Build Thread D3MON's D-28 Drift

[D3MON]

the Hot Racing SCX30 shocks arrived end of last week while i was in Vegas for work. Unfortunately the springs are too soft, even with the firmest springs in the set. it really sucks as they look really nice and feel very smooth and quality built. Though i don't have an scx30, if i did i would definitely get these.

after a bit of testing with the stiffer shocks for the WLtoys, it still works pretty close to the same, so until something better is found, or i can come up with even a spring set with a better spring rates, I'm going to just plan on those being used, but leaving extra holes so if i do find a spring that will accommodate what i need, will be able to swap them out without needing to print more parts.

it is kind of interesting, both styles of the WLtoys shocks have almost exactly the same spring weight, even though the size, spring thickness, coil count per inch, and diameter is completely different.

it was not all a complete loss though as the springs that so far have been the best weight for the front from HR does fit the shock and they are the same length as the shorter WLtoys ones, so i am going to be using them there.

as you can see the extra holes for use with the longer (gold) shocks for the WL toys, and the lower hole for the shorter (red) shocks for the WL toys and the HR racing scx30 21.5mm shocks.

i do suppose i could do a cantilever/mono shock for the front. this would open up shock length options, but i really do not like the look and fit and would pose height issues especially for lower profile bodies.
Another option that i am going to test first is buying just bulk spring and cutting to fit length.
anyways getting really close i think!

 

[D3MON]

been awhile since I've had free time to make progress but better late than never i guess.

since the beginning i have been wanting to re-do the front end where the lower a-arms attach and i believe have found a solution.

first the Pros that come with this re-design:
-Chassis can be extended to have a front bumper
-Front chassis can now be completely flat, making it easier for 3d printing, and possible to be done in CF
-Bulkhead is no longer part of the chassis so if it fails, wont require a major re-print.
Cons
-Potential weak point, lots of testing and purposeful crashes to make sure its not too weak.
-shortened upper and lower a-arm length, will have to see bump steer ramifications.
-I'm sure there are more I'm not even thinking of....


i also received the Losi Micro B/T turnbuckle (yeah right!... both RH thread...)
going to be re-configuring hub carrier heights etc as they are slightly different and the rod ends are M1.5 thread, which i am not as excited about that as everything was designed with M2, and adding other than is kind of an annoyance for both wrench size, hardware strength and cost of adding another entire mini screw set to get the required fasteners.
The 3d printed ones are doing fine, but you can't get scx24 ballstuds separately, have to order a set of shocks $20 each which only includes 8, and this requires 12.


printing tonight and hope to have an update tomorrow. with it all installed.

next issue that i need to revisit is the rear upper links. didnt notice it before but the inner balls are too tall by about 1.5mm. this causes some camber loss through the shock stroke.
first thought was to lower the inner studs, but the width of the diff locates the bearings directly under the mounts. i can just raise the outers, but it is going to start looking really odd for how tall they are, but might have to just accept it.

anyways, all i have for now thans for following/reading along!

 

[Doom!]

Glad to see you back at it, such a cool project.

 

[D3MON]

Status Update:
Ended up having to revise quite a bit more than i anticipated, had to re-design the upper a-arms, given that the turnbuckles were not RH and LH thread, i decided to revert back to screws as the top link. the 1.5mm hardware is quite a pain to cut the head off and grind/file the cut back to clean enough threads to not tear up the plastic its cutting threads into, and IMO just not something i want to put others through as well if i can help it. the turnbuckles and the rear will still require it though.
I also had to extend the back of the arm, as there was barely any material there, which required alterations to the servo sliders. while doing all that decided to also make it a bit thicker overall.

i am running into some 3d printer tuning issues i believe, as my layer adhesion seems pretty weak, very noticeable on the thinner parts that get threaded as it starts separating at layer lines. the PLA+ i was using seems alot more resilient against cracking in similar/same components.

i also am having issues with consistency of supports and the supported items, primarily the hub carriers, the race in the interior is very "globby" in spots and almost non-existent in others. I'm assuming the material is not sticking where its supposed to and globbing up in the other areas.

because i was not having issues with PLA+ in these areas for now i am probably just going to re-print in PLA. also would be nice to have some color back on it. almost everything has been re-designed/printed in PETG!

anyways onto the pic!

assembling the new front components and comparison:

underside picture: in this one you can see the rear most hinge point which is where it threads, i was having issues with splitting so i made it thicker
you can also see how i was able to make a little tab so i can figure out a bumper mount later.

