Month: May 2017

Variety in Flight

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

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

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

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

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

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

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Propeller Cubed

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Look, no propeller!

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

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

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

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

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

 

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

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

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

There’s Nothing Happening This Week

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

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

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

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

Where is Everybody?

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

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

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