Blimps

by R. G. Picinich, Jr

You've seen these blimps floating iauntily about in the sky. This is the story of their successful operation over more than a score of years.

America, primarily because of the war emergency, is becoming a nation of air-minded individuals. What the government is doing today to interest its citizens in the art of flying, the Goodyear Tire & Rubber Co. has been doing in a lesser degree for the past two decades, quietly and without fanfare — but with worthwhile results.

A fleet of Blimps, stationed at population centers throughout the nation, has introduced 367,683 persons to this pleasant and educational pastime. Passengers have been carried for a distance of 3,724,129 miles without a single fatality, and in setting this record the airships made 137,267 flights.

The company had a three-fold purpose in inaugurating this service — to make Americans air-conscious, train personnel for both civil and war requirements, and to experiment with and improve equipment and materials.

Since this is a story of the Blimp, the non-rigid, lighter-than-air ship, let's start by making clear how it differs from the heavier-than-air plane. The principal difference is in the source of lifting power. The airplane is a dynamic craft, deriving power from its velocity alone, since the air pressure and suction on its wings give aerodynamic lift only as long as flying speed is maintained. The airship is aerostatic, that is, its buoyancy arises from the fact that the lifting gas is so much lighter than air that it will support, without other assistance, not only the balloon in which the gas is contained but the craft itself and the weight of crew, motors, fuel and payload. The airship will remain in the air even though its motors are shut off, a big safety factor.

The non-rigid airship is really a balloon, shaped like a huge cigar to give it directability, and carrying motors to give it forward movement, which maintains its shape by means of the pressure of the gas it contains. The popular name, Blimp, is derived from B-limp type, the British designation during the World War to distinguish "limp" ships from rigid. An interesting feature of the non-rigids is an air-filled balloonet, built inside the cigar-shaped balloon with the result that, as the lifting gas expands, due to temperature or altitude, it forces air out of the balloonet, the gas being conserved. Conversely, as the gas contracts, more air is forced in from the slipstream of the motors or by a blower.

Another essential difference between the airship and the airplane is that blind flying by plane may be hazardous, since control failure or an operating mistake by the pilot may send the airplane into a spin from which it may be unable to recover, whereas the airship is fundamentally stable and may fly through fog with impunity. Blimps can be sent out in weather where it is inadvisable to use airplanes.

Goodyear's lighter-than-air activity began in 1911, when the first specialized machinery for spreading rubber on fabric was installed. Its first Blimp was built in 1919 when a tiny hydrogen bag of 37,000 cu ft, nicknamed the Pony Blimp, was completed. It was based in Los Angeles and demonstrated the possibilities of small aircraft. While the airplane had become by then a common sight, the only lighter-than-air ships were the army and navy ones, rarely seen by the public and then at a distance. The Goodyear Blimps came down out of the sky, mixed with the people of America, and slowly began to stimulate interest in this phase of aviation.

The present Goodyear Fleet began with the launching, in June 1925, of the Pilgrim, a 51,000-cu ft-capacity ship called "America's first air yacht," as the initial non-rigid to be built with a closed cabin. It was flown with the non-inflammable helium gas — as have the others since. In 1928 came the Puritan, a twin-motored cabin ship of 86,000 cu ft. Early in 1929 the Volunteer, Mayflower and Vigilant came out of the shop — then the Defender, 184' long and with a gas capacity of 180,000 cu ft, capable of carrying 10 passengers. The Reliance in 1931 and the Resolute in 1932, both of 112,000 cu ft capacity, were replacement ships to the Vigilant and Mayflower.

