Orbiter-Forum  

Go Back   Orbiter-Forum > Orbiter Addons > Addon Support & Bugs > Addon Developer Forums > Space Shuttle Ultra
Register Blogs Orbinauts List Social Groups FAQ Projects Mark Forums Read

Space Shuttle Ultra Support & development threads for Space Shuttle Ultra addon.

Reply
 
Thread Tools
Old 12-13-2018, 05:38 PM   #2146
Abdullah Radwan
Addon Developer
Default

Now I have a fully working landing gear deploy system as described in SCOM. Now time to work on the brake system.

I want to know where the brake system is defined in the code. I only found this code:
Code:
SetMaxWheelbrakeForce(250000 / 2);
Abdullah Radwan is offline   Reply With Quote
Old 12-13-2018, 05:52 PM   #2147
GLS
Addon Developer
 
GLS's Avatar
Default

Quote:
Originally Posted by Abdullah Radwan View Post
 Now I have a fully working landing gear deploy system as described in SCOM. Now time to work on the brake system.
Care to point out what was missing, and why is it needed to simulate the hydraulic system?

Quote:
Originally Posted by Abdullah Radwan View Post
 I want to know where the brake system is defined in the code. I only found this code:
Code:
SetMaxWheelbrakeForce(250000 / 2);
We don't have brakes... we use Orbiter's "braking system".
GLS is online now   Reply With Quote
Old 12-13-2018, 06:21 PM   #2148
Abdullah Radwan
Addon Developer
Default

Quote:
Originally Posted by GLS View Post
 Care to point out what was missing, and why is it needed to simulate the hydraulic system?
What I did is separating the gears, and assigning hydraulic systems for each gear. I forget to mention that I haven't programmed the pyrotechnics yet.


What is the deploying speed for pyrotechnic deploy?
Quote:
Originally Posted by GLS View Post
 We don't have brakes... we use Orbiter's "braking system".
Is there a way to set brakes for the 2 main gear only? Or a 'from scratch' breaking system should be created?



And what about the nose wheel steering?
Abdullah Radwan is offline   Reply With Quote
Old 12-13-2018, 06:34 PM   #2149
Donamy
Beta Tester


Default

Quote:
Originally Posted by Abdullah Radwan View Post
 What I did is separating the gears, and assigning hydraulic systems for each gear. I forget to mention that I haven't programmed the pyrotechnics yet.


What is the deploying speed for pyrotechnic deploy?


Is there a way to set brakes for the 2 main gear only? Or a 'from scratch' breaking system should be created?



And what about the nose wheel steering?

This is all well and good, ...but, and this is JMO. What we need is, someone to help take some of the workload off of GLS, to finish things that are already being worked on, so we can get a release for SSU 5.0.

So if you can do both, work on the things you are interested in and helping GLS. That would be a huge help. If not, that ok too.


BTW welcome to the team.
Donamy is offline   Reply With Quote
Thanked by:
Old 12-13-2018, 06:50 PM   #2150
GLS
Addon Developer
 
GLS's Avatar
Default

Quote:
Originally Posted by Abdullah Radwan View Post
 What I did is separating the gears, and assigning hydraulic systems for each gear. I forget to mention that I haven't programmed the pyrotechnics yet.


What is the deploying speed for pyrotechnic deploy?


Is there a way to set brakes for the 2 main gear only? Or a 'from scratch' breaking system should be created?



And what about the nose wheel steering?
Are the gear and brake isolation valves done? And the MPS/TVC ones? What about the heat going in from the pumps and going out thru the WSB? Hydraulic quantities?

The implementation of the gear, brakes and NWS needs work, but what we have works for now. Same for the ATVC and the ASA. What we need first is an actuator that receives an electrical signal and outputs a position between 0 and 1, and does so taking into account the hydraulic pressures of the systems connected to it. And in the hydraulic system "feels" the flow rate demands of the moving actuators and the pressure varies accordingly.

---------- Post added at 06:50 PM ---------- Previous post was at 06:44 PM ----------

Quote:
Originally Posted by Donamy View Post
 This is all well and good, ...but, and this is JMO. What we need is, someone to help take some of the workload off of GLS, to finish things that are already being worked on, so we can get a release for SSU 5.0.

So if you can do both, work on the things you are interested in and helping GLS. That would be a huge help. If not, that ok too.


