Two Flying Wings

We had two flying wings in the air at the same time this week, which is fairly unusual. If a certain Zeno wasn’t on holiday then we might have got three. I was on the bike this week, so, in addition to my own design flying wing which fits in my backpack, the second wing was the Horizon Opterra. With a 2 metre span it looked huge.

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That’s my wing transit system. The wing is in the Head rucksack, while my Futaba Field Force 8 is in the camera bag on the handlebars.

This is the scene part way through construction, when I’m starting to think about how the Multiplex Zeno just clips together and how cold it is when the sun goes in.

You can just see the box for the Opterra in the background as we’re both building our wings. The Opterra looks really well designed internally and reminds me of a full size aircraft’s cargo bay when its top is removed.

At this point I had already flown somebody else’s Horizon UMX Carbon Cub, which had a huge amount of down trim dialled in straight from the launch. It was probably a good thing that the owner gave it to me to test as he was going to fly it himself if I hadn’t arrived on the bike at that point. All I can think is that, on the previous flight, somebody had tried to trim it to fly with the flaps (yes, it’s only 90g and it has ailerons, rudder, elevator and flaps). These were assigned to a switch on the top left, so, after gaining some height, I flipped the switch. This caused a big nose up moment, which resulted in a partial stall and wing over. I’m thinking that maybe, somebody trimmed this out by mixing the elevator/flap compensation, but didn’t do it correctly and applied it to the main flight mode? The elevator trim was right up the top to start out, but I finished with it just about neutral. It made things interesting for a while, but not as interesting as my initial launch with my wing.

We all watched the first flight of the Opterra after that, but, once it’s in the air, it flies beautifully. Mind you, it does have a fairly advanced computer stabilisation system. My wing only has two micro servos connected to a FrSky D4R, so the stabilisation system is in my brain. The Opterra is just huge when it’s doing low passes.

So then we come to my first flight of the day with my flying wing. I did at least two complete 360 degree left elevon rolls straight out of my hand before managing to hit the ground flat with power off. It was really very impressive, but quite a high adrenaline launch technique. I wish I had some sort of data logger so that I could play back what I actually did with the sticks because I’m on automatic at that point. In your mind you go through, “oh, it’s rolling left… a lot… and my hand isn’t on the stick as it’s just hurled the thing forwards so I can’t catch it in time… power’s taking it up and away from the ground, but that was a complete 360 roll… but now I’ve grabbed the stick”. I think I modulated the power to keep it going up (i.e. power down when the nose goes down as the roll is more like a snap roll and the nose is making a cone shape), then caught the roll with full right, but hit the ground as there was no forward momentum, it pancaked, but upright and flat and with the power off.

The only damage seemed to be a slightly bent motor shaft where it hit the grass at a downward angle. I wanted to know what went wrong, so, after checking that everything was really all right and moving the spinner cone forward, I launched again. This time I put in a lot of right aileron trim in preparation, but ended up taking it all out. I didn’t think it was flying quite right, but maybe I was just being super-sensitive because of the first flight, plus it was a bit blustery and this aircraft never did fly in a straight line? I don’t know, but I had a fairly decent flight, even if the landing wasn’t my best. This aircraft catches you out as the ground comes up much sooner than you expect. You have to get into the ground effect, stop it getting sucked into the ground with a lot of elevator, and don’t bleed the speed off too soon.

On the second flight with the wing, it occurred to me what might have gone wrong with the previous flight. I’m using the new LiPos which I flew in my RS352 two weeks ago. In that aircraft, I remarked that the power difference between these new LiPos and the one year old ones was frightening. They have loads more power. Now, I’d just put one of these into the wing, so I probably had a lot more power and the roll was a combination of torque effect and bad launching. The second flight went without incident and I was able to fly around with the Opterra for a bit before making an absolutely perfect landing. This was the best I’ve ever done with this wing.

The analysis of the LiPos when I got home was interesting, as both LiPos were still 70% full, meaning I got two 11 minute flights out of 30% of the capacity.

Finally, we also had a father and son, each with small drones, and a little 8 week old flyer who said he would come over with a Mavic next week, or at least his dad did.

And, here’s an update on the Atom. The blades are finished, but need a bit of balancing, so it’s almost there. The silver and metallic blue look really good together with the white.

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