RC Top Speed Record Car Prototype V1
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- Опубликовано: 9 фев 2025
- This is an initial prototype for an RC car aimed at setting the 4 cell speed record.
All the CFD for this car was done using AirShaper. Check them out here:
airshaper.com/
#3dprinting #radiocontrol #speedrun
Interesting design as always. There is a guy in Europe who made a high performing streamliner with no steering. Each wheel has a drone motor and the control logic allows steering sort of like a tank.
The car performed really well and without axles you can do wild designs.
Thanks. I like trying weird things. I'm going to try and iterate through a bunch other design ideas that maybe more practical.
I really thought about individual motors after I tried torque vectoring on my RC Hypercar. I could easily change the body on that car remove drag. I wish they didn't have the single motor rule for the 4S class.
@@IndeterminateDesignyeah I say build what you want then worry about the class later. There are GPS based leagues. ROSSA is old school and no one in the US is following their rules or using time traps.
Interesting project, do you have the name of the guy or his RUclips channel please ?
(Something) Eng. Look up the beast it didn't go to well for his bigger car.
Very nice presentation of the CAD and project.
I like the explanation too.
Great work.
Thanks for the kind words. I'm really enjoying putting this project together!
Cool video. I like the detailed analysis of your design process. Good luck with the next version(s).
Rear wheel steering worked amazingly well for Thrust SSC, I think its THE way to go.
Only difference is driving through the front wheels as opposed to having a jet push the car which allows the front wheels to "freewheel" which does not interupt tracking in a straight line.
But I still think its definitely worth pursuing.
Thrust SSC was what made me think of this approach. Unfortunately rear steer is banned in most full size land speed cars. I don’t know if Thrust SSC used some kind of gyro stability to help it track straight.
Go watch this interview with Andy Green regarding the Thrust SSC program and the struggles he had with the rear steer system. It was border line undriveable. There was no gyro. I'm not sure you can make it work for a fast RC car, especially since there is no driver feedback to feel what the car is trying to do. ruclips.net/video/Flm95WwYLgk/видео.htmlsi=xlUn7W7My1-5GvdD
Hey! I always love seeing your videos pop up in my feed, they're always top notch!
Suggestion: Have you considered "gearing" the tail-fin? Instead of using a lever arm connected to the servo, having some kind of "rack & pinion"-esque thing, which could either be integrated into the rotating section of the fin, or some kind of reduction-gear stack (xtra weight too)? Unless the servo linkage doesn't really cause any aerodynamic issues... just something I thought about. Great video as always!
Thanks! I've thought a bit about a rack and pinion, and a 3 gear system an idler gear. I even did a couple of designs. But for one of the few times in my life, I stopped myself and decided to keep it simple to see if the rear steer will even work. The steering arm sticking out does look bad, but it's actually very little drag.
Good luck with your project. It looks very interesting.
I 'think' that drag reduces at the square of the scale, so that's another way of saying that the aerodynamic drag of bodies is far less of a consideration at smaller scales than at full size. As you point out, the running surface is MUCH rougher in comparison than for full size cars. You're effectively hitting lumps and bumps that are 10 times the relative size, so suspension and stability over rough ground is probably more important than aero. The reason that most speed cars use 4wd not FWD is that you don't have a great deal of time to accelerate into your speed run because of radio range restrictions, and (in many cases) loss of sight of the vehicle's orientation (can't tell which way it's pointing to correct steering). Again these are not issues in full size speed cars so that's why this isn't an issue for them. Ideally you want as much grip as possible so you can get your power down fast and early.
Very interesting project, keep it up !
You should spend some time at the Bonneville saltflats and get an idea for what works aerodynamically. You will learn alot.
I so wanted to do that. I was there in 2023, but everything was cancelled when the course flooded.
Great stuff!!
Thanks! Glad you enjoyed it.
The reason many race cars are real wheel drive is because the center of gravity is high and when they're accelerating the weight shifts to the back, no matter how far forward you get the weight on the vehicle. I always figured people designed RC cars that way for the same reason, but the center of gravity can be shifted low enough that it shouldn't be nearly as big of a problem
That’s a good point, I didn’t think about that. All of these RC cars have their CofG below the axle line, I think it’s about 25mm from the ground for this car. That would be like 5” from the ground on a normal car.
