Driver 61 YT channel if you want to see someone do it for real. hasn't done it YET but preparations are running for a year now. and he is really adamant about that, he has surrounded himself with very smart F1 ppl to transform a Formula car into a specialized "upside down car". he got a big building company to build a dedicated tunnel just for that. I can't wait until he announces the date.
If anyone is interested in fan cars, the McMurtry Spéirling recently broke track records, proving that ground effect is very effective under the right circumstances.
the t.50 uses the fan in a very different way which only produces downforce at high speed and does little to increase the actual downforce of the car. it is mostly to make the car "stand out"
I believe the Chaparral 2J had its skirt mounted to the suspension, not the chassis. This way the skirt stays flat with the wheels, and doesn't move with the body. Try mounting the skirt to the ends of the suspension near the ball joints, and I bet you'll have more consistent suction and longer lasting skirts.
Some suggestions: How about a skirt made from a brush? How about putting the ground effect tray on a separate set of suspensions from the main chassis? One irl example is the Lotus88 One I've been asking myself watching the video is what lead to the choice of a propeller instead of an impeller to evacuate the ground effect tray, as the latter is way better at producing a pressure difference?
@@superbmediacontentcreator my reasoning would be that a brush is flexible enough to deal with rough terrain, while doing a reasonable job at blocking airflow. The brush hair would also be trimmed through usage, by contacting the ground, reducing friction and tuning the system over time. The problem with a hard barrier as we saw in the video is that once it hits the ground the wheels suddenly lose traction, which could be reduced by using a brush skirt. Some hovercraft designs use brush skirts, which is why I thought of it. Granted there they try to keep air in instead of out. edit: I'm not sure where I saw it and cant find it atm.
There is a BBC documentary called "Gentlemen, Raise Your Skirts". About the ground effect cars Williams had back then. No fan but shaped underfloor and the skirts were spring loaded carbon strips that could retract up and down into a slot so they could touch the track surface and follow the imperfections in the track. Check it out if you can, it's awesome if you like those old BBC doc's.
One of my fave quotes is from that, when Alan Jones complains about the ride quality of the car when they tried solid suspension. Frank Williams replies, "perhaps you could sit on your wallet, Alan?"
The issue was you locked the suspension out. You effectively cancelled out the mechanical grip of the car. In turn, you also proved the effectiveness of the design. Double edged sword so to speak. You must have heard of the McMurty special right? If not....bro.... where have you been?
@@deaddirt3214same! The first time I saw it I thought the playback speed was increased. And the car kind of looks like a cartoon, just the way it's shaped.
@@deaddirt3214 haaahahaha!!!! Never can tell these days right??? I saw this virtually PERFECT girl the other day. My initial thought was "meh....A.I. derived imagery. Nobody's that cute." Then i slapped myself in the face and nutted myself on my truck bedside because it was borderline special needs thinking.
If he could find a smoother surface the locked out suspension would work, shifter karts don't have suspension but make plenty of grip. To get it to work on asphalt, he needs to anchor the bottom of the skirt to an un-sprung part of the car, like the control arms. Alternatively he could use servo adjusted skirts and drastically stiffen the suspension. What would work best is a small pod over each wheel with ducts leading to a central fan. If the downforce is acting directly on the knuckle you don't have to run extremely stiff suspension for it to work well.
@@NNFaNRacing Those kart chassis are designed to twist and flex to work as the suspension, they still have suspension, it's just implemented very differently.
The Chaparral did this long before the F1 car you cited. The concept is valid but was outlawed because the fan throws stuff all over the following cars.
@@benkirkland5354 As I was growing up I cheered this and the STP turbine car both of which failed for different technical reasons. Had they foreseen the things that ultimately killed them they would have revolutionized the sector before being simply "ruled off" the tracks. I think the electric boost shows the most promise in the near term for F1 unless that like the Grid Girls it gets banned...
The Jim Hall's Chaparral 2J was also closer in concept to this than the Brab, as the on the 2J had a separate snowmobile engine, so fan rotation speed wasn't a direct relation of 'main' engine speed. More consistent 'suck' across the entire speed range of the car, rather than more 'suck' at higher main enginer RPM.
I'm sure it would throw a bunch of stuff around, but because it mostly made all of its downforce from the fan system if for whatever reason the suction between the car and the track, like a big enough bump or a skirt was broken it would lose all grip and be very dangerous. Imagine it just launching mid corner straight off the track. Great system in an ideal world but potentially deadly in a real world
Fun fact. Gordon Murray (the designer of the BT46B fitted an aeroplanes altimeter in the cars so that it would show whether the underfloor was sealed. The drivers had a problem that the skirt would be damaged and they wouldn't know and suddenly find themselves going through a corner about 40mph quicker than they could without the ground effect and having a colossal crash. So if the altimeter was in the green they could push. If it wasn't they had to back off.
