Easter Sunday 2017

It’s Easter Sunday today, but the weather seems to be following the same pattern as yesterday. It’s bright and sunny, but with a strong north wind. I decided to stay at home this week and it looks like a good decision as the wind has steadily increased throughout the morning. This isn’t like it was in the old days when I remember getting in four consecutive days of flying over the Easter weekend. One time, I remember, I brought a different model every day and somebody remarked on the fact that I had flown an F16, a Vampire, a CAP231, a flying wing and a glider. It used to be that I always ended up flying my new models at Easter, so, this year, I had in my mind adding an AutoGyro to that list.

I’ve spent all morning covering the blades with white profilm. However, the more observant amongst you might notice that I’ve only got as far as finishing one of the three blades. This solarfilming is taking a lot longer than I remember. Either I’m really out of practice or the blades are just an awkward shape to cover? Trying to keep the square edge on the bottom of the leading edge is causing me problems. Normally with an aerofoil you can overlap bottom to top on the leading edge and there’s a nice gentle curve that you can smooth the film down on to. With this being square on an autogyro (according to the instructions, the blades won’t start to spin without this edge, but then I’m no expert on autogyros), it makes the covering harder. Not much harder really, I just always take a while to get going with covering jobs. Once I’ve got back into the groove, then I get a lot faster. I’m hoping to be done by this evening, then I’ve got three more days of holiday to finish the rest of the aircraft.

Vertical Take Off

It was really hot and sunny this week. The only thing that let it down was a really devious wind. Devious because, one minute it was really strong, then it was gone, then it was from the other direction. This week’s flying session was really good though.

First off, I bumped into a really nice couple with an Inspire drone. They weren’t sure if they were in the right place because the board still has no rules on it. He had done all his homework, though, and knew exactly how far he had to keep away from people and that he couldn’t just fly it anywhere. I’m fine with that.

I then had a flight with the RS352 using a new LiPo, which makes it go like a rocket. The flick rolls were also something else, but more on that later. Then I had a flight with somebody else’s HobbyZone Champ, where I did actually persuade him to fly it for a bit. It was really too breezy for it, but these UMX lightweights (~30g) handle the wind better than you would think. After that I had another RS352 flight, but, noting how the trim seemed to have changed, I tried a balance test in the air. I gained lots of height, turned the motor off and pointed it at the ground. It immediately tried to tuck itself under, so I must have been flying it with the balance right back at the neutral point, or a bit behind, so that it was verging on unstable. Well, that explains the flick rolls. I made some pitch trim changes until I was happy flying it, as you could see the pilot induced oscillations. What I can’t understand is that I did a ground balance check and it all seemed fine. The new LiPos weigh 100g, the old ones 102g and the very old ones (now retired) 108g. I can’t see that making a huge difference and I do move the balance around depending on conditions anyway. The result of the pitch trim is that it’s now much closer with the flaps down or up, where flap up before resulted in a big nose down pitching moment. I always flew with the flaps down anyway, so it was trimmed to fly slower with the extra wing camber, which worked better. The point now is that I’ve been practising harriers, which this aircraft just does not want to do. It’s been impossible trying to get it to settle into a stable 45 degree nose up forward flight mode, but now, with the camber flaps retracted (zero flap), it seems easier. Maybe the answer is reflex, so I’ll have to do a bit more investigation?

I had another two flights with the RS352 using the older LiPos, but it was getting windy by this point and I didn’t want to push the aircraft too hard. In fact, the wind had damaged it, although this happened on the ground. I lost the tail skid when the wind blew the aircraft around 90 degrees in the yaw axis while it was sitting on its wheels. This ripped the tail skid out, but I managed to find it, so it’s an easy repair. I also had another flight with the Champ, giving its owner some more air time, before almost crashing it on landing when the wind whipped up just at the wrong moment in the wrong direction. I touched the ground at about 45 degrees off forwards, which resulted in it flipping over, but with almost no speed and no damage.

At this point we also had the Zeno and Heron (which really flew well in the conditions), a small, green Edge 540, which I haven’t seen since last year, and the Nieuport from last week was replaced by a new Ripmax Transition VTOL aircraft. The first flight of this was interesting to say the least. It launches vertically off the ground like a quadcopter, with all four motors on their wing pods pointing upwards. Closer inspection revealed that it has two positive pitch props and two negative pitch in diagonals just like a quadcopter. For control, it also has an elevator (elevon?) on each half of the rear wing. The motor pods can also be rotated forwards to transition to forward flight.

