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Glycol Loop Check problem
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Topic: Glycol Loop Check problem (Read 1188 times)
Dogsbody
Full Member
Posts: 35
Glycol Loop Check problem
«
on:
October 29, 2011, 06:39:27 AM »
Hi.
I have been fiddling around with NASSP a bit, gotten into orbit and done TLI but I find myself wanting to go a bit deeper and understand more of what I am doing. So, I started Apollo 7 with that aim and didn't get very far before encountering my first issue.
Firstly, can someone explain the EMS tests to me in layman's terms, especially where to slew the scroll to for test 2 and test 5. I don't understand the terminology I think.
Then I moved on to the Glycol loop checks (pg L1-3 on Word checklists). I set GLY TO RAD SEC to NORM and all the indicators are correct according to what tyhe checklist says...except for RAD SEC OUT TEMP and SEC GLY EVAP OUT TEMP. Those two start dropping to the bottom of the gauge the moment the GLY TO RAD SEC valve is set to NORM. What did I do wrong?
Also, the AOH Volume one keeps talking about the ECS being at 40 something degrees fahrenheit, not 60 to 95. Is that during the flight, not on launchpad?
One last question. What does pegged mean? What about those values is pegged?
I apologise if these questions have already been covered in another thread but I couldn't find an answer, even after searching the threads.
Thanks in advance
Doug Dougsbody
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almostfm
Full Member
Posts: 39
Re: Glycol Loop Check problem
«
Reply #1 on:
October 29, 2011, 01:05:25 PM »
I think I can answer the easy part
Mechanical gauges often have a "peg" to stop the needle from moving past the highest reading on the scale. When a gauge is "pegged", it means that whatever the gauge is measuring is higher than the maximum value the gauge can show.
Suppose you've got a temperature gauge that reads up to 100 degrees. Any temperature reading above 100 would peg the gauge.
Scott
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Dogsbody
Full Member
Posts: 35
Re: Glycol Loop Check problem
«
Reply #2 on:
October 29, 2011, 09:57:18 PM »
Thanks. That makes sense, since the gauge only goes to 70 and the range goes up to 97. Was wondering about that.
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meik84
Project Team Member
Sr. Member
Posts: 299
Re: Glycol Loop Check problem
«
Reply #3 on:
October 30, 2011, 09:41:36 AM »
Quote
Firstly, can someone explain the EMS tests to me in layman's terms, especially where to slew the scroll to for test 2 and test 5. I don't understand the terminology I think.
Place the 'bug' between the leftmost vertical and the diagonal line. The rest should come by itself, I hope.
Quote
Then I moved on to the Glycol loop checks (pg L1-3 on Word checklists). I set GLY TO RAD SEC to NORM and all the indicators are correct according to what tyhe checklist says...except for RAD SEC OUT TEMP and SEC GLY EVAP OUT TEMP. Those two start dropping to the bottom of the gauge the moment the GLY TO RAD SEC valve is set to NORM. What did I do wrong?
Nothing. AFAIK we don't simulate the ambient air temperature on the radiator's surfaces, so they work in the warm florida air like they would work in cold space. In reality, it was of course impossible to cool the glycol below the ambient air temp and the checklist considers this fact.
Quote
Also, the AOH Volume one keeps talking about the ECS being at 40 something degrees fahrenheit, not 60 to 95. Is that during the flight, not on launchpad?
Which temp? 40°F is pretty normal for EVAP OUT, 60 - 95 ° F is pretty normal for RAD IN.
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Dogsbody
Full Member
Posts: 35
Re: Glycol Loop Check problem
«
Reply #4 on:
October 31, 2011, 12:02:46 AM »
Thanks Meik. Still can't figure out why the checklist says the gauge should read between 60 and 95 for the RAD SEC OUT but instead it drops the moment I put the bypass to norm.
Hopefully someone can help me understand. Want to make sure I get these basics right before moving on.
Thanks for the help with the EMS. Now all I need to understand is what they mean on page L 1-3 when they say: stylus is at 0.28g. What tells me where 0.28g is? and what does 1 step of ground test pattern mean? And which delta V instructions are they talking about?
I guess I have a lot more reading to do before I can fly with understanding rather than just following the checklist.
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eddievhfan1984
Full Member
Posts: 231
Re: Glycol Loop Check problem
«
Reply #5 on:
October 31, 2011, 03:07:26 AM »
If doing your EMS check on the ground, make sure your GTA switch is turned on, to compensate for gravity.
Step 1: Set EMS MODE to TEST 1, and scroll the EMS marker to the notch in the test pattern, between the vertical and diagonal lines.
Step 2: " TEST 2, and after 10 seconds, the .05G indicator should line up.
Step 3: " TEST 3, and the .05G indicator will light up immediately. After 10 seconds, the bottom (down) light in the lift indicator (the circular display with the triangle in the center) should light up. Then slew the dV/RANGE indicator to 58.0.
Step 4: Set EMS MODE to TEST 4, and the marker will trace a diagonal line for 10 seconds, with the .05G light on. The dV/RANGE indicator will also count down. After the trace has stopped in that narrow vertical notch at the end of the pattern, check that dV/RANGE is 0.0±0.2.
Step 5: Set EMS MODE to TEST 5, and the .05G light will come on. After 10 seconds, the top light in the lift indicator will light, and the marker will trace to the top of the notch in the pattern, which is .28G, but NOT the very top of the EMS screen.