High pressure flexible 'tubular' perimeter skirt, low pressure chamber: Forget the walls, replace the skirting with something akin to a hovercraft skirt, but with the skirting pressurized to keep it inflated. I also suggest a tough material, as it will be in contact with the ground at high speeds.
You're right in concept but there is difficulty with this sort of thing at scale. There are just some technologies and materials that don't scale down well. This is the case with your skirting material. It is very heavy and thick and hard to reproduce at a small size and get the same robust survival enjoyed in a 1:1 environment.
If my memory is correct the seal was made in more than 1 over lapping section so the road contact area could be worn away then slide down to replace it. Eg had a total loss section that lowers as it's warn away.
The original Lotus car had sideboards mounted on slots so they would always adjust themselves to be touching the ground. Your front skirt-board doesn't need to create a perfect seal to the ground. If it's bouncing on the ground it will be slowing your car down. Some of the F1 cars used broom bristles to create a seal.
Love to see this run on a basketball court where the floor was perfectly smooth. That would let it really corner. Seems like for the skirt, some thing pliable but durable like silicone sheet would be good. Great vid as usual!
The part you missed, or couldn’t replicate from the original fan car, was the skirts moved up and down inside a channel in the sidepods so that they maintained the perfect hight to the road all the time, the last time I saw one it was effectively a draft excluder bolted to a piece of plastic that sat in the channel. I’m also fairly sure they didn’t completely enclose the skirts at the front (and probably the back) of the car as that was how they drew the air in to create the vacuum. There’s no way this is practical to do on that size of car but maybe a bigger one?
Actually, he could have achieved this with a spring-loaded frame under the vehicle with a segmented rolling edge. The challenge as I mentioned in a previous comment is that some materials just don't scale well and many solutions add drag from their contact with the surface. Remember the aggregate in the roadway is 1:1 not scaled to the car used for testing. This naturally hampers and intrudes on any of the solutions and improvements.
@@testpilotian3188 Lol it sure does, because we know the Square-Cube law and the exponential relationship between velocity and fluid drag makes "RC Scale Speed" one of those measurements that don't mean anything. It not only affects the material properties, but the physical properties and the vehicle behavior. These RC cars also have a power to weight ratio that is immense compared to actual cars, the Traxxas Maxx V2 for example has just shy of a 1 to 1 power to weight ratio if my quick maths were right (and they may not be since I'm not full awake yet), weighing about 0.2 kilos but making 0.16 horsepower from a 6 volt, 20 amp peak draw. Edit: Actually, its likely far above a 1 to 1 power to weight, now that I think about it. Since those things supposedly draw like up to 100 amps or more, and the motor gets to see the full 4s 16 or so volts, and that's 1.6kW, which means 2.15 horsepower. On a 200 gram vehicle. That's over a 10 to 1 power to weight ratio. Come on stupid brain, work with me today! The rocks ain't rocking right right now XD
You could try to just mount the skirt part of the car to the suspension. This was, it should keep it at roughly the same height off the ground (like a car called the Chaparell 2J)
This is extremely sick, and you pulled it off so well! I have been thinking about doing something like this since seeing the Formula Student car from ETH Zürich use a similar approach for reaching 0-100km/h in under a second. IMO it's impressive how much extra downforce you ended up getting in a straight line on this. To improve the seal on bumpy roads, maybe you could try a 3d printed flexible TPU base with a sort of skirt around it from thin PTFE that is too long and just bends out when the car is further to the ground, but then extends once it goes more above it or over a bump?
I like this concept a lot. Maybe you should try door brush seals for the skirt. First they are flexible, second durable and last you brush stones away in front of the car.
I think sprung segmented skirts would be best, its what Chaparral did with the 2J, and it worked beautifully. The only difficulty is doing so effectively at RC scales.
I'm so glad somebody had a go at this. Really cool project. The original skirts were spring loaded strips that pushed down into the road kinda' like DC motor brushes. It always amazed me that it works at all. It's so counter intuitive to try and maintain the seal between car and road.
the small bits of debris, gravel and overall road roughness at the scale of your RC car, would be similar to trying to drive a formula car on a 4x4 off road trail. perhaps try testing again on a smoother airport runway?
If you scaled up the small bumps and cracks in the road it would be like taking a life size F1 down a gravel road. Surprised it worked as well as it did.
