Month: April 2015

Where’s the Rain?

The forecast for this morning was for rain and my lift is on holiday in Australia, so I’m going to have to content myself with flying the quadcopter around inside. I could have taken the flying wing on the bike, but the weather wasn’t looking good. Despite it being obviously very wet when I got up, I haven’t actually seen any real rain, so I think we’ve been lucky here. You wouldn’t bet against it if you saw the big black clouds being blown across the sky though.

Anyway, I’ve been building the mast and rotor head for the ATOM autogyro and this week I’m going to have a go at making the blades. It will be interesting to see how I get on with that as it’s mostly built apart from the motor mount, rotor head, blades and control linkages. I also need to make the canopy, which will probably be from a block of foam, unless I fancy having a go at forming plastic again. The last time I did that was the Vampire canopy, which did work quite well.

RS352 Flies Again

Today was the first flight after losing the prop on the RS352’s last flight. Everything works fine after the repairs, but I was taking it easy, so no prop hanging. I managed four flights, in conditions that were cold, overcast and very windy. One thing I did notice in the 10-15 MPH gusty conditions was that the loops and cuban eights seem to elongate compared to flat calm. I’m not sure why that should be, but it’s something I’ve noticed on a number of occasions, almost as if I’m losing less height in the inverted part of the loop.

Anyway, I was amazed that, despite the really horrible weather, it was incredibly busy this morning. When I turned up there were already two guys with identical blue Corsairs and the two guys from the week before with the DJI Inspire (never got it out of the box), two racing quads (continually getting lost and had a walk to recover them from the outskirts of the field) and a Hobby King Twin Star clone modified for FPV. This aircraft was the one that crashed last time, and was also a bit of a handful this time out in the wind. It looked to be too heavy, but he managed to land it without any damage. As for the two Corsairs, they apparently listened to the weather forecast and got there at 08:30am when it was sunny and calm, so they had done all their flying by the time I arrived with the wind. They left shortly after I arrived.

There were three more arrivals later. One guy had a Delta Ray, a larger foam Cessna and another small foam aircraft. He said his thinking was to bring lots of planes so he could guarantee to get some flying in. I only saw him fly the Cessna though, which actually flew very well in the conditions. Then there was the Multiplex Cularis (which didn’t fly) and the Multiplex Zeno wing which also flew amazingly well. The third guy had a foam Super Cub and Firebird Stratos, both of which flew. Finally, the last arrivals had a big hexcopter, which we got to see fly, but only to hover and translate back and forth a bit.

All in all, it was a really busy morning despite the conditions, with three aircraft in the air for large periods of time.

Too Windy to Fly, Broken Props and Autogyros

It’s much too windy to fly today as we’re just south of all the bad weather. I’m sure this is because of the weather data viewer I’ve been writing for Google Maps, but this is what it looks like this morning:

Meo Office Datapoint synoptic data showing win d speeds for 12 April 2015 at 10Z (11am local time, BST)

Met Office Datapoint synoptic data showing wind speeds for 12 April 2015 at 10Z (11am local time, BST)

The map shows the winds in London as about 20 knots and this is only 11am local time. By 12pm, as I write this, it seems to be getting worse.

Anyway, that means I’ve had some time to do some building. I fixed the broken prop on my RS352 yesterday so the glue had a good 24 hours to set before flying. It’s just that the flying bit hasn’t happened yet because of the weather.

The front of the RS352 all fixed. Note the 45 degree scar in the black foam on the right hand side of the picture

The front of the RS352 all fixed. Note the 45 degree scar in the black foam on the right hand side of the picture

Now I’ve had a chance to investigate the damage a bit more, I’ve revised my previous conclusions as to what took a bite out of the prop. Initially I thought it was the carbon undercarriage, but I now think it was the fibreglass motor mount that did the damage. When I was glueing the black foam with epoxy, I was surprised just how deep the propeller cut had penetrated. It probably went about 15mm back into the foam, with the corner of the aircraft’s lower, or left side fibreglass motor mount taking the bite out of the prop as it went past. There was also quite a bit of cut damage to the lower fuselage behind the motor mount. This was all fixed using 24 hour epoxy and some thin scrap wood which enabled me to get right into the propeller cut and get the glue into where it was most needed.

The ATOM parts with the new C30 rotor head and fibreglass parts

The ATOM parts with the new C30 rotor head and fibreglass parts

The ATOM build has resumed now that I’ve given in and ordered myself a C30 rotor head. I got these from CoolWind, as suggested in the RCM&E plan. The service was excellent as I placed the order on Thursday evening and was saying hello to the postman with the box on Saturday morning. It’s also quite cheap as, for about £20, I got the rotor head, triangular plate and fibreglass parts for the ATOM.

One really important thing to note is that the rotor head is actually delivered assembled upside down. I wouldn’t have known except for reading the build thread on modelflying.co.uk:

http://www.modelflying.co.uk/forums/postings.asp?th=98774&p=3

Also, looking at other people building the autogyro, I seem to be going extremely slowly, so I need to speed up a bit. To this end, I’m going to order some pre-made blade blanks today, plus the motor and all the other equipment I need, so then I will have everything I need to complete it.

