* Posts by nmcalba

14 publicly visible posts • joined 15 Mar 2018

British railway system is getting another excuse for delays – solar storms

nmcalba

Re: From the Beeb article

The issue of Black Start and renewables is something that is being addressed.

The 69MW Dersdalloch wind-farm in Scotland has been designed to work as a Black Start source.

From the Scottish Power website :- "The project used ‘grid-forming’ technology called virtual synchronous machines (VSM) to regulate the frequency and voltage of the power from the turbines – essentially forming a stable network island – to keep the electricity system stable and balanced. The technology was then used to integrate that supply with the grid and restore the part of the system that had been blacked out."

Self-driving car computers may be 'as bad' for emissions as datacenters

nmcalba

It will all depend how they get used

Its not just the potential computing power needed for self driving - a lot of that is happening anyway for additional reasons, but how usage affects overall mileage driven will have a big effect on the overall impact.

Many people point out that a personally owned car is very inefficient, and in one respect they are correct - my car is expensive in terms of resources and money to buy, but spends the vast majority of its time sitting idle outside my house or in a car park somewhere - a very inefficient use of an expensive resource.

But in another aspect my car is immensely efficient - virtually every journey it makes is a "useful" journey - taking me where I want, or need, to go. The only exception is once or twice a year when it has to make a short journey to a garage for new tyres or servicing - maybe 20 miles p.a. out of 20 thousand - that's 99.9% efficient.

One of the big arguments for self driving cars is replacing the personal ownership aspect with a more "efficient" shared style which makes better use of an expensive resource. But its worth noting that almost any form of shared usage, a traditional taxi, Uber, shared ownership whether traditional or driverless will result in a big increase in "useless" journeys - returning to base after dropping a passenger off, going to pick up a passenger, going between jobs. All this means extra mileage, extra fuel consumption (whether of the liquid dinosaur or busy electron variety) and extra road congestion. Now the more widespread the service the lower this useless journey overhead is, but it's never going to approach the 0.1% of the traditional ownership model.

Another aspect is if you have a personally owned vehicle capable of full service driving - how do you use it?. Obviously there are the standard usages - get work done during your commute to work, getting brought home legless from the pub. But there are other possibilities :- Don't want to pay more for your airport parking than the cost of your flight? - just send the car home again after dropping you off and then it can pick you up again on your return. Don't have parking handy near your city centre office or the restaurant you are going to - just send the car home - or maybe send it to find a free parking space out in the residential suburbs (very popular with the residents I'm sure). But this is all additional mileage, additional energy, additional congestion.

One other interesting question - how fast does a driverless car go when it's not in a hurry? - When I am driving or being driven I want to go as quickly as is commensurate with my comfort, safety and maintenance of my driving license - but if I'm say sending the car home after dropping me off somewhere I don't care if it takes 1 hour or 2 - whichever is cheaper in energy terms. We all know that 56 mph is a more fuel economic cruising speed on an motorway that 70 mph - how much better is 30mph? - that's going to cause fun!.

Elon Musk to abused Twitter users: Your tormentors are coming back

nmcalba

Very old proverb

The “vox populi, vox dei” proverb is much older than Machiavelli, it can be traced back at least to the 8th century.

The Archbishop of Canterbury used it in a sermon preaching against King Edward II, and the Jacobites used it in the 18th century.

Over that time it has been used in both positive and negative contexts, and it’s probable that the negative spin that Machiavelli put on it, he actually copied from a Yorkshire clergyman 700 years earlier.

TSMC and China: Mutually assured destruction now measured in nanometers, not megatons

nmcalba

EF50 & British Radar

A couple of issues regarding the Phillips section of the story. I don't believe it was the Chain Home radar system that the EF50 was needed for.

Instead it was the development of the early airborne radar systems for night fighters that required the EF50. You can't put a 60m antenna on an aircraft so the move to a much smaller physical size for airborne radar needed a frequency of around 200Mhz (Chain Home worked on 20-50 Mhz). It was also then used on the later AMES Type 2 radar that filled in the gaps between the main Chain Home stations and the subsequent GCI radar systems that largely replaced Chain Home.

Also the board of Phillips was evacuated (along with a big bag of diamonds) on board HMS Windsor, which was an 1100t W Class destroyer - definitely not a battleship. The consignment of 25,000 completed EF50 tubes along with components and toolling equipment travelled more prosaically on a cross channel ferry.

United, Mesa airlines order 200 electric 19-seater planes for short-hop flights

nmcalba

Re: Why 19?

The 19 passenger limit is potentially much more than just not needed cabin crew.

