Setup
Motor
Turnigy 4260-500
ESC:
Plush 80A
Servos:
Futaba S3001 (elevator/rudder) +
Turnigy 1160A (ailerons)
Prop: APC 15x8E
Battery1:
Rhino 4S1P 3700mAh 25C
Battery2: ECPower (effectively, noname) 4S1P 5000mAh 15C
Receiver: Futaba R149DP
Weights
Wing (Glued, 2 aileron servos, extensions, etc):
377.6g
Fuselage (landing lear, elevator and rudder servos, extensions, motor, esc, receiver, prop, spinner, etc):
1,009.8g
Battery1:
396.6g
Battery2:
439.79
AUW (with battery 1, see below):
1,785g
Pre-flight
The 5000mAh battery is too weak to provide the required current. On the Watt-Meter, at WoT, one sees 380W at low current. The battery was used for trim tests, channel reverse, etc.
The 3700mAh battery gave better results - 450W at 30A (I seem to be over-ESC'ing :-). This is still lower than my expectation. Might be too large a prop, I will reduce and re-test.
Power/Weight Ratio:
107W/lb input power
ROG and flight
Test flight in slightly windy conditions, light gusts across the landing strip.
Take off from paved road, slow roll with gentle throttle ramping, run of some 8-10m then (at around half-throttle) a very sudden and surprising pull up at more than 45 degree angle - most likely my fault as this was my virgin test flight. I added a bit more power, let it rise to TMH (two/three mistakes height) and turned it into the gusts. One up and one right click trim needed.
I did not want to run it long, not knowing how quickly it will eat the juice, so after five leisurely circuits (all around 1/3-1/2 throttle), turned into landing.
Problems started here - the antenna extension has somehow gotten twisted into the rudder wheel, reducing rudder movement (which is NOT very great to begin with on the Mentor). This threw me and I stalled the plane about 50cm higher than I should have. A gentle cartwheel into the brambles was all the damage that occurred.
Post Flight
The plane is very gentle and responsive. I did NOT feel that the plane lacked power, for at 100W/lb, it is over-powered for a trainer.
I think that the rudder needs more throw. I also dislike the rudder push-rod - it is much too flexible and I need to think how to stiffen it.
Will tape the final 3" of the antenna to the fuselage, lest I have a repeat of the antenna-in-wheel syndrome.
Will also tape the edges of the control surfaces - they seem much too flexible and bendy.
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