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Old Aug 31, 2011, 10:43 AM
Registered User
Zurich
Joined Apr 2006
3,989 Posts
food for thought ....

from the "Are 3-ch helis meant to be repaired?" thread >

Quote:
Originally Posted by dafremen
Get the cheap heli. Fix that mofo. Fix it again and again and again. First you'll be fixing it..soon you'll understand enough to want to try to modify it. Eventually, you'll be building your own from scratch.


Quote:
Originally Posted by xenophobe View Post
That's the first thing I wanted to do after flying it a few times... and then it was done. My s105 flies so much better stripped down. It flies longer, more precisely and is a lot more fun.
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Old Aug 31, 2011, 01:22 PM
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cosvel's Avatar
España, Comunidad de Madrid, Madrid
Joined Aug 2011
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Quote:
Originally Posted by xlcrlee View Post

Enjoy your life and the helis of your choice!


Lee
Do not hesitate.

cosvel.
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Old Sep 08, 2011, 10:57 AM
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5888 fun ....

Some of my "super-tuned" 5888s are SO "hyper" that they must be very carefully flown (they act in "slow" mode, which is too boring for me to use in any case, like most o.o.t.b. 5888s do in HIGH mode!) to avoid starting flight-destructive destabilization > they can start to oscillate almost too quickly for human reflexes to correct!). But, with the proviso to make careful inputs (like an F1 racecar) they are exciting to fly. [OK, exponential Tx stick input would be nice!].

So I now found out that the extra "agility"/input-response allows flying vertical-axis rotations while circling very fast to almost become EASY ....! [While circling the room at reasonably high speed -- one room-wide circle in ca. 2.5 sec -- making several axis rotations, as would an iceskater, requiring constant rt-stick/swashplate movement]

Lee
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Old Sep 09, 2011, 10:54 AM
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STRANGE but true > weird "fix"

Revenge of the Electricicles

One of my older 5888s (mfd. early 2010, now on its 4th motor-set and 2nd servo replacement) suddenly stopped working. That is, when switched on, the LEDs would blink, but no servo or motor response or ftn.

I tried everything I could think of .... almost.

Then I realized thet the total system is very complex, with MANY temperature-sensitive components plus software with which they interact. So I used a hairdrier to heat the exposed rear of the PCB (to which face is attached several microprocessors and the piezoelectric "gyro"), being careful not to seriously heat the very thin fwd "cabin" enclosure.

It worked!!

Then after some time, with the heli having cooled off, I switched it off & on and tried a re-start ..... nothing! Again, lights but no action. So once more I heated the PCB and it worked again. Hmmmm. So THIS time, with the heli still switched on, I put it in the refrigerator to cool, took it out after a while, turned on the Tx, and it was still working (motors & servos). Now still cooled well below room temp, I turned it off & on, and successfully re-started.

So far, it's still working properly when turned on (by the switch, not flattery, etc.), but at least I now know how to "kick-start" it if needed. And the hairdrier-fix is much gentler than actually kicking it! [I was never tempted to do so, as it does have valuable parts I can use]


Lee
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Old Sep 11, 2011, 09:04 AM
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Zurich
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re: "hairdrier-fix"

That heli seems now "cured": no more weird issues.

I note that the on/off switch has multiple connections. Additionally, I often lube the linear servos, and the right one is almost over the switch. Thus it's possible that I managed to bathe the switch in lube and some of the contacts were disrupted.

So it was perhaps the hot "wind" of the hairdrier (the German name for "hairdrier" is almost the same as that of a European hot dry wind phenominon, similar to the USA's Santa Ana winds) that blew away lube from the switch. And the heat would allow the lube to flow more freely as well.

Could be ...
.

Nonetheless the "hairdrier-fix" is simple and works: it's something good to remember.

Lee
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Old Sep 11, 2011, 09:29 AM
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blade stiffness re: "tip-play"

One of my 5888s had a difficulty turning right after I put in one of the new (but seemingly weaker) gray-topped left motors, replacing a worn-out white-topped one. I had been using my now "standard" tip-play set-up > 4mm upper rotor blades / 3mm lower, but had recently changed blades to more longitudinally flatter ones to de-sensitize the input response, as it has a much greater-than-ususal servo throw!

