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Old Aug 05, 2010, 09:45 AM
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Another major factor is "Free Mkt Capitalism"; i.e., look at how prices drop with competition and follow market fluctuations ....

killbucket: pls let me know if you need connections to some quality, low cost factories in China (one of "my" factories was where Hirobo [then world-leader in hobby helis] developed their coax "Lama", which design-concept has since been MUCH copied (Hirobo forced the factory to flt-test each one, since the USA purchase price for these was ~ USD $500 in 2010 dollars!).


Lee
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Old Aug 09, 2010, 08:13 AM
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Review

I really like it!

This largely METAL heli is larger than my truly beloved metal G.T.QS9008's, with 190 mm vs 170 mm rotor span. I calculated the volume* disc loading to be ~1/3 less than the 9008, and it shows. The electronics, IC-programming, "gyro"*** with trim memory and Tx are super, and the mechanics are generally fine, but it took a LOT of work & time to perfectly track the blades, give greater pitch to the lower rotor (aerodynamically important!) (as well as reduce the coning angles a bit). This was possible (hairdrier heat + twisting/bending) even with the loose blades. The blades keep needing readjusting, so as with my now-PERFECT 9008, I plan on slightly thickening the attachment sections at the blade roots with CA gel: the thus-"modded" 9008 now keeps its perfect tracking & stability-enhancing reduced coning angles**** after lots of steady use! > http://www.rcgroups.com/forums/showt...w#post15722707

One problem was that the lower rotor shaft-attachment piece was skewed and not perpendicular to the shaft, but once I figured that out, was easily fixed by hairdrier heat (there's plastic between the metal plates), twisting, re-heating and revving the rotors for a "perfect" alignment.

The next major problem was that the swashplate was not level under flight load, TOO much so for the cool electronic trims to correct. I had to hairdrier-heat the plastic arms attached to the swashplate to get it perfectly aligned.

All of the above was absolutely necessary because:

1. proper hover-neutral trim is very important for every "real" heli (especially to avoid crashing!), and

2. having read above about one 5888 soon becoming "wobbly", I knew that long-life critically depends on reducing & eliminating as much vibration as possible!

Even tiny vibrations, almost too small to feel in this micro-size, will cause eventual deterioration of the mechanics. Years ago a very high-up (in the corporate ladder) Lockheed helicopter engineer told me that these engineers' main job was hunting down and eliminating ALL vibrations (many of which were "telegraphed"!) ....!

Once properly tracked, etc., the sound changed to that of a fine sewing machine .... and it's a true pleasure to fly!!

I must mention, though, that this cheap toy did work OK from the beginning, but I naturally enjoyed "raising its standards" to a higher level. The Tx is cool, and the sticks feel very nice. It's great to be able to let go of the left stick (I use thumb + forefinger for max precision) and fiddle with the trims (8 buttons!) as the "gyro"-stabilized heli steadily maintains its last hover (or near-hover) position in 3-space, incl. altitude!

I still have to re-practice my 4-ch heli skills*****, and this toy/hobby item is perfect. It's at once easy, stable AND quickly maneuverable (lower disc loading than the 9008), and the "low-rate" position isn't even needed.

As a testament, even out-of-trim > NO CRASHES!

On the box it's written that this heli is "emulational" (creative Chinese-English), here meaning it copies the large R/C helis with scale looks and performance. It does....!

The seller > Marcel Hauser <marcelhauser@bluewin.ch>


happiLee


*aerodynamic forces involve changing the momentum [mv] of airflows**, and the mass [m] of the air moved varies with its volume!

**F=ma = m(dv/dt)

***"gyro" is a misnomer for these static non-rotating piezo-electric accelerometers!

****as with my 9008, the top visual edge of the spinning lower rotor disc is made/hairdrier-heat bent to be flat across, the upper slightly positive (~+1.5° more than the lower disc), the mean chord line of both thus slightly positive (actual coning angle)

*****a good trick to help both brain-halves stay in the same frame of reference is to think of the left yaw-stick as always moving in the same yaw-rotation direction as that part of the heli radially farthest from you (i.e., if the heli is facting left w.r.t. you, the stick will move the right side of the body in the same direction that the stick moves)
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Old Aug 10, 2010, 09:29 AM
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WoW!!

