My DT-03 for fun driving and tinkering

[BuggyDad 4474]

2 hours ago, ThunderDragonCy said:

@BuggyDad Those tower reinforcements are brilliant! I am a big fan of those JC Pepperpots. Very nice. 

Cheers! 😜

I have winced many times recently as a child has sent this thing hard into the ground upside down. I think what it needs next is little sheet metal skids at the shock mounts because the towers are now wearing through abrasion rather than bending 🙄. May even be that adding just a washer would do it. 

Same mod (front anyway, I'm less sure on the need/effectiveness for the rear) on 2 cars and thus far towers and chassiseses remain intact since. That's a good 3 car-months of running, which previously would've averaged us maybe 3 towers and a chassis... 

[BuggyDad 4474]

Can you spot all the broken bits? 

On the plus side, while there are many issues, they're all small and I think I have the necessary spares. And some have been a long time coming. Orange also needs time in dry dock and a significant refit for general wear but I think we'll leave that until the already spectacular level of suspension slop becomes actual breakages. 

However, I've been considering for a while the idea of building up a guest kids basher car out of my NIB kit. Bearings and pinion, all of my strength mods, no mods for performance at all except maybe a cheap waterproof brushless combo and a couple of extra ideas for further protection. And probably use as many old parts as possible along the way so the new stuff is kept as spares. Then yellow can go back to being treated nicely and adjusted for performance. 

[BuggyDad 4474]

The sand paddles are a bit nuts. Good straight line grip and some kind of anti-grip sideways on wet grass. Kind of entertaining! Grippier than spikes on tarmac though. DR down to 60%. Spikes will go straight back on and these saved for the beach only I think. 

[BuggyDad 4474]

Which reminds me. My efforts with gluing tyres haven't been all that successful to date. I thought I'd want the ability to remove them either to change tyres or cleam/dry foams out, so I used shoe goo first, with reasonable results but not much longevity, then E6000 because I thought it might be a little stronger or last a little longer. Unfortunately it's worse on both counts. I think I'll have to go to superglue. But I'm worried about the inability to dry foams out then - we live somewhere pretty wet... 

[Kol__ 3377]

7 hours ago, BuggyDad said:

Can you spot all the broken bits? 

However, I've been considering for a while the idea of building up a guest kids basher car out of my NIB kit. 

Ha, they looks pretty badass with the bigger wheels and tyres mate. Bet they rip along like that!

Glad to hear you're considering a guest basher, should limit the abuse yours get dished at it.

[kwkenuf 184]

@BuggyDad I didn't see it mentioned... what driver figure did you use in the beginning?  My daughter wants one in hers, and the one you used looks like the right size.  Thanks!

[Tigerdriver 23]

Catching up on the whole thread, some good inspiration there

 

Makes my neo fighter adventures look very vanilla

[ThunderDragonCy 7878]

13 hours ago, kwkenuf said:

@BuggyDad I didn't see it mentioned... what driver figure did you use in the beginning?  My daughter wants one in hers, and the one you used looks like the right size.  Thanks!

Looks like the regular 54626 driver figure set. 

[kwkenuf 184]

6 hours ago, ThunderDragonCy said:

Looks like the regular 54626 driver figure set. 

Thanks.  I did some looking to gain knowledge on the whole driver figure world, and just went cross eyed doing it.

[BuggyDad 4474]

On 4/6/2022 at 8:18 AM, ThunderDragonCy said:

Looks like the regular 54626 driver figure set. 

@kwkenuf. Yeah I think this is right. It's a standard one. It's quite tight in there and you have to find somewhere else to put your receiver. I put mine alongside the servo but that's not ideal and I later took the driver out and put the receiver back in its normal spot. 

[BuggyDad 4474]

So a few months down the line, and after a weekend of 'orrible beach running with my son and friends I thought it might be worth me summing up some of the things I've done and their effects, in case useful to others. Some quite simple stuff has been game changing. In no particular order... 

