Long-term Memory

Place: Halle
Tanks flown: 4
Time flown: 1h00 (cumulative model timer: 28h56)
Rx battery recharged with: 1373 mAh (but more than 2 hours after the last flight)
Tx battery recharged with: 459 mAh
Glow heater battery recharged with: 193 mAh
Starter battery recharged with: 30 mAh

Comment:
Another beautiful day at the field, although the wind was gusty.

Practiced autorotations a lot. I’m mostly following this guide: try to land with less and less power available. I started out at 30%. The last attempt was at 15% power.

I’m a bit surprised how rough you can land the Raptor 50. Just make sure that you don’t have sideways or backward motion, as it might tip over or bend the tail boom.

Continue reading ‘Flight log 2008-09-28’ »

Place: Halle
Tanks flown: 3
Time flown: 0h46 (cumulative model timer: 27h56)
Rx battery recharged with: 221+800 mAh
Tx battery recharged with: 470 mAh
Glow heater battery recharged with: 430 mAh
Starter battery recharged with: 115 mAh

Comment:
Very nice weather: around 20°C and blue skies. Hardly any wind at first, but it got stronger during the afternoon.

First flight was mostly tuning the new rotorblades to get them to track correctly. I adjusted a total of 3 turns to get it to an acceptable level. The black blade still is a bit low, but probably only 0.5 turn or so.

The Rx battery had the same problem as before. I’m guessing it is still warm from the flight. I’ll try to recharge it later.

Other flight where mainly to get some footage from my FlyCamOne2. There is still a big “wobble” all over the screen caused by the vibration, but it’s a lot better than the previous attempt.

Continue reading ‘Flight log 2008-09-27’ »

Place: Halle
Tanks flown: 0.3
Time flown: 0h07 (cumulative model timer: 27h10)
Rx battery recharged with: 1665 mAh
Tx battery recharged with: 583 mAh
Glow heater battery recharged with: 561 mAh
Starter battery recharged with: 148 mAh

Comment:
Same weather as yesterday. I mounted my FlyCamOne2 and wanted to give that a try. Somehow, it managed to record 122 pieces of video instead of the 2 shots I planned. I glued the pieces together, but the result is “jumpy”, the quality is bad, it shakes like hell and is overcompressed, but just in case you still want to watch it: 2m18s, 13.7MB (x264 video, ogg-vorbis audio, matroska container, VLC plays this just fine).

After 2 minutes of flight, I suddenly hear a loud “tack”, but didn’t see or feel anything strange. I landed the heli promptly anyway to do a full check. The sound was fairly loud, since the heli was at least 100m away and was clearly audible. I checked the main and tail-drive gears, but none of them showed any damage. The rotor looked OK as well, until I examined it a bit closer:

The plastic foil at the top-tip of the blade somehow got loose and teared. This tip was traveling at around 430km/h (67cm from the axis, rotating at 1700rpm), which makes a lot of noise when something hits this wind.

Just swapping the blades with the spare (wooden) blades had my bird ready to fly again.

Place: Halle
Tanks flown: 3
Time flown: 0h51 (cumulative model timer: 27h03)
Rx battery recharged with: not recharged
Tx battery recharged with: not recharged
Glow heater battery recharged with: not recharged
Starter battery recharged with: not recharge

Comment:
A cold but sunny day with some wind.

I just flew around, trying to make normal turns (instead of stall turns). I also worked on my autorotation skills: did some (8 or so) auto’s from 1m height; did some side-in and nose-in landings; tried an “airplane-approach” to learn to keep forward speed during descend.

And I emptied my 5th bottle (3.8l each) of fuel!

When learning to fly my remote controlled helicopter I was also interested in the technical side. In this post I’ll write down what I discovered about the “air interface”.

In most (every?) countries, the use of the electromagnetic spectrum is limited by law. Some frequencies are almost universally reserved for public use (the 2.4GHz band used by e.g. WLANs). Other bands are highly restricted (the band around 120MHz, used for communication with real airplanes). In Belgium, the 35MHz band is reserved exclusively for model aircrafts. Other bands popular around the world are the 40MHz and 72MHz band.

Continue reading ‘Remote controlled aircrafts: the air interface’ »

Place: Halle
Tanks flown: 2
Time flown: 0h28+0h18 (cumulative model timer: 26h12)
Rx battery recharged with: -2440 (discharged at 0.66A) + 3523 mAh
Tx battery recharged with: 471 mAh
Glow heater battery recharged with: 552 mAh
Starter battery recharged with: 145 mAh

Comment:
Finally we got a nice summer-day, although it was fairly windy.

After my adventure from yesterday, I decided that I should practice auto-rotations: I’ll need them anyway.

Started off by doing a nose-in, left and right landing. Also tried a high-altitude throttle-hold to get a feeling of the switch. There is still a long way to go, but it’s a start.

Giving my Rx battery a full cycle, hopefully this helps to get it charged.

The 0h18 Tx time is for the spectral analysis.

Place: Halle
Tanks flown: 3
Time flown: 0h49 (cumulative model timer: 25h26)
Rx battery recharged with: 151+204+153+403+ mAh
Tx battery recharged with: 749 mAh
Glow heater battery recharged with:
Starter battery recharged with:

Comment:
A nice after-work flying session with very little wind.

Practiced some more figure-8’s which start looking like real 8’s now. Did my first nose-in landing; it was just as bad as my first tail-in landing…

The last flight ended by a forced auto-rotation: the fuel-line got disconnected from the engine lock with the obvious result. Luckily, this happened at the end of the flight when I was hovering at .5m. I noticed that the fuel-line was vibrating heavily. By the time I realized that I should check it out, the engine quited…

Also, there seems to be a problem charging the Rx battery…

As mentioned before, the cooling fan of my engine needed some attention:

Continue reading ‘Flight log 2008-08-24 – Follow up’ »

Place: Halle
Tanks flown: 0.5
Time flown: 0h17 (cumulative model timer: 24h37)
Rx battery recharged with:
Tx battery recharged with:
Glow heater battery recharged with:
Starter battery recharged with:

Comment:
Windy day at the field with dark rainclouds at the horizon. I took my chances anyway and practiced flying in windy conditions.

While preparing for the second flight, somehow the cooling-fan came loose (again)…

Place: Halle
Tanks flown: 2
Time flown: 1h01 (cumulative model timer: 24h20) (including a lot of setup-time for the governor)
Rx battery recharged with: 268+1472 mAh (same behavior as some weeks ago)
Tx battery recharged with: 554 mAh
Glow heater battery recharged with: 439 mAh
Starter battery recharged with: 141 mAh

Comment:
I just bought myself a governor and needed to test it out. Besides that, a fairly calm day at the field. Besides testing out the governor, I continued to exercise my figure-8’s and nose-in hoover. After the last flight, I noticed that the rotor wasn’t rotating as freely as it used to.

When investigating this at home, the tail rotor made a slight rubbing sound:

The locking pin to keep the tail rotor shaft in place came out of its place. Pushing it back and re-tightening the set screw solved this problem.

Also, I basically undid the tracking adjustment: “black” was too high, so I decreased its pitch by 1 turn.

The governor

A governor is a device that stabilizes the rotor speed using a feedback mechanism. The Futaba GV-1 uses a Hall sensor to detect the magnets attached to the engine-fan. Here is the report about the device itself, its installation and the first test results.

From the 2 flights I did with the governor, I’m fairly happy with it. It does what I want it to do: govern the throttle to keep constant RPM. I must admit that I don’t (yet) do very demanding maneuvers…

Continue reading ‘Flight log 2008-08-15 – Governor’ »