History of aicraft piston engines

F urther improvements in piston engines would have

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Unformatted text preview: t o current minimum values of less than 0.40. This improvement has been a chieved partly through improved design and partly because improved fuels have allowed higher compression ratios (from about 4.0 in 1903 to p resent values, up to 8.0. Best weight per horsepower in 1903 was that of the Manly engine, a t 2.6 lb/hp. This figure was reduced to 1 in 1935 and has gone slightly b elow that since (see table 1). O ne of the most remarkable improvements has been in reliability and r educed maintenance. The very early aircraft engines were overhauled after every flight. The approved overhaul period for the best modern t ransport piston engines is now as high as 2,600 hours. F urther improvements in piston engines would have been made had it n ot been for the introduction of turboprop and turbojet engines, which v irtually put an end to intensive development of the large piston engine. J et engines are also used for certain categories of small aircraft. F igure 72 shows the piston-engine family as it has developed, finally c ulminating in the V-12 liquid-cooled engines as represented by the R olls-Royce and Packard Merlin, and the 18-cylinder air-cooled radials, b y the Pratt & Whitney R-2800 and the Wright 3350, of which the 85 AIRCRAFT ENGINE P ISTON- S PARK S TEAK LIQUID H BNSON-STR.INS F ELLOW GIFFAW* (MAXIMA LANGLEY IN-LINE COOLED RAD I A L VEA S CHWARTZ i e 9 7 * U A f c o H N i u e ) OU M OWT |S38*(TI<ICWCL« («() iEpPELJH I JOO* ( I V I I T M ' » M « » > BESLtR I903 WRICHT (MAKLV) CLBM.MT* I904 A tTTOlNETTEVs CAST-IROW CVLS i9to t l/R.Tli* H ALL * coTT OtT^OIT P ANHAKO H OTTA MAY BACH r-i t a c E t t i AUSTWJ-"0»lML'tk 1915- • unvnoti STBCL C VL. H6A"OSr^ E.NV. C UT5T1S4-V8 (C.I. C YLINOE«.ll W ELDED STEEL CYHNPgttS CLEMENT SALMS0Ml9le-IB| MERCEDES A LUMINUM i 'PA l»0TTA A N*ALOO HALL SCOTT rrc. UP..EPT.Y:!; NAPIER. •LION' l<J20 HEADS . t CURTISS l Ay/RAHCE 3-CYL K-ia CURTISS C-12 LAWRANCE H C URTISS p-1.3. VVRl&MT 'T' WRISHT I 92r WRICHT X-3 X-4B C U R T I S S C 0NQUER0UK-R KESTREL •WRIOWT J - 5 £ ? W i VoRLNBT W R l f r H T R-IB20 BRISTOL J U P I T E R ' 1930 M O D E L EMCIWCS I - C YLINDER. AlR COOLED R-ROYCG * R." 1^35 G NOME-RHONE A L L I S O N V -1710 JUNKERS O.t-l.W. NAKAJIMA W R I & H T R-ZfcOO MITSUBISHI PACKARD YTRIGHT 3 3 5 0 B R I S T O L H ERCULES (SLllVt.-»ALVm) I 940 JWERLW 1945 ^35i5t5£~J55£E^2!HL£25£ 1950 N OTES O NLY S IGNIFICANT EN&IUES IMCLUP»D D ATE5 BEFORE ig 10 A RE Fon. R U T A FTER 1)10 PATE l i S C H i H L , UiK SUCCESSFUL. rufiuT OH T Y . F S - T E I T C OMPLETION P ATKS AMP 0HT>»R I N o avCS , A P P R O T U K A T C I'JS'S' " L l f t H T E E - T »AM-AIR. PARCMTHIiSlS = X>ID HOT C.KTAYLOR FLY F EB.ig*2 Ff'aure 7 2 19^0 86 F AMILY TREE IGNITION All? IN COOLED LINE ANO YfiE O PPOSED r*AN ROTARV ( •»•. LIMIT FLAMEtl ( BALZER') (LANtLtX) M A N L Y 'A SCALE igor f * 6 A M J P AHWU.I.) C URTISS V -B RENAULTv-a GNOME ( ESNAULT- P ELTEEle") ANZANKtcYL) ANZANI RADIALS I9J0 L E R.HOUE...
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