Month: September 2017

Crazy Last Days of Summer

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The weather seems to have got the memo this week and we had warm sunny conditions with enough breeze to hand launch an autogyro. You can see from the picture how I’m stopping the blades from spinning with a rucksack.

It was crazy this week as I think everybody saw this as probably the last good day before the weather turns Autumnal. We had three drone parties in various positions around the field not talking to us in the middle. One was a father and his two kids with a toy drone (Syma?), another had a more professional one at the opposite end of the field, while the third was a couple I’ve seen most weekends with a Mavic. They were right in our landing zone, which wasn’t great. As for everybody else, there was a guy flying a Mavic when I arrived, plus someone I’ve known for ages on his bike with a UMX Fokker DR1. Shortly after this we had the guy with the Cobra, along with his son and daughter, then the Skysurfer, a guy with a DLG from a couple of weeks ago and a lady with a micro drone and FPV. Finally, towards the end we had another two guys from last time with another Skysurfer (or Bixler?), a small helicopter and a drone.

As for flying, in order of take-offs I flew: the Fokker DR1, the Skysurfer, my ATOM Autogyro, my RS352 and finally my 3D printed Dimorphodon quadcopter. The DR1 was a bit of a handful in the wind as flying a 30g box kite on a windy day is always interesting. Anyway, it was really pitching up badly this time, which I can’t remember it doing when I first flew it after its front end repair the other week. I ended up putting in about 10 clicks of down elevator, but I think it’s partly thrust line as things definitely improved when the motor was off. I did some fairly impressive vertical aerobatics while I was busy hitting the down trim, but then the motor wouldn’t come back on, I tried going back to zero, then 100% to clear the ESC, but there was no power so it was time to land. Back on the ground power seemed to be restored, so I can only think that the aircraft had had enough and decided it wanted to be on the ground more than getting blown about in the air.

Next up was the Skysurfer which I did the maiden for a few weeks ago and thought was an absolutely wonderful aircraft to fly. This time, the launch was a bit too interesting. I elected to hand launch and fly, but once I released it, the aircraft dived into the ground. There was a moment when I would ordinarily have cut the throttle, but the motor’s at the back and up top, so I just bounced it off the ground and slid my way into the air. This time out it was pitching down badly. Why I’m not quite sure as it had only had its wing fixing improved since last time out. Anyway, I got it sorted with about 10 clicks of up elevator and a bit of right, then let the owner have a fly. It wasn’t liking the conditions much, as it felt a bit spirally unstable in a tight left turn. It still flew well, though and the owner had a few more flights on his own too. – NOTE: it occurs to me afterwards that I’ve just flown one aircraft that was pitching up and needed me to fly with 50% down elevator, then switched straight to another plane that was pitching down and required me to fly with 50% up. It’s all good experience.

 

OK, so I fixed the ATOM autogyro yesterday and now it was time to fly it. One alteration that I made was to put the receiver on the rear wall of the pod rather than inside, as the internals are rather busy. Facing into wind and holding the nose vertical, I waited for some significant spinning to happen. Sure enough, it started humming and the wheels started to vibrate, which is the signal that the rotors are spinning fast enough to launch. But, it failed to really fly. I find myself having to tilt the rotors forward to prevent it going over my head, it flies away from me, but never seemed to be really on step enough to gain height. I had three attempts and every time it flew forwards, rolled and yawed around to the left, lost what little height it had and hovered in for a landing having not quite completed a full circuit (at about 10 feet height). I’ve switched to a 9×6 prop from a 9×4.5 to try and give it a bit more bite, but it hasn’t made any difference. Also, I’m using 0.8mm shims under the blades, but I did this as two 0.4mm shims on top of each other. The top one was sellotaped on to make it removable, so the next obvious thing to try was to remove the extra shim and fly with just 0.4mm. This didn’t seem to make any difference, so I’m going to have to take this home and have a think about it. The aircraft has flown from a hand launch in this configuration (with a 9×4.5 prop though) as I had a 4 minute flight. My feeling is that it’s the launch and not getting into the right part of the flight envelope. The left bank on launch says to me that the rotors aren’t up to speed and then it never gets out of this stalled mode. I was flying with the throttle at 100%, but with no noticeable effect on airspeed, rotor speed or height gain. Something isn’t right here, so I need to do some more homework on how to fly autogyros.

After that I had three flights with the RS352. I’ve only just realised, but this aircraft’s birthday is around this time of year. I bought it in early October, but I can’t remember if it’s now 4 or 5. I’ll have to have a look, but I like to live with my aircraft for a long time. I don’t know whether it was my new charging regime, but the good LiPos which I put in for the first two flights just didn’t seem to have the punch that they normally have. I used the storage charge of 3.88v two weeks ago, then fully charged them Saturday night and used them without topping up on Sunday morning. Normally I would top up and fly, so that might be the difference? I was a bit preoccupied with the autogyro though.

Finally, I flew the 3D printed Dimorphodon quadcopter that I made a while ago. I’ve never had a real go with this until now, but it was a lot of fun. It’s based around the HubSan flight controller and I had to use Expert mode because of the wind, but it doesn’t fly like most other quadcopters. I always wonder how much is to do with how an aircraft looks, but with its odd shape and more aircraft like wings rather than being square like a quadcopter, it seemed to want to spin round on the spot. It was great fun to fly, but I need to do something about those pointy wing tips as I managed to stick one in the grass at one point. That can’t be safe, so I’ll round them off before I publish the STL file for other people to make.

