Servo Question???
03-27-2010 | 03:41 PM
#1
Thread Starter
Senior Member
Servo Question???
Answers please,
I am ready to put servos in my Ziroli P-40 and I am tight on funds. I have 5 Hitec HS-635HB's that I want to use. These are the ones with the Karbonite gears. The spec's on Tower state only for planes up to 12lbs. Mine will be 28 to 30lbs. I had them in my FuntanaX 100 for 1 flight before I quit flying it when I bought my Twist 150 for beating about. On that plane which weighed at least 15 to 20 lbs. they were great and I put it through it's paces and it has huge control surfaces unlike the P-40. So these are really just like new. What do you think of these servos? Please don't tell me what you would use because I just need to know if these will work. Remember I have these and nothing else. I know what to get if these definitely won't work. But I don't want to buy them if these will work.
Barry
I am ready to put servos in my Ziroli P-40 and I am tight on funds. I have 5 Hitec HS-635HB's that I want to use. These are the ones with the Karbonite gears. The spec's on Tower state only for planes up to 12lbs. Mine will be 28 to 30lbs. I had them in my FuntanaX 100 for 1 flight before I quit flying it when I bought my Twist 150 for beating about. On that plane which weighed at least 15 to 20 lbs. they were great and I put it through it's paces and it has huge control surfaces unlike the P-40. So these are really just like new. What do you think of these servos? Please don't tell me what you would use because I just need to know if these will work. Remember I have these and nothing else. I know what to get if these definitely won't work. But I don't want to buy them if these will work.
Barry
03-27-2010 | 04:17 PM
#3
My Feedback: (102)
RE: Servo Question???
Barry,
Read up on those servos. The reason they are rated for a 12 lbs plane is because of all the broken serovs on larger planes. They break right at the control arm. They also say don't use on a gas plane... They should have recalled that servo!! It was a replacement servo for I think a 625?? which I used all the time. I wished they had left well enough alone.....
Ty
Read up on those servos. The reason they are rated for a 12 lbs plane is because of all the broken serovs on larger planes. They break right at the control arm. They also say don't use on a gas plane... They should have recalled that servo!! It was a replacement servo for I think a 625?? which I used all the time. I wished they had left well enough alone.....
Ty
03-27-2010 | 04:34 PM
#4
Thread Starter
Senior Member
RE: Servo Question???
I found a new Hitec 5645MG that I am going to use for the elevators because they run off one servo with a 1/4" wire connecting the two in a U shape. That is a good servo and can handle the two surfaces. I also found a new Futaba S3010 which I'm thinking of using on the rudder. What about the 635's fot the ailerons which are small? Now I need two more for the flaps. But I'm also thinking of putting the 635's in my Twist 150 which is glow and very light. Maybe even under the 12lbs. and using the Futaba S3305's from it for all the rest of the servos on the P-40 including the ailerons. What do you think of that trade off? I fly the Twist all the time but don't want to have it crash because of a bad servo either. If these 635's are so bad why do they still make and sell them?
Barry
www.canopyrailsforwarbirds.com
Barry
www.canopyrailsforwarbirds.com
03-27-2010 | 06:40 PM
#5
My Feedback: (221)
RE: Servo Question???
The 635 is a good servo for smaller airplanes only, and if you doubt why, take one apart and look at those gears. Put it next to a bonified giant scale servo like a JR 8611. You can't believe how much stronger the JR gears are, albeit at a much higher price. However, you can find Hitec metal gear 645s on fee bay for around 27 bucks. Good servos with a strong gear train and a great track record, yet inexpensive. I use them in giant scale a lot, with no issues. IMO, the 635 is not a giant scale servo.
I also use the 5645 and 5945 servos. Very good for a less expensive alternative, up to a point. For a detailed war bird with all the investment in time and money, I save up and use better equipment. Our new P-47 has just one JR 8611 on the rudder, two JR 8411s on the elevators, two 8411s on the ailerons, two 5645s on the flaps, a 645 on the air valve, JR 4131 on the throttle, 4131 on the choke, and another JR 8611 on the tail wheel. Yes, it is expensive to control these large heavy planes, but I feel I have reliable power at all stations even without buying the biggest and the baddest servos out there.
