RC Hypercar Pt8 - World's Best Handling RC Car?

The RC Hypercar has finally posted the insane numbers that it was built for, over 4 lateral G of monster cornering.
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#RC #3dprinting #car

[@bigbuckoramma]

Need to visit a RC Touring/Pan Car track, and get some real world lap data to see what it is really capable of, and in comparison to a top flight Touring Car and Pan Car.

[@IndeterminateDesign]

Yeah, I'd love to do that. I need to find a better driver than myself. This car is far more fragile than your typical RC car, and I know I'd run it straight into a wall.

[@aemrico]

Awesomely done

[@bytesandbikes]

Awesome. The high speed run footage looks unreal! 😊

[@nestoNESTOnesto]

I'm taking credit for that Sweep tires idea 😀

[@senggyu]

nice!!! I'm always watching your video!! Great work!!

[@IndeterminateDesign]

Thanks! I'm so glad you enjoy these kind of videos.

[@loopie007]

You can never have too many sensors. The next step will be to make daughter boards with 2~3 sensors on each board to set on each corner of the car. Then run CAN bus back to the primary VCU for recording and such. Don't forget to set up ride height measurement sensors on the front and rear of the car so you can see what your aero forces are doing.

[@IndeterminateDesign]

I love the idea of having daughter boards on each of the wheel sensors. Running SPI in a noisy environment like this is far from ideal. Also I have 10 wires with the temp sensors, so CAN would help a lot with that.

[@JoevsRc]

Looks Amazing!

[@nonoffensiveperson9877]

Looks good too!

[@Liberty.Francis]

Amazing work! Anxious to see you get back to the speed car project

[@IndeterminateDesign]

Thanks! I actually built a new streamliner, it just kind of sucked though so I haven't had the motivation to film something about it lol. If I can get a few things fixed on it I'll try to run it again and film it this time.

[@EngineeringAfterHours]

This is awesome! I think it'll even crush my fan car over 30mph. It's comical that anyone would think aero doesn't work on modern RC cars.

[@IndeterminateDesign]

Thanks! Once I saw your videos I knew the aero would work if you could build a suspension around it. Especially with proper airfoils. I can’t believe more RC cars aren’t using this. Once I get the AWD working I’d love to run it against your Vendetta.

[@driftmeister2244]

Any RC racer know that aero works. The bodyshell have a big impact on handling .

[@EngineeringAfterHours]

​@IndeterminateDesign sounds good, let me know when you want to run a test.

[@temyraverdana6421]

You are magic! You are doing an invaluable amazing work. Thanks for share your study and learning

[@IndeterminateDesign]

Thanks so much.

[@wildgophers91]

Ohhhhh I'm excited to see the wheel encoders and what you do with them!

[@IndeterminateDesign]

Yeah. I hope that we can do some cool traction control with them. Accurate to 0.3 degrees at 28,000 rpm. Electronics are crazy.

[@letsdosomething6691]

I once made an aero kit for my traxxas bandit vxl out of cardboard boxes (I got the inspiration from this channel and projectair’s channel), and I can tell you the people saying that aero has no effect at that scale are dead wrong. It has a massive effect. The traxxas bandit vxl is known for being able to go 70+mph in a straight line, popping wheelies at any speed, and going through grass, sand, water, mud, you name it. It was built to be the ultimate off/on road rc car. The front tires spend 99% of the time in the air and to turn you often need to turn the wheels 45° or more to catch wind to turn the car when on the throttle. With the cereal box aero kit I was making 7 foot radius turns at speeds upwards of 25mph. Something unheard of for this car. I literally could not flip the car either it was so glued to the ground. I have aluminum parts on the car because i replaced plastic parts endlessly when it flips which is very often. So not seeing it flip was a spectacle for sure. I will admit the top speed was greatly diminished to about 50mph, but the car was so stable at 50mph I was able to run the car at full throttle for the full 15 minute battery life and not crash the car once. The car was obviously not designed for continuous running like this and the ECS overheated and almost set the car on fire. Scared the crap out of me seeing my rc car billow smoke in the school parking lot. So the people saying it doesn’t work can stuff it in my opinion. It works REALLY WELL and if you want to try it on your rc car I totally recommend it but add a cooling system to the motor and esc, or stop often and allow it to cool down after very short bursts. Lithium battery fires are no joke and extremely dangerous and difficult to extinguish. So have fun but take precautions and be safe. Learn from my mistakes and know what your parts are truly capable of, and have a plan incase you’re wrong lol. Have a good one.