The rubber squeegee from a wiper blade may have enough durability to last. It could allow for a small travel to be added back into the suspension to help with its jumpiness
Great project again! This is exactly my thought for pushing the next level of the RC car speed challenges. Down force with little drag penalty. Also hub motors to remove the drive train issues and be able to use gyro stabilised DTC to keep it straight. Tyres are the only unanswered question.
You should test this in a gym or any place with polished concrete. Additionally, the skirt could probably be made out of overlapping flexible "tongues" that angle backwards and can bend when pressed down. Combat robots often use this as a flexible wheel system that's difficult to damage.
to have the best effect, you have to attache the soft part of the skirt to the suspension triangle, Like this you can keep the skirt to a constent high from the ground. The skirt can be attached on one side to the rigid part (your aluminium board). And on the other side to a bar connecting the suspension triangle ( 2 tubes can be imbricated in each other so that they can slide and allow the suspension to work)
Imagine the ideal track. When you make the care smaller, everything else gets bigger. If everything was smooth, flat, and sticky, I'd love to see an rc car race of practically mini f1.
Although this might be hard to accomplish, but there was a design on the chaparral 2j regarding the side skirts. The 2j was a fan car, but had issues with maintaining proper suction. The car had a mechanism where the skirts would move up and down as it was linked to the suspension, preventing it from scraping against the track surface
Actually one of the first fan ground effect race car tackled the issue of the seal breaking by mounting the bracket to the suspension with the wheels so that it would go up and down with the road so it can keep vacuum at all times The chaparral 2j
Imagine someone was just casually walking on the side of the road and then he hear a sound but he doesn't know what it exactly is and after he go around the corner, a fast tiny car suddenly goes right pass him, he stand there in awe but not even 5 seconds later he feels a sting on his right foot when he looked down, his right foot is gone.
i'm an f1 nut and i know back in the day they had a semi rigid skirt that would bounce inside a receiver style channel, i wonder if you could construct something like that and try t again. despite the porpoising as soon as that fan cut off it was going straight to the scene of the accident, awesome look, need a 2.0 video
12:19 And that's exactly why this was banned in F1 a couple of years later. Awesome recreation, really amazing they were brave enough to try this in manned vehicles.
Very cool idea. Now we need : 1. Formula car 2. Helicopter turbine 3.Gearbox conversion 4+ A lot of engineering Thanks for the video. Very interesting how you scaled down a previous idea and made it work !
the first thing that came into my mind is that you need very flat surfaces to make it work on this small scale, because the roughness of the road creates opening for the air and the vacuum is not that high to compensate.
The F1 skirts they used were free floating or spring loaded - gravity/spring force meant that they were always sealing to the ground but without bottoming out the car or bouncing
An old bicycle tire inner tube, trimmed to fit, would provide a flexible and durable (enough) seal. You could sandwich layers of the rubber so that the lowest point would still be light and flexible, but still offer a certain amount of rigidity. Sort of how they do on air powered hovercrafts. Except you could form the skirts to put force straight down towards the ground, (instead of the "balloon" shape used for positive pressure),since you want a negative pressure. I am sure it would take a little experimentation to get right, but this would allow you to increase the suspension travel and ride height (to prevent bumps from causing the tires losing traction in the corners).
With Can AM cars the skirt height was controlled by the suspension via cables and rockers. This allowed the suspension to do its job while maintaining the necessary skirt clearance.
Just a thought, have you considered multiple concentric seals. The pressure differential will reduce between each seal and result in an overall better and more robust seal.
You need a much smoother surface for consistent ground aero on an rc car. Those bumps it’s hitting would be the equivalent of an f1 car driving down a country road.
I would also like to add that on modern formula one cars, the “vacuum chamber” becomes a lot higher the closer it gets to the end of the car. I can see that your vacuum chamber is a consistent height throughout and it reduces the total amount of possible ground effect because you aren’t making the most of the available area. My suggestion is to cut a rectangle on the bottom of the chassis and raise the roof of the vacuum chamber to increase the vacuum. Another thing that I’ve read a lot on is connecting the vacuum chamber to the bottom of the suspension and replacing the foam boards with a brush material and I would like to second that idea because it is a great idea to keep the vacuum consistent. I would also like to see you use a rubber seal like the ones used for car doors and refrigerators if you have the chance. And another thing, please make the exit for the air parallel to the ground because while you are driving, the small amount of air inside the vacuum chamber is crashing against the rear wall of the chamber before getting sucked out, so might as well replace the rear wall entirely with the propeller to reduce air resistance. This will also give you more vertical space to raise the roof of the vacuum chamber even further and make the suction stronger. I hope my ideas are of use to you, and keep making awesome content!
