Boxed Munro Mark 4A RAF Contact Cup Anemometer
This is a very nice Boxed Munro Mark 4A RAF Contact Cup Anemometer. Ref No. Met 23000. It is a piece of, as new, Meterological Equipment which measures wind speeds up to 100 knots when connected to an output measuring device, eg. chart recorder (not included).
This particular anemometer was sold off from a RAF weather station in the 1990s and is in the pale blue RAF colour way. We are not sure if it was ever used in earnest but the cups in particular are in very good condition. The main body does have some loss of colour, and surface scuffs and scratches.
- Manufactured by RW Munro Ltd, London, UK (high quality manufacturers of measurement instrumentation)
- Type: RAF Mark 4A
- Cup Diameter = 12.7cm/ 5″
- Height = 30.5cm/ 12″
- Axis to Outer Edge of Cup: 22.5cm (8.87″)
- Serial Number: 359/67/71/86
- Met Office Reference No: 23000
- Washers and bolts (as seen in the images) are stored, incorporated, in the top of the main body of the anemometer. You need to remove the them in order to fit the cup section, then refit them and tighten with the special tool provided.
The Mk4 Munro system was one of the most widely deployed anemometers used for wind speed measurements by the UK Meterological (Met) Office until superseded in the 1990s. In operation, the anemometer is usually mounted on a mast (not included) 10 metres above the ground and in conjunction with a wind direction weather vane (not included). Munro sold this as a system (146), as shown in the advert above from the 1970s.
We fully intended to erect the anemometer in our garden but, alas, this is one of many projects that hasn’t quite materialised, so it is with some reluctance that we have now decided to part with it. They are very difficult to find never mind in such good cosmetic condition! It hasn’t been hooked up in the past twenty years, hence I can’t vouch for measurement accuracy.
It would make a great garden feature, even if you don’t connect it to an output device. I like to watch the cups spinning around in the wind! A must have for the meteorologist or anemometer collector in the family!
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Some Trivia For You Taken From The Met. Office Website
Wind speed is normally measured by a cup anemometer consisting of three or four cups, conical or hemispherical in shape, mounted symmetrically about a vertical spindle. The wind blowing into the cups causes the spindle to rotate. In standard instruments the design of the cups is such that the rate of rotation is proportional to the speed of the wind to a sufficiently close approximation.
At intervals of no longer than five years, anemometers are calibrated in a wind tunnel to identify any departures in the relationship between spindle rotation and wind speed specified by the manufacturer. Calibration corrections are applied to the measured wind speed.