Jump to content

303sqn

Members
  • Posts

    436
  • Joined

  • Last visited

Everything posted by 303sqn

  1. Paul Lucas Colour Conundrum A Tiger’s Tale RAF Tiger Moths based in the UK 1932 - 1945 Following the Munich Crisis, a decision that what were described as 'Biplane types of aircraft' were to be camouflaged by the manufacturers was communicated to the RAE on 13 December 1938 with a request that a camouflage diagram suitable for the Gladiatorbe drawn up. Subsequent to this, a letter from the Air Ministry to the RAE dated 7 February 1939 stated that Paintings for camouflage diagrams are required as follows (1) Camouflage Scheme for Trainer (biplane, single engined) aircraft; to be Air Diagram 1169 and to be based on Tiger Moth Drawing M6424, a copy of which is herewith except that approximately the upper third only of the sides of the fuselage is to be camouflaged.The top surfaces of the lower mainplanes are also to be camouflaged.The paintings should show the mirror image. The term 'mirror image' was a reference to the practice of preparing two versions of each camouflage scheme in which one was the mirror image of the other. Known as the 'A and 'B' Schemes, there were intended to be applied to alternate aircraft on the production line. The initial rough drawings for AD1169 entitled 'Camouflage Scheme for Single-Engined Trainer Aircraft' showing a Tiger Moth were submitted to the Air Ministry on 23 February 1939. These showed the upper surfaces to be finished in the Temperate Land Scheme of Dark Earth and Dark Green with the wing tips of both the top and bottom planes for a distance of 6 feet in from the tip, the interplane struts, elevators, fin and rudder to be Yellow. The upper surface of the bottom planes were shadow shaded in Light Earth and Light Green. AD 1169 was issued in March 1939 but despite the accompanying text on the drawings stating that the line of demarcation between the Yellow and the camouflage colours on the sides of the fuselage was to be one third of the way down the side of the fuselage, photographs of Tiger Moths finished in this scheme show that the demarcation followed a line approximately half way down the fuselage. Why this was the case is unknown. Where the fuselage roundel encroached onto the camouflage, a thin Yellow line appears to have been allowed to remain so as to make the roundel stand out…………………. Roughs for the new AD 1169, now entitled 'Camouflage Scheme for Single Engined Biplanes - Communications' were sent to the Air Ministry on 14 September 1939. The new AD 1169 was significantly different to the original version in that it no longer had Yellow wing tips or elevators and now contained a note which stated that the interplane struts should be finished in the same camouflage colour as they stood on.
  2. P8576 'CITY OF BUNDABERG & DISTRICT' was a IIB with a bulbous spinner and round oil cooler. Built in June 1941 and delivered new to 308 Squadron in July. It became the personal aircraft of F/Lt Stefan Janus.
  3. Aircraft 315 original Polish serial 8.51 evacuated to Romania pilot ppor. Pil. Hieronim Dudwał 113 EM. On 3rd, 4th, 10th September 1942 Elev Aviator Baltă Constantin practised inverted flight, rolls, aerobatic turns and formation flying with Lt. Aviator Micu Ioan as instructor. 6th May 1944 Slt. Aviator Instructor Baltă Constantin was credited with two B-24s destroyed and on 6th June one B-24 probable, flying as part of Flight School based at Ghimbav-Braşov airfield. SOC 08/01/1946 reason accident.
  4. It is not brass, it is or was black but most of the paint has flaked off. Fire extinguishers, until 1997, were coloured according to type/content. There five types/colours. Carbon dioxide black. Foam cream. Wet chemical yellow. Water red. Powder blue. Aircraft usually have carbon dioxide extinguishers and so are black in colour. In 1997 a new European standard was adopted. Now all extinguishers coloured red with a colour band indicating then type/content.
  5. No, most likely it is part of the oxygen dustribution system. It is certainly not an oxygen storage cylinder. Gas cylinders/bottles are colour coded to indicate the gas that they hold. This is very important for safety reasons. The colour code for oxygen is black and oxygen cylinders are black.
  6. Location looks like La Senia, Algeria. Vc ER180, MX/P had shark mouth marking but it is not the same aircraft as in the photo. ER180's shark mouth is slightly different and the eyes are just in front of the exhausts.
  7. Embarrassingly I have to withdraw my statement. I was fooled by Z1460 being stated as a Whitely. It was in fact a Wellington IV. Interestingly I also found N1480 listed as a Whitely. The accounts given by Cynk, The Polish Air Force at War, and Musiałkowski, Bomber Aircraft of 305 Sq say that the ‘Manston’ Wellington was Z1460/N. Both give lists of the Squadron’s Wellingtons. Cynk lists Z1480/N but does not include Z1460. Likewise Musiałkowski’s list has Z1480/N but also contains Z1460 but with no individual letter. So where does the serial Z1480 association with this Wellington originate? At present I do not know. However, I have found out more about Z1480. It was a 142 Squadron Wellington lost with it’s crew on 17th September 1942 on a mission to Essen. http://www.rafcommands.com/database/serials/details.php?uniq=z1480 Looking in the squadron’s ORB it is listed on the 9th and 12th of August. Z1460/N first appears in 305 Squadron’s ORB on the 18th August. So if the ‘Manston’ Wellington is Z1480 it would have had to have been transferred to 305 Squadron and then, after crashing at Manston, recovered, repaired and sent back to 142 Squadron in around three weeks. That, I think, highly unlikely. As for Z1460, its career came to an end with 104 OTU when it crashed on 17th July 1943. http://www.rafcommands.com/database/serials/details.php?uniq=z1460
  8. That’s the good side of N1460 SM/N (not N1480). On the other side the fuselage fabric was torn off from the wing root back to the tail. On the evening 28/29 August Polish squadrons provided 21 Wellingtons for an attack on Saarbrücken. N1460 was attacked by a fighter that made ten passes before it was shot down. N1460 was then attacked by another fighter that set it on fire and killed the rear gunner, Sgt Stefan Rueger. F/O Henryk Aleksandrowicz (nav), Sgt Mieczysław Ćwikliński (radio op), and Franciszek Kula were ordered to bail out. The first two became PoWs but Kula managed to evade capture and returned to Britain five weeks later. Unable to communicate with the rear gunner skipper F/Lt Tadeusz Czołowski thinking he might be wounded and unable to bale out, continued to fly the Wellington. 2nd pilot Mieczysław Seredyn managed to to put out the fire. The tail was not damaged and the controls still worked. They managed to force land at Manston. The aircraft was repaired and returned to service. My apologies for earlier stating the Wellington was N1460. Two references give this serial number but after further investigation N1460 does not appear to be the correct serial number. There seems to be some confusion over N1460, was it a Wellington or a Whitley?
