9151 Servo Failure
08-07-2003 | 03:46 AM
#1
Thread Starter
My Feedback: (38)
9151 Servo Failure
Bax:
A couple months ago, I questioned you as to the strenght of the plastic gears in the 9151 servo as I was going to use them in a 1/4 and a 1/3rd scale plane. You responded by saying there is pros and cons to both metal & plastic gears. I was looking for more of an answer like they would be plenty strong enough. In looking through the available digital servos that Futaba makes, it was the only one that had 130oz of torque. I was looking for something to compare with my 9206 servos which I have had extremely good luck with and have them in several planes. I just wanted to try my luck at digitals. Anyway, today I attempted my first flight on a Dave Patrick Edge with a DA-50. This plane is comparable to Great Planes Patty Wagstaff Extra in size and weight. I had 9151's all the way around. 1 on each airleron, 1 on each elevator half and one on the rudder. On the 3rd pass at 1/2 throttle, the airlerons began to flutter. Both airleron servos were completely stripped and the airplane was lost. Upon inspection, the robart hinges were not damaged nor the airlerons themselves. All servo plates and all linkages were intack and working. I used metal servo arms with ball links, composite tubes with titanium ends, and sullivan metal horns. It was a very stable slop free system that has served me well in the past. This leads me to believe that the servo's themselves were not strong enough for this 15lb airplane. What is you opinion? I have 11 of these servo's at over $100 each and am afraid to use them. I have 6 still in the package ready for a 1/3 scale Fiberclassics Extra with a DA-100 and there is no way I can afford to even think about using them. Can they be converted to metal gears. If not, can they be exchanged for 9206's. What do you recommend to resolve my problem. Oh, by the way, I fly them with a 9Z WC2 radio. I like to buy the best eqipement available and don't mind spending the money. But when I do spend the extra money, I do not expect these kinds of failures.
Sincerely Yours,
Paul Eagon
A couple months ago, I questioned you as to the strenght of the plastic gears in the 9151 servo as I was going to use them in a 1/4 and a 1/3rd scale plane. You responded by saying there is pros and cons to both metal & plastic gears. I was looking for more of an answer like they would be plenty strong enough. In looking through the available digital servos that Futaba makes, it was the only one that had 130oz of torque. I was looking for something to compare with my 9206 servos which I have had extremely good luck with and have them in several planes. I just wanted to try my luck at digitals. Anyway, today I attempted my first flight on a Dave Patrick Edge with a DA-50. This plane is comparable to Great Planes Patty Wagstaff Extra in size and weight. I had 9151's all the way around. 1 on each airleron, 1 on each elevator half and one on the rudder. On the 3rd pass at 1/2 throttle, the airlerons began to flutter. Both airleron servos were completely stripped and the airplane was lost. Upon inspection, the robart hinges were not damaged nor the airlerons themselves. All servo plates and all linkages were intack and working. I used metal servo arms with ball links, composite tubes with titanium ends, and sullivan metal horns. It was a very stable slop free system that has served me well in the past. This leads me to believe that the servo's themselves were not strong enough for this 15lb airplane. What is you opinion? I have 11 of these servo's at over $100 each and am afraid to use them. I have 6 still in the package ready for a 1/3 scale Fiberclassics Extra with a DA-100 and there is no way I can afford to even think about using them. Can they be converted to metal gears. If not, can they be exchanged for 9206's. What do you recommend to resolve my problem. Oh, by the way, I fly them with a 9Z WC2 radio. I like to buy the best eqipement available and don't mind spending the money. But when I do spend the extra money, I do not expect these kinds of failures.
Sincerely Yours,
Paul Eagon
08-08-2003 | 01:32 PM
#2
Thread Starter
My Feedback: (38)
9151 Servo Failure
Bax:
upon inspecting the servos, the first and second gear are stripped. The reason I chose these servos is because Chip Hyde used them on his 40% Ultimate. At least that is what the equipement list in the RCM article about the TOC said. Now I find it hard to beleive cause they won't hold up to my 15lb airframe. I have had serveral responses to my inquiry on RCU and found out that these servos are basically made for pattern airlplanes in the 11lb range and not for a 3D scale gasser? Why isn't information like this listed in your brochures so that a person can make an informed decision. I tried asking you if they would be OK for my application prior to purchasing them but only received a standard non-informative answer. My question is, may I return all 11 servo's to you. This would include 5 still in the original packaging and 6 used for one flight. The 6 used one have had 20 guage extension soldered on. I am in a fix. I have spent a ton of money ($2,000) on Futaba servo's and receivers in the last 3 months and now can't use any of it due to being afraid to use any of the servos for a 1/4 and 1/3rd scale gas planes. I don't see any digital servos with metal gears that are in the 120 to 130oz range (standard case size) that would work. I would probably like to stay with the 9206 servo as I have them on several 1/4 scale planes and they have served me well. Why don't you make a servo comparable to JR's 8411?
