mikeh251

I'm not real comfortable with the performance of these servos. I am using one as a throttle servo at 6volts and it just does not sound or act like it likes the extra voltage. I have others in Sig ep20's which are a 2-1/2 lb. fourstars. These are 4.8 volts. I don't experience the same problem with these. But I am concerned about how much noise and complaining these things do even at 4.8 volts. All of my surfaces move freely beyond the amount of travel I have set up. I am afraid to run hi rates on these just because I don't trust these servos just because of the way they behave. I have had some of my standard Futaba servos make a little noise here and there, but nothing that worries me. Has anyone else used these and are they safe? Are the 3117 Futabas better?

Gray Beard

My Feedback: (-1)

Been using the HS 81s sense time began without problems at both 4.8 and 6 volt for a number of controls. They do react very fast compared to other servos at the same voltage but other then that I haven't seen anything odd. The motors are very small so I tell most people to use them for nothing in a standard glow or gas type plane besides throttle. I have used them on the ailerons of small over powered race planes in the ailerons without problems a couple of times but it's not something I do on a regular basis.
The gear train is nylon too, just something to give thought to. Today we have servos in the same size with metal gears, I will be using them in a scratch build I'm doing right now for the small ailerons. I'm not sure about the trust issue but I use them and have used them for years without a failure. That could just be a lot of luck on my part?

Crash-RCU

I have a Nitroplanes Bobcat 52 that I modified by putting a HS-81 servo in the middle of the horizontal stab for the elevator, works just fine. I run 6 volt in everything and have not had any problems with it

Boomerang1

I use them on fuel valves on jets. I noticed a couple got the jitters when I first turn the radio on with no
load on them at all. They settle down after a few secs. I have another on a throttle & a pair on rudders
on a Bobcat 50 with nothing unusual happening. I'm using them on 4.8V - John.

WaffleMan

My Feedback: (1)

I use them on my electric powered "mini magic extra" for all of the control surfaces. I put that plane through a heck of a lot of stress and none of the servos have ever failed on me. I run them at 6 volts.

mikeh251

I have also had many successful flights with the fourstars at 4.8 volts (up in the sky where I can't hear them complain). Hope this continues!!! I am afraid of using the one I have in my Somethin Extra at 6 volts though. Its just so wierd at 6 volts. Maybe I can slow down the movement of throttle channel on Futaba 6ex and it will settle down? Like some expo maybe? I read alot where folks recommend various Hitec servos, so far I am not sold on them. I have 11 of these and they are the only non standard servos I have. These 81 are the only hitec servos I have. I have 4 3010, 10 s148, 20 3004 standard size Futaba servos. I trust them all, but some make noises if they are overloaded. I would like to try Futaba mini servos but they are of different size than the hitecs I have. But maybe all mini servos are finicky andand I don't know I just don't feel good about them. Anyone tried mini Futabas out there? Cause I already tested the hitecs. they do fly my planes but I dont think I like them. Or maybe I just don't know mini servos, thats the purpose of my post, I guess. Maybe the 6volt problem has me unnecessarily worried about the other servos but I would like some comparison experiences from others so I can make some decisions about what to do.

Gray Beard

My Feedback: (-1)

Keep in mind what the HS 81s were designed for, small 1/2A planes and electrics. They have small motors and pots in them and may not take well to vibration from glow and gas engines. I use them as I mentioned but they should be used with a lot of thought. It takes a bit of study to understand why you use different servos in different places and on different planes. I have one plane at the moment with a pair of HS 81s, A 60 size old school pattern plane, one 81 is on throttle and one is used to steer the front wheel. I use copper wire on the steering wheel so it flexes and doesn't strip the gears on a rough landing, I have had to replace it once when I hit the front wheel too hard, tore out the complete gear train. I would have used a different servo for steering but I have no room. Selection is up to you. I haven't seen a nickles worth of difference between the Hitec, Futaba or JR servos, I use them all but buy when I find a sale.

mikeh251

I think I will just buy one mini servo of another kind to replace the 6 volt throttle servo. i can then do some comparisons.The kits that I built (Sig Ep20) did show photos in the manual of them using the 81's that I have been using. I know many swear by the more expensive models of Hitec mini servos. I did go out and buy more of the 81 model after using them once. I only got real concerned after the 6volt issue.The model I selected was the bargain!!! May need to upgrade in future to a little more expensive mini servo. I know the 3010 Futaba seems better than the 3004 Futaba. Probably the same with the hitec. Sometimes you get what you pay for!