Always Check Your Propeller

Always check your propeller is securely tightened. Flight four of the RS352 today became rather interesting when there was a loud pop and I saw something come away from what looked like the front of the aircraft. My first instinct was the propeller as I was part way through a smooth power increase from almost zero throttle. So, back to zero throttle, the aircraft is controllable so I execute a perfect dead-stick landing right in front of me, much to the surprise of the watching quadcopter crowd. I’ve had a scale spinner fail on me in a similar way a few years ago, so I guess I was fairly well prepared.

The detached propeller and hub on the RS352's left wing, showing a "bite" taken out of the propeller.

The detached propeller and hub on the RS352’s left wing, showing a “bite” taken out of the propeller.

While I was busy landing, a very kind passer-by managed to retrieve the propeller, otherwise I would probably have spent a while looking for it in the grass. The picture clearly shows that it’s come loose from the hub. Funnily enough, I had checked all the control surfaces, wing, tail, fin, linkages and general condition of the aircraft while I was waiting for the LiPos to charge, which is my normal routine. I didn’t detect anything wrong with the prop though, but it makes me wonder whether successive prop-hanging practice might be a contributing factor? I had been getting a lot better at this manoeuvre in the previous few flights, although the lack of gale force winds probably helps. The “bite” taken out of the propeller is curious, as I can’t find any damage on the aircraft, other than a small slice out of the black foam on the left side of the motor. It’s almost superficial, the prop cut isn’t deep, but as it’s close to the motor attachment it warrants some epoxy to seal the foam back together. The only thing I can think is that the prop came off, hit the foam fuselage front spinning fast, then the aircraft went over it, with the prop colliding with the carbon undercarriage as it went past. The “bite” mark looks to be on the wrong side of the prop for the direction it was spinning, though, and there is no apparent damage to the carbon undercarriage or any other part of the aircraft.

It’s Easter Sunday today and I was starting to wonder whether I was going to be on my own (and get wet, there were spots of rain), but it turned into a very busy morning. Three guys with quadcopters, an FPV plane and their three young daughters arrived soon after me. Between them they had two racing quads, a DJI Inspire, a Walkera (?) quad similar in size to the HubSan X4 and an FPV equipped Easy Star. After some talk about the “Airheads” pilot and an FPV league that’s being set up, we got down to some flying. The racing quad’s maiden flight and then maiden with FPV was really good, but the FPV plane was obviously nose heavy and uncontrollable, crashing part way around the first circuit after launch. It looked like the nose and FPV kit was damaged, but the rest of the plane seemed OK.

As for the DJI Inspire, it’s not the quadcopters that I have an issue with as much as the idiots who fly them. I’m sure this was the same guy who nearly took my head off last time and he almost did it again. The landing with the spinning blades 2 centimetres from his legs is just stupid and, if he’s hovering above my head close enough for my aircraft to be moving about in the prop wash, then he’s flying much too close to people. Also, the story he told about when the thing started up unexpectedly, jumped into the air and he grabbed it, just left me speechless. The other guy seemed a lot more safety conscious though, so maybe the Darwin principle will hold for quadcopter pilots. All the stupid ones will kill themselves and hopefully not anybody else.

Anyway, I managed three good flights with the RS352 and a fourth aborted flight, which left the quadcopter guys somewhat in awe of how fast and graceful it is in the air, plus they were genuinely shocked that I could fly it back and land perfectly with no prop. I also four flights with the HubSan X4, which was going really well with its new motor. Near the end of the morning, we had the guy with the Stryker show up again and get in a single flight with his extremely quick aircraft.

Finally, I’ve had some time off so I’ve been building some of the ATOM. I’ve been working on getting the servos in, but, because I’m using Futaba S3106’s from my old Simprop Cap231EX, it’s a bit harder to fit them in. This means that the Cap231 probably isn’t going to fly again, as the last flight some years ago showed up extreme structural failure in the fuselage, which had been getting gradually worse for a while. I had been patching it up, but foam just fails at the point where the patch ends, so it ends up like trying to plug a leak in a sponge. In the end it’s for the best. Also, I’ve already used the motor and ESC in my mini flying wing, so the other two servos are coming out next. Here is the ATOM so far:

The ATOM autogyro with an aileron or elevator servo installed.

The ATOM autogyro with an aileron or elevator servo installed.

You can see one of the aileron or elevator servos installed, while I’m still working on getting the rudder servo into position at the rear of the fuselage. The boom, tail and mast are not glued in yet, so the whole thing still comes apart easily. It’s very close to needing the head and rotor blades, but I still need to order myself a motor. Last time I ordered something from RobotBirds, I bought a GT Power Watt Meter, which is proving very useful for gauging LiPo capacity:

GT Power Watt Meter

GT Power Watt Meter

It’s a nifty little gadget, but I haven’t quite figured out how to use all the functions yet.

That’s it, I’m off to do some more work on the flight simulator and build some more autogyro.