BTW Barry, we will be showing the P-47 at the Toledo show, and have your product listed in the specs on her. A little shout out for ya.
I also use the 5645 and 5945 servos. Very good for a less expensive alternative, up to a point. For a detailed war bird with all the investment in time and money, I save up and use better equipment. Our new P-47 has just one JR 8611 on the rudder, two JR 8411s on the elevators, two 8411s on the ailerons, two 5645s on the flaps, a 645 on the air valve, JR 4131 on the throttle, 4131 on the choke, and another JR 8611 on the tail wheel. Yes, it is expensive to control these large heavy planes, but I feel I have reliable power at all stations even without buying the biggest and the baddest servos out there.
BTW Barry, we will be showing the P-47 at the Toledo show, and have your product listed in the specs on her. A little shout out for ya.
03-27-2010 | 07:52 PM
#6
RE: Servo Question???
No Karbonite geared Hitec servos on gas airplnes due to gear failures caused by high vibration. The Hitec 5645 would be a good all around servo for that plane.
03-27-2010 | 08:55 PM
#7
Senior Member
My Feedback: (12)
Joined: Aug 2002
Posts: 576
Likes: 0
Received 0 Likes
on
0 Posts
From: Gaston,
SC
RE: Servo Question???
Check out the hd servos that tbm sells...I have 2 on my gas stuka, I believe they are the 120's....18 bucks a piece...I have used several without incident....
03-28-2010 | 12:19 AM
#8
Senior Member
Joined: May 2007
Posts: 198
Likes: 0
Received 0 Likes
on
0 Posts
From: Monterey Park, CA
RE: Servo Question???
Ｔｏ ａｎｓｗｅｒ ｙｏｕｒ ｑｕｅｓｔｉｏｎ ｉｆ ｔｈｅ ＨＳ－６３５ ｗｏｕｌｄ ｗｏｒｋ， Ｉ say maybe for a short time. I would not risk a large gas airplane on questionable powered servos. I did use 2 HS-635 servos，one for each elevator on my 25% Katana for several months with no problems. If you are so short on funds I would not fly the P-40 and wait until I have the money to get some decent powered servos. In many of my larger scale planes I have been using some of the older 1/4 scale servos with very good success. I got them for next to nothing. The problem is that they are a bit heavy and slow, but for scale usage they seem to work fine. And in the 30 years of using them, I have had only one go bad.
03-28-2010 | 07:10 AM
#9
RE: Servo Question???
The setup I would recommend would be dual elevator servos, dual flap ( set up for no load when flaps are down), dual aileron, separate rudder and tail wheel servos (this is to take the shock load off your rudder servo), dual batteries, dual switches. all metal geared. This is simply for safety sake and gives the best chance if some thing was to go wrong. The hitec 5645 servo will work well for all your surfaces and cost about $45 each. Skimping on the radio equipment is a bad idea. I would run something like a Hitec 5245 on the throttles, gear and choke. The metal gears are there for vibration as well as being strong. A 6V system would be the way to go as well as 2.4 ghz. Its not like this is a budget build anyway.
03-28-2010 | 08:22 AM
#10
My Feedback: (221)
RE: Servo Question???
Personally, I respectfully submit, although I use metal gear servos for there torque strength, I prefer nylon gear servos with a (5) pole set motor for vibration resistance on the throttle and choke of the gassers. Nylon is superior to metal when strictly looking at vibration resistance ignoring the torque strength issue, as is the case with the throttle, choke, air valve, etc. Check and see how many poles your nylon drive servo has. If it is 5 instead of 3, it makes a great servo for these applications. It will likely outlast the airframe.
03-28-2010 | 09:50 AM
#11
RE: Servo Question???
