Author: rwmilton

Life and Brian

We’ve got the tail end of a Winter storm called Brian this weekend, which has brought with it winds of 50 mph, so flying isn’t possible. I’ve been fixing my ATOM autogyro this week and looking at the video footage from last week’s crash.

Atom away! This is from the video of last week’s launch before things went wrong 26 seconds later. I’m not sure what’s happened with the white spots on the image, but they were both fine before I transferred the images to a Linux machine to upload to the blog.

These rather blurred images are blown up frames from the video as it wasn’t much more than a dot on the screen when the rotor failed. The image on the left shows it flying left to right normally. You can just about make out the tail (bottom left dark blur), fuselage (bottom right) and rotor (top). The image on the right is just after the point of failure when the rotor blades folded up. It’s still moving left to right, but has now pitched up about 45 degrees. The lowest point on the image is the tail (8 o’clock position), with the boom and fuselage visible, then the mast pointing up at 11 o’clock. It just fell to earth from there.

Now that I’ve had a chance to examine the wreckage in more detail, I would say that I was quite lucky with the impact. All it’s actually done is to snap off the nose, break the two booms and do some other superficial damage.

 

Looking at the bits, I think the point of impact was on the right hand side of the nose. That’s with the fuselage rolled 90 degrees right when the ground jumped up and prevented it falling any further. Neither the prop, motor nor undercarriage are damaged, ruling out a direct nose in impact and a wheels hitting first impact. The right side of the fuselage nose seems to have taken the most force and judging from the way it broke, I can see how it snapped. The LiPo exited via the left side of the nose and you can see the evidence of where this happened. I’m assuming that the tail then followed the broken nose into the ground, splitting the spruce 6mm square longerons, but doing very little damage to the fins.

Now, on to the repair and I had already set and glued the spruce tail sticks back together during the week. I used epoxy resin, fitting the split ends back together quite easily and binding them with tape and G clamps in a frame I rigged up to ensure I got everything square. The tape allows me to get some force on the wood to pull it back into shape to then put the clamps on without sticking everything up with glue. Once the glue has set, it can be removed as the epoxy won’t stick to it.

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After that I set about the fragmented nose section. In the end I decided to graft a new 6mm base section on the existing fuselage, along with some new front side sections. The ply firewall is unrecoverable, so I made a new one, but was able to salvage the ply plate for the undercarriage and the internal ply plate. The front section of the nose is a sandwich of multiple sections, which makes for a very strong construction, but complicates the process of repair. I traced the drawings off of the original plan, cut them out and used them as templates for the new pieces.

 

That’s my new base and ply firewall ready to be glued in place. Now all I need are the fuselage side pieces to graft in. I do find repairing aircraft a very satisfying experience.

That’s all for now, more to follow later.

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Autogyro Days

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I wasn’t really planning on flying this week, but the forecast was for good weather with a 10mph breeze and I had finished the modifications to the autogyro’s blades. The shims are a little bit more than the only successful flight so far, so about 1mm where they were 0.8mm before. I was determined to test the autogyro again, but things didn’t work out exactly as planned.

I was the first one there this morning, closely followed by a UMX Super Cub with ailerons, flaps and AS3X stabilisation. This was my first flight of the morning, as I flew it for the owner in the very blustery conditions. It flew beautifully, with me pointing out from the launch that I wasn’t actually doing anything. It knew how to fly all on its own, which is impressive for something that’s not much over 30g in what was by now really turbulent windy conditions. After that another old friend who I haven’t seen in months turned up with his Multiplex Xeno flying wing. We had another guy who test flew his first aircraft the day before and showed us the evidence on his phone. It was a low wing stubby sort of a plane, which looked a bit like a lazy bee, but surely wasn’t suitable for beginners? We saw it roll along the ground, roll and yaw left, clip the left wing on the ground and turn over. It looked OK, but none of us fancied flying it. He said he’d be back next week, so that should be interesting. Other than that, we had a professional drone pilot who wanted to keep his flying hours up on a Mavic and a couple of kids towards the end of the morning who looked like they didn’t know how to fly a DJI Phantom.

