gke's blog - RC Groups
gke's blog View Details
Posted by gke | Jun 04, 2017 @ 04:47 AM | 3,224 Views
Intended to be used as a fixed wing test platform for UAVXArm.

Bought on sale as a kit from Banggood but in hindsight could have bought a foam only kit for even less as I have plenty of carbon tubing .

Used PVA for assembly but left wings unglued to make it a bit more portable. PVA tends to crack on high-speed crashes rather than tearing up the foam. PVA also tends to foam but can be contained using masking tape until it dries. Wings are fastened using woven fibreglass tape which lasts 1-2 seasons in our sunshine. In this case the tape has been fastened on the underside. Winglets are fastened using hot glue. Control horns are epoxied to the carbon rod in the elevons using a slightly oversized hole in the foam.

Motor is an AXN-2208-2150 which comes originally from an AXN Cloud and runs a 6x4.5" prop used on some of my multicopters. Current is around 19A and I am using a 30A Turnigy Plush ESC. Servos are HXT900 9gm and while I would have preferred MG one of the last two I had was DOA.

I am using a 1300 3s pack in the GoPro camera position which will give around 45min in still air with an AUW of 475gm. Predicted climb rate is around 9M/S. A 2200 3s pack fits in the main compartment but pushes the AUW to 560gm and only gives another 10 minutes of flight time. The VTX and camera roughly another 50gm.

CG set initially at 125mm as recommended but moved back to 135mm. This is just forward of the main spar currently but I will most likely go back to 140mm which is...Continue Reading
Posted by gke | Jan 25, 2017 @ 03:32 PM | 3,324 Views
There are lots of camera gimbals out there so this is directed to people who have older gimbals compatible with the BruGi gimbal controller software. The gimbal I bought a year or so back was throwaway cheap but had closed source code installed. I elected to use BruGi, the development of which stopped around 2014, and to add temperature compensation for the gyros.

My version which carries with it the usual GNU "all care and no responsibility" is here:


The original code is here:

Posted by gke | Jan 02, 2017 @ 12:10 AM | 4,135 Views
Time to build a plank with a bit of "Wick" so this is a build of the 60" Zipper put with a PW51 airfoil . The Zipper was originally Birdworks way way back with an EH 2-10 airfoil but for more than a decade it has been available as a part kit from Off The Edge Sailplanes in Oz. Yes it is an old design but then not all new things are that good.


Mine will probably not be quite as pretty as that on the Edge page my first build being WBPU and a few layers of light glass cloth. I will add a thin strip of carbon plate as a spar to help out the somewhat thinner glass skin. Glenn aka "Zipper" offered to cut me a set of balsa elevons as well which I will sand to profile if required as I will see if the WBPU covered elevons prove stiff enough. I will most likely commit sacrilege and add a motor . Sort of functioning ballast.

There are a number of build threads out there and the outline instructions are on the Edge pages:

Posted by gke | Dec 27, 2016 @ 04:41 AM | 3,222 Views
Some time ago I did a quick wiki on how to apply firmware updates to earlier FrSky receivers specifically allowing the D8R to output serial or CPPM. This wiki became lost when Google dropped their support for projects but may be found here:


The original link was:


This will redirect you to my gitHub page but the link does not resolve to the actual wiki.
Posted by gke | Oct 31, 2016 @ 04:45 PM | 3,536 Views
I have a Dream Flight Weasel which has not had much flying mainly because the slope winds are not always kind.


This proved to be the case recently and Ray mused "I wonder what it would take to add a motor?". He has a Weasel as well but he knew I would immediately take the plunge .

So I did a quick mod and added a BE1806-2300 with a plastic 5x3 prop borrowed from my 250 Racer spares along with a Turnigy 12A ESC and 1000mAH pack. The weight has increased by a shocking 15gm . Others, of course, have also done similar conversions if you search them down.

The static thrust of the motor/prop combination is 390gm just slightly above the AUW of 380gm so vertical is possible. Pack is good for around 15 minutes at full throttle and an hour at cruise. Air to the ESC behind the battery could be improved by removing top hatch or putting a tunnel through to the launch finger hole?

The changes to the fuselage are straightforward with the removal of the rear wall of the original battery box and a ply firewall braced backwards with triangular ply doublers - the foam is too squishy.

I could have just cut the nose off and end glued the firewall but I wanted to preserve the lines reasonably well. I used WeldBond white glue which takes a while to dry but is slightly flexible and adheres to the foam quite well.

