Fig. 1.
![Changes in the power [hp] of aircraft engines in the period 1903–1918 [7, 12, 15, 26, 29,30,31, 33,34,35,36,37,38,39,40,41,42].](https://sciendo-parsed.s3.eu-central-1.amazonaws.com/67f6ed7c8d1bec042eaca24e/j_tar-2025-0001_fig_001.jpg?X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Content-Sha256=UNSIGNED-PAYLOAD&X-Amz-Credential=AKIA6AP2G7AKOUXAVR44%2F20251205%2Feu-central-1%2Fs3%2Faws4_request&X-Amz-Date=20251205T175425Z&X-Amz-Expires=3600&X-Amz-Signature=29d17ca9bebc45064d5b64639618c2b4b134b08cf23d7a5ab6470bb7f887d8a4&X-Amz-SignedHeaders=host&x-amz-checksum-mode=ENABLED&x-id=GetObject)
Fig. 2.
![Changes in the ratio of aircraft engines’ power to their weight [hp/kg] in the period 1903–1918 [7, 12, 15, 26, 29,30,31, 33,34,35,36,37,38,39,40,41,42].](https://sciendo-parsed.s3.eu-central-1.amazonaws.com/67f6ed7c8d1bec042eaca24e/j_tar-2025-0001_fig_002.jpg?X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Content-Sha256=UNSIGNED-PAYLOAD&X-Amz-Credential=AKIA6AP2G7AKOUXAVR44%2F20251205%2Feu-central-1%2Fs3%2Faws4_request&X-Amz-Date=20251205T175425Z&X-Amz-Expires=3600&X-Amz-Signature=ce39c88a9103732dc7f30087e4b3ee9b5848a7f29b08d9842e2a0ac937fde07b&X-Amz-SignedHeaders=host&x-amz-checksum-mode=ENABLED&x-id=GetObject)
Fig. 3.
![Changes in the ratio of aircraft engines’ power to their displacement volume [hp/dm3] in the period 1903–1918 [7, 12, 15, 26, 29,30,31, 33,34,35,36,37,38,39,40,41,42].](https://sciendo-parsed.s3.eu-central-1.amazonaws.com/67f6ed7c8d1bec042eaca24e/j_tar-2025-0001_fig_003.jpg?X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Content-Sha256=UNSIGNED-PAYLOAD&X-Amz-Credential=AKIA6AP2G7AKOUXAVR44%2F20251205%2Feu-central-1%2Fs3%2Faws4_request&X-Amz-Date=20251205T175425Z&X-Amz-Expires=3600&X-Amz-Signature=1a5d2f15c940de8ae7d352f17de4acd7d510ebb83813f5c0f9360879fcd3f1fa&X-Amz-SignedHeaders=host&x-amz-checksum-mode=ENABLED&x-id=GetObject)
Fig. 4.
![Changes in maximum revolutions per minute of the crankshaft [rpm] of aircraft engines in the period 1903–1918 [7, 12, 15, 26, 29,30,31, 33,34,35,36,37,38,39,40,41,42].](https://sciendo-parsed.s3.eu-central-1.amazonaws.com/67f6ed7c8d1bec042eaca24e/j_tar-2025-0001_fig_004.jpg?X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Content-Sha256=UNSIGNED-PAYLOAD&X-Amz-Credential=AKIA6AP2G7AKOUXAVR44%2F20251205%2Feu-central-1%2Fs3%2Faws4_request&X-Amz-Date=20251205T175425Z&X-Amz-Expires=3600&X-Amz-Signature=7666613f915d7da9da5c8b17c8fb8851aae5df664069b79e10dded5f399fe4ce&X-Amz-SignedHeaders=host&x-amz-checksum-mode=ENABLED&x-id=GetObject)
Fig. 5.
![Changes in power [hp] of radial and inline engines in the period 1903–1918 [7, 12, 15, 26, 29,30,31, 33,34,35,36,37,38,39,40,41,42].](https://sciendo-parsed.s3.eu-central-1.amazonaws.com/67f6ed7c8d1bec042eaca24e/j_tar-2025-0001_fig_005.jpg?X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Content-Sha256=UNSIGNED-PAYLOAD&X-Amz-Credential=AKIA6AP2G7AKOUXAVR44%2F20251205%2Feu-central-1%2Fs3%2Faws4_request&X-Amz-Date=20251205T175425Z&X-Amz-Expires=3600&X-Amz-Signature=5c52c476b5df15decea5f6509dd441bb03bb1131a28d0e1b1cb945a40c1e10b4&X-Amz-SignedHeaders=host&x-amz-checksum-mode=ENABLED&x-id=GetObject)
Fig. 6.
