I just want to have a single switch and single rc channel to start my heli. How do I disable the motor interlock requirement?
Less ideal but maybe an option, can it be set to a stick position? Sow Collective low then arm?
Or am I stuck with the interlock as a byproduct of the RCS? I am using Ardupilot governor to control rotor speed.
I don’t think so. It is there to prevent your flying murder machine from trying to kill you. There are situations you may want to kill motor without disarming the helicopter.
Thing is, with a multicopter you have throttle control which somewhat reduces the risk of cutting off someone’s fingers after the drone is armed. With a heli you don’t. Without interlock the rotor would spin up to speed immediately after arming.
I guess you could set arm/disarm the traditional way by holding the left stick down-right and set interlock to a switch?
Actually, why don’t you set up a mix on a three-position switch on your Tx where position 0 is disarm/lock, 1 is arm/lock, and 2 is arm/unlock?
That’s what I was getting at. But then decided not to get into the Trade Heli safety related stuff. It brings back bad memories of my buddy flying his 700 into himself causing a gruesome injury to his leg. Not a Arducopter craft.
You can’t remove the interlock requirements. It is hardcoded into the firmware. You could write a Luis script that would do the arming and motor interlock through one RC switch though.
On most multirotor configurations the props turn as soon as its armed but at “idle” and an “idle” or lowest possible stick position for throttle is required when you arm. I dont see this as any less dangerous than a heli especially with configurable throttle ramp up speeds.
“Actually, why don’t you set up a mix on a three-position switch on your Tx where position 0 is disarm/lock, 1 is arm/lock, and 2 is arm/unlock?”
Something like that is what I would like to do. So far I can not figure out how to use a single channel for this in ardupilot though. I could setup a mix on the radio to control 2 RC channel with one switch and I know how to do this. But setting it up to use one RC channel in ardupilot is what I can not figure out.
“I guess you could set arm/disarm the traditional way by holding the left stick down-right and set interlock to a switch?” This is an interesting option. Seems like I would get everything I want by using it then just using the motor interlock switch like I’m used to using the arm switch. In the docs I see that its just supposed to work. Do I just un assign the arm switch and arming with sticks becomes active?
I only use rudder arming and disarming. I have a switch that is for the motor interlock. I think this is the easiest option for you. You should already have rudder arming enabled. Try holding your throttle stick down and to the right to see if it’ll arm the aircraft.
I believe there’s a parameter called arming options that will allow you to enable and disable rudder arming
Thanks, Ill try that out when I get a chance. Do you arm first than motor interlock? I have been doing the interlock first then the arm switch. Coming from more traditional heli flight controllers and quad copters the double arm switches felt weird but that makes more sense the way you are describing it of treating the motor interlock like a normal arm switch and using the sticks before the motor interlock.
This is the answer.
The option for using a single 3-position switch would still occupy two transmitter channels. You’d end up creating a mix to set the arming channel high at the mid position and then the interlock channel high at the end position. It would save you a physical switch, not a channel.
Yes, but, idle RPMs for a medium-large (600) quad will be at ~500RPM. Let’s say it’s a 13" prop. Tip speed is 8.5 m/s.
Now take a heli with 42cm blades at the same RPM. Tip speed now is 22 m/s. Considering the larger diameter and mass, the force of impact would be roughly 10 times as strong with the heli blade. Which could make the difference between cutting your finger and chopping it off.
Sure but it does not turn at idle RPM the instant you bump a switch. Multi rotors do spin up to idle almost instantly and in some flight mods if disturbed the motors can go bazerk with out any input from the transmitter. My only point here is that the accidental starting of motors isn’t particularly more dangerous on heli than other systems that use different safety measures for starting the motors. That said it looks like I am not using these safety measure in the standard way and this has contributed to my own added complexity that I am trying to remove. For sure a already fully revved up heli tends to have a lot more energy and damage potential than sorta comparable multi rotors. But you are not accidentally turning them on in to a fully revved up state on either and that unintentional activation is in my mind what these safety features are intended to prevent.
