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Drones at Gatwick, and elswhere, ongoing.
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boisdevie



Joined: 26 Dec 2012
Posts: 299
Location: N Lancashire

PostPosted: Thu Dec 20, 2018 2:14 pm    Post subject: Drones at Gatwick, and elswhere, ongoing. Reply with quote

Oh how easy it is to shut down a major airport with minimal investment/risk. Just a perfect example of what a precarious system we live in.
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adam2
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Joined: 02 Jul 2007
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PostPosted: Thu Dec 20, 2018 2:58 pm    Post subject: Reply with quote

I smell a rat and suspect that there is more to this than is immediately apparent.

1) Is it some new form of holy jihad, perhaps with drones that can carry small explosives, or are to be steered into aircraft engines.


2) Is it some form of local protest against airport expansion.

3) Or perhaps some form of deep green action to disrupt and thereby discourage air transport. If such action is repeated it could cause enough disruption to deter some people from flying, and also cause enough expense to discourage investment in aviation.

4) Or perhaps a grudge by a former employee, looking to cause disruption.

If it IS any of the above, it has proved highly effective, which will encourage more of the same.
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adam2
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PostPosted: Thu Dec 20, 2018 3:13 pm    Post subject: Reply with quote

Sussex police now state that this is "NOT terror related but IS a deliberate act of disruption"
They also state that the drones are of "industrial specification" which to me implies the relatively large drones used for various purposes.
Two of those, one into each engine, could probably bring down an airliner.
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Little John



Joined: 08 Mar 2008
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PostPosted: Thu Dec 20, 2018 4:39 pm    Post subject: Reply with quote

It's a lone remainer sat in his or her allotment with a remote control , determined to show us all how f***ed we will be when the EU puts us on the naughty step.
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adam2
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PostPosted: Thu Dec 20, 2018 6:27 pm    Post subject: Reply with quote

The army have now been deployed with "specialist equipment"

An earlier suggestion that armed police should shoot down the drones was rejected due to the risks from stray bullets.

Presumably something more sophisticated than the hand guns and rifles that armed police use is to be deployed.
(Armed police DO have access to shotguns, and these can bring down a drone, but only at short ranges.)
Some short of explosive shell that bursts a short and known time after being fired is called for. As used to bring down full sized aircraft. These munitions have two great advantages over rifle and machine gun rounds.
Firstly a near miss should kill the drone as the shell bursts and scatters shrapnel, whereas a rifle bullet must score a direct hit on a very small and moving target.
Secondly after the shell bursts, the debris falls into a relatively small area, whereas a rifle bullet fired towards a drone could be dangerous a least a mile away and perhaps at two miles.
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Lurkalot



Joined: 08 Mar 2014
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PostPosted: Fri Dec 21, 2018 10:05 am    Post subject: Reply with quote

Looking at it from an envoiromental point of view and using google as as rough basis for figures an average airliner will use around 30,000 gallons of fuel in an average flight . 1 gallon burnt will produce 21LBs of CO2 which gives 630,000LBs per flight , thus the 760 scheduled flights on the one day will produce 478,800,000 LBs or 213,750 tons of CO2 . Granted not all flights were cancelled some were diverted and some people ferried in coaches but that is still a very good return , so to speak , a couple of drones have probably or potentially saved up to a six figure amount off CO2 being released.
And if the intent was commercial rather than envoiromental then the losses must run into the millions I would have thought.
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adam2
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PostPosted: Fri Dec 21, 2018 11:33 am    Post subject: Reply with quote

Yes, the reduction in carbon dioxide emissions is indeed most welcome, and there might even be some longer term reductions if some future air travel is deterred by this incident.

Except in the most extreme of circumstances, I would prefer legal and constitutional means of reducing carbon emissions rather than this, or other, illegal tactics.

