Low cloud stops play

Yesterday was spent at the Mynd without any flying. The forecast looked reasonable but low cloud surrounded the Long Mynd all day and stopped flying. The drive up to the club and the views across to Stiperstones were great with the low cloud surrounding the hill.

Stiperstones, Norbury hill and Heath Mynd from the back of the clubhouse.

Stiperstones, Norbury hill and Heath Mynd from the back of the clubhouse.

A couple of times the east wind picked up and lifted the cloud out of the valley and covered the airfield in just a couple of minutes. You wouldn’t want to be airbourne during that! I learnt plenty talking to the various members and so the day wasn’t a waste despite the non-flying conditions. I also had a quick demo the retrieve winch operations just before a ultra low cable break drill was cancelled due the cloud conditions.

The club acquired a new Schleiker ASK 13 and this arrived in the late afternoon so I spent a couple of hours rigging that before heading home, it looks like a nice bit of kit and hopefully I’ll get some time in it in the coming months.

I also managed a couple of quick test flights of the latest iteration of my mini mini flying wing. It’s fast as hell and fun to fly. I think it’s nearly there but needs greater pitch authority as I can’t get it to stall and landings are far too fast as a result.

Mini wing version 4

Mini wing version 4

A full day at Midland Gliding Club

On Sunday I spent a full day at MGC. I flew six flights in the club’s ASK 13 ranging from three to eight minutes in length. The flights were short due to low winds and thermal activity. I flew with MGC’s instructor Mark S. and flew the second and third parts of a winch launch, tight turns, stalls, a few landings (assisted quite heavily by Mark).

Playing around with model aircraft, flight sims and the little light aircraft flying seemed to help me pick things up quickly and Mark remarked on this. I have a couple of bad habits that need resolving. I tend to drop the nose in longer turns and gain unwanted speed and in the information overload of landing I for some reason get aileron and rudder coordination out of whack. I expect that the coordination issue will resolved as I get more comfortable with landing and have more time in the air and I’m going to have to make a conscious effort to maintain pitch and speed in longer turns.

The drive up the Long Mynd on Sunday morning

 

In all it was a really enjoyable day and I realised why I’ve been yearning to get into the air again! The day finished with an “instructor flight” in the club’s ASK 21, two tight loops followed by a couple of chandelle and a low pass of the field, I forgot just how fun aerobatics were!

Here’s my XCSoar log files visualised in Doarama

A new blunt nose versa wing

After losing my last versa wing into the River Wharfe when flying under a bridge (Don’t ask) I’ve decided to get another built. The plan is to build without a motor for some slope soaring fun (which I’ve never tried before) and then to add a motor and some FPV gear as time allows.

The parts have all arrived so I’m ready to get started.

Here is a video of me bashing the last versa wing around my home field in Wetherby in early 2015. At the start of the video you can see the bridge that caused the loss of video reception and the aircraft. That was a sad day.

A first flight at Midland Gliding Club

I’ve been looking into starting flying a lot recently. When I was 13 to 15 I was in Air Cadets and flew a few times in the Chipmunk trainers at RAF Woodvale. After weighing up small powered aircraft, paragliding, hang gliding, ultralights and gliders for a long while gliding seemed to have the best balance of fun/safety/cost.

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FlightTest Blunt Nose Versa

I’ve built a blunt nose versa using the flitetest PDF plans. British foam board is almost twice the weight of the stuff available in the US so my set up has more power to compensate and probably doesn’t glide as well, fast landings are in order too.

The aircraft flies really nicely and even in a forced stall won’t drop a wing!

Naze32 configuration via Bluetooth Android and Cleanflight

250 Mini quad with Naze32 bluetooth transceiver attached

I recently added a bluetooth transceiver to my 250 mini quad. Travis Grindal’s video shows how simple it is to get working. It makes configuration at the field much quicker and easier.

A couple of things to note. The bluetooth module that I bought is different to the standard and the connection PIN is “3232” which took a while to work out. Secondly, it is possible to connect to the Naze32 board via the cleanflight configurator on a computer. Just make sure that correct port and baud rate are selected as shown in the image below.

Cleanflight configurator bluetooth settings

Here is Travis’ video walking through the bluetooth set up.

 

Georeferencing ImageJ output files with GDAL

I’ve been using ImageJ (aka FIJI) to create an NDVI floating point image from some aerial imagery of a heathland in Nidderdale. In order to import the NDVI output image into a GIS package or image processing software like eCognition the NDVI TIFF needs to be georeferenced.

The original aerial imagery from which the NDVI image was created has already been georeferenced so we can grab the coordinates of it’s corners and copy them over to the new NDVI GeoTIFF. The steps below go through this process.

  1. First install gdal. If you are using homebrew on a mac, the install process is as simple as
    brew install gdal
  2. Get the CRS and coordinate information from the already georeferenced GeoTIFF with the gdalinfo command
    gdalinfo sourceimage

    GDAL info
    The values we want from here are the GEOGCS (WGS84) image size (7428, 7932) upper left and lower right coordinates.

  3. Now we can take those values and create a GeoTIFF from the NDVI TIFF image with the following command
    gdal_translate -of GTiff -a_srs WGS84 -a_ullr -1.6811175 54.0748652 -1.6754438 54.0713020 GeoTiff\ ndvi-input-image.tif ndvi-georeferenced-geotiff.tif

    You will see a status bar as below as the image is tagged by GDAL.

    gdal_translate GEoTiff Tag

  4. Now we can import the NDVI GeoTIFF image into whatever GIS or image processing software we want. Below you can see the georeferenced NDVI GeoTIFF perfectly overlaid on the NGB aerial image that the georeferencing information was taken from. The GIS software in use here is QGIS.
    GeoTIFF NDVI image in QGIS
  5. Now we can go ahead and use the NDVI image to aid in vegetation classification and we can export classified objects as georeferenced *.shp files and use them in our GIS software

    Heathland classification eCognition shape file export

    eCognition shape files exported to QGIS. Credit to Letters from Sal for the how-to.

Banggood.com LEDs for orientation

Banggood.com strip LEDs for drones and multirotors

Banggood.com strip LEDs for drones and multirotors

I’ve been looking at various options for adding orientation lighting to my hexacopter. It’s a toss up between price, visibility and power draw. I finally settled on these banggood.com strip LEDs and I’m impressed. They’re nice and bright and will help me to keep orientation when flying the hexacopter at a distance. I just wish delivery was a little quicker. It took about 3 weeks for these to turn up.

They are pretty cheap too at £1.62 per strip with free shipping. You can pick them up here http://www.banggood.com/LED-Decoration-Board-Strip-3S-For-QAV250-Quadcopter-p-951108.html

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Replacing the voltage regulator on an APM board

Fixing the APM voltage regulator
Fixing the APM voltage regulator

Fixing the APM voltage regulator

I recently had a problem with my APM arducopter board. I accidentally blew the 3.3v voltage regulator. I suspect that I damaged it whilst connecting the board to USB power whilst having a camera gimbal attached to the ‘copter. This may have resulted in a high current draw through the receiver and APM board blowing the voltage regulator.

After damaging the regulator I was getting all sorts of strange errors from the board. The gyro, compass, GPS and barometer were all giving me errors due to the fact that they were now getting 5v instead of the needed 3.3v.

I spent 30 minutes with a soldering iron and a new voltage regulator and got the APM board back up and running. I made a short video of how to replace and fix the voltage regulator on the APM board.

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