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Old May 11, 2014, 10:17 AM
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Tokyo Setagaya-Ku, Japan
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A 4 blade conversion of Agusta 400 coaxial by a Walkera G400

Hi guys,

I have been tackling a 4-blade conversion of an Art-Tech Agusta 109 (400 size coaxial helicopter) in my blog:
http://www.rcgroups.com/forums/showthread.php?t=2004015

Finally I succeeded in getting a smooth flight by using a Walkera G400 6-axis gyro/receiver. I used a Copter X rigid head+composite blades. Very stable and reliable. Almost the same control feeling with other Walkera 6 axis gyro helicopters.

Agusta 400+Walkera G400 (3 min 19 sec)
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Old May 11, 2014, 11:24 AM
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Not Bad
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Old May 12, 2014, 07:24 PM
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Tokyo Setagaya-Ku, Japan
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Hi Bad Creation,

Here are some pictures. The most important point of usage of Walkera receiver/gyros is the cost performance ; for example, the receiver/gyro for a G400 is sold at $99.99 in Miracle Mart! (GPS and a compass are unnecessary in a 6-axis mode).
http://www.miracle-mart.com/store/in...ducts_id=11155

Spec:
0, Main rotor diam. 617mm, Tail rotot diam: 140mm, AUW; about 1000g,
1, Art-Tech coaxial Agusta 400 fuselage and its plastic chassis,
2, Copter X rigid 4-blade head (after some reformation)+ composite 4 blades,
3, Walkera G400 receiver/6-axis gyro+Walkera special digital & metal gear servos for a G400+Devention 7 transmitter,
4, a main brushless motor Hyperion HP-HS2221 with KV=1630 + 13 tooth 0.5 mod. pinion+ Erazor 450 spur gear (105 teeth, 0.5 mod.),
5, the tail motor: AEO C20 PRO with KV=1550 + a short cut APC 7X5 propeller for a gas power,
6, a main controller, Kontronik Smile 30-6-18 in a governor mode + a RCHobbygear signal converter (yellow one, for a Maste CP tail),
7, a Walkera signal converter+a tail brushless controller 10A,
8, Hyperion 3S25C-2100mAh Lipo.
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Old May 13, 2014, 07:12 PM
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Tokyo Setagaya-Ku, Japan
Joined Jun 2004
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Hi guys,

Here are some pictures of reformation of the plastic chassis. We install the servos WK-7602 (a high frequency digital servo with metal gears) only by some thin both-sided tapes and aluminum supporters; no usage of screws. The case of a WK7602 has only 2 screws ; one side of the case is not fastened by screws, and so at a main rotor crash this side opens up. As a result the servos and the linkages might have no damage ( This was my experience!).

Please be careful that the output signal of a G400 receiver/gyro is not a standard one!

I investigated the receiver outputs by an oscilloscope. Then, I obtained the following data:

1) the outputs for servos: the period of a pulse is 3.2 ms (a usual one is 15 ms) and the width of 3V-height varies 1.1ms~1.9ms corresponding to the stick position. So the servo motors of other makers may not work. (On the other hand, a WK-7602 works under a standard servo pulse!) Further, be careful that the rotation direction of a Walkera servo is opposite to the rotation direction of other maker servos!

2) the outputs for motor controllers (throttle and rudder): the period of a pulse is 0.5 ms in both cases. So very high frequency! Further the width of 3V-height varies 0 ms~0.5ms. So one needs some converters.

3) The receiver needs the power-check information from the main controller for the flight; this information is given by a servo-wire from the main controller. The output of this wire is 1.8~2.0 V constant when 3 cell, and 1.2~1.3 V when 2 cell. Though, this function can be cancelled by installing some small part (a 10 K ohm register between the signal and the plus) to the power-check channel.
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Old May 14, 2014, 12:19 PM
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WOW u put some time and though into that
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Old Jul 01, 2014, 05:01 AM
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Tokyo Setagaya-Ku, Japan
Joined Jun 2004
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Hi guys,

I replaced the rigid 4-blade head by the floating 4-blade head of Copter X. This is because I want to try the taxiing take-off.

In order to avoid over-flap of blades, I installed some heat tubes at the hinges.
The result is not so clear, but I feel that the taxiing becomes easier.

K2-tokyo
PS. I found a french RC-shop who is selling this model (double rotor Agusta 400), probably, the last one?:
http://www.hobbygaga.com/fr-art-tech...11-p257141.htm
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Old Jul 01, 2014, 11:55 AM
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That's Pretty interesting!!!
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Old Jul 01, 2014, 04:58 PM
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Hi Bad Creation,

Thank you for your interests.

I have some video of Swiss rescue Rega's Agusta A109K2's. In that video, I found some scenes of taxiing take-off and taxiing landing. I have never succeeded in such taxiings of my Agusta 109 scale helicopters until now; Hirobo Shuttle Agusta and Graupner's 60-size Agusta. Though, 15~20 years ago, the battery capacity was too small, and so it was wasteful to spend the power before taking-off.

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That's Pretty interesting!!!
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Old Jul 02, 2014, 12:11 PM
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I understand where your coming from definitely want to spend more time Flying!!! here's one of my Heli's
MD500 rc 450Size (4 min 39 sec)
check out my Channel I have 10scaler's
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Old Jul 05, 2014, 05:57 AM
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Tokyo Setagaya-Ku, Japan
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Hi Bad Creation,

Thanks for your great videos! Very realistic flights of great scale helicopters!
And a surprising good airfield!

We could find such good airfields 30 years ago in a neighborhood of Tokyo.
But now almost no places other than small parks in Tokyo;
any RC planes and helicopters are prohibited even in a large riverside in Tokyo.

Indeed when I was enjoying a small RC helicopter Ikarus Piccolo for one hour
in some large riverside, some guard of the river came to us and told us
that any RC flights are prohibited here. (Even though there were almost nobody
near us ).

So our recent flight style is : enjoy one or two flights and run away!

K2-tokyo

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Originally Posted by Bad Creation View Post
I understand where your coming from definitely want to spend more time Flying!!! here's one of my Heli's https://www.youtube.com/watch?v=AEMiB8EX2mo check out my Channel I have 10scaler's
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Old Jul 06, 2014, 08:55 AM
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WOW that Sucks thank you for your Comment on my Video's
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Old Jul 17, 2014, 01:53 AM
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hello K2
you always seem to do very interesting (and innovative) work.
I remember when you bought a G400 at release time, with a plan to use the fbl controller for a scale project. Pleased to see you made the idea a reality.
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Old Jul 17, 2014, 06:45 PM
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Hi, mono

Thank you for your interests.
Yes, my purpose is applications of recent cheap but good devices; I cannot afford 500~1000-dollar devices.

Quote:
Originally Posted by mono View Post
hello K2
you always seem to do very interesting (and innovative) work.
I remember when you bought a G400 at release time, with a plan to use the fbl controller for a scale project. Pleased to see you made the idea a reality.
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