  9. On 31 Match 1936, the Air Ministry wrote to the RAE asking them to consider the question of identification markings on aircraft. The RAE was asked to consider which size, style, and colour of letters and numerals were best for recognition in the air. The Air Ministry requirement was for a series of numbers to identify the squadron and a letter to identify individual aircraft within the squadron, all of which were to be visible at a distance of approximately 500 yards. Because it was anticipated that it might be necessary to employ different coloured paints for recognition from the ground during air exercises, paints of three different colours were required. The RAE was also to assess whether such markings had any adverse effect on the effectiveness of the camouflage scheme as a whole. When the trials were complete and decisions reached, a quantity of the three paints chosen were required for service trials in Air Defence Great Britain at the earliest opportunity. The Air Ministry also pointed out that as in practice, the squadron number would be on the rear of the fuselage, the RAE's trials should be carried out with this in mind. It was also to be borne in mind that the squadron number could consist of one, two or three figures and therefore the trials should include a three figure number as this was considered the most difficult to make out. The RAE wrote to the Air Ministry with its final report on 15 September 1936, stating that the three colours used during the trials were grey, dull red, and ident green. Two sizes of character were tested, the first being 48 inches high with 6 inch wide strokes, which were tested for visibility at 500 yards; and the second being 18 inches high with 2.5 inch wide strokes which was tested for visibility at 200 yards. Both sizes in all three colours were tested against an earth coloured background and a green coloured background, and it was discovered that the grey colour was the most visible in each case. On 7 October 1936 the Air Ministry wrote to the RAE to inform them that it had been decided to standardise upon the grey colour immediately. The RAE was therefore asked to prepare 100 Standards of the new colour on metal and a similar number on fabric and forward them to the Aeronautical Inspection Directorate. The material was to be bought to Specification DTD 314 and was to be called Sea Grey, Medium. Although the form and colour of the identification markings on camouflaged aircraft had been decided upon, the Air Ministry does not appear to have informed all Commands of the standardisation of identification markings on camouflaged aircraft until September 1937. A letter sent to all operational Commands on 28 September 1937 stated that the usual aircraft number was to be applied on the fuselage and under the mainplanes and that the squadron badge was to be applied in the position laid down in AMO A.24/37. The squadron identification number was to be applied forward of the national marking on both sides of the fuselage whilst the individual aircraft letter was to be applied aft of the national marking on both sides of the fuselage. The characters which made up these markings were to be 48 inches high and to be made up of strokes 6 inches in width with smaller characters only being used when the space available made such a course unavoidable. The paint to be used to apply the squadron number and individual aircraft letter was given as 'Stores reference :- 33B/157 Colour reference :- Sea Grey (medium).
  10. Because the Germans did not use red very much. One section (three aircraft) were painted with red diagonal stripes as part of trials to develop quick recognition markings. This is revealed in squadron correspondence. Ref 303s/5/6/Air. Date 18th September 1940. From Officer Commanding, No 303 (Polish) Squadron R.A.F. Station, NORTHOLT. To Officer Commanding R.A.F. Station, NORTHOLT. With reference to your NS/9/9/Air dated 16th September, 1940, enclosing copy of Headquarters No. 11 Group Signal S.230 dated 16th September 1940, giving instructions to paint a red band round the fuselage of our aircraft, this has now been done on one section, and stands out well. 2. The following points are made in respect of this policy:- (1) The enemy aircraft are painted many colours on top notably yellow, orange, black and white. (2) The enemy fighters have a better performance at above 20,0000 ft. there policy is to camouflage underneath, but when seen from above they are easy to recognise. (3) It would appear that our policy must be to remain camouflaged when seen from above, and be easy to recognise from below. P3120 flown by: 15/09/40 P/O Henneberg, F/O Januszewicz 17/09/40 F/O Januszewicz 18/09/40 F/O Urbanowicz 26/09/40 F/O Grzeszczak 30/09/40 Sgt Szaposznikow 01/10/40 Sgt Szaposznikow, V6665 flown by: 09/09/40 F/Lt Kent 11/09/40 Sgt Brzezowski 15/09/40 F/Lr Kent 17/09/40 F/Lr Kent 26/09/40 Sgt Andruszkow 27/09/40 Sgt Andruszkow The identity of the 3rd aircraft is not known.
  11. In the early days after the chessboard was adopted the way it was painted varied. Later it was standardised with the red squares top left and bottom right. After the defeat of Poland the Air Force reformed in France and were allowed to display the chessboard on the side of the fuselage of their aircraft. As a gesture it was painted in reverse, or as some say negative, and it was to remain in this orientation until Poland was free again. In Britain it was just down to whim. After the collapse of the Soviet Union many of the Eastern European countries discarded their Soviet era markings and reverted to those used in the past. In a 'Me Too' moment the Polish government joined in and ordered that the orientation of the markings be reversed.
  12. The red has been painted over with white, normal practice in the Far East.
  13. Try the Key publications forum. https://www.key.aero/forum/historic-aviation
  14. I would ignore the restoration, they seem to have just painted on the letters JEJ in the usual fashion which is probably not correct. There was a profile in the October 2006 issue of Model Aircraft Monthly MV268 which has JEJ in large white letters forward of the roundel as in the above photograph. There are two photographs of his last Spitfire, MV257, on page 31 of 2nd Tactical Air Force vol 1. The wings are not clipped and JEJ (Sky on the profile) in small letters in front of the pennant.
  15. Thanks for that. Cristofin may have been based polyvinyl acetate, perhaps with latex. Formvar was the name used by Monsanto for the polyvinyl formal resins they manufactured/sold. Made by reacting polyvinyl alcohol and formaldehyde as copolymers with polyvinyl acetate and used in coatings.
