A Year of Autogyroing

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It was too hot again, but I wanted to fly the autogyro because this is the weekend a year ago when it flew for the first time. You can see just how hot it’s been the last few weeks from the picture above. The grass is dead and the ground is completely dried up and cracking. Anyway, as it happened there wasn’t enough wind to spin the autogyro’s rotors, so I didn’t risk a flight, although it was right on the cusp of being possible. I elected to take the safe option and go home with it in one piece rather than risk a flight. This time out I’ve removed the two washers behind the motor mount giving it left thrust and changed to give me one washer of down thrust instead. That’s washers top and bottom on the right side moved to left and right on the top. This is in response to the fact that I ended up with full left aileron trim and full down elevator trim last time it flew. Unfortunately, I never got to test the change, so it’ll have to wait until next time.

Back to today’s flying and there was already a guy flying a foam Cessna type trainer when I got there, plus the guy with the DJI Phantom from the other week and somebody else who brought a Hobbyzone UMX Corsair up on his electric bike. My first flight of the day was with his Corsair, but, launching left handed, my first throw went straight into the ground. I’m obviously getting too relaxed about flying these UMX aircraft, as they normally fly perfectly straight from my hand. I got the owner to throw it for me on the next launch, with almost exactly the same result. This aircraft has AS3X, so it’s supposed to be able to fly itself. The third flight worked out better and I got it into the air, but it was a wild little beast. There was much too much aileron movement – I knew that from before the first launch, but it was adjusted down mechanically as far as it would go and there was no way of changing it on the very basic transmitter. I found that I could fly it around, just coaxing it with the ailerons, but too much aileron input caused the nose to drop and it headed downwards fast. In getting used to flying it around, I tried to add a click of down elevator, then another, before the wing dropped again and I stuffed it into the long grass. There was no damage because of the cushioning effect of the long grass I was flying over, but I was a bit worried about finding it again, so didn’t take my eyes off of the point in the grass. It was easy to find in the end, nose down in the long grass with the dark blue tail sticking up in the air, not even having made it all the way down to the ground. It was just stuck in the top of the grass. We didn’t fly it again after that, but I would like to get it sorted out properly because the F4U Corsair looks absolutely fantastic in the air.

After that I had four flights with my RS352, plus a bit of messing around with the Autogyro when the wind looked like it was getting up. It was just teasing me, though, because as soon as I had the autogyro set up and ready to fly, the wind dropped to nothing. When I flew the RS352, the wind would get back up. I decided it wasn’t an autogyro friendly day, but then the RS352 wasn’t going all that well either. I don’t know whether the heat was causing a lot of turbulence, but they were odd flying conditions for what you would expect to be flat, calm.

We had one success story of the day, where the Italian guy who saw the previous flight of the Autogyro a few weeks ago managed to find his lost drone out in the long grass. I hate losing aircraft like that, so it was really good to see him get it back. All in all it was a very quiet day, with just the couple who fly the Mavic turning up near the end. They were the only ones left when I had to call it a day.

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Too Darn Hot

OK, the heat beat me this week. It’s 32 degrees in the shade and flying outside didn’t seem like a good idea. I’ve been getting all the stuff together for our next Drone Workshop in a couple of weeks time.

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I still need to find the flight controllers, additional frames, motors and props. Then everything has to be tested to make sure it’s all working. It sounds easy, but it all takes time.

In addition to this, I’ve got to the point where I’m beginning to write a simple flight controller for a BBC MicroBit. I may have run out of time on this because of other projects, but it will be useful just to be able to get something to lift and hover in a vaguely stable fashion.

It may be 30 degrees outside, but it’s about 40 in here working on a computer, so progress has all but come to a halt until the temperature drops. This heatwave can’t last much longer, surely?

Long Grass and Hot with Severe Turbulence

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The grass has grown a lot in the three weeks since I last flew. I didn’t take the autogyro this week, though, because I thought that there would be no wind with the heatwave we’re currently experiencing. That was wrong, but it was still good that I didn’t bring it because the 10 knot wind was much too strong for an autogyro that I’m still not confident flying. It did occur to me that today is the first of July and the first flight of the autogyro was on the 16th July, so it’s almost a year since it first flew and it’s still not completely sorted. It’s still a work in progress that, but today I flew the RS352.

When I got there this morning, there was already a guy with a racing drone at the far end of the field doing his level best to hit the tree he was sheltering under. Then another guy walked past me without saying anything and stopped about 20 metres away. What on earth is he doing?

