Problem Althold.... in 4.0

Is you protos electric or gas power heli? What output channel on the pixhawk is the ESC or throttle servo connected?

It appears by looking at your param file that you don’t have the HeliRSC (SERVOn_FUNCTION = 31) set for any of the output channels.

For your 3.6.12 setup, what is the channel that is set for the ESC/Throttle Servo?

One more thing. You have your Arming checks off. I was wondering how it was allowing you to fly without a servo set for heliRSC.
Did you intentionally set ARMING_CHECK = 0?

Hello Bill,
it is electric. i have ch 8 for the trottle. but not HeliRSC, it ist RC through. But the ch8 gets a positve signal when switching on the motor. in 3.6 I had seen, that that was required for althold.

From beginnig I had arming_Check = 0, and the tandem and the protos are flying correct in all modes in 3.6


I want to help you but if you can’t use the software how it is designed to be used then I can’t help you anymore. You are wasting my time by having me look into problems that you caused by intentionally not setting up the system the way it is designed.
I think you have a great project but I can’t help you until you start using the software the way it is designed.

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Hello Bill,
I understand you of course. However, I did not understand the instructions so that it is only possible with HELIRSC, but also with RCTHROUGH.
In 3.6 that works fine. And a reference to the necessities when switching to 4.0 would be helpful.

My friend has 4.0 and also HELIRSC, and it worked.

But: on his last flight in RTL (which he often did), FC disarmed at 8m and switched off the engine. Fortunately, the damage was minimal.
There was no error in the logs, the height was displayed correctly.

I don’t want to fly my 20kg tandem with this risk.

So I’m sticking to 3.6 for now.

I would like to thank you and Felix again for the support, in other respects it helped a lot.
And I will definitely have a question again in the future …

Best regards, Holger

Here are my requirements before I will move forward helping you.
You must set ARMING_CHECK to 1.
You must set SERVO8_FUNCTION to 31.
You can use the RC passthrough mode of the Rotor speed control (H_RSC_MODE = 1) however I do NOT recommend it. If you are using an electric engine, then set H_RSC_MODE = 2 which is RSC Setpoint mode. You’ll set the H_RSC_SETPOINT to the percentage of the throttle for the corresponding motor output.

I don’t know the details of your friend’s setup. if he wants to post his log in a separate post then I can look into why it disarmed (I would like to know in case there is an inherent problem with the code). But the RC Passthrough mode of the RSC is not recommended if you are doing autonomous flights because, if you lose the RC transmitter connection, then it is possible that the engine will shut off. The other RSC modes protect against that.

One more thing. You are putting your aircraft more at risk by not having Arming Checks on than using the system as designed.