It’s a flying day again, but I’ve got no transport, so it has to be the bike and the flying wing this week. This is what I love about flying radio controlled aircraft. I can take a 10 year old balsa flying wing model with 2 servos and a speed controller, sling it on my back and cycle over to the flying field. It’s just a lot of fun flying something that I designed specifically to break down into a ruck-sack to be portable. Since I added the motor about a year ago, I can share the batteries that normally power my RS352. I had 5 of them all charged up this morning, but only flew 3 in the end as my nerves couldn’t take any more. It’s not exactly an easy model to fly, but it is a lot of fun. I also had the idea of taking the HubSan X4 with the camera and trying to take flying shots of the wing on the ground, but it turned out to be a lot harder than I expected.
When I arrived this morning it was bright, sunny and cold with a 10 mph wind that made for some very challenging conditions. We were standing there after one flight and I said, “did I just land the wrong way?” as the wind was in the opposite direction. Then in about a minute the wind swung through 180 degrees again, which summed up the entire morning really.
To start with, there was a guy with a big yellow Cub flying around, plus my friend with the tiny Champ who I haven’t seen for ages. He had a new electric bike, which seems like a good idea to me as I could hardly stand after my cycle ride up the big hills. I flew his Champ for him and he had a go, but when the power cut I lost control completely and got very close to a tree before it landed safely. It was flying away from me against the wind, I tried to turn to bring it back and nothing happened. I don’t know how much I was actually able to influence the aircraft after that, but I managed to get it cross wind and pointing slightly back towards myself. I figured it was never far enough across the field to actually hit the tree because it is so small, but it’s always difficult to judge. It was a good 50m away when it touched down in some long grass, thankfully without any damage. On inspection, none of the controls were working, which we attributed to the battery dying completely. It doesn’t normally do this as the power should drop away when the ESC cuts, leaving you with full control. Anyway, no damage was done.
My next flight was with the HubSan X4, after putting the flying wing together. The idea was to film the wing sitting on the ground using the camera equipped HubSan. This is easier said than done and I’m going to have to do some editing of the videos as they show the HubSan being thrown all over the place in the wind. I had to use the expert settings to have enough control to fight the wind, but the problem was that once I tried to point the camera in the direction I wanted to film, it got caught by the wind and thrown around. At this point the guy with the E-Flite Advance arrived and I was just about ready to launch the wing.
I don’t know whether it was the turbulent conditions, but you could see the wing oscillating left to right in yaw as it was screaming around in the wind. Adding power during flight sees it torque roll and yaw, so you have to handle the throttle very gently. I’m also losing a lot of height in the turns, not being able to pull the nose around and hold it up on the elevator. The launch now sees it climb vertically upwards, which I have to check with the elevator and back the throttle off. It does this on anything over about 75% power which is quite interesting. The prop isn’t folding back, which means the glide is like a brick. An obvious answer is that the brake isn’t programmed as I took the ESC and motor out of my CAP231, which is an aerobatic plane with a fixed prop. I’ll have a look into this later, as I’m sure it would glide really well without the big airbrake. Speaking of airbrakes, landing is interesting. It’s impossible to scrub off enough speed and I always end up having to drag it along the ground to slow down. In fact the third flight turned into a touch and go as it still had enough speed to lift off after a 3m drag along the ground. This actually worked quite well, but I don’t think I could repeat it. The problem is that as the speed comes off, the aircraft becomes less and less controllable as the elevator ends up working like a speed brake and it hits a point where it just tip stalls into the ground. So the landing technique is to come in low and fast and run it along the ground. It might actually be worth adding a strake on the bottom to act as a drag brake, something like the ME163 Komet had. Or I could just fix the aerodynamics so it’s controllable at low speeds. Anyway, I managed to get in three flights of around 5 minutes each and the post flight analysis is showing all three packs at between 60-70% full, so it’s not using that much power.
Part way through my flights with the wing another guy with a small profile plane turned up and I managed to film him flying and doing 3D aerobatics with my HubSan’s camera (just). In the end I stayed about half an hour longer than usual and was just in the process of leaving when three people with racing quads turned up. I left them to it at that point as I knew I had to cycle back up the big hill.
That’s it for now, but I’ve got a time-lapse of how to add blade guards to a HubSan X4 to edit, the flying videos to edit and an AutoGryo to build. I’ve just made the pilot’s head which isn’t looking too bad, so it’s starting to come together.