Build Thread D3MON's D-28 Drift

[Doom!]

So I was thinking, when you get all of this wrapped up, what are you going to do with your free time? Love this projects evolution. Agree about the black fillament, was much easier to see when it was bright colors.

 

[HPIguy]

Very cool progress, still amazed at y'all's CAD skills. Time to print you an A Team van body that will clear that servo!!

 

[D3MON]

So I was thinking, when you get all of this wrapped up, what are you going to do with your free time? Love this projects evolution. Agree about the black fillament, was much easier to see when it was bright colors.

lol i have 2 or 3 more I'm picking away at in the meantime that still need finished up thanks!
ultimately the colors were very helpful with initial design, but now that it is getting more "refined" it doesn't hinder it as much. eventually i am going to get some colored PETG to print it in.

 

[D3MON]

Very cool progress, still amazed at y'all's CAD skills. Time to print you an A Team van body that will clear that servo!!

appreciate it!
That might be in the cards honestly, kind of wanted to do a "cab over" semi body like the 1/10 tamiya ones, but the only thing i worry about with that is all the extra weight up front, especially 3d printed.

 

[D3MON]

did some testing and it is so much easier to drive with the new gearing! dont have to be as perfect with the throttle between letting off just enough and to where the ESC starts being choppy at less than 10% throttle. so far the front arms are still quite solid, whereas before after a pack they showed signs of play. i am not sure how much this is allocated to the redesign or the use of PETG.
i am still trying to dial in the new servo. i am finding that the Digital is quite a bit more sensitive, with analog i was at about 70 gain, where the digital if i go past 55 it starts to twitch really bad when in a drift.
probably should have tried the new servo first in the old chassis then put it into the new redesign, so i would understand better if the changes to the drifting are from the gearing or the servo.

One thing that if any of you mini-drifters have played with or can chime in to help;
weight distribution, for mini-drift. Is weight up higher more desirable? or does it matter? It appears weigth shift builts are the rage for 1/10 but for the small ones is the suspension precise enough to really dial it? question mostly comes from the fact with the new battery i hvae some gap (~4.5mm) between the RX tray and the battery itself. i can either lower the RX try bringing my center of mass down, or i can even go up and use a locater to not allow the battery to go up/down.

 

[luke66]

I have no mini drifting knowledge to help out, but man it's looking good! Do you have plans to release the files when you're finished? I'd love to build myself one of these

 

[D3MON]

I have no mini drifting knowledge to help out, but man it's looking good! Do you have plans to release the files when you're finished? I'd love to build myself one of these

thanks! short answer is ideally yes.
Long answer is that it hinges on how well i can get it to perform which either requires me to find someone skilled with drift, or "get good" myself. last thing i want is to have someone invest into building one just to get a half cocked design and regret it.

 

[HPIguy]

did some testing and it is so much easier to drive with the new gearing! dont have to be as perfect with the throttle between letting off just enough and to where the ESC starts being choppy at less than 10% throttle. so far the front arms are still quite solid, whereas before after a pack they showed signs of play. i am not sure how much this is allocated to the redesign or the use of PETG.
i am still trying to dial in the new servo. i am finding that the Digital is quite a bit more sensitive, with analog i was at about 70 gain, where the digital if i go past 55 it starts to twitch really bad when in a drift.
probably should have tried the new servo first in the old chassis then put it into the new redesign, so i would understand better if the changes to the drifting are from the gearing or the servo.

One thing that if any of you mini-drifters have played with or can chime in to help;
weight distribution, for mini-drift. Is weight up higher more desirable? or does it matter? It appears weigth shift builts are the rage for 1/10 but for the small ones is the suspension precise enough to really dial it? question mostly comes from the fact with the new battery i hvae some gap (~4.5mm) between the RX tray and the battery itself. i can either lower the RX try bringing my center of mass down, or i can even go up and use a locater to not allow the battery to go up/down.

Servos and gyro gain are all personal preference. I personally run a lot lower gain than I did at first, as it really helps with low-speed drifts and transitions. I've also learned a lot about chassis setup, and totally changed that up from what I thought was a "money" setup.

