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The Fifth Air Congress

The Fifth Air Congress 220 AIRCRAFT ENGINEERING September, 1931 Th e Report of th e Paper s Read and Discussions Durin g the Proceeding s at the Hague Reviewed by Dr . N. A. V. Piercy some interesting Swedish tests on spinning to senting the whole glider-drag of th e craft, and a last Th e two volumes recording the work of the destruction (with the aid of a parachute). The ter m being added to include climbing a t vertical Congress together run t o some 1,700 pages. The accoun t is wort h study. As a result it is proposed presentatio n is good, and several lecturers have velocity w. On all counts , then, t o introduce a fourth control, a "spin-rudder," graciously met ou r peculiar national difficulty by giving their papers in English. The summarie s in designed to create pitching moments when the tail Frenc h are also a great help. sideslips. Several papers bear directly upon the ever- Many of th e contribution s have already appeared urgen t question of airscrew body interference. in AIRCRAFT ENGINEERING, amongst these being So th e overall efficiency is Mr. Lock gives an ordered survey of the well- Sir Richard Glazebrook's account of aeronautical known, long and careful research which he an d research in England ; Mr. Relf's description of th e other s have conducted under the wing of the new variable density tunnel; Major Green's dis­ Aeronautical Research Committee. Herr Helmbold cussion of th e use of steel in aircraft ; and Messrs. where sets aside much of th e intricat e detail tha t we have Mitchell and Clifton's analysis of tank tests on grown accustomed to, an d develops the work of T o eliminate the outflow remaining in (8), from floats. It is propose d here t o refer t o a few papers Froude . Some indication of his reasoning and th e two expressions for N: of practical interest which may no t be so widely results should prove generally useful as a basis for known. exploitation in troublesome circumstances. Vol. 1 includes several papers on radio, lighting, an d other general matters essential to traffic. Mr. Helmbol d on Airscrew Theory or, writing k for Capon, on flying and landing in fog, mentions H e proceeds on th e following assumptions: An various new devices which have narrowed risks in airscrew with an infinite number of blades giving giving blind-flying, except - in mountainous country, negligible torqu e a s du e t o th e drag of thei r elements; practically to those of collision and engine failure. absence of rotation in the slipstream ; constancy Thu s from (9) and (7) th e final expression for ηr Discussing alternative means for landing in fog, h e of pressure, and velocity over each cross-section of becomes decides in favou r of th e automatic method, in which th e slipstream. These sweeping simplifications need a hanging weight on contact with the ground no t be excused, for i t is familiar to wha t advantage throw s the craft into a phugoid oscillation, a t th e Froud e employed them. The argument is eased b y botto m of which safe landing is effected without a comparing the actual airscrew as fitted to the specially designed undercarriage. In the dis­ aircraft with an imaginary one, displaced well cussion following, it was agreed that all transport upstream , so a s t o b e remove d from interference b y pilots should be required to prove ability to fly th e craft. The disc-area of th e imaginar y actuator blind, as is alread y the case in th e K.L.M. is adjusted to give a slipstream identical in every respect with that of th e rea l one. I n a paper on th e problem s of ai r transpor t from leaving only v an d S, to b e determined . In process th e pilot's point of view, Capt. Macmillan, noticing Dealing first with the upstream airscrew, and of this, however, whether model experiment is tha t every other accident in America has been writin g v for th e outflow, V for th e flight speed, corrected or sheer calculation relied upon, Herr traced to piloting errors, an d bearing in mind th e m for th e "mass-flow," and T for th e thrust , by Helmbold sees no alternativ e but t o pu t t o engineer­ stringent medical supervision in licence renewals, Froude' s theory ing use th e methods of hydrodynamical theory as stresses the poin t tha t in no othe r profession is th e advocate d on general grounds some months ago in physical fitness bar so pronounced. Consequent AIRCRAFT ENGINEERING. The formula (10) shows retiremen t at a comparatively early age suggests a th e overall advantage theoretically obtainable from V ) is th e efficiency of th e airscre w itself, uncorrected • need for th e provision of superannuation employ­ (a) large or multiple airscrews; (i) reduction of for