BTW welcome to the team.
In no way are not adding more to the 5.0 plate... it's already impossible to release it this year as I wanted.
As far as I can see there are 2 long poles in this tent: finishing the entry code, and finishing the mesh changes. The first is for me to do (unless someone wants to verify the aero code.... lots of numbers and math), the second probably is long enough that I'll have to help on the more boring portions.
GLS is online now   Reply With Quote
Old 12-13-2018, 08:25 PM   #2151
Abdullah Radwan
Addon Developer
Default

Quote:
Originally Posted by Donamy View Post
 This is all well and good, ...but, and this is JMO. What we need is, someone to help take some of the workload off of GLS, to finish things that are already being worked on, so we can get a release for SSU 5.0.

So if you can do both, work on the things you are interested in and helping GLS. That would be a huge help. If not, that ok too.


BTW welcome to the team.
I wish if I can help, but they are working on very complex things. I am a beginner in all sides (Math, physics, programming, space, space shuttle). You can see how I am spending a lot of time to implement a very simple gear system


Quote:
Originally Posted by GLS View Post
 Are the gear and brake isolation valves done? And the MPS/TVC ones? What about the heat going in from the pumps and going out thru the WSB? Hydraulic quantities?

The implementation of the gear, brakes and NWS needs work, but what we have works for now. Same for the ATVC and the ASA. What we need first is an actuator that receives an electrical signal and outputs a position between 0 and 1, and does so taking into account the hydraulic pressures of the systems connected to it. And in the hydraulic system "feels" the flow rate demands of the moving actuators and the pressure varies accordingly.
I guess I was hasty when I said I've done it like SCOM. What I did is just a basic implementation. Nothing was implemented from what you said



Anything that involves a high-level physics or math is very hard to do for me. Like the flow rate and temperature. My physics and math are really awful.


I think if I can understand the theory right, I might be able to do it.


The current gear actuator receives the command from PreStep(After setting gear action to OPENING or CLOSING). It receives the target position (1 for extending, 0 for retracting) and moves the animation until the position is same as the target, then it sets the gear action to OPEN or CLOSE.


As my math is bad, the gear speed is calculated via ratio, assuming the speed is 0.3 with 3000 pressure. The maximum speed is 0.3. All of this is done before multiplying the speed in simdt. I am not sure what I am doing is right, as I've never worked with hydraulics before.


The actuator uses hydraulic system 1 for calculations. If it was the nose gear, it'll use system 2 instead if system 1 pressure was below 1500.

---------- Post added at 10:25 PM ---------- Previous post was at 09:09 PM ----------

I've tried a test flight and always have a hold on T-4 minutes. Where is the hold code?
Abdullah Radwan is offline   Reply With Quote
Old 12-13-2018, 08:31 PM   #2152
Donamy
Beta Tester


Default

You have to turn on the APUs.
Donamy is offline   Reply With Quote
Old 12-14-2018, 06:47 AM   #2153
Abdullah Radwan
Addon Developer
Default

I've followed the checklist and had them running. I want to see the source code to know what is the problem.

---------- Post added 14th Dec 2018 at 08:47 AM ---------- Previous post was 13th Dec 2018 at 10:32 PM ----------

I've solved the problem. The APU speed random sets a low speed that sets a low hydraulic pressure. I've changed the random rate.

Now I am having a hold at T-9.5 seconds. This because SSMEs aren't ready. I don't think I've done any changes to SSMEs. Maybe a hydraulic problem? The hydraulic pressure is stable at 3000.
Abdullah Radwan is offline   Reply With Quote
Old 12-14-2018, 08:33 AM   #2154
Urwumpe
Certain Super User
 
Urwumpe's Avatar

Default

Quote:
Originally Posted by Abdullah Radwan View Post
 I've followed the checklist and had them running. I want to see the source code to know what is the problem.

---------- Post added 14th Dec 2018 at 08:47 AM ---------- Previous post was 13th Dec 2018 at 10:32 PM ----------

I've solved the problem. The APU speed random sets a low speed that sets a low hydraulic pressure. I've changed the random rate.

Now I am having a hold at T-9.5 seconds. This because SSMEs aren't ready. I don't think I've done any changes to SSMEs. Maybe a hydraulic problem? The hydraulic pressure is stable at 3000.

