Road Rally RR-10: Project Snowball Effect

[morrisey0]

From cheap set of wheels to full build...................

So, I wasn't going to do any more long build projects here, because well, they are long and drawn out, and nobody really cares; they want to see the final product. But, TBH, the forum has been super slow the last couple / few weeks, so whatever, I am throwing a project build out there too early. Sue me. I like to post.

So this project started from a random ebay search result that I ended up looking at a complete set of PRO*STAR RC10 / Tamiya wheels that caught my attention. I figured for $25 for a set of 4 wheels that I may be able to do a RC10/car project was worth just going for it. Once I got the wheels in, I did some digging, and realized I already had a set of old school Sand Blaster tires that fit perfectly (well, not fronts tightly, but I will work that out later).

Unsure what type of "car" to go with, I decided rally car. Road rally, race rally, whatever, it is now a RR-10.

So I then needed a platform and I first wanted to go with a gold pan, but I really wanted to mid motor this thing, and after looking at gold pan mid swaps, I decided to go back to a project that I had started before and abandoned. I had started a "Golden Pan Arrow" project with a mid motor swap on a graphic chassis, but lost interest along the way (not uncommon for me). So I decided this platform should now go to my rally car.

To start, slapping these wheels on a stock B1 creates specs around 265mm wheelbase and 240mm wheel track. So, yea, go try to find bodies in that ballpark! The best I could come up with that may work was a Frewer "racing" Peugeot 405 with a 270-280mm WB and 240mm WT. Yea, racing bodies and rally bodies aren't all that similar, but it was literally the only thing I could find near the specs I needed. They did make a rally version of the 405, so the plan is to just convert the racing body enough to make it acceptable. Remember all those Porsche 911 variant rally cars throughout the years? So yea, something like that.

When getting into it, this is going to me a print heavy build, which I am good with at this point. I have been building in the "purist / authentic" realm for a bit too long at this point, and now it is time to spread some imagination. The rear track of the body was around 250mm, and the chassis was set up stock at 240mm, so some track wideners were printed. I wanted to the rear shocks to be in front of the rear tires, so ultimately, I realized the stock bulkhead became just about worthless, so I built my own. The front may still be an issue as the body is only 235mm and the chassis track is 240mm, but I really don't want to make custom front arms! But we will see as we go. I have this thing about not drilling any extra holes in RC10 chassis, especially not graphic ones. For this build, the mid-motor swap is done on an adapter plate, which causes the trans to be lifted about 6mm. The widened arm mounts are lifted about the same, and extended about 5mm on each side. I then created a space for the shorty 2S lipo pack, which fits nicely on the chassis. It is all looking good at this point.

[XLR8]

Really nice work so far.
FWIW, seeing the finished project is always nice but I like to watch it come together - I always learn a lot from that.
Thanks for taking time to post details.

[morrisey0]

Side tip #1: if you find yourself widening the rear of your B1 a little bit, these super cheap dogbones may work for you. https://www.amazon.com/dp/B07JW31TJ4?psc=1&ref=ppx_yo2ov_dt_b_product_details They end up being 70.2mm total length as opposed to stock 62.3mm. I widened the rear ~5mm each side, and these seem to fit fine. The "balls" are 5.94mm as opposed to stock 6.2mm, but I am hoping that is not an issue in the long run.

Tomorrow's side tip will probably be about how you should not disassemble a modern HW ESC thinking you can just solder in new batt / motor leads. I am only 80% convinced so far that that is a bad idea, but will be 100% in the next 24 hours I believe.

[juicedcoupe]

Tomorrow's side tip will probably be about how you should not disassemble a modern HW ESC thinking you can just solder in new batt / motor leads. I am only 80% convinced so far that that is a bad idea, but will be 100% in the next 24 hours I believe.

Been there. I bought a used 1060 (stupid cheap) that someone had severely shortened the battery leads. After seeing that the circuit board was potted, I just decided to splice the leads.

I came back and added a capacitor pack, splicing in at the same spot. Now, everything looks like it's supposed to be that way.

[morrisey0]

So far, so good on the re-wiring of the ESC. I haven't test it yet, but I did power it up, and the smoke stayed in and it lit up as it should. I would not recommend that project to anyone unless you are completely comfortable with screwing it up and tossing it. HW does a good job of making those boards tamper-proof.

Continued mocking up and printing parts this weekend, and then making changes and printing again, and again. The main parts were the body post mounts using standard Arma posts. I ended up using the exact same upper tower in the front and rear, so saved a bit of time on design there.

The servo mount is on about its 3rd version, and is in the printer now. New JC bellcrank is on order.

