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Old 10-21-2019, 04:58 PM   #46
BrianJ
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Hi,
Quote:
Originally Posted by francisdrake View Post
 The vessel seems more stable with the fins swept back. I see a change in the acceleration between extended / retracted which I assume is done by changing the wing area?


Unfortunately Orbiter seems to allow only horizontal and vertical wings, defined by LIFT_VERTICAL and LIFT_HORIZONTAL. I would add vertical fin(s) with the area of the main fins x sine of the sweep angle. If you keep their lift function low, there should be no crazy spinning.

Could the fins being used during reentry? Well, 'normal' lifting bodies like ESA's Space Rider use body flaps to trim the AoA during reentry. So I would assume a slight deviation from the swept-back orientation would be ok to assist the RCS.
By the way, I guess the swept-back angle is more than 45°, maybe like 70° for the initial reentry phase, to keep the forces on the fins low.
Yes, what I have so far is a vertical and a horizontal aerofoil for the Hull 450m^2 each, two Canard aerofoils 18m^2 each, two Wing aerofoils 54m^2 each. The Canard and Wings are scaled by cos(deflection) angle.
There is now also a "vertical" aerofoil for the wings,scaled by sin(deflection). This adds a bit more yaw/roll stability.

I moved the hull CoP up and back a tiny bit, which gives an AoA of ~58deg. And you can trim that up or down by setting a small deflection in the wings for extra or less drag.

Default fin deflection is 60deg in Reentry mode.
Aerofoil steering in Reentry mode now possible.




Quote:
Originally Posted by francisdrake View Post
 A note on future versions: The hinges on the current SpaceX Starship look makeshift. I doubt they will be the same on the final production versions. They might either be more blended-in into the body, or the body will get a sharp edge just below the hinges to force airflow separation.
Yes, the Mk.1 is obviously not designed to go much above 20km!
I'm just distracting myself thinking about doing reentries with it, I know :-)


Added throttle control to the Anti-groundspeed attitude function - so now it's a "Flip'n'Land" function - use from 4km to 2km alt. depending on vertical speed. No targeting though.

Also added BocaChica base (very simple) and a couple of scenarios including a recorded REPLAY of my best landing at BocaChica.

If you're doing any flights from Texas, I can recomend grabbing the Hi-Res Earth textures for the BocaChica area here:
https://mirror.orbiter-radio.co.uk/o...thHi_10_07.zip

Anyway, here's the latest beta .zip
starship_mk1_beta_191021.zip

Cheers,
Brian
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Old 10-23-2019, 07:37 PM   #47
francisdrake
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I took the Starship for a trip from LEO to lunar landing, using the 'Challenge 2 - Lunar transfer' scenario, replacing the Delta Glider with Starship.
It worked, after some trial and error. The picture above shows the ship incoming using the Flip'n'Land function.

Very nice trip! Started with full tanks from LEO and arrived with 12 ton fuel remaining on the lunar surface.

Two remarks:
Maybe the wing movement could be turned off completely for space operations (e.g. as an additional 'B' aerofoil mode).

I had occasional Orbiter crashes using the Killrot command in deep space. Maybe this was related to the wings flapping out of bounds, or their control algorithm exceeding a value, dividing by zero, or so.
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Old 10-23-2019, 10:41 PM   #48
BrianJ
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Nice! So much for "not designed for going above 20km"
You can turn off the aerfoil steering with ALT + NUMPAD /.
I'll have a look in the code for any possible CTD causes - could well be a math problem, away from Earth. Can't see why it would be related to KillRot function, but will check.

I learned from this talk that it's not a "Flip'n'Land", it's a "Reorientation Maneuver"
[ame="https://www.youtube.com/watch?v=x2gyo1hbheE"]SpaceX Principal Mars Development Engineer talks at Mars Society Convention 2019 - YouTube[/ame]

Cheers,
Brian
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Old 11-04-2019, 07:45 PM   #49
francisdrake
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Played around to dock the Starship to a tanker. Added a docking port to the rear of the Starship through the cfg-file.

Looking backwards while docking is possible by changing the view with 'E'. The backward/forward translational RCS is a little sluggish, as the thrusters mainly blow outward, only little in axial direction.
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Old 11-04-2019, 09:05 PM   #50
Jeremyxxx
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When is the rocket for the Starship (BFR) going to be made? because I have been wanting to see an unmanned variant for cargo scenarios.
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Old 11-05-2019, 03:35 PM   #51
BrianJ
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Quote:
Originally Posted by francisdrake View Post
 Played around to dock the Starship to a tanker. Added a docking port to the rear of the Starship through the cfg-file.