Weight at the front and aerodynamic drag at the back. Like a dart. Will want to go straight. You could incorporate gyro stability aerodynamic surfaces.
This design is so cool! You should add down-force on the rear wheel as well. It really is interesting to think about how much acceleration is required for this record.
Thanks! I think the consensus among several people is that I need some sort of horizontal wing on the rear for stability. I’m going to try a few different tails for V2.
Awesome Video, can't wait for V2! Just a thought though, look at the RDS (Rotary Drive System) for the tail, it has some serious packaging and strength benefits that i think you could leverage. The systems was used heavily for sail planes and will eliminate your control horns and the additional drag while adding mechanical advantage.
That’s awesome. Thanks for sharing that. A screw drive would be nice since it’s not back drivable and has such a large mechanical advantage.
You can use 2 drive motors that can steer the car without having the rear wheel steer to keep the car straight or turn. The gyroscopic forces from having 2 separate motors driving the front wheels can keep the car straight and you can use a gyro with it. I have seen a video where a person used 2 quadcopter motors as hub motors and got up to 180 mph I think with it tracking straight as an arrow.
I thought about this and talk about it a little in the video. It’s mainly a rules and weight thing. I may decide to not follow the rules and then I’m wide open to use 4 individual motors. I used torque vectoring to great success in my RC Hypercar.
Maybe instead of a tube to connect body to tail, use a long flat-spring. Incorporate the suspension into that piece. Flat-sping because it is stiff one direction. Though there are many ways to incorporate a suspension in the 'connecting tube'.
You want to minimize unsprung mass because it causes very undesirable behaviour.
That’s an interesting thought. I like the idea of just using a carbon fiber rectangle to give it some compliance. I thought about even trying a mass damper in the rear pod.
Do the rules prohibit any sort of rocket power? Because you got a very short track, have you thought about active cooling?
I'm thinking a CO2 cartridge in the nose blowing past all the components and out the back.
I think they just put you in a different class. They have rocket powered and jet/edf classes. I’d love to try a CO2 cartridge in the tail as a brake system.
That pavement looked like the moon’s surface, it was quite rough.
Awesome Video
Take a page from the Chaparral 2J suction cars. Add a suction fan to get your downforce and use the exhaust for additional thrust. Then you can clean up your profiles even more.
Can you make the rod of the body flex only vertically as well? Might help with the rear suspension rate.
I think that is definitely possible. I need to play with some different carbon fiber tubes to see how bendable they are.
Active aerodynamics.
It's not a car, it's just a wheel powered aircraft that doesn't take off.
ArduPilot is your friend.
Edit: I should have waited more than 10 seconds to make a comment. 😶
Interesting stuff, I am starting out on my first stream liner, mine will be less technical design and more test and see 😂
I'm just fascinated by the whole thing and look forward to updates. Have you ever looked into Nitinol based Servos? I got some wire yesterday and was just watching some different videos on it. It seems like it might open some interesting concepts. You could for example make a spring and let forces deform it, and run some amps through it to bring it back to its original shape.
Might be an interesting rabbit hole if you haven't looked into it before.
I hadn't seen the nitinol servo before. That might be super useful for controlling a parachute release or a separate flap for an airbrake.
Idea: steering mechanism: you could connect the rear wheel pod to the main body from both of its sides with hinges and 2 rods. As long as the forward ends of the rods are attached wider, the contact patch will shift outboard when steering. Also it would get rid of the hinge in the rear pod, possibly improving aerodynamics.
That’s interesting, kind of like how a rudder works in an airplane?
@@IndeterminateDesign not really
@@IndeterminateDesign I uploaded a video on X but YT apparently won't allow cross site links in comments
@@IndeterminateDesign it's the post on 16th. @koskelapaulus
Go look at the Carbinite LSR program. I think that shape will be much better and you won't have the rear steer issues. The full scale version was involved in bad crash caused by a rear tire failure, but the testing runs showed massive promise.
Carbiliner was a big influence for this design. If this design doesn’t work out I will most likely switch to something like that car.
Good Work . Very interesting. I dont Know why but from my gut feel i would angle the fronwheels inward like Highspeed cabin road cycles do. Maybe you should get a little inspiration there.
That would be cool. I had a hard time finding RC driveshafts that would fit these motors. Unfortunately the solid axle doesn’t give me much ability to change alignment.