Conformal coating circuit boards

Game changer for scruffy wet bashers like mine esp if you use sensored motors. I went back to an untreated motor and the other day in beach running it went to sensorless mode after one battery pack. Pinched the sensor board out of my old spare (coated) and all is well again. Will clean and coat the other one. It's so easy to do, costs little, and dramatically improves the water resistance of both motors and ESCs. 

Tower braces

Game changing also. Loads of breaks before. None since. Not one (so far). Getting on for as much running after as before. I'm talking about both tower and chassis breaks. Will also be due in part to the change to carbon stays but only in part and they won't help avoid chassis breaks (maybe even negative effect). Front almost certainly much more important than rear. Would like to add some kind of skids as well to manage wear to the carbon. 

Hex front conversion

I really like this. More beneficial than expected. Running two cars in parallel, one with hex conversion and the other with Mad Bull uprights. Both with truck wheels. 

The expected benefit is mostly just to use a wide range of wheels. The unexpected is that the car with Mad Bull uprights bends the axles quite easily. It's definitely a weak point when you go to truck wheels, although I don't think it is with buggy wheels and stock short axle uprights. Tried Tamiya white nylon uprights and some aftermarket aluminium ones, Tamiya much better. But zero failures on the hex converted car. Primary reason is likely to be that the hex wheels have much less offset (Aqroshot /Blitzer wheels have huge offset) and so the bending moment at the axle is much reduced.

There may be a downside in steering. More Ackerman because of the shape of the uprights. In practice I think my car drives just fine but I wonder whether a more experienced driver would spot a negative effect. 

Overall though, I think I'll do this to my son's car rather than waste more money on uprights. In fact I should probably get on and order the bits, since we're out of spares. 

Bracing the rear suspension arm mounting points

Net positive effect but jury's out as to whether it's worth it. The car run as stock has a lot of slop now but it's also higher mileage, and it's only slop, not breakage. I had just one break. The modded one has no slop and I strongly suspect it'll take much longer to develop any with the harder carbon material, plus the outboard position of both braces. And no gearbox casing cracks so far I think is a good signal that I haven't introduced a significant extra weak point. But it's a more faffy mod than the others and you want to be careful to avoid breathing in carbon dust when cutting. And it's only a relatively minor weak point it's fixing. And the slop on a DT-03 for bashing isn't really an issue in driving, especially not ragging them on the beach. 

Gasket compound to seal gearbox

Who knows. I haven't actually had a problem without it, but to pop a bit in there on assembly is easy as pie. 

DF-03 aluminium damper set

Controversial perhaps but I actually think these are a backward step simply because they're an imperfect fit. And it's my most expensive mod. The back ones are great but the fronts at full compression give higher ride height than CVAs. So they effectively reduce travel, and they introduce the issue of shock bottom-out before chassis. I intend to swap them back. Unless I can find really teeny tiny bottom eyelets to take the height down. My B64 suspension is generally way better and so I'd like to find a way with the DT-03 to get more droop, more front travel, lower spring rates F&R but with enough rear preload for a good ride height. 

I'm just talking about the unusual stuff here, not the well documented hop-ups. 

 

[BuggyDad 4474]

Anyone run the DF-03/TT-02B aluminium damper set 54993 (on any chassis - that doesn't matter)?

I've damaged some plastic parts from the V tree and am wondering whether I can replace with 54871 "Reinforced V parts for TRF dampers". They look the same to me and I like the reinforced idea, for obvious reasons. Mine came with pretty soft plastic. I think the direct replacement would be 53334.

I hadn't got these shocks running any better than the CVAs, but I think I will do shortly now I've got my head round the idea that they just need much much lighter weight oils. They feel really smooth where my old CVAs are getting a bit rough. 

[matisse 1581]

5 hours ago, BuggyDad said:

Anyone run the DF-03/TT-02B aluminium damper set 54993 (on any chassis - that doesn't matter)?

I've damaged some plastic parts from the V tree and am wondering whether I can replace with 54871 "Reinforced V parts for TRF dampers". They look the same to me and I like the reinforced idea, for obvious reasons. Mine came with pretty soft plastic. I think the direct replacement would be 53334.

I hadn't got these shocks running any better than the CVAs, but I think I will do shortly now I've got my head round the idea that they just need much much lighter weight oils. They feel really smooth where my old CVAs are getting a bit rough. 

