241% More Grip with a Fan Car and Ground Effect
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- čas přidán 13. 05. 2021
- Tesla Roadsters and the Tesla Plaid model are have amazingly fast 0 to 60 times, but I've built an RC electric Fan Car that I think can actually beat the real deal. In this video we will race the Gordon Murray Inspired Fan Car against the Tesla to see if a toy can be a Tesla.
Parts used for this build:
Original Car (this was HEAVILY Modified):
amzn.to/41cLE1L
Upgraded 6s Motor:
amzn.to/44Hjqzd
Ducted Fans and ESCs:
amzn.to/3NRUG1o
4s Batteries:
amzn.to/3NRV8N8
Silicone Sealing Strip:
amzn.to/42zO23H
Differential Build Kit:
amzn.to/42j0mWm
amzn.to/42ztclg
These are affiliate links so I may get a small commission from these at no cost to you. - Věda a technologie
A few days later the SpaceX package was quoted as having a 1.1s 0-60 with those cold air thrusters. Got your work cut out for you! Awesome work, this is already bonkers.
He’s also been promising full self driving for how long? I’ll believe that 1.1 seconds to 60mph when I see it.
I was going to table pushing for a better time for a good while then I saw this announcement too lol.
I'll need a new motor/esc combo to fully get there and that's a couple hundred...but I know it's possible to beat the 1.1s with a rollout...maybe even straight up
@@EngineeringAfterHours the gains you got just with the tweaks you did already were huge, I wanna see this showdown happen some day haha
@@Dave-so7sf the beta that's out right now is arguably the closest thing to level 4 or 5 we'll see in the wild for years from anyone, that isn't arbitrarily limited to x roads.
It's not that we're not there, just that regulatory approval will thankfully be a monster to acquire, promises notwithstanding.
Wider tires and get rc airplane motors 😮 that thing will be UNSTOPPABLE.
Non-sensored brushless motors have to move and twitch a little so the ESCs can detect the rotor position and start firing the motors properly. That's possibly your startup/launch twitch issue - until the car twitches and moves a little the motors can't go full power.
Sensored drive motor might be the difference.
Was going to say the exact same thing. It is the sensorless motor causing the stutter
Yep sensors help with tall gearing for take off to
you're telling me he has turbo lag on an electric car? makes sense
That and this motor and esc is very bad for studders
Glad to see this comment; a sensored motor/esc will allow for much better phase resolution and virtually eliminate the stuttering from zero RPM. In addition, a sensored setup will allow for more precise timing adjustments resulting in measurable and more meaningful adjustments when compromising mid-range torque versus total efficiency on the last leg of the curve up to 60 mph.
I see people have already commented about sensored motors, you should definitely look into them though. It will most likely eliminate all the stuttering off the line since the ESC will already know the motors rotor position.
"sensored motors for the win!"
~me, a guy who drives a max 8 sensorless combo
WOW HE USED SENSORLESS MOTOR?!
There is no much performance left out on the table omg!
Using a ground effect to improve traction is a great idea as otherwise you're limited to about 1G as the traction simply cannot exceed the weight of the vehicle. You do mention around the 10 minute mark an intention to throttle the fans to reduce skirt friction at launch, but throttling the fans with the motor will never work asnot only do you need to overcome the inertia of the fans and fan drivers once throttle is applied before you can start generating any downforce at all from the set up, but you also have to overcome the volumetric displacement within the skirt. My first thought when you mentioned the desire to relieve the ground effect for initial takeoff was to actually stage the ground effect system with an idle stage of maybe 30-40%, and then throttling it with the main drive as this will already have your fans in motion relieving the inertia problem, and starting you off with a mild vacuum beneath the skirt helping with the displacement issue.
Another thing that could be done to reduce the displacement beneath the skirt is to fill some of it in with more material but that would both increase the risk of bottoming out and add weight that has to be accelerated and as such wouldn't be ideal.
Not going to lie though, I'm stoked to see a ground effect system in use here, as I've been thinking the same thing for a possible challenger to the roadster if I ever had the money to build it. I'd be using a small gas turbine to generate power augmenting a small battery set-up to save weight and provide huge amounts of current to the drive motors when needed, whilst sucking air from beneath the vehicle and providing a small amount thrust to help get things motivated
A sensored esc and motor would help prevent that starting stutter
Agreed and a stronger battery.
