Unsettled Weather

At 8am this morning the wind was already blowing the trees around and making the neighbour’s anemometer go crazy. I would have been on the bike this week, so I decided to stay indoors instead. I’m a bit annoyed with myself for not going flying, but I wouldn’t have got much actual flying in because of the weather.

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Instead of flying, I thought I should finally have a look at the 3D printed “Whoop” frame that I’ve had on the bench for the last few months. As always, I underestimated how hard it is to get all the electronics and wiring into such a small space. In the end I cut up another failed 3D print and glued the extra bits onto this one to make a base underneath. This will allow me to fix the flight controller with double sided foam tape and also attach the battery underneath. The FPV camera can go on top. The sellotape in the picture shows where I’ve glued the new bottom piece in place. The PLA material used in the 3D print can be a bit temperamental with cyano, so I’ve left the tape in place for now. With a bit of luck I’ll get it all working later and be able to fly it around the house.

Also, last night I made some final changes to the rudder control rod on the ATOM Autogyro and glued it in position. This now means that all the control surfaces work and I just need to do the final tweaking to make it flight ready. Could it really be that I’ve finally finished it? I’ve only taken about 2 years. My thoughts now are whether I can build an autogyro flight simulator as I’ve never seen one? It looks like I might just have to test fly it the old fashioned way.

Too Darn Hot

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The picture doesn’t do it justice. It’s at least 30 degrees in the shade and probably more like 40 out in the open. I managed to beat the weather, though, and got six flights of the RS352 this morning and one flight with somebody else’s UMX Carbon Cub.

There was me, the UMX Carbon Cub and a guy with his son who had a slightly off trim high wing pylon racing type. I’d seen this model fly a few weeks ago and it went really well then, but has since had a bit of a coming together with the ground. He said it was rolling left quite badly and it did look as though the tail was now out of line. I don’t know whether this is a commercial model or an own design, but it was sorted out and flying again quite quickly. I had my first flight with the Carbon Cub, then flew the RS352 for the rest of the morning trying to get it trimmed out again as this was one of the very rare days with no wind. I say no wind, but when a bit of a breeze did blow up it was very welcome. I nearly crashed the RS352 into the ground at one point which was down to pilot error. I think the heat must have been getting to me as I got the harmonisation between the rudder and aileron wrong and nearly put it into the ground. At low level I rolled into knife edge, messed up the coordination with the rudder input, decided to abort and only just about levelled off and pulled away from the ground. Don’t do that again…

We also had the guy with the FPV wing from a few weeks ago, but this time he was flying a Yuneec hexcopter with RealSense collision avoidance.

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He demonstrated the “follow me” and collision avoidance functions, plus the “wand” controller which allows you to fly it without the radio transmitter. We had an interesting discussion about mapping with drones, point cloud cameras and time of flight Lidars, but I still say that flying a little Carbon Cub is a lot more fun than a computerised drone.

After they left we had a family turn up with a high wing foam cub (it might have been the Multiplex one) and another UMX Carbon Cub. He proceeded to teach his young daughter how to fly the UMX Cub, which she did really well. Then he had a flight with the bigger one and ended up losing one of the wheels while in the air. I was flying at the time, so could only look around quickly and estimate roughly where the aircraft was when he cried out, “my wheel’s just come off”. I was landing then anyway and went over to the spot with his wife and kids while he was still in the air. I got the position just about right, but his wife found the wheel before me as it was lying on the edge of the path.

That was two and a half hours in an oven, so at this point I was glad to be going home. I know I still haven’t finished the autogyro, but it’s been too darn hot this week. All I need to do is to epoxy the rudder link stops, velcro the battery, find some bolts for the rotors, check the controls and do a hang test for balance. It really should fly soon.

Very Hot, Very Humid and Really Very Windy

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The weather’s going crazy at the moment. On Tuesday we had torrential rain and gale force winds that brought all the trees down and caused chaos on the roads. Yesterday and today, we’ve had at least 30mph winds along with extremely hot sunshine. This is probably because the wind is blowing all the clouds across the sky at a rate of knots. The picture above shows a sweeping curve cut into the cloud by an A380 heading off on its holidays. In real life, this looked absolutely stunning with the sun, the plane cutting an arc in the cloud and the vapour filling in slightly behind the plane. Of course, by the time my Android phone had booted up, the plane had gone and the wind had shifted everything and filled in most of the trail.

Anyway, there didn’t seem to be much point in trying to fly today, unless you had a big glider to play with. That would have been a lot of fun, but I picked up two new tasks for work this week, which prevented me from finishing the closed loop rudder links on the Autogyro. Now I’m thinking that I’ve got some extra time and I can use that to finish the building. I haven’t actually made a closed loop rudder like this before, so I’ve been reading some articles on how to do it. It all looks fairly simple, though, so I should have it working soon.

