XCOR and the Lynx rocket

[Space Ghost 1962]

Randy's right up to this point. But Chris can't be denied either.

I think that with SS2 anomaly there may be pressure to fly and qualify in novel environments/envelope unmanned first.

This might not have saved SS2, because it WAS flown successfully manned for over a year. Who is to say that after you qualify the vehicle for "manned", that then it has another anomaly, which you decide should have been checked for in "unmanned" testing. Point being that there are limits on such bounded testing.

I think the issue is more about the cost of testing driving unwise business decisions to limit the extent of testing.

If unmanned testing can lower the cost of testing while increasing the frequency AND severity (test to near destruction), it has a place in increasing effectiveness here.

But Randy's point will still remain - you must test with people, with pilots. There will be anomalies.

[Robotbeat]

Yeah, I think you'd test with pilots eventually (before passengers), but the platform itself is incredibly dangerous to begin with and in my opinion it's better to get as many bugs out before risking life. That's part of the advantage of reusability: test flights are cheap.

[QuantumG]

The XCOR solution is to slowly expand the envelope the way aircraft have been tested for decades. After extensive ground testing of the engines, they'll be doing integrated vehicle hold-down testing, followed by taxi tests (which is probably the first time crew will be in the vehicle while the engines are firing), followed by touch-and-go testing, followed by flying around at low altitude, followed by higher altitude flights, etc, etc.

[Moe Grills]

  Let's throw in a real world scenario: a flat spin.

Are the pilots (pro or rookie) for the Lynx rocket plane being trained how to deal with a potentially deadly flat spin? I imagine that the Lynx rocket plane is fully capable of entering into that dangerous circumstance.

[QuantumG]

XCOR's Pilots: http://www.xcor.com/team/pilots.html

Kinda thinking they've forgotten more about flying than we've ever known.

[hop]

Yeah, I think you'd test with pilots eventually (before passengers), but the platform itself is incredibly dangerous to begin with and in my opinion it's better to get as many bugs out before risking life. That's part of the advantage of reusability: test flights are cheap.

Test flights can be cheap*, but airframes are not. If you can only afford to build a few, losing them is a big problem whether or not anyone is on board. Flying uncrewed is likely to increase the risk of losing a vehicle significantly.

You also introduce some significant regulatory and operational hassles. Lynx with a pilot flies as an experimental aircraft. While I don't know for certain, it seems very unlikely you would be able to fly an equivalent vehicle as a UAV from Mojave. You would probably need a dedicated range like Spaceport America, which either puts you far from your production facility, or puts your production facility in the middle of nowhere.

* Not so much in the case of SS2 with a motor refurb every flight.

[jongoff]

Yeah, I think you'd test with pilots eventually (before passengers), but the platform itself is incredibly dangerous to begin with and in my opinion it's better to get as many bugs out before risking life. That's part of the advantage of reusability: test flights are cheap.

I still liked the incredulity this idea (turning SS2 or Lynx into a UAV for its flight test program) gets from people with actual experience designing, building, and operating high performance UAVs.

~Jon

[Robotbeat]

Yeah, I think you'd test with pilots eventually (before passengers), but the platform itself is incredibly dangerous to begin with and in my opinion it's better to get as many bugs out before risking life. That's part of the advantage of reusability: test flights are cheap.

I still liked the incredulity this idea (turning SS2 or Lynx into a UAV for its flight test program) gets from people with actual experience designing, building, and operating high performance UAVs.

~Jon

Hey, I would've designed SS2 or Lynx different in the first place (because of my biases). Neither could be easily modified to be autonomous or remote at this point.

[Joel]

If you add a capability of fly-by-wire and flying remotely, you might later be able to operate the rocket plane with a single pilot and have one more paying passenger.

[Lars-J]

If you add a capability of fly-by-wire and flying remotely, you might later be able to operate the rocket plane with a single pilot and have one more paying passenger.

You have a talent for comedy. "Hey, we don't trust the plane enough to fly it ourselves, but go ahead and strap in!"

Remote control isn't a cure-all, despite what you recent UAV converts might think. If you think that it is so dangerous to fly a prototype then you probably haven't managed the risk properly. A program like Lynx or SS2 won't last if unmanned prototypes keep falling out of the sky either.

[Joel]

If you add a capability of fly-by-wire and flying remotely, you might later be able to operate the rocket plane with a single pilot and have one more paying passenger.