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Oh, it’s a DJI Phantom that he’s setting up in amongst the long grass. After that we had another guy with a high wing foam Cessna, Parrot wing and Corsair (with broken retracts). He was joined by a new guy with his young son who had a blue Horizon Hobby high wing Cessna aircraft (possibly the Cessna 182?). I helped them out with the maiden flight, but I did sort of talk them into flying it despite the fact that it was very windy and they were wondering whether it was a good idea or not. That’s a bit strange because usually it’s the other way around. Newcomers don’t have any idea about weather and try to fly in terrible conditions, but I talk them out of it. Having flown more of these UMX planes than I can count, I was confident it would fly in the conditions and it certainly did. The little guy even had a go, but it was a bit of a handful in the conditions, even with the AS3X. When I looked at the elevator stick, he was holding in full down to stop it ballooning in the wind, plus he had the throttle backed off to about 40%. In ideal conditions, I think he would have flown it beautifully straight from the hand-launch. Anyway, he let me have a fly to see what the trim was like in the very windy conditions. I think it was fine, just needing a bit of right and some down, but it really wasn’t a day for trimming new models. He then took it back and he and his son had a go, which is when it started to go wrong. They let it get too far down wind with the power getting low and couldn’t turn it back into the wind to come home. I am annoyed with myself for letting them get into that situation, as, when I took the controller off of him, I couldn’t get it back on the low power either. All I could do was to circle, miss the trees and land in the long grass, all while the very small plane was at the extreme edge of the field. It all had a happy ending, though, as the plane was fine. There was no way I was going to lose their aircraft on the maiden flight. I was actually more worried about not being able to find it again in the long grass, but there it was just waiting for us to find it. So everybody goes away happy.

After that, we had another guy turn up with a racing drone that was exceptionally fast. In fact, frighteningly fast bearing in mind that he himself admitted that he wasn’t very good at flying it with FPV and kept crashing into the ground. It didn’t seem to work all that well either.

The other notable flight today was the Parrot Disco flying wing making a fully autonomous flight. At one point he thought he had lost it, because the radio and FPV dropped out, but it came back, circled around our heads and made a landing all by itself. Admittedly, it landed a long way off and might not have been so good if it wasn’t for the long grass cushioning the landing, but it was vaguely in the right place and it didn’t land on any of us.

As for me, I managed four flights with my RS352, where the first two I would call usual hot weather with a bit of wind, but for the final two flights the turbulence was extreme. I could hardly keep the plane in the air as it was that sort of turbulence that was always trying to push it down into the ground. I tried getting up higher out of the low level turbulence zone, but that didn’t help as it was yawing all over the place and dropping a wing while still trying to fly itself into the ground. I did some really ragged aerobatics, but that was about it. At least my landings were good, though. Despite the blustery wind, I still managed to hit my spot on the only 3 metre patch of mown grass four times out of four. Extreme wind landing techniques applied, i.e. come in fast and high on power and hover it in. It likes that better than trying to maintain forward momentum against a strong wind.

That’s it for this week, but I’m going to have to start thinking about drones again as I have National Robotics week to prepare for in three weeks’ time.

Football Sunday

I didn’t manage to get in any outdoors flying this week, partly due to work and partly due to a certain football match kicking off at 1pm. I would have needed to take the bike this week and with the temperatures over 30 degrees plus a damaged shoulder, it would have been quite difficult. At the moment I can’t even get the bike out of the shed, so carrying it over the bridge is impossible.

It’s getting dangerously close to national robotics week and my little flying robot is still a long way from flying. I had a look at the accelerometer data from it this week, but the numbers I’m getting back are very strange. This precipitated the move from microPython to the raw C++ using mBed, but I still don’t know what I’m going to get back yet and whether a BBC microbit has the necessary hardware to fly. It’s certainly got the power, but whether it can use that power in a controlled fashion is another matter entirely. The next week should provide the answers. That is if I can manage not to spend all my time working again.

Hopefully normal service will be resumed next week.

Fathers’ Day 2018

There’s no flying this week because the weather has gone all weird again. It’s been raining for the last couple of hours, then gone very windy. Never mind, though, as I’m snowed under with work again and haven’t done anything else this week.

Here’s a sneak preview of something I’ve been working on for a while:

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I’m not sure whether the BBC MicroBit’s magnetometer and accelerometer can be made to stabilise the quadcopter, but it’s certainly got enough power to lift. As something you can use to teach kids aerial robotics and programming on, it might be just the thing. It’s still very much a work in progress though.

Autogyro Flies!!!!!!

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The ATOM Autogyro flew again!

OK, so I had two attempts where it ran along the ground, jumped into the air, wanted to go vertical again and turned around to the left, heading back towards us before I managed to effect a landing (sort of). There was one other aborted take-off when I recognised that the head speed was too low as it was rolling left. Then after that a four minute flight. I didn’t realise until afterwards, but that is the first time it’s ever taken off from the ground. All the other flights have been hand launches.

