Seen several comments along the lines of “SpaceX giving up on composites for BFS.” My bet is no, they haven’t.Although structure and fuel tanks will be stainless, it’s possible the “people tank” will still be CF structure. If they develop a CF all-contained module for passengers, it likely would be significantly lighter and cheaper than all that structure out of metal, just as it was for the interstage on F9. A CF “passenger module” or “payload module” could be inserted into appropriate space, whether at the top or as many are speculating based on BFH so far just above the engine bay, as needed for a crew, cargo, or tanker BFS (with only bigger tanks instead).
Looks like it's about to get placed on the can!
Engines currently on Starship hopper are a blend of Raptor development & operational parts. First hopper engine to be fired is almost finished assembly in California. Probably fires next month.
Aiming for 4 weeks, which probably means 8 weeks, due to unforeseen issues
As seen in photos thread, an official render of the completed BFH.
https://twitter.com/elonmusk/status/1081572521105707009https://twitter.com/elonmusk/status/1081575156990894082Am I the only one that doesn't know how interpret these tweets together?How can they expect to do flight tests in a month (or even 2) if the 'first hopper engine to be fired ... probably fires next month'?Also I still don't understand from Elon's answer if the Raptors already mounted on the hopper are working engines or not.
Quote from: AbuSimbel on 01/05/2019 02:58 pmhttps://twitter.com/elonmusk/status/1081572521105707009https://twitter.com/elonmusk/status/1081575156990894082Am I the only one that doesn't know how interpret these tweets together?How can they expect to do flight tests in a month (or even 2) if the 'first hopper engine to be fired ... probably fires next month'?Also I still don't understand from Elon's answer if the Raptors already mounted on the hopper are working engines or not.My takeaway (and for me it’s clear, but obviously subjective) is he used “engines” not bells, nozzles, or mockups, so those are actual engines mounted in there. However because they’ve changed materials (SX500 stainless steel for example) and potentially other things on a new iteration that has yet to be fired, they may not be the actual flight engines used for hopping.
Quote from: Johnnyhinbos on 01/05/2019 03:02 pmQuote from: AbuSimbel on 01/05/2019 02:58 pmhttps://twitter.com/elonmusk/status/1081572521105707009https://twitter.com/elonmusk/status/1081575156990894082Am I the only one that doesn't know how interpret these tweets together?How can they expect to do flight tests in a month (or even 2) if the 'first hopper engine to be fired ... probably fires next month'?Also I still don't understand from Elon's answer if the Raptors already mounted on the hopper are working engines or not.My takeaway (and for me it’s clear, but obviously subjective) is he used “engines” not bells, nozzles, or mockups, so those are actual engines mounted in there. However because they’ve changed materials (SX500 stainless steel for example) and potentially other things on a new iteration that has yet to be fired, they may not be the actual flight engines used for hopping.So if they want to fly the hopper in 1-2 months is it possible they intend to forgo acceptance testing of the engines on a test stand?
So if they want to fly the hopper in 1-2 months is it possible they intend to forgo acceptance testing of the engines on a test stand?Edit: or maybe they're going to use just a single engine at first as su27k suggested...
QuoteDo you think that for the production Starship they will return to FSW? Supposedly it delivers welds on stainless with better high temperature properties than more prosaic welding techniques. No, for FSW you need to use a much harder tougher metal as the stirring tool, and as hard and tough as Stainless steel becomes when cold-worked there really aren't any viable materials.If you want to go that route then ultrasonic welding (rubbing metal on metal at ~10-20kHz ~0.001mm oscillation) is the way to go. Doesn't ruin the strength of the cold-worked (tough and hard) stainless being welded like MIG or TIG or laser welding does.
Do you think that for the production Starship they will return to FSW? Supposedly it delivers welds on stainless with better high temperature properties than more prosaic welding techniques.