Friday, 19 February 2010

Windmills


A windmill is a machine which converts the energy of wind to rotational motion by means of adjustable vanes called sails. (pictured right: This Dutch windmill in Amsterdam was built in 1757 and is identified a De 1100 Roe. It is a smock mill of the type called by the Dutch a grondzeiler (ground sailer) since the sails almost reach the ground. The main use is for a grinding mill powered by the wind, reducing a solid or coarse substance into pulp or minute grains, by crushing, grinding, or pressing. Windmills have also provided energy to sawmills, paper mills, hammermills and windpumps for obtaining fresh water from underground or for drainage (especially of land below sea level).

History
The windwheel of Heron at Alexandria marks one of the first known instances of wind powering a machine in history. The first practical windmills were the vertical axle windmills invented in eastern Persia, as recorded by the Persian geographer Estakhri in the 9th century. The authenticity of an earlier anecdote of a windmill involving the second caliph Umar (AD 634–644) is questioned
on the grounds that it appears in a 10th-century document. Made of six to twelve sails covered in reed matting or cloth material, these windmills were used to grind grain or draw up water, and were quite different from the later European horizontal-axis versions. (Pictured left: The windmills of Campo de Criptana were immortalized in chapter VIII of Don Quixote.)
Some popular treatments of the subject have speculated that the Afghanistan-style vertical-axle mills were used throughout the Caliphate by the ninth century and spread to Europe through Islamic Spain. This has been denied by the specialist of European medieval technology, Lynn White Jr., who points out that there is no evidence (archaeological or documentary) that the Afghanistan-style vertical-axle windmill spread as far west as al-Andalus, and notes that "all Iberian windmills rotated on horizontal axles until towards the middle of the fifteenth century," which is an indication of their European origin (see below).
A similar type of vertical shaft windmill with rectangle blades, used for irrigation, can also be found in 13th-century China (during the Jurchen
Jin Dynasty in the north), introduced by the travels of Yel├╝ Chucai to Tukestan in 1219.

Fixed horizontal-axle windmills
Fixed windmills, oriented to the prevailing wind were extensively used in the Cyclades islands of Greece. The economies of power and transport allowed the use of these 'offshore' mills for grinding grain transported from the mainland and flour returned. A 1/10th share of the flour was paid to the miller in return for his service. This type would mount triangular sails when in operation.
In northwestern Europe, the horizontal-axle or vertical windmill (so called due to the dimension of the movement of its sails) dates from the last quarter of the 12th century in the triangle of northern France, eastern England and Flanders. Lynn White Jr. claims that the first certain reference to the European horizontal-axle windmill is dated to 1185 in Weedly
, Yorkshire. (This predates Joseph Needham's claim that the earliest known reference is from the 1191 chronicle of Jocelin of Brakelond, in which a Dean Herbert of East Anglia supposedly competed with the mills of the abbey of Bury St Edmunds). These earliest mills were used to grind cereals. The evidence at present is that the earliest type was the sunk post mill, so named because of the large upright post on which the mill's main structure (the "body" or "buck") is balanced. By mounting the body this way, the mill is able to rotate to face the wind direction; an essential requirement for windmills to operate economically in North-Western Europe, where wind directions are variable. (Pictured right: An eight sailed windmill at Heckington, Lincolnshire UK) By the end of the thirteenth century the masonry tower mill, on which only the timber cap rotated rather than the whole body of the mill, had been introduced. In the Netherlands these stone tower like mills are called "round or eight-sided stone stage mills, ground-sailers (windmills with sails reaching almost down to the ground), mound mills, etc." (Dutch: ronde/achtkante stenen stelling molens, grond-zeilers, beltmolens, etc.). Dutch tower mills ("torenmolens") are always cylindrical (such as atop castle or city wall towers). Because only the cap of the tower mill needed to be turned the main structure could be made much taller, allowing the sails to be made longer, which enabled them to provide useful work even in low winds. Such mills often have a small auxiliary set of sails called a fantail at the rear of the cap and at right angles to the sails; this rotates the cap through gearing so the sails face into the wind.