My strategy this time was simple. Put it on the ground and wait for the wind to spin the rotors up to flying speed. Then apply throttle and run along the runway trying to make it hop into the air, then back down again. The reality was that the wind refused to blow when I wanted it and I stood there waiting for so long this morning that I clocked up 1h5m on my radio’s timer. I had several goes on and off while the wind did its thing, but I think the thrust line might be wrong based on the two near misses. The first time it ran along the runway, jumped into the air and immediately wanted to go vertical, apart from me adding a lot of down and backing the motor power off very quickly. Taking off from the ground rather than doing a hand launch meant that my fingers were already on the sticks as it lifted. This resulted in it turning around to the left and heading back towards us, but I just about managed to hit the ground softly enough for a second go. The next time the wind was favourable, the second attempt was largely the same as the first, but now I had the rotor head adjusted on the elevator trim to be much further forward. Also, it was noticeable that I could control it when the power was off, so the trick would seem to be not to use full throttle. When I had a third go, it sailed away and climbed into the air with me in control but under less power. What followed after that was a four minute flight where I nearly stuffed it into the ground on at least three occasions. It ended up with full left aileron trim and full down elevator. The height loss when you turn on the ailerons is huge, so I was adding in rudder in order to bring the nose around. I have to say that there were a lot of control inputs going in just to keep the thing in the air, but it is a very different type of aircraft to fly. What I need now is to be able to get it into the air consistently so that I can trim it to fly in a more stable manner. All in all, though, it was a good day and I’m very happy.

As for the rest of the morning, I also flew a UMX Beast for somebody else and absolutely loved it. The ailerons aren’t powerful enough as they had been turned right down, but it was very easy to fly in that trim. Loops were very nice. I only got one flight with my own RS352, though, because of all the autogyro testing. Other than that, we had a guy with a Parrot Flying wing (autonomous flight) and foam Cessna High Wing aircraft. Then another guy with a custom built F450 drone, another with a Mavic and a third with a DJI Phantom. The best aircraft belonged to the guy with the foam jet style aircraft, Eddie the eagle and a foam Vampire ducted fan. I love Vampires. You can just see it in the background of the image above, along with Eddie, who also looked great in the air.

Well, I’m happy. I flew the autogyro and it’s back in one piece, so I can make a few trimming changes before next time. Just for the record, the only difference between this and the last flight was the addition of the extra shim under the blades to give a more negative angle (and less lift). I’ll look at the thrust angle next and do a re-check on the balance point (hang angle) just to make sure. I’ve also got some video footage of the flight, so that might get posted once I’ve done some editing.

The Autogyro Wind Blew Too Late

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I took the autogyro out this morning, but there was absolutely no wind first thing, so I ended up not being able to fly it. If the breath of wind there was at the end of the session had been there at the beginning, then it would have been perfect. There wasn’t enough wind to spin the rotors until late on and rushing a quick test flight when I was pushed for time didn’t seem like a sensible idea, so the autogyro went home in one piece.

I spent all yesterday going through the autogyro’s systems to make sure everything was spot on. One difference between this setup and last time is the addition of the extra shims under the blade roots, so the blades are at a more negative angle to the head plate rotation plane. Also, while reading the original RCM&E article, I noticed that the designer put a 1 degree left side thrust angle on the motor using washers. I didn’t have this two weeks ago, but I can’t remember if the successful flights last year had it in or whether I decided to remove it? I added the left side thrust this time just as a precaution, as it won’t make a huge difference. The balance, measured using the “hang angle” technique, will make a big difference, as will the head plate angle (elevator), so this is what I spent most of the time checking. I actually had full down elevator trim on the radio, so I adjusted the mechanical linkages and moved this back to zero on the radio to give myself some margin for adjustment.

My plan for flying was simple. I was going to sit the aircraft on the runway and pull the elevator fully back to tilt the head back and let the wind spin the rotors up. Then I was going to release the elevator and try moving forwards slowly with the rotors spinning to try and “hop” like they suggest when trimming an autogyro. The idea is to fine tune the head angle so you can add a little speed and slight back tilt for it to gracefully take to the air. It was a disappointment not to be able to fly it.

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I managed three flights with the RS352, which sustained some damage on the journey to the field. The flight box moved and took a bite out of the right aileron, but nothing that a smear of PVA won’t fix. It flew cuban eights well in the completely still, hot, air. We don’t get these conditions very often and it was very busy at the field this morning. I saw the guy whose Hurricane I flew ages ago, with a foam drone and a Multiplex Easy Star, which I seemed to keep finding in the same bit of air as me. We also had three or four hand launch gliders, a pure bungee launch one, the high wing Cessna type trainer from the other week and a few drones, but they like to keep to the limits of the field and refuse to talk to us gyronuts.

There’s not much else to say, except that it was so hot I think I’m starting to melt. This afternoon I need to make a brushed motor controller for a micro drone, which means I’m soldering in the heat. If it works, then I’ve got an interesting aerial robotics test bed to play with.

