MODERN AVIATION

Evening Post, Volume CVIII, Issue 133, 2 December 1929, Page 9

MODERN AVIATION

HIGH FLYING RECORDS

SPECIAL 'PLANES NEEDED

(By Prank J. Carmody.) (Copyright.)

High-flying records figure largely in the aviation news of to-day. Commercial pilots are flying stock 'planes upward in an effort to establish some particular variety of "ceiling." B.A.F. flyers are trying to get as far out into space as they can. Flying with and without loads to new heights in light and heavy 'planes, military and commercial, in thoso intended for both land and sea travel seems to bo going on constantly.

It is a very special typo of 'plane that sets the record for really high flying. Its special features 'involve super-charging and special heating devices for the engine, elaborate and delicute instruments for the measurement of altitude, and special devices to protect the pilot from cruelly low temperatures and rarified atmosphere. These 'planes are designed to go out into apace for eight, miles or more. Obviously, tho .'commercial 'plane carrying passengers or mail has no such objective, and "therefore requires no such equipment.

As compared with the special altitude 'pjane, the commercial machine at its best will fly no more than half as high, even if forced to the utmost. That, of course, is as it should to. "Where ; the former will create a record in the vicinity of 40,000 feet, the latter averages in the neighbourhood of 15,000 feet, the range for various types being between 10,000 and 20,000 feet.

An aeroplane, regardless of size, climbs upon its reserve of power; in other words, it ascends on that part of the.engine's energy that is left over from horizontal flight. As a 'plane ascends higher and higher, the engine's power declines and tho reserve grows constantly smaller. Climbing consequently becomes more and more retarded until an absolute limit is reached. This is the key to the explanation of commercial aircraft's more limited altitude.

These machines are intended to carry loads. They are designed to sell at the lowest possible prices and operate with the greatest of economy. The natural result,is that they are not powered beyond the needs of safety and performance at reasonable altitudes. Of course, if one takes one of the lower priced ■'planes, say, and supplants its stock engine with one of higher power, altitude performance as well as other forms will !bo bettered.

It is interesting that the higher powers to which the large air transport 'planes are going in the interest of greater speed—the 'plane's big selling point as a transport medium—are putting them at the top of the eommer«ial machine's altitude list. Take the; largest of air liners, which will carry 20 passengers at a speed of 150 miles an. hour. It has a "ceiling," according to the manufacturer's specifications, pf 17,400 feet.

The. 14-passenger airship of another prominent make will ascen.l to 14,000 feet, while the 10-passenger, 150-mile-an-hour craft that is employed on many transport lines will ascend to 18,000 feet if necessary.

The smaller cabin 'pianos, singleinotored products, have a considerable range in high-flying from 12,000 to 20,000. fectj; according to figures compiled by their designers. The 20,000 feet incidentally represents the maximum among present commercial 'planes. Among the_ hydroplanes the altitude figures are surprisingly high. The lowest powered among.them has a limit of 12,000 feet; the largest and highest powered 19,400; •"-Perhaps -.the most ■widely used machine of this character has a high-flying record of 15,000 feet. These figures indicate how high these ■■"planes are capable of flying; not the altitudes at which they will be flown.