Não são apenas os gêmeos grandes que têm "alta compressão" ou usam turbos. Muitos motores de quatro e seis assentos têm motores de compressão mais altos também sem turbos. Meu Lycoming O-360-A1F6D não tem turbo. possui os cilindros de taxa de compressão 8.5: 1 e precisa do 100LL para impedir a detonação precoce.
https://www.lycoming.com/sites/default/files/O-HO-IO-HIO-AIO%20%26%20TIO-360%20Oper%20Manual%2060297-12.pdf
Série O-360-A
FAA Type Certificate ...................................... 286
Rated horsepower ......................................... 180
Rated speed, RPM.......................................... 2700
Bore, inches.................................................... 5.125
Stroke, inches.................................................. 4.375
Displacement, cubic inches............................. 361.0
Compression ratio .......................................... 8.5:1
(-A1F6D indica coisas como eixo oco para pressão do óleo para acionar a hélice de velocidade constante via governador, contrapesos no cárter para equilibrar os cilindros, magneto duplo versus magnetos separados 2).
E se você olhar a página pdf, a página 42 (marcada como 3-10), quase todos os motores O-360 precisam de combustível de octanagem mais alto:
FUEL AND OIL *Aviation Grade Fuel
Model Series Minimum Grade
O-360-B, -D 80/87
O-360-A1P, -C1F, -C4F; HO-360-C1A 91/96
O-360-C, -F; HO-360-A, -B; IO-360-B, -E; HIO-360-B 91/96 or 100/130
O-360-J2A 91/96 or 100/100LL
IO-360-L2A, -M1A, -M1B 91/96 or 100LL
HIO-360-G1A 91/96 or 100LL
O-360-A, -C1G, -C4P, -A1H6; TIO-360-C1A6D 100/100LL
IO-360-B1G6, -C1G6, -J, -K2A, -A1D6D, -A3B6, -A3D6D;
HIO-360-A1B 100/100LL
AIO-360-A, -B; IO-360-A, -C, -D, -F 100/130
HIO-360-A, -C, -D, -E, -F 100/130
TIO-360-A 100/130
A versão injetada de combustível usada na versão de engrenagem retrátil do meu avião. IO-360Axxx, possui cilindros de maior proporção, 8.7: 1 e desenvolve mais potência em 15-20.
Aqui estão mais algumas informações sobre o combustível da Leaded Aviation, de https://www.faa.gov/about/initiatives/avgas/
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The Federal Aviation Administration (FAA) shares the Environmental Protection Agency's (EPA) concerns about lead emissions from small aircraft. Owners and operators of more than 167,000 piston-engine aircraft operating in the United States rely on aviation gasoline (avgas) to power their aircraft. Avgas is the only remaining lead-containing transportation fuel. Lead in avgas prevents damaging engine knock, or detonation, that can result in a sudden engine failure. Lead is a toxic substance that can be inhaled or absorbed in the bloodstream, and the FAA and EPA and industry are partnering to remove it from avgas. Avgas emissions have become the largest contributor to the relatively low levels of lead emissions produced in this country.
To help "get the lead out," FAA is supporting the research of alternate fuels at our William J. Hughes Technical Center in Atlantic City. We are working with the aircraft and engine manufacturers, fuel producers, the EPA and industry associations to overcome technical and logistical challenges to developing and deploying a new, unleaded fuel.
The FAA continues to work with EPA to make this a smooth transition and to ensure the supply of aviation gasoline is not interrupted, and that all aircraft can continue to fly.
Este artigo de acompanhamento tem mais informações:
The unleaded fuel disaster - what it means for pilots | Air Facts Journal
https://airfactsjournal.com/2018/11/the-unleaded-fuel-disaster-what-it-means-for-pilots/
The new timeline focuses on testing of an unleaded fuel being developed by Shell—now the lone participant in PAFI following the elimination of Swift Fuels’ candidate fuel.
Outro artigo, da AOPA https://www.aopa.org/news-and-media/all-news/2018/october/03/faa-sees-mid-2020-completion-of-unleaded-avgas-project
The FAA had halted testing last spring, calling for Shell and Swift to address concerns that emerged in data gathered in early phase tests.
In August, following a meeting of the PAFI Steering Group at AOPA Headquarters, AOPA reported on PAFI’s continued progress and plans going forward.
Before flight testing under PAFI resumes, preliminary work “will include clearing material compatibility, durability, detonation, and performance issues,” the FAA said.
Addressing the extension of testing into 2020, the FAA reiterated that “the PAFI mission endures,” noting, “although it will take additional time to realize this goal, it is essential to ensure a viable, safe, and economical fuel is ultimately authorized.”
“AOPA is encouraged to see Shell’s continued commitment and efforts to work on issues and come up with mitigations,” said David Oord, AOPA senior director of regulatory affairs. “We and the other members of the PAFI steering group were pleased to see that early results from their efforts look promising.”
Oord reiterated continued support of the government-industry efforts to identify, test, and authorize a general aviation fleetwide unleaded replacement for 100LL avgas, noting AOPA’s longstanding position that the resulting fuel must not require extensive changes to engines, aircraft systems, or fuel delivery systems.
“Ultimately, we are looking for the best fuel, whether it results from PAFI or other means.The goal is the same, regardless of the path we take to get there.”
Lembro-me de ver alguns (ou alguns) artigos durante o desligamento do Gov't do XN XNX de fevereiro, dizendo que os testes foram suspensos por um tempo desconhecido, para que o combustível sem chumbo não fique disponível por um tempo.
Os motores de potência mais alta, como o O-540 e o IO-540, são versões do cilindro 6 do meu motor de cilindro 4. Portanto, se o meu tiver cilindros 180HP / 4, ~ 45 HP / cilindro, um O-540 está gerando ~ 6x45 = 270HP e IO-540 ~ 50 HP / cyl = 300 HP. Eles podem ser encontrados nos aviões com assento 6 e nos gêmeos maiores. Todos temos a mesma necessidade de combustível 100LL. Meu aeroporto doméstico parou de transportar mogas de oitava 87, presumo que a demanda tenha caído e só carregue o 100 LL agora. Eu nem me lembro do último aeroporto em que eu estava que tinha mogas 87.