VFD Capra...Can I Still Call It A Capra?

[Panther6834]

Originally Posted by Kingmeow

You need to start that 12 Step Program...wait, make that the 1,000 Step Program. You'll probably see a lot of us in it.

How about a simple 2-step program:

1) If you're married, and your spouse is really strict on expenses, avoid this hobby.
2) If you're single, or have a spouse who doesn't care about your extra expenses, go buy more RCs.

Program complete.


~ More peace, love, laughter, & kindness would make the world a MUCH better place

[mjensen]

While RC rehab may be in order, going a little crazy with this stuff really doesn't affect anything except my wallet.
I've been divorced for 20+ years, am retired, and my only close family is a 200 pound Newfoundland that couldn't care less what I do as long as it doesn't interfere with meal time. I feel pretty fortunate that I have so much time I can mess around with this stuff while still having time to do all the day to things everyone has to do.

In the end it's not so much insane but rather that I've been having so much fun with this project that it's hard to stop. Pretty much what a hobby should be.

[meatmonkey]

You've really shoe-horned that vanquish trans in there. Good job.

I dont have a 3d printer, but do have a bucket of al and steel brackets and doohickey's that didn't quite fit the first go around. Funny how down the road what doesn't fit the current project may be near perfect for another.

Its nice that you have two capra's so you can give us a comparison between your trans setup and stock.

[mjensen]

Originally Posted by meatmonkey

You've really shoe-horned that vanquish trans in there. Good job.

I dont have a 3d printer, but do have a bucket of al and steel brackets and doohickey's that didn't quite fit the first go around. Funny how down the road what doesn't fit the current project may be near perfect for another.

Its nice that you have two capra's so you can give us a comparison between your trans setup and stock.

It took a lot of tries to get things to fit but it seems to work.

To be honest I was ready to ditch the whole 3D printed chassis idea last week after trying to simplify the design so I could print the complete chassis as one piece. 50 hours into a 70 hour print it failed and I originally blamed it on my dog for running into my printer bench but I tried the print again and it failed in the same spot so I guess there was something in my redesign that was too complicated for my slicer to resolve properly. I have changed the design a bit less radically to combine a few pieces and simplify things some and I'm currently printing out what I hope will be the final chassis. It's been fun but it's gotten to the point I have to say enough is enough. Well...for now anyway. I did pick up some cheap 100mm shocks to see if I could gain back the articulation I lost with the 90mm shocks compared to the stock Capra. If that works out I'll have to see what I can find for decent shocks closer to the stock Capra length.

[mjensen]

A quick update for anyone that might still be following this.
The latest redesign didn't exactly go to plan which is not really surprising when you don't actually have a plan.

I did make some progress. I installed a set of cheap 100mm shocks to replace the 90mm shocks I've been using (internal spring shocks kind of suck to set up) and I now have about the same articulation as the stock Capra. I also redesigned the front clip to add body posts and do away with the 2 screws that originally held the body down.
My biggest set back may all be in my head but I've been thinking that with the aluminum axles front and rear, rear servo for steering, full size servo for the DIG, etc, the car is getting a bit chubby and might benefit from a 550 motor. Unfortunately the VFD transmission won't fit a 550...without some work. A longer bell housing (which I've already designed in CAD), a longer top shaft from the spur and some minor changes to the skid are about it. The top shaft is the only thing I can't do with the tools I currently have. I used to have a small metal lathe and a welder so I know it wouldn't be a major project to turn a new shaft or weld a piece into the stock shaft and true it up on a lathe. Any thoughts? Is the extra torque and power of a 550 brushless worth looking into for a 7 lbs+/- crawler?

Oh, and I did finally get a Capra interior so I could make sure everything on the chassis clears. Fortunately it does.
I haven't taken any pictures recently but I probably should if for no other reason than to document how far down the rabbit hole I've fallen.

[twade984]

I could be wrong, but I think a lot of the popular brushless motors are 540 sized. Holmes hobbies puller pro, tekin roc412, castle slate...

There are probably plenty of vs410’s running around with those motors and weighing in close to what yours is?

Looks good btw thanks for sharing.

