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Old Aug 03, 2012, 09:26 AM
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why plastic hinges = ruined product!

To Review:

The first two 5888s I bought flew super, really, but the 3rd & 4th (as spares to store for the future) flew very poorly when tested. After a lot of experimentation (and some killed 5888s), I tenatiousLee found how it was possible to make every 5888 super! [approximately only 10% of them work well out of the box!]

Making them super [the only way I'd have one of these!] requires access to a lot of spare parts (esp. blades + gears to match/mate perfectly) .... and the original aluminum-plate hinge system which can be precisely adjusted! [every 5888 needs diff. adjustment!]

Months ago the factory shipped my "distributer" Marcel these plastic hinges. I tried them, found what you did and foolishly assumed they were for another model intended for 1st-time "pilots".

But, to be fair, I have now taken one of these plastic hinges, assembled a blade into it (the brass bushings don't fit and it looks like one will have to live with the extra looseness, which may be OK), adn used a hairdrier to help "permanently" bend the coning angle down and also change the pitch (as a test > I'd NEVER fly with these hinges). This is a potentially dangerous procedure, as the thin blades have a lower melting point than the hinges and can easily be ruined in the process. Since it seems best to adjust with the blades in, successfully masked the one I used with my fingers, heating the entire length of the hinge.

So far the bend seems to stay ....but my experience with this type of plastic suggest it will have to be re-done again & again with use over time. You can find out [wink].


Given G.T. Model's very poor QC, without the alu-hinges, I wouldn't buy any of these any more. If I bought one thinking it was like the photo with alu-hinges and they sent it with plastic ones, I would return it! [false advertising is illegal]


Further, I suggest everyone write their distributer and the factory
["hongxintoys factory" <sales-anna@hongxintoys.com> ]
telling them to at least make the original aluminum hinges [+ parts!] available on request, even if the cost seems a bit higher than the factory thinks might be user-acceptable.


[To save money, Chinese factories have a long history of too-often cutting the WRONG corners ....!]



Lee
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Old Aug 05, 2012, 10:16 PM
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Lee:

I tried to buy the main blades with the washers and the seller told me he only had "the new blades without washers" Do you know any place were I can buy the old set? At Toptoyexpress they're out of stock. Anyway I will try to manufacture some washers. Dou you know the thickness of the original washers? I made a couple from a vaccum formed blister and it seems too thick. I will try with something thinner this week. This 5888 is a present for my son and it doesn't fly very well out of the box. The tracking is very bad. About 1mm difference in both blades set. Also the landing gear is bent, the plastic parts. Is it ok if I heat it fitted in the helicopter? Sorry for all this questions, I am running out of time. The present is for this Sunday!
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Old Aug 06, 2012, 04:46 AM
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sorry ....

I first read your post today!

Bushings: I would find some brass tubing at a hobby store (take along a blade bolt and a blade for I.D., O.D, although it should be easy to open the blade holea bit if needed). Roll-cut it with a shart hobby knife and leave a paper-thin length longer than the blade hole so it can "rock"; gile to best length.


You should be able to use the hairdrier with blades on the heli if you loosely wrap the blades with paper and "close" with some tape. Remember to use a small piece of tape first at the root of each blade separately to test for pitch equality, then at each tip to work on the coning angle of each. I may be wrong: the hub plastic seems to hold the heated bends very well and the adjustment may last a long time in use.

Also, I think it's OK to use the "old" blades w/o bushings with the plastic hub. And the plastic hub still allows some screw adjustment for "tip-play".

Good Luck!,
Lee
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Old Aug 06, 2012, 02:19 PM
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Lee:

