Metal covered DC-3 glitches.
06-02-2007, 06:36 PM
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Metal covered DC-3 glitches.
I have a Ziroli DC-3 that I have not yet flown because of a glitch problem that occures when the engines are running.I'm using a Futaba 9C radio/receiver and a SmartFly power expander,2 JR 6 volt batteries,JR switches.645 Hitec servos.
The receiver and power expander is hung from the top of the fuse between two formers near the c/g and hangs down about an inch from the top of the cabin.The antenna goes through a nyrod tube through the skin(balsa covered with glass, covered with flitemetal)back towards the fin.
The whole aircraft is covered with flitemetal .The engines at first were US41's and I was getting glitches with them.I now have Fugi 32's with EI and I'm still getting glitches.I tried different receivers,2 receivers,different receiver locations(moved it back 5".I had metal pull pull (plastic covered) rudder cables that I thought might be the problem so I changed them to non metal lines and still no luck yet.
I have run the engines with the centre wing section separated from the fuse with success,so I laid down a thin layer of rubber between the wing saddle and the fuse bolted it together and it still glitches.I'm doing all my recent tests in a single car garage.
I'm thinking the metal is carrying the ignition noise to the receiver somehow.Is it because the antenna is protruding through the metal covered fuse?What about using 2.4GHz?
Thanks for any thoughts..Steve
The receiver and power expander is hung from the top of the fuse between two formers near the c/g and hangs down about an inch from the top of the cabin.The antenna goes through a nyrod tube through the skin(balsa covered with glass, covered with flitemetal)back towards the fin.
The whole aircraft is covered with flitemetal .The engines at first were US41's and I was getting glitches with them.I now have Fugi 32's with EI and I'm still getting glitches.I tried different receivers,2 receivers,different receiver locations(moved it back 5".I had metal pull pull (plastic covered) rudder cables that I thought might be the problem so I changed them to non metal lines and still no luck yet.
I have run the engines with the centre wing section separated from the fuse with success,so I laid down a thin layer of rubber between the wing saddle and the fuse bolted it together and it still glitches.I'm doing all my recent tests in a single car garage.
I'm thinking the metal is carrying the ignition noise to the receiver somehow.Is it because the antenna is protruding through the metal covered fuse?What about using 2.4GHz?
Thanks for any thoughts..Steve
06-02-2007, 07:15 PM
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RE: Metal covered DC-3 glitches.
06-03-2007, 06:18 AM
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RE: Metal covered DC-3 glitches.
Yes thats a very interesting read Bruce,I just picked up a Fut 6 FASST and will do a test myself.I really need 7 ch for my 3 but the 6 ch will do for some testing.I have the 8ch module on back order ..
Steve
Steve
06-03-2007, 07:53 AM
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RE: Metal covered DC-3 glitches.
Hello Steve:
You should have contacted me about your problem when it started. I may have been able to save you time in resolving this. I have had one other customer experience this. He was also using a US41 in his TF P-51 with an Airtronics, then a Futaba receiver. Both receivers experienced EMI from the motor. He eventually replaced them with a new Futaba receiver and the EMI stopped immediately. The two receivers he experienced the issue with had previously been in crashed planes.
I'd look into acquiring either a new Hitec or Futaba receiver.
You should have contacted me about your problem when it started. I may have been able to save you time in resolving this. I have had one other customer experience this. He was also using a US41 in his TF P-51 with an Airtronics, then a Futaba receiver. Both receivers experienced EMI from the motor. He eventually replaced them with a new Futaba receiver and the EMI stopped immediately. The two receivers he experienced the issue with had previously been in crashed planes.
I'd look into acquiring either a new Hitec or Futaba receiver.
06-03-2007, 11:21 AM
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RE: Metal covered DC-3 glitches.
I tried a new Hitech receiver and was still getting them Ed,I just tried the new Futaba 2.4 receiver and its looking promising,we'll see soon.I still have to finish the installation,I'll keep you posted..
Steve
Steve
06-04-2007, 08:07 AM
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RE: Metal covered DC-3 glitches.
Yep RCJ6Y's Ed,rubber hoods.These Fugi's are nice.Also my glitching has stopped,I installed a Futaba FASST 6 ch in her as per the manufacturers instructions and haven't had a single glitch yet while running the engines in my shop.It seems like 2.4 GHz is the answer in this case.I dunno Ed I'm sure theres an answer to the glitches I was getting on 72mg,but I really like how this new radio is working.Albeit only 6 ch on a big twin,I have to put up with single stage flaps,and throttles on only one channel,but I can deal with that.Once the Futaba 8 channel modules come out I'll install it.I still have finish up a few things before I bring it out for some taxi tests later this week ...
Steve
Steve
06-04-2007, 08:31 AM
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RE: Metal covered DC-3 glitches.
I invite you to review the antenna placement used by George in the TU4. He used a plastic sleeve to assure the antennas remained in the preferred 90 degree angle to each other and 45 degrees to the fuselage when mounted in the "top" of the fuselage protruding to the outside.
George rationalized the top is better than the bottom as the antenna will most likely be exposed to the direct signal from the transmitter antenna during the majority of all scale maneuvers. I will place a close up image of George's antenna set-up below.
George rationalized the top is better than the bottom as the antenna will most likely be exposed to the direct signal from the transmitter antenna during the majority of all scale maneuvers. I will place a close up image of George's antenna set-up below.
06-04-2007, 10:01 AM
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RE: Metal covered DC-3 glitches.
I placed mine the same way except on the bottom of the fuse at the trailing edge Ed.I was thinking the radio antennas would be more exposed that way.I'm not sure if it really matters,has George or anyone done any testing both ways?
Steve
Steve
06-04-2007, 12:05 PM
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RE: Metal covered DC-3 glitches.
Believe I would not expose that much of the soft wrapped antenna beyond the tube...it will fold back when at speed. That was George's rationalization on the tube length. As for top or bottom, If on top the antennas are less likely to be out of a direct line of sight with the transmitter. Imagine a hard right or left turn...
