FlightGlobal.com
Home
Premium
Archive
Video
Images
Forum
Atlas
Blogs
Jobs
Shop
RSS
Email Newsletters
You are in:
Home
Aviation History
1942
1942 - 0620.PDF
264 FLIGHT MARCH 19TH, 1942 "*, WORLD PRESS SUMMARY RESUME OF TECHNICAL ARTICLES DEALING WITH AIRCRAFT AND ASSOCIATED SUBJECTS For the summaries and translations from aircraft and technical journals of the world, we are indebted to the • Directorate of Scientific Research and Technical Development, Ministry of Aircraft Production. i High-speed Jumps IF a parachutist opens his parachute whilst travelling through the air at a speed in excess of 250 km/h, the normal para chute is likely to burst. It is therefore necessary to delay the opening until the rate of descent has dropped to 65 m/sec. The author calculates the trajectory of the human body for a series of initial values of the speed 100 to 250 m/sec. and four positions of the original tangent to the trajectory (o°, — 300, — 6o°, and — 900), on the assumption that the terminal velocity of. a free drop is 61 m/sec. and the weight of body is 90 kg. From this he deduces the minimum delay time for the opening and the minimum altitude from which a jump can take place. If, for example, the pilot leaves a fighter aircraft flying horizontally at 540 km/h, the delay time is 3.7 sec. and the minimum altitude 115 m. If diving vertically at 720 km/h, the delay time becomes 8.9 sec. and the minimum altitude 920 m. Cases may arise where the pilot is forced to leave the aircraft at altitudes below the minimum value for the initial speed conditions. The full delay time is now obviously out of the question, but he may escape with his life if he waits with the opening till about 150 m. from the ground. This will require great presence of mind and at the same time an accurate eye for ground clearance. The latter quality can be trained. • Parachute Jumps from High Speed Aircraft.—(E. Muhle- mann, Flugmehr und Technik.) (Switzerland.) Joining Air Film IN the practical evaluation of aerial reconnaissance material it is frequently neeeaaary to dejd with short-length aero= films, usually those from the " AFA—I " aerial camera, The length of such films does not exceed 9 metres, and they are developed in apparatus designed for handling films of 28-30 metres in length, taking from 30 to 35 minutes for the operation. Consequently, if the laboratory receives three to six such films, it will require one and a half to three hours to deal with them. Furthermore, the utilisation of the apparatus will be one-third only of the designed capacity, and the con sumption of solutions and chemicals will be correspondingly excessive. The most economical method of treating such short films is,. therefore, to handle a number of them simultaneously by gluing them together into one strip. The gluing is performed in the following manner: Using a brufeh or a tuft of cotton wool, ordinary dope is applied to the emulsion side of the aero-film (about 4-5 cm. wide). Before the adhesive dries, the section to be joined on is applied with the gelatine side to the glued section, and rubbed down with a clean rag until the adhesive has dried. This method is reliable, the glued film does not tear when passed through the standard Air Force developing appliance, nor dissolves in the liquids used in the treatment of negatives: de-sensitiser, water, developer, fixing bath, or alcohol. A Device for Joining Short Lengths of Aerial Photo-films.— (K. N. Sakharov, Air Fleet-News.) (U.S.S.R.) Night Error THIS paper describes the development of a method enabling pilots to determine the accuracy of night bearings obtained by means of a radio compass in the wavelength range of 200 to 2,000 metres (150 to 1,500 kilocycles), and the effect on the indication when the aircraft passes through the combination of fields due to the reflection of waves from- the E layer or from a mountain side. Consideration is given to the appear ance of the night error on the ground and in altitude, taking into account the simultaneous presence of the direct wave, the sky wave and the sky wave reflected from the ground. It is demonstrated that the night error is smaller in the air than on the ground; also that there are regions in the atmosphere where the night error is very small. The dynamic aspect of the night error is then studied- i<^~ the case of an aircraft moving through the above-mentioned ^ system of waves. How the radio-compass indication changes regularly about a mean value, whether correct or not, accord ing to the polarisation of the sky wave, is next discussed. All cases of polarisation are examined. In conclusion, a number of rules are formulated relative to night direction finding on board aircraft above land or sea, supplemented by maps showing areas where direction finding is safe, unsafe or dangerous. The maps show that the practical range of night direction finding is increased substantially by the correct interpretation of the radio-compass indications. Control of Night Error in Aeroplane Direction Finding.— (H. Busignies, Procs. of I.R.E.) (U.S.A.) Petrol Poisoning TWO recent instances of poisoning by petrol fumes in flight -*• are described. Both refer to two-seater bombers with open cockpits. In one case the pipe line between fuel tank and engine fractured; in the second, the nipple on the fuel pressure gauge became unscrewed. In neither case did the defect reveal itself as a petrol spray or splash and the smell in the cockpit was not unduly marked. Nevertheless, the broken pipe led to both pilot and observer ultimately losing consciousness and being injured- in the subsequent crash. The consequences of the unscrewed nipple were not so serious, since the pilot landed soon after the smell became noticed. The landing was, how ever, very rough and the handling of the aircraft much below the standard for this pilot. The latter, however, seems to have been unaware of this. It must consequently be assumed that in both cases petrol poisoning in flight took place, owing to leakage and an accumu lation of highly concentrated fuel fumes in the cockpit. The handbook description of petrol-fume poisoning states: " Light cases of petrol or paraffin poisoning are manifested in the form of a light intoxication. The symptoms are hallucinations of short duration. In serious cases, reduced pulse with irregular breathing, contracted or dilated pupils, foam on the lips, cutaneous haemorrhage, and loss of consciousness." Loewe, Kolesnikov (Baku) and Lazarev (Leningrad) found, by ex periments on animals, that aviation spirit (pure) is a heart toxic. Excitation reactions are poorly developed. Insensibility results from a concentration of 0.05 (grammes?) per cubic metre after 4-5 hours. Since doped petrol was used in the above cases, the question arises whether poisoning was due to the petrol or the added tetra-ethyl lead. Acute tetra-ethyl lead poisoning, according to the instructions'for its use, is distinguished by the follow ing symptoms: insomnia, extreme excitation, visual and aural hallucination, delirium, talkativeness, insecure gait. In light cases, insomnia, nightmare, sickness, bad taste in the mouth, giddiness, headache, general lassitude. Characteristic for tetra-ethyl lead poisoning is a dormant form lasting several days. The official handbook states that, owing to the small per centage of addition, poisoning with doped petrol is hardly distinguishable from the effects of pure petrol. Comparing these descriptions of symptoms with the two cases quoted above, it may be concluded that, even if the dope participated in the effect, the principal poisoning #= by means of petrol. Neither did tetra-ethyl lead poisoiMg appear later. Conclusions.—(1) Acute poisoning by the fuel, in case of leakage in flight, is possible even in an open cockpit. (2) In both cases mentioned the poisoning manifested itself as rapid insensibility of a light nature, after a short previous excitation. Cases of Petrol Poisoning in Flight.—(P. F. Vokhmyani, Ait Fleet Neivs.) (U.S.S.R.)
Sign up to
Flight Digital Magazine
Flight Print Magazine
Airline Business Magazine
E-newsletters
RSS
Events