![Changes in the ratio of radial and inline engines to their displacement volume [hp/dm3] in the period 1903–1918 [7, 12, 15, 26, 29,30,31, 33,34,35,36,37,38,39,40,41,42].](https://sciendo-parsed.s3.eu-central-1.amazonaws.com/67f6ed7c8d1bec042eaca24e/j_tar-2025-0001_fig_006.jpg?X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Content-Sha256=UNSIGNED-PAYLOAD&X-Amz-Credential=AKIA6AP2G7AKOUXAVR44%2F20251205%2Feu-central-1%2Fs3%2Faws4_request&X-Amz-Date=20251205T175425Z&X-Amz-Expires=3600&X-Amz-Signature=7c5c518ba61a9f69910c6780d84af6138b15c9517390c8e23a55d818370c97ac&X-Amz-SignedHeaders=host&x-amz-checksum-mode=ENABLED&x-id=GetObject)
Fig. 7.
![Changes in the ratio of radial and inline engines’ power to their weight [hp/kg] in the period 1903–1918 [7, 12, 15, 26, 29,30,31, 33,34,35,36,37,38,39,40,41,42].](https://sciendo-parsed.s3.eu-central-1.amazonaws.com/67f6ed7c8d1bec042eaca24e/j_tar-2025-0001_fig_007.jpg?X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Content-Sha256=UNSIGNED-PAYLOAD&X-Amz-Credential=AKIA6AP2G7AKOUXAVR44%2F20251205%2Feu-central-1%2Fs3%2Faws4_request&X-Amz-Date=20251205T175425Z&X-Amz-Expires=3600&X-Amz-Signature=ff4310a730e892ecd60795935b1a2181956fdb225f9aedff9af02ed38fb66604&X-Amz-SignedHeaders=host&x-amz-checksum-mode=ENABLED&x-id=GetObject)
Fig. 8.
![Changes in power [hp] of aircraft engines in the period 1918–1939 [1,2,3,4, 10– 13,14,15,16,17, 27,28,29,30,31, 49, 51, 54,55,56,57,58,59,60,61,62,63,64,65,66,67,68].](https://sciendo-parsed.s3.eu-central-1.amazonaws.com/67f6ed7c8d1bec042eaca24e/j_tar-2025-0001_fig_008.jpg?X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Content-Sha256=UNSIGNED-PAYLOAD&X-Amz-Credential=AKIA6AP2G7AKOUXAVR44%2F20251205%2Feu-central-1%2Fs3%2Faws4_request&X-Amz-Date=20251205T175425Z&X-Amz-Expires=3600&X-Amz-Signature=9d0300ed4fb7c903b51e36a9eeb7af2b1b6067b521dbf41a05ef0e6899f4d89f&X-Amz-SignedHeaders=host&x-amz-checksum-mode=ENABLED&x-id=GetObject)
Fig. 9.
![Changes in the ratio of aircraft engines’ power to their weight [hp/kg] in the period 1918–1939 [1,2,3,4, 10, 13,14,15,16,17, 27,28,29,30,31, 49, 51, 54,55,56,57,58,59,60,61,62,63,64,65,66,67,68].](https://sciendo-parsed.s3.eu-central-1.amazonaws.com/67f6ed7c8d1bec042eaca24e/j_tar-2025-0001_fig_009.jpg?X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Content-Sha256=UNSIGNED-PAYLOAD&X-Amz-Credential=AKIA6AP2G7AKOUXAVR44%2F20251205%2Feu-central-1%2Fs3%2Faws4_request&X-Amz-Date=20251205T175425Z&X-Amz-Expires=3600&X-Amz-Signature=5c69c42ca9be7e879b76723784a4a53f9e120ea9bd75bbe181aa878730572969&X-Amz-SignedHeaders=host&x-amz-checksum-mode=ENABLED&x-id=GetObject)
Fig. 10.
