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X8R is the most universal, if you intend to move the receiver between drones with varying FCs. Does the X series also have telemetry?
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Sep 8, 2015 17:15
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All the X series that I posted should have telemetry, dunno if this is true of the series in general. I only have one drone now but also one fixed-wing. The DJI drone has the Naza-M thingie that supports S-Bus for input. However the plane just has loose servo and SC connections so I'll need a 4-channel receiver there unfortunately. So the D4R should work with the plane, but it supports RSSI and CPPM while the Naza specs (http://www.dji.com/product/naza-m/spec) only mention S-bus, which as far as I can tell is a different thing. So... I think I'll just get the X8R now and move it as necessary between the models.
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Sep 8, 2015 21:56
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I would use the D4R for anything that can accept PPMSUM input like a flight controller for a multirotor. Use the larger controllers for things that need individual servo outputs.
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Sep 8, 2015 22:13
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My mobius died a few months back so I just took a chance and ordered this http://foxeer.com/HD-Sport-Camera-1080P-60fps-Ambarella--g-9.html It looks like it could be a good upgrade over the mobius in a similar form factor. Hopefully it isn't garbage 
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Sep 9, 2015 00:26
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Ah, I'm nearly done with my custom design. Given that I still have to wait two weeks for the guy responsible for the water jet cutter to return from vacation, I'm frantically checking the sketches. When I'm done, I probably need to build a RC boat or some poo poo to pass my time. Weather's only getting shittier. Image dump: Inventor screencap: http://i.imgur.com/VKEIqo0.jpg Quick render: http://i.imgur.com/dSrJ7cS.png The custom plates: http://i.imgur.com/GuiJV2E.jpg http://i.imgur.com/b9ETwdr.jpg http://i.imgur.com/eNTGswG.jpg The camera chassis/enclosure. loving pain in the rear end to design complexer parts in Inventor, especially for the shell tool not to throw a poo poo fit (don't want a solid ABS block on the frame), probably still less drama than some 3D modeller: http://i.imgur.com/uvtzF9H.jpg http://i.imgur.com/J4A9vHB.jpg Why there's serrated edges on two plates  :http://i.imgur.com/oijwDW9.jpg
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Sep 9, 2015 03:02
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I like the  approach, but I would have guessed that props (and all the air they are moving) are a strong enough factor that you couldn't discount them when profiling the airflow around the frame. Am I way off?
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Sep 9, 2015 03:27
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Yeah as I understand the props create a significant mess around them, but maybe he knows something I don't, which is actually pretty likely. Looks like a cute bumblebee  helno posted:I would use the D4R for anything that can accept PPMSUM input like a flight controller for a multirotor. Yeah ok so that Naza-M spec page doesn't list PPM support, but the overview and PDF manual mention it as possible inputs. Great, right? Except this receiver won't work with my new Taranis because the EU firmware doesn't support the D8 mode. http://www.frsky-rc.com/BBS/viewtopic.php?f=2&t=6986 So I'd need to reflash it with non-EU firmware, and then subsequently have to reflash all EU15 receivers or get hosed. What a mess. Anyway, it seems that none of the places that claim to have it actually have it in stock, so I'll get a singe X8R for now.
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Sep 9, 2015 09:11
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mobby_6kl posted:Yeah as I understand the props create a significant mess around them, but maybe he knows something I don't, which is actually pretty likely.  Even if the "optimizations" won't do anything, the changes are worth it alone because the serrated edges give the drone some character. The initial straight edges looked dull. Verified by importing the whole shebang into Unity and checking it out with my Oculus Rift. 
Combat Pretzel fucked around with this message at 11:07 on Sep 9, 2015 |
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Sep 9, 2015 10:41
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Combat Pretzel posted:Actually I don't. I just assumed that at very high flight speeds, the airflow overwhelms the prop vortices (--edit: at least the turbulences created near the frame). Whether that's the case, I don't know. Some CFD guys on another forum say that the app probably doesn't resolve it well enough and it won't do poo poo. If it didn't require me to build some huge box with stator vanes, I could create a makeshift windtunnel out of a box fan. The airflow from the props will be faster than the airflow over the frame, so I think they're kinda essential.
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Sep 9, 2015 19:48
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Props have big effects even a good distance away from themselves. They matter, quite a bit. ... I fully encourage building a wind tunnel. I've done that...