For positive aerodynamic stability you want the majority of wetted (surface) area behind the CG. I think you will need a lot of nose ballast to achieve that with this design.
I talk about this a bit in the video, but the center of pressure is almost 160mm behind the center of gravity. I actually have too much weight in the front, I have 82% on the front wheels which makes the rear a bit too light on the bumps.
@@IndeterminateDesign I have a hard time believing where the CP is, looking from the side of the car, with all of the wheel fairings/body compared to the rear, it looks way more forward to me,,,?
lock the rear, 'steer' it with torque distribution, like a skid steer (or tank, or dozer).
it won't need to turn sharp, just go straight. It is much simpler to do that with two motors!
my dad and i have built a few rear steer trikes, our biggest issue was getting the back wheel not to hop when turning at speed. all of them hopped the last one hopped the least but at full speed it always hopped with any steering input.
Great project. Alos like your GPS mesuring with the webpage on the esp. Would be verry interessting how this is done?
Very interesting. I know it will be a simple programming but I think it is interesting that part of the programming.
I can talk about it a bit more in the future. I’m planning on creating a PCB and adding some more sensors in future videos.
@@IndeterminateDesign Look at the M10 gps, much smaller/lighter
I am looking at your rear steering mechanism, and thinking you can do away with the external servo horn entirely if you allow the pivot to be in line with the servo output. In your speed runs, the steering position will always be straight or near straight while under way, so you could save some weight and aero drag by doing this. I also suspect that above 60mph or so that most of your steering authority comes from the aero rather than any wheels that you would be using for the rear.
Okay, hear me out
put the steering servo behind the steering wheel, and the servo shroud should be a tall vertical stabilizer, above the airstream of the body; putting this weight behind the wheel would give you the proper weight distribution as well as allow far better geometry for the servo. I think the vertical stabilizer is kind of a must have.
That’s something to think about. Would the servo be above the wheel? I thought about having it behind the wheel but because of the airfoil shape the fin would end up being huge.
I didn't watch the full video, but did you try putting a small horizontal tail on the rear wheel to keep it pressed to the ground?
At a certain speed with this design would it make sense for the rear assembly to be a semi-lifting shape the causes the rear wheel to no longer contact the ground and steer entirely via aerodynamics? The goal being to reduce steering instability introduced by ground irregularities.
You could try to angle the rudder/steering axis to bring it closer to the contact patch of the tire?
Yes, and I have a test rear tail for V2 that has caster. The challenge is that the caster angle has to go the other direction for stability, but the angle allows me to mount the servo a lot closer to the wheel.
Could you rotate the steering pivot axis to lessen the mechanical trail? There would be some jacking effect, but I'm curious.
With V2 I'm going to try a few different tail designs and this is one of them. It's hard to package that, but I'm going to try something that may not be aerodynamic but at least will test out the concept.
I feel like a solid front axle on a fwd could introdruce some problems on braking
As a complete layman, I have one suggestion: why not have the tail rudder pivot on the axle line, and the forward part of the pivoting rudder will also end up offsetting the wind forces the servo needs to overcome.
Also, and I assume you have reasons, but why not add a small horizontal stabiliser to the tail?
Dunno if a ground-effect stabilizer is possible. A v-shaped tail that will generate lift if one of the surfaces come into close proximity of the ground to help force the roll back to neutral?
That would be cool. I would definitely need something like a wind tunnel to test that. The rule makers would have never seen that coming as a possibility.
Awesome video and project! Can you use a geared rear steer so you can use more of the rear steer servo travel? Also, I'm sure it's a tradeoff between weight and required acceleration, but in landspeed racing more weight is better, up to a point. Not sure if you have max weight requirements.
Thanks! Early on I played with some designs with two idler gears to connect the servo to the hinge point. The issue I ran into was getting enough of a reduction. I think that could work now, the gear would just stick out both sides of the tail, but it would be easier to cover as the arm is sticking out 25mm in V2.
Also the benefit of the gear drive is that the steering rate is the same in both directions, right now there’s about a 10% difference in steering angle for the same servo movement left to right.
@IndeterminateDesign one more thought - I (think) it's going to be a huge challenge to get the 'rudder' and wheel to work at the same 'rate', especially over the multiple speed ranges. Maybe a wheel below a certain speed and a micro rudder ran by a tiny servo above some speed? I'd love to help in any way I could!
