Autopilot operation with rudder? - ED Forums
 


Notices

Reply
 
Thread Tools Display Modes
Old 07-26-2018, 08:09 AM   #1
WildBillKelsoe
Veteran
 
WildBillKelsoe's Avatar
 
Join Date: Jun 2009
Location: Cairo, Egypt
Posts: 6,221
Default Autopilot operation with rudder?

Do I trim for course, keep leg on rudder, then engage heading hold, then remove my feet off rudder?
OR
Do I trim for course and all the above AND keep my leg on rudder too?

Also what does the red button thing for rudder autopilot testing do? How should it be set before takeoff? Does it alleviate the need for foot on pedals?
__________________
AWAITING ED NEW DAMAGE MODEL IMPLEMENTATION FOR WW2 BIRDS

Fat T is above, thin T is below. Long T is faster, Short T is slower. Open triangle is AWACS, closed triangle is your own sensors. Double dash is friendly, Single dash is enemy. Circle is friendly. Strobe is jammer. Strobe to dash is under 35 km. HDD is 7 times range key. Radar to 160 km, IRST to 10 km. Stay low, but never slow.
WildBillKelsoe is offline   Reply With Quote
Old 07-26-2018, 10:16 PM   #2
AlphaOneSix
Veteran
 
AlphaOneSix's Avatar
 
Join Date: Sep 2006
Posts: 2,970
Default

Quote:
Originally Posted by WildBillKelsoe View Post
Do I trim for course, keep leg on rudder, then engage heading hold, then remove my feet off rudder?
This.

Quote:
Originally Posted by WildBillKelsoe View Post
Also what does the red button thing for rudder autopilot testing do? How should it be set before takeoff? Does it alleviate the need for foot on pedals?
Are you talking about the tail rotor pitch limit system (SPUU-52)? If so, that system has absolutely nothing at all to do with the autopilot system whatsoever.

Okay, I'm lying. They work together in the sense that the autopilot, even though it has 100% authority in the yaw channel, will not push beyond the pitch limit set by the pitch limiting system. But for all practical purposes, they have nothing to do with each other.

The only other red button is the one under the green one for the yaw channel, and it just turns the yaw channel off.
AlphaOneSix is offline   Reply With Quote
Old 07-27-2018, 04:11 PM   #3
WildBillKelsoe
Veteran
 
WildBillKelsoe's Avatar
 
Join Date: Jun 2009
Location: Cairo, Egypt
Posts: 6,221
Default

see my problem is removing my feet while heading hold is engaged causes the helo to act. I am taljing also about the red button above the radio on the pedestal.
__________________
AWAITING ED NEW DAMAGE MODEL IMPLEMENTATION FOR WW2 BIRDS

Fat T is above, thin T is below. Long T is faster, Short T is slower. Open triangle is AWACS, closed triangle is your own sensors. Double dash is friendly, Single dash is enemy. Circle is friendly. Strobe is jammer. Strobe to dash is under 35 km. HDD is 7 times range key. Radar to 160 km, IRST to 10 km. Stay low, but never slow.
WildBillKelsoe is offline   Reply With Quote
Old 07-27-2018, 08:58 PM   #4
thrustvector
Member
 
thrustvector's Avatar
 
Join Date: Dec 2017
Location: Exeter uk
Posts: 635
Default

when using the heading hold, with warthog stick for example, trim to heading press and let go sometimes there is a slight movement but try an make sure you are nearly trimmed to the heading you want first so the AP can take over, remember its only about 20% authority (may be a bit wrong there please correct )
red button centre console?
thrustvector is offline   Reply With Quote
Old 07-28-2018, 05:10 AM   #5
AlphaOneSix
Veteran
 
AlphaOneSix's Avatar
 
Join Date: Sep 2006
Posts: 2,970
Default

The red button above the radio on the pedestal sounds like the on/off button for the tail rotor pitch limiter which is not the autopilot yaw channel.

The yaw channel has 100% authority. The other channels only have 20% authority.