It might be complicated, but the chaparral's fan car had the skirts somehow linked to the suspension so it stays in the right attitude, might help you with the consistency around the corners. There are so many details about those fan cars and active aero in general, have fun going down that rabbit hole!
After watching up to 13 minutes on this amazing video I recon the low pressure false floor should be connected to the wheel carriers instead of the chassis. That would allow a softer and grippier tune of the suspension and still maintain the seal to the ground, maybe? Williams used something like that in F1 in the early 80's.
Remember that rc cars are still downscaled. Driving on a normal asphalt road would scale up to like a cobblestone like surface. Perhaps a soft, flexible rubber profile could be worth a try. Quite cheap and more durable than the foam. Also, it could dampen bouncing.
Another thing that would be interesting to try would be to just put some drone motors with reversed props on top of the car. No need to worry about a seal and it woukd even work well off road.
I use horizontal uhmwpe strips fastened with 3M VHB double sided tape stuck to 90 degrees carbon strips, to seal the floor to the ground on my race car. We don't have electric fans, so have to rely on the low pressure generated by the floor/diffuser to pull the car down to seal against the track, which only works above 60mph. The uhmwpe strips are low friction, and easily replaced once they're worn down.
Make the skirts to seal the floor with a bicycle inner tube. You can cut in the U shape and create a double wall. This will copy the profile of the surface. Another tip is not to set the suspension so hard.
Great job!!! To overcome the weight issue - powering the fan by the differential/ an output shaft would be ideal. Might be complicated but it bet you can pull it off!
I have been watching RU-vid since it began . This is the ABSOLUTE BEST video EVER. Thank you SIR! Society needs you to be a teacher. The education system in every country needs to hire you as an online mandatory teaching lesson.
when i first heard about this formula 1 car i had some ideas of my own but testing them on a life size car was never going to be in my price range so you have given me a good idea, thanks
my guess: since you have independent suspension, make a 4 part skirt with a flexible cross, so wheels can still independently move, and the skirt gets closer to the road.
For the skirt you could try some flexible rubber like a hovercraft, or perhaps some brush material like a paint brush. Try soft or hard bristles and see if there's a difference. I imagine you want something soft enough to adjust to the road surface without losing too much air pressure, although losing some air pressure might be preferable to losing traction on the tyres.
What if you use springs on the skirt of the car forcing it to stick to the ground. This would also allow you to add extra skirt to sacrifice to the ground.
Might want to try brushes next time on the skirt. Use them for weatherstripping and they are way more sealed than you'd think they could be considering they are just bristles. The way they conform to the rough surface more than makes up for the losses between bristles.
the reason why the car keep bouncing was because of proposing it happen mainly on grown effect cars Porpoising is essentially the car bouncing on its suspension (the wheels stay grounded), an issue that can be a combination of suspension and aerodynamics, or simply a bumpy track. Running the car closer to the ground or setting up a stiffer ride can lead to porpoising,
Great video yet again 😃 The original F1 cars used thick rubber to seal the edges, but they used springs so they could move a bit through the undulating surfaces. Might be worth looking into 😊
If you can somehow able to attach the skirts to the wheelhubs. Make it part of the unsprung system. This would allow the skirt's ground clearance to be more consistent.
Imagine the rear edf installed on 1-axis servo controlled mount to provide some thrust vectoring. Ofc it would require some flexible sleeve to keep ground effect low pressure -side from leaking. Or maybe some active aero added to this car to help with cornering stability, and top speed (with drag reduction system). I’m just throwing some stupid ideas, but keep up your awesome work! 🙂
A softer skirt, like one printed from TPU or made of rubber, might help. Something that can take the impact and deform to the shape of the road, rather than bouncing the car off the wheels. Also, i beg of you, if you're already going down this path, consider adding a second set of steering wheels at the front like the famous Tyrell P34 :P It might genuinely help with cornering.
You should take a look a the Chaparrall 2J, which was the first fan car. Jim Hall has a sort of interview/video where he showcases all the cars he designed and has extra info on the 2J and how it works.
The skirts on F1 cars were moveable pieces slotted into the sides which would allow for the sealing over bumps. I'd love to see you build more on this idea, maybe trying more skirt materials, or even changing the fan duct shape.
Try using flat framing from nylon or teflon to keep the contact with ground. Keep that framing suspended from wheels using some impregnated fabric. Maybe even try using some sort of secondary thin short strips of fabric on the framing to compensate for smaller imperfections on the road.
you will find like in the lotus 88 the skirts are connected to the suspension arms so the shirts always remain at a set point above the ground and that way you putting all the load to the tyres and not loosing ground effect in the suspension.
