Max RPM confusion or glitch.

[Vanamonde]

Changing the max RPM setting in the SPH 

does not change the max RPM setting when you fly the craft. 
 

Or am I confused about how these are supposed to work? 

[mystifeid]

Out of about twenty aircraft, this happens to just one - a single engine plane. The rest have the rpm limit applied on launch. With the single engine plane, if I replace the engine the rpm limit is then applied in launch. If I use just two parts - a pod and an engine - the rpm limit is applied on launch. So far I've tried quite a few things but haven't been able to reproduce it.

[AHHans]

Are you using a KAL-1000 controller? Its settings overwrite anything you set in the VAB. (Well, technically "update" not "overwrite"...)

[Vanamonde]

No controller. And I've noticed that when I try to lower the RPM max in flight, the slider instantly jumps back to full again as soon as I let go of it. 

[mystifeid]

Do you have rpm limit assigned to the main throttle keys?

This is the only way I can reproduce this behaviour. It does not appear to be a bug since by default we launch at full throttle. The rpm limit slider bounces after dragging because the throttle is maxed. But the throttle keys work - ie the throttle controls the sliders but not vice versa.

Interesting that I have only one plane left with anything assigned to the main throttle keys - normally nothing is assigned to these keys and this is just one more reason not to do it. (Along with fine control not working with the throttle keys)

Edited August 6, 2019 by mystifeid

[Vanamonde]

I do use throttle for RPM, but if I set the part max in the SPH, then 100% throttle should only be the max I've set before flight, right? Like thrust limiter on rockets? 

[mystifeid]

Apparently not. Try using custom axis groups for rpm limit, torque limit and propeller pitch. Then you can do what you want.

[Loskene]

Binding the RPM limit to an axis binds the full unrestricted range regardless of what you set it to in the VAB, 100% throttle is read as 100% RPM limit, same for torque. I got around this using a KAL with the start/end points set to the range limit I want and binding the KAL's play position to the throttle, that way it only does 0-100% of whatever's in between the two timeline points, rather than the complete range of the slider. This works for any slider you want to enforce a range limit on, I also use it for prop blade pitch angle because the default deflection range is enormous and makes them fiddly to control by eye.

Edited August 7, 2019 by Loskene

[mystifeid]

1 hour ago, Vanamonde said:

Like thrust limiter on rockets? 

If you assign thrust limit to the main throttle keys the same thing happens to a rocket engine.

11 minutes ago, Loskene said:

I also use it for prop blade pitch angle because the default deflection range is enormous and makes them fiddly to control by eye.

Try assigning to custom axis groups and then using fine control (caps-lock). You will be surprised at the difference.

[Vanamonde]

Well, that's annoying. Thanks, people.