History of Aviation - Chapter 5.1
Cross-country flying differs from ordinary airdrome flying in that it takes you a long way off from your landing field. On the airdrome your chief anxiety is to learn how to fly, how to work the controls, how to bank; but in cross-country work, you are supposed to have all the technique of, airplane operation well in hand, so that you do not have to think much about it. In cross-country flying, then, your chief anxiety will be to arrive at your destination and to be constantly searching out available landing fields in case of engine failure. The first cross-country flight you make may be a short, easy one, in which there are plenty of available landing places, and on which you will be able to make a regular reconnaissance report. Further experience in cross-country work will involve more and more difficult trips, until you will think nothing of flying, for example, on long raiding tours over unfamiliar enemy country.
Equipment.-Knowing that you may have to land far away from any headquarters, you must take a complete set of tools and covers for the airplane. Your clothing need not be different from usual, and will comprise helmet, goggles, - leather suit, and gloves. Do not forget your handkerchief, which you frequently need to clean off your goggles.
The instruments needed on a cross-country are: a compass, which should be properly adjusted before starting and the variation angle noted. A wrist watch is necessary; ordinary dashboard -clocks go wrong on account of the vibration. Take an aneroid barometer with adjustable height reading. Of course you will depend upon a revolution indicator, for no acuteness, and he will fall back on the revolution:
indicator for assistance. The air-speed meter, whether of the Pilot type or pressure-plate type, will prove invaluable in flying through clouds or mist when ground is obscured. Also the inclinometer able to give the angle of flight when the earth not visible, although the speed indicator usually is -sufficient to give the angle of flight, for an increaser of speed means downward motion and decrease of speed means upward motion. Additional instruments may be used.
Map.-The map is essential for cross-country work. It should be tacked on to the map board if -the flight is short, but made to run on rollers if the flight is long. In the latter case the map is in the form of a single long strip, while your flight may be full of angles; therefore you will have to practice using this sort of map, in which the corners of your flight are all drawn as straight lines. The scale of maps may be 2 or 4 miles to the inch for long flights. This scale is sometimes spoken of as a fractional figure; that is, 2 miles to the inch is the same as 1/127,000 scale. The map should be studied most carefully before the start of the trip The course which - you propose to fly should be marked out on it; all available Landmarks which could be of service as guides should be distinctly noticed and marked on the map where necessary. These landmarks will in case there is no wind enable you to make your trip without using the compass at all, and in case of wind, are essential as a check on the compass. Mark off the distance in miles between consecutive points of your course. Mark the compass bearing of each leg of this course.
As landmarks towns are the best guides, and they should be underscored on the map, or enclosed in circles. It is customary not to fly actually over towns. Railways are very good assistance to finding your way, and these should be marked on the map in black wherever they approach within 10 miles of the course. Mark water courses with blue color, and roads with red.
Landmarks.-Only practice can make a pilot good at observing the various features of the ground beneath him. The various features which can be used as guides are those which are most visible After towns, railways come next in importance Their bridges, tunnels, etc., make good landmarks On windy days when relying on the compass, it will be well to keep in sight of a -railway even if this be
the longer way around, because the railway constant check upon the compass bearing. case you will have noted on your map a magnetic bearing of the railway, which bearing you can readily compare
with your compass Moreover, the railway is good in case you involved in a fog or mist for a time. It should remembered, however, that on most of the map distinction is made between one and two-track roads; also that it is easy to make mistakes where branch lines are not shown on the map because they are dead ends leading to private quarries, etc.and, may be taken for junctions-. Railways sometimes seem to end abruptly, which means that you looking at a tunnel.
Water is visible from a great distance. Cautions to be observed are that after a heavy rain small flooded streams may take on the appearance larger bodies of water or lakes, which you will ""~ difficulty in reconciling with the map. Small rivers -are often overhung with foliage, and to follow the in all their curves will waste a lot of time.
The use of roads as guides may be governed by -the fact that paved roads are usually main roads -and telegraph wires may be expected along the In the newer parts of the United States the system -of laying out roads provides a very useful means of gauging distances; I refer to the section system which is in use, for instance, in Illinois, where the is a road every mile running north and south, --that the entire country is cut up into squares -mile on each side, with occasional roads of course at ½-mile and 1/4mile points.