Next design is going to be a bull bar mount for the front end, and possibly a wing. For aesthetics, I wouldn't mind finding a produced wing, but I really haven't found anything that comes close to what the Rally 405 had, and especially not in the width needed. Speaking of width, I did some comparing of this body and a 1:1 405, and the wheelbase is almost dead on 1:10, while the track is a little larger than 1:8.

This is how she sits now. That is probably close to final height. The tires tuck fully at this height, and since the chassis wheelbase changes with suspension travel, and the body's does not this is going to be about the best body location.

[MarkyDents]

Really cool and interesting project, the end result was worth the effort. I very much like how you’ve worked around not making additional holes in the chassis
Oh and I too look forward to seeing updated build threads as time goes on

[morrisey0]

I very much like how you’ve worked around not making additional holes in the chassis

I am so far good on not drilling any holes in this chassis, and I am also hoping to not countersink any holes that aren't countersunk from the factory.

I am also going to try for making all the printed parts match, as close as possible, the aged white of the original nylon parts. I am very impressed with the black "tough pla" that I have been using lately, and just got a spool of white in this evening. I am printing some test pieces and going to be doing some dyeing tests in the next few days to see if I can make a match.

[Dadio]

Love the project I can't believe you found a real Peugeot 405 to measure , I thought they were extinct they used to be handed out by immigration in the UK along with a Taxi licence and a council house sorry that may have come across a little non PC .

[morrisey0]

Most of the printed parts are now white ................................. too white! Now time to experiment with dyeing. Problem is that my new favorite filament is a modified PLA, and it is great in most regards, but it does not do well with heat. So, just about the temp you would use to dye your nylon and most plastic parts, is just about the temp that deforms PLA.

[GoMachV]

If you have some leftover parts to test with, try tea. It worked great for the old shapeways parts (which were completely different I know) and you never know, maybe it would work here too. Don’t need it hot, try lukewarm. Might take a while as you are mostly staining it

[morrisey0]

If you have some leftover parts to test with, try tea. It worked great for the old shapeways parts (which were completely different I know) and you never know, maybe it would work here too. Don’t need it hot, try lukewarm. Might take a while as you are mostly staining it

Thanks! I had read coffee in the past and tried it with no luck. I also don't have a good color dye around the house. I will give the tea a try.

[XLR8]

You also might try lightly sanding the surface with some fine sandpaper to give the dye a way to penetrate the plastic.

[morrisey0]

I am not having any luck with dyeing this PLA. I am trying every trick I can come up with, but nothing is working so far. I have faith something will work out though. The lightbulb will click at some point.

The task for today was big a$$ rear wing design / print, and I have to say that I am happy with the results! It is weird that the supposedly simple designs take 4-6 attempts to get right, but when you shoot from the hip on something off the wall, it works out the 1st or 2nd time. You can't tell from the pics, but the wing is an actual true asymmetrical airfoil, flat on the top. The 1:1 car had black side supports, and the main wing painted body color, so that is the intent here with hopefully painting on white being easier than painting on black.

I also had a little time to design the roof scoops. They are in the printer now.

[morrisey0]

You also might try lightly sanding the surface with some fine sandpaper to give the dye a way to penetrate the plastic.

Thanks Doug! This tip is completely accurate in this case! Of course, with my laziness I replaced sanding with tumbling, but same concept and it was required.

I have not done the actual car prints, but test pieces are proving that the miracle dye agent is ................................. Turmeric! Available at your local spice aisle. I read a lot of posts by guitar players / builders (the only people that seem to want to make new white plastic look old) wanting to age their new plastics knobs, switches, and such, and outside of the coffee, tea, and shoe polish suggestions, many people kept mentioning Turmeric. For a couple of bucks from Food Lion, I was definitely going to try it.



This was this evening's results. The battery tray is new ReRe so that has been my goal color. The scoop to the left was not sanded / tumbled at all, and the cube test piece was run through the tumbler for a couple of hours. The tumbeled part is just about dead on. This is room temp, and about 5 minutes of dyeing. My current problem is that the resin pyramids currently in my tumbler have been used many times, and are covered with materials that are staining the white plastic parts. I picked up some new media from HFT today, so just need to replace the media and get the environment super clean so the white parts come out just as clean as they went in. The other issue with dyeing these parts is that they were all printed with less than 100% infill, which means they have air pockets, which means they are buoyant. So far, it seems with constant stirring and agitating, this isn't an actual problem.

[XLR8]

That's excellent!
Actually, tumbling (or perhaps bead blasting?) is probably better than sanding since that might impart a grain pattern and make the parts look like wood.
I've never heard of using Turmeric to stain plastic but I will definitely keep it in mind.