Project XR2 Ravenstar - Mk II

[insane_alien]

well i suppose if you put it like that... i still like the idea of being able to tweak power supply to various sub systems. gives me more switches to press.

 

[Sky Captain]

Since XR2 runs on Naquadah rocket fuel I think it also uses Naquadah generator for electrical power so there is no worries about running out of electricity.

What I would like to see in XR2 Mk2 is some random system failures forcing you to do repair or switch to backup systems or abort mission. For example engine failure before final orbital insertion forcing you to fly unplanned suborbital trajectory to land on another base to save your crew or APU failure leaving only RCS to manage your reentry and atmospheric flight. Although I have no idea if it`s even possible to model it without rewriting the whole code.

 

[Lunar_Lander]

@dbeachy1: Thanks ! I think that such an advanced spacecraft as the XR2 should not allow to kill anybody of the crew by improper operation of the doors.

@insane_alien: Somebody once said something like that his request for internal systems must be the zillionth one . But I also share that thought and I'd like to see some more switches to throw in the future. Although it is supposed to be a high-power undepletable reactor, it has to have control elements. The suggestions of a failure logic is also an interesting one.

Could we maybe have an additional small bay for scientific instruments? STS-2 had some cameras and microwave detectors in the payload bay, but I would rather have these installed permanently without occupieing a payload bay slot. So I'd like to have a box with a moving door on one of the sides of the vehicle. Maybe also with a camera, which saves photos to a folder in the Orbiter directory when activated .

 

[halcyon]

Any updates, as insignificant as they may be?

 

[dbeachy1]

No updates to report. Unfortunately the mk II is on hold for the time being due to RL commitments that Steve and I have. But work will resume at some point. In any case, the XR2 Mk I (and other XR vessels as well) will be updated for compatibility with the new Orbiter release as necessary.

 

[halcyon]

Really looking forward to the working VC.
Haven't heard anything in 3 months, any progress?

 

[DarkWanderer]

A small note, but a major error: real life aerospace products always have a safety margin on all of the structural parameters. It usually lies in the range from 1.5-2 (military aircraft) to 3-5 (civil aircraft). So, XR2 breaking just when the needle is hitting the red mark looks at least strange.

 

[dbeachy1]

The Mk II is still on hold. Currently I'm working on the next XR patch releases to make them fully compatible with the Orbiter beta, particularly Orbiter_ng.

 

[halcyon]

Will the Mk2 be released before 2010?

 

[silent_protagonist]

A small note, but a major error: real life aerospace products always have a safety margin on all of the structural parameters. It usually lies in the range from 1.5-2 (military aircraft) to 3-5 (civil aircraft). So, XR2 breaking just when the needle is hitting the red mark looks at least strange.

Question: are you talking about safety margins in the design of the aircraft or on the gauges in the cockpit? From a design perspective, safety margin refers to designing a component to handle more stress than you expect it to need, it has nothing to do with how those stresses are reported to the pilot. On the other hand I have no idea what kind of margins are built into cockpit indicators; I'm not a pilot myself. So you may be right there. (although, for instance in a car, I'd much rather have a fuel gauge that reports the actual fuel level, with a warning light that comes on at two gallons, rather than a gauge that reads zero at two gallons)

It's also worth noting that the XR vehicles do give you warnings before they reach there limits. For instance, I set off the wing loading alarms all the time when I'm maneuvering at low altitude without damaging the wings. Granted, they don't give you a lot of warning but it's enough to fix the problem if your paying attention.

P.S. Glad the hear there's some development happening, at least, and I'm looking forward to the mkII whenever that comes.

 

[DarkWanderer]

Question: are you talking about safety margins in the design of the aircraft or on the gauges in the cockpit?

What is "safety margin" if cockpit gauges allow you to use 100% (not 50%+50% safety backup) of stress resistance?

From a design perspective, safety margin refers to designing a component to handle more stress that you expect it to need, it has nothing to do with how those stresses are reported to the pilot. On the other hand I have no idea what kind of margins are built into cockpit indicators; I'm not a pilot myself. So you may be right there. (although, for instance in a car, I'd much rather have a fuel gauge that reports the actual fuel level, with a warning light that comes on at two gallons, rather than a gauge that reads zero at two gallons)

Such a safety margin is applied only to structural limits, but it's always there. 2 reasons for it:
1.Random factor compensation - If you have a gauge marked for actual stress limit and push it on, and then suddenly get into a turbulence zone (which can give as much as 10-15% full lift load) - that's an instant death.
2.Wear and tear - airframe strength degrades over time, and you can't say when the actual stress limit goes below the painted red line.
And that applies to engineering in any area.