Paul Eagon
upon inspecting the servos, the first and second gear are stripped. The reason I chose these servos is because Chip Hyde used them on his 40% Ultimate. At least that is what the equipement list in the RCM article about the TOC said. Now I find it hard to beleive cause they won't hold up to my 15lb airframe. I have had serveral responses to my inquiry on RCU and found out that these servos are basically made for pattern airlplanes in the 11lb range and not for a 3D scale gasser? Why isn't information like this listed in your brochures so that a person can make an informed decision. I tried asking you if they would be OK for my application prior to purchasing them but only received a standard non-informative answer. My question is, may I return all 11 servo's to you. This would include 5 still in the original packaging and 6 used for one flight. The 6 used one have had 20 guage extension soldered on. I am in a fix. I have spent a ton of money ($2,000) on Futaba servo's and receivers in the last 3 months and now can't use any of it due to being afraid to use any of the servos for a 1/4 and 1/3rd scale gas planes. I don't see any digital servos with metal gears that are in the 120 to 130oz range (standard case size) that would work. I would probably like to stay with the 9206 servo as I have them on several 1/4 scale planes and they have served me well. Why don't you make a servo comparable to JR's 8411?
Paul Eagon
08-08-2003 | 07:25 PM
#3
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From: Tupelo,
MS
9151 Servo Failure
Paul:
Sorry to hear about your prediciment and losing your edge. I had a S9151 strip too on rudder (AW 29% Edge) - I replaced it with a S9350 digital (139oz/.12s) that's exactly the same size and metal geared, and it is working out great. A S9451 digital is the same size too and rated at 120oz/.10s, also w/metal gears. Hope this helps. Maybe you could ask the place you purchased them if you could return the unopened ones or maybe exchange them for 9350/9451's.
Good luck!
Sorry to hear about your prediciment and losing your edge. I had a S9151 strip too on rudder (AW 29% Edge) - I replaced it with a S9350 digital (139oz/.12s) that's exactly the same size and metal geared, and it is working out great. A S9451 digital is the same size too and rated at 120oz/.10s, also w/metal gears. Hope this helps. Maybe you could ask the place you purchased them if you could return the unopened ones or maybe exchange them for 9350/9451's.
Good luck!
08-09-2003 | 02:17 PM
#4
Thread Starter
My Feedback: (38)
9151 Servo Failure
Matlock:
Thanks for your reply, I wish I could hear from Bax.
I ran right out and got my new Futaba brochure to look at your suggestions for servo's.
The 9350 is described as a "Hi-Torque Steering Car" and is rated for 6 volt only at 138.8oz/.12sec. That is why I did not choose it. Is that a misprint on 6V only? It is also not recommended on their chart for airplanes.
This new brochure that a friend picked up at Toledo this year does not even list a 9451? They list a 9450 metal geared at 111oz/.10sec. It is described as "Hi-Speed Car" but checked OK for airplane use. Maybe this should have been the choice. I did not choose it because it is actually rated lower at 6V use. 88.8oz/13sec. I thought this may have been a misprint and reversed making it 88.8 at 4.8V and I wanted at least a 100oz servo at 4.8 volt.
What is your opinion.
Thanks for your reply, I wish I could hear from Bax.
I ran right out and got my new Futaba brochure to look at your suggestions for servo's.
The 9350 is described as a "Hi-Torque Steering Car" and is rated for 6 volt only at 138.8oz/.12sec. That is why I did not choose it. Is that a misprint on 6V only? It is also not recommended on their chart for airplanes.
This new brochure that a friend picked up at Toledo this year does not even list a 9451? They list a 9450 metal geared at 111oz/.10sec. It is described as "Hi-Speed Car" but checked OK for airplane use. Maybe this should have been the choice. I did not choose it because it is actually rated lower at 6V use. 88.8oz/13sec. I thought this may have been a misprint and reversed making it 88.8 at 4.8V and I wanted at least a 100oz servo at 4.8 volt.
What is your opinion.
08-10-2003 | 07:28 AM
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From: Tupelo,
MS
9151 Servo Failure
Looking at the digital servo listings at http://www.futabarc.com/servos/futm0211.html , they don't explicitly show a servo over 100oz @4.8v except for the 9151, but I'm not sure why a servo rated at 6v couldn't be used at 4.8 also? It's kinda confusing, b/c if you look at the 9350 and (new?) 9351, one says "N/A" and the other "N/R" for 4.8v usage - I don't dare to interperet the difference between the two meanings. Hopefully Bax or Krysta will chime in soon and clear all this up. That new 9351 is listed for 180/.15 at 6v, so if it could be used at 4.8v I'd imagine it'd still be over 100oz. But of course that's no good if it turns out to be nylon-geared like the 9151's!