Back in the mid 1970's, my high school replaced the old cinder running track around the football field with a RUBBER track. Maybe check some of the schools in your area and see if they have something similar that you can run on. Either that or maybe a parking lot that's recently been repaved with asphalt, to smooth out the ride. Don't know if directing the air from the ducted fans back in a horizontal line would help much, unless you're using that thrust to provide some of the downforce.
Thanks for this series. I really enjoyed this!
Watching This makes me realise how much I want an rc car where wings pop out and you take off and fly it.
The drive shafts that you are running are an upgrade from the standard ones, yes, but not the most bullet proof option Traxxas provide. Search for the Steel Constant Velocity Drive Shafts available for the Slash 4x4: CVD part numbers - TRX6851R (Front) TRX6852R (Rear). Great vid btw- Love seeing 1:1 Automotive Engineering principles being applied to RC!
watched 2 vids randomly. Functional & explanative genius rc channel kudos!
I would love to see how much faster or would run on a smoother surface like a school gymnasium or a roller rink or inside a big warehouse. I imagine the fans would work better giving you better traction and hopefully quicker times.
YESSS
Low traction surfaces though. He'd be better off running on a well maintained drag strip.
I wonder if the sticky compound most at the start line would be too much for the drive train to overcome though?!
Nice project! I really enjoy watching it!
really enjoying your content, keep it up👍👍
Thanks! Im Looking forward to more free time over the summer for more projects
Hoooo that's wzup! Nice man. Definitely subbed up ✌🏾
Awesome 👏 you have a new subscriber, loved the application of math and your clear and detailed explanation. Time to look into the rest of your work. 🏴👍
Thanks for the kind words!
Impressive to create a fast car that is NOT traction limited. Would love to see a even more powerful version. Seems like active low pressure underskirt is a high risk high reward strategy, just as in Formula 1.
Your channel is really underrated, great video!
After your active aero videos and now this, I keep wondering how practical it would be to get some kind of active suspension system setup
I wish I had that for this video because the suspension has to be so stiff for the downforce
@@EngineeringAfterHours can you make tamiya mini 4wd aero dynamic effect? since the release aero body and aero chassis as well...
@@EngineeringAfterHours i can not find it anywhere... the best video is just blowing dry ice smoke in wind tunnel to see how air flowing. i feel not satisfied. sorry for bad english..
stunning work
Fastest outdoor vacuum I ever seen
Just subscribed! Sweet rc !
God bless
Dibs on that rc when you're done with it. 😉
Great video!
Serious suggestion, can you mix the downforce engines and have them spool up as the car accelerates? As to reduce the stuttering and as the car starts to approach 3G the fans come on full.
This was done on a Le Mans car in the 70s, it was the chapparral 2J, it achieved such cornering grip that they banned the use of fans to create downforce. Funniest thing is that I only know about this because i spent 1000s of hours playing Gran tourismo as a child and read through every cars bio and history haha
That car was one of my inspirations for the project.
Gordon Murray had some success with full size fan car. His new T.50 looks to be quite amazing.
But its not full fan car per say. It just cleans boundary layer in diffusor and prevent stalls at higher speeds. And makes using steeper AOA of whole floor.
Great video, and damn this channel do deserve teh subs :D
this is nuts, my friend has the xo-1 and i thought that was crazy
is it just me or the track seems very rough? is that on purpose for more traction? it seems that the car is bouncing a lot on the cracks
About the part where any transmission bits get shredded, I can only quote Gordon Murrey talking about BT46B: "Our driveshafts really didn't like our 2G starts."
2:01 Giving happiness powder to the car
This is glorious. You’ve earned yourself a sub my friend 👍
Thanks!
I have seen Just 2 of your video, and deam, you deserve waaaaaay more than 5k subscribers, good luck whit this Amazing channel
Well done. Loving your channel. I like how you show the trial and error in your video. I would recommend a castle MMX8S esc and motor sensored set up , that will help eliminate stutter on your start up . Castle systems are much more efficient. And again look at BSR foam tires.
Thanks! I definitely want to get a castle sensored setup for this guy
Wow this is good stuff
Dude seriously? I mean you're not serious really? If i didn't think the world was living in a dual, imaginary world already - This really takes the cake.
The stuttering at launch looks like something us drag racers deal with called "wheel hop", generally suspension and tires (changing from low profile like you are running, to large flexible side wall drag tires) are the solution. If you look at some of the slow motion launch clips, 12:30 for example, and watch the tire and road surface you can see the tire is actually slipping, more more precisely slipping for a fraction of a second, getting grip again, then slipping again. Look up "drag racing wheel hop" and you can get some good analysis of it for full sized cars you can probably apply to to your model but I would put money on that being the cause of your stutter at launch.
