A1-D: it flies!!! (with video)
After going through all the final assembly steps, I had to balance and tune the Juliet2 for its first flight. Thanks to the last minute changes in the internal weights distribuition, it centered spot on in the expected range, even though I had to position the battery as forward as the fuselage allowed (which means all the way up to the firewall). Bind the new FrSky RX-6R to our Taranis X9D plus was easy and finally we could see the plane “alive”.
Setting the radio for the Juliet2 First Flight
Compared to the original Juliet, the A1D has huge control surfaces. Therefore getting the right setup for the maiden flight becomes crucial. Not wanting to be surprised by excessive control sensitivity, leading to an upset, but not keen to numbing it down to much either, with the risk of running out of control authority in a critical phase of flight, I opted for slightly reduced servo throws with large amount of exponential to soften the response. I reduced the range of ailerons and elevator between 70-80%, and at the same time I set an exponential of around 55%. This way the plane is much less sensitive around the center position of the sticks, but there’s a lot of deflection available towards the end of the sticks travel if required. Of course theese setting are just a starting point, after the Juliet2 first flight there will be the chance to fine tune them.
Ground testing everything
Everytime I do some updates or repair to my models, I try to test them as much as possible while in the safety of the garage. There are a lot of things which can go wrong on little, delicate models like these. Before the Juliet2 first flight, I wanted to be sure that all the servos were working as expected, that the new ESC and motor were not overheating and that there weren’t issues wth the new receiver or its telemetry sensor.
Like I did with the Tundra a few months ago, the A1-D went through a series of ground tests before being “signed off” for the maiden flight. These included low-power taxi trials (plenty of walls in an underground parking), and a long motor run-up at various power settings with the plane tied to an heavy object.
For these garage test I generally use a couple of old batteries that I don’t trust anymore for the flights. Eventually I also tested the good batteries, to be sure about the connections and safety of the installation.
Just for the Juliet2 first flight, I added a couple of metal washers as ballast to move the center of gravity slightly forward.
Its a first flight, not a first date
Generally speaking the plane was finished at this point, but there were still several hours of work to really complete the project as I intended. For the most part, this meant I left behind cosmetic upgrades such as stickers and polishing the painted parts, but even some functional elements like the flap mix on the ailerons, the wheel pants or the whole lights system. Although the first flight of the Juliet2 was an important milestone of its development, the project is far from complete. Even considering this prototype construction alone, there are a lot of parts to be tested, adjusted or replaced. This of course after the flight testing will give us the necessary informations on were we are with the performance.
As an additional point, approach a maiden flight before investing hours to get a perfect look on the plane helps alleviating the pressure a little bit.
As all the family was there for the event, the first accomplishment of the day has been for sure squeezing two adults, a baby car seat, a golden retriever and two planes plus equipment in a sedan. To break the ice I started by flying the Tundra in its “Tundra-cam” configuration. I believe it’s important to fly a trusty , easy model before the maiden, as it starts the day with a positive confidence boost and you get a feeling of the conditions at the field. It then came the turn of the Juliet2.
And, finally, the Juliet2 first flight
After another couple of taxi tests, i felt I really had no excuses to delay the big moment any further, and I just went for it. As you can see in the videos, there was no problem whatsoever, without even going full throttle, the acceleration was impressive and the plane was in the air in a few meters without any bad tendencies. Before trying any fancy stuff, I started to trim everything. With my surprise, only the ailerons needed a little adjustement, and it caused sort of a drama as I unexpectedely found myself with an inverted trim switch (absolutely due to me being a novice with the taranis). Once that was sorted out, I was able to have a taste of the manevrability of this little hot-rod. I have to say the roll rate is quite extreme, at the same time it flies on rails and it can go pretty fast pretty quick when you push it.
As you can see in the second video, I carried extra speed on the final approach just to be safe, and ended up taking all the runway. It was a bit too windy to explore the rest of the flight envelope so I just kept flying the Tundra-cam for the rest of the afternoon.
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Other posts about Radio-controlled planes:
It has come the moment to look forward. Unfortunately this also means we need to make space for the next projects, and say goodbye to A1-C. We are not going to ruin the surprise about what will be next here, and besides, this post is just to celebrate the end of the Juliet’s flying days.