![Changes in the ratio of aircraft engines’ power to their displacement volume [hp/dm3] in the period 1918–1939 [1,2,3,4, 10, 13,14,15,16,17, 27,28,29,30,31, 49, 51, 54,55,56,57,58,59,60,61,62,63,64,65,66,67,68].](https://sciendo-parsed.s3.eu-central-1.amazonaws.com/67f6ed7c8d1bec042eaca24e/j_tar-2025-0001_fig_010.jpg?X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Content-Sha256=UNSIGNED-PAYLOAD&X-Amz-Credential=AKIA6AP2G7AKOUXAVR44%2F20251205%2Feu-central-1%2Fs3%2Faws4_request&X-Amz-Date=20251205T175425Z&X-Amz-Expires=3600&X-Amz-Signature=33cf2253da2938e842f8fc79534b6ce715183ac1088f8d50a06188e0eef70e2c&X-Amz-SignedHeaders=host&x-amz-checksum-mode=ENABLED&x-id=GetObject)
Fig. 11.
![Changes in maximum revolutions per minute of the crankshaft [rpm] of aircraft engines in the period 1918–1939 [1,2,3,4, 10, 13,14,15,16,17, 27,28,29,30,31, 49, 51, 54,55,56,57,58,59,60,61,62,63,64,65,66,67,68].](https://sciendo-parsed.s3.eu-central-1.amazonaws.com/67f6ed7c8d1bec042eaca24e/j_tar-2025-0001_fig_011.jpg?X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Content-Sha256=UNSIGNED-PAYLOAD&X-Amz-Credential=AKIA6AP2G7AKOUXAVR44%2F20251205%2Feu-central-1%2Fs3%2Faws4_request&X-Amz-Date=20251205T175425Z&X-Amz-Expires=3600&X-Amz-Signature=d114ec6fb3b3490d1c88e51d0e60186caf4c71ed5329e2c3e4fc48be138b4c74&X-Amz-SignedHeaders=host&x-amz-checksum-mode=ENABLED&x-id=GetObject)
Fig. 12.
![Changes in power [hp] of radial and inline engines in the period 1918–1939 [1,2,3,4, 10, 13,14,15,16,17, 27,28,29,30,31, 49, 51, 54,55,56,57,58,59,60,61,62,63,64,65,66,67,68].](https://sciendo-parsed.s3.eu-central-1.amazonaws.com/67f6ed7c8d1bec042eaca24e/j_tar-2025-0001_fig_012.jpg?X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Content-Sha256=UNSIGNED-PAYLOAD&X-Amz-Credential=AKIA6AP2G7AKOUXAVR44%2F20251205%2Feu-central-1%2Fs3%2Faws4_request&X-Amz-Date=20251205T175425Z&X-Amz-Expires=3600&X-Amz-Signature=4c534930c90a508d2a5b0eff926630190e152c470d87231fb546f981cd0b3460&X-Amz-SignedHeaders=host&x-amz-checksum-mode=ENABLED&x-id=GetObject)
Fig. 13.
![Changes in the ratio of radial and inline engines’ power to their weight [hp/kg] in the period 1918–1939 [1,2,3,4, 10, 13,14,15,16,17, 27,28,29,30,31, 49, 51, 54,55,56,57,58,59,60,61,62,63,64,65,66,67,68].](https://sciendo-parsed.s3.eu-central-1.amazonaws.com/67f6ed7c8d1bec042eaca24e/j_tar-2025-0001_fig_013.jpg?X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Content-Sha256=UNSIGNED-PAYLOAD&X-Amz-Credential=AKIA6AP2G7AKOUXAVR44%2F20251205%2Feu-central-1%2Fs3%2Faws4_request&X-Amz-Date=20251205T175425Z&X-Amz-Expires=3600&X-Amz-Signature=3c249678a48b83080c17e1e5091a2d44bab7a00f8dda04bceb56fb3153f0cf27&X-Amz-SignedHeaders=host&x-amz-checksum-mode=ENABLED&x-id=GetObject)
Fig. 14.
