Testing WWII Era Terrain Following 'Radar' On R/C Plane
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- Опубликовано: 30 янв 2024
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I'm not surprised you couldn't feel much ground effect with this glider, the Fox is more of a glider shaped sports plane than a real floater. No 1200g 2.3 meter plane is going to be much of a glider, my X-Dream 2m is 474g RTF and that can float on ground effect for the length of our runway - you need spoilers to land it
What if you add a shock from an rc car as a dampener on the rods.
Ideally I would thing you would want the rods touching the ground constantly. Maybe add a really weak spring in line so that the rods would be more progressive in the authority adjustments.
Maybe have a gear reduction on the arms so you can still have large surfaces but less aggressive inputs.
A problem could be the sonar bouncing unevenly off the water surface and it’s getting a little bit of mixed feedback from the mix I’ve heard it happens when water is choppy so idk just my thoughts love your videos and can’t wait for more projects
Does your radar buffer the altitude before it outputs the control? I would think (if I understand what you are doing now) if you just slowed the response of the output, the software would be catching peaks and troughs of the waves, and the delay between what is sees, and what it outputs, would be problematic. So some outputs would be greater than others, and some would be negative vs positive. I.E. You are compensating for problems you already passed.
I would assume this action would lead to porpoiseing. If you forward angle the sensor a bit, and did some math to compensate for distance and time of the radar, you could avg the wave height, before the aircraft is over it. In this sense, the aircraft would fly as if it was over a level surface. It would be looking at waves ahead of it, thinking it over, and acting at the appropriate time. Then you could leave the sensitivity up, but create a digital travel limit of the servo outputs, and set a fail safe climb altitude if those limits are exceeded. If you really wanted to get fancy, you could do the fwd looking sensor, and a direct down sensor, then have your software crosscheck the data of what is trying to accomplish, vs the actual result. An algorithm of altitude results from the intended vs actual altitude could also be running to fine tune on the fly.
The only problem being the occasional freak taller wave, but I lack the understanding of how a wave peak would physically disturb ground effect, or if the plane would mechanically avg that out.
I had this Idea after your last video, What if you where to mount Rotating Magnus effect wings with the added benefit that they might bounce out of the water like the Dambuster Bombs. wuld love to see you try this.
We all agree that you should continue the Solar Plane series!
YES
yee
Yes
yup
Yes fly it from one side of America to the other (within reason).
Those droneless camera birdview shots of the foam plane were top tier lmao
As usual, fantastic film. Re your vortex shedding imagery, I used to be a scientific photographer at the UK’s MoD Royal Aerospace Establishment, not really what you were trying to do, but in wind tunnels we used to use UV mini tufts on models to view localised flow patterns on the surface of the fuselage. Short lengths of thin string, with a UV fluorescent dye on it, at night with a good UV source and a camera with a high frame rate might give you some lovely images.
Keep up the great stuff.
That's a great idea.
Farnborough?
@@FaustoTheBoozehound
Correct.
@@FaustoTheBoozehoundRAE establishment, UK. We're in the presence of aerodynamic royalty!
Thanks for your input @1967AJB! These Americans have trouble with places outside their country...
It seems like the feedback loop needs to account for both height above the ground and pitch. A pitched down plane nearing the water needs to pull up, but a pitched up plane near the water will soon be high enough above the water without further pulling up. In other words, the altitude adjustment loop needs to know if it is too low and pitched to go lower, or too low and pitched to go higher, with a weaker or even inverse adjustment in the latter case. Likewise for being too high. This was very apparent with the stick based design, but I suspect would be much easier to implement with the flight controller and ultrasonic sensor design.
That's a good point. Maybe a plane that's designed for canards (like a Long EZ) would be better, as it would have a longer nose.
Similar to my theoretical solution, which was to have the servos controlled directly by the radar output’s RATE (i.e. how FAST the plane is climbing or falling) that way as soon as the plane starts to level out, the servos will be at zero. You could have the plane SLOWLY approach the ideal cruise height, then engage the subroutine that controls the servos. I obviously agree this would be much easier with flight controller than with “mechanical radar stick”.
