DanG 1
Recommended Posts
[Reply]Do you honestly believe Scaled Composites didn't account for a W&B change with a new propulsion system? These guys aren't amateurs.
I know they did. There's a bird with a The dimensions of the ship and the center of gravity were already set. So the new engine had to be designed and engineered within those parameters.
This is pretty much the opposite of what is done and was necessary when they switched the engine. So what about the plane? Think it's going to handle the same? Same trim characteristics?
Scaled Composites weren't amateurs. But they were novices with rockets. This outside-the-box thinking allowed them to hit the home run with SpaceShipOne. It also has proven problematic with SS2. The motor designn that took SS1 to space was proven incapable of taking the larger SS2 anywhere near 60 miles up.
Are you suggesting that you can just put any motor you want on a plane? Or does the engineering require trade-offs where changes make it less efficient?
"Just put a new engine in" isn't that easy.
My wife is hotter than your wife.
DanG 1
Do you know that the new engine had a different mass and cg? Was the thrust vector different? Do you know if they adjusted ballast elsewhere in the vehicle to account for changes to the engine? Where are you getting your information?
- Dan G
- Dan G
Calvin19 0
pchapman
At least for the Space Shuttle Challenger, the official announcer did say, "obviously a major malfunction".
Very true.
Going over the cause of that and the millisecond by millisecond timeline of the disintegration is very interesting. No explosion at all. The thing just fell apart, like throwing a can of gasoline out of a car down the highway. Yeah, there is fire, but not an 'explosion'.
muff528 3
I vaguely remember that this was not an announcer per se. I think he was reporting progress of the launch and ascent while looking at telemetry data, etc. and was not actually watching it. Could be wrong, though ...been a long time..
ETA: Steve Nesbitt at Mission Control in Houston.
http://spaceflightnow.com/challenger/timeline/
ETA: Steve Nesbitt at Mission Control in Houston.
http://spaceflightnow.com/challenger/timeline/
wolfriverjoe 1,340
muff528I vaguely remember that this was not an announcer per se. I think he was reporting progress of the launch and ascent while looking at telemetry data, etc. and was not actually watching it. Could be wrong, though ...been a long time..
ETA: Steve Nesbitt at Mission Control in Houston.
http://spaceflightnow.com/challenger/timeline/
I agree that it's been a long time (so my memory could be wrong also).
I remember the shot of Mission Control, with all the controllers over their screens, trying to make sense of the data, trying to figure out what was going on, until one of them spotted a TV that was showing the long range camera view (the big cloud).
The look on his face as he realized that the entire vehicle was gone is something I will never forget.
"There are NO situations which do not call for a French Maid outfit." Lucky McSwervy
"~ya don't GET old by being weak & stupid!" - Airtwardo
"~ya don't GET old by being weak & stupid!" - Airtwardo
DanGDo you know that the new engine had a different mass and cg? Was the thrust vector different? Do you know if they adjusted ballast elsewhere in the vehicle to account for changes to the engine? Where are you getting your information?
I don't know. I can't even confirm that it isn't the same engine, but with a different fuel mix. What I was getting at is that the bird was designed with a certain type of engine in mind. The motor got them past Mach but hadn't gotten them anywhere near space.
My thing is whether they'll use the same type of motor in the next version. The power plant is going to be the most important decision. Did the hybrid show enough promise in terms of affordability, reliability, thrust and comfort? (The latter is important now. These paying customers probably won't appreciate an uncomfortable bumpy ride).
My wife is hotter than your wife.
DanGDo you know that the new engine had a different mass and cg? Was the thrust vector different? Do you know if they adjusted ballast elsewhere in the vehicle to account for changes to the engine? Where are you getting your information?
I don't know. I can't even confirm that it isn't the same engine, but with a different fuel mix. What I was getting at is that the bird was designed with a certain type of engine in mind. The motor got them past Mach but hadn't gotten them anywhere near space.
My thing is whether they'll use the same type of motor in the next version. The power plant is going to be the most important decision. Did the hybrid show enough promise in terms of affordability, reliability, thrust and comfort? (The latter is important now. These paying customers probably won't appreciate an uncomfortable bumpy ride).
My wife is hotter than your wife.
DanG 1
Since the preliminary investigation indicated that the engine had nothing to do with the crash, I don't see why they wouldn't use it. You don't spend millions designing a component, then throw it out because another component failed.
- Dan G
- Dan G
philh 0
One interesting question that has arisen is how did the pilot survive?
According to this report ( link below) he did not exit through the escape hatch.
So I presume he was left in the air as the vehicle borke up. But I presume after that he would not be connectedt to any oxygen supply. If he deployed quickly before b he went unconcisouss then he would have a real problem with the cold. But if he waited how did he stay consicouss?
I presume these pilots dont have AAD's on thier rigs.
So what do we think?
Also do the difficulties Virgin are having in making a much bigger craft than SS1 imply a company like XCOR whose lynx vehicle is much smaller and can only take 1 passenger is more viable?
http://news.nationalpost.com/2014/11/04/virgin-galactic-spaceshiptwos-surviving-pilot-managed-to-parachute-from-50000-feet-without-an-oxygen-mask/
According to this report ( link below) he did not exit through the escape hatch.
