MotOpinion - Sig LT-25 Twin
1000ft above Sea Level, 68°F
|| Kyosho Atomic Force 17T; 3531rpm/V; 0.035 Ohms; 2.94A idle.|
|| Sanyo RC2000; 14 cells; 2000mAh @ 1.2V; 0.0035 Ohms/cell.|
|| Stefan's 4-FET ESC with BEC and Brake; 0.0025 Ohms; High rate.|
|| Master Airscrew 3.0:1 Gearbox w/APC Prop; 2 motors (series); 10x7 (Pconst=1.11; Tconst=0.95) geared 3:1.|
|| Sig LT-25; 724sq.in; 104.7oz; 20.8oz/sq.ft; Cd=0.063; Cl=0.52; Clopt=0.69; Clmax=1.2.|
|| 30A max, 48A max (ESC), 51 to 64mph, 240sec min.|
|| 58 W/lb in; 44 W/lb out; 22mph stall; 29mph opt @ 67% (16:40); 33mph level @ 74% (13:58); 623ft/min @ 14.2°; -288ft/min @ -6.5°.|
Power System Notes:
- The full-throttle motor current at the best lift-to-drag ratio airspeed (23.5A) falls between the motor's maximum efficiency current (23.3A) and its current at maximum output (93.8A), thus making effective use of the motor.
- The voltage (15.6V) exceeds 12V. Be sure the speed control is rated for at least the number of cells specified above.
- The static pitch speed (53mph) is within the range of approximately 2.5 to 3 times the model's stall speed (22mph), which is considered ideal for good performance.
- With a wing loading of 20.8oz/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 (52.7oz) to weight (104.7oz) ratio is 0.5:1, 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 (27.4oz) to weight (104.7oz) ratio is 0.26:1, which will give strong climbs and rapid acceleration. This model will most likely readily loop from level flight, and have sufficient in-flight thrust for many aerobatic maneuvers.
- This analysis is based on calculations that take motor heating effects into account.
Generated by MotoCalc 6.05, 2002-04-01 21:01.