Wow, It’s Hot

It’s been really hot this week and part of me is relieved that there’s a running race this weekend and all the roads are closed, so I can’t go flying. It would have been 40 Celsius at least in the sun, which causes big problems with battery charging and overheating. In this sort of weather I usually bring a sun shade to keep the batteries and electronics cool and just overheat myself.

Anyway, as I said last week, this gives me the opportunity to finally finish building the autogyro. I had a bit of a setback last night, though, as I broke the rudder link rod. If you look at the main picture above, it’s the metal rod linking the two rudder horns horizontally, connecting to the bell crank in the middle. You can see that it’s now got an adjustment bend on the right hand half, which wasn’t there before. The reason for this is that I broke the rod last night when I was trying to adjust the rudders to be central. Originally, I made the rod the perfect size, just as in the instructions. Except that it wasn’t quite perfect and I didn’t like how the rudders weren’t aligned straight, so I tried to put a tiny adjustment kink in the rod and snapped it. To be fair, I should have made it with an adjustment z bend in the first place, but figured that I could do it the hard way and make it a perfect fit. To be fair, it was only about 0.5mm out and I could easily have lived with the rudders both pointing slightly outwards, but I had to tinker with it. Then I made another stupid mistake and put both 90 degree bends for the left and right control horns into the rod before I pushed it through the bell crank collet in the middle. Of course, the hole in the brass collet is only just enough for the rod, so it’s impossible to push a 90 degree bend through the hole. What I did was to gently radius the 90 degree bend to a curve and force it through the collet hole. Then I tightened up the radius back to 90 degrees, taking care not to snap the rod for a second time. The left hand bend where the rod goes into the horn is now more rounded than a square 90 degrees, but it works. By the way, if you’re wondering why I put a loop into the rod for the adjustment rather than a tight triangle bend, I was worried about snapping the rod again, so I just made a nice easy looped bend. I knew I was only going to need 1 or 2 mm of adjustment, so this works fine.

After all that I now need to connect up the closed loop rudder and then all the control surfaces will finally work. I guess that will mean that it’s flyable, assuming the balance is right?

Variety in Flight

It was a perfect sunny morning this week and looking around at the models on display it made me realise how much variety was being flown. Firstly, I got to do the first ever flight of somebody else’s FlyZone Fokker Dr1 (Baron von Richthofen version in red). It looks absolutely amazing, but, like all biplanes, triplanes and quadriplanes, it wants to go straight up vertically with even a small amount of power because of the lifting area. You just have to control the throttle and pitch to keep it flying forwards. It’s also a bit weird because it’s shaped like a box kite and has a high centre of gravity. Turning can be a bit slow with the rudder only control, then you have to be aware of the spiral dive. It’s a very draggy airframe, so it doesn’t glide very well with the power off and takes its time to build up speed again when you put the power back on, so smooth and gentle flying is recommended. I got two flights with it this morning, but it does have a rather strange arming sequence which we took a while to get right. You have to power on the tx, then the rx. Next, go to 100% throttle until the prop buzzes, then go to zero throttle and the prop buzzes again. It’s now armed and you can fly. I think our problem was with the throttle trim being too far down and it not being high enough for the computer to detect the 100% throttle threshold. This was cured with some throttle up trim.

During the rest of the morning we also had the Ripmax VTOL Transition from the other week and also the Opterra. So that’s a Triplane, VTOL tilt rotor and a big flying wing. How’s that for variety? In addition to this, we also had a guy with a micro quad and a Parrot Bebop quad, another generic quadcopter, which kept flying downwind, and a rather errant DJI Mavic, which we eventually determined was being flown by a teenage girl with her family. We could see it in the sky, but it took us a very long time to identify where the pilot was as they didn’t want to come over and say hello.

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As for me, I also got 5 flights with my RS352 now that I’ve fixed the issue with the prop coming off. I bought another spinner nut, which I screwed up nice and tight, plus I needed the original red spinner cone as a spacer. You can see most of this in the picture above.

The strange thing is that, with no wind and perfect conditions, the first flight had the trim almost perfect. Then I launched on flight two with the second of my identical 1300mAh packs and it was pitching down very noticeably. I landed after a couple of circuits and double checked the battery position, moving it back about 5mm, but the nose down pitching moment was still there. I ended up adding 3 clicks of up elevator to correct it. Other than that, the aircraft was flying really well. The next two flights were with different packs (1100mAh), then, for the final flight, I was back to the same pack as flight 1. Logically, this should have been pitching up and I think it was slightly, but not enough to be an issue (if flight 1 flew level, flight 2 pitched down, then I added up trim, going back to the flight 1 pack should pitch up). I’m going to weigh all my packs and see whether I can get to the bottom of this trim difference as it’s got me stumped at the moment.

