XCOR and the Lynx rocket

[Lars-J]

Plus, an optically flat windshield provides a less distorted picture for a space tourist's eyeball or a scientific instrument (XCOR's two markets).

Not if you have two windshields, now you get the worst of both worlds. I see some practical reasons for it, but it strikes me as very... inelegant? None of the other examples listed have two windshields stacked of such different spacing and shape.

I know the holy works of "Saint Greason" should not be questioned lest you open yourself for attack , but curious minds do wonder sometimes.

I look forward to seeing it fly - sometime soon, I hope. Two months of progress should have been done since the latest pictures.

The other's examples either didn't went to vacuum or the diameter of the pressure vessel wrt the window sized was much smaller. The inner glass has to be curved because it is part of the pressure vessel . The external is straight because doing glass heat shields curves is terribly expensive.

The X-15 and SR-71 went pretty darn high up, even if they didn't reach the same altitude. But the cockpit was pressurized, *and* the crew were sitting in pressure suits.

XCOR chooses to do it this way, but that doesn't mean it *has* to be done that way. Shuttle dind't have a round bubble inside the cockpit windows. Cost may be a primary factor for XCor in this instance - But it can be done. Pressurized hulls can have flat windows - see every manned spacecraft ever flown.

[john smith 19]

I wonder, exactly how expensive?

NASA formed  (IIRC) a small "Applied Physics" team to develop various tools, gadgets and processes to support Shuttle maintenance. One of them was  a device that used a prism to measure in detail surface damage to the Shuttle transparencies, to determine if they could be re-ground or if they were unsalvageable.

IIRC saving 1 layer of 1 panel saved somewhere between $20-50k (Sorry it's been a while and it was just one of those neat details I filed away).

This is for flat transparencies ultrasonically bonded to each frame.

I'm sure someone can supply the size of the Shuttle cockpit windows. Usual caveats, it's a NASA programme but I doubt there are many suppliers of this sort of material. Very clear. ground smooth to eliminate stress concentrations at the surface and capable of high temperatures.

[Rocket Science]

They are also saving the weight and cost of building a pressure vessel that has to contain windows.  The outer panes will be for aero and thermal requirements. Their attempt is to separate the two is interesting and the sphere idea seems to be borrowed from submersibles... From my pilot’s perspective vision distortion and magnification for depth perception would be interesting to view first hand. They may use a HUD and synthetic vision for all we know for runway approach details, air data and altitude...

[Elmar Moelzer]

They are also saving the weight and cost of building a pressure vessel that has to contain windows.  The outer panes will be for aero and thermal requirements. Their attempt is to separate the two is interesting and the sphere idea seems to be borrowed from submersibles... From my pilot’s perspective vision distortion and magnification for depth perception would be interesting to view first hand. They may use a HUD and synthetic vision for all we know for runway approach details, air data and altitude...

I don't think that the curved window will cause distortions as long as the thickness of the glass (or whatever it is) remains the same over the entire curvature. I mean there are helicopters with curved windows, have been for decades.

[Rocket Science]

They are also saving the weight and cost of building a pressure vessel that has to contain windows.  The outer panes will be for aero and thermal requirements. Their attempt is to separate the two is interesting and the sphere idea seems to be borrowed from submersibles... From my pilot’s perspective vision distortion and magnification for depth perception would be interesting to view first hand. They may use a HUD and synthetic vision for all we know for runway approach details, air data and altitude...

I don't think that the curved window will cause distortions as long as the thickness of the glass (or whatever it is) remains the same over the entire curvature. I mean there are helicopters with curved windows, have been for decades.

I'm sure Jeff and the team have this covered...

Edit to add: Remember it will a lot thicker than a helo windscreen...

[Moe Grills]

I hate doing this, especially after today's tragedy, but how will the loss of life on the SS2 affect the development of the Lynx?
In essence, XCOR are now the only active space tourism vehicle developers and the Lynx the only viable space tourism vehicle left. The FAA and Richard Branson may effectively clip the wings of Virgin Galactic for a long time, and this may effect Lynx development and funding too.

[zt]

new photo posted.

http://www.xcor.com/blog/interstellar1/

[TrevorMonty]

Actually Blue are also targeting suborbital market, should see something happen within next year.
.

[Moe Grills]

new photo posted.

http://www.xcor.com/blog/interstellar1/

I pray that it's a safe design and careful assembly.

