts (0.3 HP)

I also entered only 35 amps as the current drawn, though I suspect this is excessive considering the car will be running down a slight slope, making this speed not only easier to achieve, but at a lower current draw as well (the downhill should negate parasitic losses, making this calculation more accurate - that's my guess anyway).

Honestly, I never thought this NiMh pack was such an under-performer, and since I cannot fault the mathematics or electrical principles behind this calculator (from what I remember at least), I find it difficult to argue differently.

If lipo is all it's cracked up to be, I might even push beyond 70km/h with a fresh charge, vented wheels to maximise ballooning, and using the 19t pinion again (just for a few speed runs). If so, that would be a level of stupidity for this rickety old chassis that I could find acceptable... Then I really need to mod the front end to get rid of all this camber and bump steer, and add back the 150grams of weight I will be saving from the lipo upgrade, only to the underside of the chassis (the aluminium/sikaflex idea). This should hopefully sort out a number of handling issues and allow me to take corners with some speed on board again, because the dirt hawgs simply have too much grip, and with the additional ride height, she just rolls over if you even think about turning with any speed on board...

I will keep you posted if anything interesting happens (spontaneous combustion, perhaps?)

[Lawsy 27]

I'm also still waiting on the threaded rod from China, which is partly why I have not gone ahead with any suspension modifications yet.

I've also been thinking about the rear suspension. I think I might go down the path of that Frankenstein Mad Bull that, other than the youtube video, no one seems to know anything about.

This means: -

• Standard damper top mount
  
• Custom lowered damper mount - but much lower (just above the lower screw holding the gearbox together)
  
• No heavy Meccano/nuts/bolts negatively effecting the centre of gravity
  

I also believe that bump steer is a significant secondary contributor to the barrel rolling.

Imagine the car coasting (or trail braking) into a corner. As steering input is applied, the weight transfers to the front outside wheel compressing the suspension, causing bump steer which further increases the weight transfer, causing more bump steer. Only this is happening in in a single smooth action due to a critical imbalance in the forces and moments involved, and so it rolls over in an embarrassing crash. It's certainly annoying when this happens at the top of the driveway, and someone is trying to use your driveway to perform a U-turn. Playing with fire comes to mind.

Bump steer, what a prick.

[Lawsy 27]

My new battery charger just arrived. Sure enough, it looks exactly like the Traxxas EZ peak plus.

This post is going to simply involve random notes I feel like taking as I test it out, since it's charging on my desk as I work. How a battery charger is "fun to play with", I've no idea, but it is because its new... So this post could be super boring, and I would recommend you just ignore it.

I'm discharging this Nimh pack at 1.4A. I will then auto-charge with a 2.5A current limit. Considering this is a low quality pack, I figure that even a 1C charge rate is a little optimistic... However, if it accepts over 3000mAh, I'll be fairly happy (not that it matters after the lipo arrives).

Immediately the resting voltage of 7.58V dropped, and stabilised at 7.22V after only 30 seconds @ 1.4A. So for the sake of comparison, I stopped the discharge for 5 minutes, and back up the voltage went to over 7.5V (7.52 or something).

Does that seem like a higher than normal voltage drop to anyone? Now and then I looked over to see how it was doing.

30 minutes, 6.95V and 665mAh drawn - I've no idea if that's reasonable or not.

55 minutes, 6.52V, 1239mAh - hmmm - definitely more charge than I first thought remained in this pack

63.30, 6.2V, 1436mAh, target reached

After 5 minutes of rest the voltage recovered to 6.82V.

I started another discharge, and took it down another 150mAh at 6.15V.

After 10 minutes at rest, voltage recovered to 6.77V.

I'm looking at the data posted by Access of rcuniverse again, and for comparison, there was a reduction of 0.9V between the two 4500mAh Nimh packs, one was loaded to 9C, and other 3C. That's an increase of 27 amps. I don't know what to make of it, other than it seems this battery of mine has terrible discharge performance...

To make this even more strange, its taking current like a boss during this recharge.

3400mAh @9.34V, still accepting 2.5A

3600mAh @ 9.5V! - still feeding 2.5A - does this charger simply pummel the battery at maximum current until it delta peaks? Doesn't it back off at a certain point, or is that only in lipo mode?