  16. Weybridge Blade, made by the the Airscrew Company Ltd, were covered with Hessian, Jabo blades with cellulose acetate or cellulose nitrate, Hudulignum with Cristofin. Cristofin was developed by Hordern Richmond but I cannot find out exactly what it was, maybe a type of Formvar. Late in the war Jablo blades switched to using Cristofin.
  17. THE USE Of WOOD FOR AIRCRAFT IN THE UNITED KINGDOM Report of the forest Products Mission June 1944 Three types of propellers made from compressed wood are now in production in the United Kingdom and several other types are in various stages of development. Fixed-pitch, wood propellers of conventional type are in extensive use on various training airplanes. Weybridge Blade This blade, which is made by the Airscrew Company, Ltd., is carved from a blank glued from boards of Douglas-fir scarf joined, at the root end, to "Jicwood” or to similar “compreg" supplied by firms in the United States. Jicwood, supplied by the firm, Jicwood, Ltd., associated with the Airscrew Company is prepared by coating Canadian birch veneers with about 4 percent by weight of a spirit-soluble phenolic resin, drying, and then consolidating the pack under heat and pressure. The resin content and the conditions of pressing are such that Jicwood is not stabilized appreciably either by the resin or by the action of heat and moisture. The blank is rough-carved by machine, and then finish-carved and balanced by hand. Due principally to the time required for conditioning at various stages of manufacture, the elapsed time for a blade in production is from 7 to 12 weeks. In one type of finishing, the blade is covered with hessian cloth cemented in place. A brass leading-edge strip is sweated to brass gauze and hammered, screwed, and riveted in place. A thick sheet of either cellulose nitrate or cellulose acetate is cemented on and the whole blade is placed in a rubber bag and put in an autoclave. In the autoclave treatment the coating is said to penetrate the Douglas-fir blade to a depth of about 1/8 inch. In the second type of finishing the blade is liberally spread with a thick lacquer and a sheet of cellulose ester is rolled into place on each face, forming laps at the leading and trailing edges. After the coating has shrunk, the laps are carefully sanded. Final balancing is done,by local scraping, and, if necessary, balancing paint is used locally. These blades are repaired by splicing a new piece to the undamaged portion. Although repair of a damaged root is never attempted, the entire Douglas-fir portion of the blade may be replaced, the new scarfs nearly coinciding with the old. If the coating is not too badly injured, it is repaired locally. Hydulignum Blade The Hydulignum blade is manufactured by Hordern Richmond Aircraft, Ltd. One thirty-sixth-inch birch veneer is coated with approximately 20 percent of Formvar (polyvinyl formal) by weight. After the solvent (trichlorethylene and alcohol) has been driven off, the veneer is pressed into panels of specific gravity 0.95 at an elevated temperature and then cooled in the press. Two corners of the board are trimmed off and that end is then further compressed sidewise to a specific gravity of 1.3. The final board thus has a high-density double-compressed root, a transition zone, and a medium-density blade and tip. After rough patterning, several boards are assembled into a blank with a cold-setting urea-formaldehyde glue and the blank is carved in the same way as the Weybridge blade. After several coats of primer containing chlorinated rubber, and of Formvar varnish have been applied, a brass leading-edge strip is riveted and screwed in place. About 14 additional coats of Formvar complete the blade. A particular advantage claimed for the Hydulignum propeller is that the equalized shear strength in the root, in the two planes parallel and perpendicular to the glue surfaces, permits the use of smaller diameter hub fittings. Practical considerations requiring the use of a standard hub for all-wood blades, however, has precluded the use of a smaller hub for the Hydulignum blade. Jablo Blade This type of blade is manufactured by F. Hills and Sons, Ltd., and Jablo Propellers, Ltd. Veneers 0.6 mm. (1/42 inch) thick and of varying length are interleaved with phenolic-resin film glue and assembled in such a way as to give boards of 69 plies at the root and 48 at the tip. The assembly is pressed to a uniform thickness at a gradually increasing temperature reaching a maximum of about 280° F. The boards are roughly profiled, then assembled with casein glue. Carving is done by machine, followed by manual final carving. A stocking of phosphor-bronze gauze is stretched over the blade and soldered along the trailing edge. After application of a brass or steel leading-edge strip, many coats of phenol-formaldehyde enamel are brushed on and baked so as to build up the surface flush with the metallic sheathing. After a final balancing, the blade is given a coat of grey primer and one of cellulose-acetate lacquer. (Since the return of the Mission, it has been learned that the type of finish described for the Jablo blade is no longer employed and has been replaced by a finish similar to that of the Hydulignum blade. This leaves two types of propeller finishes in use; namely, (1) cellulose acetate or cellulose nitrate (cellulose esters), and (2) "Cristofin," as developed by Hydulignum.) Experimental Blades F. Hills and Sons, Ltd., have three new types of propeller blades in development: the Norton, the Trafford, and the King. The Norton blade is made from boards each of which has approximately the same density throughout its length. The blank is glued up with four outer boards of specific gravity 1.3, and three inner boards of specific gravity 1.1. The Trafford blade has a root consisting of alternate boards of specific gravity 1.3 and 0.9 scarfed to a blade of natural spruce to which are also glued densified birch leading and trailing edges of specific gravity 0.9. Both these types were designed to minimize the strain on the press Caused by eccentric loading. In addition, the Trafford is expected to be lighter and stiffer than the Jablo. The King blade is a molded, uniform-density, hollow blade. Birch veneers mm. (1/8.5 inch) are tailored to a calculated shape, rolled into long tubes, impregnated with a phenol-formaldehyde resin, and dried. A large number of these tubes are loaded side by side into a steel die having a solid steel core. Heat and pressure flatten the tubes and consolidate the into a blade Of specific gravity 1.3 with a maximum wall thickness of about 3/4 to 1 inch. The core is removed after the pressing. If successful, this type of blade will have equal shear strengths in two directions, will save veneer and resin, and will be adaptable to the Hamilton standard hub. F. Hills and. Sons, Ltd., is also considering the use of Zebwood, a veneer-plastic composite for propellers. Molded Components, Ltd., have molded experimental blades of impregnated veneers pretailored to shape. Each of the two faces of the blade consists of nine continuous plies, a feature that avoids excessive exposure of end grain and glue lines and provides a skin running the full length of the blade. None of the wood blades now in production can be fitted satisfactorily to the Hamilton Standard hub, which requires a hollow root. They are all used with the Rotol hub of British manufacture. A threaded conical ferrule is used on all wood blades and is cemented in place with "Semtex," a mixture of Portland cement and rubber latex. Considerable interest has been shown in the new lag-screw retention developed at Wright Field. Although Jablo and Weybridge blades are balanced against masters, Hydulignum blades are still furnished only in matched sets and are not interchangeable.