Looking backwards while docking is possible by changing the view with 'E'. The backward/forward translational RCS is a little sluggish, as the thrusters mainly blow outward, only little in axial direction.
Cool! In future, I might add a tanker+fuel-transfer variant.
My Mk.1 RCS is definitely not designed for orbital operations
But I hope we'll get some clear pics of what SpaceX are actually doing with the RCS, soon.


Quote:
Originally Posted by Jeremyxxx View Post
 When is the rocket for the Starship (BFR) going to be made? because I have been wanting to see an unmanned variant for cargo scenarios.
At the moment, I'm still having fun trying to figure out some kind of landing guidance for the Starship (I hope SpaceX are doing better than I), so might be quite a while before I get to doing boosters.


Cheers,
Brian
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Old 04-30-2020, 02:48 PM   #52
BrianJ
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Just a shout out to ask if anyone has any recent info or photos of the latest Starship build (SN.4?) regarding RCS placement (if any!) and aft blisters (will there be any, now the landing gear folds up inside?). I'm not finding much via google. Educated guesses welcome :-)

Finally made some progress with landing guidance algorithm (flies like a whale, steers like a whale). It's happy without Orbiter's "Atmospheric Wind Effects"*, but can just about cope with it on.

*I do wonder if Orbiter's surface winds are a bit extreme - some time ago, I tried calculating the "Wind shear" values up to 10km alt. and they seemed quite high, but I'm no pilot, and not sure if I was calculating correctly. It's just that you get hammered by a 50mph SW wind at ~3km alt., and then it swings round to 50mph N at ~1.5km alt. Any vessel with low lateral speed gets blown about somewhat!

Anyway, I think I can start making a launch pad for Boca Chica finally :-)
Cheers,
Brian
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Old 04-30-2020, 03:21 PM   #53
DaveS
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AFAIK, SN-4 is just the main propellant tanks plus the thrust section equipped with a single Raptor engine. Only static fires and a single 150 m hop (very similar to what the Star-Hopper did last year) planned for it. No nose cone, fins or thrusters. This is thread on NASASpaceflight.com that you should keep an eye on as far as Starship development is concerned: https://forum.nasaspaceflight.com/in...pic=48895.2540
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Old 04-30-2020, 03:28 PM   #54
4throck
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Just to add that SN5 will have 3 engines and probably a more complete attitude control system. That's the one to look out for.
SN4 is mostly an engine/tank tester.
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Old 04-30-2020, 04:50 PM   #55
BrianJ
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Thanks for the pointers, guys :-) NASA forum page bookmarked.
So, I guess I'm chasing the SN5, with an eye on the "20km hop" test (if that's still in the plan). Interestingly, I find I only need RCS to finesse the landing final approach from 6km alt., and only if Orbiter's wind is active. If SpaceX have better aerodynamic control and wind compensation strategy, they might not need RCS at all, for the 20km hop.
Cheers,
Brian
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Old 04-30-2020, 05:00 PM   #56
DaveS
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Quote:
Originally Posted by BrianJ View Post
 Thanks for the pointers, guys :-) NASA forum page bookmarked.
So, I guess I'm chasing the SN5, with an eye on the "20km hop" test (if that's still in the plan). Interestingly, I find I only need RCS to finesse the landing final approach from 6km alt., and only if Orbiter's wind is active. If SpaceX have better aerodynamic control and wind compensation strategy, they might not need RCS at all, for the 20km hop.
Cheers,
Brian
Plans seem to change daily, so what is currently the plans for SN-5 could change tomorrow. It seems to be linked to the fact that despite outward appearances, they still don't have the manufacturing down. This is further evidenced by the fact that they barely got SN-4 through its cryogenic pressure test. They were aiming for 123 PSI (8.5 bar) but called it done at 71 PSI (4.9 bar).
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Old 04-30-2020, 05:37 PM   #57
BrianJ
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Thanks. Yes, not easy to keep up with SpaceX plans ;-)
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Old 05-05-2020, 11:34 PM   #58
BrianJ
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3D modelling fun with many girders......
screenie1.jpg
I guess they probably won't use that stand for anything other than test firing, but it'll do for me for now.

Another day at (virtual) Boca Chica....
screenie2.jpg

@Donamy
It was nice of BlueOrigin to lend SpaceX their Z6034 cherry-picker ;-)
I updated it so it works in Orbiter2016, although it tends to slide on slopes.
Zip file attached for you, at the bottom of this post.
Cheers,
Brian

z6034_200505.zip
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