261:
17:
32:(USAAC) to develop a high-performance aircraft engine that would be equal to or better than the aircraft and engines then under development in Europe. The project goal was to produce an engine that was capable of delivering 1 hp/in (46 kW/L) of engine displacement for a weight of less than 1 lb/hp delivered. The ultimate design goal was an increased
323:
The fighter aircraft procurement program for FY 1940 was contained in a document that was approved by
Assistant Secretary of War Louis K. Johnson on 9 June 1939. That document was the "Request for Data R40-C", and unlike previous aircraft procurement requests, it was sent to only a limited number of
245:
A second cylinder was added to Hyper No. 1 to make a horizontal opposed engine for evaluation of an horizontal opposed 12-cylinder engine. After running the modified engine with different combinations of cylinder bore and stroke, it was found that the high coolant temperature required to maintain the
89:
is a combination of energy and the rate it is delivered, so to improve the power-to-weight ratio, one would need to increase the operating pressures of the engine, the operating speed, or a combination of both. Further gains could be made by eliminating losses like friction, combustion inefficiencies
284:
and later, an inverted V-12 engine before becoming reliable enough to be considered for full production as the
Continental IV-1430 in 1943. By then other engines had already passed its 1,600 hp (1,200 kW) rating, and although the IV-1430 had a better power-to-weight ratio, there was little
51:
radial, developed about 1,200 hp (895 kW) from 1,830 in (30 L) so an advance of at least 50% would be needed. Simply scaling up an existing design would not solve the problem. While it would have increased the total available power, it would also increase the weight, and thus not
152:
The USAAC was not so convinced that the sleeve valve was the only solution. Ironically it was one of
Ricardo's papers on the sleeve valve design that led to the USAAC's hyper engine efforts. In one late 1920s paper he claimed that the 1 hp/in³ goal was impossible to achieve with poppet valve
97:
The USAAC engineers determined that it would study all three improvements. Before long, they concluded that increasing the combustion temperature and scavenging efficiency promised the greatest increases of all of the possibilities. To meet that goal, increasing engine speed seemed to be the most
315:
Although the XP-38 was able to fly at speeds in excess of 413 mph, its twin engines and relatively large frame meant it was large and heavy. This, in turn, meant the XP-38 was not as maneuverable as most single-engine fighters. The XP-38 also had a newly introduced liquid-cooled engine, the
113:
from inconsistent detonation. Uncontrolled, knock can damage the engine and was a major block on the way to improved power settings. This change would also increase the operating temperatures, which presented a problem with the valves. Valves were already reaching temperatures that would cause
271:
The Army apparently became concerned about the development of a suitable supercharger for high-altitude use, and for further development in 1934 they asked for a newer cylinder with slightly less performance and an increased volume of 118.8 in from its 5.5 in (140 mm) bore and
279:
Another change was to the engine layout. The Army, convinced that future aircraft designs would use engines buried in the wings for additional streamlining, asked
Continental to design a full-sized flat-horizontally opposed engine for installation inside a wing. The resulting engine was the
122:". Valve float allows gases in the cylinder to escape through the partially open valve, reducing the engine efficiency. Increasing valve spring pressure to close the valves faster led to rapid cam wear and increased friction, reducing overall performance by more than any horsepower gained.
84:
was being introduced in place of steel as the quality and strength of aluminum alloys improved during the 1930s; this lowered engine weight noticeably, but not enough to achieve a 50% overall improvement. To reach that goal, the power of the engine would also need to be increased.
414:
formance engines. The submitted designs were graded using a "Figure of merit" (FOM) rating system, and then, using the FOM results (which ranged from 444.12 for the
Allison V-1710-E8 to 817.90 for the Pratt and Whitney X-1800-A4G), they were separated into one of three groups.
272:
5.0 in (130 mm) stroke. This size cylinder would then be used in a 1,425 in 12-cylinder engine, delivering the same 1,000 hp, with a performance of 0.7 hp/in. This placed its performance on a par with newer experimental engines from Europe like the
246:
required output was impractical. A third high-performance single-cylinder engine was then constructed with lower operating parameters. This engine was designated "Hyper No. 2", and became the test bed for developing the cylinders that would become the O-1430-1.
