Category Archives: Airplanes

First testflights of my DIY solar plane

This is a new project I have been working on for the last couple of mounts. A solar power autonomous plane. My goal with this project is to make a plane that is capable of sustaining powered flight using solar power.

My main sources of inspiration are the solar planes that Daniel Riley from RCTESTFLIGHT made: https://youtu.be/SwbJJoe09DI and also this project by Magnus Lindström: https://discuss.ardupilot.org/t/solar-rc-plane-300km-7h/60981

My plane is scratch-built for the purpose of being a solar plane. Completely my own design. It has a large wing area for mounting solar cells and is relatively lightweight. The wing is built with depron and a wooden wing spar. It has a flat bottom wing profile that is similar to the classic Clark Y. The fuselage is built using balsa wood, and a fiberglass fishing pole as the tail boom. The wingspan is 2.5 meters. Total flying weight without solar sells is exactly 2 Kg, with gives a wing loading of about 24 grams per square decimeter.

The plane is using a 750 KV drone motor spinning a 13 inch propeller. This is powered by a 4-cell Li-Ion battery made of Samsung 50E 21700 cells. I am using a Mateksys 765 wing flight controller running the ArduPlane software. The plane is capable of flying GPS waypoint missions fully autonomously. There is also an airspeed sensor with a pitot tube mounted in the wing for improved speed control, and therefore improved efficiency.

I have not yet installed the solar cells on the wing. I wanted to do some flight testing first, since the solar cells are fragile and expensive. The plane is very efficient. In calm wind conditions the plane consumed 1730 mAh while cruising at 10 m/s at a constant altitude for 45 minutes. This results in an average consumption of about 2.3 Amps or about 35 Watts. Power consumption is slightly higher in windy conditions. The added weight of the solar cells on the wing will also increase power consumption slightly.

I will be using 36 Sunpower Flexible 5×5 E60 cells on the wings. The theoretical maximum power output is about 130 W, but the actual power output will be less than that. I will also be using a Genasun GV-5 charge controller that has a maximum power output of 75 W.

Cruising autonomously into the sunset at 10m/s and 50 meter altitude
A laptop running Missionplanner is used as the groundstation
DIY dipole antenna for the 433 MHz telemetry link to the ground station. Good antennas are necessary to achieve a reasonable range with only 25 mW power, which is the maximum allowed here in Sweden.

Bush Beast 4 – My new RC Bush Plane

An iteration of my previous design, the Bush Beast 3. This plane has larger control surfaces and larger flaps than previous models. I also made a new landing gear design based on Mike Patey’s Scrappy plane. Of course, I still have all the features of my previous version, including reverse thrust, a DIY light system, and also a DIY gyro stabilization system to make it fly stable in high wind conditions.

More info here: The Bush Beast 4 page

Bush Beast 4

More autonomous landings with my ArduPlane project

I have been doing some more flying the last months, finetuning and trying to improve the autonomous flying capabilities of my ArduPlane-plane.

Here I have made a page about this plane with more info in images: 2020 ArduPlane project

In this video I have installed an airspeed sensor (pitot tube) and a downwards facing LiDAR rangefinder. Thiss allowed the plane to land more predictably.

In this video, I think I have gotten the landings to work pretty well. Here I am flying a butifull evening with no wind. I will continue to experiment to test in other conditions with more wind in the funire.

ArduPlane autonomous flight

A fully autonomous takeoff and landing demo. The plane is designed and scratch-built specifically to be flown by the ArduPlane system. It has large control surfaces and a landing gear with a lot of suspension travel to work well on my local flying field with is a bit bumpy. My goal with this project is to create a plane that can fly waypoint missions and takeoff and land reliably in autonomous mode. This video was recorded in September of 2020, and a will continue to experiment and improve the plane. Lidar altitude sensor and airspeed sensor is comming…

I built this plane at the beginning of 2020. I started making a few first test flights in the spring. Then in April, almost exactly one year ago, unfortunately, some technical problems caused the plane to crash. The Chinese Pixhawk-clone I was using suddenly stopped working at an altitude of about 50 meters. The plane made a steep dive at high speed into the ground. The autopilot was fried, and it probably sent out full battery voltage on the 5V-bus in the process because the GPS, airspeed-sensor and telemetry-radio also get destroyed. I have a log-file with a large current-spike happening half a second before it died, in the air. The battery, motor, ESC, and all servos survived. But It was still a major setback for the project.

Crash site after the in-air autopilot failure.
Burned chinese Pixhawk-clone that suddenly stopped working in the air.

3-4 mounts later I decided to repair the plane and order new electronics for it. I am using a different Pixhawk-clone now, and I have made many successful flights with the plane. It has now logged over 10 hours in the air.

