Servos are 9gm for ailerons with two push-pulls, and 5gm for rudder and elevator, mounted in a single file on the top of the model, superglue in placed. In future, I shall not use the 5gm servos that I bought from Jethobby. These 5gms were intended for Mini-Popwing but which I didn't use them because they stalled too easily. I installed them on this bug e-fun but they stalled occassionally. These 5gms servos are too weak.
The Turnigy 1806motor and 6A ESC (both from HobbyKing) and a GWS 5x3 propellor provides ample thrust. The motor is mounted with its radial mount (I deem the motor shaft too short for direct grip with nylon ties) on a 2mm ply-faced 1/4" balsa firewall with 2mm socket bolts and blindnuts (the radial mount and firewall probably weighs as much as the motor itself). The firewall is first glued to a 2mm carbon fibre rod pylon. As the throttle increases, the whole motor rotates downwards, giving more downthrust. Interesting to have variable downthrust but not a good idea for reliability. The rod was then replaced with a 5x1mm carbon fibre strip. No more variable downthrust but it snapped when crashed. Finally, the firewall was just epoxied onto the nose.
With Hitec receiver in the canopy region, and a 450mah battery (bought from Rotor Hobby, tagged as 500mah) push fitted in a slot below the wing, the model flies good. There must not be too strong of a gusty wind.
It flew ok. Rolls, loops, inverted are ok but not straight and true. Stall turns are iffy with the smallish rudder and I got about 10 minutes of flight time. Maybe it is the Turnigy 6A ESC, it is warm even at zero throttle and I didn't have this symptom with the Turnigy 10A ESC. Anyway, 10minutes is good enough, I like the smallness of the 6A ESC and will use them, but next time, I shan't use the 5gm servos, I shall use the 9gm servos like Hitec's HS 55.
This experiment was done to evaluate how the 1806 10gm motor feels. I find this airborne package ok, although the 6A ESC was warm and the 5gm servos quite useless.
Now that I have an idea of what it can deliver, I can do up more interesting models using them.
How about a scalish Gee Bee Model D Sportster or since I have two of this motor and esc, a scalish twin of some sort? Short-nosed subjects like the Sopwiths are still out of bounds until I can figure out how to concentrate the weight to the nose which currently. Maybe I will find reliable 5gm or sub-5gm servos one day.
Update 16/12/2013
My two Mini-Popwings are down. One with a motor wire pulled out of the connector and the other a jittery servo. I am left with the mini piper cub and the Bug e-fun. For 'challenge', I flew the Bug e-fun yesterday.
I flew 6 batteries, during these flights I added 10gm of lead to the tail. The model was nose-heavy to start with.
The flight times of flying freely with full use of throttle and conservatively with gliding time was not of appreciable difference. The batteries lasted about 9 minutes for both forms of flying. I thought it would either be the ESC or that I have over-propped the motor with a GWS 5x3. I swapped in a 12A Hobbywing's for one flight. It seemed slightly more spirited, but the flight time was similar. Perhaps the 2900kV was overworked and hence drawing more amp while the propeller flips over at less than 90% of the 2900kV. I tried a GWS 4.5x4. This is better.
I could do rolling circles with this model. The rudder is however too small and the rolling circles relied on elevator input instead. Perhaps if the rudder is bigger the model might have a chance of doing knife-edge. (I doubt it, but still, it is plausible)
No comments:
Post a Comment