55:
Several engines were built as part of the hyper program, but for a variety of reasons none of these saw production use. Air-cooled engines from a variety of US companies were delivering similar power ratings by the early 1940s, and the licensed production of the
153:
type engines. The USAAC engineering team at Wright Field decided to test this claim by beating it. They proposed an engine of about 1200 cubic inches (20 L), hoping the engine's smaller size would lead to reduced
422:
Those placed in the third group proposed using an engine that was unlikely to be developed into flying condition by the time the airframe was ready to fly. They were not considered to be viable in the time frame
117:
Increasing operational speed is also, theoretically, a simple change to the engine design. However, at high operating speeds the valves do not completely close before the cam opens them again, a problem called
406:
A total of 26 designs, with a mix of 16 engine models from six engine companies, were submitted by seven of the selected companies. These engines became known as the "Hyper
Engines", a contraction of
222:
is used — the sodium liquefies and considerably increases the heat transfer from the valve's head to its stem and then to the relatively cooler cylinder head where the liquid coolant picks it up.
320:. The Allison's in-line vee cylinder arrangement allowed for a narrow aerodynamic shape that had less drag than the air-cooled radial engine fighters that predominated in America at the time.
188:, and the coolant temperature to 300 °F (149 °C) before reaching the magic numbers. By 1932, the USAAC's encouraging efforts led the Army to sign a development contract with
288:
The project was eventually guided by the requirements in the "Request for data R40-C", which was included as a part of the
Financial Year (FY) 1940 aircraft procurement program.
192:
for the continued development of the engine design. The contract limited
Continental's role to construction and testing, leaving the actual engineering development to the Army.
39:
At the time, no production engine could come close to the requirements, although this milestone had been met by specially modified or purpose-built racing engines such as the
426:
The remaining ten designs were placed in the second group: those that were an advancement in aeronautical engineering, with an engine that would be ready to fly, when needed.
237:
of the glycol (about 2/3 that of water). They eventually determined that a 50/50 mixture (by volume) of water and glycol provided optimal heat removal.
1072:
296:
As 1938 came to an end, war in Europe was imminent. At this point, European aircraft had greatly surpassed US designs. The two top USAAC fighters, the
994:
233:, which would allow temperatures up to 280 °F. At first they proposed using 100% glycol, but there was little improvement due to the lower
265:
125:
As valves were a key issue in both approaches to improved performance, they had been a major area of research in the 1920s and 30s. In the UK,
419:
Those placed in the first group were little more than modifications to existing designs. They were not considered to be sufficiently advanced.
373:
After final review and approval as Air Corps Type
Specification XC-622, a further four manufacturers were added to the distribution:
229:
at that time used plain water, which limited operating temperatures to about 180 °F (82 °C). The engineers proposed using
133:
system for exactly these reasons, claiming it was the only way forward. He had some success in selling this idea, most notably to
585:
Three additional high-performance engines were considered for the USAAC's FY 1942 "Hyper" engine procurement program. They were:
430:
Only three of these ten designs were approved, and contracts were made for a limited prototype run of three aircraft for each.
180:, Farnborough, started working on the problem with a single-cylinder test engine that he converted to liquid cooling, using a
1080:
969:
763:
771:
48:
203:
from 5 in to 4.62 in, creating the 84 in³ cylinder. This would be used in a V-12 engine of 1008 in³
226:
1099:
1048:
1011:
796:'s advanced medium bomber program that used similar high-output aviation powerplants of over 1,500 kW output apiece.
98:
attractive solution. However, there were a number of practical problems that were impeding progress in these areas.
398:
These companies had only ten days to agree to the terms of the document, and only 30 days to submit their designs.
280:
Continental O-1430, which would require a ten-year development period which changed the layout to first an upright
52:
have any significant effect on the power-to-weight ratio. To meet the goals, more radical changes were needed.
981:
Effects of
Additions of Aromatics on Knocking Characteristics of Several 100-octane Fuels at Two Engine Speeds
774:, all surpassed the USAAC requirements, and continue flying into the 21st century, primarily flying restored
449:
76:
Improvements in construction and lighter materials had already delivered some benefits on the way to higher
767:
29:
460:
699:
595:
189:
1119:
554:
529:
464:
442:
134:
755:
In the end, all of these programs were canceled, and the surviving engines became museum pieces.
309:
212:
185:
106:
215:
efficiency. Continental's first test engine, the single-cylinder Hyper No.1, first ran in 1933.
218:
They eventually determined that exhaust valves could run cooler when a hollow core filled with
177:
308:
they would be completely outclassed. One of America’s answers to this issue, the twin-engined
333:
77:
33:
392:
352:
305:
199:
from 7 in to 5 in in order to allow higher engine speeds, and then decreased the
169:
68:
did the same from a US design, one produced as a private effort outside the hyper program.