Nice. Could be done with a forward and rear wand. I also think a damper on the wand/canard system could help.
@@ZenZooZoo That's already what's happening with the D part of the PDI controller, no?
@@snower13 that's a clever solution, would be interested to see if this sort of mechanical method could work
You should measure the lag of the sonar sensor. Any lag in the PID "plant" moves the zeros and poles of the transfer function, which affects oscillations and stability
The lag in the sonar sensor (miliseconds) will be far less than the response time of the aircraft (seconds)
@@calloutman Yeah, control loops with significant delay can be a right pain to get fast response out of. It might be an idea to move to a predictor type controller (e.g. Kalman filter) rather than a PID type. However, first job is probably trying to figure out what the transfer function of the actuator->control surface->attitude/altitude->sensor combination is. I wouldn't even like to even hazard a guess what order of response it has.
Wingtip vortices are fascinating things. At Oshkosh one year they had a Sea Fury with wingtip smoke being followed by a Mustang down show center. At the end of the runway the Sea Fury would pull up hard and bank to the right...which turned the smoke to a swirling mess behind it that in a couple seconds all came together in a perfectly round smoke ring...that the Mustang would then fly through. I thought this was the neatest thing I'd ever seen.
was that... safe?
@@NoNameAtAll2 Sure...why not? The air in the center of the smoke ring was obviously still and at speed with the high wing loading of the Mustang it blew through it with barely a bump. If it had been causing any issues I really doubt they'd have done it again and again for their entire demo time...but they did.
Great series!
In my experiences with PID controllers, sometimes using x*abs(x) on the output can smooth out oscillations. In other words, square the output of the PID, but keep negative values as negatives. This results in exponentially lower sensitivity the closer you get to zero.
Flight ontrol systems engineer here. Your videos are a delight, but with a bit of frustration around control design. I am sure that if you invested half as much time in beefing up your control systems engineering skills as you spend with 3d printing and whatnot, you'd be much less often puzzling over what's happening and you'd cut on the trial-and-error stage.
The hard part is probably the aerodynamics though. Unless you make a wind tunnel, or you invest in CFD software, you'd have to characterize the plant's response in-situ, which is challenging (but since you seem to be able to always have something that at least flies, it might be sufficient).
Anyway, hats off to your dedication.
Mechatronics engineer here!
I'd love to see this project developed further. Im lead to believe that the oscillation problem may also be a result of the senor range. If the controller always has an accurate height measurement using a range of sensors (like IR and sonar fused with some form of Bayes filter), then the PID gains can be dynamically allocated. An airspeed measurement would also be useful to scale the gains, as the controll authority dramatically increases with airspeed.
I like this approach because you don't need a perfect plant model, but you do need a half decent starting guess. A motion model is easy enough to find insitu for the bayes filter, though changing wind speeds/ direction might make for a new headache.
So with just height and airspeed measurements, the controller should have enough information to fly without oscillation at any altitude. Pitch sensors may not be needed as sinkrate is arguably more important for stable flight at ANY airspeed. The only other useful information would be the terrain height AHEAD of the aircraft, similar to the terrain warning in real aircraft. this could just be a simple IR senor with a 5-10m range in this case.
I think I still have the code to do this from a similar robotics assignment from Uni. Id be happy to dig it out for anyone interested.
Loving the ground effect series! I look forwards to your next idea!
FluidX3d is an alright free for non commercial CFD program. Kind of a pain to use but it runs alright on consumer grade hardware if you have a decent discrete gpu.
EE with an emphasis on control theory and comms, its kind of difficult to just learn about control theory as there aren't many online resources. You'd need to take classes or buy some college level books and teach yourself, which isn't easy. I think if he really dumbed down the response rate he would have gotten better results.