You have a talent for comedy. "Hey, we don't trust the plane enough to fly it ourselves, but go ahead and strap in!"

Remote control isn't a cure-all, despite what you recent UAV converts might think. If you think that it is so dangerous to fly a prototype then you probably haven't managed the risk properly. A program like Lynx or SS2 won't last if unmanned prototypes keep falling out of the sky either.

I meant having one pilot instead of two, but I guess that would only apply to SS2, since Lynx only has one pilot to begin with. For Lynx, ability for remote landing would add extra safety. If something happens to the pilot, the plane can still come down safely. So investing in remote piloting during test phase could translate into lower cost and/or extra safety during operational phase. Two birds with one stone.

Also, try being respectful. I develop and implement algorithms for model-based control and trajectory optimization for a living. My most important application is flight control of UAVs (rigid wing + quadcopters).

[wtrix]

  Let's throw in a real world scenario: a flat spin.

Are the pilots (pro or rookie) for the Lynx rocket plane being trained how to deal with a potentially deadly flat spin? I imagine that the Lynx rocket plane is fully capable of entering into that dangerous circumstance.

Because Lynx has RCS on board, the pilot is not limited to using aerodynamic surfaces only for a control of the craft. Thus, exiting flat spin or transfering to normal spin is easier.

[Rocket Science]

  Let's throw in a real world scenario: a flat spin.

Are the pilots (pro or rookie) for the Lynx rocket plane being trained how to deal with a potentially deadly flat spin? I imagine that the Lynx rocket plane is fully capable of entering into that dangerous circumstance.

Because Lynx has RCS on board, the pilot is not limited to using aerodynamic surfaces only for a control of the craft. Thus, exiting flat spin or transfering to normal spin is easier.

If you are comparing it to SS2 which has nose and wing tip RCS...

[wtrix]

  Let's throw in a real world scenario: a flat spin.

Are the pilots (pro or rookie) for the Lynx rocket plane being trained how to deal with a potentially deadly flat spin? I imagine that the Lynx rocket plane is fully capable of entering into that dangerous circumstance.

Because Lynx has RCS on board, the pilot is not limited to using aerodynamic surfaces only for a control of the craft. Thus, exiting flat spin or transfering to normal spin is easier.

If you are comparing it to SS2 which has nose and wing tip RCS...

So? Every airframe is differnet. Some are even immune to flat spin. SS2 has possibly easier time coming out of flat spin through feathering instead of using RCS. However as you correcly point out, RCS may not be powerful enough to force the aircraft into dive. Instead some oscillating and playing together with aerodynamic surfaces may be needed.

Nevertheless. Flat spin training is definately needed.

[Rocket Science]

  Let's throw in a real world scenario: a flat spin.

Are the pilots (pro or rookie) for the Lynx rocket plane being trained how to deal with a potentially deadly flat spin? I imagine that the Lynx rocket plane is fully capable of entering into that dangerous circumstance.

Because Lynx has RCS on board, the pilot is not limited to using aerodynamic surfaces only for a control of the craft. Thus, exiting flat spin or transfering to normal spin is easier.

If you are comparing it to SS2 which has nose and wing tip RCS...

So? Every airframe is differnet. Some are even immune to flat spin. SS2 has possibly easier time coming out of flat spin through feathering instead of using RCS. However as you correcly point out, RCS may not be powerful enough to force the aircraft into dive. Instead some oscillating and playing together with aerodynamic surfaces may be needed.

Nevertheless. Flat spin training is definately needed.

From my pilot’s perspective one can never train enough for unusual attitudes... I presume you are speaking about upright and inverted flat spins... A simple drogue chute can be incorporated...

[Star One]

Bleeding edge aircraft are still flown manned for a very good reason, you'll probably still find that even the most sophisticated of vehicles are tested in this way because if something goes wrong which they often do when testing at the limits of technology that a man is more likely to be able to keep the vehicle flying and bring it home safely than even the best automated system. I would put good money on it probably being the case that for example when the LRS-B, which is probably going to be the most sophisticated test program at the moment,  gets declassified that it has been tested & flown by pilots not machines.

So I don't see why this or SS2 should be any different in that respect, I've still got more faith in a person still than a machine in these cases.

[Lars-J]

If you add a capability of fly-by-wire and flying remotely, you might later be able to operate the rocket plane with a single pilot and have one more paying passenger.