It's also worth noting that the XR vehicles do give you warnings before they reach there limits. For instance, I set off the wing loading alarms all the time when I'm maneuvering at low altitude without damaging the wings. Granted, they don't give you a lot of warning but it's enough to fix the problem if your paying attention.

Well, we can say there's currently a margin of 33%. And yes, a better warning (annoying tone like in X-Plane, when you're exceeding AoA) will do. Or something like that.

 

[silent_protagonist]

Such a safety margin is applied only to structural limits, but it's always there. 2 reasons for it:
1.Random factor compensation - If you have a gauge marked for actual stress limit and push it on, and then suddenly get into a turbulence zone (which can give as much as 50% full lift load) - that's an instant death.
2.Wear and tear - airframe strength degrades over time, and you can't say when the actual stress limit goes below the painted red line.
And that's what you see on any craft IRL. So, this one worth revisiting.

Ok, I see what your saying, and it does make sense. Although even when you do exceed the limits on the XR vessels you still have a random chance of avoiding damage for a short time (about as close as we can get in Orbiter to simulating turbulence, age, or manufacturing defects, etc, I think). But I agree that the margins do seem a bit narrow in areas.

 

[tblaxland]

As a matter of interest, I recall reading in Wayne Hale's blog that NASA uses a safety factor of 1.4 for human spaceflight:
http://wiki.nasa.gov/cm/blog/waynehalesblog/posts/post_1229459081779.html

 

[Hielor]

And yes, a better warning (annoying tone like in X-Plane, when you're exceeding AoA) will do. Or something like that.

That would be called the "stall warning horn"....

 

[DarkWanderer]

That would be called the "stall warning horn"....

I meant the type of sound, not alarm condition.
In F-15 over-G is sounded by master alarm+voice assistant at 7G, but the airframe maintains integrity on up to 13-14G (famous low-alt pullout case).
No, i'm not a pilot But these things are familiar to me.

As a matter of interest, I recall reading in Wayne Hale's blog that NASA uses a safety factor of 1.4 for human spaceflight:

Yeah, and the XR2 seems more like a commercial craft, rather than a thing that gets essentially rebuilt from scratch for every flight.
So - I'm not insisting, but shifting the lower boundary of wing destruction area up a bit would be good. IMHO.

 

[agentgonzo]

This has probably been mentioned, but the XR2 has problems with the new atmospheric modeling in the new Orbiter betas. When you get into the thermosphere (which is very high temperature, but very low density), the hull temp of the XR2 will increase to match it ending up with it exploding. I think this got mentioned in the bugs for the orbiter beta, but it's a problem with the XR2 (and UMMU I think).

Just thought I'd mention it as I can no longer get into LEO properly without exploding :-(

 

[TSPenguin]

That is already fixed, as well as nearly all other issues. Only one remains but that is very non-critical.
A new version can be expected tuesday.

 

[Nemoricus]

I've been using the XR series for a short time and consider them among the best well-done vessels for Orbiter. Truly, they are fabulous spacecraft.

I have a pair of suggestions to make. If they've been made before, I apologise. I haven't read through this entire thread to see what's been suggested.

1. Ability to use external power for hydraulics: I like to conserve APU fuel as much as possible. If there were a way to use an external power source when docked or landed, it would go a ways to help conserve the APU fuel for when it's needed.

2. Allow the crew to survive for a short time if the cabin decompresses, if they're wearing space suits.

However, these are fairly minor and you can disregard them if you want to.

 

[dbeachy1]

To reiterate what TS stated, XR patch releases are in the works to fix any compatibility issues with the Orbiter beta. The new XR versions will be released for public testing when the Orbiter release candidate is released.

 

[yagni01]

Ability to use external power for hydraulics: I like to conserve APU fuel as much as possible. If there were a way to use an external power source when docked or landed, it would go a ways to help conserve the APU fuel for when it's needed.

Since the flight controls use hydraulic actuators, external power would not make sense. If you were landed or docked, you can open the fuel hatch to top off your APU fuel if desired.