Remember we have no telemetry yet that could be used to read the hydraulic system data independent of what you are implementing. Its well possible, that the LCC checks different variables as you are working with.
Urwumpe is offline   Reply With Quote
Old 12-14-2018, 08:45 PM   #2155
GLS
Addon Developer
 
GLS's Avatar
Default

I still would like to know what work is going on exactly... if we don't have the flow rate demands vs pressure, capability to have different command sources on the actuators, different dP and position measurements, hyd system supplies, isolation valves, etc, then I don't know the point of this.

---------- Post added at 08:45 PM ---------- Previous post was at 08:41 AM ----------

Did anyone by any chance save this document with shuttle aero data? 19850070642_1985070642.pdf
Digging old threads it appears that is where our aero data came from, but it is no longer available online. I found (what appears to be) a similar one, but it dates from 1980, so it only has pre-flight data, thus it's hard to check the data. At least the formulas should be good, so I can check that part (already found the speedbrake input is not correct).

Also, if anyone wants to look at the aero lookuptables and files, and come up with a faster loading system (switch to binary?), be my guest.
GLS is online now   Reply With Quote
Thanked by:
Old 12-14-2018, 08:58 PM   #2156
indy91
Addon Developer
Default

Quote:
Originally Posted by GLS View Post
 Did anyone by any chance save this document with shuttle aero data? 19850070642_1985070642.pdf
Digging old threads it appears that is where our aero data came from, but it is no longer available online.
https://web.archive.org/web/20100512...1985070642.pdf

Most of old NTRS was saved this way. You have no idea how many Apollo documents we could (and had to) recover this way... Just doesn't work for any documents added to NTRS after 2011.
indy91 is online now   Reply With Quote
Thanked by:
Old 12-14-2018, 09:54 PM   #2157
GLS
Addon Developer
 
GLS's Avatar
Default

Quote:
Originally Posted by indy91 View Post
 https://web.archive.org/web/20100512...1985070642.pdf

Most of old NTRS was saved this way. You have no idea how many Apollo documents we could (and had to) recover this way... Just doesn't work for any documents added to NTRS after 2011.
Thanks!!!
It took a few attempts to download it, but I got it after all!
Actually I download most NTRS stuff from archive.org, as they don't put the link in the first page of the document, but I didn't remember of the wayback machine...
GLS is online now   Reply With Quote
Old 12-15-2018, 07:36 AM   #2158
Abdullah Radwan
Addon Developer
Default

Quote:
Originally Posted by GLS View Post
 I still would like to know what work is going on exactly... if we don't have the flow rate demands vs pressure, capability to have different command sources on the actuators, different dP and position measurements, hyd system supplies, isolation valves, etc, then I don't know the point of this.
What I've made is exactly as you said. I didn't make any primary changes. Just separating the hydraulic system from the APU and some minor changes. This should provide a base for further changes.


I am now working on the flow rate. I'll use Ohm's law with flow instead of current, and pressure instead of voltage. The problem is that I don't know what is the resistance. Assuming a normal flow of 21 gpm at 3050 psi, the resistance will be 145.24. Is this right?


So now I have the flow rate. I don't understand how to distribute it between systems. A little bit of explanation here would be great.


As the aerosurfaces will change in Orbiter Beta, I won't deal with it for now.


The current 'working' actuator is the landing gear. It's exactly as you've said. It receives a position from 1 to 0 and moves the gear. The gear speed is calculated based on the pressure (I guess I should be based on the flow).


I want an explanation of " different dP and position measurements, hyd system supplies". I am not sure what this means.


I'll look into the isolation valves after finishing the flow rate and temperature.
Abdullah Radwan is offline   Reply With Quote
Old 12-15-2018, 08:03 PM   #2159
GLS
Addon Developer
 
GLS's Avatar
Default

This might be of use: RSB axis angle to Z-axis = 34.833134 (as indicated in the aero data book)
GLS is online now   Reply With Quote
Reply

  Orbiter-Forum > Orbiter Addons > Addon Support & Bugs > Addon Developer Forums > Space Shuttle Ultra


Thread Tools

Posting Rules
BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts
Forum Jump


All times are GMT. The time now is 11:42 PM.

Quick Links Need Help?


About Us | Rules & Guidelines | TOS Policy | Privacy Policy

Orbiter-Forum is hosted at Orbithangar.com
Powered by vBulletin® Version 3.8.6
Copyright ©2000 - 2018, Jelsoft Enterprises Ltd.
Copyright 2007 - 2017, Orbiter-Forum.com. All rights reserved.