Making LED light systems for RC planes

I have been experimenting with making my own LED light systems for RC planes for a while now. I first made my “RC plane hub” for one of my planes in 2019. It was a combination of a LED light system and gyro stabilization. More about that here: http://axelsdiy.brinkeby.se/?m=201911

Later I wanted a small simple standalone system that could easily be installed in any plane. I first made some experiments by just connecting a couple of transistors and LEDs to an Arduino Nano. After a bit of prototyping I made a custom PCB with a ATmega328 processor and some MOSFETs for controlling the LEDs.

V1.0 of my LED controlled board.

The idea is that this board is connected to the full battery voltage of the RC plane, and the outputs are connected to the LEDs. The LEDs themselves are connected on groups of three in series with a current limiting resistor adjusted to the LED type used and the battery voltage. The ATmega328 processor (same as Arduino Uno and Nano) reads a standard servo signal and controls and flashes the LED outputs in different ways depending on the input. This alows the pilot to control the LED from the RC radio.

I usually fly my RC planes on 4 cell Li-ion batteries. They are just over 16 volts fully charged and 12 volts when discharged. This causes the LEDs to be bright at the beginning of the flight and pretty dim at the end. Therefore I usually connected one of those small switching adjustable DC-DC converter boards between the flight battery and my LED board to convert the input voltage to 12 volts. When also adjusting the current limiting resistors for the LEDs to 12 volts this works quite well.

For the LEDs themself I use cold white surface mount LEDs for landing lights and strobe lights. I have made my own custom PCBs for them, as can be seen in the video above. For the colored navigation lights, I use standard 5 mm LEDs, of the brightest type I can find.

cold white surface mount LEDs for landing lights and strobe lights.

Later I made a new version of my custom LED controller board with a built-in fixed 12V switching regulator. Otherwise, it is the same processor, MOSFETs, and software as the first. I also skipped the indicator LEDs for each channel to save space on the PCB.

The new board is 60 x 25 mm. The 12V regulator can supply up to 3A to the LEDs. The MOSFETs can handle up to 3A each. Whish is a lot more than needed. The input voltage to the board can be up to 40V, or 10 li-ion cells in series. If the input voltage is lower than 12V the LEDs and the board will still work, but the LEDs will no be as bright.

Here is a link to my Arduino code: http://brinkeby.se/downloads/RCplaneLightSystemV2.zip

Feel free to use and modify the code as you like. This code can also be used an any standard Arduino Uno or Nano, not just my custom board

Here is my EasyEDA project with the PCB design: https://easyeda.com/editor#id=|d7bd0d7576e04ff88b89458a67529799|d44eedf4a12541269b71d3d20c136a3d

More winter flying

Another video with more winter flying. This time with a few different airplanes. Me and a couple of friends flying at my local RC club: FK Gamen. It is actually pretty uncommon that we have this much snow here where I live. Usually, it just comes a few centimeters of snow that melts away the next day. But this time the weather was perfect. Lots of snow, low winds and sunny.

I found it interesting to experiment with different ski-designs. The planes with smaller skis struggle to stay on top of the soft snow. In the latter part of the video I have made new longer skis for my plane that work better in the soft snow.

Winter flying with skis

Made a set of skis for the Bush Beast 3. This video shows the first few testflights with them.

The skis are made out of 1.5 mm plywood and covered with Oracover on the underside for low friction. I piece of 1 mm piano wire is bent around the main landing gear and makes sure the skis are oriented the right way.

Bush Beast 3 electronics

Here is a video of me assembling the main electronics board used in my Bush Beast 3 RC airplane.

A Teensy microcontroller is used to read a decode an S-bus signal from the receiver and make all the servo signals. It manages servo mixing and gyro stabilization, as well as controlling LED lights on the plane.

More info about this, including schematics and code can be found on the Bush Beast 3 page here: Bush Beast 3 page

There you can also find some build-images

Two new airplanes

I got myself two new airplanes this summer at an RC plane auction that was organized at my local RC flying club FK Gamen.

The first one is a J3 Cub ARF model by Thunder Tiger with a wingspan of about 2.2 meters. The model came with a 4-stroke nitro engine that I have replaced with an electric power system. I will make a new landing gear with suspension and fix the motor cowling. I will probably add some kind of gyro stabilization also, this plane is surprisingly unstable in windy conditions.

The second plane is a Flair Magnatilla. The wingspan is about 1.6 meters. This is my first airplane with a nitro engine. A 4-stroke Saito. I will probably add a steerable tailwheel and make a few other adjustments over the winter.