  18. Hydulignum Two-way Compression Produces Improved Material for Airscrew Blades Flight 26th November 1942 There is of course nothing fundamentally new in making airscrew blades of compressed impregnated wood. Large numbers of British military aircraft are fitted with such blades, and they are giving very good results in service, not to mention that their uses saves a great deal of duralumin, which becomes available for other purposes in aircraft manufacture where it may be a better material than wood. The Hordern-Richmond Aircraft Company has been experimenting for years of methods of still improving plastic-bonded woods for airscrew blade construction. They have now evolved, not so much a new material, but rather a method of manufacture which, it is claimed, results in improved shear strength and greater homogeneity. Briefly explained, the new method is based on compression of wood in two directions instead of in the one direction hitherto customary. The orthodox method of making wooden airscrew blades is to coat layers wood veneer with thermosetting resin, place them in a heated press in which the wood is compressed and the resin softened. Upon cooling, the plastic sets and bonds the veneers together at decreased size and increased density. Thermoplastic Resin Used In the Hydulignum process (the name given by Hordern-Richmond Aircraft Company to the new method) the wood veneers are not only compressed flat-wise but also edge-wise. Obviously it would be possible to use a thermosetting resin for bonding, but that would mean the two-way compression would have to be carried out in one operation (the expression “thermosetting” being applied to plastic which softens on the application of heat, sets when the heat is removed, but does not soften again upon a second application of heat). For ease of manufacture, and also give better control of density, it was preferable to compress the wood veneers in two stages; first in the normal way and afterwards edgewise. That meant that a thermoplastic resin (one that softens on a second application of heat) had to be used instead of thermosetting. After extensive research into various vinyl resins, Formvar [the registered trade name of the polyvinyl formal resin produced by Monsanto Chemical Company) was chosen as having the most suitable characteristics: high temperature softening point, lack of brittleness at low temperatures, and great toughness and durability. In the first operation the wood is compressed to a density of about 60 lb/cu.ft., from the p original 40 lb/cu.ft. or so. It has been found that any pressure beyond this results in spreading the veneer and consequent loss of strength. The edgewise compression is applied while the veneers are still under heat and pressure on top and bottom and bottom surfaces. By suitable choice of edgewise pressure, which is not necessarily the same as the flatwise, the density can be very accurately controlled, and a homogeneous material results. It has been found that blocks of Hydulignum can be left for almost indefinite periods without deterioration, and if, after forming the blade, any reaction should take place due to shrinkage or expansion under extreme conditions, this is equal in both directions so that ovality is avoided. In hydulignum the material is, as already mentioned, compressed in two directions. By exhaustive investigations into the degree of compression in each direction, a perfect balance of shear has, it is claimed, been obtained, giving high shear values. These higher values can, of course, be used to give a stronger blade for a given root diameter, or alternatively, to retain the strength with a blade route of smaller diameter. The need for four-bladed airscrews to absorb the power of the newer high-power engines without “going the whole hog” and using contra-rotating airscrews, has made this question of blade root diameter important, and it would appear that Hydulignum offers considerable advantages in this direction. By way of demonstrating the feasibility of making wooden airscrew blades with small roots, Hordern Richmond Aircraft obtained some damaged blades from Curtiss hollow steel electric airscrews. These blades have roots of very small diameter, and it has been thought almost impossible to make a wooden blade strong enough for such as small blade root. The actual steel shank was sawn off and heat treated so it could be pressed into a conical shape. It was then used as an adaptor into which the wooden blade root was screwed. Tests on the ground indicated adequate strength, and the complete set of blades was made flown on an American aircraft with satisfactory results. With the object or reducing root size to a minimum, Hordern-Richmond Aircraft have devised a very clever adaptor in the form of a internal-threaded plug screwed into the end of the airscrew blade and locked to an external sleeve of opposite thread. The shear loads are thus divided between the part of the blade root engaging with the normal external sleeve and that engaging with the inner plug, thus increasing the threaded area, and with it the shear forces which the blade is able to withstand. There was a time when it was thought that wooden airscrew blades would be inferior, aerodynamically, by reason of the fact that the blade sections would have to be thicker than those employed with metal blades. This does not apply to the high-density, compressed-wood, blades, and full advantage of this fact has been taken in Hydulignum blades, which compare in aerodynamic efficiency with metal blades. The homogeneity of the material has enabled the manufacturers to shape their blade sections to the forms dictated to aerodynamic considerations, and the balancing, which is normally done by shaping the blades, is carried out in an entirely independent manner. Here it might be explained that balancing of airscrew blades is done around two axes, one in the plane of the blades and one at right angles to this, known respectably as horizontal and vertical balancing. In the Hordern-Richmond airscrews, horizontal balancing is done by means of a weight in a bush fitting into a bore in the blade root. This bush can be threaded and used as a plug for horizontal balancing. Vertical balance is obtained in a very ingenious way by lead quadrants which can be adjusted to bring the centre of gravity of the blade into any desired position in the plane of the blade.