When the yaw channel is engaged (green light is illuminated for the yaw channel on the autopilot control desk) and you remove your feet from the pedals, it should begin to move the pedals as required to maintain the heading at which the feet were removed from the pedals.
AlphaOneSix is offline   Reply With Quote
Old 07-28-2018, 08:34 AM   #6
WildBillKelsoe
Veteran
 
WildBillKelsoe's Avatar
 
Join Date: Jun 2009
Location: Cairo, Egypt
Posts: 6,221
Default

Ok that confirms it then guys. So that tail rotor pitch limiter has nothing to do with autopilot rudder authority. Why is it there?
__________________
AWAITING ED NEW DAMAGE MODEL IMPLEMENTATION FOR WW2 BIRDS

Fat T is above, thin T is below. Long T is faster, Short T is slower. Open triangle is AWACS, closed triangle is your own sensors. Double dash is friendly, Single dash is enemy. Circle is friendly. Strobe is jammer. Strobe to dash is under 35 km. HDD is 7 times range key. Radar to 160 km, IRST to 10 km. Stay low, but never slow.
WildBillKelsoe is offline   Reply With Quote
Old 07-28-2018, 08:44 AM   #7
lucky-hendrix
Member
 
Join Date: Nov 2006
Posts: 119
Default

Quote:
Originally Posted by WildBillKelsoe View Post
Ok that confirms it then guys. So that tail rotor pitch limiter has nothing to do with autopilot rudder authority. Why is it there?
It changes the the relationship between pedal angle and tail rotor pitch. So that for every altitude/pressure the pilot has to put the same amount of pedal to go into hoover.

It doesn't translate well into the sim because of the way the rudder trim and heading AP works

Sent from my VTR-L09 using Tapatalk
lucky-hendrix is offline   Reply With Quote
Old 07-29-2018, 01:09 AM   #8
AlphaOneSix
Veteran
 
AlphaOneSix's Avatar
 
Join Date: Sep 2006
Posts: 2,970
Default

Quote:
Originally Posted by lucky-hendrix View Post
It changes the the relationship between pedal angle and tail rotor pitch. So that for every altitude/pressure the pilot has to put the same amount of pedal to go into hoover.
That's not true at all. I apologize for being so blunt. The relationship between the pedal locations and the corresponding tail rotor pitch will always be the same. Likewise, different atmospheric conditions could result in different pedal positions in a hover as the main rotor requires more or less pitch to maintain a hover.

Also, as I've mentioned before, the tail rotor pitch limiter is a completely separate system from the trim and autopilot systems and doesn't interface with them at all except to momentarily disable the yaw autopilot when a "pitch limited" condition occurs.

The purpose of the tail rotor pitch limiter is to limit the amount of pitch you can safely put into the tail rotor. I hate that I have to type it like that since it seems like I'm just retyping the name of the system. But I think it bears emphasizing.

Anyway, the tail rotor pitch limiter cannot move the pedals or put pitch into or out of the tail rotor blades. It works by sensing the ambient air temperature and pressure, and then moving a spring-loaded stop closer to or further away from a spring cartridge on the flight control rod that connects to the yaw hydraulic servo actuator. The "spring-loaded" stop is just there so that if the stop comes into contact with the spring cartridge, it disables the yaw autopilot channel until they come back out of contact. Just like the microswitches on the pedals. Also, when the stop is in contact with the spring cartridge, the pilot must overcome the spring pressure in the spring cartridge in order to push the pedal more to the right. The whole purpose of this is to warn the pilot not to exceed certain tail rotor blade pitch settings at lower altitudes/cooler temperatures. The location of the stop corresponds to the white vertical bar in the sight window on the pitch limiter control panel. When the bar is all the way to the left, the stop is fully retracted and will not contact the spring cartridge on the flight control rod before the pedals hit their own built-in stop. This means that the pitch limiting system is not limiting pitch at all in this circumstance. As the white bar moves to the right, the stop is coming closer and closer to the spring cartridge on the yaw flight control rod. With the stop fully retracted, you can push the pedal to it's full right limit, corresponding to a tail rotor blade pitch angle of 23°20’. With the stop fully extended, you cannot push the pedals all the way to the right unless you "push past" the force of the spring on the spring cartridge. In this case, the tail rotor blade pitch angle is limited to 17°20’, although you can force the pedals through the spring force and get the full pitch in an emergency.
AlphaOneSix is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

All times are GMT. The time now is 02:42 AM. vBulletin Skin by ForumMonkeys. Powered by vBulletin®.
Copyright ©2000 - 2018, Jelsoft Enterprises Ltd.