It seems like all of my “complaints” (not really complaining just trying tinker to make things a little better over time) are caused by me misunderstanding the SOP and just making it hard on my self lol. That’s why its good to ask places like this and just find out from others there are better ways.
Yes, you should always have to arm first. If you don’t then you are overriding some safety feature.
I have 2 switches one for arm and one for interlock I have always been doing the interlock first than arming. Thinking of arming like on other FC where arming is the last step to get thing flying. I’m glad I asked about this because I’m finding out I’m doing the whole process wrong lol.
Thanks for everyone’s input!
One other question about stick disarm, if the motor is running (motor interlock engaged?) and I hold the throttle low and rudder right for 2 seconds will it still disarm?
Also rereading the guides about how to setup the rcs in figuring this out it looks like its possible on an electric heli to have 2 rotor speeds set? Idle and Flight speeds?
" H_RSC_IDLE: Throttle Output at Idle¶
Throttle output (HeliRSC Servo) in percent while armed but motor interlock is disabled (throttle hold on). FOR COMBUSTION ENGINES. Sets the engine ground idle throttle percentage with clutch disengaged. This must be set to zero for electric helicopters under most situations. If the ESC has an autorotation window this can be set to keep the autorotation window open in the ESC. Consult the operating manual for your ESC to set it properly for this purpose"
Sounds like it would be a bad idea but if the rcs_idle is set to something other than zero it will send this setting to the ESC when armed but before motor interlock? With out the gov I am not sure this would be useful but Im interested in how it works anyway. Multiple rotor speeds on a switch would be nice. Something iv tried to look in to a little but not been serious. Still getting this little heli to just work at all. Its a slow dabble for me.
Rudder left to disarm.
As @Yuri_Rage points out disarming is down and to the left. However, you don’t want to do that with the engine on because the controller will command full left rudder which would be disastrous with the motor running.
The idle is for combustion engine heli’s and was never intended to be used as a second rotor speed for electric powered aircraft. In fact, it should always be zero for electrics as there is another idle setting for manual autorotations which allows the user to set it separately. Looks like I need to change the wiki as the RSC IDLE should never be used for manual autos.
Don’t do this. It is a terrible idea.
Currently, the only way you could get multiple rotor speeds for an electric heli or a heli using an external rotor speed Governor would be to use RSC_MODE 1. I generally don’t recommend passthrough as an option but it could be used safely if you ensure the RC receiver failsafe for the motor interlock RC channel is set to hold current value. Otherwise if there was a ttransmitter lost link, the heli would crash because the channel would go low and turn off the motor.
This is a reasonable option for those doing sport flying. You then would set the rotor speed using the motor interlock channel on your TX. However be cautious about setting the channel for a speed where the PWM output would be below 1200. This is the threshold for motor interlock enabled/disabled.
I’d like to add -with safety first in mind- there is no gain scaling when switching between different rotor speeds. Depending on the tune it might be not ideal to use different rotor speeds, as normally we tune (manually or autotune) for a specific rpm setpoint.
I was thinking more inflight if this was something I needed to worry about avoiding this stick position. Like if I had the skills would the heli disarm if I where to stay in an inverted piro for more than 2 sec of fell stick deflection?
My heli is setup for FPV so there might be higher risk of certain stick positions/movements then with more traditional use. Not that I think there is a huge risk here just curious if its something I need to keep the back of my mind to not disarm in flight with stick commands.
Thanks all for letting me bounce these ideas off of you and explaining things!
Yes you can disarm the vehicle in flight if you held the stick down and to the left for more than 2 sec.
If you are worried of accidentally disarming by stick, you can disable the arming rudder logic by setting
ARMING_RUDDER to 0 and use an auxiliary switch instead (set RCx_OPTION to 153).