Mr Bird Bones

...a long range FPV drone powered by an 18650. Right at the start you should know I have never made or flown an FPV drone before. This Thing exists with three intentions: 1) I want an FPV drone of my own. 2) I would rather make one from scratch as a learning experience. 3) This Thing will hopefully document my thoughts / mistakes / results for others. 24/03/2022 An update already. I've added a 3D printable 18650 battery holder specific to this build. There's no reason why you couldn't buy one or use the base frame as-is if you're happy soldering flying leads to your batteries but this design should lock in to the frame perfectly, I would suggest with the aid of a Velcro strap or rubber bands.

Drones, drones, drones...

I guess the first questions to answer are why, and so what kind of drone do I want? Why? I hope making and flying one will be fun. Also as I'm fortunate to live in Kefalona part of the year a drone would be useful for exploring and taking photos for my painting. What? There are broadly two kinds of drones. Camera and FPV drones: Camera drones: Designed to be a steady platform for taking stills and video. They tend to be easier to fly, have a good camera, and features that allow somewhat independent movement. For the most part they are slower and less agile, have reasonable endurance, and the controller usually requires the use of a mobile phone or tablet. They tend to be pretty darn expensive if you want one that isn't garbage. FPV drones: While it's possible to press one in to camera drone duties an FPV drone is really all about the experience of flying. Generally lightweight, fast, and acrobatic, with few if any flying aids. You will have to learn to fly an FPV drone and crashes are to be expected. They tend to have shorter flight endurance and camera focussed on providing a 'drone's eye view' rather than quality. The vast majority are flown with goggles for that first person view. Being more a 'hobby' than a 'pastime' FPV drone flying is associated with a bewildering array of options, protocols, and incompatibilities to catch out the unwary. Choice: "It sounds like you should go with a camera drone, why FPV?" Complications aside the price of entry in to FPV is rather cheaper for something reasonable. Once bought the equipment can be used with multiple drones and everything can be modified and upgraded as I go along. Kefalonia is really sunny and I don't fancy my chances trying to fly a drone with a mobile phone. Good endurance and pictures are possible with an FPV drone. I want something small I can sling in a backpack. As I'm after long range rather than a racing drone my choice is likely to be more n00b-friendly, once I learn to fly it at all. Finally, I want an FPV drone because I can make it myself and tinker with it. Armed with these requirements and a bit of research I have enough information to make my choices ...maybe not good choices, but choices.

Mr Bird Bones

Wish list: An FPV Drone. Long range. Small and lightweight, but capable of carrying an extra camera. Decent performance, but easier to fly. Easy to set up. GPS for location and basic return home capability. Keep costs sensible. My own design ...because. It goes without saying that just to get this far took a awful lot of research, getting in to FPV is not for the faint-hearted. I've yet to discover how many idiot mistakes I've made or if I'm going to regret this whole enterprise. If you have the cash just buy an all inclusive kit, if you aren't sure get a camera drone. To simplify here are my choices, feel free to follow along. But be warned I am no expert! I'm going for a "Nano" type as smaller will struggle too much with wind and have poor range. A larger drone would be ...larger, and going the 18650 route isn't practicable for larger drones if endurance is the goal. I also want something that's not too loud. So why use an 18650 when nearly everyone uses LiPos? There are pro's and con's: LiPo batteries are great for light weight and punch. Good for acrobatic performance at any size. But they tend to have poor endurance, and are a bugger to look after and charge if your primary mission is convenience. 18650s are convenient, easier to charge and arguably safer. While lacking punch they can provide much better endurance. That lack of punch and their weight means you have to choose your formfactor and requirements carefully. It seems an 18650 powered "Nano" drone should be perfect for my needs and with a little thought I can offset much of the punch issue. Also running a LiPo is an option.

The Frame

With all this in mind the frame can't be too light. But it needs to support all the necessary components while being tough enough to survive accidents and stiff enough for good flight and camera performance. There are plenty to choose from, the Nanolongrange v2 here on Thingyverse was certainly an inspiration for my design: https://www.thingiverse.com/thing:4818009 But in my arrogant n00bishness I want to go my own way and I think I could do better than other options. If I rely on a similar layout to the flight-tested designs of others I can hopefully avoid mistakes and still hope to make something better by leveraging my own skills. In short Mr Bird Bones is called that for a reason. If you are after lightness, stiffness, and strength, there are a few principles to follow: -Hollow tubes -Curves rather than angles -Holes weigh nothing -Cracks form at sharp corners -Smaller is better, up to a point Note: My design is intended to be the most robust and lightweight frame I could come up with for the parts chosen. As-is you will need to solder a wired connector to your 18650 batteries to mate with the flight controller board. Alternately I have designed an 18650 holder specifically for mounting to this frame as an option. If you use another be sure it will clear the props ...or mount it underneath. IMPORTANT: 18650 holders are NOT keyed so if you go the battery holder route (I am) be very careful when plugging in. Reversing polarity WILL result in a dead flight control board. The radio and main boards I have chosen aren't your only options but you may need to alter the frame. I've included the original 3D files to help. For an 18650 build the suggested motor types and props really are your best options. Of course there will be some compromises for 3D printing, the shape and size of the parts to be used, and aesthetics, but so far I'm pretty happy with the result. Frame: Some experimentation will be needed to dial in your print settings to get the best and strongest result. I would suggest: Material - PLA is fine, ABS or even Nylon if your printer can handle it. Infill - 20% should be a good compromise. Go for a "3D" infill pattern. Support - Yes! Fill hollows with a little "marrow". A "random" pattern for preference. Battery Holder: The same advice. Do be away that the underside has cut-outs for clearance and keying to the frame so print with support and choose an option that's easy to remove. "Wood" filaments may help crash resistance if ABS or Nylon aren't options. If you're going for PLA I would strongly advise curing your print to strengthen it before use. About 45mins at 80c should do.

