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.

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