RE: Brushless Motor questions.
Okay I am liking how this is looking, I will LOSE speed with the formosa, with this setup, BUT looks like it is saying acrobatics will be great! Almost near prop hang! All I have to do is change to the STOCK Formosa 10x6 Prop...
MotOpinion - GWS - Formosa - Hacker B20 18L - 1060 Prop 2.8:1 GWS 350c "A" Gearing gearbox
25ft above Sea Level, 29.92inHg, 70°F
Motor: Hacker B20 18L; 3086rpm/V; 0.4A no-load; 0.092 Ohms.
Battery: Thunder Power TP2100; 2 cells; 2100mAh @ 3.7V; 0.022 Ohms/cell.
Speed Control: Castle Creations Phoenix 35; 0.0045 Ohms; High rate.
Drive System: Generic 9x6in Prop w/3:1 Gearbox; 10x6 (Pconst=1.25; Tconst=0.956) geared 2.8:1 (Eff=95%).
Airframe: GWS Formosa; 256sq.in; 18.5oz; 10.4oz/sq.ft; Cd=0.056; Cl=0.47; Clopt=0.66; Clmax=1.24.
Stats: 74 W/lb in; 55 W/lb out; 15mph stall; 21mph opt @ 63% (69:13, 75°F); 25mph level @ 73% (54:27, 76°F); 906ft/min @ 29.9°; -196ft/min @ -6.2°.
Power System Notes:
The full-throttle motor current at the best lift-to-drag ratio airspeed (11.2A) falls between the motor's maximum efficiency current (5.3A) and its current at theoretical maximum output (34.8A), thus making effective use of the motor.
Possible Aerodynamic Problems:
The static pitch speed (35mph) is less than 2.5 times the stall speed (15mph), 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 lower gear ratio, a higher cell count, or some combination of these methods.
Aerodynamic Notes:
With a wing loading of 10.4oz/sq.ft, a model of this size will have trainer-like flying characteristics. It would make an ideal trainer, for use in calm to light wind conditions.
The static thrust (17.3oz) to weight (18.5oz) ratio is 0.93:1, which will result in very short take-off runs, no difficulty taking off from grass surfaces (assuming sufficiently large wheels), and steep climb-outs.
At the best lift-to-drag ratio airspeed, the excess-thrust (9.2oz) to weight (18.5oz) ratio is 0.5:1, which will give steep climbs and excellent acceleration. This model should be able to do consecutive loops, and has sufficient in-flight thrust for almost any aerobatic maneuver.
General Notes:
This analysis is based on calculations that take motor heating effects into account.
In-flight Analysis - GWS - Formosa - Hacker B20 18L - 1060 Prop 2.8:1 GWS 350c "A" Gearing gearbox
25ft above Sea Level, 29.92inHg, 70°F
Motor: Hacker B20 18L; 3086rpm/V; 0.4A no-load; 0.092 Ohms.
Battery: Thunder Power TP2100; 2 cells; 2100mAh @ 3.7V; 0.022 Ohms/cell.
Speed Control: Castle Creations Phoenix 35; 0.0045 Ohms; High rate.
Drive System: Generic 9x6in Prop w/3:1 Gearbox; 10x6 (Pconst=1.25; Tconst=0.956) geared 2.8:1 (Eff=95%).
Airframe: GWS Formosa; 256sq.in; 18.5oz; 10.4oz/sq.ft; Cd=0.056; Cl=0.47; Clopt=0.66; Clmax=1.24.
Stats: 74 W/lb in; 55 W/lb out; 15mph stall; 21mph opt @ 63% (69:13, 75°F); 25mph level @ 73% (54:27, 76°F); 906ft/min @ 29.9°; -196ft/min @ -6.2°.
