Kossel XL Firmware Fixes (fpos_t' after 'struct' and MANUAL_Z_HOME_POS)

...critical fixes for your Kossel XL 3D Printer



Runtime error fpos_t' after 'struct' 


Rename fpos_t variables in SdBaseFile.h and SdBaseFile.cpp to another name like fpos_t1.

C++ won't let you use typedef and struct for the same variable name. Thanks to webliya.

Can't Update MANUAL_Z_HOME_POS



The EEPROM on the Arduino Mega controller stores configuration values.

Sometimes these values override updates you make to Configuration.h. 

Deactivating mine solved this issue instantly, like this:

In Configuration.h.find the // EEPROM section, then change the following lines into comments (add // in front):

//#define EEPROM_SETTINGS

//#define EEPROM_CHITCHAT


Upload to Arduino Mega using Marlin, then home your Kossel XL (G28 command).

Your revised Z value should show in the LCD display. Thanks to zennmaster.

Did the Sketch Upload to Arduino?



Connect Pronterface to your 3D printer.

Check the side status bar - the top line shows date and time the sketch was compiled. Happy days !

FT 3D. First Flight.

...got there in the end

As soon as I saw the video of the FT 3D I decided I was going to have to make one. The build was reasonably simple and the product looked great; a pert-looking aircraft with blacked-out canopy and bristling with vortex generators and wingtip plates.

So it was with much anticipation, and nervousness as usual, that I got around to its maiden flight. My first mistake was the rates weren’t turned down enough, and the expo needed to be much higher. I was lucky to recover control before it speared into the meadow and brought it round to land so I could reprogram the Taranis.

Second mistake is it didn’t really glide - I cut power expecting to ease it in for a landing, but instead it stalled and plummeted down, buckling the undercarriage and breaking the motor mount.

Taking it home for a re-think, I installed a smaller prop than the very solid unit which was one of my Trainstar spares and also cut off the back half of the swappable power tray which was doing nothing. Importantly, I also covered the underside of the cowling with poster board in the hope the shape would support the nose which had been dropping severely on the first flight.

So, back to the field again to test the results, which happily showed significant improvement. Except, unfortunately, that this revealed another problem - the ESC overheated despite the NACA duct cut right in front of it, causing the FT 3D to once again plummet down for a repeat end to the flight.

Take 3, now with a NACA scoop - an inverted NACA duct service as a very large scoop to keep the ESC’s delicate constitution cool. And this time everything seemed to work - the #D was light & floaty enough, easier to control and seemed happy to be flying. All good, now time to learn how to fly 3D properly…

FT Baby Blender. Re Maiden !!

...a super bipe

I had long wanted a bi-plane and, having been bitten by the Flitetest bug, I decided that the Baby Blender would be the one for me.

Having built it and checked the CG I discovered, as I have with a few FT planes, that it was tail heavy and therefore I decided to fly it with a 2200 battery to add weight to the nose.

In addition to now being heavier, for the first time I used an "all-in-one" pack from eBay which, at about the same cost as making the plane, I thought a perfect fit. Unfortunately the Baby Blender turnout out to be pitch sensitive, either going up or down in a hurry with no happy medium achievable.

Also unfortunately, the eBay motor popped after only a few minutes, leaving the overweight bipe to plummet earthwards.

Fast-forwarding several months, I eventually replaced the Blender's motor and also gave it a covered lower cowling, something I'd tested with success on the FT 3D. Also, I decided to go with a lighter 1800 battery and see what happened.

The combination turned out to be a winner, the lighter-weight FT was still stable and now with a much lighter nose it quietly floated around the field once I'd set the elevator trim down a little; it headed for the skies so much lift was it generating!

The only change I made from the first flight was to increase the aileron throws a touch. Apart from that all good, and I'm looking forward to many more flights peacefully punting the little bipe around the oval...

Rarebear Funfighter. First Flight.

back in business...

The Rarebear was my second fast plane, after the notoriously hard to launch Radjet. Despite its diminutive caricature proportions, it was blindingly fast and flew on rails. However, as happens, it had it’s share of incidents, including a near lipo fire and a high speed excursion through a barbed wire fence. Finally, battered and weakened beyond stable flight, it was retired to the wall and gradually stripped of it’s internals for new projects.

So it was with great excitement that I came again to consider another Rarebear to join the flying corp. The first time round I’d chosen the PNF version, in the rather dull white and brown livery, but this time I got the ARF kit, unpainted and without decals. This time also I changed the battery; last time I went with the “ballistic upgrade” 45-90C which, when combined with the diminutive current-junkie funfighter motor, makes for epic speed and addictive noise. However it was far too fast in reality, so this time I chose the same 850mAh 4S battery, but in more sedate 25-50C form.

