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Aviation History
1929
1929 - 0962.PDF
FLIGHT, MAY 9, 1929 By H.mie BOW TO IKDIA SIR PHILIP SASSOON'S TOUR IN THE BLACKBURN "IRIS" Lecture by Sq.-Ldr. C. L. SCOTT, D.S.C., before R.Ae.S. SQDN.-LDK. C. L. SCOTT delivered a lecture before the R.Ae.S. andInst.Ae.E., on April 25 last, concerning the cruise to India and backcarried out last year by Sir Philip Sassoon in a Blackburn " Iris" flying-boat. As there are many points of interest, we give below this lecturein full. " Objects of the Flight" The objects of this flight were( 1) to enable the Under-Secretary of State for Air and the Director of Equipment, Royal Air Force, to inspect as manyas possible of the Royal Air Force Units in Egypt, Iraq, India, and Malta, and (2) to get some information on the behaviour of a large flying-boat operatingunder tropical conditions away from its base. " The Aircraft" The flight was carried out in the Blackburn ' Iris II' flying-boat with duralumin hull, fitted with three Rolls-Royce Condor III.A engines andfour-bladed wooden propellers painted with cellulose paint. Dual control was fitted and the two pilots sat side by side." The fuel was carried in three tanks attached to the under side of the top centre section over the three engines. Each of these tanks had a capacity of300 gallons and was fitted with a fuel contents gauge on the underside. Pipes were led from each of these tanks to a central junction box in the lower centresection and from this junction box three pipes were led to the three engines. Cocks, capable of being operated from inside the hull, were fitted to thesesix pipes and thus complete control of the fuel supply was obtained, " It was found in practice that, with all cocks on, the fuel did not drainequally from the two outboard tanks, and loss of lateral trim soon became noticeable. This was easily rectified by temporarily shutting off the supplyfrom the tanks which contained the less fuel. ** A biplane tail was fitted and there were three rudders, a servo rudderbeing fitted to the centre rudder only. The servo gear could be put out of action by means of a clutch operated from the pilot's cockpit. Two elevatorswere fitted, the upper and larger one being operated in the ordinary way by the control column, and the lower one being operated by means of alever in the pilot's cockpit. This fixed elevator took the place of an adjustable tail plane. " A small duralumin dinghy weighing about 80 lbs. was carried in aninverted position in the lower centre section. This dinghy carried five people and proved to be very useful. " Personnel and Loading" The crew consisted of two pilots, two fitters, one W/T. operator and one rigger. The passengers were Sir Philip Sassoon, Under-Secretary of Statefor Air, Air-Commodore Longmore, Director of Equipment, and a servant. " The normal service load of the ' Iris' with 680 gallons of fuel is 27,400 lbs.On this flight, with full fuel (900 gallons), the gross load was 30,350 lbs. For most of the stages only 700 gallons of fuel were carried, and this reducedthe gross load to 28,850 lbs. The maximum gross load at which the ' Iris ' has been flown is 33,000 lbs, " The Flight " The ' Iris' left Felixstowe on September 27 for Plymouth. Refuellingwas carried out on arrival, and the next day was spent in having a general look over the machine and engines. The passengers joined the ' Iris' earlyon the morning of September 29, and we left for Hourtin, near Bordeaux at 06.55 hrs. A certain amount of low cloud was encountered in the Channeland there were some very unpleasant hailstorms in the neighbourhood of Ushant. " After Ushant was passed the weather improved and we had practicallyno trouble from weather for the remainder of the outward trip. We landed near the French Seaplane Station on the lake at Hourtin and took in 400gallons of fuel in just over an hour. " Berre, near Marseilles, was reached just before dark the same day.From here Aboukir was reached in three days, via Naples and Athens. At Aboukir the passengers left the ' Iris' and proceeded to Khartoum and thenacross the desert route to Iraq by land aircraft. " The ' Iris ' spent six days at Aboukir during which time everything wascarefully inspected. The only defect found in the engines was excessive wear in several of the bushes in one rocker box The complete rocker box wasremoved and a new one fitted. " We left Aboukir for Alexandretta on October 8, and it was on this occasionthat difficulty was first experienced in taking-off with no wind. The tanks had been filled up to 800 gallons and the gross load was 28,820 lbs. Twoattempts were made to get off, but on neither occasion could an air speed of 40 knots be exceeded. One hundred gallons of fuel were then taken outreducing the load to 28,070 lbs. " Another failure was experienced, due to a slight swell which was runningEach time the fore part of the hull struck a swell the speed was noticeably reduced. The final attempt was made close i n shore to avoid the swell an«here we got off after a very long run. Our intention was to leave Alexaiidretta on October 10. We climbed to a height of 5,500 ft., but we were unable toget through the mountain pass owing to clouds and rain storms. " The weather was better the next day and we went through the pass at aheight of 4,000 ft. and picked up the Euphrates at Meskene after flying °ver the desert for about H hrs. The river was followed and a height oi over4,000 ft. was maintained because below this height the air was unconiturtaoi bumpy. We landed on the large lake of Habbaniya, about 60 miles snort 01Baghdad, shortly after mid-day. This was done as it was thought tnai it would be very difficult to bring the ' Iris' down in exactly the right spoiin the Tigris in the mid-day bumps. , tn" The soundings of the river we had, showed that an error of a few y;jrc1^ one side or the other of a definite line would mean running aground onsand bank. Those who have flown large machines in the'raid-day <>?d Iraq will, no doubt, appreciate this point. , e " We anchored in the middle of the lake, rigged the awning over us ipart of the hull, had a meal, and left for Hinaidi about an hour before sunsei. The next day we left for Basra, spent one night there, and then left for bt-niawith our passengers on board once more. , , 3n" It was when within about 100 miles of Henjam that our troubles <•<* • the Starboard engine suddenly dropped from 1,900 r.p.m. to I..WW.1;PSOThe engine ran quite steadily at this speed and there was no vior«u u , it was decided to carry on. _„ " After landing at Henjam it was found that when the engine w;?s i""^the A side camshaft remained stationary. On examination, tne • 380
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