One final thing is that I’ve taken two sets of photos of the autogyro in order to attempt a 3D reconstruction to build a mesh for my flight simulator. I did one inside and one outside, so I’ll run that once I get back to work. The more I get into autogyros, the more I want to build a simulator for one.

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Another Work Day

There’s no flying this week because all the roads are closed due to a cycle race. It doesn’t matter anyway, as I’ve spent the whole weekend working again. I still haven’t quite finished fixing the autogyro, but, if I can finish everything in the next few hours, I’m going solarfilming.

 

Weather and Work

It started out sunny this morning, but the weather deteriorated within about an hour. The wind was enough to make flying out of the question, but I’ve really spent too much time on work stuff this weekend. It’s going to be a hectic week and I’ve lost most of my weekend to it.

I have been able to do bits and pieces on the autogyro, though, and it’s almost flight ready again. All it needs is the solarfilm put back on the fin and a bit of tidying up and equipment installation. Repairs are a special skill, but it is always easier to fix something than build from scratch, as you already know where everything needs to go at that point. I should do a follow-up post on how I repaired it, but, for now, I’ve got to get back to work.

Sunny September

Well, it started off sunny at least, but the weather forecast was spot on and it got increasingly overcast and windy towards lunchtime as the predicted weather front brought its rain in. It’s a shame I didn’t have the autogyro, as they had just mown the grass, making a lot of opportunities for taking off from the ground. I was close to having it fixed, but just ended up with too much to do for work again.

I thought I was going to be on my own this week, as I had the first flight of my RS352 alone. I’ve changed my charging regime this week, using a new Overlander RC6 charger to store my two sets of 1300 LiPos at 3.84v rather than using my older Hyperion EOS0606i. I still have to use the older charger for my older 1100mAh cells, which have now puffed up very badly and are giving hardly enough power to fly. The change in how I store them is an attempt to prevent the new ones from going the same way, but only time will tell. I would have used the new charger on all four packs, but the two older ones have Hyperion balance connectors, which I can’t connect to the Overlander charger. Anyway, it took a bit longer to charge the good packs from storage to flight charge as I didn’t get time to do it the night before.

After I had my first flight, people started arriving. We had the Fokker DR1 UMX from last week, now repaired. He also brought his son along, plus a Carbon Cub UMX, Corsair, Spacewalker, Striker UMX and a Silverlit helicopter which he gave to me to fix. I flew the DR1 for him while his son was retrieving the car. Considering how windy it now was, plus the fact that it’s basically a box kite that you’re flying, it went really well with its repaired front end. It was wanting to climb badly while having full down elevator applied, so I just flew it with the stick forwards as you tend to use the throttle to control the height with this plane anyway. The landing was absolutely perfect and it just sat there on its wheels looking at me, which was a big relief. It was much too light for the conditions. The F27 Striker was also a bit interesting as I did the launch and there’s not much to hang on to. You can’t bring the power on until it’s released as the prop is at the back, so it only just got away, despite my big push. It was also pitching down badly, so I had to press the trim switch while he continued to fly it. It was extremely agile and positively loved the windy weather though.

We also had two guys with Mavics, one with his wife who also flies it, plus another guy with his wife and two kids plus a Mavic at home. The kids (and dog) loved the aircraft, especially the spacewalker. Then one of the guys from last week arrived carrying a Bixler and drone. His ambition was to learn to fly the Bixler and take it home in one piece, which I think he just about managed. It did take a lot of punishment, though, and I couldn’t work out why it was beeping while it was in the air. It almost sounded like an audible vario, but that would just be stupid? Finally, another father and two sons turned up. The older one had a white foam high wing Cub type trainer, while the other had what looked like a much smaller version of a Bixler, I think with a 27MhZ transmitter? Both actually flew really well, although neither of them was getting the best out of the smaller plane as they kept smashing it into the ground so that the wings kept flying off. With the bigger aircraft, the other guy helped them out as the rudder wasn’t central and various tools were borrowed to make it work. In the end the take-off was perfect and it flew very well in the wind. The only thing that was strange was a tendency for a left to right yawing oscillation under power with the wing tips making small circles in the air. It was most noticeable under full power. Now I’ve had time to think about it, I wonder whether the rudder push rod was bending under flight loads? When he handed the transmitter over to the older kid, he managed to crash it into the ground, but it survived for another flight. I had a sneaky flight with the Carbon Cub while they were doing this. It’s really lovely to fly in these conditions and behaves like an aircraft that’s much bigger. This must be a result of the AS3X system.

Anyway, I lost track of how many flights I had with the RS352, it was either four or five, one of which we were trying to fly in formation with the Corsair. It was a lot of fun not hitting each other, but the two aircraft just have different flying speeds, so it was never convincing. He can also fly for about 2 minutes longer than me.

Then it was time to go home, which was probably a good idea because of how threatening the clouds were now looking. It was getting very black.

The autogyro should be finished by next week as the fin is back on and I’ve straightened the bent motor shaft.

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Actually, I might have another go at the shaft because it’s still very slightly bent. Look at the gap between the case in the pictures below:

It’s only fractional, but it might cause vibration problems. The spruce longeron is completely fixed, though, so I just need to cover the tail pieces and re-assemble everything again for the airframe to be complete.