@@IndeterminateDesign Would a chain work to transmit steering angle/ serve as a reduction?
Im currently building a vehicle with a single hub motor at the front and rear steering, a bit like the yellow one you showed in a previous video. I figured the CP would be too far forward in a reverse trike layout but maybe im wrong about that with the nose sticking out so far. Are you on the rossa FB group?
For this car the CP is the furthest forward I’ve ever had, about 160mm ahead of the CofG. I’m not sure how vital it is for stability, in reality you can always adds fin which really doesn’t add very much drag. I did even see that ROSSA had a Facebook group, I’ll look at that for sure.
@@IndeterminateDesign It's mainly filled with people running similar 1/7 scale setups but there's a fair few running custom streamliners. In particular Steve Eng and his Beast car. I'm hoping to attend this next year with a few models we've been designing. Coming from R/C planes, having the CP in front of the CG seems like a recipe for disaster but a fin could definitely fix that.
one thing you didn't mention is that your center of pressure will change as AoA and rudder move, particularly it looks like your model is very stable in yaw, but not in pitch
I have thought about adding horizontal stabilizer to the rear since the rear has almost no downforce. With a long wheel base car like this, will pitch still be an issue? I know for airplanes this would probably be very bad. With the flaps up the CpZ does shift rearward because because the drag on the flaps.
@@IndeterminateDesign combined with the stiff suspension it might lead to porpoising.
The flaps should move the cp towards their deflection, it might lead to sudden takeoff when pivoting to the low drag position
Have you considered this same configuration, only with four wheels in front, each with it's own independent suspension, and all driven?
Yes, I have a few different concepts I designed. I want to try the 3 wheeler because it's the lightest and most aerodynamic. Ultimately I may end up with a 4 wheel differential steering concept.
@IndeterminateDesign 👍👍
Could making the leading and trailing edges of the wheel hubs round help reducing drag?
If you need to move the center of gravity backwards, maybe use beefier steering motor, or motors, maybe even strong enough to move the mechanism into it, maybe using two servos get get the force you need if one servo that's strong enough by itself is too wide?
Could tilting the steering pivot angle help with stability?
I definitely am looking at stronger servos. This one was less than $5, there are some really nice cordless ones with 5x more torque.
I’m going to try a few different tails for V2, and one of them will have some caster angle added. It’s hard to package but I can make a prototype for initial testing.
Curious if a streamliner is the way to go for RC Speed Record attempts because line-of-sight and radio range issues limits the run length. ~150mph in 400sh meters is extremely fast drag car territory (probably talking 8-9second pass), so your accelerations are actually very high and things that work on a streamliner (narrow tires, minimal downforce) don't lead to a car that accelerates well.
Yeah, I was hoping to get more test data from this car to determine the true acceleration rate. I have it modeled with a relatively low coefficient of friction from the tires. The power to weight ratio is what really helps these cars, roughly 1hp/lb.
@@IndeterminateDesign My impression of most of the ROSSA cars (at least the ones that are prominent on youtube, Talbot, et-al) is that they mostly try to brute force the solution, so you can still probably do really well just with the amount of thought/calculation you put into your designs. Just wondering if a more conventional 4-wheel layout but using active-aero and the aero fine-tuning you have done with Airshaper would put you over the current record. The current record 4-cell car looks like a very conventional RC car plan-form with a very vanilla lemans prototype style body
I've been (very) slowly working towards building a car to tackle the Nitro record(s) since they are a relatively measly 120ish mph.
One thought I had that maybe you could expand on:
Use full travel, very soft suspension. But have LVDT/linearpots to measure suspension compression and use that as feedback into the active aero. That would let you maintain minimal downforce to keep the car trim/level and would actually give you feedback on how much downforce you are making since you could use the wheel rates to back-calculate the aero load.
Also tire durability appears to be a major issue on these cars at the higher end.
There are several of us that run but aren’t content creators . But more power adds more weight so more power ect gives diminishing returns. Radio range isn’t an issue but seeing it sure is. Not many people can see these @1500ft+
a little suspicious of the rear "fin" size but looks promising. i dont know why but i enjoy building and designing more than driving, is it the same for you?
Yeah, I think it’s definitely too large but I’m planning on limiting the steering to 0.5deg or less after 30mph. I think it has way too much control authority.