OK, so after the Cub, I flew the Atom Autogyro. To cut a long story short, it crashed 26 seconds after a really successful hand launch. I have the video of the launch, plus my friend also filmed it on his phone. On my video, which was using the wide-angle runcam, you can just see the start of the crash, but it’s too far to really see and then the actual plummet to earth and crash is out of the frame. What I think happened was that one of the main rotor blades struck the prop, shearing the end off of the rotor blade and stopping the main rotor from spinning. From my point of view, it was a perfect launch, it drifted left a bit, gained height well, I turned right, went across in front of myself with the wind blowing in my face, got to the right hand edge of the box I was flying, went to turn right again to come back and something flew up from the rotor disk. I assumed a blade had snapped, but was then aware that the rotors had all folded themselves up and were no longer spinning. At this point I put the thrust to zero and realised that there was nothing I could do as the aerodynamic control is all through the rotor head. No spinning head, no control. The fuselage was heading towards the earth at a 45 degree angle and there’s no lifting surface, so it’s like when the wing bands break and the fuselage spears into the ground on its own like a javelin. Admittedly, I still had rudder and throttle control, but I can’t see that using the rudder to roll to a higher drag orientation would do less damage. I figured that 45 degrees into the ground with the nose and wheels taking the impact is the best option.

On inspection of the damage, it was evident that 11cm of the tip of one of the blades was missing. It had landed a long way from the main wreckage, so this was obviously what I had seen flying up off the aircraft in the air. We thought that the tail was the likely source of the impact, but there is a gauge out of the spruce leading edge of the blade and score marks which suggest a more violent impact.

 

 

The vertical fins are also fairly intact, although the impact with the ground has broken both of the spruce tail spars. The wheels have sheared off most of the front section, along with the motor and firewall. That will need replacing and strengthening with ply. Pete the pilot has also been decapitated, but he’s easy to stick back together. I might even give him some better goggles while I’m at it. So, basically, it should fly again, but the damage is quite extensive.

 

After the autogyro crash, I had three flights with the RS352. One of my four batteries has definitely had it, so I’m going to have to retire it after just under two years of use. Although I’ve flown the RS352 in some really bad weather conditions, it was surprisingly bumpy in the air today. On the first flight I actually switched out my flaps and flew without the extra camber, going a lot faster, but with down trim. My flying was really ragged today, or maybe it was just the conditions? I suspect the wind may have played a part in the autogyro crash, because, even with my usual aerobatic aircraft, it was a real handful today. It might be something to do with being right on the edge of ex-hurricane Ophelia, which we’re going to get the tail end of tonight.

Oh, well, I’ve got some building to do now.

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That’s the Xeno on the left (very small) and a bird on the right.

Autumnal Sunshine

It was quite a pleasant morning this week, despite a big black cloud making an appearance around 11 o’clock. Once that had gone it was back to warm and sunny.

It was really busy this week as there was one guy half way across the field flying a Phantom when I got there, plus another drone flier in the middle. As I was walking across, I did say to him that he could hang out with us in the middle, but he didn’t seem interested. After that we had the red UMX Taylorcraft arrive by bike, newly fixed from the time he took it out in the bag without any protection and broke it. My first two flights of the day were with this Ares Taylorcraft, which needed progressively more left rudder added as the flight went on. The power system was also a bit of an issue, but those 1 cell LiPos are always a bit variable. The aircraft is rudder/elevator only and I think the crease in the rudder was causing the control problems. It was perfectly flyable, but initially wanted to keep turning right. Left trim counteracted this, but if you slowed it right down, it would start turning right more as the speed decreased. On the second flight, the rudder had been straightened a bit more, so the trim was completely off again. It’s not all that agile anyway, so left and right trim changes aren’t that big a deal, but I did feel as though I was trimming a free flight model, given that it was sunny with very little wind.

