My DT-03 for fun driving and tinkering

[BuggyDad 4464]

@Kol__I'd be interested to hear how you get on if you fancy trying my brace idea out. It does require a small shell cut out but is otherwise reversable and pretty much parts bin stuff.

Brace across the chassis is 88mm of M3 bar, a nut and washer on the inside either side, about 4mm of plastic spacer and a ball nut outside each side. 

Each tower strut is 84mm of bar if using a standard kit ball Cup, with another ball nut and locknut at the tower. 

[Aerobert 2136]

On 1/13/2022 at 9:50 AM, BuggyDad said:

So here's a question... 

Why does my car leave sort of pulsed tracks like this? Could this be the non-constant angular rotation of drive shafts thing? Looks like there's one faster or higher powered part of the wheel rotation. I don't think it can be pulsing of the motor because that would be much higher frequency.

I had something similar when I was on holidays in Denmark. The car ran on the beach and at some point it started lightly to bounce. There was some sand in the tires which causes an unbalance.

[BuggyDad 4464]

1 minute ago, Aerobert said:

I had something similar when I was on holidays in Denmark. The car ran on the beach and at some point it started lightly to bounce. There was some sand in the tires which causes an unbalance.

Ah! Yeah it could be that. There was a little. These ones have neither glue nor foam and seem mostly to get away with it.

[Aerobert 2136]

Mostly I don't glue my tires either if not really necessary. And that could lead to some debris in it. And it seems that some grams are enough to cause this.

[BuggyDad 4464]

It wasn't an issue, just wondering what I was seeing. Yeah these stock rear tyres are quite tight on the wheels and also fairly hard, so generally they stay put and cause no trouble. We have others that are useless without glue, especially when you combine soft rubber, truck tyre sizes and high speeds! 

[BuggyDad 4464]

DT-03: the armoured version... 

There's not such an obvious case for the rear braces as for the front, but they should reduce the deflection of the tower in a hit a bit, so reduce the chances of a break, and a bit of triangulation isn't going to be a bad thing. The top cross bar could be replaced with just a bolt either side, but there's half a chance that bracing the two sides against each other might also share the load a little on a hit which is generally going to be to one side. The Hornet brackets might have the biggest positive effect simply as skids and something to hit first.

Side benefit - rear body clips no longer required. 

[Kol__ 3377]

Looking good mate! Almost getting a bit Madmax, but still looks a bit too classy for that! I wonder if the wing should come down a bit, what you reckon?

Not sure if this has been discussed here yet, but have you thought about a bigger front bumper? I don't know why all the modern bumpers are so tiny. My Madcap has a big ol' bumper and its great, even if it doesn't look that cool.

[BuggyDad 4464]

15 minutes ago, Kol__ said:

Looking good mate! Almost getting a bit Madmax, but still looks a bit too classy for that! I wonder if the wing should come down a bit, what you reckon?

Not sure if this has been discussed here yet, but have you thought about a bigger front bumper? I don't know why all the modern bumpers are so tiny. My Madcap has a big ol' bumper and its great, even if it doesn't look that cool.

The high wing is my trademark! 😁

It could come down a bit I guess but I have found that a soft plastic mount nicked off something else is a good method, so depends what parts I stumble upon. Funnily enough I did the other day order a cheap mount from an LC racing buggy to try out on this, but I don't know whether it'll work. Functionally, I do also wonder whether the wing as is sometimes does a job in elevating the shock tower out of harm's way when it hits the deck upside down. 

The Neo Fighter is unloved appearance-wise and I share that view as stock but with the high up knock-off Egress wing I really like it. I may be in a minority of one but I prefer this now to many Tamiya buggies!

Re front bumper, I am awaiting some carbon fibre sheet to try something out. Also some foam. It's mostly because I need to get something in front of that Capri shell but it's got the potential to work without. It will have to be a flat piece of board though, no upward curve at the front, so cosmetically I'm not sure it'll be great with the buggy shell, and it'll be stiff, which could be counterproductive functionally. The carbon was more for other stuff rather than bumper, which I think would be better made out of something with more give, but it's what I'll have... 

Yeah the scaffolding is a bit Mad Max!  

[BuggyDad 4464]

Not a great masking job. Found it particularly hard to define an edge to the windscreen which has no molded line. And the flexible white Tamiya tape lifted at its edge in places. But I think both of these issues should be disguisable with chrome lines in most spots, assuming I can do an OK job of those. 

Meanwhile, couldn't resist a quick run in the dark to try my new lights out. Enough to confirm that these tyres are plenty grippy enough to roll a bit too easily on dry tarmac. 

[Kol__ 3377]

Mate, that shell looks great!! A nice progression there. Sounds like you're learning a lot as well

Ha, the lights look badass! Any good performance wise? 

What are those tyres? Aqroshot wheels yeah?

