G42-200

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Author: Moach

Discussion thread: http://www.orbiter-forum.com/showthread.php?t=21197

Download page: http://www.orbithangar.com/searchid.php?ID=5456

Basics[edit]

The G42 is a near-future SSTO designed for operation from normal airports. Equipped with four different "main" engines, the Starliner is a challenging aircraft to get off the ground. As such, there is a checklist that goes along with the startup, launch, ascent, and orbital insertion phases of flight.

This is the checklist as it stands today:

Flight and systems model: WIP-303

1 - engines start

  • master feed pumps - all three on
  • apu feed pump - on
  • apu - start
  • engine mode - check EXT shown on EICAS
  • burner/reheat - off
  • turbine cycle - start

2 - takeoff

  • canards - extended - cycle once (tap 'N' twice to clear off scenario load bug)
  • visor - down
  • wings - center
  • burner/reheat - on
  • flight controls - check
  • seatbelts - fasten!
  • throttle - crank up to 80%, allow engines rev-up - floor it!
  • rotate - pitch up slowly to 10 degrees max (lest tailstrike)
  • positive rate - confirm, and increase pitch for climbout
  • gears - UP


3 - climbout

  • burner/reheat - off
  • airspeed - hold subsonic
  • altitude - climb to FL350 (~10km)
  • ATC - imagine yourself getting the needed clearances now

4 - supersonic transition

  • airspeed - above mach .85
  • altitude - approaching 10km
  • canards - retract
  • visor - extend
  • burner/reheat - on (past mach 1.5 as required)
  • throttle - 80~100%

5 - T1 (ramcaster insertion)

  • flight envelope - check eicas graph converging on T1
  • ramcaster doors - open
  • ramcaster throttle - to 60% (where it says 'ENG')
  • burner/reheat - off
  • ramcaster - ignition, confirm (audible "boom" and MODE:LO shown on eicas)
  • acceleration - check increased forward rate
  • main eng throttle - close
  • ramcaster throttle - full
  • turbine cycle - cut
  • main engines mode - INT
  • wing position - to HPC after mach 3.5

6 - T2 (ramcaster mode transition)

  • flght envelope - check converging on T2
  • ramcaster mode - transition to high
  • confirm transition - audible rumble sound, eicas shows MODE:HI
  • flight envelope - proceed to T3
  • MFDs - Orbit display, as required

7 - T3 (rocket mode transition)

  • flght envelope - check converging on T3
  • main fuel supply - ~80k
  • oxidizer feed pumps - both on
  • stby ignition - RCS on
  • rcs feed pump - on
  • main throttle - 25%
  • engine mode - check INT on eicas
  • turbine cycle - start
  • gen pct (rpm) - rising
  • rocket start - confirm - check tape gauge shown on eicas
  • ramcaster throttle - close
  • ramcaster cycle - cut
  • ramcaster doors - close
  • main throttle - full
  • RCS mode - rotation
  • orbit progress - monitor

8 - orbit insertion

  • HUD - orbit
  • ApA (Apoapsis) - converging on target as planned
  • throttle - keep accel under 1.5G's as requred by mission/crew profile
  • ApA mark reached - check
  • throttle - close (engines will shutdown when in rocket mode)
  • turbine cycle - cut
  • master feed pumps - all off
  • oxidizer feed pumps - both off
  • ApA/ApT - check and monitor
  • atm pressure - check surface MFD showing N/A and zero dns
  • visor - down (lo and behold - you're in space!)
  • RCS doors - open

9 - circularize

  • ApT - minimum T-100s before mark
  • stby ignition - OMS on
  • oms feed pump - on
  • thr authority - OMS
  • oms capability - check 'OMS' shown on HUD
  • ApT - hold for mark as required
  • throttle - open as required
  • ApA/PeA (Periapsis)//Ecc - monitor until OMS cutoff

10 -

  • bay doors - open (press 'B', switch not installed yet)
  • awesome - you are now!
  • drinks - on the house! (depending on program budget)


Operational Use[edit]

The Starliner does have a payload bay behind the cockpit. This is large enough to accomodate a Delta II upper stage, with payload, and still have room to spare. However, there is no payload management system at this time. There are two attachment points on the G42, and both of them can be used to fit payloads in the bay. Caution MUST be used when using Universal Cargo Deck, as there have been several issues surrounding the use of UCD with the G42, such as uncontrolled movements and tremors while on the ground.

With a little practice, the G42-200 can be used as the first stage of a launch system with a disposable second or even third stage being used to perform the orbital insertion. A good candidate is the Velcro Delta II second stage, with either a Star 37 or Star 48 solid rocket motor being used as the optional third stage, like the Delta II. Experimentation is encoraged, however, and there will likely be other stages that can fit inside the bay.

Flying with a full load of oxidizer can lead to a failure top reach orbit.

There are several interesting features to the G42. One of them is the ability to "skip" long distances across the atmosphere when lightly loaded, such as after a failed orbital insertion. By leaving the wings in High Performance Cruise setting, you can traverse half the planet at speeds in excess of 5 km/s.

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