Did you also notice how much flexing happens in the suspension components further worsening the wheel hop situation. You can see the wheels moving back in forth in relation to the chassis. Traction bars up front and trailing arms in the back would definitely help with wheel hop. Im not convinced its a motor issue as alot of people suggest, as much as it is a suspension/tire issue.
This is wrong. There may be some wheelhop but the stuttering is a non-sensored brushless motor characteristic we call “cogging”. Someone had a decent explanation in the comments.
Awesome video mate, loved every second of it.
I have a few suggestions which will definitely help to reduce your time further.
I would recommend getting a Castle ESC + Motor since they are sensored and have more power, this will eliminate all the stuttering at the low end. Switch out the Arrma tires to GRP S1 tires or even foams if you can find them, the traction is way better on those. For batteries I would look into Chinahobbyline G+ 70C. These are the best batteries for value in my eyes.
I have an Arrma infraction and I managed a 0-62mph time of 1.79sec without any ground effect so I'm confident that you can manage a sub 1.4.
Good advice, I'll look into the GRPs and the batteries as I've never worked with either of those.
@@EngineeringAfterHours You can usually find some discount on the batteries as well :)
Great great build!!!!! THE “STUDDERING” on takeoff is called COGGING!!! It’s because you’re using a NON SENSORED kv motor!!! By going with SENSORED, the motor can begin acceleration from a dead stop IN AN INSTANT without “cogging”…. Sensored is a feature that allows the esc and motor to communicate with one another soo that the esc can KNOW the pol positions of the motors magnets and and distribute voltage in the proper sequence…> NON sensored motors is like a blind man with a walking stick, it needs to find its way…
Kool man. Foam tire will help with grip but this is a cool concept.
Really really dope.
This video is great sir! I have a question though,what's the part # for the slipper clutch eliminator? Thanks.
The one I used it made by hot racing. I don't know what the part number is.
When you test the suction of the fan, the suction could be more powerful than you calculated as the fans might produce more thrust with some airflow, compared to pushing static air.
idk maybe
Well done video.
thanks for sharing :)
i love that the roof of the rc car is literally a dirt bike helm
Quien viene de Wefere? 👀
Intake guide vanes for your edf's would help increase vacuum with only trivial weight consequences. Nice work, huge Fan.
I live in the same city!!!!! It'd be awesome to watch this car go some day!
I have been looking to do similar on one of my arrma cars, where did you get the fans and more importantly the fan housings from? Thanks
The fans are 50mm EDFs from amazon. The housings I had to design and 3d print myself. They needed to be pretty form fitting for the packaging size I was working with
@@EngineeringAfterHours Thanks so much for the fast reply. I don't supposed you have the 3d files that you could send me by any chance? If you look at my latest video you'll get an idea of what I've got planned for the same setup. If you were willing to part with the 3d files my email address can be found under my 'about' page on youtube. I've watched this video 3 times so far this morning! I am thinking of custom making a chassis for my infraction with just this idea in mind
@@DriftomaniacsRC haha awesome...planning for it on the infraction? Where can I send you files?
@@EngineeringAfterHours Hi there's a link on my youtube homepage if you click the 'about' tab it'll show a link to my email. Much appreciated just watching your latest 'last' video!
How much downforce do you generate via relative wind at speed? Can you reduce the under tray fan speed past say 40mph to keep your acceleration up.
Bro you naild it
Cool!
Tip: You can probably get better results by using a better car to start with. Check out 1/8 on road racing cars, like the Serpent 989 lipo version. That is serious race stuff and use way better materials and part design. Also the tires (foam) they use give much more grip. Especially if you use the softer ones (low shore values). I bet these cars do 0-60 in 2 seconds in standard race trim. Now add your fans. And maybe put some weight at the right place, on the front? Also, use high capacity and high discharge rate batteries +8000 mah. Lubricate the the tires with tire sauce to make them even more grippy.
awesome!!!
Can pull down power on the fans after launch? Locked difs would help too
Thought about a lcg chassis or shortening the shocks to have it ride lower?
Lcg chassis was ordered last week:)
Could the stutter be from the drive shaft twisting under initial torque load?
I think its cogging of the motor.
Amazing
loved it
SOOOOOOOOO SICK!
Brilliant, yeah I was going to say to take the camera off the back, great experiment 🤠
Will a heavier car be better for that initial traction and be more stable. Seems power is not an issue. Larger tires?