Parts

There's a dizzying wealth of options and I'm sure I barely have a clue. I'm going to detail what I bought and will no doubt update this Thing as I learn. Banggood seems a good place to buy most stuff but some parts such as motors may need sourcing from elsewhere. Brains: Happymodel Diamond F4 5-In1 F4 1S Flight Controller AIO - FrSky Receiver Motors: Flywoo Robo 1202.5 11500kv x4 (Size 1202.5 at around 11500kv) Props: Gemfan 3018 (A two blade prop for efficiency, check yours fit if not this one!) GPS: Beitian BN-180 (My frame is made for this specific GPS module) Camera: Caddx Ant (16x9 or 4x3 Be sure yours matches your FPV googles) Radio: Happymodel EP1_RX3 (A tiny long range "ELRS" receiver) FPV Goggles: EACHINE EV200D (Seemingly decent and not expensive) Controller: BETAFPV LiteRadio3 - ELRS (To match the radio) M2 Machine Screws -11x5mm and 2x4mm (Titanium lighter than steel but expensive) 18650 Battery Holder - Optional, but a good idea. See image for example of best type. Why these choices? Probably because I didn't know better. But my plan was to try to hit the budget end of decent without falling for bargain-basement garbage, while having options for future builds and upgrades. Here's my reasoning: Happymodel Diamond F4 There are absolutely perfectly good and cheaper alternates. But for a build like this lightness is king and this looks to be the lightest option when running an 18650. Flywoo Robo 1202.5 11500kv As I understand it 1202.5 11500kv spec motors are really your only option for a build like this. Lightness is king, followed by efficiency, and then sufficient power to fly. Flywoo isn't the only game in town but I went for a brand known for quality to save my n00bish blushes. Gemfan 3018 Props If in doubt go with a quality manufacturer. Prop size is important for this build, and as I understand it two blades are more efficient than three. Three blades being generally good for power and increased stability at the cost of sucking battery life. Beitian BN-180 GPS Module Strictly speaking GPS is optional. But for an "explorer" drone anything that may stop you loosing it has got to be a good thing. I believe the Beta Flight software has limited return home functionality, better than nothing if you loose your signal. Happymodel EP1_RX3 Radio After some thought I plumped with an ELRS radio. In part because the module is one of the smallest and lightest available, but also to help futureproof my choices. It seems ELRS is an increasingly popular option. Yes the control board comes with FrSky (one of many standards, sigh) but I wanted ELRS and for this build a communication further than spitting distance. EACHINE EV200D FPV Goggles I'm certainly not paying for Fatsharks! But I also don't want bottom of the barrel either. These seemed a good compromise, are upgradable, and are reasonably small - backpack friendly. I'm still thinking about antennas! BETAFPV LiteRadio3 Controller - ELRS Model On the one hand you don't want to skimp, it's your means of controlling your drone. On the other hand traditional radios are bulky, heavy, and seem to be overkill for me. Got a drone with an ELRS radio? Get the ELRS version of these and be happy. M2 Machine Screws I would suggest the counter-sunk flathead type. Functional using the minimum of material that won't snag. Titanium ones are usefully lighter but as the difference is pence vs pounds stainless steel is fine. 18650 Battery Holder If you decide to use one be sure to source one small enough to clear the props if for some reason you don't print the one I provided, although you could mount the holder under the frame. The provided holder is intended to interface perfectly with the frame, then held in place along with the battery using an Velcro strap or rubber bands. Yes you can glue it but the main board will then be hard to access and as you really should have some battery retention insurance the strap can serve double duty. For ultimate lightness and safety you are best off soldering a GNB27 connector to your flight controller and it's wired mates to your batteries. If you connect up an 18650 the wrong way round it's goodbye flight controller. The frame has rails for a wired battery that can be retained by a strap or rubber bands. Of course much care is required when soldering to a lithium battery and doing so will probably stop you using a standard 18650 charger - part of the point of using this battery type in the first place.

Build

You're going to need to have a reasonable soldering iron with a small tip, patience, having practiced soldering BEFORE you jump in. But it's not beyond anyone with a modicum of competence. For neatness you might be tempted to run the motor wires through the arms. Very fiddly if you try, take care not to compromise strength with cutting or damage the wires. Small rubber bands are your friends when it comes to securing parts. Don't be tempted to use glue, sooner or later you will need to replace a broken frame! You'll also need to familiarise yourself with the software for setting up the flight controller and your radio controller. If you're a n00b like me don't try to over think it. Look for a setup that's similar to yours and copy the settings. Here on Thingyverse I'd recommend checking out these links: Nanolongrange V2 https://www.thingiverse.com/thing:4818009 - Build Video & Wiring The #NanoLongRange https://www.thingiverse.com/thing:4769576 - Controller parameters YouTube is also your friend. No, honest!

Practice

At this point only I'm repeating what seems entirely sensible advice I have read. If you're new to FPV drones it's a really, really, good idea to get a FPV simulator and practice before flying the real thing. One that supports your chosen flight controller is also a good idea. There's a few to choose from and some are free if like me you're on a budget . FPV.SkyDive would seem an excellent choice but regrettably as it's only available on Steam and I have yet to find any other, cough, source I can't vouch for it. No. I don't need Steam, I don't want Steam, and I'm certainly not installing it just so I can practice flying a drone! This trend for having to install such platforms whether I want them or not is an unpleasant trend I don't like at all.

Further updates as I get on with building my own drone...

Found 5 3D-models for “bird bones” across many websites

Abstract Bird

Bird Macaw Skeleton

Bone bracket for the Skull bird house

Mr Bird Bones the Long Range 18650 FPV Drone

Raven Skull