Weight shift is a touchy subject for many. A lot of people will tell you there is no way these tiny cars have any weight shift. I always counter with the fact that if the car moves on it's own, then there is weight shift happening. I also have a good friend that has done weight-shift builds in 1/24 and 1/28 and has slow-mo video to prove it takes place. For me personally though, it's just all about getting everything crammed under the body on these tiny cars. I need to put my DA4 on my scales and see where it sits, as I'd bet it's fairly close to 50/50 as I had to put damn near everything in the center of the chassis (which most RWD guys will have a small aneurysm over) to get my body to fit the way I wanted it. Seems fine to me, but I haven't been back to the track yet either.

 

[D3MON]

Servos and gyro gain are all personal preference. I personally run a lot lower gain than I did at first, as it really helps with low-speed drifts and transitions. I've also learned a lot about chassis setup, and totally changed that up from what I thought was a "money" setup.

Weight shift is a touchy subject for many. A lot of people will tell you there is no way these tiny cars have any weight shift. I always counter with the fact that if the car moves on it's own, then there is weight shift happening. I also have a good friend that has done weight-shift builds in 1/24 and 1/28 and has slow-mo video to prove it takes place. For me personally though, it's just all about getting everything crammed under the body on these tiny cars. I need to put my DA4 on my scales and see where it sits, as I'd bet it's fairly close to 50/50 as I had to put damn near everything in the center of the chassis (which most RWD guys will have a small aneurysm over) to get my body to fit the way I wanted it. Seems fine to me, but I haven't been back to the track yet either.

really appreciate the response and insight!

I really need to get one of those pvc floor mats or some floor tiles to set out in the garage. i keep adjusting the gain trying to figure out what works for me and i seem to chase it back and forth, would be good to have a known consistent surface so i can know for sure that it is me and not hitting a slicker part of the concrete or something.

Yeah i for sure understand there is weight shift no matter what, just if it played as much a part insofar as a major tuning point or "style" as the 1/10, as i have been seeing A LOT of "weight shift" builds to the point of the body/chassis hinged separate the suspension, which alright cool, not exactly where i want to go or am interested in, but more power to the wanting the "scale look".

without body which i know will change alot, i am looking at about a 31/69 weight bias towards the rear, which i am pretty happy that i was able to incorporate the locations to achieve that.

if you get the chance, definitely let me know after testing and measuring what your bias is and how it acts on your track!

 

[HPIguy]

Well, I wasn't too far off.

 

[D3MON]

Well, I wasn't too far off.

wow you were definitely close! very much appreciated! what kind of scale do you have btw?

 

[HPIguy]

I have a "feel" for things over the past 30 years or so. LOL I have these, and will never be without them again.

Disclaimer: You also need the 2kg calibration weight that goes with them. Links to both below.

Scales

https://www.amazon.com/dp/B09QVP5KY4?ref=ppx_yo2ov_dt_b_fed_asin_title

Calibration weight

https://www.amazon.com/dp/B0CBM5JZQS?ref=ppx_yo2ov_dt_b_fed_asin_title

It "seems" like a lot of money. In your overall RC journey over your lifetime, it's pennies in the jar.

Also, when you're all done. I REALLY want to print this thing to replace my crappy 1/18 setup.

 

[D3MON]

I have a "feel" for things over the past 30 years or so. LOL I have these, and will never be without them again.

Disclaimer: You also need the 2kg calibration weight that goes with them. Links to both below.

Scales

https://www.amazon.com/dp/B09QVP5KY4?ref=ppx_yo2ov_dt_b_fed_asin_title

Calibration weight

https://www.amazon.com/dp/B0CBM5JZQS?ref=ppx_yo2ov_dt_b_fed_asin_title

It "seems" like a lot of money. In your overall RC journey over your lifetime, it's pennies in the jar.

Also, when you're all done. I REALLY want to print this thing to replace my crappy 1/18 setup.

definitely going to have to pick on of those up one of these days.
out of curiosity what 1/18 setup do you have?

 

[D3MON]

interesting note, found out something interesting today, SCX30 shocks are sold in 21.5mm or 25mm (I'm guessing depends on which model?) and either of those can be made to work for this chassis, and either cost around 20-25$ for some aluminum ones.

i am really tempted to go for this because as long as the spring weight is close this would be ideal as the setup i am using now uses stock scx24 shock bodies (approx $25), and the "Yeah Racing internal shocks" (approx $30) for the springs alone.


concern with this is in fact the spring weight. unfortunately it is really hard trying to locate specs on spring weights, both with SCX24, SCX30, and even for 1/24 drift chassis. though ultimately i suppose could probably order a spring kit for drift specific cars once i find spring internal diameters.