Step 6: Set EMS MODE to STBY, and the marker should pop up to the top of the screen, as well as zeroing out the dV/RANGE display.
Hope this helps.
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meik84
Project Team Member
Sr. Member
Posts: 299
Re: Glycol Loop Check problem
«
Reply #6 on:
October 31, 2011, 12:18:41 PM »
Quote
Still can't figure out why the checklist says the gauge should read between 60 and 95 for the RAD SEC OUT but instead it drops the moment I put the bypass to norm.
As I said: the checklist assumes that the radiators are in contact with earth atmosphere, which should have a temperature of 60 to 95° F (or 16 to 35 ° C -remember, we're in Florida
). It is impossible for the radiators to cool the glycol below this temperature (that's one of the basic principles of thermodynamics), so the glycol leaving the radiators should be around that temp.
In orbiter, we don't take this in consideration. The only things interfering the radiators are the sun's radiation and earth' or moon's albedo (the latter being simulated rather bad), so that even on the pad the glycol can be cooled to 40° F or less.
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eddievhfan1984
Full Member
Posts: 231
Re: Glycol Loop Check problem
«
Reply #7 on:
November 01, 2011, 01:48:28 AM »
Also, isn't the surface temp of Earth in Orbiter very low, like close to freezing?
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Dogsbody
Full Member
Posts: 35
Re: Glycol Loop Check problem
«
Reply #8 on:
November 01, 2011, 02:26:10 AM »
Thanks for the replies. I have a much better understanding of the EMS now. Thank you.
As I understand the glycol issue, I don't need to worry if the gauge reading is too low on the pad because Orbiter doesn't model the temperature at the pad? Will read up some more about this but I think I get it. Thanks for your help.
Now to move ahead with the checklist.
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meik84
Project Team Member
Sr. Member
Posts: 299
Re: Glycol Loop Check problem
«
Reply #9 on:
November 02, 2011, 06:48:28 AM »
Quote
Also, isn't the surface temp of Earth in Orbiter very low, like close to freezing?
Surface MFD shows an OAT of 288 K, which is a little less then 15 °C -quite normal for a Florida winter morning, I guess...
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Dogsbody
Full Member
Posts: 35
Re: Glycol Loop Check problem
«
Reply #10 on:
November 02, 2011, 10:10:55 AM »
I don't suppose there's any way to tell NASSP that the outside temperature is different? Changing the earth surface temperature, the space temp and the moon surface temp will probably be important for the radiator readings throughout the mission and for other reading ete, not just to make the radiator reading match the checklist?
Or is that a major programming challenge. I find myself wishing I had learned programming just for NASSP so I could help.
PS: On that note and on a totally different topic...If I downloaded Blender how difficult would it be to learn how to convert the 2d panels for the 3D cockpit. If someone can teach me just enough of using Blender that I can do that, I might be able to spend the time needed to map each button's co-ordinates. (I have to sit up in the wee hours feeding my son through a tummy tube. Long story but let's just say doctors and aneasthetic now scare me immensely in case things go wrong.)and help us move closer to the 3D cockpit.
I don't know if it's something someone could teach me quickly though. If I have to learn how the whole of Blender works, that might take longer than it would take for one of you guys to do it around all the other good work you are doing on NASSP.
Thanks again for the best Apollo sim out there.
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meik84
Project Team Member
Sr. Member
Posts: 299
Re: Glycol Loop Check problem
«
Reply #11 on:
November 02, 2011, 01:15:53 PM »
Quote
I don't suppose there's any way to tell NASSP that the outside temperature is different?
The simulation of the radiators seems rather simple to me. It's just not implemented, that's it.
Quote
Changing the earth surface temperature, the space temp and the moon surface temp will probably be important for the radiator readings throughout the mission and for other reading ete, not just to make the radiator reading match the checklist?
Indeed. Especially in lunar orbit, our simulation is far from reality: there's nearly no difference in the glycol temp between the day side of the moon or the night side. In reality, moon's albedo in the infrared spectrum is so high that the radiators were nearly ineffective for removing the heat and the evaporator had to take over on the day side. AFAIK this led to the strange effect that it was better to point the radiators toward the sun then toward moon's surface.
Quote
Or is that a major programming challenge.
I guess this is rather a challenge of thermodynamics. I understand the basic principles, as they are thought in school -but a fully understanding of the behavior of a radiator in different environments is far from my understanding.
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Tschachim
Project Apollo - NASSP
Administrator
Hero Member
Posts: 3687
nassp.sf.net
Re: Glycol Loop Check problem
«
Reply #12 on:
January 14, 2012, 05:58:39 PM »
Quote from: Dogsbody on October 29, 2011, 06:39:27 AM
Then I moved on to the Glycol loop checks (pg L1-3 on Word checklists). I set GLY TO RAD SEC to NORM and all the indicators are correct according to what tyhe checklist says...except for RAD SEC OUT TEMP and SEC GLY EVAP OUT TEMP. Those two start dropping to the bottom of the gauge the moment the GLY TO RAD SEC valve is set to NORM.
Fixed that, there was a bug in the glycol loop handing while on ground (i.e. connected to GSE).
The Moon's albedo problem is not fixed, it's not that easy and not relevant for Apollo 7, sorry.
Cheers
Tschachim
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Dogsbody
Full Member
Posts: 35
Re: Glycol Loop Check problem
«
Reply #13 on:
January 17, 2012, 02:17:25 AM »
Thanks Tschachim!
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