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Old 12-11-2018, 10:38 AM   #2131
Abdullah Radwan
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I detected the bug and fixed it. It works now.

Now hydraulic actuators for elevon, rudder, speed brake, and body flap are implemented.
For now, the hydraulic system is very simple and doesn't simulate the temperature and flow rate. It just an APU that controls the pressure for the system.

Any idea about implementing temperature? How I can set the temperature and change rate?
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Old 12-11-2018, 11:03 AM   #2132
Urwumpe
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Quote:
Originally Posted by Abdullah Radwan View Post
 Any idea about implementing temperature? How I can set the temperature and change rate?
Well, since hydraulic oil is practically incompressible, any work done to compress it results in the oil heating up - its internal energy increases, if its kinetic energy (flow) remains constant.

You essentially have three kinds of places, where internal energy can increase:

  • Hydraulic pump / circulation pump
  • Heaters
  • Pistons and valves
And of course, just the WSB to decrease internal energy again to prevent damage to the hydraulic components: excessive temperature damages seals and valves.



Also, heat conduction through the shuttle structure can increase temperature, but since we have no thermal model right now, assuming this balance to be zero would be OK.
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Old 12-11-2018, 11:16 AM   #2133
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Quote:
Originally Posted by Urwumpe View Post
 Well, since hydraulic oil is practically incompressible, any work done to compress it results in the oil heating up - its internal energy increases, if its kinetic energy (flow) remains constant.

You essentially have three kinds of places, where internal energy can increase:

  • Hydraulic pump / circulation pump
  • Heaters
  • Pistons and valves
And of course, just the WSB to decrease internal energy again to prevent damage to the hydraulic components: excessive temperature damages seals and valves.



Also, heat conduction through the shuttle structure can increase temperature, but since we have no thermal model right now, assuming this balance to be zero would be OK.
IMO, leaving just the pumps as "heat sources" (and the WSBs as "heat sinks") would be fine for now.
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Old 12-11-2018, 11:57 AM   #2134
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Originally Posted by GLS View Post
 IMO, leaving just the pumps as "heat sources" (and the WSBs as "heat sinks") would be fine for now.
Yes. The aerodynamic forces on the control surfaces are second strongest heat source.
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Old 12-11-2018, 02:17 PM   #2135
Abdullah Radwan
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I want to program a realistic elevon actuator. The current one is super simple.

To make it more realistic, I need to have some information:

First: I don't understand how to make an elevator while I have 2 actuators. Each actuator controls one aileron, how to make the elevator?

Second: I want to know every system uses the elevon, and how it's used. I want to have a general picture about aerosurfaces system. Also, an explanation why elevon isn't separated:
Code:
	//DiscInPort LeftElevonCommand, RightElevonCommand;
	DiscInPort ElevonCommand, AileronCommand, RudderCommand;
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Old 12-11-2018, 02:30 PM   #2136
Urwumpe
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Quote:
Originally Posted by Abdullah Radwan View Post
 First: I don't understand how to make an elevator while I have 2 actuators. Each actuator controls one aileron, how to make the elevator?
Actually, its elevons and ailerons on each wing. Not classic elevators and only the out-most control surfaces on the delta wing are plain ailerons.
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Old 12-11-2018, 02:32 PM   #2137
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Quote:
Originally Posted by Abdullah Radwan View Post
 I want to program a realistic elevon actuator. The current one is super simple.

To make it more realistic, I need to have some information:

First: I don't understand how to make an elevator while I have 2 actuators. Each actuator controls one aileron, how to make the elevator?

Second: I want to know every system uses the elevon, and how it's used. I want to have a general picture about aerosurfaces system. Also, an explanation why elevon isn't separated:
Code:
    //DiscInPort LeftElevonCommand, RightElevonCommand;
    DiscInPort ElevonCommand, AileronCommand, RudderCommand;
The term "elevon" is a combination of two separate terms, "elevator" and "aileron". Elevons act as both elevators and ailerons using only a single control surface on each wing. This saves weight as you don't have to have a separate wing (the 747 is an excellent example as the elevators are on the aft horizontal stabilizer while the ailerons are on the main wings) for each.
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Old 12-11-2018, 02:37 PM   #2138
Abdullah Radwan
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Quote:
Originally Posted by Urwumpe View Post
 Actually, its elevons and ailerons on each wing. Not classic elevators and only the out-most control surfaces on the delta wing are plain ailerons.
How this is currently implemented in Orbiter?

Also, why disable and enable control surfaces functions don't use SetADCtrlMode instead of creating and removing the surface?
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Old 12-11-2018, 02:46 PM   #2139
Urwumpe
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Quote:
Originally Posted by Abdullah Radwan View Post
 Second: I want to know every system uses the elevon, and how it's used. I want to have a general picture about aerosurfaces system. Also, an explanation why elevon isn't separated:
Code:
    //DiscInPort LeftElevonCommand, RightElevonCommand;
    DiscInPort ElevonCommand, AileronCommand, RudderCommand;
On the second question: Don't read the current state in the code too much. Its outdated and rudimentary. Follow SCOM and technical drawings.

And for example, these manuals:

https://www.nasa.gov/centers/johnson..._wsb_21002.pdf

https://www.nasa.gov/centers/johnson...book_21002.pdf
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Old 12-11-2018, 02:46 PM   #2140
GLS
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Quote:
Originally Posted by Abdullah Radwan View Post
 I want to program a realistic elevon actuator. The current one is super simple.

To make it more realistic, I need to have some information:

First: I don't understand how to make an elevator while I have 2 actuators. Each actuator controls one aileron, how to make the elevator?

Second: I want to know every system uses the elevon, and how it's used. I want to have a general picture about aerosurfaces system. Also, an explanation why elevon isn't separated:
Code:
	//DiscInPort LeftElevonCommand, RightElevonCommand;
	DiscInPort ElevonCommand, AileronCommand, RudderCommand;
You don't care what the actuator is going to do: SSME valve, LIB actuator, brakes, etc. They all have many things in common, especially now that this work is just starting. Some will have 1 hydraulic system, others will have 2 (and some 3?), and there will also be some differences in the way they are commanded, but let's leave that for later.
IMO, right now they should receive a command between 0 and 1, and output a value between 0 and 1, where 0 is fully retracted and 1 fully extended. The trick here is getting the motion rate correct for a certain hydraulic pressure and flow rate.
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Old 12-11-2018, 02:48 PM   #2141
Urwumpe
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Quote:
Originally Posted by Abdullah Radwan View Post
 How this is currently implemented in Orbiter?

Also, why disable and enable control surfaces functions don't use SetADCtrlMode instead of creating and removing the surface?
Possibly because the aerodynamic model is much different to what you will find on standard orbiter vehicles.
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Old 12-11-2018, 02:53 PM   #2142
GLS
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Also, the aerosurfaces have been changed in the OrbitersimBeta branch, so don't play around much with them as they will change when I merge to the trunk. For now just create a test actuator and play with it for development.

---------- Post added at 02:53 PM ---------- Previous post was at 02:50 PM ----------

Quote:
Originally Posted by Abdullah Radwan View Post
 How this is currently implemented in Orbiter?

Also, why disable and enable control surfaces functions don't use SetADCtrlMode instead of creating and removing the surface?
We only have 1 "regular" aerosurface which is the rudder. For all the others we have tables that give us lift, drag and forces that we set.
IMO, the enable/disable functions shouldn't really exist (both for aero and for RCS). The things are always there, if we use them or not is up to the GPCs.
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