Ordeal initialization Apollo 8mcc

[Sloppyphan]

Having trouble understanding what exactly I am supposed to do for the yellow c/l commands Att set (3) to fdai and the att null? Is it the p,r,y wheels to match ball as best as possible? Please help.. first q I'm sure not the last....

 

[indy91]

This is not part of the ORDEAL Initialization itself, do you mean the SCS Attitude Ref Comp Check? Or GDC Alignment To IMU?

In any case, if it is the line "ATT SET tw (3) - null FDAI 1 att err" that is giving you trouble, that means you should adjust the PYR wheels until the error needles on FDAI 1 are all centered.

 

[Sloppyphan]

GDC Align & Ordeal

Opps Rookie mistake there, that was about the GDC Align, I see how that works now, my next question was actually about on Ordeal

I got the avg Alt part adjusting the slide wheel accordingly, but for the pitch slew my R3 was 00053 which I took as 5.3deg but it also seemed to continue to be slowing climbing up.. Am I just pitching up the FDAI ball by approx 5 deg or am I rotating the ball all the way till it's at approx 5 degs from where ever it is .. I am thinking this is a get it close process as getting it exact would seem to be a bit of a best guess . .?
Thanks for the help! This is a amazing mod!

 

[indy91]

00053 is actually 0.53° not 5.3°. As a reference for verb and nouns codes and their displayed units see the G&C Checklist under Doc\Project Apollo - NASSP\Word Checklists. Or if you want to look at the flown Apollo 8 checklists see here: https://www.ibiblio.org/apollo/links.html#Checklists The CMP Checklist would also have this information.

Anyway, the purpose of the ORDEAL is to show you a local horizon reference instead of the inertial reference the FDAIs usually show. So if the ORDEAL is active (switch in orb rate) it will continually rotate the FDAI in pitch, after you gave it the initial pitch angle. The 0.53° is your current angle above the horizontal. Not a surprise if you are in Earth orbit, that's what the S-IVB is trying to keep as the attitude, pointing directly at the local horizontal. So what you want to do in this procedure is to rotate the FDAI until it shows 0.53°. You won't get this exact, but a few degrees off isn't so bad. It's just a visual reference for the astronauts anyway. You pretty much can just rotate it to 0° on the FDAI, that's easier as there is a line on the FDAI for that.

 

[Sloppyphan]

GDC Align and Ordeal

Yah, right after I posted, realized had the decimal wrong when looking at the checklist again. I need to have a screen shot or reference up when typing the question. Thank you for the explanation, I was wondering how much of it was critical vs astronaut comfort/familiarity.