That’s all there was this week, except to say that the AutoGyro is nearly ready. I spent my free time during the week fixing the prop nut on the RS352, which is why I didn’t do any more. Tomorrow is a Bank Holiday and there’s no flying next week due to the roads being closed for a running event, so I should be able to get some building time in.

Lastly, the weather is unbelievable. It’s been 30 degrees and sunny all week, yesterday it was blowing a gale, this morning was perfect and now I’m sitting here writing this with heavy rain drumming on the roof. The promised storm isn’t far away now, which makes flying on the Bank Holiday out of the question. I got lucky this morning, but any drop in temperature is welcome.

Propeller Cubed

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Look, no propeller!

Everything seemed to be coming in threes this week. On my first launch with the RS352, the propeller came off as I was about to throw it. I re-fitted it and went again, only for it to come off 20 seconds into the flight. The propeller was recovered and fixed on the aircraft again, resulting in a successful 8 minute flight on the third attempt. After that, the next flight was uneventful, then, on flight 3 on my third battery pack, I lost the prop about a minute into the flight. By this point I was getting quite good at landing with no prop, which is not the same as a normal landing with the motor off and the prop windmilling. As soon as the prop came off, I immediately powered down and circled around the point in the sky where the prop was slowly falling to earth so that I could see where it landed and recover it easily. Without a prop the RS352 actually glides very well, so you can stay in the sky a lot longer than you would expect. So, with both prop and aircraft safely recovered, I decided to cut my losses at this point and not fly again.

Prior to all this excitement, I also got to fly a Silverlit V-Jet Mini. This is a very strange “toy” aircraft in that there is no pitch control. The left stick only has throttle, but the right is split into lower and upper sections (elevator axis). In the lower position, the wings are vertical and the aircraft can take off from the ground vertically. Move the elevator stick forward to the upper position and the wings move into a more horizontal position for forward flight. Left and right control in either the upper or lower position manoeuvres by changing the power to the motors. We had a play with this for a while, and it was quite windy, but it was virtually impossible to control. The first thing to realise is that there is no pitch control, so you have to use the throttle to control the rate of climb. The temptation is to move the elevator, but there isn’t one and that just moves the wings to the other position. Left and right took a lot of effort to start it turning, followed by an overshoot because then you couldn’t stop the turn. It was very windy, though, and this type of aircraft might work a lot better in dead calm conditions because of how the wing is always at a high alpha position, even when set horizontal. It still looked to have about a 30 degree incidence when horizontal. It was fun learning how to fly it, so maybe we should have another go in the Summer?

Returning to the number three, I also launched an FPV flying wing three times today. The owner was having problems getting it to fly, but launching is difficult because of the rear facing motor. All I could suggest was holding the leading edge and doing a partial discus style launch. The motor was powerful enough that it just needed a shove into the sky, so my first launch was really quite good. Unfortunately, it crashed because the pilot had no elevator control. He made some changes, we tried again and the result was the same. On the third attempt it flew for longer, but still no authority on the elevator and this time it did more damage. The motor mount broke and he only had cyano to fix it with, which didn’t want to set.

We had an interesting discussion about FrSky radios while trying to sort out the FPV wing as he was using the new Horus transmitter. His opinion is that the European firmware in all the FrSky radios (Taranis and Horus) has a reduced range compared to the US firmware and has other bugs in the telemetry and radio link, not forgetting the lack of support for the full range of receivers. So, he was using a brand new top of the range FrSky Horus, but with an 800 MHz transmitter module so he didn’t have to use the rubbish tx module in the Horus.

In addition to all these aircraft, we also had somebody with a “Faze” electric glider. At least I think that’s what it was called. It flew really well in the now deteriorating conditions. Look at the photo below and take a close look at the wheels. That’s the wind again.

 

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We also had a Horizon Hobby mini helicopter (~50g) which flew insanely well in the conditions, a Multiplex Twinstar and a Blade 350QX drone. The drone’s return to home is interesting as it finds its way back a lot faster and with more authority than the DJI ones which I’ve always found are very hesitant to set back down on the ground. Talking of DJI, we also had a youngster with a Mavic, but he didn’t want to talk to us.

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I also had another stroke of luck this week and I’ve found the missing motor from when I was making the micro drones for the workshop back in March. I was using my hand drill to open out the holes in some brass collets to hold the wheels on my autogyro and there it was stuck to the drill body. At least now I know that I’m not going mad and it didn’t just disappear into thin air. I must have put the motor down close to the drill and the two got stuck together. Anyway, as you might have guessed, I’ve actually made some progress with the Autogyro this week. The blade balancing is done, the wheels are on and I just need to sort out the controls. With the blade balancing, I couldn’t manage to bolt two blades together as the film is far too slippery. Eventually, I hit on the idea of using the double sided sticky foam pads from the quadcopters to make the blades stick together so that I can balance them.

That’s it for this week, I’ve got to figure out how to make an autogyro work.