After that, we had another guy with a Mavic and a 250 size racing drone. Then two people with the Skysurfer that I flew the other week and a new Blaze high wing “warmliner” type of aircraft. The Skysurfer had a bit of an adventure, hitting the ground hard on the first hand launch, but then climbing away safely. Later on, we all heard the thump as it hit the ground hard on landing, but it was still OK, so they obviously build those things of strong stuff. The next pair to arrive had a small helicopter, a drone and a Bixler, which is another Syksurfer clone. The Mavic had fun chasing the Bixler around for a while. Finally, just as I was leaving we had the guy who usually flies the Stryker F27, but this time he had a Rare Bear Reno racer Bearcat foam model. I never got to see it fly as I was out of time by then.

As for me, I had three flights of the RS352. That was two good flights with the new(ish) LiPo packs, then I was about to launch on flight three – and by this I mean actually going through the motion of pushing it forwards into the air – when the revs started to drop off. I think this older LiPo pack has either had it completely, or it just hadn’t charged properly. Either way, both of these older packs are badly puffed up. Flight number three was with the second of these older packs, which was more or less OK, apart from not having as much power as normal. The flight lasted 6 minutes exactly, at which point the BEC cut and I landed. Normally I would land before that point, but obviously the capacity is a bit down on normal. My charging regime for this week is to store the LiPos at 3.83v during the week, take them up to 4.0v on Saturday evening and then fully charge right before flying on the Sunday. This seemed to work a lot better than fully charging on Saturday as I had a lot more power available.

There was no autogyro this week, as the forecast was for almost no wind and I’ve still got to make some modifications to the rotor blades to try and increase the lift before I take it out again. Hopefully I’ll get the time to do some testing this week, but, as ever, work keeps getting in the way.

One final strange thing happened this week. There was a black van turned up, like a black transit, but probably a people carrier taxi type of thing? Then, at about 200m distance, it looked like they were getting a whole load of bubble wrap out of the sliding door on the side. As this came towards us, the bubble wrap was actually a bride in a white wedding dress with the rest of the wedding party. I don’t know whether it was a real wedding or a photo-shoot, but they wanted to photograph the bride and groom next to some deer. That’s never happened before.

Wet and Windy October

It looks like last week’s prediction about the last days of Summer have come true. This week we’re looking at the tail end of a hurricane, so it’s windy with occasional bursts of rain. The forecast is for it to get worse as the day goes on, so no flying this week.

After last week’s flight with the autogyro, I spent some time doing a bit more research into autogyro aerodynamics. This thread on RC groups is very good:

https://www.rcgroups.com/forums/showthread.php?614030-Gyrocopter-Aerodynamics

It explains that, because of the rotation of the blades and the lag between where the asymmetric left from the advancing and retreating blades takes effect, insufficient rotor speed will result in a pitch up moment. Only in the case where the blades are held rigidly to the hub will there be a less than 90 degree lag and an additional left roll component. Now, I’m not sure I agree completely with all of this, for two simple reasons: firstly, the ATOM has three blades and secondly, I’ve witnessed a violent left roll first hand, which was the cause of the crash. It does, however, give a much more solid scientific basis for the analysis of how the autogyro flies. Also, when I looked at all the video of my autogyro launches, there is a very definite pitch up exactly as predicted, but coupled with a left roll. This all points to insufficient rotor speed, but I still can’t figure out what the underlying reason is.

What I need to do now is a bit more research and modelling of how the autogyro flies. In the course of this Internet search, I found the following document:

The aerodynamic analysis of the gyroplane rotating-wing system (Wheatley, NASA, 1945)

I need to go through this in a bit more detail, as it gives a basic outline of all the forces and moments involved. The references at the end also give some links to other publications which I can follow, plus the same author has a number of other publications held on the NASA archive. This is what I need to make an autogyro flight simulator.

