Month: August 2014

Last Day Of August

Today is the last day of August, so Autumn starts tomorrow, but at least we got one final day of Summer sun to fly in, even if it was a bit windy. Wind is good, it blows the sunny holes in the cloud past more quickly.

I managed three flights with the RS352, but also did a maiden flight for somebody else. I think his aircraft was a Hitec Sky Scout [link], as it wasn’t a Multiplex Easy Star, but one of the clones (need to check this, as a Scout is reportedly identical to an Easy Star II). After checking the control surface deflections and discovering the elevator to be working the wrong way round, I offered to launch while he flew it. In the event I flew it while he launched, but it flew like a dream. I think I put in one click of right aileron, but that was it. After getting it to a safe height I hooked the neck strap over my head and glasses and handed over the controller. That bit actually worried me more, as I always think I’m going to flip my glasses off and not be able to see the plane. Now, for somebody who had only flown multi-rotors before, his first flight was very impressive, resulting in a perfect landing.

I also launched on the maiden flight of another big glider (TODO: check type, T tail, looks like a Discus, 3.5m? Maybe Slough RC Condor?). With nothing to hold on to underneath except a slippery curved fuselage, this was interesting, but it had the power to get away without any problem. Control problems with the ailerons eventually led to its landing a long way out, with the fuselage getting scraped during the hard landing. It looked like the ailerons were unresponsive, then suddenly flipped the aircraft round and put the nose 90 degrees down.

I also watched a Blade 350QX quadcopter being flown [link], which reminds me that I need to get some new LiPos for my X4 and Q4 so I can fly quads again.

 

Sunny Eight

By some miracle, the wind and rain isn’t due until tomorrow and today is sunny and warm with only light winds. I also managed to get in eight flights this morning, which could be a record. My transmitter was showing 40 minutes use, so that’s 4×10 minute flights of the RS352. Here’s how I did it:

  1. Hobby Zone Champ
  2. Hobby Zone Mini Super Cub? White with blue trim, bigger version of the Champ with a geared motor. Rudder/elevator with throttle. The throttle is very strange as the Tx is spring loaded to return to the centre with zero throttle being in the middle. No anti-crash either. (need to look up what this aircraft actually is).
  3. RS352
  4. Hubsan Q4, micro quadcopter. You know there is no wind when you can fly this outdoors
  5. Hobby Zone Champ (didn’t want to come down, so I ended up spinning it)
  6. RS352
  7. RS352
  8. RS352

The super cub (number 2) was quite strange to fly as it didn’t have enough power. Apparently it’s supposed to use a 3S LiPo while I was flying on a 2S. Every time I used the throttle, the nose would rise, so I was constantly preventing it from stalling. Also, at low speed the small rudder didn’t have the authority to initiate a turn, so it needed some coaxing around the sky. Not exactly easy for a beginner, which is the target market for this aircraft. It’s quite fun to fly though, and could almost do a reasonable loop after some persuading from the audience, as it was their aircraft I was flying.

Stupidly Windy

I got to the park, opened the car door and got hit by the gale force wind. I should have given up on flying earlier as I could see how windy and overcast it was. It looks like it’s just the quadcopter this weekend.

I’ve actually been having problems with the charging jack on my Futaba Field Force 8 recently. Having opened it up, replacing the jack looks very difficult and I can’t find anything obviously wrong with it. I’ve tried cleaning it and very carefully bending the contact up to make a better connection, but nothing seems to work. The weird thing is that by pushing the jack in and then gently pulling it out you can get it to connect. That would suggest a loose connection where it attaches to the motherboard.

Anyway, the weather is now being really annoying. Suddenly it’s warm and sunny with blue skies and light clouds everywhere. The wind is still gale force though, so it only looks like a nice day. This might be the time to rebuild my flight simulator project as I’ve been meaning to do it for ages and just never had the time.

Wing Thing Two Tests

I’ve had some time to take the Wing Thing Two apart to do some testing, which turned out to be very interesting.

Firstly, I ran the HET Typhoon Micro 6/3D motor on the bench with the Graupner 8×4.5 folding prop, just as the final flights in the air had been. Any throttle setting above about 60% resulted in running problems with the motor. It looked as though the voltage and RPM was too high, causing the speed controller to skip. Measuring the power and RPM at this setting I obtained the following data:

135 watts, 13.3 amps, 6000 RPM

That’s with a Tsunami 10A controller with a 3S 1300mAH LiPo, so I’m exceeding the 10A controller limit and 90W stated maximum power output. The Kv for the motor is 1500 and idle RPM 10,800, so the 6,000 RPM measured is 56%, which is much lower than I would like.

Next, I extracted the motor from the fuselage and this is what I discovered:

IMG_20140811_164439

It appears that the first crash pushed the rotating part of the motor backwards (left=front of aircraft in picture), leaving the magnets only partially exposed. This must completely change the motor characteristics, which is why it was behaving rather oddly on the bench test. I’ve never seen a motor do this before, so it was a new one on me. Anyway, the 3S LiPo and 8×4.5 prop should be in the right area for this type of aircraft, so I’m going to fix the motor, reassemble everything and test again.

Just to round things off, I also weighed all the components so I have some data to put into the simulator:

Fuselage, Motor, ESC, Receiver (FrSky DR4-II), Prop: 139g

Hyperion 1300 mAH 3S LiPo: 108g

2xOuter Wing Panels, Centre Wing Section, 2xFins, Wing Joiners, 2x Elevon Servos: 210g

So, the total flying weight was 457g.

 

No Flying This Week

There’s no flying this week due to the fact that the park is closed for the cycle race, but the remnants of hurricane Bertha would have put paid to it anyway. Gale force winds (40mph+) and torrential rain would have made it impossible.

Having said that, I did have a few flights indoors with my Hubsan Q4 quadcopter. I must be doing something wrong with the recharging as I’m only getting flights of a couple of minutes before all the lights start flashing at me to land. It’s quite a fun thing, but I like the X4 much better as it’s far more capable of flying outside and in quite windy conditions with longer duration. Unfortunately, I think the LiPos are wrecked (I’m already on my second set) so I’ll have to order some more.

Not being able to get out has given me time to do some bench testing on the “Wing Thing Two”, which will follow in a later post.

Sun and Lots of Wind

It seems the weather is back to normal with a 15mph wind making it almost unflyable. I took the RS352 out on three flights, but, with significant low level turbulence and even stronger wind higher up, aerobatics are a bit hit or miss. The strange thing is that straight off from the first flight, I could put the RS352 into a fairly stable hover and watch as it drifted downwind. It’s actually harder to hover in flat calm conditions and I still haven’t figured out the reason.

One thing I did manage to get right was a stall turn with a really positive stall and direction change at the stop. I only got it right once and I’m not sure whether it was the wind affecting the aircraft, or the small amount of left aileron coupled with the full left rudder deflection at the top which did it. Either way, that’s exactly how it’s supposed to look.

The hexcopter wasn’t back this week, but I was joined by a small foam wing, larger foam glider (suffering from lack of elevator and terminal dives), plus a spacewalker.