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Sep 9, 2015 20:26
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I crashed my thingy and now it sort of drifts to one side, I think I banged up a motor. It's not consistent though and sometimes it doesn't give me any problems, so I might have cracked something internally and it's introducing vibrations to the FC board. I took the opportunity to add an anti-vibration plate, now the Naze is isolated from the PDB and frame. Test fit:  Ended up having to make little feet to raise the FC up, but everything fits together:  
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Sep 9, 2015 20:48
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Is that thing completely 3D-printed? It looks pretty good for having been in a crash.
mobby_6kl fucked around with this message at 21:24 on Sep 9, 2015 |
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Sep 9, 2015 21:22
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If my primary goal is to record my FPV flights and eventually use it with a gimbal for basic aerial videos, is there any benefit to getting a GoPro instead of the much-cheaper Xiaomi Yi or similar? I've never even used a GoPro in person so I'm not sure what I'd miss out on.
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Sep 9, 2015 21:36
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Krittick posted:If my primary goal is to record my FPV flights and eventually use it with a gimbal for basic aerial videos, is there any benefit to getting a GoPro instead of the much-cheaper Xiaomi Yi or similar? I've never even used a GoPro in person so I'm not sure what I'd miss out on. The video from a gopro is marginally better in certain areas. It's not a huge difference. There are plenty of reviews online comparing them with example pics and vids.
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Sep 9, 2015 21:39
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I'm no aerodynamics expert but I would think that the power to weight ratio of race quads is so high that frame aerodynamics probably won't have that much effect. Given that efficiency doesn't really play into races much a less aerodynamic design is just going to use a bit more throttle to make up the difference.
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Sep 10, 2015 00:52
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Combat Pretzel posted:Actually I don't. I just assumed that at very high flight speeds, the airflow overwhelms the prop vortices (--edit: at least the turbulences created near the frame). Whether that's the case, I don't know. Some CFD guys on another forum say that the app probably doesn't resolve it well enough and it won't do poo poo. If it didn't require me to build some huge box with stator vanes, I could create a makeshift windtunnel out of a box fan. I saw a thing on mythbusters where they just bought a whole bunch of drinking straws, left them in their boxes, glued all the boxes together, and stuck them in a frame:  It was like this except for bigger - larger than a box fan if I'm not mistaken.
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Sep 10, 2015 02:21
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DreadLlama posted:I saw a thing on mythbusters where they just bought a whole bunch of drinking straws, left them in their boxes, glued all the boxes together, and stuck them in a frame:  I'm so onto it! --edit: Trying to get some hollow and light ABS airplane to fly on an electric turbine is a foolish endeavour, isn't it? Combat Pretzel fucked around with this message at 03:08 on Sep 10, 2015 |
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Sep 10, 2015 02:26
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mashed_penguin posted:I'm no aerodynamics expert but I would think that the power to weight ratio of race quads is so high that frame aerodynamics probably won't have that much effect. Given that efficiency doesn't really play into races much a less aerodynamic design is just going to use a bit more throttle to make up the difference. This guy said a whole bunch of words about it in his latest build http://www.shendrones.com/krieger
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Sep 10, 2015 04:19
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mashed_penguin posted:I'm no aerodynamics expert but I would think that the power to weight ratio of race quads is so high that frame aerodynamics probably won't have that much effect. Given that efficiency doesn't really play into races much a less aerodynamic design is just going to use a bit more throttle to make up the difference. So here's a few things about drag: 1. Drag goes up to the square of speed. 2. Drag scales linearly with frontal area. 3. Drag is also affected by surface area, but the interaction of wetted area and drag is very complex. Generally speaking "less is better". https://www.grc.nasa.gov/www/K-12/airplane/shaped.html Almost all quadcopter drag is flat plate-ish drag. This is AWFUL. Anything between your prop and the space behind it is like losing prop area. Having well streamlined arms under the props would cut the drag from the arms by something like fourty times, and that assumes the frontal area is the same. So a short sidebar about streamlining, and propwash. The airflow under the props is going to be going at a wide range of directions, which means an ideal airfoil isn't .. ideal? Or even possible. If the arms stall out, you'll get sudden increases in drag, which is a bad thing and could lead to very interesting airframe behavior. Behaviors not unlike a motor stalling or an airplane snap roll. So you'd need to chose a less ideal airfoil, one with less than a 3:1 fineness ratio... So the Cd will be more like .15 instead of .045... Still we're talking a 10x improvement over flat plates. The fuselage of a quad is also a problem. The open sides present more area to the airstream, and while they're in turbulant air coming off of the plate in front of them, or the crazy airflow coming off the props, you're still looking at additive effects. I strongly suspect a flat plate design, and a phantom, of the same size and powerplant would see large differences in flight time. Even more if speed is involved. A Yolo Wizard posted:This guy said a whole bunch of words about it in his latest build http://www.shendrones.com/krieger He's totally going the right direction.