Now I noticed that the upper blades were a lot softer than the lower, allowing them to incr. pitch with incr. RPM much moreso than the lower [fwd-swept blades!!] .... resulting in excessive left torque! And it would descend rotating to the right (instead of the normal left rotation descent), indicating that the upper rotor was decreasing lift -- relative to the lower rotor -- more than normal w/ reduced RPM.

After I simply installed stiffer upper blades, better matching the lower blades, the problem disappeared .... [decreasing the upper rotor tip-play and/or vice versa for the lower, etc., might also have worked, but I have collected many blades for just these purposes].


Lee
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Old Sep 13, 2011, 03:28 AM
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España, Comunidad de Madrid, Madrid
Joined Aug 2011
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My 5888 is in the air again.... XDD
I have made a little ¨tuning¨ reducing weight, now with the new 240mAh battery included the weight of my heli is 43gr... flies very very well... I will try your set up of the blades to see how it works... I want more speed!!

Testing voltage...


The nine eagles charger mod, charging a new battery side by side of a solo pro battery...


And here the battery after a little modifications..




Will make some pictures of the tuned heli later...

Regards.
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Last edited by cosvel; Sep 13, 2011 at 03:41 AM.
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Old Sep 22, 2011, 08:14 AM
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Zurich
Joined Apr 2006
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"Yee-Haw"-factor ....

One of my older 5888-B's is just slow, compared to my other 5 HOT ones [with the first, original WHITE-topped left motors!]. Because its PCB drives servos [I've changed 2 in it so far w/ same limited output result] only about half so far (1/2 "throw") as most 5888s, it flies "slow", like all the 5888s I've seen in posted videos! [NOTE: I purposely flew the blue one slowly in my "Birthday Party" vid because of the combination of the confined space and the many people who knew me, not wanting to crash into friends, right?].

Anyway, flying this "slow"[-er] 5888 is nice and fun .... but it definitely lacks the F1/ Pylon Race "Yee-Haw"-factor of my other HOT ones!


Lee



NOTE: I didn't buy the 7th 5888 now from Marcel (as a spare), because he found had no more "older" ones with the far more powerful white-topped left motors.
I'll wait to see in whatever next shipments he gets if G.T. Model improves their current [word-play!] motor selection! > only TWO of the TWENTY gray-topped left motors I've (flight!) tested are even close to "super", and some were downright pathetic. Otherwise I am done with buying or recommending this item as a potentially super-performing low-cost product! The controlled HOT performance [like CP/ SR, w/o white-knuckle stress!] comes from its extra weight, extra POWER & stability .... but without lots of power, it just doesn't "get it" for me ....
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Old Sep 23, 2011, 09:31 AM
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"Death Turn" > in reverse outside!

One of my hot little 5888's survivied a "high-up" death-spiral tumble unscathed, bouncing safely in the soft grass yesterday. But the event took me by stupid surprise, as it happened in reverse to the conventional so-called "Death Turn" >

Although many pilots (and even some engineers!) who are not familiar with all the details of Einstein's General Theory of Relativity [not the "Special T. o. R."] will "argue" otherwise, there is in fact a real difference between upwind and downwind turns. That is because not everything in the universe is co-relative, and an aircraft is is the massive Earth's momentum frame-of-reference, not that of the thin, lightweight layer of air in which we live and fly! Thus, as an aircraft turns downwind, it is still "tied" to the Earth and briefly experiences a lower relative airspeed. Then the aircraft's pitch (= speed!) stability lets it "catch up" again to the wind.

For an aircraft with lots of drag AND lots of compensating power, the "catch up" happens too quickly for mere mortals to notice. But this effect can be significant for low-powered aircraft, incl. "slow" micro coax helis.

High-drag WWI aircraft often stalled & crashed when turning downwind on final, and so came the term "Death Turn". Albatrosses actually use this subtle effect in what's called "Dynamic Soaring* to effortlessly cross the Pacific!