In christening the Blimps, President P W Litchfield of Goodyear selected names made famous by American Cup- defending yachts in the international races. Of the eleven ships with the fleet in the fifteen years, the Pilgrim has been in the Smithsonian Institute since 1932; the largest, the Defender, was rebuilt in 1935 for military purposes, and five are still in service — the Volunteer, the Reliance, the Enterprise, the Resolute and the Rainbow. The oldest, the Volunteer, completed ten years of active service on April 27, 1939, and is the only non-rigid to make a transcontinental round trip. Two ships, the Rainbow and the Reliance, are based this summer at Bendix Airport and carry passengers an advertising over New York City, skirting the World's Fair, and in nearby New Jersey. One ship each is stationed in Washington, DC, and Akron. The Blimps are flown in Florida coast resorts during the Winter and have also operated at both the Chicago and Cleveland expositions.

The thousands of persons who have gone aloft have paid from $1 to $5 each. The low-priced ride is of some 5-min duration, one of 30 minutes costs $4 and where six people go up at one time they may cruise for 45 min at $5 each. The flights begin at 11AM and continue until dark and are operated without profit to the Goodyear company. There is a good deal of pleasure in this type of flying and, as the ship floats along at 40 miles an hour, there is no pronounced sense of motion — just a faint roll from side to side, or a slow rise and fall as the craft passes through different air currents. The cabin, or gondola, holds 6 passengers in comfortable, bus-like chairs. In front sits the pilot, in n armchair, with a wheel at his right and for controlling climb or descent. His feet rest on a pair of pedals, for steering. Above the forward window is a row of control knobs that resemble electric fuses and which are used to control the distribution of helium gas, to make the ship more buoyant in the nose or stem as may be necessary to compensate for atmospheric changes. At the pilot's left hand is the throttle for the two engines, suspended on each side of the gondola, while before his eyes there are many instruments including the compass, altimeter, airspeed indicator, fuel gauge, oil presure, etc. From a hook above the window hang a set of radiophones, for each ship is equipped with a two-way radio and maintains ground contact at all times. The dirigible usually cruises at an altitude of 1,500 ft and the panoramic view spread below is ever an awe-inspiring spectacle to the novice.

To get the small ships into the air a ground crew of some fifteen men is needed. When he is ready to rise, the pilot signals and the crew swings on the handrails along the outside of the gondola. They bounce the craft on and off the ground several times, letting it rebound from the powerful spring attached to the landing wheel. After three or four of these bounces the "up" signal is given and each man of the ground crew heaves into the air with his full strength and the dirigible soars aloft.

Non-rigids make no ambitious claims to long-distance flying, although the Naval C-2 flew 2,200 miles from New York to Cape Charles Light and returned in 33 hr and 6 min. The Defender cruised from Akron to Miami with one intermediate stop, 1,240 miles, and smaller Goodyear ships have several times made flights of 500 and 600 miles. The best record in speed perhaps ever made by a Blimp was attained by the Puritan which flew from Akron to Langley Field, VA, covering the 425-mile trip in 5 hr, or better than 80 mph.

These small dirigibles have been more fortunate than most aircraft, meeting most of the hazards of weather in the United States, Canada, Mexico and Cuba — riding through wind, hail, snow and sleet storms and out of the menace of fog, although the company's policy is not to send a ship aloft in bad weather except in an emergency. Only when a Blimp has been damaged enough not to be rebuilt is its name stricken from the rolls. Latest of these was the eleven-year-old Puritan which had carried 95,000 passengers, flown more than 600,000 miles — an unusual record for a non-rigid airship — before being caught in the hurricane that flashed through New England in September, 1938. The airship Vigilant was taken off the list in 1930 when it flew into a mountainside in a dense fog in northern Alabama.

Goodyear built a large airship dock at Wingfoot Lake, near Akron, during the war [WWI —JLM], large enough to accomodate five Blimps at a time. The company erected docks alongside its plants at Gadsden, AL, and Los Angeles, CA, and one at Pal-waukee Airport, Chicago.

Oil-burning Engines

An interesting development in 1931-32 was a diesel-type motor of Packard design, 225 hp, which was successfully installed on the Defender. Oil-burning engines of this type will remove the last item of fire hazard from lighter-than-air craft. The small ships also proved useful in testing the gelatin-latex fabric which had been developed for the gas cells of the USS Akron and Macon, replacing goldbeater skin.