@@Lost_Hwasal Either go through the hassle of teaching yourself, or better yet hire a graduate engineer to help with projects and teach you these kind of finicky concepts
OMG that vape car hotboxed scene was hilarious! Actually made me laugh so hard. Thanks for that.
Pull up to the vape store and tell them that my vape pipe has gone on thermal runaway.
Watched the whole ad just because of that part
JJKHNJJHNJJ?
I'm flyin low checkin efficiency gains
Testin wing shapes on RC planes
Deep cords feel stronger ground effect buzz
But thin ones might get better results
This Fox glider got a long wingspan
Should feel ground effect above a meter scan
Installed sensors, art pilot too
Try fly itself at the right altitude
Tried followin the surface below
But it kept bouncin, just wouldn't flow
Tuned the PID but nothin worked right
Still oscillatin out of sight
Pontoons I added for water tests
Flyin on the lake, flyin my best
But the controller still had issues
Keepin it steady, raisin fizzles
Tried flaps next to make it rise higher
Near the water, make the altitude wire
But they couldn't stop the jumps
The pitch and airspeed just too much pumps
Wand concept next, canards it did flex
Rotatin surfaces based on checks
But responses had to be lessened
Then it was too weak, flow now questionin
Came up short on solutions galore
But problems like these I want more
Control systems is beyond me ya'll
Hit me up if you can help it's not small
Learned thick cords feel it most true
But efficiency gain scales are tough to accrue
Scale affects it heavy too it's clear
Big planes don't feel it, only up close and near
So ground effect tests will keep rollin on
Till self stabilizin designs are fully gone
Appreciate y'all watchin my vids
Subscribe if you dig it, peace I bid
🔥🔥🔥
I wonder 🤔 how this would sound with a sick beat and Eminem performing 😎❤
The Rate in witch you pump out such high quality Videos is just insane!
That’s true.
which*
witches turn people into a newt :)
@@NoNameAtAll2 ops thanks for the correction.
Great video! As a control engineer, I suggest using MATLAB or similar tools to collect, analyze data and understand how the aircraft behaves. Testing altitude control ideas in the software before trying them out at the lake can help optimize the system. Also, be mindful of potential delay or lag from the sonar system, as ignoring them might cause issues with altitude control. Excited to see your progress!
The polite abruptness of "thanks for watching, bye" - is art. Only reason I'm not mad when these videos end.
The text: My current project is building a plane which autonomously flies slowly and roughly low so I can run a waypoint mission and ride along with it on my bike, watching that footage of you flying your plane next to that boat got me hooked even more now. I got inspiration for this when watching your STOL multi-element wing plane flying a mission in that park. So yeah, shots of you chasing your builds are the coolest!
12:12: Shots like these are what makes your Videos special
On hydrofoil sailboats, the wand connects to the foil via two bell cranks and a push rod. The forward bell crank has a screw to adjust the ratio of angle change to pushrod movement (aka the gearing). In heavier seas we up the sensitivity and in flatter water we keep it as low as possible (because any flap movement is increased drag). It would be neat to see a mechanical tuning system for the canard’s instead of just changing their area. Keep up the good work!
The fog machine in the car. I had a Cheech and Chong flashback moment!
The large tall T wing on the purpose built ground effect plane stabilizes it by being further away from the ground effect itself, and losing more lift as the plane climbs, which makes it pitch down slightly. Maybe the same effect would work with a negative stagger tandem wing, or with small fixed canards near the ground.
Wow flying from your boat looked so much fun with that floater :D
Real neat wingtip vortex visualization! I live under the flight path for 12R at KMSP within a mile of the runway. We can often hear airliner vortices interacting with trees on the ground sometimes after a minute or more after the plane has passed. It's really damn cool to hear!
Something to look at is the airspeed at which the highest efficiency occurs.
A simple starting point is stall speed, as this is easily observable. (other measurements will require data collection)
Typically ground effect helps lower stall speed, and lowering the speed across the performance curve. Effect feels like flying a lighter aircraft, makes if feel more floaty.