No, this car actually is power limited and not traction limited. A heavier car will make it worse. I'm going to rebuild with a little less downforce and drag, while moving to a better motor setup
I did near the end see a scale . A scale below each wheel could help balance the car better . Awesome work . . .
Is it possible to use conventional drag racing and somehow involve a trans brake to deliver torque faster than what the ecu can deliver?
It's probably possible, but with the upgraded sensored motor on the next build...I didn't need more torque.
7:05
Gordon Murray and his Brabham BT46 fan car: ".... am I a joke to you?"
Awesome content 👍
Actually I think the front wing does help with aerodynamics !
It probably does give me a little downforce but it's got so much from the fans that I don't really count it
Have you tried softer springs on the rear and add a wheelie bar so your not spinning as much
Cool!
Just out of curiosity why not use the Traxxas low cg chassis and center differential?
I've got one on order. I just didn't include it on this build because things start getting expensive fast so I try to set a Max budget for each build. This one was already over $400 so I needed to break it into a few incremental attempts to fund everything.
@@EngineeringAfterHours oh gotcha. I wonder if Traxxas would help you since you seem to use their products allot.
Awesome
I just know this video will eventually blow up, possibly when the new Roadster releases
what if you put a button or some other trigger that can pre spool your fans at an idle speed but theyll still be attached to the throttle so they can spool up to full when the car needs it
One question. What is the reason to put the batteries and fan controller near the rear axle?
That was where I could cleanly fit them them as low as possible. I wanted the CoG to be low, and they needed to tuck under the body I had.
The stuttering at the start happens because of block commutation (how the esc switches the motor). A esc with Field Oriented Control has significant more torqe from a standstill (a VESC for example). Also VESCs support up to 12s voltage = moar powah babey.
Interesting...this can be done on a sensorless motor?
@@EngineeringAfterHours yes, it also Supports sensorless Motors. Although I dont know how good it works without sensors.
all sensorless brushless esc's rely on back emf (voltage induced by the magnets spinning by the coils) to sense the position of the rotor in it's rotation
sensored motors use additional magnets and sensors to directly measure the angle of the rotor
that has nothing to do with the commutation, which is what type of alternating current is used to drive the motor
the easiest type is square wave
most esc's use trapezoidial, there are a few that do sine wave commutation at startup and switch to trapezoidial and even fewer do full sinusoidial
the more rectangular the wave is, the more power the motor will produce, at the cost of smooth rotation
choppy rotation is most noticeable at spoolup, which is why some switch from sinusoidial to trapezoidial (smooth start, power when already going)
another factor is what pwm frequency is used to create the ac
the higher the frequency, the more efficient the motor is
lower frequencies create more power
some esc software use the rpm of the rotor to define the pwm frequency
Vesc also supports sensored motors, and has done high current stuff specifically designed for loaded start applications. I would definitely recommend checking it out.
Yeah I've been fighting cogging on my new stampede setup. My maxx does it with my bigger tires too sometimes
Have you extended the pan vacuum box forward between the wheels ? I think extending a small portion 2"x3" approximately will decrease the off the line vibration . You seem to have plenty of vacuum, and distributing the vacuum will help with other factors of load on take off.
Even if I wasn't a mechanical engineering major and a RC enthusiast, I would still love this. Have you looked into swapping out tires? I haven't checked out your other videos yet but I tried GRP tires on my Talion V5 and instantly swapped to something else because of the traction.
How do you record the acceleration and velocity?
Sky rc gsm020 and the gopro
Wow, this inspires me to build an all wheel drive electric vehicle, directly coupled to a turbo-jet that drives a big-ass three phase alternator and the inlet to the jet a partially regulated draw from the underside of the vehicle through a FOD trap. I just need a sponser with deep pockets that's all. LOL
Love it
This is awesome. You should try and implement all this on a Arrma limitless.
Should the 1ft rolllout be scaled down to the size of the RC?
No, you would only scale that if you were scaling speed down as wel
Do you think this is possible with the Traxxas xo-1?
Yes, but as the weight of the car goes up. You needuch larger power plant, though the 1717 in the X01 may be enough
Couldn't you have just used wider wheels and tires? And should you turn the fan off or lift the skirt right after launch?
Wider wheels doesn't increase the coefficient of friction, and you need the fans on the whole time to generate the downforce required to get over 2Gs of acceleration.
Try angling the fan output more towards the back to see if that helps with more forward acceleration.
