FlightGlobal.com
Home
Premium
Archive
Video
Images
Forum
Atlas
Blogs
Jobs
Shop
RSS
Email Newsletters
You are in:
Home
Aviation History
1956
1956 - 0691.PDF
FLIGHT, 1 June 1956 691 CORRESPONDENCE ... making this necessary. The manufacturers have had some rottenluck, especially D.H., but although I sympathize I do not feel they should be allowed to weaken B.O.A.C.'s position in the com-petitive field. I still plead, as I did in February, for B.O.A.C. to be given greater freedom, and I wish those who are taking theplace of Sir Miles Thomas the same success which he has achieved. London, W.I. - ;:*'. ICARUS. Flight-Refuelled Airliners ? > * is preventing the wide use of Sir Alan Cobham'sflight refuelling system by B.O.A.C. and other airlines? Is it really, as has been suggested, funk of an airliner flying in forma-tion with a tanker? Sir Alan's system has been widely adopted by the U.S.A.F. and now there is an American Air Force aircraftbeing flight-refuelled throughout the 24 hours. Maybe the American civil airlines will adopt it soon, so that their jet air-liners can become airborne at a more reasonable weight. Then we shall discover, too late, that if the Comet 4s had been adaptedfor flight-refuelling, we could have had the first non-stop jet airliners on the North Atlantic run.London, S.W.3. GEOFFREY DORMAN. Memories of the D.H.9A £I T always inspires a thrill to read about the aircraft we flew inthe "first war" and I have followed with pleasure the articles recently appearing in Flight. The subsequent correspondence shows the measure of theinterest created, and the letters referring to the D.H.4 and D.H.9 series have held a special interest for me. I had, however, beenhoping that someone would write about the D.H.9A, a develop- ment of the D.H.9, but powered by the 400 h.p. Liberty engine.[Since this letter was written Mr. J. M. Bruce's article on the D.H.9A has been published; the second part appears in thisissue.—Ed.] The 9A was a splendid aircraft, and received with joy bythose who were about to go out to France on daylight bombing. One of your correspondents refers to the D.H.9 as being verymuch under-powered. I never heard this criticism made. It is true, however, that the D.H.9A, with its greater power, had asuperior performance, and would climb, with its warload of three 112-lb bombs, its single Vickers gun in front and twinLewis guns at the rear, with several hundred rounds of ammuni- tion, to 15,000ft in 50 minutes. Our operating height on servicewas 17,000 to 18,000ft. Because of its greater weight, the glide when approaching toland was much flatter than that of the D.H.9, which presented some difficulty at first; but most pilots quickly adapted themselvesand became expert at handling tnis aircraft. My Squadron—110—was tne first (and, I believe, in the eventthe only) D.H.9A squadron to go out to France; this was in August 1918. We became part of Trenchard's Independent AirForce, with our aerodrome at Bettoncourt, south of Nancy. The D.H.9As of 110 were presented by the Nizam ofHyderabad, and each plane had the fact proudly recorded on each side of the centre section. We penetrated, for those days, deep into the Rhineland to bombsuch towns as Mannheim, Frankfurt and Kaiserslautern. While we maintained good formation we were either left alone or snipedat from a safe distance by the greatly outnumbering German "scouts" always trailing us; but any straggler was quickly pouncedupon, and our casualties were very high. It was held, however, that the Independent Air Force hadachieved its objective in lowering the morale of the Rhinelanders. Undoubtedly we were responsible for quite a diversion from themain German war effort in terms of aircraft and anti-aircraft concentrations. Sanderstead, Surrey. W. ARMSTRONG. FORMATION AEROBATICS (continued from page 665) As early manoeuvres become relatively easy, so are the moredifficult ones introduced, until the aircraft and pilots alike are being flown to their absolute limits. A detailed examination of a simple manoeuvre, a 180-deg turn,may illustrate the difficulties involved. The aircraft are flying in echelon starboard at about 400 kt, when the leader initiates aturn to port. Each aircraft rolls about its own longitudinal axis until the required 70 deg of bank is attained, and they are in a5-g turn (Fig. 5). At this stage No. 4, on the end of the line, is flying around an appreciably greater radius than the leader,having accelerated some 15 kt