Multi-sailed windmills
The majority of windmills had four sails. An increase in the number of sails meant that an increase in p
ower could be obtained, at the expense of an increase in the weight of the sail assembly. The earliest record of a multi-sailed mill in the United Kingdom was the five sail Flint Mill, Leeds, mentioned in a report by John Smeaton in 1774. Multi-sailed windmills were said to run smoother than four sail windmills. In Lincolnshire, more multi-sailed windmills were found than anywhere else in the United Kingdom. There were five, six and eight sail windmills. (Pictured left: Windmill at the National Ranching Heritage Center in Lubbock, Texas.)
If a four sail windmill suffers a damaged sail, the one opposite can be removed and the mill will work with two sails, generating about 60% of the power that it would with all four sails. A six sail mill can run with two, three, four or six sails. An eight sail mill can run with two, four, six or eight sails, thus allowing a number of options if an accident occurs. A five sail mill can only run with all five sails. If one is damaged then the mill is stopped until it is replaced. Apart from the UK, multi-sail mills were built in Malta and the USA.

Today's Smile

Not so easy then!

The Flying Scotsman


The LNER Class A3 Pacific locomotive no. 4472 "Flying Scotsman" (originally no. 1472) was built in 1923 for the London and North Eastern Railway (LNER) at Doncaster Works to a design of H.N. Gresley. It was employed on long-distance express trains on the LNER and its successors, British Railways Eastern and North-Eastern Regions, notably the 10am London to Edinburgh Flying Scotsman service after which this locomotive was named. In its career 4472 "Flying Scotsman" has travelled 2,000,000 miles (3,200,000 km).

History
The locomotive was completed in 1923, construction having been started under the auspices of the Great Northern Railway. It was built as an A1, initially carrying the number 1472.
"Flying Scotsman" was something of a flagship locomotive for the LNER. It represented the company at the British Empire Exhibition at Wembley in 1924 and 1925. At this time it acquired its name and the new number of 4472. From then on it was commonly used for promotional purposes.
With suitably modified valve gear, this locomotive was one of five Gresley Pacifics selected to haul the prestigious non-stop Flying Scotsman train service from London to Edinburgh, hauling the inaugural train on 1 May 1928. For this the locomotives ran with a new version of the large eight-wheel tender which held 9 tons of coal. This and the usual facility for water replenishment from the water trough system enabled them to travel the 392 miles (631 km) from London to Edinburgh in eight hours non-stop. The tender included a corridor connection and tunnel through the water tank giving access to the locomotive cab from the train in order to allow replacement of the driver and fireman without stopping the train. The following year the locomotive appeared in the film The Flying Scotsman. On 30 November 1934, running a light test train, 4472 became the first steam locomotive to be officially recorded at 100 mph (160.9 km/h) and earned a place in the Land speed record for railed vehicles; the publicity-conscious LNER made much of the fact.
On 22 August 1928, there appeared an improved version of this Pacific type classified A3; older A1 locomotives were later rebuilt to conform. On 25 April 1945, A1 class locomotives not yet rebuilt were reclassified A10 in order to make way for newer Thompson and Peppercorn Pacifics. This included "Flying Scotsman", which emerged from Doncaster works on 4 January 1947, as an A3 having received a boiler with a long "banjo" dome of the type it carries today. By this time it had become no. 103 in Edward Thompson's comprehensive renumbering scheme for the LNER, then 60103 from 1 January 1948, on the nationalisation of the railways when all the LNER locomotive numbers were prefixed with 60.
Between 5 June 1950, and 4 July 1954, and between 26 December 1954, and 1 September 1957, under British Railways ownership, it was allocated to Leicester Central shed on the Great Central, running Nottingham Victoria to London Marylebone services via Leicester Central, and hauled one of the last services on that line before its closure.
All A3 Pacifics were subsequently fitted with a double Kylchap chimney to improve performance and economy. This caused soft exhaust and smoke drift that tended to obscure the driver's forward vision; the remedy was found in the German-type smoke deflectors fitted from 1960, which somewhat changed the locomotives' appearance but successfully solved the problem.
Preservation
Number 60103 ended service with British Railways in 1963 and was sold for preservation to Alan Pegler who had it restored as closely as possible to its original LNER condition. It then worked a number of rail tours, including a non-stop London–Edinburgh run in 1968 – the year steam traction officially ended on BR. As watering facilities for locomotives had by then disappeared a second 8-wheel tender was adapted as an auxiliary water tank.
In 1969 it went on a promotional tour to the USA, where it was fitted with cowcatcher, high-intensity headlamp, bell, air brakes and buckeye couplings. The trip was initially a success, but when Pegler's backers withdrew their support he began to lose money and was finally bankrupted in 1972. Fears then arose for the engine's future, the speculation
being that it could take up permanent residence in America or even be cut up. Fortunately in January 1973 William McAlpine stepped in at the eleventh hour and had the locomotive repatriated and repaired.
In October 1988 the locomotive arrived in Australia to take part in that country's bicentenary celebrations and during the course of the next year it travelled more than 45,000 kilometres (28,000 mi) over Australian rails, including a transcontinental run from Sydney to Perth. It was a central attraction in the Aus Steam '88 festival, double heading with NSWGR locomotive 3801, and running alongside Victorian Railways R
class locomotives along the 300 km (190 mi)-long parallel broad and standard gauge tracks of the North East railway line, Victoria. The "Flying Scotsman" stayed in Victoria for 2 months before heading back to New South Wales. On 8 August 1989 "Flying Scotsman" set another record, travelling 442 miles (711 km) from Parkes to Broken Hill non-stop, the longest such run by a steam locomotive ever recorded.
In recent years "Flying Scotsman" has continued to have an eventful existence. In 1995 it was in pieces at Southall depot in West London and facing an uncertain future owing to the cost of restoration and refurbishment necessary to meet the stringent engineering standards required for main line operation. Salvation came in 1996 when Dr Tony Marchington bought the locomotive and had it restored to running condition at a cost of some £750,000.
In 2004 "Flying Scotsman" was put up for sale because of the mounting debts of its owning company. After a high-profile campaign it was bought in April 2004 by the National Railway Museum in York and it is now part of the National Collection. In 2007 "Flying Scotsman" entered the Museum's workshops for a major overhaul to mainline running standard; planned to be completed by mid 2010 if sufficient funds were raised. The bay in which the locomotive was being refurbished was on view to visitors to the NRM but the engine was rapidly dismantled to such an extent that the running plate was the only component recognisable to the casual observer.