Yesterday while zooming one of my 5888's around a small park, even outrunning some little kids while leading them around flying sideways just in front of them [HOT 5888!], I accelerated fwd upwind to ca. 15m high and started a [relatively, for a tiny coax] high-speed left banked circle. As soon as it came around upwind again it tightly spiralled down before I could correct (no damage, except to pride).

5888's (and similarly configured 4-ch coax´s) go slower, need more rt. bank input (stick or trim) and often want to descend in RIGHT banked turns. Conversely, they can easily speed up and spiral-in when making fast banked left turns. That is because in a banked left turn the less efficient upper rotor (has to drag the flybar!) speeds up (to yaw left) to more lift-efficient Rn's, AND the lower rotor gets more advancing blade lift on the rt. side, incr. the turn!

The reverse happens in a banked right turn, with the aforementioned results.

So when my little heli turned fast again into the wind, the momentary airspeed increase it encountered enhanced the "Death Spiral" ("Toilet Bowl"!) effect .... and down it went!

This upwind caution for such coax's (not dual swash, for ex.) is opposite to the "normal" downwind turn effect, such as an SR might experience. However, when I sorted out what happened and why, I simply eased up on the fwd & left stick input during the upwind portion of a "high-speed" banked circle ....and the little heli flew nicely without plummeting ....


Lee
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Old Sep 30, 2011, 12:49 PM
Power-line attraction pilot
United States, MA, Natick
Joined Jun 2011
520 Posts
So is the consensus that a 240mah battery is in fact an upgrade for this small 5888 heli, increasing flight time, etc..?

What is currently the cheapest vendor for these small lipo packs?

I plan to add a tiny video transmitter and micro camera to the 5888 with a 50mah lipo pack powering the AV. This AV setup alone will weigh about 5 grams.

I would like to increase flight time as well, and figured the 240mah main battery replacement would do just that, but hobby king states that the 240mah battery is about 5.9 grams on its own. Am i getting too heavy here?

Any recommendations on shaving weight on the 5888?
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Old Oct 01, 2011, 03:27 AM
Power-line attraction pilot
United States, MA, Natick
Joined Jun 2011
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No pointers regarding weight loss and/or battery upgrade?
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Old Oct 01, 2011, 07:40 AM
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Zurich
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Quote:
Originally Posted by caall99 View Post
No pointers regarding weight loss and/or battery upgrade?
Removing the 3 LEDS and ALL their wiring, plus the translucent white cowl cheeks will save some weight. But a much greater benefit comes from TUNING, TRACKING and adjusting the 5888, equivalent to losing 30 - 40% of its weight [which one cannot really do by removing essential parts!].

I strongly recommend NOT putting in a larger LIPO >


1. You must still fly for only a few minutes at a time to allow the overworked motors to cool, whose job is made worse by
2. the increased WEIGHT and
3. increased current flow.

A better solution might be to just find another heli to suit your needs ....

Lee
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Old Oct 03, 2011, 11:06 AM
Power-line attraction pilot
United States, MA, Natick
Joined Jun 2011
520 Posts
What are the dimensions of the 5888 motors? Diameter, length, exposed shaft length, shaft diameter, mounting hole distance and size etc...

If someone could provide me with that info I would really appreciate it!
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Old Oct 04, 2011, 12:08 AM
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man1024's Avatar
Joined Oct 2011
364 Posts
Will this lubricant work?

Atlas-Model-Railroad-ATL190-Gear-Lubricant

http://www.ebay.com/itm/Atlas-Model-...708#vi-content
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Old Oct 04, 2011, 10:30 AM
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Quote:
Originally Posted by man1024 View Post
Will this lubricant work?

Atlas-Model-Railroad-ATL190-Gear-Lubricant

http://www.ebay.com/itm/Atlas-Model-...708#vi-content

If you "enlarge" the photo in the following link and read the product label you will note the word "platic" and compatible, so my best guess is that it is likely also PLASTIC compatible [wink] >

http://www.horizonhobby.com/Products...?ProdID=ATL190



L
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