Just out of curiosity, do you have anything against 6v or do you just not want to have to buy extra batteries/regulators?
Just out of curiosity, do you have anything against 6v or do you just not want to have to buy extra batteries/regulators?
08-11-2003 | 03:42 PM
#7
My Feedback: (11)
9151 Servo Failure
Sorry to get back so late. We're sorry to hear about the difficulty with your model. In all liklihood, the servos were damaged from the flutter. On all models, but especially aerobatic types, flutter is a distinct possibility. Especially on those aircraft with very large control surfaces. The flutter would have damaged the servos as you described. Even the strongest servos would be hard-pressed to withstand the beating a fluttering surface can give.
130-ounce-inches of torque is plenty strong for a wide variety of models. It's the fact that you experienced the flutter, which caused the damage. You can have excellent servo mountings, a good servo arm, slop-free linkages, excellent hinges and hinge line, and still experience flutter.
With a fluttering surface, it would matter little whether the servo had metal or plastic gears. The flutter could destroy either.
130-ounce-inches of torque is plenty strong for a wide variety of models. It's the fact that you experienced the flutter, which caused the damage. You can have excellent servo mountings, a good servo arm, slop-free linkages, excellent hinges and hinge line, and still experience flutter.
With a fluttering surface, it would matter little whether the servo had metal or plastic gears. The flutter could destroy either.
08-12-2003 | 12:59 PM
#8
Thread Starter
My Feedback: (38)
9151 Servo Failure
Bax:
I realize that you have to be very careful when responding to questions like mine that are a result of a crashed aircraft.
However, if a consumer cannot ask a manufacturer which of their products would best suit the consumers specific use, then the consumer would be better off finding a manufacurer that will.
How else can you make an informed purchase?
I am trying to stay loyal to Futaba products but your answer was close to a slap in the face. Anyone who has flown airplanes for any length of time knows that any airleron has the potential to flutter. It is inherrent in them. Therefor the builder, paticularly of a high perfomance airplane, needs to take great care in the construction and equipement used to construct the aircraft.
In my case, I used all first rate equipement for hinges, linkages. control arms, etc, and sealed the gaps. Your next choice is to use the strongest servo you can afford as this is the last link in the failure chain.
In my case, I should have used a metal geared servo as the plastic gears were not sufficient to hold and keep the airleron from fluttering.
I will solve this problem by using 2 - 9151's on each airleron once the plane is rebuild. Not because I think they are the best servo for the job but because I am now stuck with these servo's after making an under informed purchase due to the manufacturer refusing to respond to a direct request as to their intended use.
Your refusal to respond to several direct reasonable questions that I and several others asked in this thread about your products does not speak well of Futabas customer support. Companies such as yours live and die due to customer support.
Pleae re-read the questions put forth in this thread. They are legitimate consumer questions that deserve an answer.
Sincerely Yours,
Paul Eagon
I realize that you have to be very careful when responding to questions like mine that are a result of a crashed aircraft.
However, if a consumer cannot ask a manufacturer which of their products would best suit the consumers specific use, then the consumer would be better off finding a manufacurer that will.
How else can you make an informed purchase?
I am trying to stay loyal to Futaba products but your answer was close to a slap in the face. Anyone who has flown airplanes for any length of time knows that any airleron has the potential to flutter. It is inherrent in them. Therefor the builder, paticularly of a high perfomance airplane, needs to take great care in the construction and equipement used to construct the aircraft.
In my case, I used all first rate equipement for hinges, linkages. control arms, etc, and sealed the gaps. Your next choice is to use the strongest servo you can afford as this is the last link in the failure chain.
In my case, I should have used a metal geared servo as the plastic gears were not sufficient to hold and keep the airleron from fluttering.
I will solve this problem by using 2 - 9151's on each airleron once the plane is rebuild. Not because I think they are the best servo for the job but because I am now stuck with these servo's after making an under informed purchase due to the manufacturer refusing to respond to a direct request as to their intended use.
Your refusal to respond to several direct reasonable questions that I and several others asked in this thread about your products does not speak well of Futabas customer support. Companies such as yours live and die due to customer support.
Pleae re-read the questions put forth in this thread. They are legitimate consumer questions that deserve an answer.
Sincerely Yours,
Paul Eagon
