Month: January 2017

Waiting for Rain

It’s dull and grey this morning, with a weather forecast that’s predicting rain at 11am, getting heavier as the day goes on. No flying this week then, so I’ve posted the video I took last week of my new 50g quadcopter’s first outdoor flight. The effect of the Sun and the mist is just fantastic.

In case you’re wondering, this is what I’m flying:

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We’ll ignore the bit at the end where I crashed it into the ground, but the throttle wasn’t picking up the thrust fast enough and the LiPo had gone by this point. The PIDs need a bit of work too, but this is still a work in progress. This one is using the HubSan 55mm blades, and I’m also going to test with some 75mm blades once I make a bigger frame. The general idea was to see how easy it is to manufacture a custom frame with everyday components and without using an expensive 3D printer. I’ve just cut out the blue acrylic using scissors and used it to sandwich some Depron. My only sticking point at the moment is how to hold the motors on. The one above is a friction fit in a bit of old plastic tube, but this requires a lot of skill and effort to make. My next evolution is going to use a slit cut into the tube so the radius can open and grip the motors without having to get the diameter exactly right. This also means using half round cups at the ends of the frame where the motor holders will be glued in. This might be too fragile, so I’ll have to see how it comes out.

I’m a bit tied up with work this week, so the only other thing I’ve done is to fix the prop adapter on my RS352. Here’s hoping for sunny and frosty next weekend instead of dull and rainy.

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First Flight 2017

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The weather was perfect this morning and, even though I thought it was going to be absolutely Arctic outside, the Sun made it really rather pleasant. You can see from the photo above that it was frosty when I arrived. There was already one person there, but, as these drone pilots seem to do, he was keeping to himself away from the part of the field where we normally fly from. I think he was flying a Mavic?

My first flight of 2017 was actually with the little blue quadcopter that I made last week. This was its first flight outside and it all went fairly well. I filmed it with the RunCam perched on the bin, so I’ll upload the video once I get a chance to edit it.

I’m a bit concerned that I’m pushing the LiPo too far in the 50g quadcopter, but the video shows a 3 minute flight from a battery that wasn’t full charged. I’m using a 1S 400mAh pack and it came off at 3.78v which should be fine. It’s just puffed slightly, as have all the cheaper LiPos that we bought. I just think that the KeenStone ones that we bought for about a pound each aren’t very good. They are very cheap though, but I still want to see if I can reduce the aircraft’s weight some more.

I also had a play around with the RunCam while I was flying the RS352, so I managed to get some video of me flying. In order to do this I had to fly one handed, though, and the transmitter was moving about, so you’ll have to excuse the camera work and the piloting. Again, I’ll upload it once I can edit it.

As for the first test flight of the RS352 with its four new EMax ES08MA II servos, I would like to say that it was uneventful, but the prop wouldn’t stay on the motor shaft. I went to launch and the prop came off with the adapter. I tried screwing it back tighter, but I think the cold weather had made everything contract. After a lot of fiddling around, I managed to bodge a fix by lining the cone with a bit of insulation tape. Normally I would use sellotape as it’s thinner, but I didn’t have any and I also didn’t have anything to cut the tape with in the freezing cold. I just about managed to rip some off and make it all work.

OK, so once I had a prop that would stay on, the first flight was a bit of a non-event. Three clicks up and three clicks of left aileron and that was it. I tried a few gentle loops and rolls, but I wasn’t going to move the throttle more than I had to because of the prop issue. After that I had another three flights, but on the fourth the prop came off again as I was about to launch. I just about managed another fix and got it into the air again, but, a couple of minutes in, the prop noise changed ever so slightly and I elected to land. This was a good decision as the prop came off in my hand when I gave it a tug. You could see how it was a finger’s width forward from the motor where it should have been a tight fit. I’ll fix this before next week.

I had thought I was going to be on my own all morning, but, round about 12 o’clock, another guy turned up with his Corsair and what looked like a brand new UMX A10 Warthog. There was also the DJI Mavic from the other week, but before either of them arrived, the Spanish family with the free flight glider got some flights in. This was a lot of fun as they now had a tow line, which is something I haven’t seen done in a long time. It flew absolutely beautifully.

