Problem AMSO and Orbiter build 110824

[alagreca]

Whilst using AMSO 1.2 with Orbiter build 110824 the autopilot always stops at exactly 6:40 GET. It is still possible to reach a good parking orbit with a little practice as the AMSO Saturn V is quite stable with good response to manual controls. This does not seem to be related at all to the former LOI crossrange issue as the crossrange is always well past it's peak and in decline when the autopilot stops. I have also noticed that Multistage 2 rockets with guidance files end up with lower than normal apogees and sub orbital perigees. With AMSO the rocket would normally be close to it's 187 KM parking orbit altitude by GET: 6:40 when the autopilot stops. I am now seeing numbers in the 170's at this point. AMSO'S autopilot is most likely stopping because it can't gain it's proper altitude for some reason in a similar way to how it was stopping because it could not lower the LOI crossrange in that case. I just cant figure out why. At first I thought it might be the new atmosphere model but switching to the static model produces the same results. The other main suspect that comes to mind is that orbiter may have changed the way it calculates the ISP for a rocket engine when converting fuel consumption to DV. Does anyone have any ideas.

 

[jarmonik]

Have you tried to disable atmospheric wind effects from parameters tab ?

 

[alagreca]

No. I just changed the global atmosphere to the legacy 2006 model. I will try your suggestion. By the way, thank you so much for all of your wonderful contributions to Orbiter. Most especally the D3D9 client and LTMFD. LTMFD had given AMSO the full maturity to fly a complete apollo mission in the way LazyD would have wanted if he had not left this life before His time. Thanks

---------- Post added at 09:21 PM ---------- Previous post was at 12:29 PM ----------

O.K Same rusult. I ran across a post on another thread indicating the AMSO folks know about this and that it will be resolved in release 1.21. As far as other ships are concerned I am starting to think this is not a bug or problem at all, but rather an increase in the fidelity of the core Orbiter physics engine that will have to be adapted to. Kind of like the way the landmarks at KSC have been migrating around since '06 or so. By the way. I still have 1 installation of build 100606 for Shuttle Fleet use, due to the autoFCS problems with later builds, was there ever a D3D9 that worked with that build. I have them all archived back to the alphas. Cheers.

 

[FordPrefect]

alagreca,

I just tried AMSO 1.2 on Orbiter build 110824, D3D9client RC34b, Apollo 12 launch scenario. Autopilot worked flawlessly resulting in a nominal LEO insertion! Hmm...
Which scenario were you running?

 

[alagreca]

AS-506 step 1

I was using AS-506 Step 1. This problem is probably related to the wind effect option being turned on. The Autopilot works fine from AS-506 Step 2 even with wind effect turned on. It begins just before S1-C center engine cutoff, above most of the atmosphere. The developers are working it out. Please dis-reguard my idea about the way orbiter calculates DV. I was completely wrong.