Thanks for your answers! Yes, the blades can be adjusted but I can't get the 3mm or 4mm tip-play you advice. I made some washers (prehaps the best name is bushings, I want to be sure we are talking about the same thing) 3mm circle with a 2mm hole in the middle. From another blister, I will test it later. Forgive me if this is already described but when you say "use tape at the root of each blade to test for pitch equality" I don't unerstand how it is done. I used tape at the tip to see the tracking (leaving some tape passing the blade tip) and I noticed the tracking changed, the I added more tape in the middle of the same blade and even less difference. Does this mean the blade's weight is different? I don't have a scale that can measure that small difference.
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Old Aug 07, 2012, 12:07 PM
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I tested the washers, but I detected heat in left motor. I flew a while without the washers when the motor cooled and it seems that the heating is gone. I also added some tape to the blades to improve tracking. I don't want to spoil the hinges before my son has the chance to fly the heli at least a couple of times! Is it posibble that the washers are increasing pitch and therefore the engine is being forced? I will fly a full charge without the washers to compare checking every 30 sconds. I will let you know how it goes.
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Old Aug 08, 2012, 08:17 AM
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1. If you have the "old" blades and the "old" alu-hub system, you must use the bushings. Make them as I described, and file down to the precise height above & below the blade to allow the correct tip-play rocking. The old blades do not seem to need the bushings in the plastic hinges, even if they seem loose in the later/horizontal plane > they will pull outward and be laterally tight when spinning.

2. Use a ca. 1 inch length of clear office/home 3M adhesive tape taped on the underside of the root section TRAILING EDGE of each blade, first one, THEN the other, with half of the tape, maybe 1/3 inch, extending rearward from the trailing edge of that blade. Do NOT let the tape extend outwardly, away from the hub, beyond the tip!! Then run the heli in your hand and observe the tracking. Remove the tape and place it in the same position on the other blade and observe the tracking. See which blade was most helped by the extra lift of the tape. REMOVE the tape: do not fly with the tape!!

THEN increase the pitch of that blade and/or reduce the pitch of the other blade. Recheck for tracking.

If the blades are still "off", place the tape on the trailing edge of the TIP of one blade with the tape is diagonally tilted viewed from above, so that ca. 1/3 inch extends rearward from the TIP of the trailing edge of that blade, tapering down to ca. ZERO at the part of the tape closest to the hub. Repeat tracking observation as above, one blade at a time.

The blade most helped by the increased lift only at its tip needs more coning angle and/or the other blade less coning angle. REMOVE the tape after adjusting the coning angles.

Repeat both procedures until the blades are perfectly tracked. Note: this may eventually take many hours .... but it always works.

Good Luck,
Lee
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Old Aug 09, 2012, 07:21 AM
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Thanks Lee! It is much more clear now. I will try this when get the alu hinges. Have you tried using a plastic tube (i.e the inside of a water spray) instead of the brass tubing? I am trying to find a brass tubing of this size and it is dificult. I will let you know how it goes. One last thing. Sometimes there is a micro cut in the motor(s). It seems like they stop spinning for a very short time. Is this related to their heating?
Thanks again for your advise and sharing your knowledge.
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Old Aug 10, 2012, 08:34 AM
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Quote:
Originally Posted by diegogonz76 View Post
Thanks Lee! It is much more clear now. I will try this when get the alu hinges. Have you tried using a plastic tube (i.e the inside of a water spray) instead of the brass tubing? I am trying to find a brass tubing of this size and it is dificult. I will let you know how it goes. One last thing. Sometimes there is a micro cut in the motor(s). It seems like they stop spinning for a very short time. Is this related to their heating?
Thanks again for your advise and sharing your knowledge.
1. You can first "practice" using a hairdrier on the plastic hinges. Just wrap the blades with paper as insulation.

2. Usually the motors momentarily stop or shuuder because there is a sudden change in the blade settings, as one gets looser or shifts.


Use your lower lip as a temperature guage to test the alu-cladding around each motor. Because the aluminum is not touching the motors, the cladding gets MUCH less hot and gets hot LATER than the motors: so as soon as one of them feels slightly warm, like a comfortable bath .... immediately STOP flying and let it cool! The refrigerator also helps.