Hooray for Science & Engineering! [Observation + Praxis]

After temporarily removing the tiny brass blade bearings, adding a thin layer of CA gel to the blades' root-attachment sections (only slightly loose up/down and free to swing), re-pitching, re-tracking (lots of fun!) and trying different upper & lower rotor coning angles, the solution set for the 9008 ( http://www.rcgroups.com/forums/showt...e#post15722707 ) proved best for this 5888 as well!

This thing really sings now ....!

1. it's even more stable than before, and

2. still quickly maneuverable

3. the blade settings stay & are consistent

4. it's like flying a virtual heli in a video game ....!


Basically, it now flies exactly where I want, w/o needing constant correction (the stability acts like a spring, giving a kind of damping feedback), as if it now has a 3-axis "gyro"! Neutralizing the sticks slows the heli's motion: whereas before, with neutral "stability", it wanted to keep going (it still does, a bit, because of its momentum, having TWICE the disc-loading of the mCX).


Cool! Love it!
Lee
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Old Aug 12, 2010, 10:54 AM
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NOT wobbly!!

Quote:
Originally Posted by S107 View Post
mine died ... things got wobbly on it quick anyways. only good thing is its not far off for them to work good.
After doing what I planned, re: PERFECT tuning/adjusting (pls see my above posts) and NOT crashing ..... after many, many flights and more tip-overs than I'd like ... this cute Chinese GEM just keeps getting better & better!

That is, it is extremely precise and runs smoother & smoother .... quite the opposite from wobbly!

Me be very happy!
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Old Aug 13, 2010, 11:19 AM
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oh .... yeah! :)

Now that I've got the 5888 REALLY dialed-in .... it rocks!

I can horse it around just like the 9008: the blades & heli shudder for about a quarter-second, then QUICKLY stabilize! It almost acts like a hot 3-D heli with a very skilled pilot at the sticks (I am no so skilled, but the "rigidized" blades and flattened coning angles obviously add LOTS stability and responsiveness.

FUN!

I asked Marcel (his email is above) to bring me another one to the flea mkt. tomorrow for a spare (I love it SO!) ....


Lee
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Old Aug 17, 2010, 06:57 AM
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re: "wobbly" !

I've now bought 3 of these (I really love them and like to have spares in case they get discontinued, esp. since I'm getting them from an "irregular" but cool/good importer!). After a while the "worst" one, which I chose for regular use and then tuned, tracked and adjusted [see * below] for perfect flight, started a ~1 Hz oscillation (body rocking in 3-D > yaw, roll & pitch!).

After much! experimenting I finally realized that because the blades are actually swept forward in flight (these are hinged close to the front of the blade, so the mass of the blade pulls it fwd while rotating, like letting the blade statically hang down loosely with the shaft horizontal while not in motion, with gravity replacing the centripetal accelerative force ["good" helis, large or small, are ~neutrally hinged more rearward to allow individual blade pitch.change]).

That means that as the blades gradually loosen with use *(the "soft" metal blade holders are bendable: I use fingers or a toothpick to adjust looseness, pitch and coning angle!), the blades start to increase pitch starting at the tips .... and they slow down! Then the 45° stabilizer-bar top rotor input and the 90° lower rotor swashplate control input start obvious interaction resulting in total-system oscillation!

At the designed high rotor speed this interaction is too fast for the system to respond, and disappears into the background system "noise".

So, if it starts to rock, slightly flatten the pitches a bit (and re-track!)


Lee
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Old Aug 17, 2010, 08:18 PM
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if you notice all the rear body metal is for looks only and covering a completely structurally intact chassis. you can remove it off to make it less of a pig.. and the motors on mine died
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Old Aug 18, 2010, 10:39 AM
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Quote:
Originally Posted by S107 View Post
if you notice all the rear body metal is for looks only and covering a completely structurally intact chassis. you can remove it off to make it less of a pig.. and the motors on mine died
after my extensive, careful tracking & "tuning", it "gained" about 30% - 40% power* and is NOT a "pig". and I LIKE the metal and how it flies.
MINE is a HOG (as in H-D!).