Assembled:

IMO looks much cleaner with the rod ends, and will be much easier to replicate. Though i do kind of like the rough look with the printed.

don't have time tonight for a test run, hoping tomorrow depending on work.

once everything checks out, going to moving to the rear links/hub carriers. these will need cut off screws unfortunately, but trying to minimize this as much as possible.
anyways hope to have updates soon!

 

[Doom!]

I'm kinda diggin' the textured look for the undercarriage.

 

[CreepyQuarryCrawler]

This was an amazing read, super cool to see where you started to where you are.

 

[D3MON]

I'm kinda diggin' the textured look for the undercarriage.

thanks, lol i just have my 1st layer start pretty low to try to get the best bed adhesion, so its just the texture of my build plate.

 

[D3MON]

This was an amazing read, super cool to see where you started to where you are.

thanks! definitely learned alot through this build, and had alot of fun with it.

 

[D3MON]

was able to do a short run and all seems well with the new parts, did have one "failure" though, and wasn't what i had expected it being (the front chassis re-design) One of the ball studs for the tie rod pulled the threads out of a hub carrier. this was kind of expected though. with countless times of removing and replacing the ball studs, and the burs from earlier on when shortening the ballstud threads, was only a matter of time, and the impacts i was putting it through to test the chassis strength.

Next up is the rear hub carriers getting taller and re-printed. i don't really know how active the rear suspension is, so i don't even know if it will matter but i don't like the camber loss in the rear as the suspension compresses.

 

[D3MON]

Got the rear hub carriers revised and the rod ends replaced

now the links are parallel with the arms, no more issues with camber!

printed out a test bumper as well:

added body post mounting locations so if the "unicorn" mount doesn't work for a body it can be mounted with these.
on the body i am using the bumper mounts would not work because of wiring.

I was thinking of trying to do a TPU bumper, but i think I'm scratching that idea. most bodies for the smaller scales are hard bodies anyways, or 3d printed and wont flex enough for a bumper to do anything.

 

[Doom!]

Got the rear hub carriers revised and the rod ends replaced
View attachment 273585
now the links are parallel with the arms, no more issues with camber!
View attachment 273581

View attachment 273582
printed out a test bumper as well:
View attachment 273583
View attachment 273584
View attachment 273586
added body post mounting locations so if the "unicorn" mount doesn't work for a body it can be mounted with these.
on the body i am using the bumper mounts would not work because of wiring.

I was thinking of trying to do a TPU bumper, but i think I'm scratching that idea. most bodies for the smaller scales are hard bodies anyways, or 3d printed and wont flex enough for a bumper to do anything.

I missed those bright colors!

 

[D3MON]

I missed those bright colors!

lol i did too. tried keeping each color associated with its own version for the most part, only thing that didnt keep with that is the new rear hub carriers and the bumper.

 

[D3MON]

Finishing touches:
Trying another route with the battery hold down. I like the original with the adjustable post and the swing arm to hold the battery for the wide variety of battery sizes it would accommodate, but it also more "pinched" the battery and is not very secure. The battery would "float" a bit where the swing arm being tensioned from a rubber band would lift it.
for me at least it is kind of a difficult area to wrap my head around for a secure placement for a few reasons.
-Firstly if at all possible i do not want anything to protrude up from the chassis on both sides. with the chassis layout, sliding it in while there is something sticking up catches the battery, and also restricts battery length.
-If i do have to do something that does stick up i want it to be attachable via screws, as i want the chassis pieces to be flat so if i ever get there carbon fiber sheets can be used.
-Down is a NO-GO
-Wider will also severely limit body choice.