[@IndeterminateDesign]

That’s awesome. It’s strange how much downforce really stabilizes a car. Did you find that it bottomed out the suspension or made it more unstable over bumps?

[@letsdosomething6691]

@@IndeterminateDesign I avoided bumps like the plague lol because if a hit the slightest crack the front wing would rip off. Once that happens i have to make a new one because the structure of the wing relied on the integrity of the cardboard to not flex. A single crease ruins that. But as far as i could tell bumps really didn’t have any other effects on stability or traction. The suspension didn’t bottom out that i could tell, the bottom never dragged. The car stock has a little less than a 1 inch clearance. I was able to adjust the suspension to get about half that. I was really surprised to find how effective ground effects are. I always thought ground effects was just kinda grasping at straws for every bit of downforce but they probably made up half of the downforce. And it really surprised me and changed how I see aerodynamics. Eventually the front wing did rip off and that’s how I discovered how effective the ground effects are. I think I had a skirt on the sides and that’s it for fine tweaking. I just made the bottom as flat as possible and made the back curve up. Bare minimum ground effects and it worked way better than I had ever thought possible. It was made from a cereal box for crying out loud hahaha. It’s really cool to see how far you’ve been able to take the concept or aero kits on rc cars with all the tools at your disposal. Far beyond what I was able to achieve. Maybe one day I’ll revisit it and get some videos and pics to share with you. I love these videos. Keep at it.

[@letsdosomething6691]

@@IndeterminateDesignat 6:00 you talk about the front wing stalling and the problems that come with that. I’m not sure how you could fix that really well with your current design but what worked on my car was i just had a heavy pitch on the front wing. I think it was maybe 20-25°. I didn’t want to go too high and blow air above the rear wing which was a problem projectair ran into. Probably still too high at 25° though. The front end of my car weighs nothing and i was trying to stop it from popping wheelies. And the body of the car isn’t the most aerodynamic so the more air going above it the better I figured. Because of this I don’t think the rear wing really did too much, but the ground effects, big rear tires, and heavy backend more than made up for that and I had no issues spinning out. In the video of the car bouncing around from the front wing stalling it looks like your front wing was just too flat and the slightest lift in the front causes it to have no pitch at all or even lifting pitch. You could try a steeper pitch in front of the tires. That way air still passes through the middle area and the the rear wing. That should effectively prevent stalling the entire wing by having various pitch angles across it. I can almost guarantee that’s where your issue from bumps was coming from. Besides adding heavy pitch wings in front of the wheels shouldn’t be bad because that air really wasn’t going anywhere but up anyway with the tire in the way. It might cause some extra drag but i think the stability will make it worth it. It would be cool to see if curving the edge of the wing out so the air goes up and around the side of the tire and car does anything for horizontal stability too. All kinds of cool stuff to think about. At the scale of rc cars you can do some really wacky stuff with aero that wouldn’t work on a full size car. You have more surface area per volume but effectively less drag for the scale speed. You can use that to your advantage to make bigger wings with more downforce. It’s late and I’m typing way too much lol. Have a good one and good luck.