There’s Nothing Happening This Week

It’s bright and sunny with a strong wind this morning. Precisely my least favourite weather conditions because the sun makes me think I should be outside flying and I keep looking at the clouds skimming across the sky and thinking, “no…”.

Not that it really matters much, as I’m trying to complete a project for work at the moment. This is getting really silly, as, last week I had a presentation to finish for Monday and this week I’m building a voice user interface for a demo on Friday. I keep telling myself that I’m going to finish the autogyro, but the time just isn’t there. Never mind, though, talking computers are fun to play around with.

I do need to make some time to finish the autogyro, though, as RCM&E have just featured an Avro 504K biplane plan, which is something I’ve wanted to build since I made the Airfix kit many, many years ago. On the subject of RCM&E, having picked up the latest copy, I’m really not sure about their new layout. It’s just not as interesting as it was before. All the feature pages use the same format of top two thirds pictures and text in the bottom third of the page. It was better when the images were placed around the text and different articles had different layouts to suit. The show reports always had lots of pictures and a running strip of text along the bottom, which was good for a very visual article. Now, all the articles look like that and there’s no variety any more. Maybe I’ll just get used to it?

OK, I need to get a speech recognition system working by this evening, or I’m going to have some serious problems later this week.

Where is Everybody?

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It was just me and the wildlife for most of the morning until a couple turned up with a Mavic drone right at the end. They weren’t having anything to do with me and set up about 50 metres away, but it was nice to see her showing him how to fly it. I said hello on my way home, but that was about it.

The weather wasn’t exactly good, but I managed 5 flights with the RS352. That’s two with the new packs, two with the year old packs and one with a field charged new pack. On the first flight it just didn’t want to fly right. The aircraft’s nose was in the air, there was no penetration and lateral stability was non-existent. I don’t know whether it was the conditions, but I ended up putting in four clicks of down elevator. It actually flew straight and level if I popped the flaps up, then nose down when I dropped the flaps back to the normal flying position. It’s strange, because I was getting trim changes like this the last time I flew it. However, this time around the weather was appalling. It wasn’t immediately obvious, but I’m sure there was turbulence that was rocking the aircraft all over the place. I tried the CG balance dive test and it was absolutely neutral, so that might be the new packs which are slightly lighter, plus I might have added weight to the tail when I glued the skid back on two weeks ago. It’s a very minor change though as I usually fly the RS352 with a touch of positive stability. Actually, I cut my first flight short after one circuit as I was flying in clear glasses and decided immediately that I wanted my normal aviator sunglasses back. Flight one was a flight of two parts, then flight two seemed better. With the older pack on flight three, there was noticeably less power and it was flying really smoothly now. Flight four on the other older pack seemed like there was only just enough power for flight. I think the pack has gone as it didn’t feel like the power was consistent throughout the throttle range. I was flying on 100% for a lot of that flight, but the weather was definitely more blustery. The final flight straight after on the newer pack was a lot better, so maybe flying speed was playing a part in the increasingly windy conditions? It’s all very odd, as it felt like my control inputs weren’t getting to the plane at some times, but in this weather it’s very hard to tell. All I can say is that, when the aircraft was back on the ground, I could see it “wriggling” around in the wind like it was in the air, so I’m going with atmospheric interference for now. I’m still going to do a full system check, though.

Well, that’s it as nothing else happened. I’m still in the process of not finishing my 99.9% complete Atom Autogyro due to pressures of work, as I’ve got a presentation to finish for tomorrow. Hopefully next week will bring some good weather.

A Very Windy Bank Holiday

It’s the May bank holiday this weekend, but the weather’s not co-operating. Today started out very windy and just got worse as the weather front got steadily closer. Needless to say, there’s no flying this week, so I’ve been fixing up the indoor micro quadcopter that I 3D printed last week.

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It’s a “whoop” or “Inductrix” style quad with four enclosed rotors intended for indoor FPV flying. This one has space for the F3 Evo controller that I bought a while ago, so it should be a lot more interesting to fly than the modified HubSan ones.

When I say, “fixing up”, I still haven’t managed to get a successful print of this design yet. This one was from a LeapFrog HS, but the printer isn’t extruding the PLA very reliably. This shows up really badly in the supports, and you can see where it’s not printed properly in the photo. The top in the photo is the bottom when printing, so that’s the bit which sits on the plate. The guard rings aren’t too bad, but the thin stator vanes don’t come out at all well.

This is the best print I’ve had so far, and it looks like it can be modified to work, so I’ll just have to see how it goes.

Just to finish on the topic of the weather, I saw this really strange effect this morning:

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It looks like the con trail from an aircraft is casting a shadow onto the cloud. It took a while for me to get the camera, but to start with, the shadow and the white con trail were very close together, gradually diverging as the wind separated them.

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 HorizonĀ 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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