Whoever did this is probably pleased with the results, and I expect more such incidents.
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vtsnowedin



Joined: 07 Jan 2011
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PostPosted: Fri Dec 21, 2018 12:53 pm    Post subject: Reply with quote

Lurkalot wrote:
Looking at it from an envoiromental point of view and using google as as rough basis for figures an average airliner will use around 30,000 gallons of fuel in an average flight . 1 gallon burnt will produce 21LBs of CO2 which gives 630,000LBs per flight , thus the 760 scheduled flights on the one day will produce 478,800,000 LBs or 213,750 tons of CO2 . Granted not all flights were cancelled some were diverted and some people ferried in coaches but that is still a very good return , so to speak , a couple of drones have probably or potentially saved up to a six figure amount off CO2 being released.
And if the intent was commercial rather than envoiromental then the losses must run into the millions I would have thought.

You have confused gallons with pounds so your figures are off by about a factor of eight.
Quote:
The 737-800 is also among the models replacing the McDonnell Douglas MD-80 series aircraft in airline service; it burns 850 US gallons (3,200 L) of jet fuel per hour, or about 80 percent of the fuel needed by an MD-80 on a comparable flight, even while carrying more passengers than the latter.[30] According to the Airline Monitor, an industry publication, a 737-800 burns 4.88 US gallons (18.5 L) of fuel per seat per hour.[31]Alaska Airlines replaced the MD-80 with the 737-800, saving $2,000 per flight, assuming jet fuel prices of $4 per gallon. The fuel cost of each such flight (2008 prices) on a 737-800 is about $8,500.00."

So the plane needs ten gallons or so for each passenger to move 1000 miles where four in a car getting 35mpg would use 7.14 per passenger.
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adam2
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PostPosted: Fri Dec 21, 2018 1:08 pm    Post subject: Reply with quote

Gatwick now reopened, though disruption is expected for several days due to the backlog of passengers and the numbers of crews and aircraft that are displaced.

As regards fuel consumption, airliners and cars have broadly similar fuel consumption, per mile, per passenger.
No great accuracy can be claimed for this statement since both cars and aircraft vary a great deal.
Short haul air tends to use more fuel per mile, but long haul uses more in total.
The environmental cost of air travel comes largely from the speed thereof encouraging longer distance travel.
Very few people would drive 1,000 miles for a weekend break, yet flying 1000 miles or more is routine.
Most people drive to/from airports resulting in significant car miles in addition to the flight.
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stumuz1



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PostPosted: Fri Dec 21, 2018 1:16 pm    Post subject: Reply with quote

I think you are nearer to the figure VT.

I have mulled this over for a few years now, it was debated at length sometime ago on this forum.

My reasoning is thus; I ,like the swallows, fly south for the winter!

I have worked out that i use approx 55 litres of aircraft fuel to fly to the Canaries for Jan/Feb. Canaries being about 2000 kms away.

Now if i stayed at home for Jan/Feb (the most fuel intensive months of the year) I would get through five tons of wood plus gas and electric.

At first blush moving to the sunshine for two months is a sensible thing to do and massively cuts down on carbon emissions.

Plus a future saving of better health (no colds, flu) healthier lifestyle (more swimming, beach volley ball) will save the NHS a packet in the future.

Any contrary opinions?


Last edited by stumuz1 on Fri Dec 21, 2018 1:19 pm; edited 1 time in total
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stumuz1



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PostPosted: Fri Dec 21, 2018 1:18 pm    Post subject: Reply with quote

For info

https://en.wikipedia.org/wiki/Fuel_economy_in_aircraft
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vtsnowedin



Joined: 07 Jan 2011
Posts: 5272
Location: New England ,Chelsea Vermont

PostPosted: Fri Dec 21, 2018 1:23 pm    Post subject: Reply with quote

Well four in a car getting 35mpg is a best case scenario. I can't think of four people I want to spend seventeen hours cramped inside a small economy car with. Rolling Eyes My own truck with just me in it is much less efficient especially when you add in the food and motel bill a 1000 mile trip would entail.
The point being that air travel is efficient in both time and fuel requirements for those that truly need to travel.
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Lurkalot