Navigation by Landmarks.-In all cases of cross-country flying the pilot will have two independent systems of maintaining his proper directions: first, the computed compass bearing; second, the use of landmarks whose position is known. In comparing his computed course with the course actually indicated by passing over these landmarks the rule should be made that, in case of doubt when a landmark is not distinctly recognized, take the compass course; there are many chances that a landmark may be altered or even removed without being so recorded on. the pilot's map, whereas the errors of the compass of course are presumably understood by the pilot who has secured every opportunity to check it when passing previous landmarks. It is important to note time of completing successive stages of the flight, that is when passing over predetermined landmarks. Time is a very uncertain condition to ascertain in airplane flying for it seems to pass quickly on calm days but slowly when the journey is rough. If the pilot does not check the time interval between successive objects he is quite likely to expect the next before it is really due.
Landing Fields.-Next to the ever-present worry which the pilot has regarding the perfect operation of his engine, the most important thing about cross-country flying is that wherever he may be he must have available a landing field within gliding distance in case his engine defaults. The question of course immediately raised, "What if there landing field within gliding range?" The a to this is that the pilot will instinctively -keep his eyes open for landing possibilities e minute of his progress whether he expects to them or not; in cross-country flying the lookout fields is first and foremost in his mind; if there no fields, it is up to him to pick out a spot of which is the least objectionable for a landing. the State of Illinois the question of landing almost non-existent, because there are large, -fields and pastures in almost every square mile the farming district, and a cross-country flight from Rantoul to Chicago could have no terrors for beginner as regards the choice of a landing ground.
When it comes to a cross-country flight like Ruth Law's, from Chicago to New York, these favorable conditions begin to disappear after the middle of the journey, that is, east of Buffalo. The most ideal condition for cross-country flying would be one like that on the London-Edinburgh route, where landing grounds are so frequent that by flying at a height of a couple of miles the pilot can free his mind completely of the worry of suitable landing places; but in the United States we have very few _ established airdromes, and the only approach to the London-Edinburgh route is the St. Louis-New York route, where the jumps are approximately 150 miles; namely, St. Louis, Champaign, Indianapolis, Dayton, Sandusky, Erie, Hammondsport, Philadelphia, and New York. That is why long cross-country trips are such an adventure in this country and such an ordinary affair in England..
The beginner will have special difficulty in training his mind to pick out available landing places; first of all because the earth looks so different from the sky that it is only with practice a beginner learns the shades and hues of color which mean certain kinds of ground, or learns to spot the different features of flat and hilly country. Even for an accomplished pilot it is hard to tell whether a field is good or bad from a height of over 1000 ft.; and as it is dangerous to fly this low over unknown territory, you can at once see what is meant by the worry of scanning the countryside for available fields.
Choose the best field that you can get, having a smooth surface and being easy to get out of in all directions. The following considerations are intended as a guide to what constitute the best field, in case you have a choice between several possibilities.
1. Choose a field near a town if possible, or failing that, near a main road or at least a good road. Remember that a field which appears to be near a town from the air may actually turn out to be a long walk after you have landed there and find that there are various trips to be made to and fro between your chosen landing spot and the town for the purpose of securing ropes, gasoline, supplies, etc. If you land near a main road there will probably be telegraph wires along it, which are undesirable in the case of a small field and wind direction such that you to rise off the field over the telegraph wires. It is often hard to distinguish between main roads minor roads, and it will be wise to look for the number of vehicles on any road in determining whether or not it is the main road.
2. The best field is a stubble field, and is numerous of course in the fall when the crops are It will have a lightish brown color when seen r height, and is pretty sure to be smooth, without ditches or mounds. Grass land is next best, but often full of mounds. Plowed, furrow fields are be avoided. It might be said that stubble f will be hard to get out of after a wet night. Vegetable and corn fields have a dark green appearance which the pilot must learn to distinguish from pastures, etc. If you choose pasture land, remember that in summer evenings the farm animals will generally be lying down near the hedges.
3. Avoid river valleys for landing over night, as there is liable to be a fog in the morning.
4. Any field which has been previously used for landing with success by an army officer can be wisely chosen.
The final determination of landing field characteristics can be made when your airplane has descended to a height of 1000 ft. off the ground, and in case you are not making a forced landing and your engine is still going, you can check up your estimate by descending to this level.
Proper Dimensions of Fields and Airdromes.- There are three kinds of flying fields. One ~ the airdrome which is used exclusively for flying and may be as large as a mile square; very few of these will be found in cross-country flights in the United States. Second, there is what is called the "one-way" field, a long, narrow, open space which is usable when the wind blows parallel to its length. Third, there is the "two-way" field, which has two sufficiently long runways at right angles to each other. A two-way field is very much better than a one-way field, inasmuch as you can always head within 45 degree of the wind, whereas in a one-way field an extreme case would be 90 degrees. Moreover, two-way fields, such as the crescent-shaped field at Dayton, Ohio, sometimes permit of almost universal direction of flight. The two-way field may be crescent shaped, T-shaped, or L-shaped. An L-shaped field should have each arm 200 by 300 yd. Under certain conditions there may be buildings located inside or outside the angle which do no harm aside from creating eddies in case of strong wind. A I-shaped field should also have its arms 300 by 200 yd. in size.