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Sep 10, 2015 04:59
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Combat Pretzel posted:
I know from playing KSP that if one electric turbine does not work, you probably need six.
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Sep 10, 2015 05:07
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Nerobro posted:
I like the black bolt xbr solution for the fpv area 1000x better but this is alright as well. I actually kinda want the xbr for my next multirotor, but setting up for production is slow going for that guy. I'm prepping to make some carbon fiber sheets tomorrow, and we'll have the cnc ready in the next week or two, but no cad experience (I was going to use one of the fpv frames from untested prototype). I wonder how easy it would be to design a similar frame. edit: I don't know what you mean VVV moron izzard fucked around with this message at 05:39 on Sep 10, 2015 |
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Sep 10, 2015 05:25
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A Yolo Wizard posted:I wonder how easy it would be to design a similar frame. Really easy. But why do what's been done... nobody has tried a full aero setup...
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Sep 10, 2015 05:37
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A Yolo Wizard posted:edit: I don't know what you mean VVV Copying the aerodynamic X frame... that's not difficult. Doing an aerodynamic airframe, is not so easy. At least at 5-6" prop sizes. The first step I'd like to see, are blocks/fairing over the arms. Streamlining the fuselage, opens up some really neat options. The fuselage could be a dandy lifting surface. But wings are inconvenient volumes, we're used to packing rectangular spaces. If you're looking at aerodynamics, there's a few things you might consider doing.. like mounting your flight controller on edge, and transmitter on edge.. maybe putting your antenna in the wake of your quad, so it's already in disturbed air. Some cameras are "just the size" of the lens housing... between those three bits, your limiting factor for frontal area becomes the size of your battery. 2200mah 2s packs are really slim, why not use two of those... and hang those below the airframe, where an airfoil would be getting narrow anyway. ..... If I go into "how" I might as well not build it myself .. right?
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Sep 10, 2015 07:52
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DreadLlama posted:I know from playing KSP that if one electric turbine does not work, you probably need six. As for my drone, I sent an order to get the plates 3D printed, too, instead of cutting them from GRP. My friend has found someone else at his workplace to cut his plates, and apparently he has layer separation. So he needs to find a solution to this. Online cutting services only do metals, so that's that. Nerobro posted:Almost all quadcopter drag is flat plate-ish drag. This is AWFUL. Anything between your prop and the space behind it is like losing prop area. Having well streamlined arms under the props would cut the drag from the arms by something like fourty times, and that assumes the frontal area is the same. I suppose putting a fin on top would also improve things? Would at least look cool. 
Combat Pretzel fucked around with this message at 12:03 on Sep 10, 2015 |
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Sep 10, 2015 11:58
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Have you considered using q-tip props or ducting them? Seems like it could help with reducing the turbulence and increasing overall efficiency. Or maybe not, depending on all kinds of variables I'm not ever aware of. https://www.youtube.com/watch?v=Cew5JF8q6eY https://www.youtube.com/watch?v=pJEQ4xKFUi4
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Sep 10, 2015 13:38
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My custom prop idea had q-tips, but 32MB ESRAM said that printed props may not survive the stresses. As far as ducts go, that train of thought spawned the electro jet idea. The question is how much additional drag ducts would introduce in forward flight. You could design wing-like parts onto its intake, to improve it and divert more air into it, but whether that'll do anything, IDK.
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Sep 10, 2015 14:35
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Combat Pretzel posted:So my tubular arms and the serrations on the top plate aren't bad ideas, after all? mobby_6kl posted:Have you considered using q-tip props or ducting them? Seems like it could help with reducing the turbulence and increasing overall efficiency. Or maybe not, depending on all kinds of variables I'm not ever aware of. Ducts are great at low speeds. They can add a multiplication factor to the amount of thrust generated. And the tip interaction, if you keep the duct close enough, does big things to increase prop efficiency. Much like flying close to the ground helps curtail wingtip losses, so does a duct. Ducts are also frontal area.... And wetted area. And they weigh something. They also have very strong self righting tendencies, so they make fast forward flight not a thing.
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Sep 10, 2015 14:40
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Nerobro posted:. 2200mah 2s packs are really slim, why not use two of those... and hang those below the airframe, where an airfoil would be getting narrow anyway. You wont get anything flying fast with a 2S battery. Some of the newer micro quads have a thrust-to-weight ratio in the region of 7:1 and you'll never achieve that with a 2S.
