Marabou Stork decommissioned

Depron airplanes are easy to build, but also do not last long. Few weeks ago I decommissioned by Marabou Stork. It did not crashed, it was flying almost fine, but it had at least a few problems:

  1. Motor was overheating. Just like that
  2. Wing that I originally designed for something weighting around 450g, now had to work with twice that much weight. Take offs were, at least, problematic
  3. It was big and slow and was not giving enough fun

Marabou Stork Depron FPV airplane

So, to paraphrase Monty Python:

This is a late marabou stork

It's not a complete end of this design. Wing is still in pretty good condition and I have a plan to reuse it in experimental twin-motor design. But that later this year… In a mean time, last video footage.

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INAV can do automated landing on fixed wing?

Those of you how subscribed to my YouTube channel should have noticed, that I got an interest in automated landing of fixed wings after RTH in INAV. And the sad truth was that, well, INAV up to 1.7 was unable to do it right. When landing after RTH was enabled (nav_rth_allow_landing = ON) and it was enabled by default, airplane usually started a 20 degrees dive to the ground. One does not has to be a prophet to figure out how it ended.

For example like this:

If not manual override, that would end up in a beautiful crash and probable full rebuild of an airplane.

Luckily, that motivated DigitalEntity enough to something about that, and yesterday I was able to perform (probably the first one ever) a controlled descend after RTH that ended up with an airplane on the ground without any damage. With enough optimism one can call it even a landing. This is how it looked like:

Current implementation is still far from perfect. Although it does not crash, it has a few small problems:

  • No disarm. Throttle is open all the time
  • It happily ignores speed. Both ground and airspeed
  • It also ignores wind, heading and so on

But, to be honest, this is a nice progress. Stay tuned for more changes here, since I’m planning to work on it in the near future.

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Marabou Stork reborn

It took me quite some time, but I've finally rebuilt my Depron FPV airplane Marabout Stork after last year's crash.

In theory, all I had to do, was to replace nose section. At the end, it turned out, that I should also reinforce wing mount, redo FPV system and replace flight controller. So, full list of changes:

  • Rebuilt nose section that is longer than original by 30mm
  • Full sized MinimOSD was replaced with Micro MinimOSD to save some space
  • Flip32 flight controller was replaced by SP Racing F3 and external BMP280 barometer
  • INAV 1.7 baby!
  • Various reinforcements, mainly around wing mount

Weather conditions in above video were far from perfect. Wind speed around 50km/h made everything hard.

It still awaits for new GPS module, since Ublox Neo-6M is really, really, really crappy solution…

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Marabou Stork: Depron airplanes do not last long

Marabou Stork, my Depron FPV airplane had a bad luck. Few weeks ago, when I was testing development version of INAV, it crashed during take off. Poor accelerometer calibration combined with a software bug resulted in heavy roll 2 meters above ground. As a result, whole front section was smashed. Everything else more less survived. Luckily, winter is coming, flying season is more less over. I have few month to rebuild the nose and glue it back into place. With some extra reinforcements.

marabou stork crash 2

marabou stork crash

While Marabou Stork awaits new nose, I still have some footage to show…

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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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Marabou Stork: FPV airplane maiden flight

For the last few week I’ve been little busy building my next fixed wing UAV: “Marabou Stork” Depron/Carbon/3D Printed airplane with pusher prop build for FPV. It’s improved version of “Red Cruiser” model from last year.

marabou stork depron airplane

marabou stork depron airplane 2

It’s equipped with KFm-2 wing, Turnigy D2826-6 2200KV motor, APC-E 7×4″ propeller, 2700mAh Lipo battery, FPV setup with MinimOSD and RunCam PZ0420H camera. And Flip32 running INAV for stabilization and navigation (no GPS yet).

As you can see on a video above, it flies. Even pretty well. It needs some tuning, but have big potential. Unfortunately elevator malfunction grounded it after few minutes in the air.

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