Notices
Hitec/MultiPlex Radios- Ask Hitec Customer Service Ask Hitec/MultiPlex Customer Service your Radio questions here.

Hitec 635 HB use not as originally advertised

Old 06-20-2005, 02:37 AM
  #1  
DaddySam
Thread Starter
My Feedback: (9)
 
Join Date: Jul 2003
Location: Pullman, WA
Posts: 2,221
Likes: 0
Received 0 Likes on 0 Posts
Default Hitec 635 HB use not as originally advertised

I'm sure this has been beat to the death, but there are many of us who bought the 635 HB when it first came out, touted as the replacement for the 605, stronger gear train, etc, who now find ourselves having to buy other servos for our giant scale planes. I think that Hitec, to after-the-fact add a recommendation that they not be used on planes over 12 lbs, essentially marketed a servo as one thing and then changed their minds when the "karbonite" started acting like "kryptonite". Will Hitec take our 635's on trade for a more robust servo, or offer a gear train upgrade to make these "as advertised" (replacements for the 605)? Many of us are fairly happy Hitec servo users, but this whole Karbonite gear fiasco is ticking us off.
Thanks in advance for any consideration you can show us.
Sam Sorem
Old 06-20-2005, 01:31 PM
  #2  
MikeMayberry
Senior Member
My Feedback: (1)
 
MikeMayberry's Avatar
 
Join Date: Jan 2002
Location: Poway, CA
Posts: 3,531
Likes: 0
Received 0 Likes on 0 Posts
Default RE: Hitec 635 HB use not as originally advertised

The 635HB gears are stronger than the HS-605BB therefor they could be used in similar applications. With that said... I would also note that the plastic geared HS-605BB servos are not a good choice for models over 12lbs either; it would be best to go with metal gears like the HS-605MG (old) or the HS-625/645MG (replacement to the 605/615MG).

The 12lb rule was established after we discovered that many people were pushing the applications of the Karbonite geared servos. I've even had people tell me they though they were as strong as metal. The Karbonite material is four times stronger than standard white nylon but still many time weaker than metal.

We apologize if you feel Hitec has marketed these servos as suitable for Giant Scale (over 12lbs) in single servo applications, but if you look at our advertising you will see that we state they are only suitable for G.S. when ganged together. This would go for any non metal geared servo including the HS-605BB.

Mike.
Old 06-22-2005, 09:35 PM
  #3  
Eindecker_pilot
 
Eindecker_pilot's Avatar
 
Join Date: Feb 2003
Location: Columbus, IN
Posts: 706
Received 0 Likes on 0 Posts
Default RE: Hitec 635 HB use not as originally advertised

Mike,

I've got 635HB servos with the Karbonite gears driving ailerons in my 1/4 scale Sopwith Pup. This is a WWI scale, slow flying, biplane. Each 635HB servo drives two ailerons (an aileron on each on the upper & lower wings). This plane weighs approximately 13 lbs. Before I had the 635HB, I was using standard servos with nylon gears (40-45 in-oz torque) and these worked okay - no failures after multiple seasons of usage. I upgraded to the 635HB thinking this would be a more robust servo (thinking I was pushing the limit of standard servo capability).

I've been pleased with the 635HB servo in this application, but now I read that this servo is not intended for giant scale. Is it because of the air loading Hitec assumes is on the servo? Is it because of the weight of the plane? Or is it because of the vibration of the gas engines we use? I ask this because my Pup violates the 12lb limit Hitec recommends, but I know this airplane flies slow enough to only put minimal airloading on each control surface (proven by the prior usage of standard servos).

Given the prior success with standard servos on this airplane & the (so far) successful application of the 635HB, would you still recommend I not use the 635HB servos on a slow flying airplane like the Pup, just because it violates the wieght limit? Balsa USA (the kit designer of this Pup) recommends only that the servos have a minimum of 60 oz-in torque. So, according to Balsa USA, the 635HB would be fine. Should I not use the 635HB in a plane with a gas engine due to the vibration issue?

Thanks
Old 06-23-2005, 10:32 AM
  #4  
MikeMayberry
Senior Member
My Feedback: (1)
 
MikeMayberry's Avatar
 
Join Date: Jan 2002
Location: Poway, CA
Posts: 3,531
Likes: 0
Received 0 Likes on 0 Posts
Default RE: Hitec 635 HB use not as originally advertised

There are many variables and at 12lbs that would be for hard core 3D planes with high flight loads, so a milder plane would not put so much load on the servos. It looks like you should be fine.

Mike.
Old 07-11-2005, 06:24 PM
  #5  
Young-RCPilot
Senior Member
 
Join Date: Mar 2005
Location: GTA, ON, CANADA
Posts: 246
Likes: 0
Received 0 Likes on 0 Posts
Default RE: Hitec 635 HB use not as originally advertised

Will this servo be enough for the rudder on a 90 size Edge 540T that I will be doing a lot of 3D with or should I just put in a HS-645 instead. The plane will be getting a Saito 100 .
Old 07-13-2005, 11:40 AM
  #6  
MikeMayberry
Senior Member
My Feedback: (1)
 
MikeMayberry's Avatar
 
Join Date: Jan 2002
Location: Poway, CA
Posts: 3,531
Likes: 0
Received 0 Likes on 0 Posts
Default RE: Hitec 635 HB use not as originally advertised

We're flying the Extreme Fligh 67" Yak with the same engine with the 6975HB servos with no problems.