I stopped the charge and restarted it with 1.5A instead, 9.5V just seems excessive.

3800mAh @ 9.28V/1.5A - only now is it beginning to feel warmer.

3900 @ 9.15V when delta peak was detected.

For what is a terrible battery with regards to its discharge performance, it sure chopped some amps!

Thus ends the boring post about my new charger and my strange battery.

[Lawsy 27]

I hit the battery with another 125mAh (at 2 amps), then immediately ran it down the street.

Pass 1: 46km/h - car coming, didn't hit the slope
Pass 2: 47km/h! - Full, clean run, clearly picking up a fraction of speed and holding when mid way down the slope.

Although I still haven't vented the wheels, I'm certain that 47km/h is close to the maximum this combination has to offer. Maybe tomorrow it will hit 48, as I'll go drill a couple of holes in a minute so it's got no excuse.

Ok. Holes drilled, we'll see how it goes tomorrow.

Hmmm, this charge is heating the battery up significantly more than after any previous charge, it's actually quite hot.
It's certainly still taking charge, however, but I'm pulling the plug.

How hot should Nimh get after about a 2/3C of 3500mAh (2amp) charge? Right now it feels about as hot as after a really hard run of at least 3/4 of its capacity, and it didn't look like it was going to stop charging any time soon...

[Lawsy 27]

Having both rear wheels vented improved stability, but a couple of aborted runs knocked the edge off the voltage, so she couldn't crack more that 47km/h today.

Might be time to change the pinion...

[Lawsy 27]

The 19 tooth pinion, maximum of 32° motor advance, and a re-peaked battery resulted in only 50km/h. Mathematically this should be 52.5, since v = 47/17*19.

It's a bit sad really.

Either I've hit a critical load where there simply isn't enough motor torque per rpm per volt to go any quicker (which Lipo should fix), or I'm hitting a point where parasitic losses are becoming exponentially larger and power alone is not the limiting factor. Both axles are a little bent now, and even though the vibration is quite minor, I suspect this is not helping my cause...

I guess the only thing I can do is try and balance the wheels as best I can until there is minimal vibration at maximum RPM. I'll get the wheels "almost balanced", and then rotate them to each of the 6 positions on the hex hub, and see if this helps.

I'm also thinking that, potentially, the higher damper mounting position may not be an improvement with the current tyres due to the higher centre of gravity (from the relatively heavy Meccano sitting so high). This will only be worse when I use a far lighter LiPo battery, increasing the centre of gravity further.

And as I typed the above, my threaded rod arrived, so maybe over the weekend I can mock up a lower damper mounting adaptor and see what we can achieve, which should allow me to eliminate the Meccano entirely and have a similar setup to that German MadBull shown on youtube, which truly does seem to handle quite well, all things considered.

In other news, the Lipo battery was delivered on Monday.

Sure enough, it was a 2S, 4000mAh, 30C LiPo with the dimensions in the listing - except what was listed was a rounded edge, "stick pack" type hard case that we all know and love, and what was delivered was a typical rectangular prism hard case with detachable leads... It's posted back, with another on the way, hopefully they don't stuff it up twice.

[GregM 1109]

That pinion noise makes me wonder if the motor axle is bent, the motor screws are bent, or the gearbox case is either warped or broken at the screw mounts. I managed to break a Hornet gearbox case by overtightening the scews.

If you are able to, please post more gearbox pics and maybe upload a video to youtube demonstrating the noise.

[Lawsy 27]

Thanks Greg, I hadn't thought of those possibilities.

I've dumped all the images into a single album photo bucket .... But out of protest, I'm linking you to thumbnails so if you want details you have to annoyingly click on the images still... Actually its because I didn't resize them properly and the quality isn't good enough for the size of the image, and I'm only on a quick break from work so I am certainly not about to do that here...

Here's what I've checked

• Motor Axle; its straighter than a... Well I'll leave the inappropriate joke aside, but it's very straight.
• Motor screws; seem fine, and I can't see how I could have bent them. It's more likely that I may not have torqued them down evenly (I'm concerned I will strip the thread in the aluminium). I've torqued them carefully now though, a little tighter than before. Both felt strong without any sensation of stripping. Phew!
• Gearbox screws. The lowest position is currently a machine thread, and the best of the three. Top screw; somewhat stripped - still holds strong. Rear Screw; feels as though it could strip - but also holds well.

