Mechanical Bat: Bat Bot B2

Nature gave ability to fly to birds, insects and some mammals quite some time ago. We, as a species, learned how to fly only very recently. And let's be honest here. We are not very good at it. We need machines to fly. Any our machines are not very efficient at that task. They require huge amounts of energy to do it, need maintenance and make a lot of noise. Look at birds and bats. They fly for longer using less energy. And they do it with grace.

This is project that caught my attention only today: mechanical bat from University of Illinois called Bat Bot B2.

Bat Bot, from Caltech von PopSci

Take a look at that video. Maybe it's not stable or capable of longer flights yet, but I'm really, really impressed. One day I would really like to have an UAV like that!

Via Hackaday

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Relaxing Winter FPV Session

Winter is not the best time for FPV. Day is short, it is cold, it snows or rains most of the time. But sometimes, when sun is shining, there is a slim window ofopportunity to just go outside and fly. You will get cold, batteries will last shorter, but it will be worth it.

Some people will say it is boring. For me it's not boring. It's 100% relaxing…

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INAV: Launch mode video tutorial

One of the best new features of INAV 1.4 was Launch assistant mode (NAV LAUNCH). It greatly simplified the process of hand launching a fixed wing. All you had to do was to throw it into the air. INAV detected the throw, engaged motor(s) and stabilized flight and kept constant climb rate in the initial flight phase. INAV 1.5 will make it even better: it will also allow swing launch!

Since INAV 1.5 should be release in next 2 days, and there is very little info on INAV Launch mode, I’ve decided to create a short video showing how to do it.

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3D Print Timelapse Video

Few days ago I've decided to do something new: timelapse video of a 3D print. It's kind of fascinating to watch extruder places layer after layer of molten PLA… too bad it's taking so long to print something bigger…

  • Printer: Malyan M150
  • Thing: 35 deg RunCam HD / Mobius stand for mini-quads
  • Filament: PLA
  • Speed: 50mm/s

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INAV is learning to do mini-quad racing too

Let's be honest: in terms of mini-quad racing there is Betaflight (probably also Raceflight but I've never flew it yet, so will not comment on its flight performance), long long gap, and then it's everything else including Cleanflight, LibrePilot, INAV etc.

Originally INAV concentrated on "big" UAVs with GPS capabilities. After all NAV in name stands for Navigation. Mini-quads and acro performance were left alone, and once again, let's be honest: comparing to Betaflight, it sucked. It was possible, I've even written a short tutorial how to set it up, but it sucked.

Luckily, it is changing. INAV 1.2 had brought some improvements like Iterm limiting and acceleration limiting, and Acro flying in INAV became very nice. Small revolution, or maybe bigger catch up, is planned for INAV 1.3: asynchronous gyroscope, accelerometer and attitude processing. I've been working on it for last few months and results are very promising: INAV can drive a mini-quad with Betaflight comparable performance. Like this (please remember I'm not the best pilot!)


  • PID task frequency: 1kHz
  • Gyro task frequency: 2kHz
  • Accelerometer task frequency: 120Hz
  • Attitude task frequency: 100Hz
  • Frame: Reptile X4R 220
  • Motors: EMAX RS2205 2300KV
  • Propellers: DALprop TJ5045
  • Flight controller: SPracingF3
  • Firmware: INAV 1.2 with custom changes

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Marabou Stork: fixed wing FPV platform

Marabou Stork, my Depron/Carbon/3D Printed FPV airplane is officially done. Although it had first flight a week ago, some technical problems postponed full feature trials until yesterday. I would not call it a "huge success", but it was fine.

Here is a video from some FPV flying:

After around 1 hour in the air, here are some conclusions:

  • Wing is closing to it's limits. Originally it was designed for an airplane that weights around 500g. Marabou Stork weights 900g. Do not get me wrong, it still flies good, I really love KFm-2 profile on it, but you have to start to remember about things like air speed, specially during turns: too much yaw, not enough speed and bam, you have stall. It's easy to recover, no problems there, but last years model (the same wing, less weight) was free of it
  • Neo-6m GPS is, hmm.., crap… I have to update to Ublox Neo-M8 as soon as possible
  • INAV is unable to process GPS altitude and barometer altitude simultaneously: altitude jumps up and down like crazy. For now, the only solution is to disable either baro or GPS altitude component from computations. It's simple and I will try to write few words about it next week
  • Did not tested fixed wing navigation features of INAV yet. Reasons: two points from above
  • Boscam TS-351 200mW 5.8GHz transmitter with crappy clover-leaf antenna behaves much better than expected. I had excellent reception on my Skyzone Sky-01 at 1km and had to return due to RC link RSSI warnings
  • I'm disappointed with FrSky X4R range. Looks like 1km is a safe side limit here. RSSI was dropping to 40 and did not wanted to push it further. Probably it's because crappy antennas. They are equipped with simple whips, not dipoles like X8R for example. Next week I will try connecting 2.4GHz dipole to X4R and will give it another try

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