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Jul 15, 2019, 09:00 PM
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mdmyers's Avatar
So I've stripped the aileron servos several times on less than stellar landings as I learned this thing. Typical scenario was coming in too hot or not quite level and tipping on the roll out resulting in blade strike and the resultant shock to the servos through the head and push rods. I ran across the attached suggestion for a helicopter and tried it out and have found it really seems to help. I've had two bad landings recently since doing this and both times, the arms slipped on the servo but no stripped gears! Just had to remove the screw and reset the arm positions and then back to the air and getting better at landings... I've not seen any movement of the arm from normal use.

Blade 180 CFX servo saver mod how to (3 min 25 sec)
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Jul 24, 2019, 07:21 AM
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anyone knows what the RPM is of the rotor in cruising flight mode?
Jul 25, 2019, 05:00 AM
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Analyzing a video of take off and flight of the autogyro, e.g.
https://youtu.be/LbOHnXMEmv0?t=200
I see the rotor spin up.
At 3:32 in the first left turn it seem to come to a halt and then goes backwards. This is an optical illusion as the speed of rotation comes in sync to the frame rate of the video: 30 fps. This corresponds to 1800 pictures per minute. The rotor has three blades. Thus its RPM can be 600, 1200, 1800, 2400, ... in the fast left turn. Somewhere I have read that the Auto-G begins to becomes light at 1000 RPM.
Jul 26, 2019, 03:33 AM
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I am installing a Jeti rpm telemetry sensor , so 'ill know soon!
Jul 29, 2019, 03:38 PM
Build, crash, repeat...
lee292a's Avatar
If I remember correctly, autogyro blades only reach about 500 rpm, whereas rc helicopters are over 1000 rpm. Remember, there's no power going to the blades.
Aug 02, 2019, 08:02 AM
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nothing beats fact and figures. I measured with my telemetry and rpm floats around 1050, remarkably stable and quasi constant versus motor power (hence flight speed), just as theory says. Only in slow descending autorotation I got the impression it went down somewhat (but forgot to put the telemetry voice reporting on, will be next flight)
Aug 02, 2019, 08:05 AM
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And by the way, I noticed (tested on purpose) the 'turn to the right on rudder only and the rotor will tilt to the left' phenomenon. very interesting, I don't understand, need to read some of the theory!
Aug 04, 2019, 05:16 AM
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This thread me be somewhat asleep, but for the sake of documenting additional insights, I keep going
As described I installed RPM telemetry on the rotor. I measured 1050, but found the control input rather challenging. Unless well coordinated between rudder and ailerons, control just did not feel comfortable. The more that when I tested turning rudder only to the right, the gyro flipped to the left!. I keept testing this, could recover , but finally the gyro won and crashed. I put new blades on, and now the rpm was rather 1150. Probably something in the moulding that changed the incidence (will check this later). The point: in flight the control felt even less comfortable. So I decided to increase the blade incidence (less negative) . One way to do that quickly (on the field) is to take out the outboard bolt (no need for that anyway, swivelling blades stretch fine by themselves as in heli), and in my first attempt I turned the plastic incidence wedge at 45 degrees, in a second attempt at 90 degrees (gradually taking out all negative incidence). At 45 flight was way better, at 90 it became an absolute dream. RPM is now at 900rpm. Power consumption at cruising is at least 30% less (I fly 3 cell 1300mAh) It tracks a lot straighter when changing flight speed, and I can turn on rudder only for ever. Ailerons are perfectly reactive both sides (I did put ATV at 25% less to the left though, a CCW rotor will always turn easier to the left) ). I did have to trim the elevator down however, and in landing (at 700rpm) it requires some additional elevator down. But it flares and touches down like a butterfly.
This modification had two effects: the lower rpm at higher incidence seems to be the sweet spot for this aircraft, and because now the blade can tilt up more freely over a larger distance, the rotorhead became far less rigid absorbing better the blade flapping. Just as inventor De la Cierva experienced. a century ago. See pictures, the vertical red thing is the rpm sensor.
It has been described that rudder only does not work, I can only observe mine does.
More to come...
Aug 04, 2019, 02:43 PM
PSALM 14:1
Sammy70's Avatar
Thread OP
Thanks for the update, I may try that on mine


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