However, this won’t explain what’s wrong with my ATOM. My best guess at the moment is that the launch is tending to put it into a stalled part of the flight envelope, from which I can’t recover because of having no height. I say “tending to”, because the real puzzle is the single 4 minute flight I had a few weeks ago when everything was working perfectly. I’ve taken the trim from what I had in the air then, hence when I look at the head now, it’s tilted over to the left which was to counter-act the right roll I was experiencing in the air. My tests now are going to focus on the power system, just to convince myself that the speed controller and motor are all working properly, and then the head forward angle and blade shims.

 

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.

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.

The End of August

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My RS352, captured using the high dynamic range (HDR) setting on my Nexus 4.

I’m sad this week because I haven’t got my Autogyro to fly. Never mind, though, because it’s Bank Holiday weekend, so I’ve got the whole of tomorrow to do the repairs. All I need to do is to epoxy the spruce 6mm square longeron where it’s split on the right tail, add some ply reinforcement and cyano the right fin back on. Fairly minor really, but I just didn’t get time during the week.

As for this week, the weather was just about perfect again. There was already somebody flying a drone at the edge of the field when I arrived, plus another guy flying a Blanik way down the main path. I’m not sure if it was a glider, even though I saw it flying and said hello to him as he was walking past me back to his car.

Anyway, soon after that we had one father and son with a foam board F18 and a new Hobby King Prime Jet Pro. Both flew really well, but the F18 had rather an untimely end. The wing disintegrated in mid air and it crashed, with parts of the wing debris floating down into a tree. The fuselage didn’t have a bad crash considering, and all the gear was salvageable. We also had another father and son, this time with a fairly new SIG Kobra that they had flown for the first time the day before. He was still a bit nervous landing it, so I ended up standing next to him and talking him down on the first approach. Later in the morning, and after he had had a few flights with it, things got a little bit interesting. He took off and the telemetry told him that the flight battery was low and he needed to bring it back in quickly. Luckily, I hadn’t quite launched my RS352, when he asked me to land the Kobra, so I could put my plane on the ground, pull the power connector out and take the Taranis transmitter off of him to fly the Kobra. OK, so I’ve never flown this aircraft before. I flew across in front of myself and started a slow left turn upwind, thinking that I would fly downwind, turn onto final approach and land. I didn’t even get that far, because I could feel the power going half way around that first turn, so the best option was to complete the turn so that the plane was pointing directly towards me and land with the wind. Trying to manoeuvre, even a fairly lightly loaded pattern ship, as the speed and height are both reducing is never a good option, so the first turn I had made with this aircraft was going to have to be the final approach run. It all worked out well in the end and I managed what I called a reasonable landing with the wind in rough grass. The undercarriage survived unscathed and I didn’t damage anything, so mission accomplished. I actually wouldn’t mind one of these myself, as it looked like a very nice aircraft.

We had a few more visitors this morning, with the Sky Surfer from last week, but he had also brought his UMX Tupolev WW1 biplane. I still can’t work out precisely what aircraft this is, so I’ll have to do some more background research. It’s brown and had a penguin roundel (yes, really). Bringing WW1 back to life, we also had a red UMX Fokker DR1 triplane (quadriplane), which I first flew for the owner a few weeks back. Two of us had a go with it today, but it just didn’t have the power it had before and refused to fly. Eventually I worked out that the problem was where the engine cowl had been glued back on and it was now rubbing on the prop and obviously losing thrust. Despite my best advice to take it home and fix it, the owner wanted to see it fly, so he borrowed my scalpel to try and prise the depron cowling away. This didn’t go well, as it turns out that inside the top centre point of the cowl there is a beam and electronics board carrying the rudder and elevator servo. I was worried about cutting motor wires and it turns out that the radio, speed controller and servos are all housed in the engine bay. To cut a long story short, we had cut one of the wires to the elevator servo and destroyed the beam that the servos and electronics were mounted on. In other words, both servos were now no longer attached by anything other than the push rods. I felt really bad about that, but I had told him to take it home and fix it as these types of aircraft always require micro surgery.