I wonder if extending the tail fin forward of the pivot point might improve the steering at high speeds. Moving the CP forward of the pivot would cause the airflow to help turn the wheel in to the turn when the car starts to go sideways. Maybe moving the pivot point over to the wheel axel would help also.
What would happen if you added down force to rhe rear wheel?
That’s an interesting idea extending the pivot point forward. There’s not a lot of room so I need to plan my with that idea.
I am concerned about the downforce on the rear. Several people have suggested adding a horizontal stabilizer of some kind. I think it may make the car more pitch stable as well. It’s just hard to package of course, but I’m going to make a few different test tails and see what works best with V2.
@@IndeterminateDesignyou could look at a counterbalanced tail surface... Like the rudder on a piper cub. Where the top of the rudder extends past the hinge point.
Maybe some form of front torsion bar could reduce wheel hop during the tire limited phase?
That is an interesting idea. I've been trying to think of ways to allow the motor to move with the axle. I need a subframe inside the chassis basically.
I wonder if torque steer can be a problem without suspension? Like, if only the left wheel catches air, the right wheel will try to steer the car to the left?
Long answer is maybe. I had a hub come loose so only one wheel was powering the car, and it does slowly pull to one side when this happens. Fortunately, the car is so long and the wheel base isn't very wide so the torque moment from that one wheel isn't very strong. Now the rear is a different problem, even when I'm not turning, without any weight back there it wants to steer the car and it has a significant leverage because of how long the tail of the car is.
With a solid axle and the motor shaft the same direction (parallel), there should not be torque steer, unless weight distribution ot aero is not symmetrical.
Think looks like a sting-ray, especially with the steering oscillation...
6 minute's in. I was looking at your three wheeled design.
In my opinion, the car, looking like that, or typical land soeed designs, should want to weathervane.
So, it should want to do that with the designs appearance, however any steering input whatsoever would do the opposite of what a vane would want to do.
My point is, the fin should move in the opposite direction to the rear wheels steering angle to counteract the wheel.
Maybe it shouldn't even move.
That is an interesting idea and would be worth trying out on V2. I really don’t know how much I want that rear wheel to move at high speed. It was way too much control authority. Obviously I could use a gyro to stabilize the car as it would be much more sensitive than a human, but I don’t want to have to go down that road and have another car that can’t be drive ln without electronics.
Not done with the video yet, but I just thought that maybe you would like to have a clutch/disengagement mechanism for the gyro/wheels since my understanding is youd have to spin the gyro with the only motor allowed in the rules, meaning youd be robbed of a lot of acceleration from spinning it from 0 while accelerating the prototype. You would also have the advantage of it being stable from the get go because you would decouple the drive, spin the gyro, then the oposite and launch the thing at full tilt with the gyro freewheeling at gynormous rpm (cheap-o ceramic bearings might do just fine for it to maintain a decent rpm until the end of the run). I know you are in a budget, but consider using clutches or a differential and separate brakes per wheel on the drive as a means to have torque steering & electronic stability control. Aight, back to watching the video.
That’s a cool idea. I think the rules mean an RC gyro. That’s what people often refer to the receivers that include an electric MEMs gyro. It keeps the car driving straight. For me, I’ll be using a small 9 axis IMU.
@@IndeterminateDesignRather than the complexity of a clutch you could use a one way bearing....
if the rod out to the tail were angled, you could have some steering by rotating it. This should have good stability and great mech. advantage; plus it could be very low profile. But the turn radius would be very limited.
I really want to try that. I saw another RC speed run car that has rear tilt steering. Is it just the contact patch being offset from the centerline that causes it to turn?
I’m thinking about limiting the steering based on speed. Maybe at 30mph, the steering range drops to 1/4 degree or so.
@@IndeterminateDesign If there is a kink in the shaft you're turning, you get both a turn and an offset effect -- but both are small.
I'm thinking something like a hex key -- a long side and short side, with an angle between. Wheel/axle on the end of the short side.
Hi Afxentis now has a record of 183mph on 4s
Ah, that changed fast. I kind of thought given my rough math the 180s seemed pretty doable on 4s. I need to find an airport to run at then for sure to even try to break that record.
Have you ever tried to install air brakes
I thought about this, and honestly I think having them on the tail would be key for stability. The flaps I’m using already might cause stability issues.
