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JR XG11 Programming for Retract and Gear doors

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Old 09-16-2018, 02:36 PM
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barnowljenx
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Default JR XG11 Programming for Retract and Gear doors

Another puzzle for that genius Alan Worrest.

Hi, I'm just about to start building a Top Flite P51 1/7 scale and would like to make and use the inner u/c doors. They are required to open to allow the u/c to extend and then close. On retraction, they are required to open, let the u/c retract and then close.

My question is, is there a way in which the XG 11 can be programmed to achieve this using separate channels for gear doors and the u/c? There is a sequencing gizmo that is available from Hobby King that says it will operate in this way but just wondered if the Tx has the ability to do it.

Thanks.
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Old 09-19-2018, 09:58 AM
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AWorrest
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The standard response to your question is to use the SERVO SPEED menu in the Function List. First in the Device Select set both the GEAR and the gear door channel [DEVICE] to the same switch, preferably the MIX SW as it is two-position. In the SERVO SPEED menu, set the gear door channel opening rate to NORM while the closing rate is set to a very slow setting. Do the opposite for the GEAR rates. Set the extend rate to a slow value and the retract rate to NORM.

If you use retract servos instead normal proportional servos for both the gear and the doors, the effect is more realistic as servo speed in opening and closing the doors or extending and retracting the gear is set by the servo and not by the transmitter. The SERVO SPEED menu settings determine when the non-proportional retract servos start to move.

Iíve never had gear doors on my planes that used retracts. As an experiment on my desk I connected two JR NES-703 retract servos to a receiver, one for the doors and the other for the gear. The gear extend rate and the door closing rate were set to 4.78 sec/60 degrees. The door servo would open up completely before the gear servo started to extend. Conversely, the gear servo would be completely in the retracted position before the gear door servo started to close.

If you use JR retract servos, be aware that some (if not all) were designed run on a maximum of 4.8 volts. Reports Iíve read is that they wonít function using higher voltage. JR made a voltage reducer device for their retract servos.

Allan
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Old 09-20-2018, 03:11 AM
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barnowljenx
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Allan

Thank you so much for that advice. However, the problem remains of how to close the doors after the u/c has extended. That is for extending the u/c the doors open, the u/c extends and then the doors close - on retraction, the doors open, the u/c retracts and then the doors close. I had used the servo slow function on just retracts but had not thought about using it to sequence the u/c and doors but on its own it does not operate as per my description above. The alternative is to use an electronic sequencer for carrying out the functions and just use a single channel to trigger the sequencer. I had thought that you might have a function that allowed the full sequencing that I have described. I guess I need to use the sequencer to cover the need to keep the secondary doors closed apart from when the u/c is commanded to extend or retract.

Thanks

Peter
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Old 09-20-2018, 11:57 AM
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With an eleven channel radio, you do not have enough channels to accomplish what you want. A sequencer is going to be your only real solution.
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Old 09-22-2018, 12:10 PM
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AWorrest
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Peter,

I should have read you initial post more carefully. Building upon what I wrote, it is possible to have the gear doors close after the gear has been extended. It requires using a three-position switch to actuate the gear and two curve program mixes in addition to setting up the servo speed menu and the use of retract servos for both the gear and doors. When the gear switch is in position 0, the gear is retracted and the doors are closed. In position 1, the gear doors open and the gear extends. In position 2, the gear remains extended and the doors close. Going in the reverse order from position 2 to 1, the doors open while the gear remains extended. From position 1 to 0, the gear retracts and the doors close.

However, there are a couple conditions that could cause the retract mechanism to rip off the doors. One is if the gear switch is switched from one position to the next before each step’s actions are completed. Another is if the transmitter-to-receiver connection is made with the gear switch not in the position that corresponds to the actual gear and door positions. Overall this scheme requires quit a bit of operator diligence.

If you wish for the doors to close after the gear has extended, a sequencer would require a lot less pilot workload. (I'm still trying to understand Zeeb's comment. With XBus the XG11 can handle 44 servos!)

Allan

Last edited by AWorrest; 09-22-2018 at 12:17 PM.
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