Build Thread D3MON's D-28 Drift

[D3MON]

starting a new project, been seeing some small scale drift car chassis on a few sites and decided to try to design one.
recently i pieced together a wltoys k969 (sort of?) with all aftermarket parts and 3d printed parts, and wanted to try something similar but different, with the electronics.


i typically try to shy away from gears and driveshafts with 3d printing, and possibly still going to be the crux of this build, so i am starting there.
starting with determining the gear sizing, and spacing, and the body that is going to house it.

next turning that into physical parts, checking clearances, etc.

then figuring out the motor mount and spur gear.

First version printed:

initially i was going to attempt to use pinion gears, but i am using 3mm hardware and i don't want the 1/8" to 3mm difference to cause any binding.
i discovered that having straight edge gears can be problematic, so reprinted to have them all be beveled, and printed the motor mount.

with slight cleanup it seems to roll pretty freely which is one of the things i was worried about with printed gears.
next onto the chassis and clearance for required items.

i plan on having the battery (one from my scx24) sitting vertically in front of the gearbox.

working on rear arms,

printed and fitted:

Thats all the progress so far for the day.
to finish up the rear, is working on the rear shock tower, upper link mounting points (hopefully on the shock tower, but might have to be on the trans housing) ESC mount on the back of the shock tower, then working forward on the chassis.

 

[Doom!]

Great job, hope everything works out, love to see this one running.

 

[TeknoJ]

That's neat.

 

[D3MON]

well i thought i was done for the day.
started with making some rod ends for the rear upper links.

installed

decided on just mounting them to the trans case, was going to be a nightmare to route with the shocks from the tower.
ended up working the center/main chassis. kind of at a crossroads with the rear that i dont have clarity of thought for how to approach.
battery compartment and rx mount:
decided on laying the battery flat. there wasn't going to be enough room for the Rx to sit between the battery and the servo.

servo mounts:
i see alot of input regarding different servo lengths, so trying to keep it open to run a longer servo horn if needed.

now to the front end. this is my first time designing a front end like this at this scale, so going to be a lot of test fit and rejections. might take awhile for updates on the front end until i get it figured out

 

[D3MON]

Spent a bit more time on it, appears to be shaping up, or at least looking like an actual chassis.

few things i am not liking on it as far as designed for 3d printing.
The nose sticks down beneath bottom level of the chassis, but at this time do not have clearance to move the hing pins up. waiting on test fit to see how much room i can move up and clear the servo horn.

the second is more minor, but i the servo slide rail/RX try standoff has a little bit of in-step on one side and out-step on the other. originally i was going to have these be 2 separate pieces, but i ran out of room. for final version i believe i am just going to move the RX try post out to match the outside and possibly widen the chassis.

anyways this is the progress so far for design. printing now and should be done in about 2 hrs.

for now not going to have a front bumper on the chassis. the bumper on the car body is 3d printed TPU, will eventually revisit this.
might have some ideas as far as the rear shock tower and ESC plate. will update as i go.

Thanks for reading along!

 

[Beer_Goggles_RC]

Making quick work of this!

Imma have to buy one when you're done

 

[D3MON]

Making quick work of this!

Imma have to buy one when you're done

Thanks!
could be a possibility eventually i suppose depending on how it turns out, mostly just bored and wanted another project.

 

[D3MON]

parts finished printing, little bit of cleanup/processing, and i have a slider!

in the above picture you can tell pretty easily why I'm not excited about the inset of the Rx post.

(can really tell from this angle the shock tower issue explained below)

realized there was a slight miscalculation and going to have to move the front shock tower back about 3mm, which unfortunately is the width of that front bulkhead. though i might just either integrate them. preferred for saving on hardware and simplicity, but having it separate is nice for adjustments and when parts break.

next is mounting a servo (need to take it out of the WLtoys clone first though) onto the chassis and figuring out steering links/servo arm geometry to get the typical steering angles (or close to) of drift cars.
overall feels pretty solid, i know in 1/10 people tend to like flex, the rear has a bit between the RX tray and the gearbox, dont really know if its too much, or if it will matter. hoping to have front and rear shock towers tomorrow.