[@IndeterminateDesign]

@@letsdosomething6691 That's a great idea. I want to add more pitch to the front wing but I will need carbon fiber rods to support the fenders as the wings support all this. The wing primarily stalls because it comes too close to the ground. It's actually a very shallow wing, but because it's so big, when the car pitches it hits the ground. It really needs more ground clearance. The front end has 2kg of downforce and it drops about 4mm or half the ride height.

[@gp8666]

seeing these videos make me want to build something similar, perhaps i can turn my rc buggy into something crazy like this is

[@IndeterminateDesign]

I think this could work with a buggy, but dealing with the downforce is really hard with a soft long travel suspension.

[@gp8666]

@@IndeterminateDesign yea im well aware, im currently trying to convert my buggy for tarmac racing because why not, i might have to get radical with the rear suspension by switching the spring for a bushing or something to keep it compact and stiff

[@occrc3333]

I love this project. I want to help by buying some of those high speed encoders lol

[@dimitrisath12]

The work is amazing, really reminds me of my FSAE years! Keep up the good work! Any plans on releasing the design ?

[@IndeterminateDesign]

Thanks. I do want to release it but haven’t decided how yet. I need to pull together a fair bit of documentation, which is always the hardest part.

[@gp8666]

maybe you could redesign the rear wing to act more as a twin tier wing with a separate multi element wing for the rear diffuser like on 90s group c race cars?

[@IndeterminateDesign]

I love those rear wings. The hard part is I have to keep the downforce on the rear wing as far forward as possible to keep the car balanced. If I knew what I know now, the tail of the car behind the tire would be much shorter. You can see most of the Group C cars are really short behind the rear tire and slope down as well. This allowed them to mount the wing so that interacted strongly with the diffuser.

[@gp8666]

@@IndeterminateDesign i didnt even think of that, your hypercar is so much alike the xjr-14 being over engineered and so compact its impossible to change or improve

[@GatorGlider]

I'm looking forward to the release of the models! I'd love to attempt building a mold and making the monocot out of carbon fiber.

[@IndeterminateDesign]

That would be cool, and definitely lighter. I wish I could make the whole suspension out of carbon, so it could be smaller and stiffer.

[@GatorGlider]

@@IndeterminateDesign "forged composite parts" - You can 3d print the negative mold, fill it with chopped carbon tow and resin, then compress the mold together to get amazingly strong stuff. kzbin.info/www/bejne/aGaznqSDZ5l7e80 I've used this technique to make stuff for RC sailplanes and parts for Voron 3D printers.

[@amani576]

Is there no way you could try having the one piece control arms cut out of thing CF sheet that may have the right modulus you need for flex?@@IndeterminateDesign

[@IndeterminateDesign]

Possibly I could use carbon fiber sheet bonded together. The key is making the control arms flex when you want them to so you maintain the desired suspension geometry. I need to convince the wife to let me get a CNC router.

[@GatorGlider]

@@IndeterminateDesign if you need something milled met me know and I can do that on either one of my machines.

[@miguelpereira9939]

Following your projects , amazing work! Can we buy the board? I what to do something similar but offroad version! If i can add any input on your amazing work, let me remember that with a normal steering servo, you can easy change the steering direction, but you cant change the speed that direction moves. If you think when you are driving on the highway you make slow corrections but on slow, tight conners you make fast corrections. The normal rc steering servos use always the same "rotation" speed, and this make them unstable at high speeds and impossible to tune. The hardware should allow to get feedback with alot of data, but also control a lot of variables and you are limited on the turning speed of the steering. Torque vectoring will help alot on this matter but its not the solution for everything. Again you are doing a brilhant job! Hope my input helps! (Im a electrical engineer and work alot on 4 wheel drive and steering automatic guided velhices)

[@IndeterminateDesign]

Thanks! I don't have the board available right now. I can email you a copy of the current design. It's definitively a prototype with some issues and flaws. I absolutely agree on the steering issue and the steering feel. I've played a bit with speed variable ratio steering, because the car can just turn way too tightly at high speeds which kills the downforce. There's a whole world of things I could do with fast 2 way communication between the RC car and the transmitter, and having position feedback on the servo, but that's a future development. I'm curious to see how much torque vectoring helps. Everything I read about torque vectoring on FSAE cars said they generally end up tuning the car to have far less computer correction than the models suggest because the car becomes unpredictable and unnatural to drive. I'm curious if that would still be the case with an RC car.