This wasn’t its maiden flight, but the take off was a non-event. It just lifted up, drifted across the field in VTOL mode, but a minute or two into the flight, I saw the right rear prop come off. At this point, I thought it would immediately flip over and crash, as I would expect with a quadcopter, but it continued to fly upright, drifted and yawed around its central axis and crashed fairly lightly in some grass. That’s very impressive control from the flight controller, because we know the pilot didn’t do anything. He hadn’t seen the prop fly off. What followed next was a hunt for the prop, as two of us spotted its position when it landed, but then followed the aircraft down and lost the exact spot. Nevertheless, we found it lying in the grass after a bit of a hunt.

Back at the pits and some investigation showed that the tilt rotor mechanism was damaged, but not badly. There’s a single servo inside the fuselage with some really thin piano wire (2mm or 3mm? push rod type), which drives the mechanism. The servo had come away from its mount, so the motor pods were free to move. This is where we had a bit of an accident and got really lucky. Being a computer flight controller, it doesn’t work like a regular fixed wing aircraft, but more like a quadcopter, which you would normally arm or unarm. He clicked the throttle trim switch, something happened and the aircraft flew off on its own. It crashed a little way downwind, but managed to miss all of us standing around it. The moral of this is never to trust a computerised control system. The arming sequence on a quadcopter is there for a reason. Here, we have what looks like a fixed wing aircraft, but with four props all pointing upwards in our direction. It needs to be treated like a quadcopter and assumed to be live whenever the LiPo is connected. OK, that’s the same as a fixed wing aircraft, but the aircraft has the prop at the front and pointing forwards, which you will be pointing away from people when you connect i.e. nothing in the disk of the propeller and nothing forward of the propeller. The computer control system of the VTOL aircraft is an unknown quantity here, so always assume it is live.

Anyway, it wasn’t badly damaged when it was recovered, but it was discovered that the nose wheel had gone missing. This is where there was a difference of opinion, as the pilot thought it was still present after the first crash, while somebody else remarked that he noticed that it was sitting very low to the floor when we were examining it in the pits after the first crash. So, the pilot went to the second crash site to look, while we went to the first. We won that round of the Easter egg hunt too, as it was just sitting there in the grass at the site of the first crash. He’s got all the bits and it looks like a simple fix, so I’m hoping to see it flying again fairly soon, as it looked really stable in the air and rather interesting to watch.

I had to go at that point, but there were some kids walking over with a drone, a glider and a jet model, so it was still very busy. We also saw somebody flying a big glider over on the other field, which was a bit worrying, and a guy on a big skateboard with another drone.

Sorry there are no pictures this week, but it was a lovely day and I just flew stuff all morning.

Spring is Here!

It’s bright and sunny. There’s not much wind. It’s almost perfect weather for flying and I managed six flights with my RS352 and two with a UMX Taylorcraft.

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We’ve also got a new board to mark the flying site, but it’s not got anything written on it yet. Apparently, it was put up last week, but I wasn’t around then.

Anyway, my first fixed wing flying since February was with somebody else’s Ares Taylorcraft. This is a lovely little model, rather like the Champ, and I really like the dark red colour scheme. There was a bit of wind and it’s so light that the rudder doesn’t seem powerful enough at times. You hold full rudder for ages and nothing happens, then suddenly it bites and you have to back off. Most of the time, though, you could push it around the sky with ease. My second landing going with the wind as the ESC had cut was almost perfect, running along the ground on the wheels for quite a distance until it got stopped by a clump of grass.

In between the two Taylorcraft flights, I tried out the first of my new Hyperion G5 SV LiPos. The power available was frightening compared to the 1 year old EX G3 LiPos that I’ve been using. It’s going to be interesting to see how these last, as my original 3 year old CX G3 LiPos are holding up better than the newer ones, which have puffed up terribly. The very old ones will now be retired, followed soon by the 1 year old ones I suspect. Just charging the new cells back up now, I’ve only taken 450mAh out of the 1300mAh pack, so I was being very conservative with the first flights.