@rctestflight
I've worked a bit with terrain following systems, and it might help you to aim your transducer more forward instead of straight down.
That's generally the biggest flaw that most folks encounter with adverse pitch cycling is that the transducer is looking straight down, which causes the angle to point backwards when the aircraft is in a dive, and causes it to look forwards when it's climbing, and this creates a cyclic failure.
However, if you mount the transducer pointing more forward as the aircraft climbs the transducer will not get the necessary feedback, and so it will slowly come back down in pitch which is much more controllable and creates a more expected less chaotic pitch control.
The most practical bit of advice!
While flying an IS-28B2 Lark sailplane (17 m / 55 feet 9 inch wingspan) on landing approach I was instructed to land long as the gliding operation was moving to the other end of the runway due to the wind direction changing. Fully retracting the air brakes while holding an altitude of about 10 feet and at a speed of 50 miles per hour the glider floated the length of the 2300 foot runway with very gradual speed loss, touching down at about 40 mph with an easy roll out to stop at the end of the runway. That, for me, was a very practical demonstration of ground effect. Thank you for all the analysis of the remarkable phenomenon of ground effect.
As someone who formerly worked in a vape shop in the day of the classic mods. I definitely screwed several together and shoved up to 7 batteries in one stlet of copper tubes before it ignored several batteries and I had to throw it out of the garage door at the shop. It would probably create 1/2 the smoke of your machine only using 4 4680 batteries and a massive 8 coil atomizer with less than .1ohm guitar string colis. It was not in any way vapeble and required an air hose and a cut up 2 liter bottle to funnel air and a bottle of vg to prevent it from overheating immediately and going into flames. I installed the security cameras and my boss was there most of the time so he should have stopped us.
This is the most visually pleasing video you or any rc video…er er er has ever made 👍 following your plane with the boat and reaching out and giving the wing a 👊 was tool cool.
It would be very interesting to see more videos following an rc boat plane as it traverses through you experiments and local terrain.
Keep the videos coming 👍👍👍
I haven't felt motion sickness from a video till now. Congrats
I see one reason for the osillation in the linear actuation of the canards, the controller reaction should be weaker at low and stronger at high altitude. If you want to use a mecanical ground following controller, a possible solution would be to use a crankdisk and connect the controll surface at "top dead center" when the "ground following stick" is at its lowest point, with a second lever at the controllsurface right at 90°. But it would recuire some testing.
You are a goldden god. Being able to fly from a speeding boat in rough water, and all the ground sensor elevator control, golden.
Always love your engineering mate! Out of all the RC channels, you use the same principles they use to create real aircrafts.
As always, very fascinating concepts and solutions to your hypotheses! Love your videos Daniel...they always inspire me and provoke much thought!
I love these technical videos of yours. I cannot tell you how refreshing it is to have a real long form video to watch rather than some clickbait BS.
Dude! Another awesome video! A++ all the way around. Content, editing, narrative. You’re nailing bro!
Thanks for inspiring my inner engineer to play. RC, micro controllers, 3D design & printing. PID. Checking all my favorite boxes. Love it! 👍
I love how you add an autopilot to anything that moves. Very skilled.
I think you should connect the giro to the sonar sensor, so you will be able to compensate for the angle change, and almost fully control the plane based on the giro, but adjust the altitude based on filtered and processed sonar data
Wow what a great channel, so pleased I've found it. Can't wait to see what the next couple of years brings!
Love your videos. They are always educational and fun. Keep up the good work.
Daniels channel is the most interesting RUclips channel there is. I even watch his ads. LOL! Seriously, this channel always is interesting. Even when he was a kid.
I'm so impressed with the quality of your videos, thank you for making such interesting stuff without getting stuck in gimmick territory.
You make just such high quality content and explain everything perfectly
Thanks for sharing! Cool what you do! To learn about those wingtip vórtices and the efficiency of ground effect!