You have a talent for comedy. "Hey, we don't trust the plane enough to fly it ourselves, but go ahead and strap in!"

Remote control isn't a cure-all, despite what you recent UAV converts might think. If you think that it is so dangerous to fly a prototype then you probably haven't managed the risk properly. A program like Lynx or SS2 won't last if unmanned prototypes keep falling out of the sky either.

I meant having one pilot instead of two, but I guess that would only apply to SS2, since Lynx only has one pilot to begin with. For Lynx, ability for remote landing would add extra safety. If something happens to the pilot, the plane can still come down safely. So investing in remote piloting during test phase could translate into lower cost and/or extra safety during operational phase. Two birds with one stone.

Also, try being respectful. I develop and implement algorithms for model-based control and trajectory optimization for a living. My most important application is flight control of UAVs (rigid wing + quadcopters).

Ok, so maybe the sarcasm was a bit over the top. And I did assume that you mean the Lynx, being in this thread. But still...

There is a reason that no passenger carrying aircraft have ever been flown for the first time unmanned. As far as I know. Not even piloted military aircraft. It just doesn't happen.

Given the rationale that you mention, you would think that big manufacturers like Boeing or Airbus with billion dollar developments, their fly-by-wire systems, AND auto-pilots well capable of flying the thing - They STILL never do unmanned test flights. Why? Because they damned well know that if their expensive plane is that likely to fall out of the sky that they cannot risk a pilot, then they shouldn't fly. Period.

But this is a space-plane you say. All different? Perhaps. But Lynx is a system that they will be able to do very gradual test envelope expansion on. Even more so than SS2 which requires it to be dropped from a carrier aircraft.

[Joel]

Given the rationale that you mention, you would think that big manufacturers like Boeing or Airbus with billion dollar developments, their fly-by-wire systems, AND auto-pilots well capable of flying the thing - They STILL never do unmanned test flights. Why? Because they damned well know that if their expensive plane is that likely to fall out of the sky that they cannot risk a pilot, then they shouldn't fly. Period.

But this is a space-plane you say. All different? Perhaps. But Lynx is a system that they will be able to do very gradual test envelope expansion on. Even more so than SS2 which requires it to be dropped from a carrier aircraft.

I think it's naive to believe that crashes can be avoided, even "gradually expanding the test envelope". Which development of supersonic aircraft has been without crashes? A fatal crash (like SS2's) could spell the end of the Lynx program, an unmanned crash probably less so. Multiple fatal crashes most definitely would. The cost of a crash is not just the cost of building new hardware. Concerning that they "They STILL never do unmanned test flights", they obviously do unmanned test flights of unmanned vehicles (a Reaper isn't exactly cheap), so it's not like it's impossible. Is the risk of crash higher? Possibly.

[Lars-J]

Given the rationale that you mention, you would think that big manufacturers like Boeing or Airbus with billion dollar developments, their fly-by-wire systems, AND auto-pilots well capable of flying the thing - They STILL never do unmanned test flights. Why? Because they damned well know that if their expensive plane is that likely to fall out of the sky that they cannot risk a pilot, then they shouldn't fly. Period.

But this is a space-plane you say. All different? Perhaps. But Lynx is a system that they will be able to do very gradual test envelope expansion on. Even more so than SS2 which requires it to be dropped from a carrier aircraft.

I think it's naive to believe that crashes can be avoided, even "gradually expanding the test envelope". Which development of supersonic aircraft has been without crashes? A fatal crash (like SS2's) could spell the end of the Lynx program, an unmanned crash probably less so. Multiple fatal crashes most definitely would. The cost of a crash is not just the cost of building new hardware. Concerning that they "They STILL never do unmanned test flights", they obviously do unmanned test flights of unmanned vehicles (a Reaper isn't exactly cheap), so it's not like it's impossible. Is the risk of crash higher? Possibly.

Obviously. You test as you fly, so it makes sense to test fly UAV's unmanned. And manned aircraft manned. See the pattern?

[QuantumG]

A fatal crash (like SS2's) could spell the end of the Lynx program, an unmanned crash probably less so. Multiple fatal crashes most definitely would. The cost of a crash is not just the cost of building new hardware.

Do go on.. how do you imagine crashes during the flight testing phase of the vehicle could end the Lynx program?