{"action":"created","issue":{"url":"https://api.github.com/repos/Juanvvc/c172p-detailed/issues/273","labels_url":"https://api.github.com/repos/Juanvvc/c172p-detailed/issues/273/labels{/name}","comments_url":"https://api.github.com/repos/Juanvvc/c172p-detailed/issues/273/comments","events_url":"https://api.github.com/repos/Juanvvc/c172p-detailed/issues/273/events","html_url":"https://github.com/Juanvvc/c172p-detailed/issues/273","id":87049958,"number":273,"title":"C172, 180 hp engine: want to test?","user":{"login":"dany93","id":11994061,"avatar_url":"https://avatars.githubusercontent.com/u/11994061?v=3","gravatar_id":"","url":"https://api.github.com/users/dany93","html_url":"https://github.com/dany93","followers_url":"https://api.github.com/users/dany93/followers","following_url":"https://api.github.com/users/dany93/following{/other_user}","gists_url":"https://api.github.com/users/dany93/gists{/gist_id}","starred_url":"https://api.github.com/users/dany93/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/dany93/subscriptions","organizations_url":"https://api.github.com/users/dany93/orgs","repos_url":"https://api.github.com/users/dany93/repos","events_url":"https://api.github.com/users/dany93/events{/privacy}","received_events_url":"https://api.github.com/users/dany93/received_events","type":"User","site_admin":false},"labels":[{"url":"https://api.github.com/repos/Juanvvc/c172p-detailed/labels/FDM","name":"FDM","color":"f7c6c7"},{"url":"https://api.github.com/repos/Juanvvc/c172p-detailed/labels/help%20wanted","name":"help wanted","color":"159818"}],"state":"open","locked":false,"assignee":null,"milestone":{"url":"https://api.github.com/repos/Juanvvc/c172p-detailed/milestones/3","html_url":"https://github.com/Juanvvc/c172p-detailed/milestones/FlightGear%203.8%20feature%20freeze","labels_url":"https://api.github.com/repos/Juanvvc/c172p-detailed/milestones/3/labels","id":1146258,"number":3,"title":"FlightGear 3.8 feature freeze","description":"Deadline for new features.","creator":{"login":"onox","id":3361585,"avatar_url":"https://avatars.githubusercontent.com/u/3361585?v=3","gravatar_id":"","url":"https://api.github.com/users/onox","html_url":"https://github.com/onox","followers_url":"https://api.github.com/users/onox/followers","following_url":"https://api.github.com/users/onox/following{/other_user}","gists_url":"https://api.github.com/users/onox/gists{/gist_id}","starred_url":"https://api.github.com/users/onox/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/onox/subscriptions","organizations_url":"https://api.github.com/users/onox/orgs","repos_url":"https://api.github.com/users/onox/repos","events_url":"https://api.github.com/users/onox/events{/privacy}","received_events_url":"https://api.github.com/users/onox/received_events","type":"User","site_admin":false},"open_issues":27,"closed_issues":0,"state":"open","created_at":"2015-06-02T23:55:57Z","updated_at":"2015-06-18T19:10:35Z","due_on":"2015-12-16T23:00:00Z","closed_at":null},"comments":72,"created_at":"2015-06-10T17:46:28Z","updated_at":"2015-06-20T10:18:55Z","closed_at":null,"body":"As several people noticed, the 160 hp-powered c172p is under-powered, which makes it \"lazy\" at full load. Floats and amphibious worsen everything (added drag).\r\nI tried to fiddle the propeller pitch angle, at no avail. The original one is not far from the best.\r\n\r\nI have a test version with a **180 hp engine**.\r\nOn my c172-180hp branch https://github.com/dany93/c172p-detailed/tree/c172-180hp\r\n\r\n Easy for the engine.\r\n\r\nThe propeller is much more questionable. It is the result of compromise between climbing rate, short field takeoff, and cruise or max velocity.\r\nFor the propeller, I use the NACA 640 data http://naca.central.cranfield.ac.uk/reports/1938/naca-report-640.pdf. They worked rather well for DR400, DC3, Cap10B. But everything is never certain... And I refuse to cheat the values. I check their consistency, I (re-)calculate the efficiency when I extract them from the curves.\r\n\r\n**Positive:**\r\n- With default gear at full load (2400 lb), I have a 830 - 850 ft/mn climbing rate (80 KIAS).\r\n- With amphibious at full load (2400 lb), 648 ft/mn (80 KIAS). In accordance with @tigert's data  https://github.com/Juanvvc/c172p-detailed/issues/269#issuecomment-110268962\r\n\r\n**No so positive:**\r\n- The propeller (76\" diameter) does not reach 2700 RPM, which means that the 180 hp are not reached during climbing. But if I decrease the pitch angle, the max air velocity will be lower than I expect. My attempt with a 78\" diameter propeller makes me feel that it is not the solution (remains to be seen better).\r\n- Levelled flight 2000 ft, 2500 RPM: with standard gears115 KIAS (hardly higher than with 160 hp). With amphibious 110 KIAS (I would have expected less, and do not know what to do).\r\n\r\nMy reasoning is that, even if this propeller is still questionable, the result is better than with the 160 hp engine. More pleasant.\r\n\r\n"},"comment":{"url":"https://api.github.com/repos/Juanvvc/c172p-detailed/issues/comments/113741195","html_url":"https://github.com/Juanvvc/c172p-detailed/issues/273#issuecomment-113741195","issue_url":"https://api.github.com/repos/Juanvvc/c172p-detailed/issues/273","id":113741195,"user":{"login":"onox","id":3361585,"avatar_url":"https://avatars.githubusercontent.com/u/3361585?v=3","gravatar_id":"","url":"https://api.github.com/users/onox","html_url":"https://github.com/onox","followers_url":"https://api.github.com/users/onox/followers","following_url":"https://api.github.com/users/onox/following{/other_user}","gists_url":"https://api.github.com/users/onox/gists{/gist_id}","starred_url":"https://api.github.com/users/onox/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/onox/subscriptions","organizations_url":"https://api.github.com/users/onox/orgs","repos_url":"https://api.github.com/users/onox/repos","events_url":"https://api.github.com/users/onox/events{/privacy}","received_events_url":"https://api.github.com/users/onox/received_events","type":"User","site_admin":false},"created_at":"2015-06-20T10:18:55Z","updated_at":"2015-06-20T10:18:55Z","body":"Ok. Do you see you have brought in the latest stuff from master and then put your own stuff (1 commit) on top of it?"}}