This is so interesting! Thanks for sharing your experiments with us.
Fascinating! And i certainly admire your determination!!
Very interesting, love watching the videos, it’s fun hearing the results from your experiments.
the air to air thrown camera shots were great man
I'm a mechatronic engineer (control systems are part of that). A physical control loop, a digital one and an analog electronic circuit all follow the same rules and are modeled in the same way.
In digital you have P, I and D. P reacts directly to the error, I reacts to the cumulative error over time and D reacts to the rate of change of the error.
In a simple physical control loop you have a spring (which provides a proportional response to the error), a mass (which has inertia and doesn't want to change speeds), and a damper (which reacts to the rate of change).
Your physical control loop has only a proportional response to the error, so it oscillates like any proportional-only control loop. If you want to add I and D to get a working control loop, you should isolate the probe from the control system with a rubber band, have a gear system so that a flywheel spins up in either direction as the error changes (to provide I) and a brake that rubs on the flywheel (to provide D). To providing tuning of I, you'll need a way to change the rotational moment of inertia of the flywheel, by either changing the mass or moving the mass closer to or further from the centre. To provide tuning of D, you'll just need a spring or rubber band that can have the tension increased to push harder on the flywheel. Probably the easiest way to achieve this would be by screwing weights into an electric scooter brake disc (about 75mm diameter) and mounting the disc to a drill's planetary gearbox (backlash in a 3D printed geartrain will not be kind to you).
If you want to learn more about this, look into "spring mass damper" systems and state space modelling.
Oh my dear, i love your experiments, thoughts and your efforts. You should be a teacher, but not in school (is boring) but in a free class for all those children (and adults) who are willing to learn for their life and have fun! Thank you so much for sharing!! 🥰😘
Cool progress in the ground effect experiments. Those fog shots of tip vortices is really cool.
As always I leave your videos feeling more motivated to finish my projects and try new ideas. Super interesting video.
One of the best videos so far. Great explanations, education, great footage, and you used so much cool tech: 3D scanner, power bank, lasers, smoke machines, and much more. Very cool. Also hilarious when colin was driving around in a hot boxed car lmao
The ground effect on the lower aspect ratio ("deep chord") vehicle is more noticeable because it starts from a lower point in the efficiency scale, the glider is far more efficient with its high aspect ratio wings, so it seems less noticeable but is definitely there, glider pilots need to pay atention to it when landing. For the "terrain folowing canards" to work I would recomend using a thincker symmetrical airfoil (maybe an NACA 0018) and to limit its actuation to a incidence smaller then the stall angle, what is probably killing the idea is the stall od the surface and non linear response on the canards. For the flaps, it is true that lowering then increases lift, but it also increases pitching momment, so it would be necessary to compensate for that. If you want I'll be glad to help, I belive you come very close to getting it to work
I love this channel. Always something interesting and I love seeing the scientific process in action. 👌🏼
Such good filming.
Good science, too.
Thanks for sharing!
My knowledge of the ground effect is that it's the wind that's normally kicked off of the wing reflecting back off of the ground then interacting with the wing underside and the flow of air, forming a standing wave. A high sweep flying wing should be able to catch some of that air bouncing back on the tips, and the stability can be modified with dihedral and wing twist nicely.
You packed some incredible shots into this video! 💚
The plane with a crutch!
What a mad idea!
I love this mans videos
Magnificently thought provoking yet again. Cool man.
Thank you for this informative technical video.
Really liked this video. Nicely done!
Very good testing process!
FMS are making some gorgeous aircraft lately. I've got the Moa 1500mm. Love it to bits!
What I have just seen has convinced me that the author of this channel is an unbridled GENIUS.
The moment u started to throw the camera I scrolled down and tried to sub, yet I've been a sub for ages and u deserve more dude. Creatively your content is unique.
Honestly lad keep up the good work, ya made us proud son.
