Heli-Max has posted a nice promo-vid for their rebranded Walkera 4G6. Some great flying, inverted funnels and the like. I also like that they have the plastic rotor head in their setup. Nice canopy design, too.
Micro Linear Servo 1.5g
Finally there is an alternative to the Spektrum linear servos. Here comes HK with a 1.5g micro servo for only $5.99, which will be available as a right- and a left-servo version. It was announced only 2 weeks ago on RCGroups.com by manufacturer Assan. Right now there is only a 2-servo V-Tail version ($22) available at HK but the single servos are expected soon.
Unlike with the Spektrum model, the electronics of these new servos are on a seperate PCB. So it might be possible to make the servo even lighter by removing parts of the PCB on which the actual servomotor and pot are mounted. Depending on the ohm-rating of the pot it might also be possible to use a different (maybe lighter) controlling board.
New HK micro linear servo
Specs:
Type: Digital
Application: Ultra-Micro Aircraft
Torque: 29.5g of Force
Speed: 0.11 sec @3.7V
Voltage: 3.7V~4.2V
Stroke: 7.4mm
Dimensions: 20.8 x 12 x 7mm
Connector type: JR
If you’re into scale-ish looking submicro helis this is for you: Nanoheli (nanoheli.net) is developing a flexible shaftdrive solution for the tailrotor of the Walkera 4G6 / 4#6. The flexible shaftdrive is designed for the scale-ish bodies that nanoheli is offering. Also just announced is the Sikorsky S-61 Sea King body from Nanoheli.
First pics of the flexdrive shaft look promising, but we don’t know yet how the servo linkage is going to work. Lets see what Nanoheli will come up with.
Flexible shaftdrive for the Walkera 4G6/4#6 from Nanoheli
As posted before, the Walkera RX2609 can be modded to a 2.2gm gyro-less RX for micro planes etc. Now here is the mod to use all 6 channels. The 6th channel is gyro-sense which normally goes directly into the gyro. Ive routed the gyro-sense to the SX servo socket. The SX socket was originally used to output the tail servo signal generated by the gyro. Now it put out the gyro-sense / AUX2 signal directly. Only to pad on the PCB have to be connected for this.
Walkera RX 2609 6 Channel mod
Here is my Walkera 4G6 landing gear. Hybrid design made from parts of the original 4G6 gear and an old HM52#1 gear (see my older post here), held together by shrink tube and ca. The 4G6 gear is super lightweight and unbrakable and the HM52#1 mounting provides a wider spread so the heli has more stability on the ground and during landings. Total weight incl. screws is 2.2gm only, so its weight is even less then the original Walkera 4G6 LG (2.4gm).
Hybrid 4G6 / HM52 landing gear on the 4G6 - sideview
Hybrid 4G6 / HM52 landing gear on the 4G6 - mounting
Hybrid 4G6 / HM52 landing gear on the 4G6
only 2.22gm 4G6 / HM52 landing gear
Now its official. The Walkera 4G6 2609 RX can be separated. One of the boards is the gyro, the other one is RX only (that is the board with all the servo connectors). After seperating the RX board is only 2.25gm (see pic below). As is the thing has 5 channels but it might be possible to use the gyro sens. channel as well, making it fully 6 ch.
The RX will be used in my BLiX-Twin.
Here is a short video with the seperated RX alive:
gyroless RX2609 2.25gm
As the 30mm wide Zippy lipos (450, 600mAh) wont fits into the stock Walkera 4G6 landing gear i have removed the battery holder from and cut the LG in the middle of the front mounting. Drilled a second whole and used a longer screw to mount it.
Now the distance between the struts big enough for 30mm Zippys. Lipo is held by a rubber band. Maybe not the most elegant solution, but less weight than any other landing gear. Stabilty of the LG is still strong.
Walkera 4G6 landing gear modified for Zippy lipos
There have been questions about how to set up the Gaui mixerarms on the Walkera 4G6 heli correctly.
When using the metal bladegrips you will need spacers in order to have the ball links exactly in the center over the flybar.
