Month: April 2016

Virtual No Flying

I’ve been a bit busy with work this weekend and the weather is also quite windy, so I ended up cycling over to the flying field with nothing to fly. I was really late and didn’t arrive until about 11:30 and stayed until 12:30 hoping somebody else would turn up. In the end nobody did and I sat there playing PicaSim on my phone to amuse myself. It’s not the same as the real thing, but the weather was against it this week. I did notice, though, that the top of the flying board was missing which I don’t think was the case last week. That’s rather annoying, but we could really do with getting it fixed anyway.

The building of the autogyro is going quite well and I’ve got the radio in and the head working. I’m going to try and use an inclinometer to get all the movement angles right before cutting the pushrods to length as I don’t want to cut too much off. The pilot is glued in, so I need to figure out how to fix the canopy in place. For such a large hollow fuselage, it’s amazing how little space there is for the installation.

That’s it I’m afraid, back to work again now.

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Komet

Although it’s quite cold this morning, the weather is perfectly flyable again with bright sunshine and just a little wind. Actually, the wind changed back and forth through 180 degrees all morning which was interesting when landing and taking off. I also got to fly a UMX SpaceWalker and launch a foam Me163 Komet.

The drones didn’t make an appearance until much later in the morning, so we had a big yellow Fun Cub, EFlite Advance, Me163 Komet (straight from Hobby King), the UMX Spacewalker and a HubSan X4, two bungee launched gliders, plus my RS352. Part way through the morning a guy with a young kid arrived and they both flew what looked like one of those Syma quadcopters some way off from where we were. Then, just as we were leaving, somebody arrived with a DJI Phantom.

It’s not easy taking pictures of aircraft with a smart phone. I’m really going to have to get a proper camera with a lens, but you can just about see the Fun Cub against the blue sky and white fluffy clouds.

I flew the Spacewalker first, which has an enormous amount of dihedral for such a small light plane. Even with all that dihedral, though, it was still very unstable in the conditions. It wasn’t particularly windy, but it wasn’t flat clam and there seemed to be a lot of low level turbulence with the wind changing direction all the time. I ended up putting about 50% right trim in to keep it from rolling left, but the flight was over all too quickly. The battery gave up on me and I ended up landing in the long grass near some deer, who didn’t seem in the least bit bothered by either me or the plane.

After the Spacewalker, we tried to make the HubSan X4 work, but it seemed to be having the same problem as my old one used to. It would turn on and bind, but was completely unresponsive to the controls. After fiddling around with it for quite a while and trying the reset trick, we gave up. Then I had a flight with my RS352, after which I launched the Me163 Komet.

Although the Komet has a set of dolly wheels, it was never going to get off the ground from the rough grass, so the pilot chose to eject them before the first flight. This would be really brilliant to do in flight as it’s a scale representation of what the real ones did. They would take off using a dolly undercarriage which got left on the ground as the plane took to the air. The model uses a servo channel to drop the wheels off, but it did get a bit stuck on this occasion and the wheels had to be coaxed off by gentle shaking. Now, for an aircraft which has a long, flat, central fuselage underneath, it’s remarkably hard to get a good grip on it. Made from foam, the surface is quite slippery and in the end I elected to do a two handed throw holding the front just ahead of the wing and the flat bit at the back behind the wing. This is similar to the single handed throw I used to use with the low wing Tucano, allowing me to push through the aircraft to give it a decent launch speed. Holding the front gives me the ability to control the attitude and get a flat launch. This turned out to be a good decision because, as I was launching it, I could feel that the prop wasn’t biting into the airflow enough to produce decent thrust. I went longer on the launch, gave it a huge push from behind and it sailed into the air. After 10-15 metres it was on step and flying.

A quick glance a the pictures above and you would think that it was a commercial jet cruising at 10,000 feet, but look closely and you can see that it’s the Komet.

In the air it was very quick to roll, so the pilot used the 50% rates and it was still quick, but flying very nicely. Unfortunately, the first flight ended in a bit of an incident when he was rolling it to show how quick it was, got disorientated and pulled up into the ground when it was actually inverted. We all saw how hard it hit the ground at an angle between wing tip and nose. The foam construction must have absorbed the impact and saved it because there was no visible damage apart from the pitot tube coming off, a broken prop and stress marks along the wing and nose where the impact was. Very impressive.

Over the rest of the morning I managed another 3 flights with my RS352, but I’m still having problems with the pop adapter sliding off. I’ve been re-tightening it every flight, especially after the second flight where I managed some very good prop hanging. I cut the next flight short after that due to a sudden control problem which I still don’t understand. After doing loops, cuban 8s, stall turns and flick rolls, there was a sudden right aileron roll that I didn’t initiate, followed by what I felt was a very sluggish aileron response. It was in a good position to land so I did, but I can’t find anything wrong. In the air I was reminded of the time one of the aileron servos locked, but it must have just been the funny low level turbulence we had been experiencing all morning. I put the next battery in, climbed into the air and it was all normal, so a proper check of the aircraft is in order this evening.

That’s it for this week, except to say that I have made some progress with the ATOM AutoGyro and have the motor and speed controller installed. Now that it’s got power, I can connect up the radio and servos and see the head work for the first time. I’m going to try and make an effort to get this finished now as it needs to fly.

Drones, Red Kite, Geese

There were already 4 drones at the field when I arrived this morning. One was flying away from the main area, so I invited them over to join us in the middle, but they never did. He was flying a DJI Phantom around where he was standing for a while and then left. As for the others, there was a DJI Inspire flying, a camera equipped white foam twin boom FPV plane and a vortex quad, and there was another DJI Phantom, but to his credit he also had a home built Spitfire from a Internet plan. It was one of those which are built up using foam boards, but it flew really well. A little while after me there was the EFlite Advance and another guy on a bike with a Vortex quad in his backpack. All in all we were outnumbered by drones.

Some aerial footage of my RS352 taken with the HuBSan X4C. Don’t forget the 20mph wind and the fact that a HubSan is about 38g. [link]

By this point it was getting very windy indeed, despite the bright sunshine, so my four flights with my RS352 were all a bit of an experience. It’s still making a slightly different noise with its new motor shaft, but nothing has come loose so far. The prop adapter does need some attention, though, as I could see that it was moving forward considerably every flight. I didn’t even need my home made feeler gauge made from a Cafe Nero coffee stirrer to see that. It might be the prop hangs on the second flight that did it, but the prop attachment does need some attention before the next flight.

Other than that, not much happened, apart from a couple of geese coming over from the pond to see what we were doing and what was apparently a red kite flying overhead for a while. I’ve never seen one of these before and first caught sight of it coming across from the trees to the left of the car park. At first I thought it was a seagull, but then you could see that it was a big bird of prey. A lot bigger than the hawks we normally get. It was also taking rather too much interest in my plane flying around beneath it. One of the other guys told me that it is a red kite, so I’ll have to go and look it up later. Unfortunately, I couldn’t get a picture of it because of the height. Putting the camera equipped HubSan up would have been interesting, but it would probably have got eaten. It was a bit scary flying it in what was now at least a 20 mph wind, but I did give it a go.

I must get round to editing all the video footage I’ve got from the HubSan later today, but I said I would try and make some progress with the AutoGyro. I’ve got a fair representation of a pilot now, so I need to concentrate on just making it all work.

Fun Flying

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.