AirSpd Drag Lift Batt Motor Motor Input Loss MGbOut MotGb Shaft Motor Prop Thrust PSpd Prop Total Time
(mph) (oz) (oz) Amps Amps Volts (W) (W) (W) Ef(%) Ef(%) RPM RPM (oz) (mph) Ef(%) Ef(%) (m:s)
0.0 0.0 0.0 12.6 12.6 6.8 85.4 21.5 63.9 74.8 68.7 17051 6090 17.3 34.6 0.0 0.0 10:01
1.0 0.0 0.0 12.6 12.6 6.8 85.4 21.5 63.9 74.8 68.7 17051 6090 17.0 33.6 3.3 2.3 10:01
2.0 0.0 0.1 12.6 12.6 6.8 85.4 21.5 63.9 74.8 68.7 17050 6089 16.8 32.6 6.5 4.5 10:01
3.0 0.0 0.3 12.6 12.6 6.8 85.5 21.5 64.0 74.8 68.7 17045 6088 16.5 31.6 9.6 6.6 10:00
4.0 0.1 0.5 12.6 12.6 6.8 85.5 21.5 64.0 74.8 68.6 17039 6086 16.3 30.6 12.6 8.7 10:00
5.0 0.1 0.8 12.6 12.6 6.8 85.6 21.6 64.0 74.8 68.6 17033 6083 16.1 29.6 15.6 10.7 9:59
6.0 0.1 1.1 12.6 12.6 6.8 85.7 21.6 64.1 74.8 68.6 17026 6081 15.8 28.6 18.4 12.6 9:59
7.0 0.2 1.5 12.6 12.6 6.8 85.8 21.7 64.1 74.8 68.6 17020 6079 15.6 27.5 21.1 14.5 9:58
8.0 0.2 2.0 12.7 12.7 6.8 85.9 21.7 64.2 74.7 68.5 17014 6077 15.4 26.5 23.7 16.3 9:58
9.0 0.3 2.5 12.7 12.7 6.8 85.9 21.7 64.2 74.7 68.5 17011 6075 15.1 25.5 26.3 18.0 9:57
10.0 0.4 3.1 12.7 12.7 6.8 85.9 21.7 64.2 74.7 68.5 17009 6074 14.9 24.5 28.7 19.7 9:57
11.0 0.5 3.7 12.7 12.7 6.8 85.9 21.7 64.2 74.7 68.5 17011 6076 14.6 23.5 31.0 21.3 9:57
12.0 0.5 4.4 12.6 12.6 6.8 85.7 21.6 64.1 74.8 68.6 17027 6081 14.3 22.6 33.3 22.8 9:59
13.0 0.6 5.2 12.6 12.6 6.8 85.4 21.5 63.9 74.8 68.7 17051 6090 14.0 21.6 35.4 24.3 10:01
14.0 0.7 6.0 12.5 12.5 6.8 84.9 21.2 63.6 75.0 68.8 17094 6105 13.7 20.7 37.3 25.7 10:05
15.0 0.8 6.9 12.4 12.4 6.8 84.2 20.9 63.3 75.1 69.0 17150 6125 13.3 19.8 39.2 27.1 10:11
16.0 1.0 7.9 12.2 12.2 6.8 83.3 20.6 62.8 75.3 69.3 17218 6149 12.9 18.9 40.9 28.3 10:17
17.0 1.1 8.9 12.1 12.1 6.8 82.3 20.1 62.2 75.6 69.6 17299 6178 12.6 18.1 42.5 29.6 10:26
18.0 1.2 10.0 11.9 11.9 6.8 81.2 19.6 61.6 75.8 69.9 17391 6211 12.1 17.3 44.0 30.8 10:35
19.0 1.3 11.1 11.7 11.7 6.8 79.9 19.1 60.8 76.1 70.3 17495 6248 11.7 16.5 45.4 31.9 10:47
20.0 1.5 12.3 11.5 11.5 6.8 78.4 18.5 59.9 76.4 70.7 17610 6289 11.3 15.7 46.7 33.0 11:00
21.0 1.6 13.5 11.2 11.2 6.9 76.7 17.8 58.9 76.8 71.2 17745 6338 10.8 15.0 47.9 34.1 11:16
22.0 1.8 14.9 10.9 10.9 6.9 74.7 17.0 57.7 77.2 71.7 17898 6392 10.3 14.3 48.9 35.1 11:36
23.0 2.0 16.2 10.5 10.5 6.9 72.5 16.2 56.3 77.7 72.3 18069 6453 9.8 13.7 49.9 36.1 11:59
24.0 2.1 17.7 10.1 10.1 6.9 70.0 15.3 54.7 78.1 72.9 18255 6520 9.3 13.0 50.8 37.0 12:26
25.0 2.3 19.2 9.7 9.7 6.9 67.3 14.4 52.9 78.6 73.6 18455 6591 8.8 12.5 51.5 37.9 12:58
26.0 2.5 20.8 9.3 9.3 7.0 64.4 13.4 50.9 79.1 74.3 18669 6668 8.3 11.9 52.2 38.8 13:36
27.0 2.7 22.4 8.8 8.8 7.0 61.2 12.5 48.8 79.6 75.0 18897 6749 7.7 11.3 52.9 39.7 14:21
28.0 2.9 24.1 8.3 8.3 7.0 57.9 11.5 46.4 80.1 75.8 19136 6834 7.1 10.8 53.4 40.5 15:14
29.0 3.1 25.8 7.7 7.7 7.0 54.3 10.6 43.7 80.6 76.5 19387 6924 6.6 10.3 53.9 41.2 16:18
30.0 3.3 27.6 7.2 7.2 7.1 50.5 9.6 40.9 81.0 77.2 19648 7017 6.0 9.9 54.4 42.0 17:36
31.0 3.6 29.5 6.6 6.6 7.1 46.5 8.7 37.8 81.3 77.8 19919 7114 5.4 9.4 54.8 42.6 19:11
32.0 3.8 31.5 6.0 6.0 7.1 42.3 7.8 34.5 81.6 78.4 20199 7214 4.8 9.0 55.2 43.2 21:10
33.0 4.1 33.5 5.3 5.3 7.1 37.9 7.0 31.0 81.7 78.8 20489 7318 4.2 8.6 55.5 43.7 23:44
Note: Motor performance calculations take ambient temperature and heating effects into account.
Generated by MotoCalc 7.08, 3/4/2004 8:33 PM.