[@falkgerbig7787]

Which influence on aerodynamics has the scale factor, i.e. the Reynolds number?

[@IndeterminateDesign]

I go into some detail on in this earlier video, a few minutes in kzbin.info/www/bejne/pYbHlYGkfK5oe6M The biggest thing is the car was designed and optimized at this size. It would be much more efficient if it was a full size car, but also create more downforce than the tires could ever handle.

[@bruder211]

how much doesn the car weigh in total? im asking becausei am also working on an RC with wings, im just copying the F1 2022 redbull its 1/8th scale but i am a beginner in Cad and i have no experience in cfd so these videos will help me out a lot!

[@IndeterminateDesign]

That’s a great project! The car right now, in RWD and PLA+, is 1650grams. My goal is to keep this same overall weight but add the front motors and ESC’s.

[@wildgophers91]

A random thought that keeps bouncing around in my head is would it be possible to implement some kinda force-feedback for steering? Like it might be super cool if you could "feel" the car in a similar way that sim-racers do.

[@IndeterminateDesign]

It’s absolutely possible and I’ve been researching the topic and playing with ways to accomplish this in an RC car. Overall it’s very similar to what you would have in a disconnected steering system, such as what Infiniti uses, just with a wireless link. There is a good body of research out there, but the actual implementation is going to involve lots of testing and development to get to a reasonably accurate solution.

[@wildgophers91]

@@IndeterminateDesign yeah at first I was like “should be easy!” But I… don’t think it is. How / what do you measure as the signal to the user? Like force on a servo horn?

[@IndeterminateDesign]

Measuring force at the servo arm is the best, but difficult to implement. Indirect methods of measuring torque like measuring amps require a lot of characterization of the particular servo and it’s response, and still wouldn’t be very accurate. You could model the forces acting on the steering from the suspension geometry, and using a lot of math and vehicle dynamics data, recreate the steering feel, but it would leave out a lot. 🤷‍♂️ Things I think about a lot at night..

[@gonuhi]

What free cfd and cad software is the best for beginners like us who wants to be free,exploring the field first?

[@IndeterminateDesign]

I use Autodesk Fusion 360 for CAD. For free CFD, there are not a lot of good beginner choices because in some ways the results of the CFD are only as good as you configured your software. Obviously I use AirShaper because it’s so much faster and easier to configure a case, but most CFD software is built upon a really poorly documented set of software called OpenFOAM. I used a derivative called BlueCFD for a while. It’s very powerful, and script based with no free user interfaces. If you get it configured, you will learn an immense amount about aerodynamics and CFD. There is also an online product called Simscale, and it has a free number of hours that would allow you to do a few simulations. That maybe the place to start for very simple models, and there are great tutorials. I found it did not handle complex surface based models like the RC Hypercar. If you’re a student, you have the ability to purchase Solidworks CFD or Ansys. Both good products, but very expensive outside a student discount.

[@gonuhi]

@@IndeterminateDesign the problem is that my country doesn’t support paid subscription or even PayPal so that makes these useful software and courses hard to access but thanks for the info,I will consider to use airshaper when things get better,so what you are meaning is that cad software is accessible and cfd is not? Okay noted I will now be subscribed to your channel because your info and your in depth analysis are helpful for me to watch,who is a complete beginner and by the way what are the recommended pc specs for running cfd and cad? I am planning to buy a new pc and I will ask a person I know of to pay subscription to the cad software but for me,airshaper is the greatest cfd tool I’ve seen but it’s too expensive for me,which is a bummer but thanks for tuning in and replying!