Also, I had a bit of fun rendering the Rarebear into its donor Bearcat regalia; Navy decals with pacific blue paint (a few shades lighter than the real thing). Overall I thought it looked great. Also, importantly, I applied tape to all the hinge lines (excluding the rudder which doesn’t function) to avoid a repeat of the “missing bits” episode of the original.

So to the first flight. Yes, I was nervous. The Rarebear is small, fast and can kick on launch, so certainly not to be taken lightly. So it was with some trepidation that I threw it up on about half throttle and held my breath.

As it turns out, the rare bear was very well behaved, climbing sweetly into the sky; a little steeply because I’d set the elevator up a bit and, after it had levelled off, flew absolutely beautifully, straight and stable, turning with characteristic crispness and climbing with absolute disregard for gravitational dynamics.

In all, the first flight was excellent, the little ‘bear even slowing up for landing without a hint of wing drop, so I’m now looking forward eagerly to pushing the limits towards full throttle, enjoying the subdued howl of the little fighter across the kangaroo paddocks…

FT Cruiser X-57. First Flight.

...hey I made an X-plane. sort of...

Having seen NASA's intriguing X-57 Electric Research Plane, I decided to converted Flitetest's twin-engined FT Cruiser into an RC version of NASA's experimental plane, featuring twin electric motors mounted in the wingtips.

The X-57 actually features 14 motors, twelve small motors with folding props mounted in the leading edge of the wings providing supplementary power for takeoff. The two larger motors installed in the wingtips provide the high-speed cruise propulsion.

I wasn't going to be wiring up fourteen motors, so I dispatched with the dozen leading edge units favouring the simpler hand-launch solution. I used small 89W quad motors (1806 2300kv) running at on a 3S 2200 battery. The propellors are 5x3 props, swinging inwards sweeping air onto the top of the wing to counteracting the wingtip vortex.

This is one of the main benefits of the wingtip design, a second being that the concentrated wingtip flow feeds into the propellor, increasing the dynamic thrust. Finally, additional thrust is generated by virtue of the outside sweep of the prop being unimpeded by the presence of a wing; the prop wash goes into free air.

The modified FT Cruiser with weighs 940g all up, or 749g without battery compared to the spec mass of 766g. The 17g difference is due to reduced wing size, one less servo (rudder servo ditched in favour of differential thrust) and smaller motors. However, 7g ballast had to be added to the nose for CoG correction due to the motors being set rearwards compared to the standard Cruiser configuration.

The motors generate a combined 710g of thrust as installed, sufficient for cruise but certainly not 3D flight. Static thrust of a commercial aircraft is a quarter of its loaded weight and around half of its empty weight. In the case of the xCruiser this would equate to 235g to 470g respectively. So it's comfortably powered in aircraft terms although less so in RC terms where closer to 100% is nice-to-have...

Turbo Porter Sunset

...evening walk became an evening flight

Wild rainy weather for the day suddenly subsided into a golden sunset, warm rays flooding under the dissipating sheet of clouds. Taking the opportunity for some exercise, I headed out for a walk. However I hadn't made it to the corner before I'd decided that this would actually be a great time for a sunset flight.

I don't often fly at the local fields anymore as there's not that much space, quite a few trees and often people walking dogs or playing. However, with sunset approaching and it having just stopped raining, I packed the Turbo Porter and headed down the road.

As ever sunset changes rapidly and the best of it was gone by the time the Porter headed to the skies. However, I managed to capture some of the fading sunset and enjoyed compiling the video... 

Canadair on the Duckpond

...finally flying off the pond

The field where I often fly was prone to flooding at the southern end; an event which occasioned the influx of birds of all kinds and the occasional kangaroo something for a splash.

However, unfortunately the sports club didn't share my enthusiasm at an inundated playing field and so instituted an engineered solution to pump the flood waters away. Happily, after a year or so, this fiendish system has failed, heralding a triumphant return of the ephemeral pond.

I had often been tempted to get something flying off the pond but for some reason never got around to it. However, for once, I managed to get to the field with a float plane while the pond was still full and when the weather was OK, in this case with the Canadair.

Unfortunately, as far as the video was concerned, the sun dipped away behind the clouds just as I the Canadair hit the water, so the video quality was frustratingly compromised. Despite that technical hiccup, the flying was a success, making the wait worthwhile...