Three forms of advertising by Blimps — neon signs for night flying, advertising streamers for day flights, and powerful loud speakers — have at- tracted wide attention. The neon characters are 6' high by 4'. wide, weigh 650 lb, consist of a maze of glass tubes, and each unit can form any number or any letter of the alphabet. There are ten of these units and they can be attached to the bag of a dirigible in 15 min. While in the air, an automatic mechanism spells out the message, one word at a time, and is operated from a perforated tape, similar to that used in player-pianos, which can be so adjusted that it will repeat the message over and over again. New tape can be prepared while in flight, on a special machine similar to a typewriter, and different messages flashed at will. The streamers used in the daytime consist of characters 8' high and up to 450' long. As the Blimp gets into the air this floating sign is held in horizontal position by the slip-stream from the motors. The loud speakers called "Cloud Speakers," operate effectively up to 1,500 ft and in addition to their advertising uses have aided police in directing traffic at bottle-neck spots. The neon signs and streamers can be read a mile away.

Of the 19 pilots in active duty with the fleet, three have been flying since the World War. Captain J A "Jack" Boettner, Chief of Airship Operations with more than 10,000 hr, is a veteran balloon and airship pilot and is the holder of the first airship pilot's license issued by the US Department of Commerce. He was instructor at Wingfoot Lake during the war, breaking in hundreds of Army and Navy men as pilots of balloons and airships. The average number of hours in the air for Goodyear pilots is in excess of 5,000 and the flight personnel have averaged better than 11 years a licensed pilots, and made 40 Atlantic crossings on dirigibles while in training. Eight are officers in the Naval Reserve and are available for duty with the fleet in an emergency.

The first step in training a lighter-than-air pilot is the free balloon. Each novice must become a licensed balloon pilot before receiving training on air ships — as an airship becomes a free balloon and is handled in exactly the same manner should its engines stop. Balloon training is conducted at the company's Akron base by men with race victories to their credit. In addition to air-training, the student is required to pass ground school course of extreme rigidity and usual courses on engines, navigation, aerodynamics etc, must be supported by aerostatics, chemistry of gases, airship design and maintenance, and fabric construction.

Tasks performed in peacetime by the Blimps include locating of forest fires, photographic and rescue work, spraying for insect control, police scouting and traffic directing, surveys, and map and movie making. During the World War no convoy was attacked when guarded by an airship and in the seventeen months prior to the Armistice, British airships sighted 49 submarines and successfully attacked 27 of them; they convoyed 2,000 surface vessels and carried out over 9,000 anti-submarine patrols — and from Jan 1 to Nov 11, 1918, there were only nine days in which these ships could not fly because of bad weather. Both sides in the present World Conflict are using lighter-than-air craft effectively. Acting as an aerial listening post — for the Blimp can hover over a given spot carrying of infra-red optical range locating apparatus, map-making, photography and related work are among other war activities.

This article was originally published in the October, 1940, issue of Aviation magazine, vol 39, no 10, pp 48-49, 120.
The original article includes 5 photos.
Two photos credited to Rudy Arnold; the rest are probably from Goodyear.

Caption block:
Upper left: forward portion of the airship Enterprise. Front left seat is occupied by the pilot. Front right seat by copilot or by the operator of the flashing electric signs. Lower left: each segment of the sign fastened to the outside of the blimp can flash any letter in the alphabet, or any figure. Power for the Neon signs is provided by a special generator operated by one of the two engines. Each letter is tested before ship takes off. Upper right: Neon signs are operated during flight by a tape fed through a special machine. The tape is prepared before a flight by being perforated on this code machine. which operates like a typewriter. Lower right: instrument board of the Enterprise. Lower left and upper right photos by Rudy Arnold.
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