 

[D3MON]

deciding to scrap the idea with the original body that was to be used with the WLtoys/knock-off car and found a pretty cool Supra Mk4 body for free download.
issue with the first body is the weight, it was HEAVY! approx. 2mm thick! sure it will take a few hits, but just a bit excessive.
unfortunately not going to be able to use this until i either fix the Emax, or get a new servo, but gives me time to paint etc.
after printed and glued together:

coated in UV resin and sanded, ready for cleanup then paint:

Don't really know what color design i want to go with it, but as i am not the best with painting and going to be using rattle can, most likely going to be pretty simple.
Also am looking for a muscle car body with the engine sticking out as if i do it right might be able to use the Eco servo recessed into the faux engine.
the Eco servo definitely feels more precise undoubtedly as it is a digital servo, not analog.

 

[D3MON]

been able to run the car through a few more packs and so far been making decent progress in actually learning, though with this update probably going to go back down as so far has been without a body. that said, the gearing has made driving it much much easier!

Progress/Design updates:
in attempting to fit the new body i realized even with the lower profile Emax servo, it sat too high and wouldn't let the body sit where it should.
i do plan on getting a proper mini drift servo, which shaves another 2-3mm or so from the height but even then would still sit a little too tall. eventually settled on a re-design to make it work.
to get the clearance needed i had to raise the sliders for the servo approx 4mm, invert the servo horn, and the servo now mounts on the underside of the servo mount blocks

Printed and fitted:

the horn is really close to the front chassis plate and will need to modify it to allow for more movement forward for tuning, but this is pretty close to where i had it.
the rear mounts also needed adjusted as the locations were right at the slope of the rear window of the body, this should allow a more wide range of bodies as well.
doing this i did have to lower the "tray" for the ESC.

it appears most ESCs for these drift cars they are in more a hard case than a heat shrunk circuit board, so i believe i am going to make another ESC tray more as a shelf so the ESC can be mounted to the rear shock tower instead. a bit worried about the Gyro and RX as i know the dimensions of what i have and i believe the Year Racing gyro is among the smaller of what is available, and RXs vary wildly in size and that spektrum usually is among the smaller of them not accounting for 2 in 1 combos.

I have also completed the body and painting of the body. first attempt of painting the green over the black base coat got really bad orange peel effect and i dont really understand why, i had to remove it with some mineral spirits, sand it and stuck better the second time around.
i need to solder in the lights and I am going to be ordering some CF vynyl wrap that i want to put on the hood to kind of break it up a bit.

thanks for checking it out! hope to have more pics when the body is fully complete, hoping soon after to start getting some video of it as well.

 

[WickedFog]

You killed it dude! This is one badass build! And VERY well designed!

 

[D3MON]

You killed it dude! This is one badass build! And VERY well designed!

very much appreciated! been having alot of fun with it, and luckily turning out how i wanted it to for the most part.

 

[D3MON]

got the lights installed and soldered up!

i do think for now going to leave the hood as is (green), but will probably put the vinyl on in the future.

down to only a few things on the list before I'm happy and want to call this complete.
Major issue is the shocks. though designing for new shocks is going to be simple to fix, just relcoating holes on the shock towers, finding a good combination of spring rate and shock length is my major concern. i have what i believe is a really good combination, especially up front. but overall its 3 different sets of shocks. rears are the standard WLToys on road ones, fronts are the WLToys "threaded shaft" ones ( the shafts are threaded, BUT there is NOT any preload adjustment as the collar is part of the body) with Hot Racing SCX24 internal spring shocks medium weight.
both the WLToys ones will work at least for the rear, but the springs are really stiff for the front.

I am currently waiting on the Hot Racing SCX30 shocks to arrive in the mail and should be here end of next week.
really hoping that these are going to be the answer.

another thing that has me worried, is i know this works on MY printer, with the tolerances and everything, but i also know that mine isn't perfectly tuned primarily because i just don't have the patience/understanding. so i do not know 100% if everything (mainly the gears spacing) will work more universally. Being a very visual learner, walls of text just get me anxious and lost lol. Before long i may be looking for people if they are serious to want to do this build so i can adjust as necessary.

 

[Doom!]

This has been fun to follow along with, and a very cool project. Your dedication to working through all of the issues, and variations is commendable to say the least.