HITEC SERVO FAILURE....PLEASE READ!!  
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HITEC SERVO FAILURE....PLEASE READ!! - 4/16/2005 2:15:15 AM   
VKerster


 

Posts: 266
Joined: 12/14/2002
From: highland, MI, USA
Status: offline 		TO ALL WHO READ THIS POST... ATTENTION! THE NEW HITEC 635 HIGH TORQUE SERVO WITH THE KARBONITE GEARS HAS A MAJOR GEAR BREAKAGE PROBLEM. I FITTED MY NEW TOP FLITE GIANT P-51 WITH A SET OF THESE SERVOS AND AFTER 3 FLIGHTS BROKE ONE ON THE RIGHT ELEVATOR, AND AFTER 7 FLIGHTS BROKE ONE ON THE LEFT ALERON. THE BOX THE SERVOS CAME IN SAY THE SERVO CAN BE USED ON UP TO 1/4 SCALE PLANES, THE P-51 IS 1/5. THE ELEVATORS HAVE ONE SERVO ON EACH ELEVATOR. THESE ARE BRAND NEW OUT OF THE BOX UNITS. I CONTACTED HITEC, THEY OFFERED TO SEND ME A NEW GEAR SET, BUT DIDN'T OFFER A EXPLANIATION OR REFUND. BOTH FAILURES COULD HAVE BROUGHT THE PLANE DOWN, IT'S A MIRACLE THE PLANE DIDN'T CRASH. HAVE UP GRADED TO THE HITEC 645 ULTRA TORQUE WITH METAL GEARS AND THE PROBLEM APPEARS SOLVED. ANYONE OUT THERE WITH INPUT, FEEL FREE TO POST OR E-MAIL ME, IN THE MEANTIME, BE CAREFUL!!!!!!!!!!

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VKerster
       Post #: 1

RE: HITEC SERVO FAILURE....PLEASE READ!! - 4/16/2005 2:21:20 AM   
t_burley



Posts: 2578
Joined: 1/11/2002
From: Bakersfield, CA, USA
Status: offline 		there is another thread on this site somewhere already about these gears.
apparently Hitec has changed there info on these, and they are NOT for
up to 1/4 scale planes. they limit them I believe to up to 10-12 lbs

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Todd
Meister, Aero Acc., Sierra, Glennis, Get Stencils, Shinden, Warbird Colors, Fliteskin customer

(in reply to VKerster)
       Post #: 2

RE: HITEC SERVO FAILURE....PLEASE READ!! - 4/16/2005 2:41:38 AM   
MarkShapiro


 

Posts: 664
Joined: 2/1/2002
From: Miami, FL, USA
Status: offline 		I have been flying the 645's on my 1/5 scale warbirds with no problems. Very reliable. Glad you did not crash your Stang.

(in reply to t_burley)
       Post #: 3

RE: HITEC SERVO FAILURE....PLEASE READ!! - 4/16/2005 3:02:03 AM   
DaddySam


 

Posts: 977
Joined: 7/27/2003
From: Pullman, WA, USA
Status: offline 		Hitec told me that they do not recommend using them on anything over 12 lbs with one servo per flight surface. I bought some with my larger planes in mind, and now have put them on my smaller planes. I feel like I'm paying $30 for a Futaba 148! I'm using the big Hitec 700 and 705 on my elevators and rudder, and will most likely use some Hitec 645's on my ailerons.
Sam

(in reply to MarkShapiro)
       Post #: 4

RE: HITEC SERVO FAILURE....PLEASE READ!! - 4/16/2005 3:49:11 AM   
fw190



Posts: 793
Joined: 1/1/2002
From: Burbank, CA,
Status: offline 		There good for nothing unless you want high torques on your 40 size arfs. So I returned all my 635 with 645. Thanks for these posts as it helps me and a lot of people.

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www.VicRC.com

(in reply to DaddySam)
       Post #: 5

RE: HITEC SERVO FAILURE....PLEASE READ!! - 4/16/2005 4:45:19 AM   
Fighterpilot



Posts: 445
Joined: 12/20/2001
From: Kenner, LA, USA
Status: offline 		You guys are absolutely correct, Hi Tec recommends the karbonite geared servos for up to 12 lbs aircraft. Now, it makes a lot of sense to design and build a 130 oz/in servo that can be used only on a 12 lb airplane. Somebody at Hi Tec messed up here, big time, and they are now trying to cover their six. I purchased 8 of them with the idea of using them in a new Jack Devine Models Bearcat powered by a 4.2 Sachs gasoline engine. Now, I have to use them on throttle and retracts since Hi Tec's remedy is simply to say, "Sorry about that." So, it's back to the 645MG Hi Tec servos and the Futaba 3305's.

(in reply to fw190)
       Post #: 6

RE: HITEC SERVO FAILURE....PLEASE READ!! - 4/16/2005 4:50:46 AM   
t_burley



Posts: 2578
Joined: 1/11/2002
From: Bakersfield, CA, USA
Status: offline 		amen to what Krum said. I use those same servos (645MG's) great servos!

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Todd
Meister, Aero Acc., Sierra, Glennis, Get Stencils, Shinden, Warbird Colors, Fliteskin customer

(in reply to Fighterpilot)
       Post #: 7

RE: HITEC SERVO FAILURE....PLEASE READ!! - 4/16/2005 4:59:53 AM   
Waco


 

Posts: 145
Joined: 9/30/2002
From: OH
Status: offline 		They also do not recommend them on any plane with a gas engine. The vibration can cause the gears to break. I contacted them and they said if you want to use a gas engine to use metal gear servos.

