nowinaminute

Next up, the motor and mount area. This is one of the places I don't trust entirely, just because the mount sort of has an open side and relies on the gear case moulding to make a tight seal, I think this could have been a potential source of ingress, especially bearing in mind I didn't add any grease as a precaution the first time around.

So I've been having a great time with my TD at the beach for the past week or so but on Thursday, the pinion and spur gave up and stripped out so it's time to see what went wrong. The most obvious guess is sand ingress, and I know I didn't take my usual precaution of running a bead of grease around the gearbox cases or checking for any obvious openings, so that's definitely a strong suspect. But I also know I had a questionable alloy pinion in there combined with brushless power and sand paddle tyres so there was a lot of power and a lot of drag on the drive train, so that could also be at least part of the issue. I now have my new gear bag and a decent RW steel pinion so it's time to get stuck in! General view of the work area: Rear end removed: This is a good example of why I like to run on nice dry dunes rather than the damp or wet sand. My first 3 runs were on dry sand and the car was spotless after a shake off. The last run was on the slightly damper sand on the beach and it just gets everywhere and stays there! Not as bad as running on the really wet stuff, but it certainly illustrates how a beach run can be pretty much zero cleanup or a fair amount of effort depending on the type of sand! I've also noticed quite windy days in the summer are good as parts of the main beach will tend to dry off completely and little ripples of dry sand will form. Anyways, I still like to run on the damp stuff now and then but you have to be willing to put the time in afterwards to clean it all off and maybe rub some oil or wd40 into the parts that can rust. First off was the prop joint cover and there's a lot of sand and crap in here! Interestingly, there was more sand here than in the main gearbox, so possible a small breach in the cover going on here. I'll check it on reassembly plus add the usual bead of grease. The gears are a little roughed up but I think I will reuse them as they have plenty of meat left and maybe some of that awful flashing from the factory has been ground down 🤣

Looks absolutely fantastic!

Yesterday I took my Thunder Dragon out for another beach run and the pinion/spur gave out! I think it's a combination of 2 main things. Firstly using a cheapo alloy pinion and secondly, a little sand ingress. Combined with brushless power and sand paddles that give some pretty decent bite even on soft sand! To be honest, I kind of skipped my usual check for dirt proofing during initial assembly so that's probably a factor. I never thought to ask back then if there's any particular areas of concern in terms of dirt/sand getting in. I'm using a sealed can brushless motor so it's nothing getting in through the motor vents. I usually put a bead of grease around the gearbox halves but I have a feeling I didn't this time. I'm also not sure how well sealed the area around the metal motor mount is etc. Anyways, I have a nice hardened steel pinion to go in and a gear bag on the way so I can replace the spur. Once I've stripped it down and given it a good clean, I'll check for any obvious weak points and address as necessary and then reassemble with strategically placed grease to form a barrier/trap, which has worked a treat on other stuff I run at the beach.

....just remember the polarity when you pop them back in............. ........ ......... In other news, the Hobby King X-car 120a can sustain a brief period of reversed polarity and still work. The latter statement is not related to the former........I swear......

Great fun! It's twitchier than ever with the paddles and brushless, virtually uncontrollable on-road lol. But on the sand it all comes together nicely and works pretty well! It is indeed South Wales.

Not pretty but it will do! I could keep working at tidying it up but it seems pointless really, it will get all scuffed up in there after a few beach runs, anyway. I'll just get a new chassis if I ever sell it or want to make it look pretty again. I was a bit worried about the pole connectors on my hard case lipos fouling the battery retainers but if you take them off and then insert the battery, there is room for them to go back on! So that's about it! Hello boredom limited runtime!

Based on the small amount of plastic needing to go, I just used a hacksaw blade and went at it lol. Very easy to do. Just used the tops and sides of the slots as a guide to start sawing into the material. Bit rough and ready but it does the job. I used a file to tidy it up a little and a round file in the corners to take the right angle away. I might add a couple of bits of felt tape inside the chassis to prevent any chafing, especially on sand runs. But anyways, now I can run it until I get fed up and not until the batteries run out! I'll add a couple of pics shortly.

The more I look at it, the more it seems like it will just be a simple hacksaw job? Just need to try and make it relatively neat...