 

[HPIguy]

That is seriously impressive work!

 

[Lukedavis]

That was super quick! I love the look!

 

[D3MON]

That was super quick! I love the look!

Thanks
i am pretty happy with how its coming together, though i know I'm going to be hitting some snags here soon.

That is seriously impressive work!

thanks!

 

[D3MON]

after 3+ hours last night of research, calculations, and trial and error, i believe i have the servo arm extension and tie rod link geometry and lengths figured out. should be able to get full 90 deg turn on the inner tire, and approx 75-85 deg on the outer. immediate concerns are tie rod shape, going to have to have some bend, and going to need to play with how much bend to get out of the way of the hub that wont impact the tire. really hoping to have these on threaded rods to be adjustable. hopefully more updates tonight.

 

[WickedFog]

after 3+ hours last night of research, calculations, and trial and error, i believe i have the servo arm extension and tie rod link geometry and lengths figured out. should be able to get full 90 deg turn on the inner tire, and approx 75-85 deg on the outer. immediate concerns are tie rod shape, going to have to have some bend, and going to need to play with how much bend to get out of the way of the hub that wont impact the tire. really hoping to have these on threaded rods to be adjustable. hopefully more updates tonight.

Can you not just print an offset into the rod end on the tie rod?

 

[D3MON]

Can you not just print an offset into the rod end on the tie rod?

are you meaning to notch it? or are you meaning having an angled tie rod end?
notching it is not going to work as the rod end is sub 3mm, and the screw/thread rod i am using is 1.5mm.
if you are meaning angled, that is the plan. going to have to test with angles to make sure it clears. I'm assuming somewhere between 25 and 45.
i really need to learn how to make moving joints in Fusion so i can just model the clearances.

 

[HPIguy]

after 3+ hours last night of research, calculations, and trial and error, i believe i have the servo arm extension and tie rod link geometry and lengths figured out. should be able to get full 90 deg turn on the inner tire, and approx 75-85 deg on the outer. immediate concerns are tie rod shape, going to have to have some bend, and going to need to play with how much bend to get out of the way of the hub that wont impact the tire. really hoping to have these on threaded rods to be adjustable. hopefully more updates tonight.

My Drift ART 1/24 uses offset ball ends on the servo arm side to avoid that issue. About 45deg or so.

 

[WickedFog]

are you meaning to notch it? or are you meaning having an angled tie rod end?
notching it is not going to work as the rod end is sub 3mm, and the screw/thread rod i am using is 1.5mm.
if you are meaning angled, that is the plan. going to have to test with angles to make sure it clears. I'm assuming somewhere between 25 and 45.
i really need to learn how to make moving joints in Fusion so i can just model the clearances.

 

[HPIguy]

Pic of the Drift ART setup.

 

[D3MON]

Pic of the Drift ART setup.

thank you thank you!! all the pictures i seem to be able to find online have the steering link behind the upper a-arm/link.

View attachment 259294

ahh. didnt think of that! that may work, only issue i see is being 3d printed ends, i need the little slot to allow the link to expand around the ball without deforming. Petg might be the answer for that in the end, but not as much an option right now for me.

 

[HPIguy]

thank you thank you!! all the pictures i seem to be able to find online have the steering link behind the upper a-arm/link.

Yep, you are welcome. I had to have pics from a group when assembling the front end of mine. So I tried to get a better shot than the one I found. LOL

 

[WickedFog]

thank you thank you!! all the pictures i seem to be able to find online have the steering link behind the upper a-arm/link.


ahh. didnt think of that! that may work, only issue i see is being 3d printed ends, i need the little slot to allow the link to expand around the ball without deforming. Petg might be the answer for that in the end, but not as much an option right now for me.

You don't need a slot. You just have to adjust the entry opening until it pops in there. Print, test, adjust, repeat. I would model the sperical opening in the rod end .2 bigger diameter of the ball. Then make the opening on the side that presses on the ball .8mm smaller than the diameter of the ball. Adjust the opening until the ball pops in there, then adjust the sperical cutout until it fits the ball good.