Measures Against the Cold
The oil-tank on a Dornier-Wal stands with one of its sides outside the engine-gondola’s wall. This side is furnished with cooling-ribs for cooling off the oil. On our machine the tank was designed right into the engine’s gondola and therefore any cooling off was unnecessary. In addition to this capsules were built over the motors so that the heat from the engines could be kept in the gondolas without cooling down like the temperature outside. All the pipes were bound many times round with linen strappings. Certain pipes had the inner layer of bindings of felt. This provision was made both as a means of isolation from the cold and to prevent “burst pipes.” Experience here in Norway and in other lands shows us that most motor trouble on a long flight originates in one or other of the pipes. The motor conducts itself well generally. Truly I have seldom, if ever, seen a motor-construction so free from vibration as on our machines and therefore there was little possibility of burst pipes. As a safety measure, all the same, I regard such binding as necessary. To the cooling water we added 4% pure glycerine and thus had a mixture which would not have frozen before we had -17° c. and we did not have such a low temperature up in the ice regions. All the same we took the precaution of tapping the water down on to one of the petrol tanks whenever it was not necessary to be ready to start at a moment’s notice. By a special contrivance we could pump the water direct from the tank into the radiator again. We generally started the engine first, then pumped the water up. I should like to explain why. The lower part of the intake-pipe was encompassed by a water-cap through which a smaller quantity of the cooling water is led for the purpose of warming the pipe. When the propeller starts to turn, petrol begins to flow, lowering the temperature in the petrol pipe considerably below atmospheric temperature. The walls of the water-cap take on the same low temperature immediately. If the cooling mixture at this time stands at a temperature which is barely a few degrees above water’s freezing point, one runs the great risk of there being so much freezing that the exhaust of the cap will be blocked. If this occurs the cap will in one moment become a solid block of ice, causing the sides to burst in consequence. Should one, on the contrary, start the engine first and fill up, the cooling water will thus, in its passage through the cylinders, be so warmed when it reaches the cap that this calamity will be avoided.
As indicated above, we do not tap the water when we must be ready for an immediate start. In order to keep the temperature in the motor gondola so high that nothing should freeze, and the engines at the same time should be absolutely ready for a start, we used the Therm-X apparatus. This is the first time I have learned that this apparatus bears this amusing name; hitherto I believed it was called “Thermix.” (That is what we called it up in the ice and that is what we are going to call it henceforth!) This apparatus was constructed specially for us by the Société Lyonnaise des Chauds Catalytiques, and was made in a size and form suitable for placing under the engines or under the oil-tanks. Their manner of action was, otherwise, exactly the same as the ordinary Thermix apparatus. We had six apparatus in each gondola and could thus, in a short time, raise the temperature to 35° above atmospheric temperature.
In the early days “up in the ice” we took the Thermix apparatus down in the mess when the cooling water was tapped off. They warmed the place up so well that we found it really pleasant and comfortable. In the evening when we separated to go to bed, we divided the apparatus amongst us in the three sleeping compartments, and there we slept in a little Paradise (as compared with the later times) when of necessity we had to economize, even in the small quantity of petrol which they used. There we hung our frequently soaking-wet socks, goat’s-hair socks and shoes, directly over the apparatus to dry. I remember still how comfortable it was to put on the warm dry footwear in the morning. During the time that we were not able to use the Thermix apparatus we had to lay our stockings on our chests when we went to bed in the evening—a not too comfortable proceeding. The high temperature we were able to keep up in the body of the plane when we had the apparatus going prevented the machine from freezing fast in the ice. There was always a tiny little puddle outside the body of the machine.
In order to be able to warm up the motor and the oil with the help of this apparatus, it was necessary that we should start the engine, screw out the sparking plugs in each cylinder, warm it up well, and set it ready for starting again. This prevented moisture gathering on the plugs. To help to get the petrol warm we ran along the petrol pipes with a large soldering-lamp to help to make the petrol flow easily. On account of these preparations we never had starting difficulties; the engines started at once.
In case the petrol might be thick and slow in flowing we had brought with us a quantity of naphtha with which to spray the cylinders. We never needed, however, to make use of it.
The radiator was equipped with blinds, with which we could regulate the radiation. They were of untold benefit to us. When the blinds were fully barred, it took much less time to warm up the motors before attempting to start. We used thus less petrol for warming up. To get the greatest possible power out of the engines we could, by regulation of the blinds, keep the temperature almost at boiling point at the start, damping down later by opening the blinds wider.
That the compasses were filled with pure spirit, and not with the spirit mixture, was of course a necessity. The same referred to the levels and the water levels. Even though oil might not have frozen in the event of our having had an oil level, it would in any case have acted too slowly in the cold atmosphere. Moreover all the movable parts of our instruments, which were designated for use in the cold regions, were smeared with a special kind of oil which had been tested in a temperature of -40° c.
In my portion of the book I must make special mention of the pilot’s rig-out. For flying in a cold temperature it is of the greatest importance that the pilot, who must sit still the whole time, should be warm and appropriately clad. It is easy to find the most beautiful heavy leather suits which can withstand every attack of cold and frost, but it is not so easy to find garments which are appropriate for all circumstances. Even though the pilot has to sit still he must have freedom to move about without his clothes handicapping him. They must in all respects be easy and pliable. What is most important is that they should be absolutely suitable for any work which may be needed before the start. I shall try to explain why a little more intimately. There will always be one thing or another to be done immediately before a start is made, and as far as we were concerned we might have to land to take observations at any time, and start off again immediately afterwards. If during such a landing we kept on all our flying clothes as we moved about the ice, we should quickly become much too warm; our underclothes would become clammy, causing us to shiver when we should once again rise in the air. Had we only one heavy outer set of clothes, and we took it off for any reason, we should risk taking severe cold, and would start flying again thoroughly chilled. Our outer clothes were therefore arranged in several plies so that without waste of time we could take them off or put them on again to suit the temperature, according to whether our work was strenuous or not. Our undergarments were presented to us by the Norske Tricotagefabrikanters Forening. They were made after we had had a conference with one of the manufacturers, H. Meyer Jun. Next the skin we wore a quite thin woolen vest and a pair of pants of the same material. On the top of these we had a pair of heavy pants and a vest of Iceland wool. Then long trousers, and a jumper, with a woolen helmet to pull over the head. Rönne had made these suits which were of a thin comfortable wind-proof cloth (a present from A/S William Schmidt, Oslo). This was our working kit and also our skiing rig-out intended to be worn should we eventually have to set out on a march to reach land.
The flying suits were composed of a roomy jacket and long trousers of thin pliable leather with camel hair outside. The leather suits were presented to us by the Sporting Outfitters, S. Adam, Berlin. On the top of these we wore a sealskin “anorak” (Eskimo jacket with peaked hood). This outfit was made absolutely to accord with the demand of the aforedescribed conditions.