You can, I used them on my DT02X build, best dampers I ever made.

[BuggyDad 4474]

37 minutes ago, matisse said:

You can, I used them on my DT02X build, best dampers I ever made.

You can use them on a DT-03 or you can use the TRF V parts on them after you break them using them on your DT-03? 😜

Yeah, I fitted them and then didn't run it much so didn't get the settings right. I've learned it's not the fault of the shocks at all. The quality is superior. I just need to get the right oil to get it just right. And the right springs (could do with something a little longer and a little softer). Once I get this right (and replace the V parts) I think the DT-03 will drive beautifully. 

Anyone know of any springs that are 5-10mm longer than the stock ones but as soft as (or a little softer than) the red "soft" front ones in the DT-02 setting set?

The front of the DT-03 has taken a lot of fettling for me, and I think I still need to maximise droop on it, hence the desire for a longer but soft spring. Maybe I won't need it once I get lighter oil but I suspect it would still be preferable. I could of course just stretch those red ones I have. 

[BuggyDad 4474]

I put 500k oil in the diff. Saw it recommended somewhere. It's now a very stiff diff. I've only run it on a hard frost so far so I have no idea how I feel about the change yet. But nowhere I run it has all that much traction anyway. 

Regardless of that change the car is hugging the ground better than it used to with a reduction in damping, which I like. The fronts are still a bit hard though so I will get some 100 & 150cst oil next time I place an order somewhere. I'd like more front droop too if I can find a way to achieve it. 

[BuggyDad 4474]

I ran my DT-03 today, which now has Schumacher full spikes on the back as well as a bit more refinement to the shocks (with more to come). Pretty much sheet ice meant grip was awful but this thing is now hugging the bumpy ground better than ever before. Really active. It finally feels like it's running like a buggy should. These spikes are a bit hard to find. I guess they have no racing application nowadays. But for me they're ideal. Think I can switch between these and mini spikes, both being much better than the harder compound Tamiyas.

One of the things I'd like to try as a future little project is a Kamtec Rough Rider shell. I like the RR very much. Was marvelling at one in a shop the other day (also an original Holiday Buggy), I like the retro look and this model in particular shouts 1970s to me, plus I can lose the vulnerable wing and use cheap Kamtec shells. If I can make it fit, for which I'll need to extend its nose for DT-03 wheelbase. Maybe I can get away with some spare lexan offcut for this. 

[Andreas W 1555]

I agree with you that Schumacher full spike and Mini spike are more or less THE tires for low grip conditions. After trying different tires bought on clear out sales on the Tomahawk I have come to that I wear out one set of each of the two Schumacher-tires pr season. That is when I use them more or less only for postal racing. When they are not grippy enough they can be used for bashing. Halfway worn down Mini Spikes are superb for the Grasshornet on astro, if I feel for running it there.

 

With your BL motor you probably wear out at a more frequent rate than I do. 

[Kol__ 3377]

On 1/20/2023 at 5:44 PM, BuggyDad said:

Schumacher full spikes on the back as well as a bit more refinement to the shocks (with more to come).

Nice one, I'm running the full spike Schumacher's on the front of my DT-03, with Tamiya 53059's (Madcap, DT-02 etc.) on the rears. Perhaps next I'll try the Schummies on the rear as well mate.

So what's all this rear shock refinement about then?😉

[BuggyDad 4474]

10 minutes ago, Kol__ said:

Nice one, I'm running the full spike Schumacher's on the front of my DT-03, with Tamiya 53059's (Madcap, DT-02 etc.) on the rears. Perhaps next I'll try the Schummies on the rear as well mate.

So what's all this rear shock refinement about then?😉

Full spikes on the front? I might try that too. I've got soft mini spikes (maybe Ballistic buggy ones) on the front. They seem to be excellent. 

It's the front that needs a bit more shock refinement. It's not bad but I'm not satisfied. The never ending struggle to get it to be smooth and active while still soft enough. My springs are so light that they struggle a bit to overcome the friction in the shock, especially in this cold weather. I might strip and rebuild my DF-03 ally shocks this week. Currently it's got ally front, CVA rear because I broke a part on the rear. 

