Flight Question Reentry Angle and Burn Location

[usmc3891]

I've done the tutorial on reentries and I can deorbit a DGIV on target with no problem. I'm having trouble with the XR-2 and XR-5. I always skip in the atmosphere and wind up about 1000km past my target. Can anyone give me the ideal angle and deorbit point for these vessels?

 

[Codz]

I'm not sure if this will help but here is one of Tex's films with the XR-2.

 

[agentgonzo]

Get AerobrakeMFD and use that. I normally enter at about 45° AoA with the XR2. If you're starting to increase in altitude and skip, then you need to pitch up.

 

[usmc3891]

I've been going with a 40 AOA. I'll try 45 and see what happens.

 

[Turbo]

That is what is so nice about the XR fleet. You can adjust your AOA anytime with the autopilot. I usually start at 40, and move to 45 - 50 at times, depending on my decent rate. Just keep adjusting to keep your rate anywhere between -80 to -100 m/s (depending on your preference for reentry) and you will not burn up, or skip off. I never use 1 AOA threw an entire reentry, I always adjust. From an ISS altitude, I try to decend at -90 m/s personally (burning at 18.3M from my target base)

 

[usmc3891]

I was able to deorbit right on target with both the XR-2 and the XR-5. Thank you very much for the help :tiphat: I can do a deadstick on the DGIV and the XR-2 but I'm going to need practice with the XR-5. I had to do powered flight for about 100km to get aligned with the runway at WideAwake, not counting the missed approach lol

 

[ADSWNJ]

I've been trying to get a good XR-5 deorbit burn with BaseSync. Angle 0.4 degrees, anticipation 45 degrees and reentry altitude of 80km, burn it (retrograde) when BaseSync says, then bring up surface HUD, roll level with the horizon, then pitch up to 40-45 degrees and let nature take its course. Then use AeroBrake to watch the vertical profile (set AoA to keep this profile smooth), and enjoy the ride down.

What really seems to be missing to me is a landing MFD that gives you a set of boxes to fly through similar to the docking MFD. In fact, if it could target you to a holding point abeam the airfield at say 60-70,000 feet and circle to land, that would be quite something. It's not like we are flying little Cessnas here - these are multi-billion dollar pieces of equipment, and they should have these facilities .

 

[blane]

You can use AerobrakeMFD for the initial aim so that you will come down near the base. Once you have the airfield in view, you can use the VOR/VTOL MFD to verify your glide path.

When doing a re-entry landing you will probably not use a standard ILS glide path anyway, unless you do a powered landing. Otherwise you will have a very steep descent and reduce your speed at the very last moment.

 

[Cras]

The method I use is a mix of Aerobrake MFD to help manage the energy, I use Basesync for a time to begin the deorbit burn, Aerobrake MFD to judge when to stop the deorbit burn, then Glideslope for the azimuth of the field, for the HAC and runway alignment. After flying the ShuttleFleet and XR-2 deadstick down to the runway so many times, I have developed a feel for where I need to be, and for what altitudes and ground speed to aim for during the arrival, HAC, and final approach.

That is the best advice really. Basesync, Aerobrake, Glideslope are some great MFDs and great tools for landing at a runway from orbit. Give them a look, and find a procedure that uses them and it will become a piece of cake.

And blane is right on with the glide path. For deadstick landings, the path will be much steeper than anything you will have seen done in an airplane. And once I hit about 800 meters, (in the XR-2), I lower the gear, pitch up the nose, and try to get the velocity vector right in the TDZ, for a nice landing back on Earth. Some adjustment may be required with that target altitude depending on the ship and the load you are carrying of course.

 

[ADSWNJ]

Hi Cras - can you tell me a bit more about Glideslope and HAC. I've not flown the Shuttle yet, so I have assumed that those tools are Shuttle-only.

Can you do a quick play-by-play for an XR-5 deadstick reentry and landing at Wideawake, using these tools?