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Zurich
Joined Apr 2006
3,167 Posts
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Quote:
In my extensive experience w/5888s, I have never seen pinion stripped, but often, many times, a loose pinion! This is due to low-cost "QC" for the radii of both the cheap motors' shafts and the pinion-bores. Simply remove the pinion, use a micro amount of CA gel [NEVER use liquid CA on these helis!; epoxy is a good second choice] on the shaft, then quickly insert and position the pinion. [NOTE: the optimal position is usually with one edge of the pinion flush w/ main gear edge, not in the center of the pinion! > test by holding heli inverted to force rotor-shaft "up" into flying position, and hand turn rotor slowly in reverse!!] Lee
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Zurich
Joined Apr 2006
3,167 Posts
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tuning tip
While adjusting blades today I was reminded of the following:
1. The (mechanical/electrical/aeroelastic)* optimal blade "tip-play"/looseness of the alu blade-holder/hub-hinges of > 4mm upper rotor 3mm lower rotor which allows the fwd-swept blades to twist their pitches under flt-load such that [w/NEUTRAL yaw!] the lower rotor disc appears ca. 10% thicker [more pitch, as needed in accelerated lower airflow!] when viewed edge-on .... is based on the assumption that the upper & lower blades have the same thickness (and thus equal torsional resistance!). 2. One can check thickness/torsion-resistance by flexing each blade downward at its tip-rear. 3. In case the lower blades are (torsionally) stiffer than the upper, the tip-play and/or the actual pitch of the alu plates must be adjusted to compensate, to allow the lower rotor to assume ca. 10% greater pitch than the upper, under power in hand, yaw-neutral trim! [Luckily I could merely install equally stiff upper & lower blades]. 4. NOT doing the above, even with perfect tracking, will reduce flt. times, effective power & performance .... and motor life ... by as much as 30 - 40% !! Lee ![]() *I have repeatedly checked this "concept" with a strobe > both rotors revealed to be spinning with the same speed/RPM when lower rotor disc ca. 10% "thicker" [more pitch]. |
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Zurich
Joined Apr 2006
3,167 Posts
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Quote:
Pinions come with new motors .... note: loose pinions can be adhered with CA gel L
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Joined Jan 2012
2 Posts
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Alu hub screw holes
Hi Lee, or anyone caring to answer.
I have been really enjoying my 5888 and have also used your tips for tracking and tuning. But what's happened to me twice now is that I overtighten the screws on the blade hubs, and then they become loose. I now know, that the tightening needs to be done by 'micro-bending' the alu hubs, and not tightening the screws. However, that is now too late, and I have another loose screw (already replaced the alu hubs once, pain in the ass). Do you have any tips to fix this? Apart from ordering another set. I was thinking of adding a tiny bolt to the screw, but I'm not sure those are made in that size. Hope to hear from you. |
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saratis, I'm sure Lee would have a better solution for this, but I've put a tiny drop of super glue on top of the loose screw on mine, it is still holding up after several weeks. Of course you do this only when you have the blades tuned to your satisfaction and don't plan to tinker with it often.
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Zurich
Joined Apr 2006
3,167 Posts
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got a screw loose?
ahem .....
![]() [anyway, they are actually bolts, not screws, in this case] I do three things, in this order > 1. Remove the blade, being SURE* not to lose the essential tiny brass bushing! Then I put a micro-drop of CA gel [NEVER use liquid CA!!!!] in the hole with a round toothpick and heat-cure it quickly with a hairdrier, avoiding heating the rest of the heli so much as possible. 2. Reinsert the blade and screw in the bolt to give the desired "tip-play" looseness. [b.t.w., within limits, the looseness IS adjustable with BOTH of the bolts, the inner one for fine-adjustment: just be careful not to strip the alu plate's threads]. Run up the heli in your hand and check for tracking, readjusting the bolt .... 3. THEN invert the heli and put a glob of CA gel around the exposed lower end of the bolt. Allow an hour to solidly cure. Once I've tracked & adjusted the blades, I put a glob of CA gel on ALL the exposed bolt-ends: this not only holds the adjustment, but keeps the bolts from stripping the alu plate threads! L ![]() *[note: I remove each bushing and use a toothpick to put a micro-drop of CA GEL in the blade hole, remove most of the CA with the toothpick, cure it, then re-insert the bushing with another round toothpick until it is loose enough to come out ONLY with force> it needs to be able to move very slightly in the alu hinge to self-adjust its position] |
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Zurich
Joined Apr 2006
3,167 Posts
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Quote:
After the bolt is functioning and rotatable, ADJUST blade for perfect tracking, then SEAL with more CA gel > add a blob around exposed bolt end and allow several hours to get rock-hard. Lee
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Zurich
Joined Apr 2006
3,167 Posts
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notes from a 5888 mechanic/repair-person
I got a used 5888 from Marcel that supposedly only needed a new LIPO, which I bought plus 2 new motors, all for Sfr/USD$22, total. Marcel imports lots of R/C helis & planes so he can keep some for himself because he is an avid R/C hobbyist. When he told me that this used heli, which he said was one I "set up" for him, flew great and to only change the LIPO, I believed him.