I got 2 flights with the RS352 with the brand new cells, then the 2 old cells and finally the 2 very old cells. These were basically trimming flights, as this was my first opportunity to fly in calm conditions since I changed all the servos over at Christmas. The only thing to note was that on the final two flights with the very old cells, the balance was completely off, with the model wanting to dive into the ground. This is weird as I’ve flown with all the old cells interchangeably and not had this problem before. I’ll have to do a balance check later just to try and work out what was happening.

In addition to me and the Taylorcraft, we had a Multiplex foam Extra 300S, a Nieuport biplane, a whole host of foam FPV aircraft (including some really dinky twin boom ones) and a drone. Then finally, an HLG flyer who we’ve seen regularly over the years.

I just love biplanes, so I tried to get a shot of it in flight, but this was the best I could manage. It’s right in the middle of the frame if you look closely at the big cloud.

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Finally, it looks like the skylarks are back again. I saw one of the little critters hovering and you could hear them all around singing to each other.

OK, so with no more drone masterclasses to run, I’m now free to finish off my Autogyro. I tend to test fly all my new models around Easter, so that’s a good deadline to aim for.

March Winds, A Lost Hour and A Drone Workshop

I don’t think I’ve actually done any fixed wing flying in March this year? This week it’s very windy again, but bright and sunny like Spring’s finally here, so it’s just annoying to be sitting indoors. I am completely exhausted from losing an hour’s sleep as the clocks went forward this morning. Then there was the Drones4Good “Engineers Save Lives” event that we ran yesterday. We had two new frames this time around: Dimorphodon and AeroTurtle.

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If you’re wondering what the event itself was like, then this shows things in full swing:

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You can just see one of the butterflies hovering in the foreground.

I also managed to get some drone to drone shots (drone squared?) with the new HubSan X4C HD camera filming the butterfly in the air:

I’ve been trying to get a shot like this for ages, but it’s really hard to do. I’m also not that impressed by the video from the HubSan’s camera. We were getting better video off of the camera in the custom built FPV quadcopter that we also had, but didn’t have the ability to record from it. The quality of the FPV image in both the FatShark goggles and the Black Pearl display was so good it was frightening. It also turned into an unexpected opportunity for the children to take selfies of themselves by photographing the screen while pointing the drone’s camera at themselves.

That’s three of these events that we’ve done in total now since March last year. I think we lost quite a bit of the kit this time around, but I still need to check it all over on Monday. The frames actually survive remarkably well as I saw a few of them hitting the concrete floor quite hard. We have 5 sets of kit at about £35 each, so it was always intended to be expendable. Anything we can salvage afterwards is a bonus and we got to teach the children how it all works, how to fly them responsibly and how we use them for aerial surveying.

Next week everything is back to normal.

A New Thing Spreads Its Wings

It’s blowing an absolute gale this week, so I’m still grounded. That’s probably a good thing, though, as it’s the drone masterclass next week and I’m snowed under with work.

Earlier in the week I got a new 3D printed quadcopter frame to fly. It’s a very strange and mysterious creature from the early Jurassic. Can you guess what it is?

OK, it’s the Dimorphodon model. When I was filming the first flight, it was a bit dark and I looked back at the flight video and saw that the shadow it cast on the wall looked just like the fossil picture I was copying it from. So, afterwards, I got a desk lamp and hung the model on a piece of wire so it cast a shadow. Following a tricky bit of juggling with the Dimorphodon on a wire, swinging around in front of the lamp while I tried to work the camera one handed, I got the photos above. If you look at the pictures, the wire it’s hanging from is obvious, but it does look like a fossil.

We decided to go back to the model with the wings spread out full span, rather than the folded wing model that I showed a couple of weeks ago. I’m really pleased with that decision as the results are fantastic. I’ve always wanted my own flying pterosaur ever since I saw the one in the movie “War Games”. Of course, a bigger, gliding, version would be better, but a micro quadcopter will have to do. These images show what it really looks like:

And, yes, the head is held on by foam tape, but it’s all I had and I was in a hurry to film it flying. I think the flying videos are going to have to wait until next week.

That’s it for now, I’ve got an aero turtle to make…

Still Grounded

It’s been drizzling with rain all morning, so, in retrospect, staying indoors was definitely the right choice. I’ve built an FPV micro quadcopter for the workshop we’re running in a couple of weeks.

