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...

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...

Fun With the FT Viggen.

...fast and fun

The Viggen has proved to be a great addition to the fleet, being fast stable and distinctive in the air. And, all this despite it being my first Flitetest build.

Most amazingly is how easily, and stably, it launches; being flat underneath you have to launch it underhand and yet it climbs stably without threat of stall or spin.

It's benign characteristics are a combination of it being a delta, but also certainly due to the calming effect of the canards, keeping the nose up and reducing the load on the wings.

You can turn the Viggen as sharply as you like and it won't do anything nasty. In fact, so effectively will it turn that it's almost like it has vectored thrust, being able to keep on looping almost about its own length.

And it's quite quick too; my version runs a common-or-garden ebay fan with a 50A ESC and is good for about 100kph. You could load it up with a 12 blade fan although I'm not sure how much aero load you'd want to put on a foam board plane...

Flitetest Viggen. First Flight.

...no bites from the vegan

Preparing for the first flight of the FT Viggen I was both excited and nervous; it looked to be a great flying plane made a little more forgiving with the canards. However, having a completely flat underside, it was also the first plane that I’d ever have to launch underhand.

So, as I’ve done several times before, I headed into the depths of the paddocks to a launch spot with long grass, just in case I needed an arrestor bed. As it turns out not really but it didn’t hurt since, at my first attempt, the trajectory was too flat, and the Viggen simply disappeared gently into the foliage.

The second attempt was good, the Viggen holding an upward attitude till I could bump up the throttle and then it was on its way.

Flitetest Nutball. First Flight.

...a well rounded plane


Whilst waiting for parts to arrive for the completion of the Viggen, my first Flitetest project, I decided to do a Nutball from a spare sheet of foam and a scrap motor.

It's a very easy plane to make, much simpler than the relatively complex Viggen, so didn't take long to make at all.

However, I didn't like the front-mounted motor or externally attached battery, which I thought looked ugly, so I mounted the motor internally and made access to the power pod through the top of the plane.

The result was a much neater-looking plane however required a much bigger battery (a 1300 3S) in order to compensate for the relocated motor.

With a big wing area I didn't think this would be a problem, however it turned what should be a slow floater into an absolute handful of a plane. Additionally, the elevator/rudder setup seemed highly ineffective with the Nutball not wanting to turn much at all. In fact, overall, flying the Nutball it recalled my first flights with the nose-heavy Radjet. 

By the end of the second flight, which ended with the Nutball spiralling into the paddock, I'd decided to reduce weight with a smaller battery mounted on top, and to change to elevon mix layout to improve flight response...