Nylon will hold up to vibration well if its not Karbonite or similar material. I just don't like the idea of people using $10 servos in these areas. Precise throttle control is very important.
03-28-2010 | 10:17 AM
#12
RE: Servo Question???
ORIGINAL: ram3500-RCU
Nylon is superior to metal when strictly looking at vibration resistance ignoring the torque strength issue, as is the case with the throttle, choke, air valve, etc.
Nylon is superior to metal when strictly looking at vibration resistance ignoring the torque strength issue, as is the case with the throttle, choke, air valve, etc.
Nylon gets soft under stress - that means when you have a high vibration under high stress they tend to brake off easy. Nylon is not in the family of high resistant plastics. Nylon is easy form able, cheap and has a good "all around" capabilities. Again, Nylon is soft and is a good media for small gears - with a medium load.
One word to the vibrations - servos are protected against vibration (rubber mounts with bushings) because of the solder joints on the leads and circurit boards.
If you like to protect the bearings and gears - use heavy duty servo arms. They are nylon and work a shock absorber.
Barry, a dual elevator with this size of bird is a must. Even you have a strong enough servo which can pull both of them. If you lose one of them - no big deal the bird is may sluggish but still under control. The same with the ailerons - you lose one, sluggish but flyable.
The digital servos have a higher resolution and they are more precise
Give me your control surface measurements and I can calculate the minimum servo for each. And I need the movement in degree or inch, plus the estimated top speed.
Example:
Speed 75mph
aileron
12 long 2inch wide 1/2 inch max defection - and so forth.
Takes you 3 minutes to measure and another 2 to post.....
03-28-2010 | 11:40 AM
#13
My Feedback: (221)
RE: Servo Question???
ORIGINAL: G-Pete
Sorry man but that statement is wrong.
Nylon gets soft under stress - that means when you have a high vibration under high stress they tend to brake off easy. Nylon is not in the family of high resistant plastics. Nylon is easy form able, cheap and has a good ''all around'' capabilities. Again, Nylon is soft and is a good media for small gears - with a medium load.
One word to the vibrations - servos are protected against vibration (rubber mounts with bushings) because of the solder joints on the leads and circurit boards.
If you like to protect the bearings and gears - use heavy duty servo arms. They are nylon and work a shock absorber.
Barry, a dual elevator with this size of bird is a must. Even you have a strong enough servo which can pull both of them. If you lose one of them - no big deal the bird is may sluggish but still under control. The same with the ailerons - you lose one, sluggish but flyable.
The digital servos have a higher resolution and they are more precise
Give me your control surface measurements and I can calculate the minimum servo for each. And I need the movement in degree or inch, plus the estimated top speed.
Example:
Speed 75mph
aileron
12 long 2inch wide 1/2 inch max defection - and so forth.
Takes you 3 minutes to measure and another 2 to post.....
ORIGINAL: ram3500-RCU
Nylon is superior to metal when strictly looking at vibration resistance ignoring the torque strength issue, as is the case with the throttle, choke, air valve, etc.
Nylon is superior to metal when strictly looking at vibration resistance ignoring the torque strength issue, as is the case with the throttle, choke, air valve, etc.
Nylon gets soft under stress - that means when you have a high vibration under high stress they tend to brake off easy. Nylon is not in the family of high resistant plastics. Nylon is easy form able, cheap and has a good ''all around'' capabilities. Again, Nylon is soft and is a good media for small gears - with a medium load.
One word to the vibrations - servos are protected against vibration (rubber mounts with bushings) because of the solder joints on the leads and circurit boards.
If you like to protect the bearings and gears - use heavy duty servo arms. They are nylon and work a shock absorber.
Barry, a dual elevator with this size of bird is a must. Even you have a strong enough servo which can pull both of them. If you lose one of them - no big deal the bird is may sluggish but still under control. The same with the ailerons - you lose one, sluggish but flyable.
The digital servos have a higher resolution and they are more precise
Give me your control surface measurements and I can calculate the minimum servo for each. And I need the movement in degree or inch, plus the estimated top speed.