[Kol__ 3377]

Yeah I've nothing to compare it to as I ran the full spikes right from the initial build, but it turns well and grips well imo👍

With regard to the front end suspension I find that with any of my 2WD buggies, getting a good 'lift up the front end an drop' test to assess the spring rate and damping, is always a bit meh as the springs would have to be so ridiculously soft to display the same result for that test as say the rear for example, that they would be just rubbish on a run.

So I've gone stock CVA's with stock springs, but with proper plastic pistons (3 holes) and rods, and a super soft oil. Seems to work fine on a run and sort of displays a notion of compression and damping movement when the front end is lifted up dropped back down from vertical chassis angle down to the floor.

[BuggyDad 4474]

Right, I sat down and had those front shocks to bits. There was quite a lot of friction in them. I changed the o-rings and they are so much better. Old and new are both Tamiya red but I have a feeling the old ones may never have been quite right. Either that or they've expanded or deteriorated in less than a year. Is that a thing? They were certainly bigger. They squeezed the shaft when the bottom part of the shock body was done up the last turn. The new ones don't. 

It's damper set 54993.

Also moved them to out front. A bit vulnerable perhaps, but it was annoying not being able to access them easily. And in to the innermost tower holes. I may look to a longer bottom bolt with a spacer and washer out front to take the hits, but at the same time I do wonder whether this is a really vulnerable spot - they are 35mm off the ground because of so much kick up, which is quite a lot of clearance. The rears are in a similar spot but it's both lower and on the receiving end of whatever comes up off the front tyres, and while those lower eyelets have worn, they haven't gone up in flames. Protecting the top is probably higher priority 

Worth noting that the red o-rings are cheap as chips on PJ. £1ish a bag. Bung em in your basket. 

[BuggyDad 4474]

I fitted a pair of @ThunderDragonCy's 3d printed 3° toe-in rear uprights.

I've only given it a brief test run but holy moly, rear toe-in seems to make a big difference to keeping it straight under power. Even on my currently a bit neglected buggy in my rough and slippery stone and dirt yard. 

[BuggyDad 4474]

Wing Mount MK6 (maybe)

This buggy is in need of some cosmetic love. It's been without a wing for some time now. Mechanically it is good though. 

So to that end I have gone miles down the Fusion360 rabbit hole. When I looked up from the screen last night I was shocked to find it was gone 1am. And yet still I rebuilt it again from the ground up today when I should be working. Here's where I am so far:

It is intended to create broadly the same wing position as this:

Some say too high, but I like it.

I did a design with two struts either side, structurally roughly as the original, but I want it to bend and spring back rather than buckle, so I'm working on the hypothesis (I have no idea whether this'll work, mind) that a single tube (when viewed from the side) if printed in the most flexible material I can find (TPU) might be a good option. The curved single tube idea is also relatively straightforward to model, being just  a curved line linking defined points that aren't all in a plane. 

Or I might print two or three different ideas. Won't print for a while anyway - have to let a few other ideas bubble away (hopefully including body mounts for the DT-099 Flake ice cream van) before I get to minimum order quantity. 

The obvious weak point is immediately above the top tower screws. That might get beefed up a little. 

Has anyone much experience of the flexibility of TPU? Do you think this'll work? 

[ThunderDragonCy 7878]

@BuggyDad That looks great! I have so been there at 1am! TPU would be great. Its probably more flexy than completely ideal, but won't break. I made some super short bumpers for my FF01 out of it to fit my 306 body. 

[BuggyDad 4474]

42 minutes ago, ThunderDragonCy said:

@BuggyDad That looks great! I have so been there at 1am! TPU would be great. Its probably more flexy than completely ideal, but won't break. I made some super short bumpers for my FF01 out of it to fit my 306 body. 

"a bit too flexy" may be no bad thing as far as material choice is concerned here. Although if it's very rubbery I think I'll need to thicken it up or brace beneath. What I've got there is a 6mm diameter solid, about 50mm long. Reckon that'll wobble about like jelly, or at least hold itself roughly in position in normal running?