Still Isolate Your Ignition from 2.4 Ghz Radio Systems!
10-07-2007, 07:29 AM
#1
Still Isolate Your Ignition from 2.4 Ghz Radio Systems!
I've been flying a Top Flite P-51 ARF Mustang on the new 2.4 Ghz Spectrum DX7 and having trouble. For the past two weeks the landing gear have been cycling randomly without command from the transmitter. The airplane would not go into fail-safe and I maintained complete control. It would cycle randomly a dozen or more times during any given flight. To trouble shoot this I changed the servo on the air valve, changed the air valve, I even switched the servo from the gear channel to the AUX 2 channel and it still cycled randomly. I concluded that it must be a bad 2.4 Ghz AR7000 reciever.
Yesterday I completely switched radios to the a new 2.4 Ghz JR 9303 and a new AR9000 receiver. To my amazement the gear still cycled randomly during the flight. Since I had control I decided to observe the malfunction while in the sky. What I learned is that it would not happen anywhere below 1/2 throttle and it happened mostly while in a left hand turn. My electronics friend Pierre Deschenes said, "Land the plane, I know what it is."
I pulled the wing off the plane and Pierre pointed out that I had installed my ignition battery about 1 inch away from the servo that operates the retracts. I thought I could do this because 2.4 Ghz is not supposed to be effected by engine noise. This turns out to be true for the receiver but not for any individual servos. The servo are still effected by ignition noise translating back through the battery at higher throttle settings. This was amplified during a left hand turn as the servo wire came even closer to the battery. So I moved the battery and the problem is solved.
Moral of the story is that it wasn't the 2.4 Ghz system and that you still need to isolate your ignition system from the radio on 2.4 Ghz systems because of the servos.
Leo
Yesterday I completely switched radios to the a new 2.4 Ghz JR 9303 and a new AR9000 receiver. To my amazement the gear still cycled randomly during the flight. Since I had control I decided to observe the malfunction while in the sky. What I learned is that it would not happen anywhere below 1/2 throttle and it happened mostly while in a left hand turn. My electronics friend Pierre Deschenes said, "Land the plane, I know what it is."
I pulled the wing off the plane and Pierre pointed out that I had installed my ignition battery about 1 inch away from the servo that operates the retracts. I thought I could do this because 2.4 Ghz is not supposed to be effected by engine noise. This turns out to be true for the receiver but not for any individual servos. The servo are still effected by ignition noise translating back through the battery at higher throttle settings. This was amplified during a left hand turn as the servo wire came even closer to the battery. So I moved the battery and the problem is solved.
Moral of the story is that it wasn't the 2.4 Ghz system and that you still need to isolate your ignition system from the radio on 2.4 Ghz systems because of the servos.
Leo