Regarding the size of fields it can be said that, while the JN-4 machine will rise off the ground after a run of 100 yd. or so, a field of this length is of course not big enough for frequent use, especially if bordered by trees, telegraph lines, fences, and so forth. A field for temporary use should be at least 200 by 200 yd., about 9 acres.
If obstructions at the edges are more than 5 ft. add to this 200 yd. a distance equal to twelve the height of the obstruction. For a permanent field 300 yd. is the minimum dimension necessary for clearing obstacles and must be increased if trees exceed 50 ft. in height. This minimum dimension assumes hard ground and the possibility starting in any direction. Training fields are mile square or more.
Whatever field is used either temporarily permanently by the pilot should be absolutely familiar to him over every inch of its surface. adjacent country should also be absolutely familiar to him from the standpoint of possible forced' landings which he may have to make during his flight he should make a habit of informing himself as to the woods and hills, etc., which can affect air currents in the neighborhood of the field from which he is going to start.
Guide Posts on Airdromes.-Some fields have pot holes in them, and these holes should be marked in each case with a large high red or yellow flag. Dc7not use short, small flags, as they will frequently be invisible to pilots taxying on the ground. All telephone wires, etc., should have large blankets or other suitable signals hung over them to warn the pilot away.
Commonly accepted marks for designating a landing spot on airdromes are as follows:
For day use a large letter "T" lying on the ground, made out of white cloth strips 15 by 3 ft.
This letter T is shifted with the wind so that its long leg always points in the direction of the wind and the pilot will therefore have nothing to do in landing but approach the letter "T" from the bottom, so to speak.
For night flying a system of four flares is used, so arranged that the pilot in making a proper landing will pass flare A on his left; within 50 yd. further on, flare B; then 100 yd. further on, flare C, also on his left. In passing flare C be will have a fourth flare, D, 50 yd. to his right. That is to say, the four flares make the outline of a letter "L" and the pilot approaches the letter "L" having the long leg on his left. The flares may be made by putting half a gallon of gasoline into a pail. This will burn for 30 mm. and will be visible 8 miles away. Sometimes at night instead of flares white sheets can be spread on the ground and a shaded lamp used to illuminate the sheets.
All searchlights on the landing field should point in the direction of landing. All other lights within a distance of a mile should be extinguished, and red lamps should be used at danger points.
On moonlight nights the same signals and guides may be used as in the daytime.
Pegging Down an Airplane.-In landing for the night do not stay up until it gets dark but choose a landing place which will allow you to come down 1 hr. before dark; this amount of time will be needed for laying up the machine over night. As you come to the landing ground note the time so that you can compute the actual duration of your flight in report, then make a good landing. Taxy machine to the spot where you intend to lea' over night, such as the lee of a hedge, etc.; there is no choice of position taxy the machine to -the approximate location from which you will your start next morning; this will save trouble you get ready to start.
Dismount from your machine, lift up the enough to leave the wings edgewise to the wind, machine, of course, facing the wind, and jack up tail in this position by the use of any convenient prop. Lash the control wheel or joy stick fast in fixed position so that the wind cannot flap the control surfaces around and damage them.
Choose a sunken trench if possible in which wheels may be sunk; if the wind is going to blow and there is no sunken trench it will be wise to dig one so that the effect of the wind on the airplane will be ~ lessened. If the trench is not necessary, at least 1:put chocks under the wheels. Peg down the wings -and the tail to stakes driven into the ground using rope if you can get some or lacking this in an emergency fence wires which you can secure by -means of your wire cutters. Do not lash tightly. enough to induce strains in the framework of the machine.
Next, fill up the tanks if a supply of gasoline or oil is available. Put the covers on the propellers, engine, cowls, etc., in order that rain and dew shall do no damage to these parts. The wings and body are varnished waterproof and will not be seriously damaged by a little moisture; to avoid the collection of moisture in the wings small boles are sometimes set in the wings at the trailing edge to let out the water.
Of course, you will engage a guard to watch the machine all night; see that a rope is strung around the airplane to keep off the crowd which may collect.