But, as a practical person, I checked it out at home and found: 1. There was a LONG thin wire strand caught in the swashplate ["bearing" in 5888 parts list]. 2. The left motor was a replacement white-topped one [that is GOOD, and the only reason I bought the heli!], that he had installed by running the wires outside the heli and twist-connecting the wires from the PCB. He had obviously done this before, and the wire strand must have come from an earlier such attempt, in which the swashplate ate the loose wire and took the strand from it. 3. The right motor did not turn at all! I tried another motor, rechecking all connections. Maybe the screwed-up swashplate caused something to overheat and kill a part in the PCB. Or maybe not. [NOTE: when I first take off the cabin from a new heli I use blobs of CA gel on all the motor and LED wires where they are soldered to the PCB. It is exremely difficult to re-solder those PCB connections without ruining something heat-sensitive!! So the CA gel secures those joints! THEN, when replacing a motor, I leave one end of the motor wire attached to the PCB and cut that wire long enough to allow a safe solder-joint away from the body, thread the new motor wires as first installed through the body at the factory, solder the wires and put some CA gel around the joint for insulation AND mechanical strength, then stuff back inside the cabin space. The slight extra length of wire barely diminishes performance and is a SAFE repair.] 4. The left motor did rotate the lower rotor, showing it to be BADLY untracked! My point is that even an experienced heli pilot was unaware of this, or at least did not notice it. Trust me: perfect razor-sharp tracking adds more performance that you might believe [all of mine now fly TWO TIMES faster and better than what was shown in my "birthday party" YouTube video, since I learned how to really track & tune these 5888s!!] 5. So the HELI was "trash" but i used the motors, LIPO and fast servos in an otherwise "dead" old one of mine. In so doing, I discovered > 6. The main gears can vary in diameter by so much as 1mm! And the motor pinions also vary. I had to try 3 different main lower gears and 8 different pinions untill I found a combination that was able to rotate smoothly with almost no resistance [heli inverted, rotor hand-rotated in reverse], not tight, but not, as TOO many are, so loose that the gears slip and click periodically, causing no-end of resistance, and mistaken by most users as a stripped gear [they are NOT stripped, just too far apart/loose!] 7. After 5 days and 10 hrs total work trying different blades [proper differential of upper vs lower rotor blade softness so that the heli would not turn left when adding power], tracking and lowering coning angles to reduce the sensitivity of the HOT servos' input, but still stable enough for comfort] .... I have a GREAT "new" heli! Lee
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Joined Jan 2012
1 Posts
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Hi all,
I just bought a 5888 heli but it wont connect/bind with the remote, it just stands there blinking it's lights at me. :P I tried the re-bind by having the heli on and then pressing the right stick on the remote while turning it on. The remote flashes and beeps for a few seconds before showing a steady red light, just as it should. But still no connection with the heli. Anything else I can try or is is just to consider it broken and return it for a new one? Thanks jAW |
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United States, MA, Natick
Joined Jun 2011
475 Posts
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I have a 5888 and 5889. I am trying to fly both off of my turnigy 9x (flashed with er9x). I have been able to bind them but the 5888 is not very stable, and the 5889 just spins its tail rotor full blast anytime i touch the throttle. any tips?
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