Wing Dragon Sportster 27MHz electronics
12-09-2005, 03:54 PM
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Wing Dragon Sportster 27MHz electronics
I purchased a Wing Dragon Sportster in September (2005), on eBay at a good price. I crashed it a few times and then broke it beyond repair. I did like the plane, and the price was right, so I got another one. My plane has a 27.095 MHz . I found a couple of design problems in the electronics that I've had to fix to fly safely.
When I assembled the 2nd plane, the ailerons had large random movements. This was because two servos connect to one RC receiver channel. The receiver cannot produce enough control voltage for 2 servos in parallel. I had to change 2 resistors in the receiver to solve the problem before I could fly. This might explain why one reviewer mentioned the plane is "unstable" in the roll axis.
Out at the field, during my radio check with the servos chattering, all servos (ailerons, elevator, rudder) locked up hard-over!!! I had to disconnect the battery to get them working again. Back home I found the problem. The ESC has a 5 volt ragulator to power the radio and servos. With a lot of servo movement, the regulator overheats and drops to 3.5V, then the radio fails and the servos lock up. I think this caused one crash of my first plane. The cure this, I had to remove the 5V regulator from the ESC and wire in a 5 volt 5 amp regulator with a heat sink, mounted elsewhere in the fuselage.
Now, the plane flies fine. Four flights on the new one, no crashes, doing loops and stalls. No inverted or outside loops yet, I need more practice and the motor power might be a bit low.
Static, I measured full thrust at about 0.9-1 lb with the battery current at 13A. At about 8-10A normal flight power, theoretical flight time is 6 minutes for the 1AH NiMH battery. I get 6-7 minutes on my flights.
Otherwise, the electronics is well made (I'm an electrical engineer). My ESC and radio were manufactured in Nov 2003 (ESC board EESCA150A002 and radio board RM-202 Ver 5.0). Perhaps these problems have been corrected in newer versions.
When I assembled the 2nd plane, the ailerons had large random movements. This was because two servos connect to one RC receiver channel. The receiver cannot produce enough control voltage for 2 servos in parallel. I had to change 2 resistors in the receiver to solve the problem before I could fly. This might explain why one reviewer mentioned the plane is "unstable" in the roll axis.
Out at the field, during my radio check with the servos chattering, all servos (ailerons, elevator, rudder) locked up hard-over!!! I had to disconnect the battery to get them working again. Back home I found the problem. The ESC has a 5 volt ragulator to power the radio and servos. With a lot of servo movement, the regulator overheats and drops to 3.5V, then the radio fails and the servos lock up. I think this caused one crash of my first plane. The cure this, I had to remove the 5V regulator from the ESC and wire in a 5 volt 5 amp regulator with a heat sink, mounted elsewhere in the fuselage.
Now, the plane flies fine. Four flights on the new one, no crashes, doing loops and stalls. No inverted or outside loops yet, I need more practice and the motor power might be a bit low.
Static, I measured full thrust at about 0.9-1 lb with the battery current at 13A. At about 8-10A normal flight power, theoretical flight time is 6 minutes for the 1AH NiMH battery. I get 6-7 minutes on my flights.
Otherwise, the electronics is well made (I'm an electrical engineer). My ESC and radio were manufactured in Nov 2003 (ESC board EESCA150A002 and radio board RM-202 Ver 5.0). Perhaps these problems have been corrected in newer versions.