Debate over Restoration
Choice of livery is an emotive subject amongst some of those involved in the preservation of historic rolling stock, and "Flying Scotsman" has attracted more than its fair share as a result of 40 years continuous service, during which the locomotive underwent several changes to its livery.
Alan Pegler's preferred option was evidently to return the locomotive as far as possible to the general appearance and distinctive colour it carried at the height of its fame in the 1930s. A later option was to re-install the double Kylchap chimney and German smoke deflectors that it carried at the end of its career in the 1960s, which encouraged more complete combustion, a factor in dealing with smoke pollution and fires caused by spark throwing.
More recently, until its current overhaul, it was running in a hybrid form, retaining the modernised exhaust arrangements while carrying the LNER 'Apple Green' livery of the 1930s. Some believe that the more famous LNER colour scheme should remain, while others take the view that, to be authentic, only BR livery should be used when the loco is carrying these later additions. The subject is further complicated by the fact that, while in BR livery, the locomotive never ran with its corridor tender.
Early in 2009 it emerged that the spare boiler, acquired following the locomotive's preservation, had been sold.



Getting Your Message Across

There's nothing like a woman scorned!
(Click on image to enlarge)

Computer Definitions

Browser
A problem moose in the garden or blueberry patch.

Network
Mending holes in the fishnets.

Internet
Complicated fishnets repair.

Netscape
What haddock do when you don't do your network

Online
Good sign there'll be clean clothes this week.

Offline
The clothes pegs didn't hold.

Backup
What you do when you a run across a skunk in the woods.

Bar Code
Them's the fight'n rules down at the local tavern.

Bug
The reason you give for calling in sick.