Oh, well, I’m disappointed not to fly the autogyro, but that was the sensible option and it gets to fly another day. Let’s hope next week’s weather is better.

Autogyro Repair, the Sequel

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Well, true to my word, I repaired the autogyro back to flight ready status in a week. Unfortunately, the weather conspired against me. We had violent electrical storms the night before and forecasts of storms the next morning. Although it did rain quite hard, I’m not sure that the storms every really developed, but one place I don’t want to be is standing in the middle of a field holding a radio transmitter when there’s electrical activity overhead.

As for the repair, I stuck the spruce longerons back together again.

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Then the fuselage sides got glued back together where the LiPo had moved forwards in the crash and separated them. You can just see in the picture below that I’ve also had to add a plywood plate where the spruce longerons meet the red fuselage. It’s just visible on the right of the picture and, if you compare to the area with the sellotape in the picture above, you should be able to make out the new 2mm plywood strengthening plates.

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I’m a bit worried about making this area too strong, as it will eventually just break at the point where the spruce meets the fuselage. After that, I’ll be trying to dig the longerons out of the fuselage to replace them as they extend right up to the rear former.

Apart from sticking Pete the pilot’s head back on, the only thing left was the motor.

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I probably could have bought a replacement shaft for the motor, but I chose to make my own out of a piece of 3.2mm rod.

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You can see my new motor shaft at the bottom of the picture. It’s not quite perfect like the machined original above, but I made it and I like it better. Actually, it made me wonder what the commercial motor shafts are made from, as the original was obviously designed to fail rather than bend the motor bell in an impact. That didn’t exactly work and a shaft costs £3 while a brand new motor costs £10. My solid steel shaft is a lot stronger than the original, so one more hit on the ground like before and it’s going to be a new motor. I can live with that.

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So there we are, one fixed autogryo and I’ve now got a whole week to properly test that everything works before committing it to the air again. Next time out I’m going to increase the shim under the rear of the blades to 0.8mm, which should reduce the lift and help with the launch.

That’s it for this week, but I did video the autogyro’s reconstruction last night, so I might post that later depending on how it came out. Let’s hope the conditions next week are more conducive to autogyroing.

Autogyrotations

I flew the autogyro again today for the first time since its crash in October. It didn’t go so well.

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These are the before shots. I actually liked the previous all blue colour scheme better, but this one looks more like the RCM&E review model in its red, white and blue.

I was a bit worried that there wasn’t enough wind to turn the rotors for a hand launch, but there was plenty to get up to flying speed. The problem stemmed from the launch, as I’ve damaged my right shoulder and had to hand launch left handed for the first time. Looking at the launch video, it’s not so much a left handed problem as a consciously not throwing it forward too fast problem. The YouTube clips I’ve seen of autogyro hand launches show a gentle push with the arm at 45 degrees tilting the rotor disk to get it to spin up, followed by a slow transition from 45 degrees to level with the horizon and a push forwards. I was worried that my previous launches were more javelin style aircraft launches, in other words, get as much forward speed as possible. This isn’t necessary with an autogyro, as the speed is in the rotor disk. You do have to throw it flat and with some forward speed, which I didn’t do well enough.

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This is a fraction of a second after launch. This isn’t going to end well.

So, a fraction of a second after launch, I had an autogyro prop hanging in a vertical manoeuvre. All I could really do was try and stabilise it laterally, allow it to climb as much as possible and try to flip it around in a stall turn. Another five feet and I would have done it, but it ended with a fairly soft impact directly on the nose.

Spy satellite pictures show more of the descent back to Earth:

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OK, so I had a RunCam filming the hand launch and the images above are from a GoPro Hero 4 Session dug into the grass pointing skywards to the left. I wish I had captured more of the short flight, as you can see what I mean by “stabilisation problems”. I’m not just prop hanging, the head is pointing ground-wards at an alarming angle.

 

The damage isn’t too bad considering. Like I said earlier, I had it stabilised by the point of impact, I just needed more height to fly. It’s snapped the motor shaft, split the fuselage where the LiPo moved forwards and snapped the two spruce tail sticks. I am determined to fix this quickly and get it back in the air next week.

This is the most difficult damage to fix, as it’s right up at the point where the spruce longeron meets the fuselage. I’ll have to have a think about this.

 

 

The split fuselage is easy to fix:

 

Oh, and I nearly forgot, Pete the Pilot isn’t feeling too well:

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It must have been that negative g manoeuvre that I pulled.

So, that was the autogyro. I also had three flights with the RS352. There was one other guy with a high wing foam aircraft practising his touch and goes, the lady with the drones and a couple of guys with some really cool HLG gliders.

OK, where did I put that book on how to fix autogyros for the stupid and impatient?