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42 minutes ago, mikegarrison said:

It depends on the type of airplane. For instance, small general aviation airplanes have no requirement for this (which should be obvious because some have only one engine).

Part 25 airplanes (large transport) have be able to maintain a positive rate of climb even with one engine out. This is usually the sizing criterion for the engines and also the vertical stabilizer, which has to be able to handle the asymmetric thrust.

Obviously all engines out is a problem. (cf. US Airways flight 1549)

There are also requirements for what is known as ETOPS, which is how the airplane performs if an engine fails while a twin-engine airplane is out over the ocean and has no place to land.

Yes, ETOPS is because they have to fly lower with one engine out on a two engine plane and this increases drag, Tail is so large to help you fly with one engine to but this is mostly at low speeds. 
So an flight path over water have to have enough margin so you can reach an emergency landing spot with one engine out at any part of the flight. 

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12 minutes ago, tater said:

Yeah, while a fascinating concept (who wouldn't want a 30 min flight to Australia?), it seems pretty disconnected from reality. It's a fun thought experiment, but I can't even imagine that level of reliability given how insanely safe air travel is—and the vast majority of air crashes are pilot error, so there is room to improve air safety (which is hard to imagine).

Air travel hasn’t always been as insanely safe as it is now. We’ll see what SpaceX can do about their safety. How about a VTHL Starship with foldable wings for P2P flights? 

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1 minute ago, Delta dart said:

Can we lose 3 starships in 2 days? Maybe get a world record for most spacecraft lost by a single company in 2 days?

The definition of 'lost' is different in each case. SN9 was destroyed in an unintentional but certainly not unexpected mishap, SN5 is being deliberately scrapped, and SN7.2 is being deliberately tested to destruction. SN7.2 isn't a spacecraft anyway, it's a ground test article.

So no, I don't think this would qualify for an obscure world record attempt.

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55 minutes ago, mikegarrison said:

This is part of why I consider the Starship point-to-point commercial passenger idea laughable. The level of safety and reliability required for commercial passenger transport is so far higher than that demanded for something like flight to the ISS that either Musk has no clue or else he's just trolling for interest.

Unless the Starship is just a prototype of a supergiant seaplane floater....

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34 minutes ago, sh1pman said:

Air travel hasn’t always been as insanely safe as it is now. We’ll see what SpaceX can do about their safety. How about a VTHL Starship with foldable wings for P2P flights? 

I have trouble imagining P2P with propulsive landing being 1940s airline safety level.

Current air travel is 10X safer than when I was a kid, and it was pretty safe then.

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Spoiler

They should use the decommissioned tanks for a probabilistic sacrifice.

Say, probability of a tank explosion is 1:1.
They should explode a decommissioned tank, so the probability gets full up, and the other tank won't explode in flight.

 

Edited by kerbiloid
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29 minutes ago, Delta dart said:

All the other tanks sprung leaks before exploding so will this one have a spectacular explosion or is it done?

That is not true. One of their early ones exploded before it leaked. (This is not desired behavior for a tank, and it is clear that they have changed their design criteria to get a proper "leak before burst" behavior.)

Edited by mikegarrison
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On 2/2/2021 at 1:45 PM, tater said:

The flip maneuver comes so very late (to minimize props) that there seems to be zero time for redundancy (they have 3 engines, only light 2).

I wonder if they could sacrifice some payload, up the header tank volumes, and then do the flip earlier, and with 3 engines. Then shut down engines as needed?

Might be the only time I quote myself, but in this case ^^^...

 

 

 

Edited by tater
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What I find interesting is that there's been.....I dunno, 60? years of space flight, but Starship's landing flight profile is pretty unique and thus its amazing to see. SN8s first attempt was probably more representative to take. Helped of course, by SpaceX not revealing too much about it beforehand either. I dare say, some or other spaceship has done similar on a Moon or Mars landing we don't know about and didn't see because there's no cameras etc just computer simulated graphics maybe?

The Space Shuttle comparison is interesting too - of course we typically see and are able to easily visualise the later stages of its landing which looks similar to a plane's (but if we also appreciated the speeds and descent rates, is clearly somewhat different) but the earlier stages, eg retrofiring then the big sweeping S turns and 270deg phase totally unlike a capsule splashdown. I bet that NASA took years of deliberation to develop and refine the flight profile and did a bunch of testing too - but that's one of the key differences between NASA and SpaceX.

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50 minutes ago, kerbiloid said:
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They should use the decommissioned tanks for a probabilistic sacrifice.

Say, probability of a tank explosion is 1:1.
They should explode a decommissioned tank, so the probability gets full up, and the other tank won't explode in flight.

 

I've been trying this method with lottery tickets and it's still not working 

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27 minutes ago, paul_c said:

What I find interesting is that there's been.....I dunno, 60? years of space flight, but Starship's landing flight profile is pretty unique and thus its amazing to see. SN8s first attempt was probably more representative to take. Helped of course, by SpaceX not revealing too much about it beforehand either. I dare say, some or other spaceship has done similar on a Moon or Mars landing we don't know about and didn't see because there's no cameras etc just computer simulated graphics maybe?

The Space Shuttle comparison is interesting too - of course we typically see and are able to easily visualise the later stages of its landing which looks similar to a plane's (but if we also appreciated the speeds and descent rates, is clearly somewhat different) but the earlier stages, eg retrofiring then the big sweeping S turns and 270deg phase totally unlike a capsule splashdown. I bet that NASA took years of deliberation to develop and refine the flight profile and did a bunch of testing too - but that's one of the key differences between NASA and SpaceX.

The key difference is who's money is being spent.  With SpaceX - we get to enjoy the spectacle...  Sadly with NASA every other 'interest' in receiving tax dollars would howl and scream, refusing to understand the process. 

 

It sucks when you are not allowed to make mistakes. 

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