Blackburn Flyers Newsletter
Issue 17 – September 2015
As previously reported our build team are making (modest) progress and we now have the basis of the empennage and one set of outer wings. However we are behind schedule. Holidays have been an issue but the main limitation at the moment is the amount of space available and the fact that the glue takes 24 hours to set, we’re getting so quick we can use all the build space in two hours and then we’re stalled.
Highlight of the week’s efforts was the total disintegration of Mel’s safety boots, samples of his socks to be sent to Portland Down for analysis.
We’ve taken a delivery of wood for the fuselage. After discussing with the supplier ‘OneByOne.co.uk’ Cyparis has been selected in lieu of Spruce. This wood is much more uniform and has an amazing ability to bend without breaking. Samples were left by the supplier, we all had a go at bending it and amazingly there were no breakages or injuries.
Glue has been ordered for the fuselage. ‘Titebond’. Gallons of the stuff, Mat claimed he got a good deal. If anybody wants a bath in glue please let me know.
Build Next steps
Even with the build space limitations the main surfaces are going together very well and a few more sessions should see them completed.
We have the wood for the main fuselage members but need to decide if we’re going to fabricate or laser cut the support gussets, either way we should aim to commence build by end of month.
We also need to sort the shopping list for completing the control surfaces, but again we should be good to go within next week or two.
Due to the nature of the main surfaces (and the speed of assembly) we’ve been able to progress as fast as we can with a limited number of volunteers. But now we’re coming to the ‘fiddly bits’ (technical term), so more volunteers needed! Interested?
Dave, Alan and Tom have been progressing the Technology demonstration activities. As mentioned before, to bridge the 100 year technology gap, Blackburn Flyers are including the 21st century electronics fit with GPS, MEMS (Micro Electro Mechanical Systems ) Gyroscope, Data-link, 3D video telemetry, etc.
Support offered by DSTL (the research arm of MOD) and Dassault Aviation in France.
The Industrial Avionics Working Group (IAWG) are supporting the software development with permission to reuse the software developed on the ECOA research programme (European Component Orientated Architecture – software architecture research programme conducted by the French and UK ). The IAWG members include:
- General Dynamics
- GE Aviation Systems
- Agusta Westland
- Selex ES
Design Concepts – Physical
This picture shows the main components of the on-board “Avionic” System.
The Main processing element is a Raspberry Pi Model A+ equipped with an ARM microprocessor as part of the System-On-Chip (SOC) with the system memory mounted on top.
The Camera is a High Definition (1920×1080) Pi specific model with dedicated hardware within the SOC enabling real-time H264/MP4 compression.
The GPS unit selected uses both the US (Navstar) and Russian (Glonass) satellite constellations giving high accuracy and rapid acquisition times. It also offers multiple interfaces and we have chosen the i2c (Inter-Integrated Circuit) bus – originally used with equipment such as televisions.
The MEMS Inertial Sensor Pack selected comprises a 3 axis gyroscope device, a 3 axis linear accelerometer and a 3 axis magnetometer (enabling derivation of Magnetic Heading). On the same board is an ATmega328 processor (the same processor as found in certain Arduino development boards) and with reference software can provide processed Heading, Pitch and Roll over a serial link – removing the need for further processing and sensor management on the Pi.
The Current proposed equipment list comprises 3 pi’s 2 cameras 2 GPS units and 2 MEMS Inertial Sensor Packs with the cameras and sensors being split between the 3 pi’s for redundancy and potential flight data enhancement.
Design Concepts – Logical and Enhancements
This view of the system shows “where” we could add the framework that allows software “components” to be added. This approach allows new features to be added without significant change to the existing software element. The network connection permits interaction with ground based elements.
Prototyping and Testing
The first item tested was the MEMS Inertial Sensor Pack to assess the performance of the reference software.
The two pictures show that the device is correctly sensing its position and transmitting it to the receiver – in this case a PC that is showing the values received as a graphic.
The second test performed was to assess the capability of the Pi to record video simultaneously with recording both the GPS and MEMS. An adapter board was assembled to enable direct mounting of the GPS and MEMS modules and allowing access for the Video and GPS Antenna cables.
The system was configured for automatic recording and for testing purposes, automatic safe shutdown, removing the need for a dedicated shutdown switch. This setup was then driven with the camera looking through the rear window. No anomalies were observed in the video and all expected GPS/MEMS data was recorded. The recorded track – green -is shown below with captures from the video
(Yes, that is Scotland and no, the shadows were not photo-shopped on later – Click on photo to enlarge)
Technology Demonstration Next Steps
The next activities associated with the technology elements are the design and implementation of the equipment mounting/packaging and power supply solution ensuring appropriate protection for the devices and catering for the specific mounting needs of the camera, MEMS sensors and GPS antenna.
In addition, investigation into and testing of possible radio technologies for the datalinks is expected to commen