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Re: Space Shuttle

Postby Thorsten » Sat Jul 09, 2016 7:26 pm

Big moment... the AP just brought the first Shuttle home after an engine failure 30 seconds into the flight via an RTLS abort - from liftoff right to the turn into final.

The flight history shows the elongated flightpath reaching some 355 miles out before turning back, then an S-turn during TAEM to dissipate energy, followed by the HAC.

Image

It's quite a ride to sit through this...
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Re: Space Shuttle

Postby wlbragg » Sat Jul 09, 2016 7:41 pm

Now that is cool! I'll have to give it a go and see if I can survive.
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Re: Space Shuttle

Postby wlbragg » Mon Jul 11, 2016 5:44 am

@Thorsten, the APU Start/Stop switch is a 3-way switch, Ready/Start, Off, Injector Cool. I modeled it as a 3-way with Injector Cool being the same as "Off" (ie: if switch > 0 Ready/Start = true). I think the switch outputs 1, 0, -1, where -1 would be Cool Injector. Is there any logic for Injector Cool?
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Re: Space Shuttle

Postby Thorsten » Mon Jul 11, 2016 5:54 am

No, we don't have injector cooling modeled yet - but it's good to have the state in the switch, then we can always map it to the real thing if needed.
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Re: Space Shuttle

Postby Thorsten » Wed Jul 13, 2016 6:18 pm

Read through the 'Contingency Aborts' workbook today - interesting stuff. I guess I'll implement some of the relevant guidance as well, I have single engine roll control already, and the rest is basically RTLS with different targets.

Might be interesting to aim for Bermuda after a two engine out early on...
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Re: Space Shuttle

Postby legoboyvdlp » Wed Jul 13, 2016 6:38 pm

Thorsten wrote in Sat Jul 09, 2016 7:26 pm:The flight history shows the elongated flightpath reaching some 355 miles out before turning back, then an S-turn during TAEM to dissipate energy, followed by the HAC.

Image



Might be a 270 degree turn -- an s turn looks exactly like an S, as I'm sure you know!

On the other hand, you did turn left then right (after a while), so it might qualify as an S-turn! Or maybe I just didn't look close enough :D
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Re: Space Shuttle

Postby wlbragg » Thu Jul 14, 2016 2:55 am

Playing with the abort system.

Houston, we got a problem!
Image

Solids away, land ahoy.
Image

Please let me get back in one piece, ET away.
Image

Well, as long as the copters get to me on time, I survived, but I still got some training to do.
Image

This sure is a fun ship to play with!
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Re: Space Shuttle

Postby Thorsten » Thu Jul 14, 2016 5:52 am

Might be a 270 degree turn -- an s turn looks exactly like an S, as I'm sure you know!


Please look into the Shuttle TAEM terminology - all phases are actually described nicely.

The 270 degree turn is the spiral down the HAC (heading alignment cone), the S-turn is the change in approach path before. If there would not be an S-turn, there'd be a single curve towards the HAC tangent from 80 miles out, as it is, Delta Azimuth to the tangent point first increases, then decreases, then increases to the opposite site before the trajectory aims directly at the tangent, and that's called an S-turn (regardless of whether you see that in the projection later or not).
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Re: Space Shuttle

Postby wlbragg » Thu Jul 14, 2016 8:05 pm

While doing the talkbacks on the landing gear deploy for ease at the time I opted for 3 objects (up, barberpole,down) and used a select. I am pretty sure I should have used a textranslate instead. Main reason being I am seeing some weird z-fighting behavior when looking at the talkback from an extreme angle (like looking at the pilot talkback while sitting in the command seat).

Why would you ever see the non-selected object?

EDIT:
Well I answered my own question.
You will see this when you have the logic wrong and have both objects selected at the same time.

Problem solved, although I probably should still have used the textranslate.
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Re: Space Shuttle

Postby Thorsten » Mon Jul 18, 2016 6:11 pm

Teaching the Shuttle G&C to fly contingency aborts... The avionics can now note the failure inertial speed of engines and determine the contingency procedure to be executed (here's a two engine failure in the BLUE region as an example).

Image

The AP knows how to do the procedure for BLUE and GREEN in powered flight (the others are to come) and can compute dynamically optimum Nz after handing over to unpowered flight). My current vision is to be able to do an East Coast / Bermuda abort eventually. And perhaps to support bail-out by using the parachutist piggy-backed on the Shuttle sim :-)

Single engine flight dynamics is bitchy in more than one way. First, the fact that the trajectory predictors inevitably drop like a rock is slightly depressing. Second, it's really crucial to get the roll channel off the engines - I spent two hours figuring out why I had no pitch authority before I figured out that the DAP was still trying to utilize a thrust vectoring roll.

Even single engine roll control (SERC) isn't without pitfalls, because it needs to be active right when the OMS fuel dump happens - the solution is to do mirror-imaging, rather than, say, firing the left pod up thrusters, one inhibits left pod down thrusters for a moment (and vice versa).

It's very subtle (the upward flame is missing on the left) but this is rolling the Shuttle under SERC with a fuel dump going on:

Image

I absolutely love implementing all these little details about the Shuttle. It's ingenious how it all works together.
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Re: Space Shuttle

Postby wlbragg » Mon Jul 18, 2016 11:20 pm

How can I get the CW lights to look good or bright under daylight conditions? As you can see it looks OK in the dark but not in full light. Same for the engine status lights.

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Re: Space Shuttle

Postby Thorsten » Tue Jul 19, 2016 4:49 am

Wildly guessing - the fact that they seem to lose color value in sunlight indicates that their ambient and diffuse colors are set to white/grey, so it's only the emissive channel which carries color - that dominates at nigh but not during the day.
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Re: Space Shuttle

Postby amalahama » Tue Jul 19, 2016 8:49 am

Thorsten wrote in Mon Jul 18, 2016 6:11 pm:I absolutely love implementing all these little details about the Shuttle. It's ingenious how it all works together.


And we love flying them! :D I really hope you don't get tired of the Space Shuttle any time soon :) You and also wlbragg are doing an awesome work, I can't wait to see what the future is bringing :)

I need to catch up with flying the shuttle though, I've been through some busy months with no time for amusement. But with the current maturity level is quite hard to fly the shuttle without proper documentation. I kind of manage normal ops because of my previous experience with other STS simulators but contingency aborts, that's another story! If you need a programming break, it would be nice that you record some videos practicing aborts, so we can have a better picture of the whole procedure.

Regards!
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Re: Space Shuttle

Postby wlbragg » Tue Jul 19, 2016 2:47 pm

Thorsten wrote in Tue Jul 19, 2016 4:49 am:Wildly guessing - the fact that they seem to lose color value in sunlight indicates that their ambient and diffuse colors are set to white/grey, so it's only the emissive channel which carries color - that dominates at nigh but not during the day.

Good guess, that was the problem.

Assigning materials in Blender is still a bit of a mystery to me, but I think I figured out how to create and assign a new material without messing up the rest of the objects and I am able to get the yellow and red in the bright sun light.
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Re: Space Shuttle

Postby Thorsten » Tue Jul 19, 2016 5:04 pm

Theoretically you ought to be able to use a material animation - though editing the material is probably easier.
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