Long-term Memory

Place: Halle
Tanks flown: 2
Time flown: 1h00 (cumulative model timer: 30h52)
Rx battery recharged with: 272+392+overnight trickle mAh (again)
Tx battery recharged with: 489+overnight trickle mAh
Glow heater battery recharged with: 1473 mAh
Starter battery recharged with: 498 mAh

Comment:
Before this flight, I adjusted the pitch and throttle curves and activated the IdleUp2 position. This is the updated table from before:

Today was the first day with reasonable weather. It was still windy, but almost no gusts.

Had some trouble starting the engine. Turns out there was some dirt in the needle of the carburator. Simply turning the needle a bit (5 ticks) open, starting the engine and returning the needle to its original position solved this issue (although it took me more than 30 minutes to figure it out).

No spectacular flight for this first time, just some hoovering in different directions. The second flight was a bit more entertaining: I rehearsed my stall-turns and tried some standard patterns, which was quite a challenge in these (cross)wind conditions.

Place: Sporthall Braillard, Ruisbroek
Flights: 2
Time flown: 0h19 (cumulative model timer: 2h56)
Heli battery recharged with: (1) 1639 mAh; (2) balanced 1896 mAh;
Tx battery recharged with: not recharged

Comments:
Indoor flying. The tail vibrations mentioned earlier are probably caused by some slop in the linkage. I tried various gyro-gain settings and the vibrations did not seem to be affected.

Place: Sporthall Braillard, Ruisbroek
Flights: 3
Time flown: 0h27 (cumulative model timer: 2h37)
Heli battery recharged with: (1) 1566 mAh; (2) 1844 mAh; (1) 1774 mAh
Tx battery recharged with: 607 mAh
Starter battery recharged with: 1187 mAh

Comments:
Indoor flying. Finally got the chance to properly trim my miniTitan. The gyro still needs some tuning: when I stop the rudder command, the tail overshoots, then comes back. Also sometimes I notice the tail vibrating left-right at around 3Hz. Unsure if this is a gyro problem or just a vibration problem.

I tried recharging my LiPo with the starter battery, but after 15′ (680mAh) of delivering 2.5A the charger reported that the source battery was too low… Luckily one of my friends had some spare 12V power.

On the third flight I tried getting some forward speed. Even though it was a big indoor hall, this machine wants more…

Place: Home garden
Flights: 1
Time flown: 0h25 (cumulative model timer: 2h10)
Heli battery recharged with: 1714 mAh
Tx battery recharged with: not recharged

Comments:
Demonstration for the family. Flew for 7 minutes or 68%, guestimating on the charged-in capacity.

Right after the flight, the battery was warm (I’d guess somewhere 35-40°C), the engine was fairly warm (around 50°C) and the ESC was hot (60-70°C). The temperatures are measured with my fingertips, so they are very accurate…

Place: Home garden
Flights: 1
Time flown: 0h08 (cumulative model timer: 1h45)
Heli battery recharged with: 1185 mAh
Tx battery recharged with: 1021 mAh

Comments:
First real flight. One of the things I need to calibrate is the flight duration of my battery. I flew 5m55s on this battery and it was recharged with 1158 mAh. Extrapolating this gives an max flight time of around 12 minutes and 28 seconds.

I got myself a new RC helicopter. It’s an electric one so I can fly indoors.

Here is the partlist and some basic specs:

• Thunder Tiger miniTitan E325
  624mm long, 120mm wide, 210mm heigh, 728mm main rotor diameter, 156mm tail rotor diameter, 750g weight
• Thunder Tiger Ripper OBL Series Helicopter Brushless Motor 29/35-10H (mine came with the miniTitan kit)
  3500rpm/V, 20A continuous, 30A.60s burst, 12 stator windings, 8 permanent magnets on the (outrunner) rotor
• ACE R/C Brushless Motors Speed Control ESC BLC-40 (included in the kit as well)
  40A continuous, optional governor function
• 3x Hitec HS 65 MG (more detailed specs)
  4.8 – 6V input voltage, 60° in 0.14s (4.8V, no load), 1.8kg.cm stall torque
• Futaba S-9257 (more detailed specs)
  digital, 4.8V input voltage, 60° in 0.08s (no load), 2.0kg.cm stall torque
• R319DPS receiver – 35MHz band
  1024PCM receiver, 8 proportional channels, 1 digital channel
• Futabe GY401 Gyro
  Solid state gyroscope with Heading Hold (AVCS)
• FLIGHTPOWER 3s1p 25C 2500mA 11,1V
  Continuous discharge 25C/62.5A, Climbouts 35C/87.5A, Max burst 50C/125.0A
• Flightpower V-balancer
  LiPo balancer for up to 6s packs

Continue reading ‘The new toy: mini Titan E325’ »

Place: Halle
Tanks flown: 3
Time flown: 0h56 (cumulative model timer: 29h52)
Rx battery recharged with: 728 mAh
Tx battery recharged with: not recharged
Glow heater battery recharged with: 462 mAh
Starter battery recharged with: 133 mAh

Comment:
Another beautiful autumn day (which are fairly rare in Belgium), although the sun was hanging low. Naturally, I was able to pilot my heli straight into the sun. Apart from the black spot in my vision the next 3 minutes, nothing got damaged in the process.

Tried and succeeded in a full auto-rotation with 0% engine power (previous attempts where with some power). Turns out that it isn’t too much different from 15%. Even at 15%, the engine is hardly engaging the clutch so it barely provides power.

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.