  19. The Station Flight at Skeabrae was equipped mainly with Mk VIIs. Usually one flight of the squadrons sent north was based on detachment at Skeabrae while the other flight was based at Sumburgh with Mk Vs. It was customary for aircraft, including Mk V and Mk VI as well as Mk VII, to remain at Skeabrae and units posted normally consisted of pilots and ground crew who took over the Skeabrae aircraft leaving their own aircraft behind. Over a year 312, 118, 453, 602 and 313 squadrons passed through Skeabrae. After 312 Squadron left in September 1943 the Spitfires continued to use 312's DU codes. It is believed that this was an oversight by the squadron replacing 312 Squadron and this became an entranced practice. This was not unique, Northolt Station and Wing Headquarter Flights used SZ codes. The Czechs used three Spitfire VIIs, MB763/DU-W, MB765, MB828. Later there was another, MD122/DU-Z. MD114/DU-G was allocated to the Station Flight Feb 1944. Operationally, the Skeabrae Mk VIIs saw little use. 312 Squadron did not report any operational flights with the Mk VII between August and October 1943. 118 Squadron, which replaced 312 in October did not use the Mk VIIs either and 453 Squadron flew one uneventful scramble on 7th November. F/O McDermott, MB828/Y and P/O Ferguson, MB765/G to 37,000 ft without finding the three bandits that had vanished. Only three flights out of 50 were flown on Mk VIIs during November and two out of 50 during December and none during January. 602 Squadron replaced 453 in mid-January but the Mk VIIs were only used to complement aircraft numbers and regarded as main equipment. Three flights out of 14 were recorded during January and four out of 50 in February with the first victory for a MK VII from Skeabrae. 602 Squadron was replaced by 118 Squadron who recorded only two scrambles. On 21st May, W/OA A Taylor in MD122 and F/Sgt C H P Bayton in MD138 and on 30th May F/O J J Parker RAAF in MD118 and W/O A Taylor in MD138. The first time the section returned to base with nothing to report, the second, shot down a Ju 88 approx 25 miles from Kirkall. It was the second and last victory for an Orkneys based Mk VII. 313 Squadron arrived on the 11th July with a significant number of pilots that were non-Czech. Operations began the next day and uneventful scrambles and patrols are recorded that month but generally air activity was low. 313 Squadron continued to use their time flying the aircraft of the Skeabrae Station Flight, usually to train pilots with no experience on the type. The Mk VII seems to have been used during July and August only. On the 15th July P/O Robert E Dodds wrecked MB763/DU-Z when he overshot on landing and tipped up. The incident in The Big Show that Clostermann says took place on the 21st February 1944 actually took place on the 20th February. Operational records and combat reports do not mention Clostermann having any part in the combat. On the 20th February F/L W.G.Bennetts and F/O 'Ian' Blair made an uneventful scramble in Mk Vs at 10.55. Two hours later they were called for another scramble. This time Bennetts taking off in Mk VII MB763 DU*W and Blair in Mk VII MD114 DU*G. They climbed to 32,000 ft and saw vapour trails. Ground control confirmed it was an enemy aircraft. Blair gave chase but the EA spotted the Spitfires and turned for home. Blair opened fire at extreme range with no result. Bennett opened fire at 250 yards but his gunsight stop working and he broke off. Blair closed and fired at 200 yards. The starboard wing of the EA broke off and fell into the sea. The pilot, Oberleutnant Helmut Quednau of 1.(F)/120 was killed in his Bf 109 G-6/R3 coded A6+XH. Debris from the EA hit the radiator of Blair's Spitfire and he made a forced landing at Stronsay.
  20. MSG was used for codes with the TL Scheme, DG/DE. Sky with the DF Scheme, OG/DG MSG undersides.
  21. Not really, but that was WWI to make methyl rubber and methyl rubber is made from methyl isoprene. They manufactured a different synthetic rubber in WWII that didn’t involve coal. Germany were desperate as regards rubber in WWI. Britain controlled the trade in rubber and would not let anyone sell rubber to Germany. So Germany started to recycle as much rubber as possible. They collect production scraps and end up confiscating car and bicycle tyres from civilians. There was even a sort of black market in the German ports. Ships’ crews would buy small rubber good such as raincoats and hot water bottles that they could sell for fantastic prices. Perhaps not surprisingly recycling attempts proved insufficient so they tried other ways of making tyres. Tyres made of wood or wood covered with leather or canvas were tried. That didn’t work out very well. Next were springs inside steel bands. Not successful. They tried refacing old tyres with rivet studded leather filled with a gelatinous substance instead of an inner tube. Friction heats the tyres, the jelly melts and runs out the holes in the tyres. By 1915 all the rubber they can find has been reclaimed and recycled. Engineers have tried every substitute for rubber they can come up with. Then someone recalled that there were some pre-war trials in making a synthetic rubber from 2,3-dimethylbutadiene, commonly called methyl isoprene. In 1910 a pilot plant had been constructed to make methyl isoprene. In 1912, after initial testing, Dr. Carl Duisberg, director of Bayer, presented a car fitted with methyl rubber tyres to the Kaiser. He was well impressed. Over 4,000 miles without a puncture, a considerable feat for that time. In June he announced that he was extremely satisfied and ordered his entire fleet of vehicles to be fitted with the ‘puncture proof’ tyres. In fact it would be a remarkable achievement for the tyre to have a puncture as they were made from solid rubber. The biggest problem with methyl rubber was that it was degraded by oxygen. So after a few more tests the chemists decided that methyl rubber was useless. A small amount of methyl rubber remained at the partially dismantled pilot plant, and after some testing, the methyl rubber was deemed to have sufficient properties to warrant large scale production. However, there was another snag. The method of synthesising methyl isoprene required acetone and aluminium. Acetone was being used to manufacture explosives. Acetone can be made from wood or calcium acetate but these supplies were quickly depleted. It can also be synthesized from acetic acid (vinegar). Acetic acid is produced by the of fermentation of grain or potatoes, but everybody needs to eat. The chemists were only allowed to use rotten potatoes, and that didn’t work well because the bacteria used for the fermentation are rather particular what the eat. So the chemists to came up with a roundabout way of synthesizing methyl isoprene. Germany has a lot of coal and lime so they start with those. Heating them together produces calcium carbide. The carbide will react with water to produce acetylene. The acetylene is then reacted with more water in the presence of a mercury salt to form acetaldehyde. This is then oxidized to acetic acid, which is then heated with more lime to form calcium acetate. The calcium acetate is dry distilled to make acetone. The acetone is treated with an aluminium salt and caustic soda to form an aluminium salt of pinacol. The resulting salt is then simply distilled under pressure to form methyl isoprene. Having now a method of manufacturing