I think you have your whole design backwards, for stability the delta configuration with front wheel steering is going the be far more stable. ( I know you cover this)
Cars have front wheel steering for stability, forklifts have rear-wheel steering which makes them unstable and more maneuverable (like an f16 is aerodynamically unstable to increase maneuverability)
About the front wheel drive, again I think you've got it backwards. A rocket is more stable when pushed from the back then pulled through the air. the reason you need weight on the rear wheel is stability, if essentially the only thing touching the ground is fat front tires, they want to be in the back, because they cause drag like a fin.
I do really love the rear wheel+rudder assembly, I'm just not convinced it will ever be ever be stable, that is asking so much of the servo. I'd expect it would need a custom PID tune to prevent catastrophic oscillation and over correction at higher speeds
You started by saying 'first principles' and wanting stability, then picked the least stable option, If i were you id move one to an RC nissan deltawing
Really cool shiz and well made video tho
You make some great points. I am honestly up in the air about the whole configuration of the car. I’ve thought a lot about designing a delta configuration car, and there is a land speed car called the Carbiliner which is basically this car in reverse with two inline front wheels.
The challenge I had with the streamliner cars I designed was the instability under braking caused by only having rear brakes. I need a way to package AWD or have separate front brakes. Also the weight distribution can be tricky as well, these cars have so much relative weight in the battery packs.
@@IndeterminateDesign I didnt realize I had come across a few of your vids already. That 3d printed hydraulic setup was so neat! subbed
I'm thinking maybe you could salvage this layout by increasing the size of the rear vertical stabilizer (go look at just how big they are on a b-17 or b-29)
maybe preload steering to prefer to stay straight without servo power, could solve the issue of play
practically, the rear should really have some downforce for stabilities sake, would keep your tire on the ground (i dont think that compliant wheel is much better than having a flexible frame connecting the tire to the front)
down force on the rear wheel could be used to preload the steering to stay straight, like a bicycle
Rear wheel steering proved exceptional for Thrust SSC.
@@joshtaylor6911 I had totally forgotten thrust ssc was the same layout, but it had much weight on the rear wheel, and a much larger vertical stabilizer, it looked pretty much like a dart from the side and top, instead of a backwards dart. The rear wheel steering there is the one exception they made for stability.
at this scale, the tolerances of the linkages, and at top speed the servo control loop are a pretty big problem
Be careful with using the active aero as a brake, may end up “blanking out” the rudder and causing a loss of stability. Same reason a “deep stall” occurs in aircraft.
I hadn’t thought about that. Ideally I would have the brake at the back of the car entirely. I’m still not fully sold on this approach with the rudder. I think at lot can go wrong if I don’t limit the steering to a very small amount.
@@IndeterminateDesign Yeah, the only way to know is test, one good test is worth 1,000 "expert" opinions!
RC cars have suspension too !?
Yes, many of the speed run cars don’t run a suspension all or one that is so stiff they are basically solid. These cars can be very pitch sensitive and fly into the air otherwise. I think this car wouldn’t do that as bad just because of the shape.
huh, neat.
Why design when you can steal? The back of your car or "tail", is acting exactly like the back of a "tail-dragger" airplane. Look at all the old planes that dragged their tails in the dirt, grass, etc. How did they solve the problems you are having? You could actually put a "skid" on the rear and some small cannards. As soon as the car moves forward, the rear comes up off the ground. No dragging, no suspension. You could even make the skid/tire "fall away" as the rear lifted.
That’s a good idea. There’s no rule saying all the tires have to stay on the ground. 🤔
the difference is that airplanes don't torque on their fron wheels. Is aero strong enough to keep the tail floating? otherwise you'll have to control the acceleration like a Segway
@@gunar.kroegerArduPilot runs on an ESP 32 these days. Just use the wheels to accelerate, with active aerodynamics for steering and downforce control.
It's better to think of it as a wing in ground effect vehicle.
They didn't solve them, kinda. Its just a lighter system for an airplane.
Thats the downside.
Look just use 3 or 4 wheels, have the rear non steering and steer with torque instead at the front?
