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LIGHT 29 August 1958

wingisprobably basedon anumberofsparsandintegrally stiffened, machined skin panels. Thewings (and possibly thenose)of the aircraft arearranged to fold for carrier stowage.It seems logical to suppose that, although theNA.39 carriesan elevator surface, thewhole tail-plane-elevator group is normally locked to forma slab control. Theelevatorisprobably unlockedto serveas afollow-upandtrimming surface whenthe undercarriage is lowered. For anaircraft thesize of the NA.39 there is at present a limitingdeck-landing speedin theregionof 130 kt,whichis dictatedby thestrengthof theavailable arrester,gear. Moreover, the aircraft must during theapproach haveamarginofsome30 percent overthe unaccelerated stalling speed inordertoallowproper control and manoeuvring dictatedby themirror landing-aid. Boundary-layer control willprobably allow this marginto bereducedtosome-thing like 10-per cent. In order to obtain maxi-mum blowing, full engine power is probablyapplied and very effective drag devices areneededtocounterac t excess thru st. Th is accountsin partfor thesizeof the tail-mounted airbrakes.Thereis no firm indication that the leading edgeofthewingcan becamberedfor theapproach.It isreported thatthe U.S.Navyisinvestigat-ing the possibility of adopting the NA.39 as astrike aircraft; and it isworth notinginthiscon-text that the NA.39 differs radically in its mis-sion profile from theNorth AmericanA3J. Thelatter machineis designed tocruiseat supersonicspeedsat high altitudesand to descend to lowerlevels only during the immediate attack phase;but, liketheNA.39,it carriesacrewof two andsearch radar, and has internal stowagefor wea-pons. The A3J is, however, a good deal largerthan the NA.39, being designed for operationfromForrestal classcarriers. Such extensive deckspace and handling capacity is, of course, notavailablein anyBritish ca rrier.The NA.39isundoubtedly intendedforopera-tion from carriers the sizeof H.M.S . Victorious.Very little information has yet been officiallyreleased, but a study by the Technical Editorappeared in Flight for May 9. The prototypemade its first flight from R.A.E., Bedford, onApril30 in thehandsof Derek Whitehead. 1O7A It has been known for a year ormore that Blackburn and General Aircraft,makersof theBeverley transpon in service withthe Royal Air Force Transport Command, wereworking on the design of a turboprop develop-ment of this aircraft. Tog ether with otherpro-jects, this Beverley developmentthe B.107Aisthesubject of close examinationby theBritishGovernm ent, whose objectis togive effect to thepolicy outlined in the Defence White Paperof1957 the Central Reserve[i.e. theBritish A rmyan d its heavy fighting equipment] must possessthe meansof rapid mobility.

Blackburn's objectivesindesigningtheB.107A,which is powered by four Rolls-Royce Tynes,were to provide in oneaircraft the combinationof short-field performance and parachute-drop-ping capability with the speed and range neces-sary for long-range strategic transport. TheBeverley fulfills the first of these requirements,butnot thesecond.Operating from a typical airfield, the B.107Ais designed tocarry a payload of40,000lb for adistanceof2,550n.m. at 310 kt. Themaximumpayload of 58,0001b can be carried 1300 n.m.,whilst fuel capacity permits a maximum stagedistanceof4,400n.m. On thescoreoffieldper-formance,the 107A canoperateoff 2,400-2,700ftstrips witha 30,0001bpayloadandfuelfor 1,600n.m.Main loading doorsareforward; rear doorscanbe operatedinflightforparachute dropping. Thewingandempennageareexisting B everley u nits,a factor which should ensure considerable econo-mies in development timeandexpenditure.The fuselage has a total volume available forfreight or passengers of 12,883 cu ft. The mainfreight floor is 12ft 6inwide,and has an overallstrength of 250Ib/sq ft; local loadings of 3,600lb / sq ft can be accepted. Pressurization is pro-vided, the maximum differential pressure being6.5lb / sqin. e v e r l e y C I Thr ee squadrons of thistypeare inservice withtheR.A.F.andhave doneexcellent work in many partsof theworld. Par-ticularly valuableis the C.l'sabilityto lift heavyand bulky loads from small fields. Vehicles,equipment or partly dismantled aircraft can betransported; and a load of 29,000 lb has beensuccessfully parachuted with eight G.Q. 66ftparachutes. Troops can be carried in the tailboomandparatrooperscanjum p either from thiscabin or from the main hold. The Beverley ispowered by four Bristol Centaurus pistonengines.

Blackburn B 107 (drawing and artist simpression above).Powerplant ... Four Rolls-Royce TyneSpan 166ft 8inLength U4ftGross weight 175,000 IbCruising speed 350 m.p.h.

lackburn everley C1 photographbelow)Powerplant Four Bristol Centaurus 173Span 162ftLength 99ft SinGross weight 135,000 IbCruising speed 175 m.p.h.