Finally

Anyone done this? Straight forward? Took my TD out for a nice beach run yesterday with sand paddles and a 3900KV brushless and it ate batteries! My two rounded 4000mah 2s lipos didn't last too long! I could either buy a couple more rounded packs (not ideal in the current UK financial climate, the less money I spend now, the less chance of freezing to death this winter ) OR convert the chassis to fit square packs as well. I have 2x 8000mah and 2x 5200mah hard case packs. I'm pretty sure those, along with the 2 4000mah packs, would give sufficient run time! So I'm just wondering if anyone has done this modification and has any tips/advice before I start hacking away? Cheers, guys!

Well. Looks like the ar5e fell out of that!

Some old video that's too good to keep hidden in the vault!

Any news on this thing? Driving experiences?

I had a set of normal decals for my Lunchbox. Quality is subjective I suppose but I'll give some pros and cons. Pros: Nice artwork Pre cut Nice colour and overall print quality. Cons: Blacks in the print were poor, more like a grey, which detracted from the "punch" of the artwork. Cutting wasnt perfect with some white bits around the edges in some areas. Because of the medium used, even if you carefully trim all the excess white off, the actual cross section of the sticker is white and will show up as a white outline around the artwork on darker base colours. Adhesion could be better, smaller areas peeled off a lot at first. Hairdryer helped but didn't totally fix the issue. I would say overall they were decent but the quality of the blacks could be better and the adhesion. This was over a year ago so for all I know, those issues may have been addressed by now. I would say more suitable for a shelf queen or special occasion "fair weather" runner more than everyday use, I could see them starting to peel off and get dirt stuck under them etc quite easily.

Amazingly, all of these lipos are still in good health and working well. They haven't had TONS of use but they haven't been dormant, either. What a bargain that was!

Which is interesting because the very first time I used a forming tap on a DT-03 chassis I suffered multiple cracks/fractures. Also on an M-05 steering rack because I didn't like how tight the brass ball joints felt so I thought I'd use the tap first but it still split. Do you drill the holes at all first? I feel like not all Tamiya screw holes are made equal. The ones intended for self tappers seem a little smaller than ones Tamiya intend you to put machine screws in. And presumably using a manual hand wrench and not any kind of power tool?

It can be tricky to get an exact idea of what you're looing at. Most manufacturers of brushed motors follow the Mabuchi naming convention, or use some variation of it. Specifically, the numbers that refer to the wire diameter and number or turns. But, just like Mabuchi, they don't necessarily print the actual motor designation code on the can. They often just have meaningless batch numbers etc. You often just get something like the RPM but sometimes they don't even state at which voltage. Some of the better sellers actually give a few RPM rates per different voltages which helps but it's still preferable to know the actual specs. Sometimes if you're lucky, it will be printed on the can and visible in the advert photos, even though the advert itself doesn't actually mention it. For example, this is a 20T 390: And this one a 25T 390: And an 18T 390: And here is a 24T 380:

Definitely possible. The ST380 is 29 turns. I have 380 motors as low as 16 I think. I'd have to guess the gearing is relatively low on this buggy, though, because such a small motor with such a high RPM is likely to get pretty hot. Even the stock 40T Grasshopper motor gets red hot if you thrash it and that's with the 10t pinion.

Better is subjective, I suppose, but they are a little longer so have a little more torque and get a little less hot per given amount of work which helps. They come in a few different specs but there are 23t and 20t among others, pretty quick.

2430 is usually 2mm But 2435 and 2445 have 2.3mm so if you have one of those, the standard pinion should work. For some reason, most brushless 380 size motors (2838) have a 3.175mm shaft like a 540 and skip 2.3mm, so there's a discrepancy between the brushed and brushed version. But I did find this 380 size with a 2.3mm shaft: https://www.aliexpress.com/item/33047983063.html?spm=a2g0o.order_list.0.0.21ef1802ifvagG Brushless punch above their weight compared to brush, though, so you may find a 2435 is more than enough.

Been really tempted by this, I must admit. But I have way too many projects and hoarded "future projects" etc at the moment. Been trying to downside a bit. It's a great looking buggy and very reminiscent of days past in terms if actually have a little personality and realism. Manufactured by Thunder Tiger, I believe, so decent quality. The brushed 380 motors have a 2.3mm shaft if that helps. A cheap/easy upgrade might be a replacement 390 motor intended for the likes of a Chinese model such as WLToys A959. I think the main thing I'd be interested in after a little more power is some oil dampers. Perhaps those "HSP" style 1/16 units could be good? Ampro has used them to good effect on other small buggies such as the Grasshopper/Hornet family.