methyl isoprene they need to polymerize it to make the rubber. At this time polymer synthesis was in its infancy, and any kind of polymerization takes several months to reach a high conversion. After an enormous number of experiments, three methods were chosen. First, the methyl isoprene is stored in tin drums at 30oC for six to ten weeks, H-rubber (hart-rubber, meaning hard) is formed. This hard rubber is used for hard rubber goods such as submarine battery boxes, and cases for other electrical equipment, and is found to have better electrical resistance than hard rubber made from natural rubber. Second, the methyl isoprene is stored in iron drums at 70o C for three to six months to produce W-rubber (Weich-rubber, meaning soft). This is used for soft rubber goods such as belts, hoses, tyres, and anything else that needs a flexible rubber. W-rubber is difficult to vulcanize, and the crosslinked product is only elastic when warm. Solid tyres made of the it are hard, and in the winter, large chunks will fall off when a vehicle is moved after staying in the cold overnight. Ideally these vehicles would be placed in heated garages for the night. On the battlefield cars have to be jacked up when left standing to prevent the tyres from getting flat spots. At least this poor substitute for natural rubber tyres was better than, wood, steel, and squirting melted jelly. The third type of methyl rubber is formed by allowing the methyl isoprene to stand in contact with sodium wire in an atmosphere of carbon dioxide. This was called B-rubber and it was used for insulating wires and coating balloon fabric. By the end of the WWI they were producing about 150 tons of methyl rubber per month. A total of 2,500 tons were produced in all, and factories are being built to increase production. As soon as the armistice is signed production stops. However, with British restrictions on rubber supply the search for a synthetic rubber continues especially in the United States, Germany, and the Soviet Union. In Germany they turn their attention upon butadiene because it can also be made from acetylene in a process very similar that used to make methyl isoprene. The procedure is too expensive for a rubber made from butadiene to compete with natural rubber commercially, but the Germans persist. To begin with the butadiene is polymerized with sodium metal in much the same way that the "B" type methyl rubber was made. This butadiene-based rubber was called Buna, Bu for butadiene and na for natrium, the Latin name for sodium. The rubber produced was both expensive and inferior to natural rubber. So the sodium polymerization was abandoned for an emulsion polymerisation. This method was cheaper but took weeks to reach high conversion. Research was conducted on finding a catalyst to speed up the reaction and, slowly, the reaction time was reduced from weeks to days, and finally a few hours. Then the Nazis come along with the goal of achieving maximum self-sufficiency, no food or chemicals will be imported into Germany. German rubber companies are forced to use the new Buna rubber, which isn’t much good at this time. The rubber companies hate using it, but they have no choice. Then Dr. Walter Bock and Eduard Tschunkur found a solution. They exchanged 25% of the butadiene for styrene which was cheaper. This new rubber, called Buna-S, (S for styrene), had much better wear resistance in its raw form than even the highest quality natural rubber. There was still a problem. The Buna-S rubber cannot be compounded and vulcanized easily on the machines made for natural rubber. A softening agent can be added to make the compounding easier but then the improved properties are lost. The rubber companies are forced to use the new rubber, no matter how difficult it is. Initially, almost 7% of their rubber consumption is required to be the new Buna-S rubber. Complaints get worse, until there is another development. In 1934, Eduard Tschunkur and Erich Konrad decide to exchange the styrene of Buna-S rubber with a more expensive chemical, acrylonitrile. This results in a new product, Buna-N or Perbunan. This new rubber has really great properties, like Buna-S, but with the added bonus of oil resistance. The rubber companies no longer complain so much. Even though it is only a speciality rubber, it is worth the effort to process it. It also makes the German government happy, because there is no need to import the American oil resistant rubbers, Thiokol and Neoprene. There was a lot of interest in synthetic rubber in the USA which led to considerable co-operation between the two countries. Julius Arthur Nieuwland was born on February 14, 1878, in the town of Hansbeke, Belgium. Two years later the his family emigrates to South Bend, Indiana, close to Notre Dame (the university not the cathedral). He becomes interested in botany and enrols at Notre Dame, where he studies Latin, Greek, and botany, and prepares to become a Catholic priest. After receiving a degree from Notre Dame, he enters graduate school at the Catholic University of America in Washington D.C. and begins research on acetylene, which would develop into an obsession. As a priest, ordained in 1903, and a doctoral candidate, Nieuwland writes "Some Reactions of Acetylene," in which he outlines the procedure for reacting acetylene with arsenic trichloride in the presence of aluminium chloride to form a poisonous gas which would later be developed (not by him) and called Lewisite . After receiving his PhD he returns to South Bend to take a position as a professor of botany to finance his one passion outside the Church, acetylene research. In 1906, Nieuwland passes acetylene through a solution of copper and alkali chlorides that would, unknown to him, take him into the world of synthetic rubber. The only thing he does know is that this reaction evolves a peculiar odour, but no solid or liquid products. Years pass, and all attempts to isolate this mystery substance fail. In 1918, Father Nieuwland is made Professor of Organic Chemistry. Then, in 1920, after 14 years of research, there is a breakthrough. By changing the catalyst and the acidity of the mixture, the rate and conversion of the reaction are greatly increased. Father Nieuwland sets up an apparatus to collect the gas and is surprised to find that he has collected a yellowish oil as well as the gas. The oil is identified as divinyl acetylene, which, after a while, thickens into a jelly and then into a hard resin which tends to explode when handled. Despite the danger, Father Nieuwland and his group continue research with the oil. One fateful day in 1923, they react the divinyl acetylene with sulphur dichloride, and produce a substance with elastic properties resembling rubber. This product is too plastic for commercial use. Two years later, while giving a lecture before a gathering of organic chemists in Rochester, NY, Father Nieuwland makes a casual mention of his discovery. Present is Dr. Elmer K. Bolton, of the DuPont laboratories. His ears gentleman's parts up at this aside. He and his co-workers have been searching for synthetic rubber with some interest in acetylene, only to meet the same disappointment that all previous attempts at synthetic rubber had brought. After patent arrangements were made, a team of 28 scientists at DuPont, led by Wallace Carothers, took over commercial development of Nieuwland’s discovery. The first specimens of divinyl acetylene