[Joel]

Can the Lynx fly unmanned? If not, could such an ability be added?

[Moe Grills]

Can the Lynx fly unmanned? If not, could such an ability be added?

Why?

[Joel]

Can the Lynx fly unmanned? If not, could such an ability be added?

Why?

To mitigate risks until during the test phase. Cf. F9R test failure (which was not a major setback for SpaceX) and the recent SpaceShipTwo failure.

[Moe Grills]

Can the Lynx fly unmanned? If not, could such an ability be added?

Why?

To mitigate risks until the test phase. Cf. F9R test failure (which was not a major setback for SpaceX) and the recent SpaceShipTwo failure.

Commendable purpose, agreed.

as far as unmanned mode? Well....automatic pilots have been around for something like 100 years since Mr. Sperry affixed a crude gyroscopic AP device to a primitive aircraft.
And I don't have to tell you that today's computerized systems are far superior to the good old analog automatic pilots.

The means are there in theory, but motive and opportunity?

[Joel]

The means are there in theory, but motive and opportunity?

Not even considering the human dimension, it should be clear from the VG failure that a crash on a manned test flight could pose an existential threat to a company such as XCOR (without Branson's deep pockets). Motive enough?

[mheney]

People are talking in this and the SpaceShipTwo threads as if an autopilot is a simple piece of technology that you can bolt in under the dash (next to the 8-track player) and have it fly a vehicle through a test program - the purpose of which is to characterize the performance of the vehicle and find out where the edges of the envelope are.  It turns out that people are much better at flying by "feel" than computers are, which is what you need to do to learn what the flight characteristics are.

This was 100% true 30 years ago; it may be 100% false 50 years from now, it is what it is today.

[Joel]

I don't think anyone is claiming that it's easy to "bolt in an autopilot". But a retrofit should be feasible and not doing it from the onset was probably a bad design decision. In hindsight.

[Lars-J]

I don't think anyone is claiming that it's easy to "bolt in an autopilot". But a retrofit should be feasible and not doing it from the onset was probably a bad design decision. In hindsight.

Why? This is designed as a piloted air/spacecraft that will never fly unmanned - and it is being done on a budget. And they will be gradually expanding the envelope, not full up missions from the start.

So please don't go around suggesting knee-jerk "safety features".

[Kryten]

I don't think anyone is claiming that it's easy to "bolt in an autopilot". But a retrofit should be feasible and not doing it from the onset was probably a bad design decision. In hindsight.

Why? This is designed as a piloted air/spacecraft that will never fly unmanned - and it is being done on a budget. And they will be gradually expanding the envelope, not full up missions from the start.

So please don't go around suggesting knee-jerk "safety features".

All of those points could be applied to DC, yet that has an autopilot, and said autopilot has already prevented what would probably have been a serious injury or worse.

[Vultur]

I'm not qualified to judge whether an autopilot is a good idea or not, but either way, one accident should not determine that one way or the other - VG's accident doesn't really tell us anything about Lynx.

If autopilots are a good idea to prevent risk to test pilots, then that should be broadly true, not necessarily specific to suborbital tourism, and it would have been true before the accident too.

[hop]

All of those points could be applied to DC, yet that has an autopilot, and said autopilot has already prevented what would probably have been a serious injury or worse.

DC was a very much more expensive program, with very different requirements. For DC, there are strong reasons to want the vehicle to be able to fly a full orbital flight autonomously. It also needs to have guidance capable of flying the entry and managing the trajectory to get to the landing site autonomously, so going the last mile is not a huge additional effort.

This is very different from vehicles like SS2 and Lynx, which are meant to be high performance aircraft. They don't need to fly autonomously for their nominal operations, and the affordability is supposed to come by being developed and operated like an aircraft.

IMO, this rush to say that vehicles like SS2 and Lynx should be tested unmanned is deeply misguided. As I said in the other thread, losing an airframe is a major setback in this kind of program. If your confidence in the vehicle is so low that it's unacceptable to fly people, the risk of losing an airframe is unsustainable high.

It is demonstrably possible to develop high performance aircraft with a low rate of vehicle loss. Using rockets doesn't fundamentally change this. It's too early to say what the lessons of the SS2 tragedy will be, but I'm pretty confident that it won't be "the only safe way to develop a rocket plane is to fly without crew".