In addition to this, we also had the lady on the scooter with her tiny drone, then a family with two kids and another toy drone, two people who I haven’t seen before with a Bixler and a drone (Mavic?), another guy with a DJI Phantom in a holdall, the professional drone pilot with his DJI Inspire keeping his flying hours up and another couple who I’ve seen a lot with a DJI Mavic. Yes, it was rather busy towards lunch time.

As for my flying, I got in four flights with the RS352, which was strange as it was quite a long way out of trim. My first thought was that the trim I had from the ATOM last week was applying when the model was set to RS352. My radio is a Futaba Field Force 8, and that’s not how it works as I checked after the first flight. It’s odd, but I had a lot of right aileron trim (about 10 clicks), most of which got taken out as the flights progressed. I can’t really explain that, but I still had four good flights.

I also got to fly the Sky Surfer as it’s owner was having problems with hand launching it himself. He threw it a couple of times with me flying it and I gave him the controller once it was in the air. I flew the DR1 a few times until I figured out what was wrong with it and I also flew the SIG Kobra, even if it was only briefly. All in all it was quite an eventful morning.

Right, I’ve got the rest of today and the whole of Monday left, so I’m going to fix my autogyro.

Autogyro Flies!

After starting the build in Autumn 2014, I can finally say that I’ve fulfilled my ambition to fly my own autogyro. It didn’t all go completely to plan, though.

Last night I added a bit of extra shim to the blades to help with the spin up:

IMG_20170820_100458.jpg

 

LiPos charged, I was ready for the first flight of the day, so, here we go again…

 

I decided to use the wind to spin up the rotors and then hand launch, which worked last week when I got my first 10 second flight. This week it was a bit windier at around 8mph, which I figured was perfect. This time I had the trims zeroed, so the head head was at 90 degrees to the mast, which is the recommended position. I tipped the aircraft back so that the nose was vertical, the blades spun up to a speed where there was a definite “lifting noise” from them, increased the throttle and rotated to the horizontal launch position and released the aircraft into the air. Immediately it wanted to go backwards and I spent most of the 20 second flight with the elevator stick all the way forwards trying to control it. Anyway, the landing wasn’t too bad, in long grass over to my left and downwind. On recovering and checking the aircraft, I discovered that the right fin had snapped in the landing.

 

I borrowed some cyano and patched it up with sellotape, then I moved the elevator trim all the way forwards and gave it another launch. I had a four minute flight with it this time, flying backwards and forwards in front of myself, demonstrating some semblance of control.  This time I was actually flying it, even if it was a bit of a handful to start off with. The thing is, it was pulling badly to the right, so I spent the first few minutes gently dabbing in a couple of clicks of left aileron trim until it was flying more comfortably. That’s 25 clicks of left and about the same on the down elevator prior to flight, which explains my earlier comment of, “a bit of a handful”. Especially when you’ve never flown an autogyro before, and it is a very odd thing to fly. Also going through my mind was the fact that the fin was held on with sellotape. That’s why I was very reluctant to use the rudder, but I did  give it a go near the end of the flight.

As for the flying, the elevator controls the speed, while the throttle controls the height. I did actually get up quite high at one point, but I was very careful not to let it get too far away from me as the orientation is a problem. I had a couple of moments when it was turning towards me and I lost orientation. What really surprised me was how much height I was losing on the turns. I was flying off to my left, turning 180 degrees, losing half my height, then picking the height back up again as I flew in front of myself, only to lose it again on the turn at the right hand side of the box I was flying in. It didn’t seem to matter if I turned left or right, the height loss was the same, and there were a few points where I couldn’t turn tight enough to fly in front and had to do a big circular circuit around my head. There didn’t seem to be much authority in the turns, but I can live with slow and docile at this point. Like I said before, I did very gingerly try the rudder out at one point and it was effective in bringing the nose around, but I was too scared of the cyano and tape on the fin giving way to do very much. Anyway, that was the battery exhausted, so I had to think about landing. This proved to be very easy and I touched down with almost zero speed and so lightly I’m sure my pilot in the red baseball cap never even realised. The only thing to mention here is that it’s very important not to reduce the speed too much. I was on the point of doing this and could feel it rolling left as the speed was decreasing. Post flight analysis of the battery showed that it only had 10% left.