rubber are a great disappointment. No two samples have the same properties and all samples fail to retain their elasticity for a satisfactory period of time. DuPont’s scientists turn their attention to the gas monovinyl acetylene. Nieuwland suggests that the gas be treated with hydrogen chloride, and a thin, clear liquid is produced and christened chloroprene. When polymerized, chloroprene forms an elastic material very similar to fully vulcanized rubber, except that the new material is resistant to degradation by oil, sunlight, and air, and chlorprene rubber does not require the addition of sulphur for vulcanization. Low molecular weight polychloroprene is sold under the trade name DuPrene, and later Neoprene, as a speciality rubber but receives little attention as the public has become accustomed to hearing about the great new synthetic rubber which turns out to be useless. After tyres are made and tested by Dayton Rubber Manufacturing Co., in Dayton, Ohio, and a report of satisfactory performance is released in June, 1934, the public begins to take notice. With the synthetic’s resistance to chemicals and weather, production of chloroprene rubber gets under way. Nieuwland has a pair of heels made of DuPrene for the shoes he wears on a tour of Europe in 1934. The shoe's soles wear out, and the heels are transferred to another pair. He also has a DuPrene fountain pen set made as a gift for the Pope, but he forgets to take it with him. These days few have heard of Nieuwland. He was an unassuming man who stayed mostly in his laboratory. He refused any royalties on his creation due to his vow of poverty as a priest. In 1922, Dr. Joseph C. Patrick, Kansas City, is trying to make an antifreeze. He mixes ethylene dichloride and sodium polysulfate and finds that instead of antifreeze he has made a milky suspension. Allowed to coagulate and dry, the product bounces and stretches like raw natural rubber. If this product is heated, it will crosslink without the addition of sulphur needed to vulcanize natural rubber. He knows he has made a marketable synthetic rubber. The raw materials are easy to make, it takes no effort to make the rubber, and it can be made in many different grades. He also finds that, unlike natural rubber, his new rubber has oil resistance. He calls it Thiokol. Thiokol is put into commercial production by the Thiokol Corporation of Yardville, NJ in 1930 and is sold as a speciality rubber for about $0.30 per pound, 2 or 3 times the price of natural rubber at the time. Thiokol's only problems are it's strong sulphur odour, lower elasticity than natural rubber. It also releases fumes that make you cry like when you peel an onion when it is being processed. People are willing to suffer a little, however, and pay the extra cost due to Thiokol's great oil and solvent resistance. In October 1930 Standard Oil and I.G.Farben formed JASCO, the Joint American Study Company, as a forum for getting patents on joint projects. The originator of the new technology will have a 5/8 interest in the new patent, and the other group a 3/8 interest. Through this JASCO arrangement, German Buna rubber technology came to America. This all goes well until the start of World War II when both the American and German governments frown on the two companies working together. Standard does not want to loose all the time and money they put into getting Buna rubber ready for market, and I.B.Farben does not want to just give it away. So, in 1939, the companies write up the Hague Agreement, in which Standard gets the rights to all JASCO processes, including synthetic rubber, in the United States, Great Britain, and France, while I.G.Farben gets the rest of the world. Standard buys back it's stock for $20,000 and calls it even. So the rights to German synthetic rubber technology comes into the hands of the Standard Oil (NJ) Company. Not nearly as exciting as industrial espionage, but important to history. Buna-N was introduced to the United States by accident in 1937. The DuPont neoprene plant is out of commission for a long time due to an enormous explosion, so no one can buy any neoprene. The rubber trade has become accustomed to using the oil resistant rubber, but there is none to be had. Some companies can use Thiokol instead, but most cannot. In a desperate attempt not to lose any customers, DuPont asks I.G.Farben for some samples of it's new Buna-N rubber. After testing, DuPont finds the rubber to be satisfactory and orders enough to supply it's customers. Slowly, American use of German Buna-N rubber increases, even though it costs almost 10 times as much as natural rubber at that time and 30 to 50 cents more than neoprene. Once the American rubber companies see how good Buna-N is, they start requesting samples of Buna-S, and the German companies realize that their product isn't so bad after all. In 1932, while Standard and I.G.Farben are busy working together to make Buna rubber a marketable product, another type of synthetic rubber is being being created. In April Frank Howard of Standard is meeting with Dr. Martin Müller-Cunradi of I.G.Farben. Dr. Müller-Cunradi hands Howard a jar of a clear viscous fluid, which, he says is a polymer of isobutylene, a well known by-product of oil refining. Howard knows that people had tried to polymerize isobutylene in the past, but had only succeeded in joining a few molecules. Long chain polymers had never been made, a high molecular weight is needed. Howard take a peek at the research lab where he is shown the process for making this polymer. Liquid isobutylene is placed in an open beaker which is packed in dry ice. Dry ice is also placed in the beakers where it dissolves in the isobutylene. Boron fluoride, a gas is poured into the beaker, there is a small puff, and the beaker overflows with a spongy solid that can handled like a soft snowball. Howard takes this back to the Standard research labs, where they work on it and christen it Vistanex. It goes on sale in the winter of 1933 as a thickener for oils and greases. Because it is less affected by temperature changes than ordinary oils it is highly suitable for use in cars and hydraulic systems that experience large temperature fluctuations. Vistanex is also found to have some rubber-like properties, but it has no double bonds for vulcanization and is not strong or elastic enough in it's raw form to compete with natural rubber. Initially, the isobutylene used to produce Vistanex is synthesized, but research is being conducted carried out on how to remove the isobutylene present in refinery gasses. At that time there was no use for isobutylene and it was is usually just burned. That would change. While all this messing about with synthetic rubber had been going on, there had also been developments in the petrochemical industry. The increase in compression ratio of each new engines increases power output and fuel efficiency, but also increases the tendency of the low quality gasoline of the time to knock. Dr. Graham Edgar of the Ethyl Corporation invents the octane scale system using isooctane as the standard. Every fuel company wants isooctane so they can rate their gasolines. Some want to use the isooctane as fuel itself for aircraft and auto racing. They think, "Why waste time with low grade gas if I can get the "super-fuel" that the whole rating system is based on?" It costs around $1,000 a gallon. (No, I haven’t missed out a decimal point). It so happens