Example:
Speed 75mph
aileron
12 long 2inch wide 1/2 inch max defection - and so forth.
Takes you 3 minutes to measure and another 2 to post.....
Seriously, my statement is based on over 40 years of experimenting and history. My nylon servos last indefinitely and indeed out live the airframes in most cases. Yes, that is why I say for the the throttle etc. And yes, rubber mounted servos are somewhat insulated from vibration. The throttle is not even medium load, it is no load in most cases. Nylon is used as a bearing material in industry and even furniture building, as I have done. Metal wear under the vibration of a gasser is accepted to be as fast if not faster. Miles Reed used nothing but JR servos, even the 8411s, with nylon gears instead of metal, for their tightness, all the way up to and including his famous 40% Weeks. Not to mention that metal on engine servos is a waste of weight. I prefer metal in torque situations on the giant stuff. But for low or no loads, nylon is my choice with 5 poles for durability and tightness.A good, 5 pole, nylon servo will serve you well on your engines, and at a modest cost.
G-Pete is all over the math though, and will help you not waste money by grossly over engineering things.
03-28-2010 | 12:02 PM
#14
Thread Starter
Senior Member
RE: Servo Question???
ORIGINAL: Andrew_S
Check out the hd servos that tbm sells...I have 2 on my gas stuka, I believe they are the 120's....18 bucks a piece...I have used several without incident....
Check out the hd servos that tbm sells...I have 2 on my gas stuka, I believe they are the 120's....18 bucks a piece...I have used several without incident....
Andrew,
Thanks, I looked at the HD servos on TBM and the HD-1501MG is rated at 284oz in at 7.2 V with no regulator needed and they are $18.99 each. I'm going to see what this makes people say. Well guy's what do you think of this servo that has been tested against JR's 8711 servo and came out smelling like roses? Plus remember TBM sell JR also!
Barry
03-28-2010 | 01:01 PM
#16
Senior Member
My Feedback: (12)
Joined: Aug 2002
Posts: 576
Likes: 0
Received 0 Likes
on
0 Posts
From: Gaston,
SC
RE: Servo Question???
You put Sierra gear in the plane, but now you want to run cheap Chinese servos.
Barry, try to get what the manufacture recommends. Myself, I dont run $150 a piece servos..Most of mine are the hitec 5645 digitals. Tehy run about 45 bucks a piece and have 172 oz of torque at 6 volts. I have a 33%sukhoi and have 1 for each elevator and 1 for each aileron. My rudder has a CHEAP CHINESE digital. The only reason I got it was because of the torque rating.. Needless to say, the plane will do knife edge loops on the CHEAP CHINESE digital...Now on the other hand, I bought some different cheap chinese servos, one of them failed on the ground when I was testing the plane out...Maybe just do a search on the different kinds of servos you are thinking of...Hope this helps you some.....
03-28-2010 | 01:20 PM
#17
RE: Servo Question???
If you can afford $800 for landing gear, you should be able to afford some 5645 servos. HD servos may be fine, but it seems like alot of work and money to prove it.
03-28-2010 | 01:24 PM
#18
RE: Servo Question???
ORIGINAL: Andrew_S
Does this mean I should put expensive american servos or cheap chinese servos in my chinese arf with the chinese engine???
You put Sierra gear in the plane, but now you want to run cheap Chinese servos.
....you have 30 pound 50cc missile - aiming (when you lucky) to the ground and not into bystanders. American bystanders...
One more for Ram,
Most throttle arms have a spring, which forces to close the butterfly in the carb in case of an power loss. There is your stress for the throttle servo
03-28-2010 | 03:29 PM
#21
My Feedback: (221)
RE: Servo Question???
ORIGINAL: G-Pete
More like, put some good reliable servos in it. When one of these ''knockoff'' fails and drain your battery in a few minutes....
....you have 30 pound 50cc missile - aiming (when you lucky) to the ground and not into bystanders. American bystanders...