There’s going to be a video here once it finally uploads. Currently waiting for BT for the last 90 minutes…

Rain, Sleet, Snow

We’ve had all three forms of precipitation in the last few days. There’s been heavy rain since 6 o’clock this morning and we might get sleet and snow later, so it’s fairly obvious that there’s not going to be any flying done this week. I haven’t flown the RS352 since the week before Christmas now. My BMFA renewal arrived earlier this week, so I’m good to fly for the whole of the rest of the year. It’s always like this every January.

The little blue acrylic quadcopter is flying around indoors nicely though. You can see that I have added some basic prop guards since last week. I’m actually a bit disappointed with the weight as it’s come out at 48g flying weight, while I was hoping for a bit lower. I’ve still got to add the 4g FPV camera, but the test flight this morning was around 5 minutes. That suggests that it’s round about the same as the HubSan X4C, although the flight controller is in a different league. The separate flight controller and FrSky receiver that you can see in the picture above must be heavier than one of the integrated units, so I must be giving away a few grammes there. I’m flying it with my Futaba Field Force 8 which has a FrSky ACCST module in the back. This is what makes me really mad about FrSky, because I can’t use the Taranis radio with this receiver. Our Taranis for work was flashed with the European firmware and that won’t talk to an 8 channel receiver, so I’m sticking with the Futaba. Either that or we’ll have to switch everything back to the US firmware.

Anyway, it was refreshing to fly a quadcopter that I’ve actually designed and built myself. It’s just a bit too much of a conventional design, though, so I might have a go at some more radical alterations next. As for this morning’s first full test flight, I took some video using my RunCam, but it’s not that good, so I’ll have to try another flight later today. Also, I don’t think it’s calibrated properly as it was trying to yaw left all the time. This might be to do with the fact that I hold the flight controller on with double sided tape and the flight controller has a habit of peeling itself off where the components on the back don’t make a flat surface. It needs a better solution really, but it’s so easy and light to hold the flight controller and battery on with tape.

As for the balancing of the autogyro blades last week, that turned out to be harder than I thought. There is only a few grammes difference between the heaviest blade and the lightest, but glue doesn’t add that much weight, so it’s hard to get them to balance. I’m not sure how close they need to be, so I ended up trying to take some wood off of the heavier one, but they’re still coming out as 19.2g, 19.4g and 19.9g. That’s within 0.7g, so it’s probably close enough. When I finally cover them with film it’s going to cause the same balance problems all over again.

That’s it for this week, except to say that I now know how to make the Taranis work as a joystick with our flight simulator. You can reprogram the ranges to match the ranges that Unity expects, so it is perfectly possible to use it as a joystick in other software that was written in Unity too. FPV Freerider is one which immediately springs to mind. So that’s my afternoon planned out: film acrylic blue flying, add the FPV camera, play with Taranis and flight simulator.

Let’s hope it’s not raining next week.

Nuisance Drizzle

I’ve replaced all four servos in my RS352, so I really wanted to do a test flight this week. The weather forecast showed that it was always going to be marginal with fog and drizzle predicted, but with absolutely no wind. Perfect for a test flight if it turns out to be flyable. The weather in the morning was very damp and drizzly as predicted, but I decided to give it a go anyway. It looked like it was brightening up, so I got in the car, went a little way down the road and then gave it up. There was a lot of rain on the windscreen and it was looking progressively more overcast, so I didn’t get my test flight in this week after all. At this point I should put a note on the aircraft so I don’t forget that it must be out of trim. Bearing in mind how much I’ve flown the RS352, I’m very likely to forget and launch it next week, only to remember when it’s in the air. I doubt it’s all that far out of trim though, as the carbon push rods allow me to get the new servos in position to millimetre accuracy.

Getting back to this week, I’ve been building my own micro quadcopter.

