FlightGlobal.com
Home
Premium
Archive
Video
Images
Forum
Atlas
Blogs
Jobs
Shop
RSS
Email Newsletters
You are in:
Home
Aviation History
1951
1951 - 0010.PDF
FLIGHT, 4 January 1951 COMPARATIVE DATA ON AUTOMATIC GUNS Type Browning (Brit, re-design) t Vickers K Gorman MG.8I Rheinmetall-Borsig MG.I7 U.S. BrowningOerlikon F.F Hispmo Mk. V Mauser MG.IS 1/20 Mauser MG.213/20 Rheinmetall-Borsig M.K. 108 Mauser MG.2I3/C Vickers-Colt type 1932 • ... M.K.2I4/A M.K.II2 M.K.4I2 M.K.114 M.K.2I4/B M.K.IIS Calibre (mm) 77 7.7 7.92 , 7-92 12.720 20 20 20 30 30 37 50 55 55 5S 55 55 Operation recoil-operated; mech- anically locked breech gas-operatedditto. recoil operated; mech- anically locked breech dittoditto (with free blow- back) ditto ditto gas-operated recoil-operated with free blow-backgas-operated. recoil-operated with mechanically locked breech automatically actuated charging cradle. gas-operated ditto ditto, ditto recoilless (venturi- relief) . Weapon Weight (Ib) 22 19.514 28 5253 105 98 165 132 166 200 1,060 600 398 1,550 1,430 395 Weapon LengthOverall (in) 44.5 — 47.2 5852 8 81 80 — 41.5 63 77 163 79 — — — — Muzzle Velocity (ft/sec) 2,660 2,4002,450 2,450 2,5001,930 2,750 2,600 3,300 1,650 1.750 1,950 2,750 2,000 2,140 3,300 — 2,000 Rate of Fire (rds/min) 1,200 950-1,2001,200-1,500 1,100 850 520 6C0 6E0 I.2C0 650 1,100 100 145 300 — ieo 180 300 Projectile Weight (oz) 0.344 0.3440.45 0.45 1.74.82 4.25 5.35 7.4 116 11.6 23.5 53.5 52.4 52.4 63.5 63.5 54.4 Remarks Beit-fed. Drum-fed. Belc-fed. Belt-fed." Mine "shell with 0.69 ozH E. charge. Splinter shell. No remote cocking. Made in 95 working hours (mass pro- duction) ; also produced with 15 mm calibre (muzzle velocity 3,150ft/sec). Extra-long " mine " shell with 0.9 oz H.E. charge. " Mine " shell with 3 oz H.E. charge. Made in 75 working hours.To replace M.K. 108. - ) As installed in Perth flying boats. i Adapted tank gun. " Mine "shell witn 12.3 oz H.E. charge. For 1,000 yd combat range. " Mine " shell with 14.8 oz H.E. charge.Parallel development to M.K.I 12. For 2,000 yd combat range, with semi- rigid mounting. " Mine " shell with 16 oz H.E. charge.Parallel development to M.K.I 14. Combustible cartridge case. Develop- ment not completed. FIGHTER ARMAMENT. . . or cloud interception could be anywhere near effectual.Such a device, too, will bring some welcome relief from the growing ammunition loads which the intercepter aircraft iscompelled to carry. Designs for instruments of this kind exist, but the writer is doubtful whether they are approach-ing operational use by any of the Western Powers According to German assessment, 50 per cent probabilityof destruction couldHbe expected from a two 30 mm M.K. 108 gun installation firing over 700 yards' range at flight-pathangles up to 30 deg, provided that the EZ/42 gyro-sight was "used. The assumption is an aggregated rate of fire of 60'Jrounds/min lasting three seconds, and a muzzle velocity of 1,870 ft/sec, i.e., the expenditure of 20 shells, with fourdirect hits effecting the destruction. Without gyro-sight, equal probability can be predicted when fire is opened over450 yards only. Hence, an automatic sight is an excellent protection for the intercepter, besides giving better chancesof success. Weight and Bulk.—In piston-engined intcrcepters a lowarmament-installation weight is of primary importance, but the space required does not matter a great deal. Jet androcket intercepters, however, present "logistic" armament problems: they are more susceptible to bulk than to weight,Hjles, blisters, or protruding barrels are no longer tolerated. Then there are the problems of facilitating armament ser-vicing and re-arming, both of which are operationally vital: the higher the target's speed and altitude, the smaller thetime interval available between alert and interception. Standing intercepter patrols may no longer be considered a-tactical error of the First World War. Servicing and re- arming, therefore, dominate the practical usefulness of anintercepter aircraft. As has been said, the large-calibre gun is necessarily longand needs much ammunition space. In jet-fighter design the fuselage nose is easily occupied by four guns of, say,55 mm calibre; the cockpit may even have to be shifted back (decreasing the field of vision), and no space may beleft for radar equipment. Moreover, the recoil loads may have a disturbing effect 'upon automatic detection, rangingand firing devices. Even 20 mm guns can produce vibra-" tions causing distressing consequences for airframe andaccessories. Moreover, the fuselage nose is better employed to house the pilot, especially if he is to be in the proneattitude. Finally, the best place for a refuelling "probe" is undoubtedly at the fuselage nose. Wing installation of guns no longer seems a practical pro-position: modern jet intercepters have thin wings, and these are sensitive against shock loads from recoil. Wing roots, too, are generally occupied by air intakes and /or dischargeducts. Also an eccentric installation of heavier-calibre guns presents potential danger if one of the weapons jams. One may safely predict that in future intercepters thefuselage nose will no longer be available to house a gun installation, apart from the fact that the structuralsystem will be unfavourable to it. These reasons make it desirable to replace guns by some other form of armament,and one with which the aircraft designer can do better. Rockets produce no recoil, and, if they are small enough,they can be stored anywhere and be launched from any • place. Although economical aspects claim only minor attentionin a struggle for the survival of a nation, intercepter arma- ment claims consideration in this respect. Costs of equip-ment and, in particular, armament, form rather formidable items, yet the actual operation life of such an aircraft isamazingly short. During the last war, the average flying life was 40 to 50 flying hours (more than double the averagelife of a fighter during the First World War); an increase to, say, 400 flying hours is hoped for with very modern types-—of vastly higher initial cost. A simplified armament, con- sisting in effect of little more than the missiles to be fired,will thus be beneficial from the point of reducing labour, saving material and lowering final cost. In maintenance,too, rocket missiles of the R.4/M type will score. Estimating formula; have been worked out, on the basisof experimental data, to assess quantitatively the calibre influence upon weapon property and performance; and simi-lar formula; established for supersonic rocket missiles allow us to compare automatic shell-guns with such missiles. Quan-titatively, the investigation leads to the conclusion that the advantages of rockets, in all respects, are too great to beoverlooked. (To be concluded) A LOWERING PRODUCTION COSTS T the annual general meeting of Joseph Lucas, Ltd , SirPeter Bennett, O.B.E., J.P., M.P. explained how the com- pany was endeavouring to reduce selling costs by a continuousprogramme of reducing all manufacturing costs that came under its control. The manufacturing time set for any product was treated asits index of controllable cost and compared with the time set by American manufacturers for a corresponding product. Whenthe volume of production was similar, as in the case of aircraft equipment, the variation between the British and U.S. times wasnegligible; in car equipment, the American production of which was very much greater, the comparison showed an appreciable(though narrowing) gap. *"
Sign up to
Flight Digital Magazine
Flight Print Magazine
Airline Business Magazine
E-newsletters
RSS
Events