One more for Ram,
Most throttle arms have a spring, which forces to close the butterfly in the carb in case of an power loss. There is your stress for the throttle servo
ORIGINAL: Andrew_S
Does this mean I should put expensive american servos or cheap chinese servos in my chinese arf with the chinese engine???
You put Sierra gear in the plane, but now you want to run cheap Chinese servos.
....you have 30 pound 50cc missile - aiming (when you lucky) to the ground and not into bystanders. American bystanders...
One more for Ram,
Most throttle arms have a spring, which forces to close the butterfly in the carb in case of an power loss. There is your stress for the throttle servo
03-28-2010 | 03:40 PM
#22
My Feedback: (221)
RE: Servo Question???
Look, I understand all about tight budgets. I'm in construction[
], but you saved up for quality gear because you knew it was best for the plane and your enjoyment of it. Why not do the same for an even more important component, the control equipment.
Also, I have pulled scores of good buys off fee bay on top shelf servos. Yes, one or two were not what they were said to be, but the most I have ever done is install a new gear train, and still been far below retail. I have never gotten one with bad electronics. Just a suggestion.
Either way, put as much thought into the radio components as you have everything else, listen to the good advise you are getting here, and make good choices. You will be happy you did.
Too many planes die each year from bad choices in critical components, as good pilots stand by, helpless to save them.[]
], but you saved up for quality gear because you knew it was best for the plane and your enjoyment of it. Why not do the same for an even more important component, the control equipment. Also, I have pulled scores of good buys off fee bay on top shelf servos. Yes, one or two were not what they were said to be, but the most I have ever done is install a new gear train, and still been far below retail. I have never gotten one with bad electronics. Just a suggestion.
Either way, put as much thought into the radio components as you have everything else, listen to the good advise you are getting here, and make good choices. You will be happy you did.
Too many planes die each year from bad choices in critical components, as good pilots stand by, helpless to save them.[
]
03-28-2010 | 06:12 PM
#23
Thread Starter
Senior Member
RE: Servo Question???
Do you guy's really think any of these servos we use are made in the USA? I don't think so!!! I'll take it from here guy's because it's starting to become a joke on here now. It's not a question of what I have already bought it is a question of what I can afford to buy now.
Thanks,
Barry
Thanks,
Barry
03-28-2010 | 07:09 PM
#24
My Feedback: (221)
RE: Servo Question???
Sorry you feel that way. Several guys have taken the time to post based on their experience and made some very good observations along the way, to help you make a good decision here.
Looks like you will be listening to your pocket book instead of these guys, so I wish you well.
As far as where things are made, please don't insult us either. We all know where this stuff comes from. Just remember, knock offs are cheap because they cut corners somewhere to make a look a like, not held to the same standards as the name brand likely is. Better servos have better components and metallurgy, and that is why they cost more. I have had them apart over the years, and it just isn't apples for apples.
As many have pointed out, using cheap knock offs, however they are 'rated', is a crap shoot. OK for a Four Star, but not for your beautiful war bird, IMO. I have actually seen planes go down over the years from servo failure. Have you? Saw one last year. Giant scale 260 using standard servos. Ugly.
BUY GOOD EQUIPMENT, PLEASE.[sm=thumbs_up.gif]
I yield the balance of time back to the floor.
Looks like you will be listening to your pocket book instead of these guys, so I wish you well.
As far as where things are made, please don't insult us either. We all know where this stuff comes from. Just remember, knock offs are cheap because they cut corners somewhere to make a look a like, not held to the same standards as the name brand likely is. Better servos have better components and metallurgy, and that is why they cost more. I have had them apart over the years, and it just isn't apples for apples.
As many have pointed out, using cheap knock offs, however they are 'rated', is a crap shoot. OK for a Four Star, but not for your beautiful war bird, IMO. I have actually seen planes go down over the years from servo failure. Have you? Saw one last year. Giant scale 260 using standard servos. Ugly.
BUY GOOD EQUIPMENT, PLEASE.[sm=thumbs_up.gif]
I yield the balance of time back to the floor.