![Changes in the ratio of radial and inline engines to their displacement volume [hp/dm3] in the period 1918–1939 [1,2,3,4, 10, 13,14,15,16,17, 27,28,29,30,31, 49, 51, 54,55,56,57,58,59,60,61,62,63,64,65,66,67,68].](https://sciendo-parsed.s3.eu-central-1.amazonaws.com/67f6ed7c8d1bec042eaca24e/j_tar-2025-0001_fig_014.jpg?X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Content-Sha256=UNSIGNED-PAYLOAD&X-Amz-Credential=AKIA6AP2G7AKOUXAVR44%2F20251205%2Feu-central-1%2Fs3%2Faws4_request&X-Amz-Date=20251205T175425Z&X-Amz-Expires=3600&X-Amz-Signature=2cffaf33e4cc9c8c690716df79f60c9ff349898ec6a0da5a64d07c6f2469ee3e&X-Amz-SignedHeaders=host&x-amz-checksum-mode=ENABLED&x-id=GetObject)
Fig. 15.
![Changes in maximum revolutions per minute of the crankshaft [rpm] of radial and inline engines in the period 1918–1939 [1,2,3,4, 10, 13,14,15,16,17, 27,28,29,30,31, 49, 51, 54,55,56,57,58,59,60,61,62,63,64,65,66,67,68].](https://sciendo-parsed.s3.eu-central-1.amazonaws.com/67f6ed7c8d1bec042eaca24e/j_tar-2025-0001_fig_015.jpg?X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Content-Sha256=UNSIGNED-PAYLOAD&X-Amz-Credential=AKIA6AP2G7AKOUXAVR44%2F20251205%2Feu-central-1%2Fs3%2Faws4_request&X-Amz-Date=20251205T175425Z&X-Amz-Expires=3600&X-Amz-Signature=df9226fe3023335552598d2978a9f5e3f523612a4e626c128f5591dc6778dd05&X-Amz-SignedHeaders=host&x-amz-checksum-mode=ENABLED&x-id=GetObject)
Fig. 16.
![Changes in power [hp] of aircraft engines in the period 1939–1945 [1,2,3,4,5, 14, 17, 21, 24, 28, 29, 45, 49,50,51,52, 58, 66,67,68,69,70, 73,74,75,76,77,78,79,80,81,82,83,84,85,86,87,88,89].](https://sciendo-parsed.s3.eu-central-1.amazonaws.com/67f6ed7c8d1bec042eaca24e/j_tar-2025-0001_fig_016.jpg?X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Content-Sha256=UNSIGNED-PAYLOAD&X-Amz-Credential=AKIA6AP2G7AKOUXAVR44%2F20251205%2Feu-central-1%2Fs3%2Faws4_request&X-Amz-Date=20251205T175425Z&X-Amz-Expires=3600&X-Amz-Signature=46b978272364abbe76eabc6d19fde4809ccd2426e8fc5d9a93996a4ad292c458&X-Amz-SignedHeaders=host&x-amz-checksum-mode=ENABLED&x-id=GetObject)
Fig. 17.
![Changes in the ratio of aircraft engines’ power to their weight [hp/kg] in the period 1939–1945 [1,2,3,4,5, 14, 17, 21, 24, 28, 29, 45, 49,50,51,52, 58, 66,67,68,69,70, 73,74,75,76,77,78,79,80,81,82,83,84,85,86,87,88,89].](https://sciendo-parsed.s3.eu-central-1.amazonaws.com/67f6ed7c8d1bec042eaca24e/j_tar-2025-0001_fig_017.jpg?X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Content-Sha256=UNSIGNED-PAYLOAD&X-Amz-Credential=AKIA6AP2G7AKOUXAVR44%2F20251205%2Feu-central-1%2Fs3%2Faws4_request&X-Amz-Date=20251205T175425Z&X-Amz-Expires=3600&X-Amz-Signature=6615ba66e7dd30748a9b5fce91dca568d2c43fb946287dd7b30f16307ff01498&X-Amz-SignedHeaders=host&x-amz-checksum-mode=ENABLED&x-id=GetObject)
Fig. 18.
![Changes in the ratio of aircraft engines’ power to their displacement volume [hp/dm3] 1939–1945 [1,2,3,4,5, 14, 17, 21, 24, 28, 29, 45, 49,50,51,52, 58, 66,67,68,69,70, 73,74,75,76,77,78,79,80,81,82,83,84,85,86,87,88,89].](https://sciendo-parsed.s3.eu-central-1.amazonaws.com/67f6ed7c8d1bec042eaca24e/j_tar-2025-0001_fig_018.jpg?X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Content-Sha256=UNSIGNED-PAYLOAD&X-Amz-Credential=AKIA6AP2G7AKOUXAVR44%2F20251205%2Feu-central-1%2Fs3%2Faws4_request&X-Amz-Date=20251205T175425Z&X-Amz-Expires=3600&X-Amz-Signature=4926db174346f00420271316980539140c84b352b9f90083f5c67c08f29a0e20&X-Amz-SignedHeaders=host&x-amz-checksum-mode=ENABLED&x-id=GetObject)
Fig. 19.
![Changes in maximum revolutions per minute of the crankshaft [rpm] of aircraft engines in the period 1939–1945 [1,2,3,4,5, 14, 17, 21, 24, 28, 29, 45, 49,50,51,52, 58, 66,67,68,69,70, 73,74,75,76,77,78,79,80,81,82,83,84,85,86,87,88,89].](https://sciendo-parsed.s3.eu-central-1.amazonaws.com/67f6ed7c8d1bec042eaca24e/j_tar-2025-0001_fig_019.jpg?X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Content-Sha256=UNSIGNED-PAYLOAD&X-Amz-Credential=AKIA6AP2G7AKOUXAVR44%2F20251205%2Feu-central-1%2Fs3%2Faws4_request&X-Amz-Date=20251205T175425Z&X-Amz-Expires=3600&X-Amz-Signature=db1573b4dc1970e0313f9bc61bdee4bec45c653629a80079baa0d6f05aae5c01&X-Amz-SignedHeaders=host&x-amz-checksum-mode=ENABLED&x-id=GetObject)
Fig. 20.
![Changes in power [hp] of radial and inline engines in the period 1939–1945 [1,2,3,4,5, 14, 17, 21, 24, 28, 29, 45, 49,50,51,52, 58, 66,67,68,69,70, 73,74,75,76,77,78,79,80,81,82,83,84,85,86,87,88,89].](https://sciendo-parsed.s3.eu-central-1.amazonaws.com/67f6ed7c8d1bec042eaca24e/j_tar-2025-0001_fig_020.jpg?X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Content-Sha256=UNSIGNED-PAYLOAD&X-Amz-Credential=AKIA6AP2G7AKOUXAVR44%2F20251205%2Feu-central-1%2Fs3%2Faws4_request&X-Amz-Date=20251205T175425Z&X-Amz-Expires=3600&X-Amz-Signature=920d53eab0f40d28d36b5b7744c3e73e8dfa41f43da2aebdcb615fddf5b9eb43&X-Amz-SignedHeaders=host&x-amz-checksum-mode=ENABLED&x-id=GetObject)
Fig. 21.
![Changes in the ratio of radial and inline engines to their displacement volume [hp/dm3] in the period 1939–1945 [1,2,3,4,5, 14, 17, 21, 24, 28, 29, 45, 49,50,51,52, 58, 66,67,68,69,70, 73,74,75,76,77,78,79,80,81,82,83,84,85,86,87,88,89].](https://sciendo-parsed.s3.eu-central-1.amazonaws.com/67f6ed7c8d1bec042eaca24e/j_tar-2025-0001_fig_021.jpg?X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Content-Sha256=UNSIGNED-PAYLOAD&X-Amz-Credential=AKIA6AP2G7AKOUXAVR44%2F20251205%2Feu-central-1%2Fs3%2Faws4_request&X-Amz-Date=20251205T175425Z&X-Amz-Expires=3600&X-Amz-Signature=c143d0193ab48fbe2871bcce49119c691eb6024f5554a057d246684efd484b88&X-Amz-SignedHeaders=host&x-amz-checksum-mode=ENABLED&x-id=GetObject)
Fig. 22.
![Changes in the ratio of radial and inline engines’ power to their weight [hp/kg] in the period 1939–1945 [1,2,3,4,5, 14, 17, 21, 24, 28, 29, 45, 49,50,51,52, 58, 66,67,68,69,70, 73,74,75,76,77,78,79,80,81,82,83,84,85,86,87,88,89].](https://sciendo-parsed.s3.eu-central-1.amazonaws.com/67f6ed7c8d1bec042eaca24e/j_tar-2025-0001_fig_022.jpg?X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Content-Sha256=UNSIGNED-PAYLOAD&X-Amz-Credential=AKIA6AP2G7AKOUXAVR44%2F20251205%2Feu-central-1%2Fs3%2Faws4_request&X-Amz-Date=20251205T175425Z&X-Amz-Expires=3600&X-Amz-Signature=685509029d5f57c0459dc595d71767b0caf9a24d04d6d4172b295d113bcbc241&X-Amz-SignedHeaders=host&x-amz-checksum-mode=ENABLED&x-id=GetObject)
Fig. 23.
![Changes in maximum revolutions per minute of the crankshaft [rpm] of radial and inline engines in the period 1939–1945 [1,2,3,4,5, 14, 17, 21, 24, 28, 29, 45, 49,50,51,52, 58, 66,67,68,69,70, 73,74,75,76,77,78,79,80,81,82,83,84,85,86,87,88,89].](https://sciendo-parsed.s3.eu-central-1.amazonaws.com/67f6ed7c8d1bec042eaca24e/j_tar-2025-0001_fig_023.jpg?X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Content-Sha256=UNSIGNED-PAYLOAD&X-Amz-Credential=AKIA6AP2G7AKOUXAVR44%2F20251205%2Feu-central-1%2Fs3%2Faws4_request&X-Amz-Date=20251205T175425Z&X-Amz-Expires=3600&X-Amz-Signature=e6360cfbb01d72e31b9bd4a3e57110857918d98936e58e0de877c3c2cd701a99&X-Amz-SignedHeaders=host&x-amz-checksum-mode=ENABLED&x-id=GetObject)
Fig. 24.
![Changes in power [hp] of aircraft engines in the years 1903–1945 [1,2,3,4,5, 7, 10, 12,13,14,15,16,17, 21, 24, 26,27,28,29,30,31, 33,34,35,36,37,38,39,40,41,42, 45, 49,50,51,52, 54,55,56,57,58,59,60,61,62,63,64,65,66,67,68,69,70, 73,74,75,76,77,78,79,80,81,82,83,84,85,86,87,88,89].](https://sciendo-parsed.s3.eu-central-1.amazonaws.com/67f6ed7c8d1bec042eaca24e/j_tar-2025-0001_fig_024.jpg?X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Content-Sha256=UNSIGNED-PAYLOAD&X-Amz-Credential=AKIA6AP2G7AKOUXAVR44%2F20251205%2Feu-central-1%2Fs3%2Faws4_request&X-Amz-Date=20251205T175425Z&X-Amz-Expires=3600&X-Amz-Signature=3d5141ac86d7d77417f31e91d1ed9da7d3b0c2fa7fa78db43f788302781f1c86&X-Amz-SignedHeaders=host&x-amz-checksum-mode=ENABLED&x-id=GetObject)
Fig. 25.
![Changes in the ratio of aircraft engines’ power to their displacement volume [hp/dm3] in the years 1903–1945 [1,2,3,4,5, 7, 10, 12,13,14,15,16,17, 21, 24, 26,27,28,29,30,31, 33,34,35,36,37,38,39,40,41,42, 45, 49,50,51,52, 54,55,56,57,58,59,60,61,62,63,64,65,66,67,68,69,70, 73,74,75,76,77,78,79,80,81,82,83,84,85,86,87,88,89].](https://sciendo-parsed.s3.eu-central-1.amazonaws.com/67f6ed7c8d1bec042eaca24e/j_tar-2025-0001_fig_025.jpg?X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Content-Sha256=UNSIGNED-PAYLOAD&X-Amz-Credential=AKIA6AP2G7AKOUXAVR44%2F20251205%2Feu-central-1%2Fs3%2Faws4_request&X-Amz-Date=20251205T175425Z&X-Amz-Expires=3600&X-Amz-Signature=ab3cf420c1e08d0e115288796151bc491e8bb51eaa23fbfa8acbdf1e8579aba8&X-Amz-SignedHeaders=host&x-amz-checksum-mode=ENABLED&x-id=GetObject)
Comparison of the Manly-Balzer and Wright Flyer I engines [1, 14, 16, 19–20]_
| Name | Manly-Balzer | Wright Flyer I |
|---|---|---|
| Power [hp] | 52 | 16 |
| Weight [kg] | 62 | 81.4 |
| Displacement [dm3] | 8.85 | 3.28 |
| Revolutions per minute [rpm] | 950 | 1025 |
| Power-to-weight ratio [hp/kg] | 0.839 | 0.197 |
| Power-to-displacement ratio [hp/dm3] | 5.876 | 4.878 |
| Weight of 1 dm3 of displacement [kg/dm3] | 7.006 | 24.817 |