So I presume he was left in the air as the vehicle borke up. But I presume after that he would not be connectedt to any oxygen supply. If he deployed quickly before b he went unconcisouss then he would have a real problem with the cold. But if he waited how did he stay consicouss?
I presume these pilots dont have AAD's on thier rigs.
So what do we think?
Also do the difficulties Virgin are having in making a much bigger craft than SS1 imply a company like XCOR whose lynx vehicle is much smaller and can only take 1 passenger is more viable?
http://news.nationalpost.com/2014/11/04/virgin-galactic-spaceshiptwos-surviving-pilot-managed-to-parachute-from-50000-feet-without-an-oxygen-mask/
Andy9o8 0
normiss 622
That's bad ass. 
Andy9o8 0
normissThat's bad ass.
Dude owes lots of beer.
pchapman 261
I'll guess he just got lucky to not have been physically injured much in the breakup, and to wake up sufficiently in time once there was more oxygen in the air.
Explosive decompression and low temperatures wouldn't have been fun but not fatal. There certainly can be some time of confusion after unconsciousness due to lack of oxygen.
And unlike the article there are no ejection seats. He probably had a mask on in the aircraft - there are FAA regs in case of depressurization at very high altitudes, although it clearly wouldn't help if the main supply were gone, a bailout bottle were manually activated, or the mask stripped off during the breakup. Although the breakup was at Mach 1, the Equivalent Airspeed would have been "only" about 250 kts if at around 50,000', which brings the forces down.
Explosive decompression and low temperatures wouldn't have been fun but not fatal. There certainly can be some time of confusion after unconsciousness due to lack of oxygen.
And unlike the article there are no ejection seats. He probably had a mask on in the aircraft - there are FAA regs in case of depressurization at very high altitudes, although it clearly wouldn't help if the main supply were gone, a bailout bottle were manually activated, or the mask stripped off during the breakup. Although the breakup was at Mach 1, the Equivalent Airspeed would have been "only" about 250 kts if at around 50,000', which brings the forces down.
philh 0
Is a bail out bottle normal for high altitude test flying ?
ryoder 1,382
Andy9o8***That's bad ass.
Dude owes lots of beer.
The shoulder injury came from the opening shock?
Damn, that sucks!
I don't think he owes *any* beer;
He should be able to walk into any bar and *get* all the free beer he wants.
"There are only three things of value: younger women, faster airplanes, and bigger crocodiles" - Arthur Jones.
DanGSince the preliminary investigation indicated that the engine had nothing to do with the crash, I don't see why they wouldn't use it. You don't spend millions designing a component, then throw it out because another component failed.
No. Not unless you are unhappy with the performance of the propulsion system over the last 8 years. As I'd mentioned before, when the plane was built around that hybrid rocket, it's not like one can simply put in, say, a liquid fueled version without redesgning the airframe.
Even though the motor didn't fail, the motor also never worked the way it as supposed to. So what does someone do. "Hey, we had a catastrophic failure in the feathering system. So let's rebuild this this and pay attention to that feathering system design."
"We've noted from testing some issues with regard to the motor. Our choice of propulsion looks like it can't get us there."
"It didn't destroy the bird. I'm not interested in improving anything other than the matter that caused the catastrophe."
I'm having a very hard time thinking that this is how it works. The engineers now have the opportunity to implement every lesson learned (which may be to keep the old engine) in making an improved design. To suggest that they ignore all prior lessons learned and only do something about the feathering command just doesn't make sense to me.
My wife is hotter than your wife.
DanG 1
Maybe we're not communicating clearly. I thought you were implying that they should switch engines because of the break-up. That makes no sense. If they don't have an engine that can do the job, then obviously they need to improve it. But this test was intended to see whether the whole system, including the engine, would work together in a flight environment. They'll get what engine performance data they can, and use that independently. If the engine didn't perform to spec, then it needs to be fixed. If it did perform, then it passed the test. Tests have multiple objectives. You can meet none, all, or some of them, but often times they are independent.
- Dan G
- Dan G
[Reply] thought you were implying that they should switch engines because of the break-up
I never meant to imply that. My suggestion was that the motor has never worked as it should - just scaling up SS1's motor brought problems. Because the bird as already built, balanced, etc., just switching the engine type isn't feasible. Rather than scrapping SS2, the natural desire is to try to squeeze everything out of the powerplant and save the investment in the craft without scrapping the craft.
Now Virgin Galactic doesn't have that constraint. Which is why I'm wondering whether they'll choose a different powerplant to build the new one around.
My wife is hotter than your wife.
davjohns 1
Andy9o8
Thanks. I wondered how far he rode the canopy. Is it wrong that my first thought when I heard about this was to wonder if he set a new skydiving record?
I know it just wouldnt be right to kill all the stupid people that we meet..
But do you think it would be appropriate to just remove all of the warning labels and let nature take its course.
But do you think it would be appropriate to just remove all of the warning labels and let nature take its course.
philh 0
Anyone know the highest ever deployment of a canopy? If he deployed anywhere near the 50,000 ft altitude of the accident, maybe thats a record?
Andy9o8 0
The article suggests it was @ around 17K.
- Dan G
Share this post
Link to post
Share on other sites