Test flight confirms performance and certainly easily vertical. Two longish flights and only 270mAH from the pack. A rather bleak damp day but caught some thermals as well - surprising .
Posted by gke | Apr 20, 2016 @ 08:05 PM | 5,731 Views
Commenced build of an Arado 555 based on that of Josef Poisinger's 1200mm version:


I have used an 8% Phönix airfoil instead of the original 12% to hopefully improve glide performance.

Build will be 3/4oz glass directly over foam cores using water based polyurethane (WBPU) which I have used before as a covering technique.

Propulsion will be either 2-4 EDFs or single propellor interchangeable on plug-in pylons.

Cores weigh 160gm bare without wing extensions which will be solid balsa - foam too hard to cut accurately. I am using lightweight filler to repair minor and one major (photos) hot wire cutting problems. The foam I am using sands well and I may put a light wash of filler over the wing.
Posted by gke | Mar 22, 2016 @ 01:13 AM | 6,079 Views
I have a larger Arado 555 build based on Josef Poisinger's 1200mm version underway but on a whim decided to build a mini version for indoors. It uses Josef's wing outline directly and is simply scaled 50% to a 600mm span.


First version used all of the electronics from a WLToys PoleCat (F939). The geared motor decided to hack into the wing at full power and so I replaced it with 2 Chaoli 7x20 motors running reversed Hubsan X4 props.


Notional thrust ~50gm with AUW of the aircraft, including 200mAh 1s battery and rather too much glue, is 54gm.


Foam is ColorBoard from Diaso. Elevons are inboard unlike Josef's elevons which are outboard, as they should be, but this proved to be too difficult/messy.

Video maiden flight outdoors at VARMS:

20160322 20160322 VARMS Arado 555 Mini (1 min 30 sec)

Indoor after a number of mods written up below.

20160420 Arado 555 Mini Flying Wing @ Waverley (1 min 6 sec)
...Continue Reading
Posted by gke | Sep 27, 2015 @ 06:23 AM | 5,854 Views
Flight control firmware for multicopters and fixed wing aircraft based hosted by an Arm32F4 with MPU6000, HMC5983 & MS5611 all SPI.

Posted by gke | Sep 21, 2015 @ 07:16 PM | 7,550 Views
Because it was reportedly impossible I have added RTH, or more correctly Turn To Home (TTH), to the last OpenPilot release 15.02.02 for CC & CC3D. Testing has been using EasyStar, Radian and Phantom Wing. It will probably work on multicopters as well.

The source modifications and firmware files are here:

Posted by gke | Jan 01, 2014 @ 06:18 PM | 9,111 Views
TxAdapter_gke is an open source standalone adapter translating CPPM signals where available from a transmitter, to Hubsan and FlySky signals.

Almost all of the adapter code was originally derived from the work of PhracturedBlue and others for the open source universal transmitter "Deviation". Inspiration for this development, which was intended for my own use, is due to Midelic.


Battery Monitoring

When used for the Hubsan X4 products flight battery voltages may be monitored with the throttle being progressively scaled back when a preset voltage is reached forcing a landing before the battery is destroyed. A buzzer may be added to give an audible warning.

MultiWii Telemetry

The Adapter produces MultiWii GUI compatible telemetry for attitude and battery voltage display. The only restriction is that for 8MHz processors the MultiWii GUI baud rate is limited to 56K.

Processor and Pin Assignments

The Adapter will work on most, if not all, Arduino compatible boards. It will also work on DIY Atmel based boards. Programming is by use of the Arduino development environment. Uploading programmes uses the processors UART, or where available USB, interface. A programmer is not required.

The default pin assignments are the same as those used by Midelic are detailed in the config.h file. Other parameters including unique ID, battery cutout voltage etc may also be changed in config.h.

Important Note that the resistive divider as pictured https://www.rcgroups.com/forums/show...9#post27180258 is incorrect. The divider should be wired to reduce the 5V PPM signal to 3.3V required by the Arduino. Thanks to guytzoler for noticing this.

Transceiver Module

The Adapter uses the A7105 transceiver. The maximum voltage on any of the A7105's pins is 3.3V and for this reason a 3.3V processor should be used.
Posted by gke | Sep 14, 2013 @ 02:22 AM | 7,483 Views
MWLite-gke is a radically cut-down version of MultiWii 2.2. It is targeted at flight control boards using the Atmel 32u4 processor and has support for brushed DC motors as well as regular brushless ESCs. The sensors supported are the MPU6050, HMC5883L, MS5611 and BMP085.

The latest version may be downloaded as a zip file from: