Here are Two Aircraft I have built with full Autopilot complement. One is based on a commercially available airframe kit, the Lanyu -100, while the second is a from the ground up design. I will give a little info on each just to show what can be achieved with very low cost.
The Lanyu-100 is a basic kit, not the most robust, and so required some simple work to strengthen the fuselage and wings. However, the basics are very good, and you could not purchase the wood raw materials for the kit price, so good value. It is a basic ply and balsa construction, covered with shrink on coloured covering. This Aircraft is called 'HornBill' and was so named as a UAV to be flown in the African Bush, in Namibia, in a trial to test the use of UAV's in TRacking animals fitted with RF tags, and as an aid to the National Parks anti-poaching campagne. This project was partly sponsered by the World Wildlife Federation (WWF) and executed by us for the Namibian Ministry of Environement and Tourism, tasked with wildlife conservation in Namibia. Altogether 4 fully autonomous flights, lasting up to 1 hour, were flown over the Waterberg National Park in Namibia, located at 1600meters ASL, and about 30deg C. A chase helicopter followed HornBill over the 4 flightplans to monitor its progress, with the ground pilot taking the plane up, climbing into the chopper, following the flight plan, returning and landing the plane manualy again. Altogether it was a resounding success, with the tag detection and tracking working flawlessly. The next step being considered is the fitment of an IR camera to aid in detection of poachers, especially at night. Watch this space....
Hornbill basic Specifications.
- Wing Span - 2.4meter
- Engine 55cc Twin Boxer.
- Weight 15kg with 3liter gas
- Max TOW - 17Kg
- Endurance 1H 40minute with 0.5 liter spare @ 24m/s
- Min safe speed 14m/s @ 16deg AoA.
- Stall speed 10m/s @ 25deg AoA.
- Max flight speed - 34m/s
it was a lot of fun! See the report:
The second Aircraft was designed from the ground up, a full 3D model developed on CAD, and designed to be made from good aircraft grade ply. However, it was built with plain Marine ply in the end, as and exercise in cost reduction. All the fuselage parts, sides, ribs, bulkhead, etc, were all extracted from the 3D model, and then cut on our own CNC router, and then all glued together. It is called GUPPY, from its somewhat bulbous belly, giving it unprecedented payload space and capacity, nicely under the center of gravity. It was designed to carry a hi resolution camera , which was subsequently flown to create geo-referenced imagery for the Quarry miners, as well as for the Salt Works. The quarry miners used the images to create a 3D image from which they are able to determine the delta in image 'volume' from last months image, therby determining the volume of ore mined. The Salt Mines use the image to determine the levels of algae growth in the saline evaporation pans. Excessive algae growth can destroy salt production, so the images assist in timeous intervention. Eventually we will fit GUPY with an IR camera to do the long endurance night flights for the anti-poaching trials.
The wings for GUPPY are a straight Clark-Y profile, 600mm chord, 15% thickness, foam core and vacuum bagged. They are each fitted with two Junker Flaperons, each with own servo for redundancy.
These wings give tremendous lift performance. You will see the Pitot sticking out forward of the wing leading edge. The Horizontal Stabilizer is a fully flying surface, INVERTED Clark-Y profile. It is inverted since we can land and takeoff at pitch angles up to 28degrees, at airspeeds down to 14m/s, and so need a lot of 'downlift' on the tail to push it down at the low airspeeds, for STOL performance.
GUPPY Basic Specifications:
- Wing Span - 2.8meter Clark Y 14%
- Wing Chord 600mm +80mm for Junker Flaperon
- 2 Flaperon per wing, each with own servo
- Horizontal stabiliser - 450mm each half span Clark Y 12%
- Horizontal Stab Chord - 220mm
- Each stab half fitted with own servo
- Engine 100cc Twin Boxer. (3W)
- Weight 26kg empty
- Max TOW - 42Kg
- Max Fuel - 8.5liter
- Endurance 5hours with 0.5 liter spare @ 35kg @ 24m/s
- Min safe speed 12m/s @ 20deg AoA.
- Stall speed 10m/s @ 25deg AoA.
- Max flight speed 42 m/s
In both cases the autopilot fitted is one designed by me, with all software written by my good wife.. The autopilot is called the 'NamPilot' and is based on multiple modules, namely:
AUTUPILOT: an AVR processor based module, 8 PWM inputs from RCS, 7 PWM outputs to servos. This module does the full flight stabilization and navigation/guidance for auto flight, and stabilization for manual flight with autostabilization - mostly used when tuning the control loops.
IMU - Also AVR based, with 3 axis Gyro's, accelerometers and a Bosch I2C pressure sensor.
AIRDATA UNIT: Also AVR based, a smaller processor, with another Bosch I2C pressure sensor, and an analogue static pressure sensor ( freescale) and a Dynamic pressure sensor for airspeed. (Freescale)
MAGNETOMETER: Also a smaller AVR processor, with a Honewell 3 axis magnetomet, configured in a balancing bridge circuit, ie, the null strap in the device is used to balance out the ambient magnetic field in a control loop. This gives VERY accurate performance, with almost no temperature drift at all, the bain of magnetometer performance!
All the sensors modules are fully temperature compensated and calibrated, and the IMU offsets all calibrated out or compensated in software.
Have fun reading !
Joe and Gisela
We have also developed a full ground control station with all the bells and whistles - you can see it in some of the attached pics.
And here are some videos of the whole story....
The GCS is a Composite cased unit, PC based, operating of 12V DC., with antenna and datalink built in. An external Yagi tracking antenna stands on a tripod on the ground.
Autopilot. IMU and associated electronic modules.
Trust you liked what you saw!