If i can come up with an alternative it frees up alterations for the RX/gyro tray, cleaning up the weird post out the side, and be able to reinforce certain areas.

First option i am going with is:
Adding a slots and a recessed spot where a rubber band can be slotted into the chassis to hold the battery down against the chassis.
this is most preferred at the moment because it will hold the battery down, and will hold it centered in the battery compartment.

downsides:
-chassis will be weaker where the rubber bands will slot in as it will be recessed so they do not sit below bottom of chassis.
-can limit battery size.

Option 2: bring the chassis forward more and adding in a post setup with a paddle on the install/remove side, and adding in a battery "claw" type deal that holds it centered. this is not as preferred because battery size compatibility will require new 3d printed parts.

Downsides:
-different battery sizes will need new "claws"
-the side that the battery will be inserted will need something to tension it closed.
-potentially can limit bodies.

Option 3: is similar to option1 but more of a failsafe if the tabs to hold the rubber bands are too weak. pretty much simulating the chassis notches but above the chassis sitting over where the tab would be.
like this:

downsides:
-will add height
-can limit battery sizes more so than option 1

option 4: leave it as it is if all else fails.

going to be test printing the chassis for option 1 then will start with some testing and report with the findings.
also gives me an oportunity to print stuff in the red orange again to break up the all black look.

Thanks for reading!

 

[Doom!]

Option one, orange please.
Seriously, looking like a good option, hope all goes well.

 

[D3MON]

not able to sleep yet, so progress was made!
Print came out good, also seems the tabs are going to be easily strong enough.

here you can see the notches a little more clearly:

new RX Tray, without the weird looking bar thing and the hinge mounts:
(here you can see the length adjustment holes. wheelbase adjustable in 2mm increments from 96mm to 108mm.)

all back together:

hoping to have some test runs tomorrow evening!

 

[CertifiedMike]

not able to sleep yet, so progress was made!
Print came out good, also seems the tabs are going to be easily strong enough.
View attachment 273680
here you can see the notches a little more clearly:
View attachment 273681
new RX Tray, without the weird looking bar thing and the hinge mounts:
(here you can see the length adjustment holes. wheelbase adjustable in 2mm increments from 96mm to 108mm.)
View attachment 273682
all back together:
View attachment 273684
View attachment 273685
hoping to have some test runs tomorrow evening!

It still blows my mind that ppl are building their own RCs at home from self-printed parts!
Awesome build so far!
Good luck testing!

 

[Doom!]

I like the adjustable wheel base. Everything looks like it's coming together pretty well.

You might consider rounding the edges anywhere the rubberband contacts the slots, to keep it from abraiding the rubberband.

 

[HPIguy]

It's funny you mention battery mount options. I just got the new battery holder solution for my Driftart. The included option was, em, less than stellar. And that's being generous. Great work as always!!

 

[D3MON]

I like the adjustable wheel base. Everything looks like it's coming together pretty well.

You might consider rounding the edges anywhere the rubberband contacts the slots, to keep it from abraiding the rubberband.

yeah good call! think in the file going to fillet so it looks like this:

just going to file it rounded on the one i already printed.

It's funny you mention battery mount options. I just got the new battery holder solution for my Driftart. The included option was, em, less than stellar. And that's being generous. Great work as always!!

oh that is funny timing. you going to post some pics in your build thread? would be really curious to see it!


Speaking of filing things, having my first casualty of the project. One of the files in the cheap dollar store file set i got 6 years ago is starting to die. Really sucks as its my favorite file lol.

 

[Doom!]

yeah good call! think in the file going to fillet so it looks like this:
View attachment 273770
just going to file it rounded on the one i already printed.


oh that is funny timing. you going to post some pics in your build thread? would be really curious to see it!


Speaking of filing things, having my first casualty of the project. One of the files in the cheap dollar store file set i got 6 years ago is starting to die. Really sucks as its my favorite file lol.

They just don't make dollar store files like they used to, you know, like seven years ago.