Four minutes of autogyro flight! I’m only saying that again because it goes a bit downhill after that. On the next flight, the launch was fine, but it just didn’t seem to have any power. I can’t understand it because I did two launches, and both times it didn’t want to climb, landing about 20 seconds later. On both occasions, there was ample power when the aircraft was recovered. I decided to charge up one of the new 1300mAh packs and see what difference that made, but I’m fairly sure I made a mistake launching. There wasn’t enough speed in the rotor when I released it, the aircraft went away, but climbed too fast and rolled to the left. It was like it did a stall turn from my hand and I almost managed to recover it, but it hit the grass quite hard on the two wheels and tail skid simultaneously. This had the effect of partially splitting one of the spruce longerons and put paid to any more flying.

 

I always suspected that a hard landing would cause a break like this, but it’s easily fixed with some glue and a couple of plywood doublers. In my defence, I think the rotors were spinning at the right speed, right up until the point where it left my hand. The wind dropped at just the wrong moment, causing the rotor speed to drop as I brought the aircraft up to the horizontal and applied throttle.

Anyway, I’m very happy now that I’ve achieved my lifelong ambition to fly an autogyro, so I’ll fix it up and have another go soon. Oh, and by the way, there should be video of the event, assuming the camera worked. I haven’t had time to look yet. Post-flight analysis of the flights were there was no power could be interesting. I’m wondering whether I was pulling back on the elevator more than I realised, rather than giving it throttle? I really don’t know, as I definitely had 100% throttle and had to back off to land. Would forward tilt have increased the speed and built up lift? What I would really like is some sort of telemetry to record my transmitter inputs along with the flight video.

As for the rest of the day, I had a single flight of my RS352 right after the final flight with the autogyro. I buzzed around the sky with an old Corsair, which was a lot of fun. We were dogfighting with each other, but pretending that we weren’t. Him and his father between them had a fair few aircraft, including a Lazy Bee and a UMX Beast, which I’ve flown before and which he threw around the sky very convincingly. There was another guy who helped me with the autogyro last week, but this time he had brought his son and was teaching him to fly with a buddy box. I haven’t seen that for a long time, but together they were flying a Bixler. I also discovered that the aircraft I maidened last week wasn’t a Bixler, but actually a SkySurfer. The same guy was here again this week, but with his Nieuport biplane this time. Unfortunately, the Nieuport had a bit of an incident on its first take-off, then got into the air, completely out of trim, gradually settled down into flying, but suffered another incident on its second flight. This time it looked like the top wing was damaged, so he went back to his car and brought back a contra-rotating helicopter. This also flew, but it looked like the wind wasn’t its thing. When I had to leave at the end of the session, I left him with my sellotape fixing something on it. We also had a lady with a micro drone, brushless, and made from carbon fibre. I think I last saw her on the autogyro’s first outing a few weeks ago, but a couple of her friends also turned up with drones. There were also another couple of drones at the opposite ends of the field not wanting to talk to us (I wonder what they made of an autogyro flying past?). Finally, the guy with the Bixler also had an own design, small, agile, high wing plane that he spent the best part of a decade building. He asked me to have a fly of it and see what I thought. Well, it’s actually very nice to fly. I thought it was going to be very sensitive to roll, but actually, the controls were very well balanced. It was fast, agile and aerobatic, without being overly so. Anyway, he’s got a SIG Cobra pattern ship type plane that he’s just finished and wants to fly next week.

That’s about all there is for this week, except that I’ve still got the video of the autogyro flight to have a look at and edit, plus some repair work to do. I’m still determined to make the autogyro a regular flier.