I doubt ardupilot could solve it. on a plane all forces are in line with the fuselage so keeping the tail horizontal requires minimal force. on a car you have a lot of torque from the wheels. on rear powered vehicles it causes the whole car to wheely when accelerating. On front powered vehicles the rear is pushed into the ground. some tiny winglets will not be able to counterackt if you are trying to go fast
The big issue the ROSSA land speed boys have been facing are the tyres. Not so much with the areo.
Yeah, I have some special tires that I know will handle 30k+ rpm. Finding a place to get to that speed is hard to find still though.
@@IndeterminateDesign save some pennies mate, and get over to ROSSA.
great informative and entertaining video! Have you ever considered using flexible aero elements that can be found in F1 front wing?
What I've read about the flexible elements is that if it wasn't for the rules, F1 wouldn't use them. They're very hard to tune their stiffness, and they can oscillate which ruins downforce. I thought about using a spring and damper on the flaps but this weighed more than the servo.
I have seen some really cool wings where the whole airfoil can reshape itself via some cables being pulled. This could potentially create more downforce at low speeds and less drag at higher speeds. Part of me wants to try this, but for once I want to try and keep this simple.
@@IndeterminateDesign Flaps already look insanely good! Which ever you decides to do, I'm excited to watch the next part of this project.
Bro you need tail part like shadil cork
I am not a fan of the rear steer. One way to help the sloop is like 3d rc planes do, they use two cables, one on each side in a pull/pull mode. But at 100+, any sloop is magnified.
You should have a large fixed fin on the rear and the wheel steer inside (yes I know thats more drag, but its more stable), if you want a rudder, it should be small, not the whole thing moving, just way too much imo. Good luck
I agree. I’m concerned the tail has way too much control authority. I’m going to try a few different tail designs for V2, one of them I’d like is a fixed tail like you mentioned. I need to get higher speed tests to see how much steering I actually need.
@IndeterminateDesign good luck.
Another thing I am seeing an issue with is traction. The full size cars that use narrow tires are thrust propelled, these wheel propelled the tires are much wider
@@IndeterminateDesign one thing I laugh at the rossa cars is the drag, they pay zero attention to the rear of the car using pan car bodies designed for road racing at ~50mph max (I was 2nd place at the 1999 worlds).
I prefer rear wheel drive as the weight transfers back to significantly help straight line traction.
Not that you want to open this can of worms, a traction control reading front and rear wheel speed.
Are u in the uk?
Sadly no. I was planning on traveling there if this car concept proves itself out.
looks like a scorpion
Run it on a straight tether line ..
I love those tether line cars. That’s what inspired my streamliner designs.
"ground effect'... Utilize afan...turbine...to suck down the vehicle.... Mind the rotational forces ennacted on the moving vehicle... There'll be tendencies to pull the vehicle to 1 side. Possible solution is to have two opposed rotating element's... Now you are talking down force and drag... Get rid of that! "air foils"? Ditch them... When you have that ducted turbine/fan/ or fans...with a skirt surround the edge...think that weird plastic at ice rinks...low friction...and a simple mechanism literally using a lever.. Maybe a spring...better, 3d print a price where using material's width and different mass in specific sections to provide that spring force but no other parts are required to be added...what is the word for such parts? Designs? Compliant parts? So, when the vehicle starts to lift... Pressure is removed causing the mechanism to lower that bottom skirt...and raising it as the car squats.
Trust me...ditch the wings and 'traditional' aero ideologies.... You'll have incredible results with a turbine...just don't forget that rotational force which will pull it to 1side.
My previous video was about a fan car, and I'm working on some concepts for another fan. The challenge with the fan car is weight and they tend don't work well at higher speeds. More air is forced under the skirt so it become less efficient.
You've wasted way to much time on 3d printed bodies. 3d printings is way to heavy and brittle. Great for prototypes not great for production or finished models... better off using the print as a shell for vacuform poly carbon shell. Good luck I would love to be proven wrong.
With all due respect and from my ignorance, allow me to suggest a wheel that cushions this ruclips.net/video/J0sS3Z3BkJU/видео.html And because there are three wheels, I suggest you watch this video of German record-hunting cars. I love the minute autounion 3:00 ruclips.net/video/_I_8VsH01rk/видео.html and es.wikipedia.org/wiki/Autom%C3%B3viles_de_carreras_Auto_Union#/media/Archivo:Auto-Union_Typ_C_Stromlinie_front-right_Audi_Forum_Ingolstadt.jpg