(in reply to t_burley)
       Post #: 8

RE: HITEC SERVO FAILURE....PLEASE READ!! - 4/16/2005 1:05:58 PM   
VKerster


 

Posts: 266
Joined: 12/14/2002
From: highland, MI, USA
Status: offline 		THANKS, EVERYONE FOR THE INPUT. HITEC IS BOARDING ON FALSE ADVERTISING WITH THEIR 635'S AND NEEDS TO STEP UP TO THE PLATE AND ADDRESS THIS SITUATION.
IT'S A BEAUTIFUL DAY HERE IN MICH, TIME TO RIP UP THE SKY.................

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VKerster

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       Post #: 9

RE: HITEC SERVO FAILURE....PLEASE READ!! - 4/16/2005 2:50:53 PM   
Edwin


 

Posts: 3381
Joined: 2/8/2002
From: Leander, TX, USA
Status: online 		DAMN!!!! I just bought 8 to put in my TF giant P-47. I just know the hobby shop isnt gonna take them back. Shoulda know it was too good to be true.
Edwin

(in reply to VKerster)
       Post #: 10

RE: HITEC SERVO FAILURE....PLEASE READ!! - 4/16/2005 8:56:18 PM   
a65l



Posts: 1481
Joined: 12/7/2003
From: va veach, VA, USA
Status: offline 		I've got these in a Goldberg Sukhoi (72 inch) and so far have had only the greatest of luck with them. I just got 4 more to use on my KMP Sea Fury, but that plane should come in under 12 lbs. I guess the Karbonite is a bit more brittle than they thought.


Andy

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In God I trust.
All others pay cash.

(in reply to Edwin)
       Post #: 11

RE: HITEC SERVO FAILURE....PLEASE READ!! - 4/17/2005 5:08:47 AM   
KatanaMadMan



Posts: 123
Joined: 5/17/2004
From: Brisbane, AUSTRALIA
Status: offline 		Thanks guys, I was just about to buy 8 of these things. I'll definately go with 645's now. Rather be safe than sorry. I thought these karbonite gears were suppose to be 4 time stronger than nylon. Maybe their 10 times more brittle too.

(in reply to a65l)
       Post #: 12

RE: HITEC SERVO FAILURE....PLEASE READ!! - 4/17/2005 4:27:14 PM   
F4u5



Posts: 1819
Joined: 1/19/2002
From: Apple Valley, MN, USA
Status: offline 		I can't believe they replaced the good old 605 with the 635 Karbonite. I knew when I saw them and read about them that they could not be as good as the old 605. Mainly a newer servo with less torque, but claimed stronger material....just didn;t make sense to me. I have argued the point with Hitec for 2 straight years at Toledo. They continue to say it is a better and stronger servo than the old 605. Then you read about all of these problems. And:

Initially, the top of the servo gear shaft, where the servo arm attaches, was breaking off. They contributed that to supplying too short a screw for securing the control arm (8 mm). So, they went to a 10 mm, saying that it restored the strength to the shaft. I don;t know if that was or fixed the problem.

Now, in the last RC Report, I read of more gears breaking. They cintributed this to people using blue loctite to secure the servo arm shaft screw, saying that it attacks and weakens the material, causing it to fail.

VKerster, did you fit in to either of these catogories above? I am curious, as I agree it is a poor servoe, exspecially compared to the old 605 it replaced.

I ran 605's for the last 12 years, in planes weighing from 20-50 pounds, and never had a problem with them. In fact, I have used Hitec exclusively for the last 12 years, and have never had one go bad or break in typical flight. I have supported them vigorusly based on my experience. Now, I have shyed away from the 635, and appears I will be doing so in the future. It is too bad they may have skimped on this servo, and it may cost them in the end. I am disappointed to hear about this on the new 635, as the 605 is no longer made. However, I'm, glad your plane survived. Thx for the wake up.

_____________________________

Where's my glue?.......I gotta build.

(in reply to KatanaMadMan)
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RE: HITEC SERVO FAILURE....PLEASE READ!! - 4/17/2005 4:42:41 PM   
SJN



Posts: 4390
Joined: 9/28/2002
From: Copenhagen, DENMARK
Status: offline 		Im only using the karbonite servos in my boats........ here is my flying buddy`s servo.



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Sonnich Johannesen

(in reply to F4u5)
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RE: HITEC SERVO FAILURE....PLEASE READ!! - 4/17/2005 5:50:03 PM   
bentgear


 

Posts: 2742
Joined: 3/25/2002
From: Brandon, MS, USA
Status: offline 		SJN, that looks like the fialure from either a 8 mm screw or from using locktite on the threads. Using the 10 mm screw lets it almost bottom out getting more surface, using locktite reacts with the Karbonite making it very brittle in the area it was applied.


From what I have seen of the gears they are able to take a pretty good load in the air, even doing 3D, but if you bump the controlled surface pretty hard getting it in or out of storage you may have just set yourself up for failure.

Ed M.

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Did you bother to Read The Fine Manual yet?

(in reply to SJN)
       Post #: 15

RE: HITEC SERVO FAILURE....PLEASE READ!! - 4/17/2005 9:11:25 PM