Chocks away and a first for flight
QUESTION Which was the first aircraft with a practical retractable undercarriage?
INNOVATIVE aircraft design i n the Twenties and Thirties was based primarily on reducing aerodynamic drag, and the era saw advances i n many technologies, including structures and materials, wing shapes, streamlining, low- drag engine cowlings, variable pitch propellers — and retractable landing gear.
Technology was driven by the fashion for air races, the greatest of which, such as the Schneider Trophy, fostered competition between international powers, sparking a technological arms race (and famously helping to evolve the Spitfire).
A retractable undercarriage was first incorporated into an aircraft in 1920. The Dayton-Wright RB-1 (rinehart-Bauman One), also known as the Dayton-Wright racer, was designed to participate in the 1920 Gordon Bennett Cup air race. But the mechanism, operated by a hand- crank, wasn’t particularly successful as its weight hampered the plane’s flight speed.
In the 1923 Pulitzer Trophy race at Mitchell Field, long Island, the U.S. Army entered a low-wing monoplane, an advanced version of the Verville Sperry r- 3, incorporating manually operated retractable landing gear. But mechanical problems forced the r-3 to drop out of the race, which was won by a design classic, the Curtiss racer flown by lieutenant Alford J. Williams at the then terrific speed of 245.8 mph, almost 40 mph faster than the winner’s speed a year before.
The r-3 won the Pulitzer race the following year, but at only 215 mph. The 1930 Boeing Monomail integrated several critical new design features, including an all-metal structure, a smooth stressed skin, cantilevered wing, Townend ring cowling and retractable landing gear.
The Monomail was succeeded by a much more successful aeroplane, the lockheed Orion, a low-wing version of the pioneering Vega. This was the first commercial aircraft with an efficient retractable undercarriage. Orions first went into service in May 1931 with Bowen Airlines of Texas.
A hand-crank method of retraction was initially employed, but by the time Orions went into service, a hydraulic hand pump system had been developed.
The Orion had a maximum speed of 226 mph, outperforming any existing commercial model, and was the first aircraft to gain a significant advantage from the technology.
John Miller, Farnborough.
QUESTION Can microscopic creatures see
one another? ALMOST all life on our planet requires sunlight for energy, and because life is so closely linked to the sun, most animals (96 per cent) have evolved the ability to detect and respond to light.
Single- celled algae, protists and other microbes have a basic photosensitive ability that enables them to swim towards or away from light, though these ‘eyes’ are not complex enough to enable them to ‘see’, as we understand it.
A microbe ‘eye’ is able to detect light, sense the direction it is coming from using pigment cells and relay this information to motor structures such as cilia. In some organisms, all three of these functions are carried out by one cell — the single-celled euglena, unicellular flagellate, living in seas and lakes is a known example.
Though their eyes are not used for identification, it does not mean microbes are not able to detect each other.
Single-celled bacteria might appear to be the simplest of organisms, but they are, in
fact, highly sophisticated entities that are able to communicate using chemical signalling molecules called autoinducers.
Similarly all protozoans, single- celled organisms, have chemical or tactile senses to detect other members of their own species for sexual reproduction.
A sensory structure has been identified in ciliates called kineties (found beneath the surface of the cell membrane at the base of each cilia). These are organised in a brush-like formation at the mouth and are used for prey recognition.
Mark Beaumont, Bangor, Caernarfonshire.
QUESTION When, how and why did chiropody
become podiatry?
chiropody became podiatry in 1993 as it is the internationally recognised name for a foot specialist and a more accurate term. Chiropody is derived from the Greek chiro meaning ‘hand’ and pod, the stem of Greek pous for ‘foot’.
Originally, chiropodists treated both hands and feet, but this is no longer the case. Podiatry comes from pod for ‘foot’ and iatreia ‘healing’. It was deliberately created in 1914 to supplant chiropody and distance the practice from the popular impression of unskilled corn-cutters.
Podiatrists usually study on a full-time, three-year degree course. Practitioners are not only able to offer the most obvious treatments for corns, verrucas and hard skin, but specialities exist within the profession for almost any lower limb problem, including biomechanics, postsurgery rehabilitation, orthotic manufacture and sports injury.
÷ Is there a question to which you have always wanted to know the answer? Or do you know the answer to a question raised here? Send your questions and answers to: Charles Legge, Answers To Correspondents, Scottish Daily Mail, 20 Waterloo Street, Glasgow G2 6DB. You can also fax them to 0141 331 4739 or you can e-mail them to charles.legge@dailymail.co.uk. A selection will be published but we are not able to enter into individual correspondence.
WHY Would Anyone Want To Swing A Cat? The latest compendium of the Daily Mail’s celebrated Answers to Correspondents column, packed with facts, information, anecdotes and curiosities, is now available. To order your copy for the special price of £7.99 (RRP£9.99) call 0844 472 4157 or visit mailbookshop.co.uk