Have you thought of using a sensored motor instead? They have less cogging at low rpm. Great video, like the level of details 👍
I would ditch the large suction plate at the center for a smaller one ahead of the steering wheels (centered fan blowing straight up) and use it as front spoiler also.
The propensity to lift the from during acceleration will be highly reduced by the force being applied at a longer distance from the CG of the car (near center of body).
A smaller suction plate ahead of the rear wheels powered by 2 smaller fans blowing straight up would also increase downforce mid body.
These smaller suction plates will reduce weight while still applying the same dynamic down force load.
My 2 cents. :)
Will the go pro just drag it back by a lot?
It is a reasonable amount of the frontal area so I'll try without it next time.
One thing to help stop the shuddering at the hit is braid the brushless motor wires together works wonders
Yep...version 3 finally went brushless.
have you considered modulating the fan once you reach a certain speed. Maybe the additional downforce is not needed and may be creating drag?
If I had a small motor dyno I may be able to reduce downforce when I'm power limited, but I don't know of one that works for my setup
Take advantage of the fans, u could add a blown diffuser to the car giving it more downforce and even thrust. Cool Video!
The stutter comes from tuning.
The start power on high is not helping you on low end torque. It would be better on the car if you turn start power to Low and timing to zero. Believe it or not you would gain more ground for what you are trying to achieve by changing the 6s into 3s parallel. change the 32 pitch gears into Mod 1 gears.
A 40 spur would change the whole game. As you increase the pinion size you will have less spin or wheeling. All though it would be much easier on a 30 shore contact foam tire to absorb the bumps in the rough road and create maximum grip...... since you live somewhat around McKinney (Traxxas) I would recommend the rear tires that come on the new drag slash. it's a ultra sticky slick tire. But only on 3s. I live in East Texas and work in Southern Oklahoma. I drive by Traxxas every 2 weeks on my way to and from work. If you have any other questions feel free to give me a shout. Very cool video by the way. Interesting to see the science behind it all.
You should pick up an older 1/8th scale HPI nitro car and put an electric motor in it. Those were designed for the kind of speed and HP you are trying to achieve. The Toyota LMP car I have was 70mph out of the box.
Slash 4x4 is 65mph stock. It just takes longer to get there.
What kind of rubber/material do you use for the skirts?
This was just silicone wiper seal
@@EngineeringAfterHours thanks for the info! I’m actually looking into doing a project like this, but I am going for a replica of the chaparral 2j!
@@Alex-vi5kp that was one of my inspirations for this project as well. You can see a lot more of the design process on the first video I made
@@EngineeringAfterHours yea I watched your videos already. Pretty cool stuff man!
@@Alex-vi5kp if you make it work let me know! I'd love to see some other cars like this
Do what they do in the Japanese mouse competitions: 4 quad props set up in reverse so air is pushed into the air and forcing it down that way. Your system depends on getting a decent seal between the skirt and ground, if the car lifts, the seal is broken and there is no longer downforce. The props would give constant downforce without relying on a seal.
We could definitely break the internet with a collab 😤
Hah you have some fun videos. What state are you in?!
@@EngineeringAfterHours thank you! I’m in New York
@@MikeStallone ahh man that's pretty far from Texas...gonna be hard to collab. Let me know if you have any clever ideas.
What your experiencing at launch it's called cogging. It's due to the sensorless brushless setup and the gearing you're running. When the sensorless system first starts up it does not know the rotor position or direction and is basically guessing. When geared very high the motor cannot spin quickly at the start so it stumbles back and forth trying to figure out the position and direction. The larger the pinion you run the worst this gets. This can be resolved with a sensored brushless system.
We've got that fixed for round 3! Stay tuned
I was telling another rc speed run channel to do this a couple years back and everybody laughed. Thanks for making it happen!
Hahaha love it when the gopro flew all over the place
what gear ratio are you running
:edit the studering off the start is the slipper delete
Several in this video. All the way from 19/54 to 24/54.
Add cap packs to
the imperial math makes my head hurt
Are you going to do any test on different track surfaces, like maybe a velodrome?
That would be an awesome surface to test on. One of the challenges I have with testing is that despite it being a "toy"...it can be incredibly dangerous so I need a ton of space to test safely. Otherwise if the throttle sticks or something...its 8 lbs of metal and plastic going 70-80 mph.
I was wondering about this too. It seemed like some of the bouncing around and dragging the skirt would be fixed by driving on a smoother surface. You would also have less traction on a smoother surface probably so I don't know how much it would help.