What happens when multirotor world meets flying wings? Flying ZM250 without arms is born. Today we will take a look at a new example of German Engineering: Flybot Flux Freestyle FPV Flying Wing
Weather like this happens only a few times a year: raising fog, low sun and another layer of clouds… And very little wind. To be honest, when I went to the "airfield" I did not expect to use my Mini Drak at all. The fog was too dense and too low. But then it raised and holes appeared… Awesome…
- Airplane: Ritewing Mini Drak
- HD Camera: RunCam Split Mini 2
Let's cut to the chase: my final review of ZOHD Nano Talon is: this airplane is crap. Just like that. Period. It might be good looking, it might be spacious inside and quite well thought through but it lacks one thing: it does not want to fly well. As simple as that.
As long as air is calm and there is no wind it's kind of OK. You can even have some fun with it. Yaw still sucks, a roll is strange but it's OK. But as soon as wind appears and Nano Talon has to fly through the disturbed air, it is over. This thing just does not wants to fly straight. Always tipped to one side, unresponsible and wobbly. Nope nope nope…
Yestarday I wanted to make a first "real" range test of my DIY LRS system. "Real", because RX was supposed to be on a flying wing, but only as an passenger. Actual control was supposed to be happening via FrSky X8R. Crossbow RX was only to measure RSSI and check for failsafes.
It, well, did not ended up very well. Just watch the video.
I’ve described my Dropship Glider Project here. Previous weekend I finally tested its ability to glide when dropped from a drone 50m above the ground. And well… to be honest, I failed hard this time. Just see this short video from FPV camera:
Dropship survived two drops. After second one, AIO camera/transmitter combo got damaged. Continue reading Project “Dropship glider” – failure #1
When I saw this video from rctestflight I knew I will build something like that for myself. A voila, few months later it is done. Here is Dropship Glider.
It is 29cm long with 20cm wingspan. Weights 97g AUW and has 21g/dm^2 wing loading. So, in theory, should glide. Somehow… If I got center of gravity right. And did not made ailerons too big. Or…
Delta 6mm Depron "wing" is attached to 6mm carbon fiber rod and has some quite big dihedral: 15 degrees.
The biggest problem was radio link and mixer for ailerons. I could not use my Taranis: I need that for a carrier and only radio control link I had was EM-16 with PPM output only and no way to setup any kind of mixer. The radio just has no "features" like that…
So, took one Arduino Pro Mini and wrote short program that acts as PPM decoder and mixer for ailerons.
- power is supplied by 1S LiPo taken from my Tiny Whoop
- FPV AIO Eachine TX02 also taken from my Tine Whoop
- 5V is supplied from cheap, regulated, step-up converter
- 3rd servo is to release tether
First flight, or rather drop, tomorrow. There will be a video from the event of course…
Chasing airplanes with drones is cool. Do not try to argue 🙂 But airplanes are cool too. So here is a short video my friend shoot some time ago:
Drone pilot: Krystian
Flying wing pilot: me (I had no idea I was chased)
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:
- Motor was overheating. Just like that
- 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
- It was big and slow and was not giving enough fun
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.
One of the things that INAV was missing, was a decent support for Pitot tubes, or more generally speaking, airspeed sensors. Autonomous flight, or landing, without knowledge about airspeed can easily lead to a stall. Stall can lead to crash. A crash leads to rebuild. Rebuild of big airplane is a nightmare. Although, for some time now INAV was able to use digital PX4 Airspeed Sensors (I2C, based on MS4525), but they are quite expensive and airspeed was only reported in blackbox logs. Not very useful, right?
Now, this is changing. Next release of INAV (1.8 probably) will bring at least support for much cheaper, analog, APM Airspeed Sensor based on MPXV7002 chip. Although some simple additional electronics (2 resistors to be precise) will be required, but this pitot tube should be available for all flight controllers with free ADC input (Current or RSSI). Fancy ADC remapping will allow to use any ADC without built in dividers (Vbat has dividers so can not be used) as pitot input.
More than that, INAV 1.8 will (or at least should) bring PID scaling according to airspeed for fixed wings. This should result in better handling on both low and high speed.
As you can see on the picture above, APM Airspeed Sensor is already installed on my small flying wing and is waiting for first flight tests this weekend. Logging only for now…
It's official: next release of INAV (1.8 or maybe 1.7.2) will incorporate an automated landing procedure for fixed wings. I was already writing about it 2 weeks ago, but now new code has been merged back and will be released.
Bear in mind, that this is not "state of the art" landing yet. It's rather a simple solution that can be used in emergency situations that will not crash an airplane, but rather put it on the ground without crashing. Procedure is quite simple:
- When Return-To-Home or Failsafe with RTH is engaged, go to Home position
- When Home is reached, start to loiter with defined radius and descend. Descent speed is limited to
nav_landing_speedwhen altitude is above
nav_land_slowdown_maxalt. When altitude is below
nav_land_slowdown_maxalt, vertical speed is scaled down to one fourth of
nav_land_slowdown_minalt. So, on using default values, vertical speed is between 2m/s and 0.5m/s
- During descend, airplane is not allowed to raise throttle above
nav_fw_cruise_thrwhen nose is up. This is to prevent airplane from gaining horizontal speed
ROLLaxis is locked to 0 degrees,
PITCHaxis is locked to
nav_fw_land_dive_angle(default is 2 degrees) and motor is stopped when
MOTOR_STOPis used or put to IDLE when
MOTOR_STOPis not used. This puts airplane into a shallow dive to the ground
That is all. Airplane should glide last few meters to the ground. Most designs should be able to do it without a problem. My testing platform did it like that:
Since there is no auto-disarm procedure yet,
MOTOR_STOP is recommended to prevent propeller from breaking and motors/ESC from burning.