I took some M1 hexnuts, drilled them to 1.5mm inner diameter and used them as spacers. they are about 0.7mm thick, this is perfect for my setup. What kind of spacer thickness to use depends on how tight your bladegrips are on the feathering shaft, the space between rotorhead and bladegrips. 0.7mm spacers should be perfect for the stock setup. If you use the plastic bladegrips the bosses have to be trimmed down a bit.
The video shows how to check if you have the correct spacers. Notice that the ball links line up almost perfectly in the video. If they are not in line you will get friction and vibrations in the rotorhead.
Image below shows all the detail to look for.
Gaui Mixerarms on the Walkera 4G6 - correct setup
The stock Walkera 4G6 mixer arms have way too much play, also no ball bearing. So i took some aluminum mixer arms from the Gaui EP100 V2 aka Minizoom Pro V2, part 203580 (silver) or part 203640 (black). The original ball links can be removed and the Walkera ball links fit into the threads in the Gaui parts. The Gaui parts work with the plastic Walkera bladegrips, if you use the metal bladegrips some spacers are necessary. The Gaui arms are a bit shorter but that doesnt seem to change the feel.
Result: The heli feels much more precise and most unexpected pitch-jumps are gone. Still have to shorten the plasic on the bladeholders where the screw goes in.
Thanks to Don on RCGroups – i first saw the mod from him.
Here is a video from RCGroups user jaguar_5, showing the difference:
Walkera 4G6 with Gaui EP100 mixer arms
Gaui EP100 mixer arms
Walkera 4G6 mixer arms (left) vs. Gaui EP100 mixer arms (right)
finally it’s flying…
Walkera 2609 RX (from 4G6 Heli), Walkera 2801Pro TX, using PROGMIX for differential thrust, AP02 Outrunner Motors, XP 3A ESCs, proportional actuator mod elevator, 240mAh or 400mAh 20C Zippy, AUW 30gm (240mAh), AUW 34gm (400mAh)
Some impressions:
After all, it’s still an X-Twin Acrobat/Rolling Fury, it feels pretty similar to the stock version. Stability from the dihedral is still there but a bit lower (due to higher weight i guess).
What’s really great is that there is no more slow reaction or range issues. Also the roll-rate is much higher, i can really turn/roll it from side to side in no time. Still playing around with the mixcurve though. At first it was way to nervous around midstick aileron i.e. rolling like crazy. I’ve flattened the curve near midstick and thats much better.
Also it is much faster due to higher weight an the brushless motors.
I’ve put some tape on the props to get more thrust and this worked, static thrust of the plane is now near 30g with fresh lipo. I was getting about 20g static with one motor alone on my testbed – don’t know what happend. Even with a 1s 850mah Zippy only 30g for the plane.
Today was mostly calm but with some nasty gusts so not the perfect conditions, im really looking forward to fly it under perfect condition. Indoor is not an option because its way to fast (3-court gym wouldnt even be big enough i guess).
Little problem with the bl setup is that the motors / esc sometimes cut off on startup, i.e. i have to avoid pulling throttle down too far because the ESCs take about a second to initialize and start up the motors again – this second will often result in a crash.
It seems that i have gotten one bad motor that does this cutoff on startup more often, maybe ill replace that one. Or its the 3A ESCs that are to weak.
The elevator actuator seems to be at it’s limit with this setup. Not enough torque. I’ve tried to make the elevator area bigger with some tape but then the actuator cannot pull the elevator all the way due to the airflow from the props. So maybe i’ll go for a 1.5g Spektrum servo.
Whats really great is that the thing still has mad power with 34g AUW (400mAh Zippy).
To sum it up, the RX/TX with mixing option, super fast reaction and no range issues is the best part, the BL motors performance and cutoffs are not quite perfect yet. Overall its still an acrobat / fury and i like the mod for that.
23.6gm: weight excl. Lipo. BL X-Twin.
the guts
6.1gm: 240mAh Zippy
10.1gm: 400mAh Zippy
