Amazing stuff. The blog post mentions tolerances in inches. Is Aerospace engineering done in inches or meters?
XB-1's wings are officially closed out
81–90 of 180 posts
Re: XB-1's wings are officially closed out
#82Earlier quoted context omitted.
Is it specifically to demonstrate that they can make a quiet aircraft then? I think I'm curious specifically whether this is more about internal R&D and building systems, or if it's meant to demonstrate they have the capability to to create a performant supersonic aircraft, which they can take to potential investors.
This demonstrator is a 1/3 scale model of their final design. It allows them to prove their exact final design will be quiet, along with verifing the rest of the aerodynamics.
Any idea how often the final design and the prototype don't match in terms of volume and aerodynamics? I would have assumed that those parts are the easiest to model with high confidence.
Re: XB-1's wings are officially closed out
#83Earlier quoted context omitted.
I hate points like this. Pretty much all technology starts out for rich people. I mean if you don't have supersonic flight at all its technology will not improve either, neither will the economics of scale. Air travel itself is already only for the rich, and travel in general is mostly for the rich, if you want to look at it from the poorest in the world. Elon made this point the best with Tesla, and in 10-20 years t…
They are though. Tesla is a horrible example, electric cars have better fuel economy, so should have a lower TCO for daily users in the long run. Which has always explicitly been Tesla's goal in the long run. This plane, while awesome, is not a Tesla, it's never going to be as cheap as a commercial flight, and it's certainly not going to make the world a better place.
I was not talking about Boom Overture in particular but Super sonic flight. Boom is just the first that could bring it back and innovation can happen from there. Do we really want a world in 100 years we are still flying subsonic?
And if people use it makes the world a better place by some definition. The worst you could say that it used more fuel.
Re: XB-1's wings are officially closed out
#84I'm surprised by the assembly tolerances. .05-.1"
The F-35 is assembled to .003"
The usage of control cables and pulleys is odd. I would have expected hydraulic/electric actuation in a Mach 2+ aircraft.
Re: XB-1's wings are officially closed out
#85I keep wondering if planes could benefit from the new materials developed by SpaceX. If they really have a stainless steel that's significantly lighter, it could be a game changer.
As I understand it, they are using 300-series stainless steel instead of carbon composites. Which relates to some novel techniques in manufacturing parts from stainless [1]. But they don't have a lighter stainless steel, which mostly doesn't make much sense because any steel is basically iron in terms of weight--plus or minus depending upon the additives. Some steels are lighter or heavier than others but within a re…
They are supposedly developing a new stainless steel alloy. I've seen indications it will reduce weight on starship. If its stronger, you can use less of it which is effectively lighter. But I haven't seen real info on what they've developed yet.
Re: XB-1's wings are officially closed out
#86Earlier quoted context omitted.
Not in this case. With SpaceX they also need high (de-entry, Mach heating) and low temperature (cryo fuel & oxygen) resistance but in the case of Boom the surface won’t heat enough to need high temp materials. That said, I’m not sure their choice of materials is the good one for a startup.
CF prices have come down rapidly in the past 20 years and it's becoming the standard structural material for original airframes. It's more workable and less exotic than it was before. I think most, if not all, aviation startups are using it, like the Icon A5.
> CF prices have come down rapidly in the past 20 years and it's becoming the standard structural material for original airframes.
No and no.
CF can mean anything, but typically you end up with structural members that are heavier than aluminum when all is said and done.
Also, CF is used for sub-subsonic (actually sub-transsonic) skins, which SpaceX found out the hard way.
> It's more workable and less exotic than it was before.
No.
> I think most, if not all, aviation startups are using it, like the Icon A5.
Composites are used for subsonic planes and interiors. And the Icon A5 is a toy.
The one good thing about composite (as in the Diamond Aircraft models) is that it's hail resistant up to a certain diameter and intensity, around 1 inch. That has been helpful with some storms in Florida, for example.
Re: XB-1's wings are officially closed out
#87Earlier quoted context omitted.
I hate points like this. Pretty much all technology starts out for rich people. I mean if you don't have supersonic flight at all its technology will not improve either, neither will the economics of scale. Air travel itself is already only for the rich, and travel in general is mostly for the rich, if you want to look at it from the poorest in the world. Elon made this point the best with Tesla, and in 10-20 years t…
They are though. Tesla is a horrible example, electric cars have better fuel economy, so should have a lower TCO for daily users in the long run. Which has always explicitly been Tesla's goal in the long run. This plane, while awesome, is not a Tesla, it's never going to be as cheap as a commercial flight, and it's certainly not going to make the world a better place.
Fuel cost is far from being the dominating factor in TCO; that would be depreciation. I just ran Edmunds TCO calculator on an Audi A6: 5 year TCO of $70k, with depreciation over 5 years being $35k and fuel only contributing $9k.
Electric cars are nowhere near an affordable means of transportation right now (that would be a Hyundai Accent), so GP point stands true.
Re: XB-1's wings are officially closed out
#88Man I'd be sweating like a pig if I was direct-applying epoxy to a prototype so close to done. I'm used to code where trial and error is de rigueur, I forget sometimes you only get one chance.
The biggest change in switching from software to woodworking is that when you cock things up in woodworking, you can't git reset your problems away. The closer I get to done, the more careful I get. Scrapping a part at the beginning sucks, but it's mostly a material cost at that point. As you close in on done, the time dominates the cost, and you get real careful when you have a lot of that in.
Re: XB-1's wings are officially closed out
#89I'm surprised by the assembly tolerances. .05-.1" The F-35 is assembled to .003" The usage of control cables and pulleys is odd. I would have expected hydraulic/electric actuation in a Mach 2+ aircraft.
The F-35 is also low-observable. I'm a total lay-person on this one, but I'm betting that the tolerances for achieving flight (even at Mach 2.2) are a lot looser than the tolerances for being invisible.
Re: XB-1's wings are officially closed out
#90I like the idea of supersonic passenger jets existing again. I'm not sure I really see the point though. Would you rather fly in business class comfort for 8 hours or with less comfort for 4 hours? Almost doesn't seem worth the expense and risk of going supersonic. I would be so much more excited about an airplane that was large enough that economy class seating was as comfortable as business class seating is today.…
>I would be so much more excited about an airplane that was large enough that economy class seating was as comfortable as business class seating is today.
there is really no point where it becomes worth it to make seats bigger without charging more. If there is more space on the plane, it makes more since to put more seats there, not keep the number of seats the same