Updated on February 15, 2022 As an endurance frame, this build aims to maximize flight time but also optimize signal reception both for radio control and FPV image. At 237g AUW with a 4S 1100mAh lipo, the build relies on the efficiency from low KV 1404 motors spinning 4 inch bi-blades. An onboard HD split-style camera serves to capture the HD footage although there is headroom for a lightweight external HD camera (Insta360 Go or Naked GoPro) in lieu of the split HD camera. In addition to the build itself, we’ll be looking at the tuning and filtering strategy as well as a weight analysis so you can have a better idea of how to approach your own sub-250g build. Build Log Tuning & Filter Strategy Weight Analysis Build Log Since this is a uni-body frame, there is no assembly required for the main plate. I have come to rely heavily and grow confidence in today’s AIO FC’s. In particular, I have been gravitating to the Flywoo Goku GN745 F7 AIO flight controller with 40A BLHeli_32 ESCs rated for 2-6S. It’s likely overkill for a low amp draw efficiency build, but better to have more than less. There are also few F7 AIO’s with 32-bit ESCs and onboard blackbox from reputable manufacturers. I got lucky in finding these T-Motor F1404 2800KV “FPVCrate Edition” motors. The lower KV will significantly lend to the efficiency in spinning the HQProp T4x2.5 bi-blades. Click here to download STL files for 3D printed parts compatible with the Shinobi Mk1. A 35V 330uf capacitor at the lipo has proven sufficient to mitigate noise for this 4S build. Be sure to use only good quality low-ESR capacitors from proven brands like Nichicon or Rubycon. I am using 16AWG silicone wires for the lipo harness measuring approximately 2-1/2 inches. As always, consider conformal coating all exposed electronics as a safeguard against accidental short circuits. Widely used by FPV hobbyists, MG Chemicals (422C) silicone conformal coating also comes in a UV sensitive version which will illuminate under UV-A light (black light) to easily identify areas which are not coated. For the HD footage, I am using a Caddx Baby Turtle Whoop Version capable of capturing 1080P 60FPS footage. As mentioned above, given the lightweight nature of this frame and particular build, there is room to use an external lightweight HD camera such as the Insta360 Go or Naked GoPro while remaining below the 250g threshold. The camera cage measure 20mm wide, so to ensure the tightest fit, I’m squeezing in 0.5mm TPU spacers between the camera and the cage. Note that the Shinobi Mk1 camera cage is large enough to secure a Caddx Tarsier. However, the camera cage will not hold the larger Runcam Hybrid. For the receiver, I’m using a TBS Crossfire Nano with the stock antenna held in the optimal vertical orientation and its ground element (bottom part) clear from carbon fiber. The Crossfire antenna is held in the vertical orientation with standard antenna tubing which can be purchased at most RC stores, Amazon, or eBay. The tubing is held in place with a TPU mount that doubles as a rear stack standoff. For endurance and in particular long range builds, I have come to count on the Matek VTX Mini. This little powerhouse weighs only 5g but can output clean 800mw video. It is capable of PINIO control meaning you can power the VTX via switch on the radio which is ideal to minimize VTX heat while the GPS acquires satellites. The onboard microphone effectively lets you know if the motors are behaving abnormally. And the MMCX connector provides a variety of very effective direct-connection antenna options. In an effort to mitigate signal shadowing by the frame which is a key consideration for endurance and long-range builds, I prefer to mount my control and video antennas along the sides of the fuselage rather than the conventional placement out the rear of the frame. But by doing so, I need to orient the Matek Mini VTX such that the buttons are now exposed dangerously close to the lipo harness which may forcefully shift in a crash. If the harness pushes these buttons, it may change the VTX channel or power settings. I have glued these buttons into place for safety. The GPS module is also from Matek. I’ve found the Matek M8Q to be a very reliable GPS with noticeably much faster sat locks as well as more reliable locking that doesn’t fluctuate compared to other GPS modules. For the VTX antenna, I am using a VAS Minion Pro with a 90 degree MMCX connector. Arguably, VAS has been a long-time trusted source for FPV antennas and this Minion Pro does not disappoint. I’ve sheathed the stem with a couple layers of heat shrink so it remains upright. A TPU printed rubber band holds it in place. For endurance and long-range, bi-blades are really the most efficient route. HQProps T4x2.5 bi-blades are being used for this build. Last but certainly not least are the super bright Pico Rainbow RGB LEDs from Tiny’s LEDs. Do they serve a purpose? Not really. But man, do they look cool. AUW with a GNB 4S 50/100C 1100mAh XT30 lipo is 237g. Tuning & Filter Strategy Click here to view the Blackbox Tuning Guide. Since this is a deadcat frame, I prefer to input a custom motor mix rather than selecting any of the default Betaflight motor configurations. For reference, the motor-to-motor measurements are as follows: 1-2 / 3-4: 114mm 1-3: 126mm 2-4: 143mm The following custom motor mix was calculated using the Multi-Rotor Motor Mixing Calculator. Apply the custom motor mix through the CLI command line. mixer custom mmix reset mmix 0 1 -0.881 0.795 -1 mmix 1 1 -1 -0.795 1 mmix 2 1 0.881 0.795 1 mmix 3 1 1 -0.795 -1 save As would be expected with flanking vertically oriented control and video antennas, the gyro_scaled traces on this build is not the cleanest. This is not meant to be an acro build, therefore the cleanest noise profile is not as urgent. I would not recommend tuning your filters without the antennas (or any component for that matter) mounted and oriented just as you would intend for the build. By doing so, you are effectively tuning to a different build and the motors will run particularly hot since the filters are now running noise that was previously not there. After filters, the noise profile for the build is acceptably clean. Despite the noise profile in gyro_scaled, I was still able to achieve an acceptably clean gyro trace using minimal filtering. As mentioned, this strategy relies primarily on RPM and Dynamic Filtering. If your ESCs are BLHeli_S, you can use third party firmware to allow for RPM Filtering or compensate with additional notch filtering. Ultimately, you can enable sliders and incrementally reduce filtering to its optimal level (be sure to check motor operating temperatures often). Based on the filtering, the following PIDs and Feed Forward settings were used. Weight Analysis The following breaks down the AUW of 237g of this build by all the individual components. It will come as no surprise that the lipo and motors might account for half of the AUW. In this case, 55% to be exact. But for sub-250g oriented frames, the frame itself accounts for a much larger portion than its 600g+ five inch brethren. As much as 15% in this case or the third heaviest component in the build. Chart by Visualizer The following chart sorts all of the components by weight. Chart by Visualizer The next biggest take-away is the wiring, connectors and solder take up as much as 6% or 13g of this build. That is a lot. Generally, I personally like to use connectors since I am often trying out new components. Included in this category are motor and prop screws which together may be another 5g. And most significantly of course is the lipo itself accounting for 38% of the AUW. Note that the lipo used in this build is a lightweight GNB HV 4S lipo weighing an astonishing 90g (at storage voltage). To save even more weight, you could consider GNB’s lightweight 3S version weighing a measely 73g. It should be noted that these lightweight lipos typically lack high C ratings. This is not as much of an issue with low amp draw sub-250g endurance builds but may be problematic for amperage demanding acro. Ultimately, the Shinobi Mk1 provides a variety of options for approaching a sub-250g endurance or micro long range build. The purpose of this log is to provide ideas and inspiration for you to come up with your own perfect setup. 73 All products mentioned and used in this build log were purchased at retail. All links to product websites are non-affiliate / non-commission and no solicitations were made by companies to the author to promote these products.