additional aircraft drag due t o its slipstream. ment . He is furthe r concerned with th e professional aircraft drag in th e slipstream ; (c) location of th e T gives also th e tensio n in th e shaft , but thi s is no t statu s of pilots, and t o this and hi s othe r end calls airscrews in regions of accelerated airspeed, as, for tru e of th e actua l case, when th e tensio n F exceeds for the institutio n of a university degree in aviation example, above a wing, giving negative values t o v. th e thrust T by a balanced axial reaction D resembling that of Bachelor of Commerce in Wit h regard t o (b), th e Townend ring, for instance, between airscrew and aeroplane. The rea l actuator anothe r sphere. In a spirited discussion that should be used. There is no need here to give an —disc-area S and inflow v —works in a velocity a a followed, a gradual progress of conditions on accoun t of Mr. Townend's paper, but a note by field found by superposing on th e flight speed an d aircraft towards those on boar d ship was assumed— M. Koning an d Dr. v. d. Maas describes experiments modified inflow an axial component of velocity v affecting the heart of the question of super­ du e t o th e aircraft . We shal l assume v t o be in th e on rings fitted to a nacelle with and withou t an annuation . Institution of an aviation degree wa s airscrew in place. Improvement due t o the ring upstrea m direction. The work done per sec. b y recommended, but rathe r to secure proper training was found t o be reduced by th e airscrew . Investiga­ th e airscrew is F(V—v), and b y th e engine is of new pilots than to confer a doubtful (because tion of th e cause was inconclusive, but it seemed junior) qualification on a man of fifty about to clear that the ring affected the airscrew, while change his employment . turbulenc e in th e slipstream disturbed the action so tha t the efficiency of th e airscre w itself is of th e ring . A group of papers deal with various aspects of stability. Dr. v . d. Maas opens with a timely plea As practical comment on (a), a s also in other for collaboration between test-pilot, designer and connections, Mr. Pierson's brief but valuable Bu t the energy lost in th e slipstream is th e same mathematicia n to remove a "mas s of misunder­ analysis of th e case for th e geared engine (Vol. 2), an d the thrus t is th e same as with the imaginary standings " and so to pave the way for further will prove interesting. Examining a 500 h.p. single- airscrew. So η = η, giving improvemen t of flying qualities. His paper is of a engined freight carrier, Mr. Pierson finds that interest as a full-scale investigation of a simple gearing down from 1800 t o 1100 r.p.m . results in aspec t of longitudinal stability. Herr Hubner 10 per cent more speed, nearly SO per cent better describes the improved flying qualities an d greater climb and ceiling, 14 per cent more economical These ratios clearly equal Therefore safety secured by the general introduction of a cruising, and muc h better take-off. certain measure of statical stability about all thre e Some discussion naturally centred in discrepan­ axes of German aeroplanes for al l position s assumed cies between theory and experiment regarding b y the C.G. The measure of stability desirable choice between tractor and pusher arrangements, Ther e remains to tak e account of th e increase D, is investigated. M. Haus gives an account of th e result of which was t o claim an inherent aero­ of th e dra g of aircraft parts in th e slipstream . Herr his analysis of spins into different categories and dynamica l advantage for the pusher airscrew so Helmbold expresses this in terms if a "resisting refers t o various experiments that have been made, long as it was specially designed. area " S, b y th e relation : D = S · ½p[(V + v )2— V2]. particularl y to those a t Farnborough on th e Bristol 8 8 o Besides Mr. Fedden's paper on air-cooled com­ An alternative expression for th e wor k done by th e Fighter. The group is complete d by Prof. Fukatsu's pression ignition engines, already reported in graphical representation of equilibrium in steady AIRCRAFT ENGINEERING, there is a note on th e same engine is N — ½m [(V + v)— I'2], so tha t spinning. In th e discussion, M. Kjellson described subject from M. Clerget. Papers by Drs. Meissner an d Brenner deal with heat treatment and corrosion or, using (2), of light metals. Vol. 2 is largely concerned with * Report of the Fifth International Congress on air Navigation, The Hague, 1930. (Mattinus Nijhoff. The Hague. £3) legal an d medical matters. F ma y no w b e writte n out a s follows, D repre- http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Aircraft Engineering and Aerospace Technology Emerald Publishing