OK, so the camera’s a bit wonky, but I’m waiting for the glue to set before I fix it properly. I’m quite pleased with this as the flying weight is 54.9g, whereas a regular HubSan X4C (HD) is 51.0g. This is the quadcopter frame from the “Acrylic Blue” video in January, which is the lightest I have. The FPV camera is a cheap one which only cost £30, but weighs over 9g, compared to the 4g weight on my £50 Hyperion camera. This way, I’m hoping to get flights of over 4 minutes out of it, but I haven’t done a proper duration test yet. All the electronics check out, using both the FatShark Goggles and my Black Pearl screen. To make the screen work, I’ve made myself a custom power lead which has the Black Pearl 12v jack plug on one end and a Deans connector on the other. That way I can use my regular flight LiPos to power it as the screen’s internal 3S battery is completely wrecked. The funny thing is that the goggles worked straight away, but I had to switch the screen from NTSC to PAL. I’ve had both of these working with my Hyperion camera on NTSC previously, so I can only think that I must have already switched the goggles and just forgotten about it? For anyone who doesn’t know, once you get the right band and channel, you should see some sort of image that you recognise. If it’s black and white with the image rolling slowly down the display, then the NTSC/PAL setting is wrong and the transmitter and receiver are using different modulation schemes. I haven’t found any compelling reason for choosing one over the other yet, so stuck with the PAL that the camera was set to. It’s usually configurable at both the transmitter and receiver end, but the cameras are tiny and usually harder to figure out. The video looks really good, so I’m looking forward to flying it around the house (with blade guards added).

That’s ticked off my main task for today, but now I’m off to fix the geometry on my Dimorphodon quadcopter frame so I can do a 3D printing test tomorrow.

I believe it’s called seasonal weather

It’s blowing a gale with heavy showers this morning, exactly as forecast, so I wasn’t planning on doing any flying. It’s probably a good thing too, as I spent the whole of yesterday filming how we hack the HubSan X4C electronics for the next drone workshop that we’re running at the end of the month.

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I 3D printed myself a mount for the GoPro camera on Friday, which came out really well. It’s the orange cylinder that you can see in the picture, clamped into my drill press taking the place of the drill. The GoPro is screwed to the underneath of it, just visible in the picture. Originally, I was using a small tripod mount, which I gaffer taped to the drill press, but this works a lot better for filming. The picture is showing the end of the conversion process, when I have the four motors from the HubSan and the flight controller with wires attached and connectors which let you plug it together easily. I’m going to edit the video later today, so I’ll see how it turns out. I’ve had several goes at filming this process, having now converted 7 of them, but never got any satisfactory footage that I could use.

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In case you’re wondering what the flight controller and motors attach to, my Dimorphodon frame is almost ready for printing. Whether this will actually work or not is anybody’s guess.

I’ve also got to get the micro FPV quad working, for which I’ve used my super light depron and acrylic frame. This compensates for the heavier Eachine EF-01 AIO camera, which is 9g compared to my Hyperion version weighing just 4g. It checks out with the Fat Shark Predator V2 goggles, so I just need to get everything attached to the frame. Then I’m going to solder a 5.5mm power jack to Deans connector to power my Black Pearl screen so everybody can watch without having to use the goggles.

Maybe I’ll get some flying in next week, but for now I’m busy building stuff?

 

Downtime

The weather has been appalling recently, with gale force wind and rain, so I’m stuck inside this weekend. I’ve been keeping busy by converting another of the HubSan X4Cs for a workshop we’re running in March. It took all day as I’ve been filming the process as I go along, so it should be interesting to see how the final video turns out. This time around we’ve also got a £20 FPV camera so we can give them a go with the FPV goggles.

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Also for the workshop, I’ve been playing around with a new design of 3D printed frame. This time, it’s a Dimorphodon dinosaur skeleton. It’s a bit ambitious, and I’m not sure if it’s going to work, but it’s been fun sketching it out. I think I’m going to stick with the flat style of 5mm high extruded frame rather than go the whole hog and make it properly 3D. I’m not entirely sure where I’m going to put the four motors yet, though.

In addition to this, I’ve finally got two new LiPos for my RS352.

