Attitude MFD request

[polaris149Tiberius]

Hi guys,

Ive been trying to immitate the Space Shuttle Launch program and I have been using AttitudeMFD to roll to the desired azimuth. The problem is AttitudeMFD only rolls at a rate of about 1.50* per second. This turns out to make the roll program take too long and by the time the roll to my azimuth is finished, about 90 seconds have gone by and this is too long for the orbit I am trying to make. The real shuttle rolls at about 5.00* per second.
I was wondering if somone could see about adding a rate setting button to the MFD so we can controll the rate AttitudeMFD makes it's changes to the attitudes we are setting. Just to add, the shuttle in Orbiter can roll at 5.00* per second with no problem.

Thanks in advance if anyone can help with this.

 

[tblaxland]

AttitudeMFD has the rotation rates hard coded in at present. Version 3.2 has the rotation rate set at 5deg/s for an attitude error greater than 10deg. From 10deg to 0deg, the rate scales linearly from 5deg/s to 0deg/s.

It is on my "to do" list to make a config file for these settings but I have not had a lot of time for AttitudeMFD development lately.

Notwithstanding the above, it is important to note that AttitudeMFD will rotate the vessel using the vessel's defined rotation thruster groups. This means you will be trying to rotate the entire launch stack using the shuttle's relatively weak RCS thrusters. I have some doubt that the RCS thrusters would have sufficient thrust to accelerate the stack up to 5deg/s.

In real life, the roll program is implemented using thrust vectoring of the SRB nozzles. Depending on which shuttle addon you are using, I believe flying the vehicle manually by keyboard/joystick will roll the vehicle via thrust vectoring. You can still use AttitudeMFD to tell you when you have rolled the correct amount. Alternatively, you may want to look at Launch Compass or [ame="http://www.orbithangar.com/searchid.php?ID=2802"]LaunchMFD[/ame] (which incorporates Launch Compass along with some other very useful tools).

 

[Andy44]

+1 on using Launch MFD with the compass function. Since you are launching manually anyway, may as well do the roll yourself.

 

[polaris149Tiberius]

Thanks for the help

Well I was hoping for an automated function that would roll the Shuttle Atlantis (default shuttle in orbiter 2006)to the correct azimuth. I can roll to the correct azimuth using AttitudeMFD or LaunchMFD manually of course, but I thought since the roll program was automated in real life that this community could come up with an automated roll program which Attitude MFD does but its just too slow. By the time it rolls me to the correct azimuth, Im too high to get into a low orbit say around 150km. I mean I guess I could pitch up super early, but I was really hoping to get a roll program done (automated) by around 52s after liftoff.

I sure wish we could come up with this because I know for a fact I can manually roll at the speed I want to roll too, but the AttitudeMFD takes a very long time to roll to the azimuth that I am able to see for an ascending azimuth in LaunchMFD.

I realize the roll speed is hard coded into AttitudeMFD but maybe we can contact the author of AttitudeMFD and ask if we can make some changes to his code to add this feature. How hard would it be to contact them.

According to Orbiterwiki there were 3 different authors for these different versions which tells me that the original author isnt very strict about his code being modified. Here are the authors: (anyone know these ppl?):

Original Author: Chris Knestrick
V3 by: Bob Denny
V3.1 & V3.2 by: Tim Blaxland

in the orbiter wiki information for this MFD it mentions that:
"Being a strong believer in Open Source, the source files for the MFD are included in the download. You are free to use, modify, and redistribute the code within certain, fairly loose, guidelines. Please read Copyright.txt that is included with the source files for full details. "

So I say to the dev people of these forums:
"Help me Obiwan Kenobi, your my only hope"

 

[Andy44]

Well in real life the whole launch is automated, so if you want to automate the roll, why not just use a full autopilot?

In any case, there's another intermediate solution for you: Set up the Attitude MFD for your desired roll, but don't activate it. Instead, just use the joystick to do the roll yourself, while watching the MFD and driving the error numbers towards zero. The MFD will guide you, but you can get there faster.