Mike.
Old 07-15-2005, 08:12 PM
  #7  
rcwarbirdbuilder
My Feedback: (104)
 
rcwarbirdbuilder's Avatar
 
Join Date: Feb 2002
Location: canton, MI
Posts: 1,130
Likes: 0
Received 1 Like on 1 Post
Default RE: Hitec 635 HB use not as originally advertised

I had purchased 15 Hitec 635 servos to use in my warbirds in the past few months. I had used the 605's for a few years with no problem, out of the 15 635's I had two which would center erraticly and had very litle torque in one direction the other direction was fine, but like I said it would not always center on the same location. I was on the flight line ready for a takeoff on a new Nolson P-51 couple of weeks ago with another New 635's on the elavators, fortunately for me just before throwing the throtle forward I tried the elevators and the left elevator would not go up, on inspection this never used servo had stripped the gears, after this I went through the balance of the 15 servos, on taking them apart I found a loose connection or what I well call a cold solder joint on the black lead which came off with just a touch, so out of the 15 I had 4 confirmed bad servos, I contacted Hitec to get some help such as replaceing these new servos for 645 metal gears and I would pay the difference, anyways I called them twice and found them to be totaly uncooperative and rude! I don't think I well by Hitec again after this and well not patronize them again. Iam back to Futaba 3305 high torque metal gear servos, only thing with Futaba I wish they would get with it and beef up the mounting screws and the horns included with the servos after all it is a high torque servo
Old 07-16-2005, 03:04 PM
  #8  
mglavin
My Feedback: (31)
 
Join Date: Nov 2001
Location: Elverta, CA
Posts: 5,295
Likes: 0
Received 1 Like on 1 Post
Default RE: Hitec 635 HB use not as originally advertised

Geoflying

Is the Nolson P51, a Nosen Giant Scale 102" Mustang? Are your servos the 635HB Karbonites? You are aware these are not replacements for metal geared servos right?

As with any products you'll occasionally have a bad apple, it happens. The servos with the bad gears are likely the result of miss-application and they failed accordingly IMO.

Return the servos to Hitec Service for warranty repair. I’d strongly suggest a different servo for the Nosen Mustang… Metal geared standard size of Jumbos are a good choice for this model.
Old 09-25-2005, 08:40 PM
  #9  
I_Fly_Coolers
Senior Member
My Feedback: (7)
 
Join Date: Jan 2005
Location: winter park, FL
Posts: 424
Likes: 0
Received 0 Likes on 0 Posts
Default RE: Hitec 635 HB use not as originally advertised

I'm just finishing a rebuild of a WWI Junkers monoplane that crashed due to a stalled engine 6 months ago. I had 3 HS635 servos strip the gears, of course from the impact.... I have replaced the gears, but now have been reading about the maximum weight limit for the 635's. My plane weighs around 18 lbs, US Engines gasoline motor, and had been using 1x 635 on each aileron, and one on the (small) rudder. By the way, when I bought these new, 2 servos were bad right out of the box....they would glitch and jitter and not hold center, they were exchanged for another set at the LHS. Does Hitech offer any replacement program so I can buy different servos, maybe pay any difference?
Old 09-26-2005, 10:23 AM
  #10  
mglavin
My Feedback: (31)
 
Join Date: Nov 2001
Location: Elverta, CA
Posts: 5,295
Likes: 0
Received 1 Like on 1 Post
Default RE: Hitec 635 HB use not as originally advertised

Hitec does not offer an exchange and or an upgrade program.

We offer the weight limit as a guide line as many of today’s models have large over-sized control surfaces with minimal or no mechanical advantage. There are many GS models flying with the Karbonites, we simply err on the side of caution as we have know control and or knowledge of specific installations and setups.

How much time did you have on the model prior to the damage?
Old 09-26-2005, 06:45 PM
  #11  
I_Fly_Coolers
Senior Member
My Feedback: (7)
 
Join Date: Jan 2005
Location: winter park, FL
Posts: 424
Likes: 0
Received 0 Likes on 0 Posts
Default RE: Hitec 635 HB use not as originally advertised

The model had about 8 flights on it. I am sure the servo damage was a RESULT of the impact, when the ailerons and elevator jerked against the servos, the accident was not CAUSED by the servos. I tried to stretch a deadstick landing into safer territory and stalled the wing. I decided to simply use these servos elsewhere, and will install some MG ones in the ailerons. Spoke with the LHS today, and they said they have seen problems with stripping the 635 gears only from rough handling (hanger rash) or, for example, if you were to bump an aileron into the ground on a less-than perfect landing. They have no reports of in-flight failures. They did agree that it may be somewhat of a manufacturing defect with too brittle of a compound that the gears are molded from. Here is a picture of the plane: I am going to keep one 635 on the rudder, as it has a pull-pull setup, and the tailwheel runs off a separate servo- I see no potential for shock load here.
Attached Thumbnails Click image for larger version

Name:	Lj23276.jpg
Views:	34
Size:	84.6 KB
ID:	329669  
Old 10-19-2005, 02:36 PM
  #12  
JEREMYB
Member
My Feedback: (1)
 
Join Date: Apr 2004
Location: HASKINS, OH
Posts: 36
Likes: 0
Received 0 Likes on 0 Posts
Default RE: Hitec 635 HB use not as originally advertised

I just bought some of the 635 servos. I hope they work better for you and hold up good for me.. I like that plane that you showed a photo of. What is it? Is it a kit or arf?

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off


Thread Tools
Search this Thread

Contact Us - Manage Preferences - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service -

Copyright © 2024 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.