It's been two weeks since i last flew, meanwhile i installed some nice carbon blades and tail, did some nice setup as well... So we've got a sunny Saturday, i took my girlfriend for a walk and decided to fly some rounds over a nearby soccer field... The rest is history... enjoy...
Here we go, this is a video of my HBK2:
http://www.youtube.com/watch?v=PGsoSs3JDOQ
http://www.youtube.com/watch?v=Jce9q1Fq0fA
It has the following add-ons:
- Esky 3800KV brushless motor and 25A ESC.
- Saehan 2100mAh 16C 3s1p LiPo Battery.
- Esky heading lock gyro.
- Aluminum rotor head and tail gear box.
- Carbon fiber paddles and tail blades.
- Tuning tail belt pulley with a greater diameter (Xtreme).
- Tuning titanium adjustable push rods (Xtreme).
- Self-made Battery monitor, separately monitors each of the lipo cells and triggrs 4 ultra bright LEDs on low voltage.
- Self-made LED position lights.
It seems that there is a full carbon version of the HBK2, however the carbon fiber frame is still not selling separately...
Check out my heli on Youtube:
http://www.youtube.com/watch?v=_bnbA1VWEZQ&mode=user&search=
By the way, the E_Sky king is there, but more on that one later...
Last week i have ordered an E_Sky Honey Bee King 2, RTF together with a brushless motor kit, heading lock gyro, 2 additional 1500 mAh lipos and some small stuff!
I bought it from Hong Kong at www.rc711.com, apparently the official dealer of E_Sky. The whole thing cost me only 244€, given that the RTF model is only 100€.
The bad news is that the package was apparently delivered to a Customs office, so i am preparing for a long wait... and for paying some 60€ of taxes :-(. lets see...
I have found out the the E_Sky micro servos are the main source of radio interference... I have noticed this after replacing one failed servo, the radio glitches have decreased drastically. Note that the servo was working properly before it failed, but apparently causing severe interference.
Then i have connected an oscilloscope to the 5V BEC power supply and was not surprised to see huge (about 1V) ripples whenever one of the servos was operating. I solved this noisy power supply problem by using one ESC's BEC to feed the Receiver, Gyro and Y-Tail mixer, and the other ESC's BEC to feed the servos.
Now the newly (!) replaced servo is about to fail once again (shaking from time to time and apparently causing interference once again); so i have ordered a pair of other brand servos from HK. Let's see if they are better (link).
The new ESCs have arrived more than one week ago, but i've only now had time to blog about them.
So, i should say the the units are a bit bigger than the TowerPro MAG8, they also use the ATMEL Atmega 8 microcontroller, only that this one is in a bigger package.
The programming card is very handy, and it enabled me to change many settings, the most important are soft start, timing advance and PWM frequency; these settings were not available on the TowerPro.
I have made some thrust vs. current measurements, it was clear that the new controllers are way more efficient than the TowerPros, even when the timing andvance and PWM were not optimally set.
Speaking about settings, i found that middle timing and 16 kHz PWM frequency gave the best results with CD-ROM motors.
The main reason i bought new ESCs was the dynamic throttle limits of the TowerPro. These new ESCs also seem to have some kind of a dynamic throttle limit, but its effects are only noticeable when the throttle and rudder are set to maximum.
Another unpleasant behavior of the TowerPros is the tail shaking when the battery gets low, this was not noticed with the new ESCs.
Apart from installing new ESCs, one motor was completely replaced and the other one has got a new stator. Both motors were wound 13 turns in 0.45mm wire in a star configuration.
Flight times remained roughly the same though the handling got noticeably better. One way to make a significant improvement is to install an E_Sky heading lock gyro, i dont know if i would do that since i have already ordered a brand new E_Sky Honey Bee King 2!