[BuggyDad 4464]

38 minutes ago, Kol__ said:

Mate, that shell looks great!! A nice progression there. Sounds like you're learning a lot as well

Ha, the lights look badass! Any good performance wise? 

What are those tyres? Aqroshot wheels yeah?

Thanks!

The tyres and wheels are both from JC Racing. I intend to use these wheels as beach etc runners - they're cheap, have no drain holes for sand to get in and with the open design should clean easily, although I don't much like the look. This car needs black wheels. 

The lights are quite effective; I've never experienced any other rc lights so I've nothing to compare them with but they do illuminate the ground in front for a little way, they're quite bright. Like they might actually enable a bit of night time running. 18mm diameter. It feels risky cutting 2 holes this big so close together but I'm thinking of trying to fit 2 pairs of them to this shell. 

[alvinlwh 5894]

12 hours ago, BuggyDad said:

 And the flexible white Tamiya tape lifted at its edge in places. 

The white tape is not easiest to use. I find that the correct way to use them is to bend on the inside curve and stretch on the outside curve. Also, they do not resist the force of spray cans that well. Using yellow tape and cutting is still, TBH the best. I believe you are doing that shell on the outside right? Should just use yellow tape and cut. 

[BuggyDad 4464]

3 minutes ago, alvinlwh said:

The white tape is not easiest to use. I find that the correct way to use them is to bend on the inside curve and stretch on the outside curve. Also, they do not resist the force of spray cans that well. Using yellow tape and cutting is still, TBH the best. I believe you are doing that shell on the outside right? Should just use yellow tape and cut. 

Yeah I thought along the way that I should next time try using normal tape and cutting, but I wasn't sure. The white tape conforms but it maintains its stretchiness so it wants to return to shape. No issue on gentle bends but tends to want to lift on tighter inside bends. I had mostly realised this though, so only a couple of those spots and they're small. Where I succumbed to the temptation to try to get away with it just that little bit. Generally it was ok, and it left a clean line, so I can see it being useful too. Other than that I found the Tamiya yellow tape and wide blue 3m tape both to be excellent at their respective jobs. Lot of tape required when you're painting a small bit of a 1/8 shell! 

I think my bigger mistakes were in ending with a sharp corner from where tapes cross. Like that headlight detail right in the foreground. Should've cut that but I feared a bit both getting the line wrong freehand and damaging the existing paint with my knife. I could alternatively have brush painted the black on grille and lights, but I fancied the smooth finish of spray. 

The other issue I had is finding a way to hold the shell in the right position to work on it comfortably and patiently. Never got satisfied with that.

[BuggyDad 4464]

On the vinyl roof I'm a bit torn now. I really want to do the vinyl roof because it's what these cars are for me. But I know looking at the shell it doesn't really suit, because although this shell has the grille and bonnet of the old cars it has the all round aesthetic of a wider stanced muscular coupe that feels later. However, I also didn't properly spray the roof orange, because the plan was to go over it.

So my plan remains to do the vinyl roof and detail chrome around with the acrylic pen, even though I think it could make the thing worse. 

[alvinlwh 5894]

9 minutes ago, BuggyDad said:

The white tape conforms but it maintains its stretchiness so it wants to return to shape. No issue on gentle bends but tends to want to lift on tighter inside bends.

I only learnt how to use the white tape recently as it is a newish product. Previously, I have a selection of different width yellow tape for this purpose. Some people actually cut yellow tape to 1mm strips to use on curves. 

Since it is on the outside not inside a clear shell, just tape and respray. Your only problem is using spray cans, you will need a load of tape and could end up with a lip of thicket paint where you touched up. I do not get this problem with airbrushing. 

[BuggyDad 4464]

Progress is quite slow but progress, nonetheless, it is. 

I decided not to mask and respray because really I need orange over black as well as black over orange on the light/grille detail, plus I'll be cutting for headlights. Any window masking issues are now covered over with (mediocre) chrome work... 

[BuggyDad 4464]

Well, I guess something had to give... 

Son snapped gearbox. Gives me an idea for another mod though. 

[BuggyDad 4464]

Easy to replace the parts, but I have the beginnings of an idea to strengthen and reduce the likelihood of this happening again, since it's obvious from the design this is a fairly likely occurrence. Ideally want to link the lower arm suspension shafts across the gearbox, fore and aft of the arms. 

At the front this could be done with a piece of carbon fibre board through the gap between gearbox and main chassis. Or a piece of thin, like 0.5mm, steel right on the front of the gearbox, crossing the shafts between gearbox and arms. 

At the rear I think it might be doable with another piece of carbon fibre board but I would have to make a cut across the bottom of the gearbox to fit it. The diff will allow it without fouling but I'll have weakened the gearbox casing and harmed it's ability to keep dirt out. Maybe if I cut really accurately I can solve the dirt issue with some gasket jointing stuff I have. 