Maybe that first thread starting to strip on the two screws allows just enough flex under load for things to get a bit noisy?

I'm becoming more inclined to think that what I'm hearing is normal, or at least, it is now. With the Sport Tuned and the 19T, maybe I had not tightened the motor bolts correctly and this is why it was so much louder. With the 17t and the brushless, it's louder than the aluminium, certainly, but doesn't compare with noise when I had the 19T installed with the Sports Tuned.

Or it could simply be that the counter gear has now been "run in" by the steel pinion, like piston rings in a new motor, they perform better after a period of use for everything to "seat better" and accommodate for the slight tolerance variation of each cylinder.

Finally, I performed another test to help confirm no-load operation, hopefully ruling out the possibility of static issues like bent motor shaft, stripping, or bearing issues.

If trim the throttle to achieve the lowest RPM possible, but give the throttle a tiny "flick", it will reach this almost completely silent minimum load state (and for for quite a few seconds, so the bearings are fine it seems).

Hit full power and that "rip cord" sound's, as the motor loads up to overcome the slightly increased inertial load of the Pro-Line wheels, and quickly turns into a tyre-ballooning, air-slapping symphony. At max RPM, everything sounds normal within the gearbox. There are no cyclic noises, grinding noises, or increasing/decreasing noises that could indicate a less obvious problem, like the gear moving axially along a shaft outside of its normal bounds (if say, the gear case was not flush and there was 0.5mm more free play on the counter gear).

In other news.

Received the wrong Lipo again today...

So I'm going to just charge it, strap it down and at least see once and for all what the deal is... Then send it back again.

[Lawsy 27]

Ummm, right so.

I think I might be able to confirm the battery as my speed issue.... Strapped the Lipo lengthways, making the centre of gravity an utter joy to behold... It was terrible. But whatever, because LiPo.

Attempt 1: If you scaled up what this little Fighter Buggy just did to 1:1, then we just left two of the thickest, blackest, smokiest double lines from 0 until about, oh I don't know, 500km/h, on the way to some stupid speed.. I didn't dare strap my phone on to measure it.

Attempt 2. Knowing traction is my limiting factor, I gave it a good stab. Flip...

Attempt 3: Ease on the power, accelerating hard, hit a small bump just before full throttle, flip.

Attempt 4: Fish tails, brake, barrel roll but back onto the wheels, stab the power to get some momentum - flip - LANDED IT! Try again, flip. Didn't make this one, instead we had a big wing cracking impact. Bugga!

Attempt 5: Stopped being a complete moron, and enjoyed 10 minutes of wheelie popping, rear tyre destroying speed, before calling it a day as I was getting hot (and so was the motor).

After one of the speed runs before bringing it in, I went a little too far down the street, turned around, and started back at 50% throttle. Right then, a van came around the corner behind it doing about 45-50km/h. Oh crap!

At this point I have no sight lines to a safe parking spot (about 120m away) and I'm already at 70% speed! I basically had no choice but to speed up and beat it up the hill, mash the brakes in anger and nip into my driveway, or risk relying on the van driver to brake and not run it over if my attempt to pull into a safe spot turned into a barrel roll onto the roof (which was highly likely based on the dozen or so times this had already occurred)...

Except the thing launched up the hill at such a pace that I had enough time to gradually slow down over about 35 metres, take a nice gradual turn back to my position and stop with at least 3 seconds to spare. The car was safely stopped and the van continued on its merry way without even having to lift, at about 50 - 55km/h. I would guess the buggy went over 60km/h. I want to say more, though, since compared to normal it was going just shy of ten thousand.

Or 65- 70, but mathematically I know that's probably not the case, so let's just call it a bit over 60.

So you reckon the battery was the issue then? Maybe we should call the old battery an anchor instead...

[Snappy1 966]

Once you go lipo.....lol

I have a DT-01 Rookie Rabbit, I have always thought that the gearbox was noisy, I added bearings, changed gears and pinion and it's the same, maybe normal for model?