Hi, I like messing around with the LAA's preliminary design spreadsheets available here -- http://www.lightaircraftassociation.co.uk/2010/Engineering/Design/preliminary_design.html -- but I am dubious of some of the numbers. The completed sample spreadsheet used these numbers for prop efficiency and drag:
Cheers,
Matthew
- Propeller efficiency at take-off 70%
- Propeller efficiency in the climb 75%
- Propeller efficiency in the cruise 85%
- Cd (profile) 0.01
- Cd (parasite) 0.015 (Speeds between 1.1 Vs and 2.7 Vs)
Cheers,
Matthew