8:
504:
453:
204:
154:
988:
382:
273:
255:
57:
1095:
1076:
1044:
1007:
965:
357:
301:
208:
102:
158:
674:
607:
377:
367:
230:
196:
146:
110:
86:
759:
646:
600:
338:
317:
285:
else to suggest setting up production in the middle of the war was worthwhile.
219:
65:
61:
1113:
724:
589:
437:
Vultee Aircraft's Model 70 Alternate 2, (FOM score: 817.9), which became the
328:
297:
234:
211:
to operate multiple valves of smaller size, which would improve charging and
200:
142:
126:
44:
276:, at least when running on the higher-octane fuels the Army planned to use.
448:
Curtiss-Wright St Louis' Model P248C, (FOM score: 770.6), which became the
438:
304:, were just able to hit 300 mph (480 km/h). Against the 340+ mph
181:
173:
130:
1094:. Phoenix Mill, Gloucestershire, England, UK: Sutton Publishing Limited.
119:
40:
979:
Biermann, Arnold E, Corrington, Lester C. and Harries, Myron L. (1942).
281:
138:
90:
and scavenging losses, delivering more of the theoretical power to the
176:
and a former colleague of Ricardo while Heron had been working at the
793:
260:
91:
758:
Ironically, engines that were not considered under the program; the
788:
652:
81:
1023:
Development of Aircraft Engines and Development of Aviation Fuels
775:
347:
324:
aircraft manufacturers. The original document was to be sent to:
16:
387:
362:
363:
Vought-Sikorsky Aircraft Division, United Aircraft Corporation
20:
Liberty L-12 engine, from which Hyper Engine No.1 was derived
983:. Cleveland, Ohio, May: Aircraft Engine Research Laboratory.
368:
Vultee Aircraft Division, Aviation Manufacturing Corporation
459:
Northrop's Model N2-B (FOM score: 725.8), which became the
433:
The three aircraft/engine combinations that were selected:
64:
provided hyper-like performance from an inline while the
1069:
The Engines of Pratt & Whitney: A Technical History
344:
Curtiss-Wright Corporation, St. Louis Airplane Division
184:
engine cylinder. He pushed the power to 480 psi
195:
Starting with the L-12-cylinder, they decreased the
141:
became "a believer". Ricardo's friendly competitor,
1073:American Institute of Aeronautics and Astronautics
114:pre-ignition of the fuel as it flowed past them.
1111:
1092:World Encyclopedia of Aero Engines, 5th Edition
962:American Secret Pusher Fighters of World War II
36:suitable for long-range airliners and bombers.
266:National Museum of the United States Air Force
249:
606:Not to be left out, the US Navy selected the
993:: CS1 maint: multiple names: authors list (
145:, designed his own sleeve valve engine with
1032:Aircraft Propulsion, Smithsonian Press, GPO
941:
939:
937:
935:
933:
878:
876:
866:
864:
862:
860:
149:, another prominent British engine maker.
1004:Major Piston Aero Engines of World War II
903:
312:, was entering an extended test program.
291:
71:
47:. A typical large engine of the era, the
978:
930:
921:
912:
614:The high-performance engines of FY 1941
472:The high-performance engines of FY 1940
348:Grumman Aircraft Engineering Corporation
259:
129:had written an influential paper on the
15:
1089:
1066:
1001:
873:
857:
848:
821:
812:
1112:
1029:
959:
885:
839:
764:Pratt & Whitney R-2800 Double Wasp
1041:Allied Piston Engines of World War II
1038:
1020:
894:
830:
772:Pratt & Whitney R-4360 Wasp Major
105:is an easy change that improves the
49:Pratt & Whitney R-1830 Twin Wasp
13:
1059:
1021:Schlaifer, Robert and Herron S.D.
14:
1131:
334:Consolidated Aircraft Corporation
28:was a 1930s study project by the
610:for funding in FY 1942 as well.