that you can make isooctane by the co-polymerisation of isobutylene. With all of this demand, Standard Oil want in on the action. It doesn’t take long for them to they work out that by purifying the refinery gases, diisobutylene and triisobutylene, it can be can be obtained. The diisobutylene can be hydrogenated and the triisobutylene can be passed over a catalyst to form isobutylene, the starting material for Vistanex. Standard oil spent years tinkering with the process for making Vistanex. They improved it to the point that it was practically indistinguishable from raw natural rubber, but it still could not be vulcanized. In 1937, Dr. William J. Sparks and Robert M. Thomas mix up a batch of Vistanex in a washing machine they had bought at the local department store. They added a small amount of butadiene, in with the isobutylene. When the spin cycle finished Butyl rubber had been born. Butyl rubber holds air 13 times better than natural rubber, and has excellent resistance to ageing, weathering, chemicals, moisture, ozone, temperature extremes, and tearing. It does not bounce at ambient temperatures, which makes it a great shock and vibration absorbing material, and best of all, the raw materials are plentiful, easily obtained, and cheap. The next problem is how to make it on an industrial scale. Chemists Sparks and Thomas want to make it in a batch reactor, a sort of giant washing machine. The projects engineer, A. Donald Green, rejects that. He had studied at the Massachusetts Institute of Technology where he learned that the most efficient and cost effective way of making chemicals is through a continuous process and he gets his way. At the start, the rubber keeps clogging up the reactors, causing frequent shutdowns. Eventually, the engineers get the sort out the problems and in 1943 the first batch of Butyl rubber is produced for market at the Baton Rouge facility. Back in 1940. President Roosevelt had declared that rubber to be a "strategic and critical material". This was brought about because German U-boats are blocking Atlantic shipping lanes, and there is a fear that the Japanese will stop shipment from the Asian rubber plantations. In June of 1940, the Rubber Reserve Company is founded to stockpile rubber in case rubber become unavailable. The RRC was also given control of the production of the raw materials needed to make synthetic rubbers, the production of the rubber, and the fabrication of products from the rubber. The patents and rights to these processes are given to the RRC through an information sharing agreement between Standard Oil, Goodyear, B. F. Goodrich, Firestone, and U.S.Rubber. On December 7, 1941, the Japanese attack Pearl Harbor and go on to invade South-East Asia where the rubber plantations are. The United States is cut off from 90% of the rubber producing countries of the world. In early 1942, the American Synthetic Rubber Research Program begins. Together with the major rubber producing companies, 11 university research groups, including Carl "Speed" Marvel at the University of Illinois, Izaak "Piet" Kolthoff at the University of Minnesota, and W. D. Harkins and Morris Kharasch of the University of Chicago, join the effort to make synthetic rubber work. Their goal, set by the RRC, is to set up four plants which will produce 30,000 tons each of Buna-S type rubber per year. By the end of 1942, the four plants are up and running, but falling short of their target. By the end of 1943, 15 plants were in operation, and supply finally began to meet demand. The technology chosen for synthetic rubber production was based on Buna-S research because Buna-S could be mixed with natural rubber and milled on the same machines, and because the raw materials (the monomers) were available. Buna-S is particularly suited for tyre treads because it resisted abrasive wear; and it retained sharper impressions in moulds, calender rolls, and extruder than natural rubber. But the synthetic rubber was more difficult to make, had less tackiness, and required more adhesive in making a tyre than natural rubber. These problems had to be overcome to produce a reliable general purpose rubber. On March 26, 1942, the representatives of the companies and the U.S. government agreed upon a “mutual recipe” to produce The Buna-S rubber. The recipe consisted of monomers butadiene (75%) and styrene (25%), potassium persulfate as a catalyst or initiator, soap as an emulsifier, water, and a modifier, dodecyl mercaptan. Because Buna-S required different compounding conditions, accelerators, antioxidants, and types and amounts of carbon black than natural rubber, the program’s leaders realized that a research and development program would be necessary to solve the existing and potential problems of Buna-S manufacture. The research strategy during the war is on gradual improvements of existing processes. For example, if the rubber is allowed to polymerize until all the monomer was exhausted, long, branched molecules are produced, which gel and make the rubber difficult to process. To solve this problem, the reaction was only allowed to proceed to 72% conversion and a mercapten modifier, a chain transfer agent, is used to control molecular weight. It was also found that the polymerizations have an induction period which varies from batch to batch. The researchers at the University of Illinois find that this is due to different fatty acids present in the different soaps used for the emulsion process. These soaps also cause the solution to foam during the recovery of the remaining monomer. This problem leads to the development of candellia wax and silicone defoamers. The properties of the Buna-S type rubber are highly dependent on the amount of styrene in the rubber so it is important to know how much styrene had been incorporated. William O. Baker of the Bell Telephone Laboratories solved this problem by developing a procedure for determining the amount of styrene using the refractive index of a solution of the rubber. Under the American Synthetic Rubber Research Program, the different types of synthetic rubbers are given code names, all of which start with GR, for government rubber. Buna-S rubber is known as GR-S (S for styrene), Butyl rubber is called GR-I (I for isobutylene), Thiokol is called, GR-P (P for polysulfide),Buna-N is known as GR-A (a for acrylonitrile), and Neoprene is called GR-M. The American Synthetic Rubber Research Program and the RRC succeed in producing a lot of synthetic rubber in a short amount of time. In 1942, 3,721 tons of GR-S are produced increasing to 182,259 tons in 1943. In 1944, the year of peak demand, production tripled to 670, 268 tons, and by 1945, production had increased to 756, 042 tons. Although this might not seem like much, but, at the time, it is a huge success. One which eventually helps the United States and it's allies to win the war.
  22. No. Rubber is not black, synthetic or natural. Tyres are black because the contain carbon black, up to 50%, typically 25%. It adds strength and resilience, better traction with less wear, protection from UV light and oxidation. It also helps dissipate heat preventing the tyre getting too hot and going pop. Larger amounts are used when there is a need to prevent the build up of electrostatic charge. For example tyre on a fuel truck. White tyres contain zinc oxide. Make the treads from carbon black rubber and you have white-wall tyres.
×
×
  • Create New...