If you stick to 19 passengers max and keep the maximum take off weight under a certain amount then the aircraft can (in the USA - ESA rules differ) be certified under FAR part 23 rather than the usual part 25 rules that apply to larger airliners

That has a whole host of implications, just a few of which are :-

Not needing cabin crew

Can potentially be operated single pilot

Lower G ratings for structural strength

Lower safety margins for runway lengths

Lower engine out performance requirements

Global tat supply line clogged as Suez Canal authorities come to aid of wedged 18-brontosaurus container ship

nmcalba

Re: 6 million missing badgers

Edit

She's probably fairly heavily laden since she had declared her draught via AIS (Automatic Identification System) at 0.714 Brontosaurus (15.7m) which is only a couple of linguine less than her draught at max load.

nmcalba

6 million missing badgers

This ship could actually weigh over 29 million badgers - the figures quoted on most news sites tend to be the Gross Tonnage which is of course really a volumetric measurement - sort of.

The maximum actual weight of the ship will be a sum of the empty displacement - about 55,000 tonnes - and the Deadweight Tonnage (weight of cargo, fuel, ballast etc) - which can be just over 199,000 tonnes - so the whole lot could weigh in at just over quarter of a million tonnes - or 29 million adult badgers.

How heavily laden it actually is - who knows - the pictures of the bow do show the Plimsoll line quite well out of the water - suggesting a less than full load - but the bow is rammed into the bank so is a bit "up in the air" - other pictures show quite a bow high angle.

I'm sure they are going to have fun getting it moved - the bow is well into the bank - and remember there is also the long underwater bulbous bow that isn't really visible - but must be even more deeply embedded - this ship is pretty much the maximum size that is allowed through the Suez canal.

Australia down for scheduled maintenance: No talking to Voyager 2 for 11 months

nmcalba

The Deep Space network

An interesting site that I often like to have a glance at is https://eyes.nasa.gov/dsn/dsn.html

You can see what part of the deep space network is talking to what satellite/probe - and the data rate etc.

Tesla Autopilot crash driver may have been eating a bagel at the time, was lucky not to get schmeared on road

nmcalba

It will be interesting when the 1st similar case happens in the UK what the police reaction is

I find it interesting that in none of these incidents is there much mention of the driver being charged with anything.

I don't know details of US traffic laws, but I'm 99% certain that if such incident happened where I live and the driver gave that sort of account the next words out of the police officers mouth would involve the phrase "You will be reported to the Procurator Fiscal for consideration of prosecution for offences under the Road Traffic Act".

The interesting thing is whether the charge would be "Driving without due care and attention" - a traffic offence carrying fine and possible license suspension or the more serious "Dangerous Driving" which is a criminal matter quite a few of the aspects mentioned would be likely to jump it up to the more serious charge.

Quite apart from the issues round Autopilot the police attitude here is that there is no genuine reason to run into the back of another vehicle, you were either driving too close, too fast, not paying attention, not driving to the road conditions or had defective brakes/tyres - and its almost automatic for people to be charged, unless they have a really exceptional excuse.

Microsoft cofounder Paul Allen's personal MiG-29 fighter jet goes under the hammer

nmcalba

Re: Its OK as long as you keep the noise down

The language in FARs about "reaching the surface" I beleive is more to do with the issue of going supersonic in coastal areas - you have to be far enough offshore that the sonic boom doesn't reach land - for Concorde the sonic boom track was up to 100km wide.

nmcalba

Its OK as long as you keep the noise down

I believe you can own a supersonic aircraft as long as you are quiet about it.

There are a couple of sections in the FAR (Federal Aviation Regulations) about them - FAR91.821 for example - that are mainly concerned with noise limits - essentially they must meet stage 2 noise limits for take off and landing and you cannot operate it above Mach 1 unless you can show that the sonic boom will not reach the surface.

First Boeing 777 (aged 24) makes its last flight – to a museum

nmcalba

50k hours vs 20k cycles

With regard to the low number of hours per flight (2.5ish) for a long haul aircraft.

The likely reason is that it spent a lot of its time on the Taiwan run - 1h55.

Cathay Pacific has almost 20 flights a day from HKG-TPE - all of them large wide bodies (A330s and 777s). It is one of the busiest international routes in the world.

Cathay also has quite a lot of other short/mid-haul routes it uses large wide bodies on - Seoul, Manila etc.

Boeing ships its 10,000th 737

nmcalba

Re: A milestone, surely

Well according to the air fleets database :-

869 out of 3132 737s (original and classic) are still active i.e. not scrapped, stored or written off.

and for the 737 NG, 6556 out of 6787 are active.

That gives a total of 7425 out of 9919, this I know is not 10,000 but I suspect that the difference is accounted for by frames that have come off the assembly line but are not yet registered and flying.

For the A320 you have to take the entire 320 family:-

A318 - 58 out of 80

A319 - 1366 out of 1469

A320 - 4241 out of 4835

A321 - 1554 out of 1657

This gives a total of 7219 active aircraft - so although the 737 is ahead its only by a very short nose.