powderpig

The only benefit I've really made sense of with hybrids is their engine emissions aren't localised to the neighborhood where they're charged overnight. Apart from that, I can't think of anything else.

You should check out the Artemis I engineering footage.

Red Dragon? Falcon 9 Booster 24-hr turn around? The plethora of missed milestones required to land on the moon's surface?

Metro?

I'm only here for the free U2 album.

"U2's latest album automatically added to your library"

Conventional jet engines run at RPMs in excess of 20000rpm. To get this same speeds for the same mass flown rates of say a J79 (F4-Phantom) you'd be looking at some massive electric motors. Conventional jet engines would be using electric motors if they were light enough already.

There is a reason Rolls-Royce UltraFan uses a speed reducing gearbox for it's fan blades and not an electric motor.

More to the point above, at hypersonic speeds, using a conventional compressor is sort or useless unless you can keep your air cool.

Virgin Orbit anyone?

Maintaining a pressure boundary becomes ever more difficult with increase in size, and therefore cost and engineering complexity.

Roughly how many hours did Euan spend to complete this piece of work?

Ever heard of ITAR? As a European I find the US's reluctance to adhere to EU law double standard.

I highly recommend AccuBattery for Android. I have been using it for a few years now and I saw a noticeable difference on my Pixel 3a XL compared to use on previous smart phones. I now have a Pixel 6 and its nearly 2-years old and the battery lasts well beyond 30-hrs with combined use.

https://play.google.com/store/apps/details?id=com.digibites....

How is China a problem? The way of life and the energy intensity of a single individual living in the developed world is the problem. Do I have to point out the US and Europe? (I live in the UK).

This is essentially the Boots Theory, coined my Terry Pratchett. The reason that the rich were so rich, Vimes reasoned, was because they managed to spend less money. Take boots, for example. ... A man who could afford fifty dollars had a pair of boots that'd still be keeping his feet dry in ten years' time, while a poor man who could only afford cheap boots would have spent a hundred dollars on boots in the same time and would still have wet feet. Men at Arms. p. 32.

When's a good time to stop technology advancement for those of us who are willing to pay for it? There will never be a right time.

There are a number of reasons why it might have failed, fatigue, deviation from process/protocol but pressure vessels are well understood and not the problem here.

The "space" launch was using American technology, nothing about the failure was "British", in my mind. Volt on the other hand...

Worth noting the use of titanium at Mach 3, Mach 3.5, is really at its limit. Any faster and you'll start to see serious problems with thermal management. This pushes you into using super nickel alloys or even ceramic matrix composites, which would be necessary for use cases at Mach 5+ for sustained flight. Acknowledging planes in the last have gone faster like the X-15 but this such plane's architecture wouldn't stop for longhaul flight distances. CMCs and super nickel alloys will be very very expensive.

And I think this is one of the reasons we are seeing so many companies racing to create a commercially viable eVTOL (electric - vertical take-off & landing) product. To me, this transport system only seems to be a solution to the problem mentioned above. I can't see them ever being commercially viable (FAA regulation, power density, etc.) And yet there are a lot of companies trying to make them a reality when really the cities they have renders of with their flashy electric vehicle flying over just need better public transport systems.

Like the Russians?

Is electricity so expensive in some countries that burning fossil fuel for heat is cheaper than using an electrical heat pump?

Yes. I can't remember the exact source but this charity covers it well. Up to 30% of Africa still burns kerosene for light.

https://solar-aid.org/news/black-carbon-and-the-kerosene-lam...

I think all geo-engineering is a bad idea. The least worse idea is sucking CO2 out of the atmosphere.

The consequences of any geo-engineering ideas are not well understood.

I too hate the coloured plots but I can tell you as a Stress & Structures engineer who works with ANSYS regularly, it does help when assessing material limits and strain energies. This is especially true when you're working with models where temperature is time dependent.

A great article, one to bookmark for sure.

I am afraid I don't have the numbers to back up my claim but when I was at university, my thermodynamics lecturer showed us a calculation that background dose from radioactive material at a coal powered fire station is higher than that of a nuclear power station. This is because of the shear amount of coal power stations burn through, and in that fuel, there is a trace amount of radioactive material that eventually gets out into the atmosphere.

I've previously worked on a nuclear licenced site and we were not even allowed to throw smoke alarms in the general rubbish due to there being radioactive material inside.

I'd imagine the most complex engine ever to use the full flow staged combustion cycle has a large price tag.

I can't see this ever being approved for human flight without major seeing changes.

...major design changes.

I cannot believe that Spacex are planning to eventually make Starship human rated and yet there still won't be a launch escape system.

I can't see this ever being approved for human flight without major seeing changes.

Even if the design is fully proved out and works flawlessly, the reliability numbers behind the Raptor engine just aren't there yet.

Lithium-ion fires are hard to extinguish, especially with thermal runaways. There are flame retardant products that can extinguish lithium-ion fires, Class D extinguishers can be used.

I would guess the fire crews that responded were not equipped with this type of extinguisher.

Would you put any of Spacex's launch services in those widely successful projects?

The new chairman has apparently donated to the Tory party.

https://bylinetimes.com/2021/01/06/new-bbc-chairman-richard-...

The DG was also a former deputy chairman of Hammersmith and Fulham Conservative party.

https://inews.co.uk/news/tim-davie-new-bbc-director-general-...

Did you know that the Vulcan's engines were developed into the engines that powered Concorde?