during his couple of seconds taken to apply the bank. When the leader has turned far enough, hestarts to roll out. No. 4 has then to close his throttle so as to lose excess speed and maintain his position. If, at this point, theleader decides that he has turned too far, and reverses his bank, No. 4 is apt to slide ahead, fully throttled back. When the forma-tion rolls out of this starboard turn, No. 4 is now travelling more slowly than No. 1 and, being throttled back, is unlikely to beable to get the engine revs soon enough to catch up. This applies also to the other team members who not only haveto juggle their throttles to keep in position, but must avoid using either full power or no power, in order to give No. 4 achance. Thus, if Nos. 3 and 4 were thrown out of position, a good No. 3 would not heave on full throttle to regain his position,but would leave a few revs in reserve to allow No. 4 to keep up, and they would regain their positions together. As a rule,the leader leaves his throttle set at the revs which experience has shown to be best for the particular routine. On occasionshe helps the rest of the team to change formation by judicious use of his throttle, but it is essential that he does exactly thesame thing every time the manoeuvre is rehearsed. A good example of this is the roll, changing from line asternto box in the process. Assuming a fairly high rate of roll (neces- sary in a compact routine, to avoid covering too much ground)it is impossible for the formation to catch up with the leader before the roll is completed, unless the leader throttles back atthe start of the roll, and opens up again when the team is in box. This, however, is an exception, and the leader keeps hisrevs steady most of the time. For the other pilots, a little anticipation of throttle movementsis desirable. This is possible because the leader constantly calls his intentions over the R/T. On take-off he will call "Rolling... NOW" and each pilot releases his brakes at the same moment. In the air he calls "Pulling up for a roll to starboard . . . rolling. . . steep turn port . . . wing-over starboard . . . line astern— GO . . . pulling up for loop . . . box formation—GO" . . . andso on. After each change of formation it is helpful to the leader if the last man in position gives a "blip" on his transmit button.He is too busy to speak! Although the R/T is so helpful, it is essential that, if a team member has a radio failure, he can continueround the set routine and change formation in the correct places. Experience has taught us that the interest of the crowd tendsto waver if the landing is included as part of the display. With swept-wing aircraft the landing is inevitably preceded by afairly drawn-out circuit, particularly if the aircraft are in forma- tion. It is probably better to finish the show with a decisivemanoeuvre such as a "bomb burst," fly away and return later in the programme for a normal tight break and individual landings. Each succeeding generation of aircraft has its own peculiarlimitations. No jet aircraft swings like a Spitfire, but the Spitfire pilot could slam his throttle and expect an immediate surge ofpower. Modern axial-flow jets have an acceleration time which is quite acceptable for operational purposes, but seems an eternityto the team member struggling to regain his position! When the Spitfire pilot closed his throttle the aircraft immediatelyslowed down. A Hunter seems willing to continue at undimin- ished speed almost indefinitely. Powered controls take muchof the physical work out of formation aerobatics, but make it a little more difficult to hold a rock-steady position. I am, how-ever, far happier attempting the more advanced manoeuvres in a Hunter than in, say, a Meteor. This is a tribute to the sensitivityof control and extra "urge" available in the former aircraft. To sum it up, it seems to me that the perfect team—if sucha thing could exist—should aim at a complicated routine, in- volving many artistically executed formation changes; they mustnever get too far away from their spectatorsand must strictly pre- serve the continuity,thus ensuring that there is literally "never a dullmoment." The author of this article. On his Hunter and his helmet are painted the "Fighting Cocks" insignia of No. 43 Sqn.; and his muffler repeats the chequer- board squadron marking.
Sign up to
Flight Digital Magazine
Flight Print Magazine
Airline Business Magazine
E-newsletters
RSS
Events