The Fifth Air Congress

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Abstract

220 AIRCRAFT ENGINEERING September, 1931 Th e Report of th e Paper s Read and Discussions Durin g the Proceeding s at the Hague Reviewed by Dr . N. A. V. Piercy some interesting Swedish tests on spinning to senting the whole glider-drag of th e craft, and a last Th e two volumes recording the work of the destruction (with the aid of a parachute). The ter m being added to include climbing a t vertical Congress together run t o some 1,700 pages. The accoun t is wort h study. As a result it is proposed presentatio n is good, and several lecturers have velocity w. On all counts , then, t o introduce a fourth control, a "spin-rudder," graciously met ou r peculiar national difficulty by giving their papers in English. The summarie s in designed to create pitching moments when the tail Frenc h are also a great help. sideslips. Several papers bear directly upon the ever- Many of th e contribution s have already appeared urgen t question of airscrew body interference. in AIRCRAFT ENGINEERING, amongst these being So th e overall efficiency is Mr. Lock gives an ordered survey of the well- Sir Richard Glazebrook's account of aeronautical known, long and careful research which he an d research in England ; Mr. Relf's description of th e other s have conducted under the wing of the new variable density tunnel; Major Green's dis­ Aeronautical Research Committee. Herr Helmbold cussion of th e use of steel in aircraft ; and Messrs. where sets aside much of th e intricat e detail tha t we have Mitchell and Clifton's analysis of tank tests on grown accustomed to, an d develops the work of T o eliminate the outflow remaining in (8), from floats. It is propose d here t o refer t o a few papers Froude . Some indication of his reasoning and th e two expressions for N: of practical interest which may no t be so widely results should prove generally useful as a basis for known. exploitation in troublesome circumstances. Vol. 1 includes several papers on radio, lighting, an d other general matters essential to traffic. Mr. Helmbol d on Airscrew Theory or, writing k for Capon, on flying and landing in fog, mentions H e proceeds on th e following assumptions: An various new devices which have narrowed risks in airscrew with an infinite number of blades giving giving blind-flying, except - in mountainous country, negligible torqu e a s du e t o th e drag of thei r elements; practically to those of collision and engine failure. absence of rotation in the slipstream ; constancy Thu s from (9) and (7) th e final expression for ηr Discussing alternative means for landing in fog, h e of pressure, and velocity over each cross-section of becomes decides in favou r of th e automatic method, in which th e slipstream. These sweeping simplifications need a hanging weight on contact with the ground no t be excused, for i t is familiar to wha t advantage throw s the craft into a phugoid oscillation, a t th e Froud e employed them. The argument is eased b y botto m of which safe landing is effected without a comparing the actual airscrew as fitted to the specially designed undercarriage. In the dis­ aircraft with an imaginary one, displaced well cussion following, it was agreed that all transport upstream , so a s t o b e remove d from interference b y pilots should be required to prove ability to fly th e craft. The disc-area of th e imaginar y actuator blind, as is alread y the case in th e K.L.M. is adjusted to give a slipstream identical in every respect with that of th e rea l one. I n a paper on th e problem s of ai r transpor t from leaving only v an d S, to b e determined . In process th e pilot's point of view, Capt. Macmillan, noticing Dealing first with the upstream airscrew, and of this, however, whether model experiment is tha t every other accident in America has been writin g v for th e outflow, V for th e flight speed, corrected or sheer calculation relied upon, Herr traced to piloting errors, an d bearing in mind th e m for th e "mass-flow," and T for th e thrust , by Helmbold sees no alternativ e but t o pu t t o engineer­ stringent medical supervision in licence renewals, Froude' s theory ing use th e methods of hydrodynamical theory as stresses the poin t tha t in no othe r profession is th e advocate d on general grounds some months ago in physical fitness bar so pronounced. Consequent AIRCRAFT ENGINEERING. The formula (10) shows retiremen t at a comparatively early age suggests a th e overall advantage theoretically obtainable from V ) is th e efficiency of th e airscre w itself, uncorrected • need for th e provision of superannuation employ­ (a) large or multiple airscrews; (i) reduction of for additional aircraft drag due t o its slipstream. ment . He is furthe r concerned with th e professional aircraft drag in th e slipstream ; (c) location of th e T gives also th e tensio n in th e shaft , but thi s is no t statu s of pilots, and t o this and hi s othe r end calls airscrews in regions of accelerated airspeed, as, for tru e of th e actua l case, when th e tensio n F exceeds for the institutio n of a university degree in aviation example, above a wing, giving negative values t o v. th e thrust T by a balanced axial reaction D resembling that of Bachelor of Commerce in Wit h regard t o (b), th e Townend ring, for instance, between airscrew and aeroplane. The rea l actuator anothe r sphere. In a spirited discussion that should be used. There is no need here to give an —disc-area S and inflow v —works in a velocity a a followed, a gradual progress of conditions on accoun t of Mr. Townend's paper, but a note by field found by superposing on th e flight speed an d aircraft towards those on boar d ship was assumed— M. Koning an d Dr. v. d. Maas describes experiments modified inflow an axial component of velocity v affecting the heart of the question of super­ du e t o th e aircraft . We shal l assume v t o be in th e on rings fitted to a nacelle with and withou t an annuation . Institution of an aviation degree wa s airscrew in place. Improvement due t o the ring upstrea m direction. The work done per sec. b y recommended, but rathe r to secure proper training was found t o be reduced by th e airscrew . Investiga­ th e airscrew is F(V—v), and b y th e engine is of new pilots than to confer a doubtful (because tion of th e cause was inconclusive, but it seemed junior) qualification on a man of fifty about to clear that the ring affected the airscrew, while change his employment . turbulenc e in th e slipstream disturbed the action so tha t the efficiency of th e airscre w itself is of th e ring . A group of papers deal with various aspects of stability. Dr. v . d. Maas opens with a timely plea As practical comment on (a), a s also in other for collaboration between test-pilot, designer and connections, Mr. Pierson's brief but valuable Bu t the energy lost in th e slipstream is th e same mathematicia n to remove a "mas s of misunder­ analysis of th e case for th e geared engine (Vol. 2), an d the thrus t is th e same as with the imaginary standings " and so to pave the way for further will prove interesting. Examining a 500 h.p. single- airscrew. So η = η, giving improvemen t of flying qualities. His paper is of a engined freight carrier, Mr. Pierson finds that interest as a full-scale investigation of a simple gearing down from 1800 t o 1100 r.p.m . results in aspec t of longitudinal stability. Herr Hubner 10 per cent more speed, nearly SO per cent better describes the improved flying qualities an d greater climb and ceiling, 14 per cent more economical These ratios clearly equal Therefore safety secured by the general introduction of a cruising, and muc h better take-off. certain measure of statical stability about all thre e Some discussion naturally centred in discrepan­ axes of German aeroplanes for al l position s assumed cies between theory and experiment regarding b y the C.G. The measure of stability desirable choice between tractor and pusher arrangements, Ther e remains to tak e account of th e increase D, is investigated. M. Haus gives an account of th e result of which was t o claim an inherent aero­ of th e dra g of aircraft parts in th e slipstream . Herr his analysis of spins into different categories and dynamica l advantage for the pusher airscrew so Helmbold expresses this in terms if a "resisting refers t o various experiments that have been made, long as it was specially designed. area " S, b y th e relation : D = S · ½p[(V + v )2— V2]. particularl y to those a t Farnborough on th e Bristol 8 8 o Besides Mr. Fedden's paper on air-cooled com­ An alternative expression for th e wor k done by th e Fighter. The group is complete d by Prof. Fukatsu's pression ignition engines, already reported in graphical representation of equilibrium in steady AIRCRAFT ENGINEERING, there is a note on th e same engine is N — ½m [(V + v)— I'2], so tha t spinning. In th e discussion, M. Kjellson described subject from M. Clerget. Papers by Drs. Meissner an d Brenner deal with heat treatment and corrosion or, using (2), of light metals. Vol. 2 is largely concerned with * Report of the Fifth International Congress on air Navigation, The Hague, 1930. (Mattinus Nijhoff. The Hague. £3) legal an d medical matters. F ma y no w b e writte n out a s follows, D repre-

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Aircraft Engineering and Aerospace Technology – Emerald Publishing

Published: Sep 1, 1931

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