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Old Jun 26, 2005, 06:39 PM
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Stuttgart, Germany
Joined Oct 2004
966 Posts
Went flying, disaster averted........

Hey fellas,

I took my bird dog and 5 fresh packs out to the park, did a quick pre-flight and launched. I took it up to safe altitude and immediately noticed that something wasn't right. Either the wind was playing tricks or something was very wrong! It turned left sluggishly, but wouldnt turn right at all! The pre flight showed the rudder moving okay, but under flight loads it would not deflect to the right. I was trying to bring it around I lost it, augering in from 30' tearing the nose out and trashing the landing gear. Looking over the wreckage I found that some foamed gorilla glue had crept into the rudder hinge, and only by flexing of foam was there any deflection. I was fuming because we had just got there and now I had nothing to fly. My wife was very consoling, and suggested I run home and grab the Pitts Special. Angrily I walked home and retrieved it, and by the time I reached the park again, I was over the bird dog, and excited to fly. I pre-flighted her (thoroughly this time) and went out to the middle of the field to launch. One more radio check and my elevator stopped responding!! I was really disappointed that I wasnt going to get to fly today, and upon inspection i discovered a servo wire had become disconnected from the receiver board, it failed right above the solder joint. I was packing it up and really steeming about the whole mess. I kept thinking, 'why wasn't it the rudder servo that failed? I could do without the rudder, its only mixed 15% to the ailerons anyway.' HEY! WAIT A MINUTE! what if I plugged the elevator servo into the rudder port, and slaved rudder to elevator? Then when I applied up elevator, the rudder would deflect (which was now actuating the elevator) And so without any tools, I was able to switch the plugs, program the strange mix into my trusty Futaba 7CAP, and BAM! I had correct elevator! Even the elevator dual rates were functional! I knew with a lot of side area I would be fighting the wind vaning effect without rudder, but I had solid bank-and-yank control! I launched and immediately got a feel for this type of flying (this is my first aileron model, and only my second time flying it) The first few laps were hairy, I had the ailerons at high rates, but it still felt like there was little response until I applied full stick, then it was twitchy. I landed it and adjusted the exponential from -50 to -15, and relaunched. Immediately it felt better. I could now make nice shallow turns without losing any altitude, and could bank it over and pull back for a very sharp turn. I didnt want to be too daring with my hokey makeshift mixing, but couldnt resist a loop! It stalled at the top in the wind and only pulled out at the bottom about 2' above the grass WHEW! almost dumped it! After the throttle started to sag, I landed for a new pack and noticed that the pack was puffed up a little and quite hot. I propped down to an 8x4.3 and launched again. This time everything was smooth, and I was able to use a little less throttle. I think at full throttle, the 9x4 prop was pulling more amps than the pack could sustain, and the voltage was sagging, reducing thrust output, and the overload caused the pack to swell. After running another pack the battery was quite hot but not swollen, leading me to think that I need to re-wind my GBx double. it currently has 9 turns of double strand 26ga wire, and using my cheapo E-tec 1200mAh classic 2 cell lipos, it seems to be pulling too much current for these packs. any suggestions? maybe I need to make the jump to 3 cell packs, but that means a new charger, and my brushless speed controller is only rated for 10amp service. The plane weighs 11oz with the current setup. Overall, the plane flew great, needing no trimming to transition from pretty, slow flybys to high speed passes and pylon style turns. What a great design, very impressive looking in the air and a real pussycat to fly at low throttle, but handles like a racer at full throttle. And wouldn't it figure I forgot the camera and couldn't get a decent shot with my cell phone. I think I'll head back to the field tomorrow.

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Last edited by JayJay76; Jun 26, 2005 at 06:55 PM. Reason: spelling
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