I opted for some Hyperion 1300mAh LiPos, similar to the original ones which worked really well. I ordered them from Robot Birds on Sunday and they had arrived by Tuesday. Fantastic, but those XT60 connectors will have to go as I use the Deans ones. I would have swapped them over today, but I’ve been filming the HubSan conversion process for most of the day. That can wait until next Saturday when, hopefully, we’ll have better weather. It sounds like the wind is trying to tear the roof off at the moment.

 

Where Did the Sunshine Go?

I got up this morning and it was bright and sunny. When I got to the flying field, though, it was overcast, windy and cold. I don’t know what happened, but everybody else who arrived had the same experience. The weather just sort of changed between the car park and the field.

It was a very busy morning with the helicopter guy there practising when I arrived. He looked like he was trimming a new setup as he was very deliberately going part way through a manoeuvre, then stopping and trying the other way around.

Then I had a visit from a swan who flew around the field and then flew back in the direction he came from. After that there was a father and two sons who had a foam Piper Cub aircraft. I’m not sure who made it as there weren’t any markings, but it went surprisingly well in the, now extremely gusty, conditions. Both the dad and the older boy had a go at flying, with the boy really throwing it around the sky. He managed to hit the dustbin with the prop at one point, but it kept flying, only to be stopped on a later flight when he did a half loop to inverted and then pulled back instead of pushing down and slammed it straight into the ground inverted. I’m impressed that a small foam Cub could fly in that wind, especially rolling and flying inverted on just rudder and elevator. They’re now looking for a first aileron model to improve their skills on.

After that, the EFlite Advance arrived and the guy whose Hurricane I flew a few months ago with an electric balsa glider called a “Faze”. This was covered in black and red film and flew very well. He’s now looking at a Fokker DR1, so that should be interesting. Also, I think it was the guy who had a DJI Mavic in a backpack a few weeks ago with his son (plus Syma drone) and a friend who he was teaching to fly with a buddy box. They had the Hobby King Bixler (Easy Star clone) and a very boxy looking aircraft which he had started building in the year 2000. Apparently, the SIG elastic bands which held the wing on were authentic 17 year old ones, but had been stored in a box and were fine to use. This wasn’t its first flight, but the first one of the day was just as I had to leave, although it seemed to be buzzing around the field at a rate of knots. Also flying at some speed was the Stryker, back after not being around for a few weeks.

My flying this week was slightly curtailed by my LiPo situation. The first flight didn’t feel like all the power was there. This was with the newer (1 year old) 1100mAh Hyperion EX G3 cells. These are 3S 45C cells, so I should be nowhere near their limits with my RS352, and yet both packs have puffed up and seem to be on their way out. In contrast, the older (4 years or more) CX G3 1300mAh cells have puffed less and lasted better. Both now have two cells where the voltage isn’t holding up, but still fly better than the newer ones. So, the first flight was not much over 3 minutes, then the second one on the other pack of new cells had a lot more power and lasted 6 minutes. The flight with the first older pack, after charging to bring the two duff cells up to voltage, had the most power and was around 6 minutes again. I never got a fourth flight as I ran out of time before the two duff cells on the final pack got over 4.0 volts (I got them up to about 4.15 on the other pack before aborting the charge and trying them out in the air).

As for the flying with the RS352, I’m still trimming it with the new servos, so just a few cuban 8s, loops, rolls, flick rolls, stall turns and spins. The conditions weren’t really up to much more than just trying to stay in the sky. The conclusion is that I need new cells, so I’m off to do some shopping.

Winter Weather

It’s cold. It’s windy. It’s dark. We had sleet and snow yesterday and today’s not much different. I might have got some flying in this morning, but I decided to stay indoors in the warm instead. It hasn’t exactly rained, but there’s been this sort of mist that’s in the air.

I’ve been making butterflies instead this morning.

It’s a 3D printed frame for a micro quadcopter that we use for the Drones Masterclass that we run at work. The next one is at the end of March, but the 3D printing and all the manual work required to make them fly takes up a lot of my spare time. This one’s ready to go, so I’m going to spend the rest of this afternoon trying to get my head around the 3D CAD software to make another design. Each time we run the workshops we try and make small changes so that we’re constantly improving the format.

Just as I’m about to finish, it now really looks like it’s going to snow. It’s been threatening like this all morning, but now it’s getting very dark. Definitely a building day, although I might put my other micro quadcopter together and race it around the house later.