515:1,600 hp at 3,200 rpm
952:
679:24-cylinder horizontal opposed
393:Northrop Aircraft, Incorporated
750:
741:2,400 lb (1,100 kg)
716:3,250 lb (1,470 kg)
691:2,430 lb (1,100 kg)
666:2,600 lb (1,200 kg)
555:Pratt & Whitney X-1800-A4G
530:Pratt & Whitney X-1800-A3G
465:Pratt & Whitney X-1800-A3G
443:Pratt & Whitney X-1800-A4G
1:
800:
450:Curtiss-Wright XP-55 Ascender
358:Republic Aviation Corporation
353:Lockheed Aircraft Corporation
240:
186:Brake Mean Effective Pressure
164:
768:Wright R-3350 Duplex-Cyclone
612:
470:
30:United States Army Air Corps
7:
1030:Taylor, C. Fayette (1971).
781:
700:Pratt & Whitney XH-3130
461:Northrop XP-56 Black Bullet
378:Hughes Aircraft Corporation
250:Continental O/V/IV/XIV-1430
10:
1136:
960:Balzer, Gerald H. (2008).
617:
596:Pratt & Whitney H-3130
580:
475:
401:
383:McDonnell Aircraft Company
339:Curtiss-Wright Corporation
253:
190:Continental Motors Company
341:Curtiss Airplane Division
329:Bell Aircraft Corporation
172:, head of development at
135:Bristol Aeroplane Company
1002:Bingham, Victor (1998).
805:
827:Biermann pp 16, 17
388:Boeing Aircraft Company
207:. They used the L-12's
107:mean effective pressure
1090:Gunston, Bill (2006).
1067:Connors, Jack (2010).
1039:White, Graham (1995).
1006:. Airlife Publishing.
292:Request for data R40-C
268:
178:Royal Aircraft Factory
78:power-to-weight ratios
72:Design and development
21:
1043:. SAE International.
1025:. Harvard University.
505:Continental IV-1430-3
454:Continental IV-1430-3
263:
34:power-to-weight ratio
19:
1071:. Reston. Virginia:
704:24-cylinder H-block
559:24-cylinder H-block
534:24 cylinder H-block
306:Messerschmitt Bf 109
109:(MEP), but leads to
964:. Specialty Press.
729:42-cylinder 7-bank
615:
473:
157:and hence improved
613:
471:
269:
256:Continental I-1430
58:Rolls-Royce Merlin
22:
1082:978-1-60086-711-8
971:978-1-58007-125-3
748:
747:
738:1.09 hp/in³
657:3,421.2 in³
578:
577:
518:1.12 hp/in³
463:, powered by the
452:, powered by the
441:, powered by the
274:Rolls-Royce PV-12
264:IV-1430-9 in the
209:overhead camshaft
103:compression ratio
1127:
1120:Aircraft engines
1105:
1086:
1054:
1035:
1026:
1017:
998:
992:
984:
975:
946:
943:
928:
925:
919:
916:
910:
907:
901:
898:
892:
889:
883:
882:White p 376
880:
871:
868:
855:
852:
846:
843:
837:
834:
828:
825:
819:
818:White p 211
816:
713:.84 hp/in³
688:.93 hp/in³
675:Lycoming XH-2470
663:.61 hp/in³
616:
608:Lycoming XH-2470
568:.85 hp/in³
543:.85 hp/in³
474:
147:Napier & Son
1135:
1134:
1130:
1129:
1128:
1126:
1125:
1124:
1110:
1109:
1108:
1102:
1083:
1062:
1060:Further reading
1057:
1051:
1014:
986:
985:
972:
955:
950:
949:
944:
931:
926:
922:
917:
913:
909:Schlaifer p 253
908:
904:
900:Balzer pp 9, 10
899:
895:
890:
886:
881:
874:
869:
858:
853:
849:
844:
840:
835:
831:
826:
822:
817:
813:
808:
803:
784:
753:
744:.98 hp/lb
732:2,160 in³
719:.82 hp/lb
707:3,130 in³
694:.96 hp/lb
682:2,470 in³
669:.81 hp/lb
640:
632:
583:
574:.68 hp/lb
562:2,600 in³
549:.68 hp/lb
537:2,600 in³
524:.99 hp/lb
512:1,430 in³
498:
490:
404:
294:
258:
252:
243:
231:ethylene glycol
227:cooling systems
167:
137:Engines, where
111:engine knocking
101:Increasing the
74:
12:
11:
5:
1133:
1123:
1122:
1107:
1106:
1100:
1087:
1081:
1063:
1061:
1058:
1056:
1055:
1049:
1036:
1027:
1018:
1012:
999:
976:
970:
956:
954:
951:
948:
947:
929:
920:
911:
902:
893:
884:
872:
856:
847:
838:
829:
820:
810:
809:
807:
804:
802:
799:
798:
797:
783:
780:
760:Allison V-1710
752:
749:
746:
745:
742:
739:
736:
735:2,350 hp
733:
730:
727:
721:
720:
717:
714:
711:
710:2,650 hp
708:
705:
702:
696:
695:
692:
689:
686:
685:2,300 hp
683:
680:
677:
671:
670:
667:
664:
661:
660:2,100 hp
658:
655:
649:
647:Allison V-3420
643:
642:
637:
634:
629:
626:
623:
622:Configuration
620:
604:
603:
601:Allison V-3420
598:
593:
582:
579:
576:
575:
572:
571:3,250 lb
569:
566:
565:2,200 hp
563:
560:
557:
551:
550:
547:
546:3,250 lb
544:
541:
540:2,200 hp
538:
535:
532:
526:
525:
522:
521:1,615 lb
519:
516:
513:
510:
509:inverted V-12
507:
501:
500:
495:
492:
487:
484:
481:
480:Configuration
478:
469:
468:
457:
446:
428:
427:
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396:
395:
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385:
380:
371:
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336:
331:
318:Allison V-1710
310:Lockheed XP-38
293:
290:
254:Main article:
251:
248:
242:
239:
166:
163:
73:
70:
66:Allison V-1710
62:Packard V-1650
9:
6:
4:
3:
2:
1132:
1121:
1118:
1117:
1115:
1103:
1101:0-7509-4479-X
1097:
1093:
1088:
1084:
1078:
1074:
1070:
1065:
1064:
1052:
1050:1-56091-655-9
1046:
1042:
1037:
1033:
1028:
1024:
1019:
1015:
1013:1-84037-012-2
1009:
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934:
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867:
865:
863:
861:
851:
845:Bingham pg 49
842:
833:
824:
815:
811:
795:
792:, the German
791:
790:
786:
785:
779:
777:
773:
769:
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743:
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734:
731:
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725:Wright R-2160
723:
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641:weight ratio
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625:Displacement
624:
621:
619:Engine model
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590:Wright R-2160
588:
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499:weight ratio
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483:Displacement
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477:Engine model
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302:Curtiss P-36A
299:
298:Seversky P-35
289:
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235:specific heat
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150:
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144:
143:Frank Halford
140:
136:
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128:
127:Harry Ricardo
123:
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115:
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104:
99:
95:
93:
88:
83:
79:
69:
67:
63:
59:
53:
50:
46:
45:Rolls-Royce R
42:
37:
35:
31:
27:
18:
1091:
1068:
1040:
1031:
1022:
1003:
980:
961:
953:Bibliography
923:
914:
905:
896:
887:
850:
841:
832:
823:
814:
787:
757:
754:
651:24-cylinder
605:
584:
439:Vultee XP-54
432:
429:
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407:
405:
397:
372:
322:
314:
295:
287:
278:
270:
244:
224:
217:
205:displacement
194:
182:Liberty L-12
174:Wright Field
168:
151:
131:sleeve valve
124:
116:
100:
96:
75:
54:
38:
26:hyper engine
25:
23:
945:Balzer p.24
927:Balzer p 15
918:Balzer p 13
870:Balzer p.28
854:White p 375
836:Taylor p 64
751:Program end
633:horsepower
628:Horsepower
491:horsepower
486:Horsepower
282:V-12 engine
120:valve float
41:Napier Lion
891:Balzer p 7
801:References
778:aircraft.
241:Hyper No.2
213:scavenging
165:Hyper No.1
139:Roy Fedden
989:cite book
794:Luftwaffe
592:"Tornado"
170:Sam Heron
92:propeller
1114:Category
789:Bomber B
782:See also
653:W engine
639:Power to
631:Specific
497:Power to
489:Specific
423:allowed.
300:and the
82:Aluminum
776:warbird
636:Weight
581:FY 1941
494:Weight
402:FY 1940
225:Liquid
60:as the
1098:
1079:
1047:
1010:
968:
467:engine
456:engine
445:engine
220:sodium
197:stroke
806:Notes
159:range
87:Power
1096:ISBN
1077:ISBN
1045:ISBN
1008:ISBN
995:link
966:ISBN
770:and
201:bore
155:drag
43:and
24:The
412:per
410:gh-
1116::
1075:.
991:}}
987:{{
932:^
875:^
859:^
766:,
762:,
408:Hi
161:.
94:.
80:.
1104:.
1085:.
1053:.
1034:.
1016:.
997:)
974:.
118:"
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