MotOpinion - Untitled
591ft above Sea Level, 29,92inHg, 59°F
Motor: BP A2212-13; 1000rpm/V; 0,5A no-load; 0,09 Ohms.
Battery: Kokam 360SHD (20C); 2 cells; 360mAh @ 3,7V; 0,0688 Ohms/cell.
Speed Control: Generic Brushless ESC; 0,006 Ohms; High rate.
Drive System: Generic 8x4,5in Prop; 8x4,5 (Pconst=1,31; Tconst=0,95) direct drive.
Airframe: Go-Go Dancer; 295sq.in; 11,2oz RTF; 5,5oz/sq.ft; Cd=0,05; Cl=0,44; Clopt=0,54; Clmax=1,11.
Stats: 41 W/lb in; 34 W/lb out; 11mph stall; 16mph opt @ 78% (17:40, 72°F); 18mph level @ 84% (16:11, 73°F); 358ft/min @ 14,3°; -155ft/min @ -6,1°.
Possible Power System Problems:
The full-throttle motor current at the best lift-to-drag ratio airspeed (3,4A) is lower than the motor's maximum efficiency current (6,2A). A higher current level would improve system efficiency.
Current can be increased by using more cells, a larger diameter or higher pitched propeller, a lower gear ratio, or some combination of these methods.
Possible Aerodynamic Problems:
The static pitch speed (27mph) is less than 2,5 times the stall speed (11mph), which may result in reduced performance at typical flying speeds and a low maximum speed. This situation is usually acceptable for an electric sailplane or other slow-flying model.
Pitch speed can be increased by using a higher pitched and/or smaller diameter propeller, a higher cell count, or some combination of these methods.
With a wing loading of 5,5oz/sq.ft, a model of this size will have very sedate flying characteristics. It will be suitable for relaxed flying, in calm or very light wind conditions.
The static thrust (7,1oz) to weight (11,2oz) ratio is 0,63:1, which will result in short take-off runs, and no difficulty taking off from grass surfaces (assuming sufficiently large wheels).
At the best lift-to-drag ratio airspeed, the excess-thrust (2,6oz) to weight (11,2oz) ratio is 0,24:1, which will give good climbs and acceleration. This is a good in-flight thrust to weight ratio for a basic trainer.
This analysis is based on calculations that take motor heating effects into account.
These calculations are based on mathematical models that may not account for all limitations of the components used. Always consult the power system component manufacturers to ensure that no limits (current, rpm, etc.) are being exceeded.