Those toss shots are freaking dope
Never cease to amaze me on how cleaver you are
Well done and very enjoyable
This is very cool, don't give up! It reminds me of hydrofoiling sailboats like the Moth that use a "wand" going down to the water to control flaps on the front wing
9:00 That's not a vape, it's a Füm held next to something else LOL
Thank you, nice demo! 👍💪✌
Such a picturesque scene with the plane on the water in the fog!
Definitely more difficult in smaller scale. Nice work.
The shot of the plane next to the boat with the seagull in the background is cool.
Perpetual summer at rctestflight!
My favorite YT channel.
Mechatronics engineer here! Click read more for some slightly nerdy control advice!
I'd love to see this project developed further. Im lead to believe that the oscillation problem may also be a result of the senor range. If the controller always has an accurate height measurement using a range of sensors (like IR and sonar fused with some form of Bayes filter), then the PID gains can be dynamically allocated. An airspeed measurement would also be useful to scale the gains, as the controll authority dramatically increases with airspeed.
I like this approach because you don't need a perfect plant model, but you do need a half decent starting guess. A motion model is easy enough to find insitu for the bayes filter, though changing wind speeds/ direction might make for a new headache.
So with just height and airspeed measurements, the controller should have enough information to fly without oscillation at any altitude. Pitch sensors may not be needed as sinkrate is arguably more important for stable flight at ANY airspeed. The only other useful information would be the terrain height AHEAD of the aircraft, similar to the terrain warning in real aircraft. this could just be a simple IR senor with a 5-10m range in this case.
I think I still have the code to do this from a similar robotics assignment from Uni. Id be happy to dig it out for anyone interested.
Loving the ground effect series! I look forwards to your next idea!
Thanks for listening to my TEDtalk :)
Awesome video. I love your inquisitiveness and quest for answers. I wondered if the wands that stick down might be touching too far back. But what do I know...not a whole lot.
I LOVE your videos!! Keep them coming!
A Close Coupled Canard may be better for ground effect. IGE pressure under the wing increases which causes an upwash at the leading edge which will increase the lift of the close coupled canard, causing a pitch up away from the "ground".
Also a swept wing pitches down less IGE than a straight wing because of less center of pressure shift.
In fact 25⁰ to 45⁰ swept wings with a tall OGE T tail will also work!
That was super cool.
Cheers
That analogue altitude control worked so well!
Awesome video footage really good job
Use forward sweep to get better ground effect by thinner wing chord, this will also Improve the turning ability with less roll. Forward sweep has a similar flow characteristic as ground effect, therefore it will improve speed , lift and weight
honestly I love the “seaglider” concept itself!!
I thoroughly enjoy your sense of humor!
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I think the camera shots in this video proved that aviation is so beautiful whether it be RC or full scale
Nice! Also, your initial plane mod (before the prop offset) made it look incredibly photogenic, no wonder the seagulls were envious
I really enjoy your videos, they are very interesting and informative. Also, the sponsored links and review came in very handy, as I am in the market for a battery backup system for power outages. I will definitely be using your discount code. Thanks!
I would LOVE to see a build video. I love the behind the scenes-how it works- type videos. Yours would rock. If it's not too much trouble.
Nice camera work!
Great video. Love the content. I watch all your videos.
Brilliant video, you're so clever and inventive. I'm building a full scale wing in ground effect flying boat. Hoping to experience the effect first hand and learn more about it.
YES! I've suggested this in your comments before! NOICE!
fantastic as always.
dynamic soaring when! 😡
great work man, always love to see your projects
great vid man, i had one of these they are great
As you said at the end scale seems to be the biggest success factor. Go big.
Wonderful!
I could watch your videos every day from now on…
Amazing footage 👍
12:13 Sick jump
One thing you could try is making the rods of more flexible material. Even more so you could have them of greatest flexibility at the point and gradually decrease flexibility down the length if the rod. This could be done in part by varying the width of a given material
This is fascinating, I believe that the efficiency gains of ground effect can influence the stability quite a bit which could be the cause of the oscillation, just my two pence.