 

[tblaxland]

...an automated roll program which Attitude MFD does but its just too slow.

See my comments above for why it is too slow.

Here are the authors: (anyone know these ppl?):

Original Author: Chris Knestrick
V3 by: Bob Denny
V3.1 & V3.2 by: Tim Blaxland

Tim Blaxland is me (see my handle: tblaxland). I also wrote the OrbiterWiki article. I don't know of anyone else currently working on AttitudeMFD nor do I know of any releases by anyone else. I took over development from Bob Denny, who in turn took over from Chris Knestrick.

An automated roll program for the shuttle has been developed by the community, just not for the default Atlantis. David413's ShuttleFleet and Space Shuttle Ultra both have ascent autopilots that incorporate the roll program. These autopilots can take you all the way to MECO if you desire but they can also be terminated after the roll program if you prefer to fly your own pitch program. There doesn't seem to be sufficient demand for a similar autopilot for the default Atlantis given the popularity of the aforementioned addons. Note that because the autopilot would have to use thrust vectoring it would be vessel specific, not generic like AttitudeMFD.

One final comment: the roll program is actually a combined pitch and roll program but one of the shuttle gurus can probably give you more details.

 

[Urwumpe]

One final comment: the roll program is actually a combined pitch and roll program but one of the shuttle gurus can probably give you more details.

Yes, the guidance on most rockets actually orient the rocket along the desired flight vector. For the shuttle, the maneuver starts as a tiny yaw maneuver, and ends as pitch maneuver from the view of the Shuttle, when the shuttle oriented itself to the right LVLH attitude with 180° Bank.

Additionally, the shuttle does actually have to pitch AND yaw while banking during ascent, as there is a huge difference between the thrust vector and the vessel axis. Rotating around the vessel axis would create higher forces, which together with winds, could make the Shuttle loose a few parts.

 

[desertman]

tblaxland, any chance you could add a feature that would adjust pitch to hold a given ascent/descent rate? Forgive me if the question is outside the scope of this MFD.
Just wondering.

Ted

 

[n0mad23]

Set up the Attitude MFD for your desired roll, but don't activate it. Instead, just use the joystick to do the roll yourself, while watching the MFD and driving the error numbers towards zero. The MFD will guide you, but you can get there faster.

This is how I use AttitudeMFD for rotation, and it does get you there considerably faster. I tend to use MFDs as visual guidance systems whenever possible, and do as much manual activity as possible.

 

[tblaxland]

tblaxland, any chance you could add a feature that would adjust pitch to hold a given ascent/descent rate? Forgive me if the question is outside the scope of this MFD.
Just wondering.

Ted

This has been asked before, and yes, I feel it is outside of the scope of this MFD (at least for now).

Computerex's Autohover MFD has some handy autopilots in it, including pitch hold and vertical velocity hold. I have not tried it myself.

 

[DaveS]

Would it be possible to add a config screen for AttitudeMFD, with options for deadbands and rates?

 

[tblaxland]

Would it be possible to add a config screen for AttitudeMFD, with options for deadbands and rates?

Currently planned but not yet in work.

 

[polaris149Tiberius]

My Bad

I have been using the AttitudeMFD 3.0 and not 3.2. AttitudeMFD v3.2 rolls at a rate of about 4.22*/s and that has been fast enough to get me to the correct azimuth that I wanted in time which was the ascent Inclination I wanted. I didnt know about the new version of AttitudeMFD so I guess its my bad.

I just want to add that AttitudeMFD 3.2 is AWESOME!!! It is exactly what I wanted the old Attitude 3.0 to do. Sorry that I didnt check out 3.2 earlier before this thread was posted. I guess being out of the loop for so long has made me a bit out of date sort to speak.

Sorry for any inconvienance. tblaxland you are a scholar and a gentleman for replying to my thread. I very much appreciate your time and attention to what is now an obsolete thread.

Again my extream thanks to the dev guys and everyone else who responded to this thread. You guys are the greatest!!!!!

Thanks guys this is what I and Im sure others wanted.