Quadcopter frames aren’t as complicated to make as fixed wing aircraft, but they’ve traditionally followed the route taken by helicopters of buying plastic and carbon bits that you screw together. There are a lot of 3D printed ones, but I’m fed up with 3D printing as it’s not accurate and the prints keep failing. Also, the printers cost thousands of pounds, so it’s an expensive solution. Making your own frame from scratch is very easy to do and is a lot of fun, so I don’t understand why more people aren’t doing it? I built the DaVinci Aerial Screw in the Summer and have been doing some tests to come up with a plan for a frame that anybody can make. Also, the frame I’ve just made weighs 5 grammes. That’s half the weight of a similar 3D printed one.

This version uses a piece of A4 vinyl sheet which I bought in Paperchase. I made a paper template and cut out a top and bottom in vinyl using scissors. In between there is a sandwich of Depron which is from an old pizza box base. The four plastic tubes for the motors were just an old bit of tube that I found lying around and drilled out to accept the motors. You could probably use an old felt tip pen barrel, but I’ve also got some other ideas about how to attach the motors which might be easier to construct. One other point worth mentioning is that the cyano I’m using causes my black pen marks to run horribly. In the photos above, the clear blue picture is the bottom, while the one with the smudged black pen marks is the top. I’m going to swap the top and bottom around as I really like the blue and white colour.

As you can see from the set squares, I’ve had to build it very accurately in order to make sure that the motors are all at 90 degrees to the frame. I taped the top and bottom vinyl together in order to drill the holes through both so that they line up perfectly. Then the bottom was cyanoed to the Depron. I’m using a cyano with a fixer spray so that I have a bit of “grab”, but I am still able to position things without it sticking immediately. This gives me a bit of “fiddle” time. Once the bottom was stuck, I used a reamer to open up the holes in the Depron, put the motor cylinders in place and used them to locate the top vinyl sheet accurately. I only glued the centre of the top vinyl up to about 20mm from the motor holes in order to locate it. I removed the motor cylinders before it stuck as I need to ensure that these were square.

The final part was to file out tiny amounts from the motor holes to ensure that the motor cylinders went in square, then weighed everything down while I added the final cyano to stick the last bits together.

I’m relying on the fact that I squared off the tops and bottoms of the plastic motor tubes, so, by weighing it down on a flat surface, I guarantee that all four motors are square to one another, even if the frame might be slightly out. There are spacers under the frame which show me how accurately it lines up. Everything looks good from this angle.

Hopefully, the glue will be set soon and I can try it out in the air. Once I’m happy with how it works, then I’ll do a proper plan and building post.

Just to finish, I’ve also been balancing the ATOM autogyro blades, so I’m going to cover these soon. It’s almost at the flying stage now.

New Year’s Day 2017

I wasn’t planning on flying this Sunday, but it seems like it’s a case of New Year, old weather anyway. It was grey, overcast and raining to start with, but now the Sun’s come out and it’s brightened up a bit.

The RS352 has had its yearly overhaul over Christmas and now has four new EMax ES08MA servos replacing the Hitec HS65MG ones which have been giving me problems. It’s a shame really, as the Hitec units are much better servos, they just don’t seem to be compatible with the Futaba R617FS receiver that I use. When you switch it on, they sometimes jitter like crazy until they appear to have found their end point limits. It was like they just had to initialise with full left, full right, full up, full down then they were fine. Except that it looked as though the problem was manifesting itself in the air where it wasn’t before, as I’ve had what felt like the aileron lock until I move the stick left and right to clear it. So, I’ve gone back to the cheap servos that I was using originally and I’ll do a full test of the Hitec servos when I get time to try and understand what was happening.

The wiring and some of the hot melt glue needs tidying up, but it all works.

My other project for 2017 is to finish the ATOM Autogyro and fly it.

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At the moment I’m balancing the blades, then they need covering before I can do the final set up of all the control surfaces. After that it should be flyable, but my time keeps getting taken by the micro quadcopters that we’re building for work. And then there’s the joystick for the quadcopter simulator. I might have a go at that project this afternoon. So many things to do and so little time…