JohnBuckner

My Feedback: (1)

I have been using the HS-80, 81 and 85 for quite a few years on many different aircraft. I use them almost on all most all my throttles and all my multi engine airplanes up to six engines.

I do use them on appropriate airplanes such as the one you have and for example the one in the picture it is a five pound vintage type of airplane with a saito 45 originally and now an OS 35AX. They are used on all the surfaces. But this is not a 3d airplane with humongous throws. The ailerons are just early strip ailerons for example.

Where the eightys will tend to fail easily is during crashs or firm arrivals as do all miniture servos with tiny plastic gears.

The six volt thing is not an issue and virtually all my aircraft out of a fleet something over fifty use 6 volt systems.

One issue you must pay attention to with the eighty series is the fact that they all are two bolt mounts Not Four. What this means is you cannot mount them side ways and always must he mounted longtitudinaly in the airplane.

Sorry can,t post the picture this early AM must be RCU,s flaky server this morning

If mounting sideways as many do especially for throttles will cause rocking no matter how tight the screws and this will cause throttle end point problems. If on elevators for example it will cause a strange pitch hunt. Thats a no/no for any two bolt servo, no sideways mounting.


John

SeamusG

Off topic: John B - do you have a schedule where you keep your entire inventory actively flying?

Gray Beard

My Feedback: (-1)

Thanks for the info John, I was going to side mount a couple of the small servos for the ailerons in my Swoose builds. I don't recall ever side mounting them in a plane but I didn't know I wasn't supposed to do it. Other then the 81 I use for the steering wheel on my Daddy Rabbit that is the only servo I have ever stripped a gear in. Landing hard on the nose wheel like I did would strip out brass gears too in any servo I would have used. A real bad landing!

mikeh251

I have the servos all mounted longitudinally. it's hard to describe the problem in words that I am seeing with the 6 volt throttle servo. Its very noisy and does not seem to consistently move at the same speed. It does seem to stop at the right spots all of the time, but its like, I don't know, watching it and listening to it I am expecting it to start smoking or burst into flames at any moment. Its like it wants to go really super fast or something and then it just seems slow and all the while it rattle and buzzes. I have tried others and they all act crazy unmounted. I thought securing it to the tray would settle them down and mouted one, but it is crazy when installed also.

mikeh251

Wait a minute, I am NOT sure about the mounting of the throttle servo now that I think about it. I will check it out and charge everything and report how it is mounted and more about how it is working. May take a day or two.

JohnBuckner

My Feedback: (1)

Oh man thats one of my all time favoites never got around to building one. This is my buddys down at Havasu and we,ve had a number of mock races with my Schneider Sport. Certainly a beautiful airplane.


John

Gray Beard

My Feedback: (-1)

Thanks John, I filed that photo away. Getting any info on the Swoose is very hard, everyones favorite but almost never built? Hope you have more photos on file!

JohnBuckner

My Feedback: (1)

GB got some more pics for you but the PM system will not accept them even though they are not oversize.

So can you PM or post your Email address for me[8D]

John

mikeh251

I took my airplane down from the rafters and see that I do have the servo mounted in the direction where it can rock back and forth. I set up the epa so that there is no binding, getting good full motion to fully open and close throtttle to idle (at zero trim). Kill button fully closes barrel and servo is not strained during any of these extremes of wot and kill button. the linkage is very smooth and straight and doesn't require much force to operate. The servo does not rock or move at all (even though I am not crazy about the sideways placement of the 2 bolt unit). Now, I notice that the servo is working very well with no bad behaviors noticed. The only thing is, the battery is no where near fully charged. I have a 5 cell nimh pack. I will be back to report if the servo behaves strangely with a fresh higher voltage charge, as that is one variable left to look at and report. Thanks for the help.