I should note that the motors DO get hot, so I let it cool off several times during a flight (it's easy to guess the motor temp by the temp of the metal "shielding" around them!). Anyway, the motors come out easily and must be easy to replace. If you read my above post, it seems that after a bit of use the blades loosen and increase pitch .... which would slow them down & overload the motors (the higher pitch and slower blade speed being inefficient Rn-wise, and the slower motors being inefficient electrically (too-low back-EMF!). So that might be why the motors might get TOO hot, but I find when it starts to "wobble", that I need to either tighten the blade holders or reduce their pitch, using the "wobbliness" as a tuning criterion. And I continually use expensive model train lube on everything moving, also reducing the need to unduly load the poor motors.

just love my heavy harley ... I mean heli.


*when the rotating edges go from being one line to being RAZOR-sharp visually, the rotation speed increases dramatically for the same setting .... like from trying to run on sand to running on asphalt! Vrooom .... scream ....!
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Old Aug 26, 2010, 07:49 AM
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hmmmm ....

Well, I still think the 5888's are lovely and really enjoy flying them, but judging from the posts of others, this is a successful low-cost 4-ch heli mainly for those experienced heli-model fliers who don't mind "tweaking", adjusting & maintaining them (as req. for any "real" heli!).

My previously posted "tips" incl. maintaining lower pitch & precise tracking, etc., via blade-holder adj., and using high-quality lube on every moving part!

Lee
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Old Aug 30, 2010, 10:45 AM
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after 70+ flights ....

OK, actually 70+ full-chg/use-cycles, since many full-charges were used to experiment with & adjust the rotors, etc., my daily*-use not-at-first-perfect 5888 is still going strong! And although it hasn't had any real crashes, the blade-holders, etc., have been twist-changed and/or hand-bent a lot**. That includes coning angles, pitch changes and looseness/tightness!

I bought two of these cheaply, put the "perfect" one away as a spare and used the "bad" one to "tune", experiment and learn with. By reducing the coning angles and tightening the blades I greatly increased its inherent stability while sacrificing some speed & agility ["You get Nothing for Nothing" > Physics!]. This made re-leartning my 4-ch heli skills a lot easier and safer, given the very limited airspace I had to use!

So, after over 70 chg/use-cycles and a LOT of flying, learning & experimenting, I took out, flew & used the "perfect" one as a reference to change the much-used one back to "normal" (original). It not only wasn't really the "worse for wear", with ~95% of its original LIPO capacity (based on charge-time using the included 110v/220v digital [controls v/a using micro pulses] house-current wall-charger), but could still fly as FAST (or faster, with a realistic scale visual speed of ~250 KPH/ 150 mph!) and as nimbly as the unmodded/untouched "perfect" one!

WoW! Cool "real"*** heli!

Lee



*OK, it does seem as if I have a new addiction ....!

**IMPORTANT: I did manage to strip the blade-holder threads by twisting with the screws in! (repaired by building up underside "threaded nuts" using CA gel > works!). It turns out that simply renoving the screw but leaving the blade in makes it easier to twist/bend and doesn't strip the threads!

***It flies solidly like a large R/C heli (and makes wonderful sounds, incl. whistling tip-airflows and low freq. downwash "roars"), requiring quality lubing, "tuning" & razor-sharp! tracking like any real heli!
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Old Aug 31, 2010, 03:22 AM
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thinking of getting this. what is the next best (and economical) 4ch, RF or IR?

was looking at ebay... there's ALCON, anyone tried that? seems more stylish.

also how does this compare to Nine Eagles SOLO PRO?

thanks. newbie post.
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Old Aug 31, 2010, 07:38 AM
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Why are you guys looking for a cheap no-name 4ch IR at 50$ when you can get a Nine Eagles for pretty much the same price or a Esky for a little bit more, both of them not IR, so you can fly in the sun...?
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Old Aug 31, 2010, 07:55 AM
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All of my 5888's have impeccable 2.4 gHz R/C systems and fly wonderfully outside. And G.T. Models has a good rep, with many items, most in the "hobby class" and much larger than the 9008 and 5888. I think theyr'e by far better, for the money, than any of the others ....!

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Old Aug 31, 2010, 10:35 AM
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Ahaha forgot that the TopToyExpress was 2.4ghz... :P
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Old Aug 31, 2010, 01:38 PM
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where to buy this cheap other than eBay? thx.
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