[Lashlee]

I run a 540 HH Puller Pro in all my rigs (4-10, Enduro and Capra). I'm not sure you would need a "bigger" motor considering all of the KV options out there from the various manufacturers. All three of mine weigh in around 7-8.5 lbs ready to run

[mjensen]

Thanks guys. It sounds like the 550 would be overkill plus I realized that because of the way I designed the front motor mounts for the VFD transmission they are part of the chassis and I would need to reprint the whole chassis as well as the front clip to make things fit. The polycabonate/carbon filament I've been using, while very strong, is really finicky to print and I really don't want to spend another couple of days babysitting my printer. I do appreciate the advice.



Anyway, here's a few pictures to follow up last night post.

[mjensen]

Not sure this can be considered a build thread since most build threads actually have an end product in mind and that was never the case here. But, anyway, I've noticed most build threads list all the things that have been used in the build and since I've decided enough is enough, at least until I get out side and start breaking things, here's what I've gone with.


1: Vanquish VFD transmission w/DIG which I chose for no other reason than it looked cool and I liked the design.
2: Vanquish front Capra axle pretty much required since the VFD needs an offset pumpkin.
3: Supershafty front Capra axle on the rear since the VFD rear output needs a center pumpkin axle for clearance if I wanted rear steering which I did.
4: Vanquish Incision drive shafts and Capra steering and bottom links. Top links are custom made because the top link mount points of the VFD skid aren't close to the same as the Capra links.
5: Protek370TBL front steering servo, Savox 2290 rear steering servo.
6: Reefs 299 low profile servo for the DIG.
7: Holmes Hobbies 13t Crawlmaster Pro motor. Currently with 20/46 gearing which gives me 49/1front, 52/1 rear final gear ratios. With the gearsets I have I can go as low as 88/1front, didn't figure the rear for this but it would be lower. The VFD has a lot of room for gear changes.
8: Proline Hyrax tires and 2 stage foams on inexpensive China wheels (that are actually very well made.)
9: Hobbywing 1080 ECU largely because it was cheap, had a good reputation, and I wasn't sure if I wanted to go brushlees.
10: Shocks are a work in progress but currently Desert Lizard 100mm internal spring shocks.

11: There's some other odds and ends like a Castle BEC and some Holmes wiring for the servos but that's pretty much it.
It's all attached to a polycarbonate/carbon fiber 3D printed chassis that I designed in Fusion 360 many times over and printed probably twice that with all the changes I've made. The body is the top half, give or take, of the Capra cage, really all that's left of the Capra hence the title of the thread.
As I said at the beginning of the thread, this wasn't really a serious project. It was just something to keep occupied while the virus lockdown was going on ,which unfortunately in my state it pretty much still is. I didn't go into this planning on building a better Capra, only something different. If it works, great. If not, it doesn't matter because I had fun doing it.
Anyway, I hope to get the electronics installed this weekend and maybe at least get to run it around the yard.

[Statenheimer]

Looks like fun stuff. Keep up the good work.

Did you get out in the yard with her this weekend?

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[mjensen]

Originally Posted by Statenheimer

Looks like fun stuff. Keep up the good work.

Did you get out in the yard with her this weekend?

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I still haven't been able to take it out for a drive. I did get the electronics soldered up and installed over the weekend but had a couple of issues with the receiver. One being that he radio box I have was sized for the receiver that came with my radio which is now in the stock Capra. The new receiver is a different model and the plugs are laid out differently so it won't fit in the box. It didn't really matter in the end because the receiver was DOA, first Futaba failure I've had and I've been using their radios since the 80's. I ordered it online since my local shop was closed because of the lock down but they are open now so I'm going to see if I can get a credit for the dead one and pick up a new one locally. Hopefully it will be running soon.

[mjensen]

After an unsuccessful trip to my local State park, the closest place I know with good rocks that's accessible to the public, I've gotten a bit sidetracked. Both Capras are/were running fine except the stock Capra's dig had issues going from locked to unlocked which seems to be a common problem. I wasn't able to get either of them out on the rocks because my State is still quite locked down and while most of the public lands have been reopened they've put parking restrictions in place to discourage people from using them. I could have parked on the road outside the park like many others did but the hike at my age, carrying 2 RC cars, batteries, etc, wasn't something I wanted to do.
Anyway, kids have gone back to school this week so hopefully things will quiet down so I can try again.
In the meantime I've prototyped another version of the chassis that will allow the use of aluminum or carbon fiber flat rails in the event that the 3d printed one doesn't hold up to the abuse. It also gives me the option of changing link geometry more easily if needed. I still need to figure out the sliders to bolt on to the chassis so it's a work in progress.