Joined: 08 Mar 2014
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PostPosted: Fri Dec 21, 2018 1:41 pm    Post subject: Reply with quote

vtsnowedin wrote:
Lurkalot wrote:
Looking at it from an envoiromental point of view and using google as as rough basis for figures an average airliner will use around 30,000 gallons of fuel in an average flight . 1 gallon burnt will produce 21LBs of CO2 which gives 630,000LBs per flight , thus the 760 scheduled flights on the one day will produce 478,800,000 LBs or 213,750 tons of CO2 . Granted not all flights were cancelled some were diverted and some people ferried in coaches but that is still a very good return , so to speak , a couple of drones have probably or potentially saved up to a six figure amount off CO2 being released.
And if the intent was commercial rather than envoiromental then the losses must run into the millions I would have thought.

You have confused gallons with pounds so your figures are off by about a factor of eight.
.


Google is a bit haphazard at times I will admit and depending on how one frames the question it gives results between 18.6 and 21 lbs of co2 produced per gallon although it's less clear whether it is working with imperial or US gallons. I perhaps should have stuck with litres. It also gives figures of 36,000 gallons used by a 747 on a 10 hour flight which is why I chose 30,000 gallons as a very rough approximation .
Figures per passenger mile or gallons per passenger are I think a little skewed and if a plane isn't full it will give worse figures than one with every seat filled.
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vtsnowedin



Joined: 07 Jan 2011
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PostPosted: Fri Dec 21, 2018 2:57 pm    Post subject: Reply with quote

Lurkalot wrote:
vtsnowedin wrote:
Lurkalot wrote:
Looking at it from an envoiromental point of view and using google as as rough basis for figures an average airliner will use around 30,000 gallons of fuel in an average flight . 1 gallon burnt will produce 21LBs of CO2 which gives 630,000LBs per flight , thus the 760 scheduled flights on the one day will produce 478,800,000 LBs or 213,750 tons of CO2 . Granted not all flights were cancelled some were diverted and some people ferried in coaches but that is still a very good return , so to speak , a couple of drones have probably or potentially saved up to a six figure amount off CO2 being released.
And if the intent was commercial rather than envoiromental then the losses must run into the millions I would have thought.

You have confused gallons with pounds so your figures are off by about a factor of eight.
.


Google is a bit haphazard at times I will admit and depending on how one frames the question it gives results between 18.6 and 21 lbs of co2 produced per gallon although it's less clear whether it is working with imperial or US gallons. I perhaps should have stuck with litres. It also gives figures of 36,000 gallons used by a 747 on a 10 hour flight which is why I chose 30,000 gallons as a very rough approximation .
Figures per passenger mile or gallons per passenger are I think a little skewed and if a plane isn't full it will give worse figures than one with every seat filled.
OK I was thinking average air liner and the 747 is top of the line not average. They indeed burn 36,000 gallons in a ten hour flight while carrying an average of 452 passengers. (Full load 525+/- depending on version). That still works out to 63 passenger miles per gallon and gets you there at 500+ nautical miles per hour. Very efficient in my book CO2 not withstanding as all alternatives would produce more including staying at home.
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Lurkalot



Joined: 08 Mar 2014
Posts: 242

PostPosted: Fri Dec 21, 2018 6:34 pm    Post subject: Reply with quote

vtsnowedin wrote:

The point being that air travel is efficient in both time and fuel requirements for those that truly need to travel.


I wouldn't argue against the stance that it's efficient in both time and relative fuel consumption against a car especially if one adds in the energy used in the infrastructure of roads , bridges , ferries and so on. I perhaps should have put another very in te very rough estimate bit.
There might be an argument about just how many of the 100,000 people affected feel they truly need to travel but I'd put money on it being the majority who would argue their journey was necessary.
As I was typing this my wife has jut read that te drones are back .
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