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Sep 10, 2015 18:56
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2*2=4
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Sep 10, 2015 19:45
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ImplicitAssembler posted:You wont get anything flying fast with a 2S battery. Some of the newer micro quads have a thrust-to-weight ratio in the region of 7:1 and you'll never achieve that with a 2S. Two 2s packs, in series, gives you a 4s pack. Without the bulk, allowing a much narrower airframe, and less frontal area. Added benefit of running 2s packs, is each cell gets at least one exposed side, so they will cool better. Everyone likes less puffed packs!
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Sep 10, 2015 19:48
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the nicker posted:2*2=4 edit: I can't add today, but it's still rather heavy, isn't it? Thrust-to-weight is way more of a factor with the mini-quads than drag. ImplicitAssembler fucked around with this message at 19:55 on Sep 10, 2015 |
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Sep 10, 2015 19:49
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ImplicitAssembler posted:Right, missed that. So, 4400mah on a racing mini-quad?. We are talking racing quads here, right?. 250 class?. 2S packs in series to make 4S do not add capacity. It becomes 4S 2200. You would need 4 packs in 4s2p to make 4400. The only problem I see with this plan is that it's often difficult to find 2S packs with high C ratings.
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Sep 10, 2015 19:54
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the nicker posted:2*2=4 While that is true, I think more appropriate in this case is 2+2. ImplicitAssembler posted:Right, missed that. So, 4400mah on a racing mini-quad?. We are talking racing quads here, right?. 250 class?. The 4s combined would still be 2200mah, the packs would be in series, so the amp hour capacity doesn't add up, watt hours do add up though. The actual capacity doesn't matter, I used 2200mah because that was the capacity of the 3s pack I had in front of me. 1300, 1500, 1800, whatever capacity you like. 2s packs have the thermal advantage over 4s. Yes 250 class racing quads. Wojcigitty posted:The only problem I see with this plan is that it's often difficult to find 2S packs with high C ratings. If you build it... And it's not like making, or remaking, packs is that difficult. I suspect a design like I'm proposing will either be banned immediately; once a competent pilot gets their hands on it. (that, is not me..) Or everyone will be flying one. Either way, the battery supply becomes a non issue rather quickly. Nerobro fucked around with this message at 20:05 on Sep 10, 2015 |
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Sep 10, 2015 20:01
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Ah nevermind. Good luck.
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Sep 10, 2015 20:11
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Lol nobody is going to ban a good design. If it is significantly better in real world performance then designs will move that way. I will be very surprised though if it produces anything like the advantage you think it will. That said I would love to be proven wrong so please build your design.
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Sep 10, 2015 21:55
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mashed_penguin posted:Lol nobody is going to ban a good design. If it is significantly better in real world performance then designs will move that way. I will be very surprised though if it produces anything like the advantage you think it will. That said I would love to be proven wrong so please build your design. It wouldn't' be the first time. :-) I just need to find some time to do the darned thing. Strength will be a question... I don't think it'll handle bouncing off of trees very well. It's on the list of things for me to do. I'll be happy if it jus tgets people to fit canopies.
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Sep 10, 2015 23:02
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So why not use something like an 850 helicopter tail rotor as a lifter for a quad? With a bit of gearboxing you could have a single motor power all of the rotors. Ofcourse that adds mechanical complexity, but it is probably lighter than having 4 motors and ESCs. Small servos using teleflex cable to control the pitch of the rotors. All that so the arms can be as small as possible while you can run the drive shaft and teleflex through them. Without the need to mount a motor and ESC the arms can be much thinner. Bonus with the rotor pitch control is you can limp home on 3, in case you lose a rotor in flight. And fixed speed, variable pitch should mean the rotors can be kept at the most efficient rpm.
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Sep 10, 2015 23:35
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Deedle posted:So why not use something like an 850 helicopter tail rotor as a lifter for a quad? It's called a Stingray 500.
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Sep 10, 2015 23:59
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I thought that flight drones turned based on spinning up one pair of props while spinning down the other. How does the stingray turn?
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Sep 11, 2015 06:32
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DreadLlama posted:I thought that flight drones turned based on spinning up one pair of props while spinning down the other. How does the stingray turn? You can't change the RPM, but you have individual collective control over each rotor, so you can change the amount of torque generated, which is effectively the same thing.
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Sep 11, 2015 06:46
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