I'd need longer pivot shafts but I think shock shafts would be ideal. Unfortunately stock steering links are 2.6mm in the non-threaded section - I think they'd wear a 3mm hole badly.

Or maybe the rear could use a single u shaped piece as pivots, like the front suspension does. It would need to be longer though. 

[BuggyDad 4464]

Meantime I've bodged it with M3 rod, as always! 

It's a bit flexy. The gearbox casing is badly cracked, the link is spaced 30mm back and the ends are free ball joints. But it'll drive I think. I could shorten the link, which right now has no preload on it. 

[BuggyDad 4464]

Made carbon fibre rear suspension mounts to increase strength there and stop relying on the plastic gearbox housing where I broke it. 

 

 

 

There is a downside in that I had to cut into the gearbox housing to take a brace across the rear. However, that piece is braced with bolts fore and aft into the chassis so I am hoping it will be OK. If it isn't I could cut a piece of carbon fibre to take the place of both the chassis/gearbox bridges joining them together at the sides. 

The M3 rod used as pivots won't stay. I think the threads will wear the inside of the lower arms very quickly, so I've kept old arms on there til I sort that. I've found some 55mm shock shafts with e-clip one end and nut the other that I hope will be ideal for this job. 

 

[BuggyDad 4464]

Also followed @Wooders28's suggestion of using gasket jointing compound (Hylomar Blue). On inspecting my gearbox internals they were all spotless anyway but with a better seal now they should have a better chance of staying that way. Piece of cake to apply a thin run of it around the joining surfaces. 

Bottom of the gearbox looks so mucky because I put a bit more on that bit where the two halves are just butted up together, no overlap, and the carbon goes in a hand sawn recess. 

[BuggyDad 4464]

I did the vinyl roof and spoiler and am quite happy with the result. Really like the Tamiya Rubber Black colour and it sprays on really uniformly. 

Then a few coats of Humbrol matt varnish for protection. The Tamiya paint was just as matt as this before the clear coat, so it hasn't changed the look. Rest of the body has Humbrol gloss clear on it, which I don't think is all that glossy. Should I have rubbed it down between clear coats for a smoother finish? 

Thanks @alvinlwh for all the advice. A new scalpel blade and yellow tape for the win!

I deliberately left a bit of orange between the windows and vinyl, thinking it would delineate the two a bit better. Jury's out on that. Will do a few bits of chrome around it I think. Decals to come but there will be very few. 

[BuggyDad 4464]

I put a 5.5t motor in this, just "because it's there" and because the question was asked elsewhere. I left it with a 19t pinion and truck tyres because, well, in for a penny and all that. But also I kind of figured for a first run lower gearing would be more wheelie-prone and that might be the most obvious setup issue.

It's better than I expected except the unglued tyres which, obviously, are a no no. I've now got 60g of extra weight in the nose and that probably helps a lot but it can be controlled fairly well. Can obviously only go to full throttle momentarily in the garden (even though we've a big lawn) and it won't have got close to its top speed, but I think in some locations it would be fun to have that burst of power available. It could get quite a speed up on a a wide open beach at low tide... 

Maybe a better motor would be my old Tekin Redline 7.5t motor, which I think is closer to this than the 10.5, maybe because the extra the 5.5t offers isn't really used much. Think I might look for something else comparable to that.

Will also try it on tarmac with the half bald buggy tyres sometime. That could be a quick route to owning some slicks. 

[alvinlwh 5894]

4 hours ago, BuggyDad said:

I put a 5.5t motor in this, just "because it's there" and because the question was asked elsewhere. I left it with a 19t pinion and truck tyres because, well, in for a penny and all that. But also I kind of figured for a first run lower gearing would be more wheelie-prone and that might be the most obvious setup issue.

It's better than I expected except the unglued tyres which, obviously, are a no no. I've now got 60g of extra weight in the nose and that probably helps a lot but it can be controlled fairly well. Can obviously only go to full throttle momentarily in the garden (even though we've a big lawn) and it won't have got close to its top speed, but I think in some locations it would be fun to have that burst of power available. It could get quite a speed up on a a wide open beach at low tide... 

An idea for my DT-02, also with a 19T. Problem is a sensored BL for a beach runner...? Hmmm... 

[BuggyDad 4464]

1 hour ago, alvinlwh said:

An idea for my DT-02, also with a 19T. Problem is a sensored BL for a beach runner...? Hmmm... 

One of the things I've done is take the circuit boards out of esc and motor and apply conformal coating to them. Since then I have not worried about effect of moisture on either. I can't prove it's had a big effect and I wouldn't claim they're fully waterproof but I do know that I have previously had moisture short across something in the esc and had a motor show sensor issues that required a clean, so that was probably moisture there too. And since coating the car has been driven in all sorts, including being submerged, with no ill effects. And since my RX claims to be waterproof yet there's nothing keeping it off the circuit board I suspect all that is is a pcb coating as well. Reminds me, I ought to do my other motors.