L
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Old Aug 14, 2012, 10:32 AM
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Alu hinges arrived! First of all I have to thank you because this thread is what made me buy this heli. My son is really very happy whith it! He crashed the heli several times, even to the point where it turns off for protection. And it is still flying just like the first time. With all the problems I described but no extra harm. Except for the tail light that is not working any more. I am trying to find this small brass tube with no luck so far. Hobby shops are far from where I live. I will try online. I also thought that perhaps I can use a small plastic tube, have you tried that? I'll let you know how everything goes!
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Old Aug 16, 2012, 06:17 AM
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Quote:
Originally Posted by diegogonz76 View Post
Alu hinges arrived! First of all I have to thank you because this thread is what made me buy this heli. My son is really very happy whith it! He crashed the heli several times, even to the point where it turns off for protection. And it is still flying just like the first time. With all the problems I described but no extra harm. Except for the tail light that is not working any more. I am trying to find this small brass tube with no luck so far. Hobby shops are far from where I live. I will try online. I also thought that perhaps I can use a small plastic tube, have you tried that? I'll let you know how everything goes!
The tailboom, like all the metal parts except the screws & bolts, is ALIMINUM.

If you use plastic, remove the tail LED and also make the tailboom longer to keep the same very slightly fwd balance point as before!

L
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Old Aug 21, 2012, 01:34 PM
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Hi, as I told you before english is not my native language and I made a mistake when writing. I am trying to replace the brass tube for plastic for the blade hinges. The tail is intact, only the led not lighting. I see what you mean now that I have the hinges. Without this tube the blade hole is touching the screw. Another problem I have is that the blade screws are too small. I bought the hinges and they came with the small screws for the center of the hinges, not for the blades. The screws I have from the plastic hinges are too thin for the alu hinges. Also the head of the inner shaft is different. The hole in the upper hinge is smaller in the alu hinges. So I am trying to find a spare part for this shaft. Can you tell me if that is all I need? I mean if that spare part only is enough. I ask you this because I've seen the shaft and the upper blades already assembled. Perhaps I should buy that instead. Thanks again for you help!!
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Old Aug 22, 2012, 05:06 AM
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Quote:
Originally Posted by diegogonz76 View Post
Hi, as I told you before english is not my native language and I made a mistake when writing. I am trying to replace the brass tube for plastic for the blade hinges. The tail is intact, only the led not lighting. I see what you mean now that I have the hinges. Without this tube the blade hole is touching the screw. Another problem I have is that the blade screws are too small. I bought the hinges and they came with the small screws for the center of the hinges, not for the blades. The screws I have from the plastic hinges are too thin for the alu hinges. Also the head of the inner shaft is different. The hole in the upper hinge is smaller in the alu hinges. So I am trying to find a spare part for this shaft. Can you tell me if that is all I need? I mean if that spare part only is enough. I ask you this because I've seen the shaft and the upper blades already assembled. Perhaps I should buy that instead. Thanks again for you help!!
Yup: buy that instead. And in the meanwhile, try hairdrier-heat twisting/bending the plastic hinges! (just shield the blades: I had NO problem with that).

L
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Old Aug 22, 2012, 07:37 AM
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Ok then. Is it possible to apply heat without the blade? I'm affraid of melting it!

Also can you tell me if the metal balance bar from my plastic hinges model fits in the old inner shaft? I think I will have to buy things separately.

Thanks again!
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Old Aug 23, 2012, 03:47 AM
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Quote:
Originally Posted by diegogonz76 View Post
Ok then. Is it possible to apply heat without the blade? I'm affraid of melting it!

Also can you tell me if the metal balance bar from my plastic hinges model fits in the old inner shaft? I think I will have to buy things separately.

Thanks again!
You have to leave the blades in to know how much to twist/bend the hub!

I had NO problem merely shielding the blades with my hand! But it is easy to wrap the blades with paper, even soft "tissue" or even "utility/kitchen" paper, and hold closed with a bit of tape: i've done this many times and NEVER melted a blade [even when experimentally re-forming a blade's pitch, camber or washout ... and then easily REVERSING the procedure].

Just use a normal electric hairdrier for a few seconds, and proceed in small steps.

Do NOT use a heat gun ....!


Lee
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Old Aug 23, 2012, 10:42 AM
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OK then, I will try it. I will try to post a picture because I saw something I think is wrong with the swashplate, I think the problem is in the outter axle, the one that drives the lower blades. It has a plastic ring with a screw and the swashplate is touchng this plastic, so when the blades spin the plastic lifts the swashplate when the screw is in the tail direction. I tried to change the position of the blades or this plastic ring but that's not possible because the axle has holes for the screws, so the distance is fixed.
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