[OSRC]

Fantastic work on those chassis, both versions! Love the all black too.

What state are you in (out of curiosity?) Even here in PA, the state parks have been open for a while.

[mjensen]

Originally Posted by OSRC

Fantastic work on those chassis, both versions! Love the all black too.

What state are you in (out of curiosity?) Even here in PA, the state parks have been open for a while.

Thanks
I'm in Maine. Most of our public lands were opened up back near the end of June but the Gov. put parking restrictions in place trying to limit the number of people using them for social distancing reasons. They'll allow100 people in a local 10000sf grocery store but restrict a park with hundreds or thousands of acres of fresh air to 50 or 100 cars. Seems a bit over the top to me but what do I know. Maine's major source of revenue is tourism and the rules that have been put in place to deal with the virus have really hurt a lot of businesses and workers as has happened in many other States.

[Fricker08]

I’m still amazed at your 3D printing ability. That’s pretty impressive right there. Curious how this new chassis works out for you!


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[mjensen]

Originally Posted by Fricker08

I’m still amazed at your 3D printing ability. That’s pretty impressive right there. Curious how this new chassis works out for you!


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Thanks. I'm still learning as I go but it's getting easier as I figure out the limits of Fusion360 and my printer.
I really enjoy this DIY stuff and there are so many impressive builds on this site but some RC videos I found on youtube this morning really made me realize how lucky I am with my 3d printer, computers, easy access thousands of RC parts, and the internet for information and ideas.
The guy's name is Rini Anita (https://www.youtube.com/channel/UCPp...AYzxQ/featured) I'm not sure if we're allow to link youtube sites so please remove if necessary.
The way this guy takes things most people would consider trash and turns them into something he can use is, to me, far more impressive than anything I'm doing.

[mjensen]

I had to walk away from this project for a bit to get my house ready for winter but I've gotten back to it in the last few days. I liked the idea of carbon fiber flat rails for the main structure of the chassis so I did a redesign based on one piece 3mm rails that is only 80mm wide which will fit inside the Capra cage with some trimming of the front clip area to clear the forward mounted motor and cutting of a section of the rear tubes to clear the rear steering servo.
I've not finished trimming the Capra cage yet but the chassis parts are all designed and printed. I purchased some 3mm carbon fiber for the rails but they are currently 3d printed as I haven't found anyone to route the carbon fiber for me yet.

I removed the cosmetic bell housing from the VFD transmission as with it gone I was able to put an electronics tray in that area and the battery tray, which remained where I had it in the other designs, was shortened to fit the 80mm rail width but still fits the 1500mAh 3s battery packs I have. The receiver will go in the fuel cell. One of the pictures I've included gives a rough idea where the electronics and battery are going to go.
If anyone knows anyone with a cnc router and experience cutting carbon fiber please let me know.

[JSterrett]

Super nice work man! I don't have any experience with CF, but I do have access to a router and can do Aluminum.

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[Fricker08]

Hey looking good man! That’s pretty wild and impressive. Hope you find someone to route that carbon fiber. I’ve been waiting over a month for my chassis from Procrawler out of Hungary because the place that was doing their work told them to pound sand. Granted it’s FR4 but I think probably close on properties.
Looking forward to seeing how this version works out for you


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[mjensen]

Originally Posted by JSterrett

Super nice work man! I don't have any experience with CF, but I do have access to a router and can do Aluminum.

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Thanks! I had a set of aluminum rails that I hand cut out of 1/8" 6061 in one of my first designs. There's a picture of them back on the first page sitting on top of my box of rejected parts. They worked fine and were plenty strong but it was a lot of work to cut them so when I changed the design I decided to try the 3d printing route. I decided to go with 3mm carbon fiber for this latest design since while the 3d printed rails were quite stiff I question their durability. Plus I figured the carbon would be easier to hand cut and machine than the aluminum. It wasn't and it was also almost 3 times as expensive as the 6061.

I'm not set on the carbon and I think aluminum would work just fine. Maybe I could send you a copy of the design file, (not sure what file format you'd need, .step, .stl?) and you could tell me any changes to things like radius, hole sizes would be needed and give me an estimate of what it might cost, materials, labor, etc to make the rails out of 3mm or 1/8" 6061.