Spectra-g: What servos are you guys using?

[rbort]

Well I've had my Spectra-g flying for about 8 months now. When it was new I installed 3 new JR 8311 servos in it. To date I have 93 flights on it.

Here is some history:

I put in the G26 Hanson 3D motor and on flight #12 the link popped off and I crashed it from a hover. I pulled that motor out and replaced with a G231 and people said the G26 was too vibrant for the model.

Flew the G231 for 70 flights until #82 with no issues. Sent my G26 to Al and it came back with a lighter piston. I put it in before going to the MHA ff and did a couple of flights, all good.

At the MHA ff I noticed that the delrin ball was causing my engine to wobble a bit (read other post I did about this). Tim and I fixed this and that was a great find and good to fix.

Anyway, that day one of my servos stopped working and I ended up crash landing it. Tore the boom off (boom strike) but the body was intact so the damage was not too bad. I replaced that servo and flew again.

Yesterday another servo (one right below it) went bad. This time I was able to save it and land in 1 piece. Servo was not responding in the middle of the stick but if I went to the extremes it was following OK. When I got home and turned it back on to retest it looked all fine like it cooled off or something. Couldn't get it to fail. I replaced it as well.

So two servos failed within 93 flights. One actually at around 85 flight and the other on 93. This is too quick for me. I'm wondering if the G26 shaker (the first 12 flights) didn't help matters much and/or if the delrin ball issue caused this as well. The third servo is suspect to go soon now too...

So wanted to ask what servos you guys are using and if they have lasted over 100 flights for you with no issues. I'm thinking the JR 8311's are not the best maybe and maybe I should try a different brand or model? Want some input from you guys if possible to help me decide.

Lastly I am dating my servos now with flight # and date they go in. Once I get the two bad ones back from JR repaired or replaced, I will put them in with dates and give them one more chance (now that everything is fixed - engine and delrin) before I decide to jump models or brands.

Thanks guys!

-=>Raja.

[bigrcr]

I use 8311's. The only failures that I have had with the servos turned out to be that the servo leads would be worked against the servo case when I had the wires bundled tightly. The wires were working back and forth where they entered the case and over time the servo would quit as a wire would break. I am one lucky SOB as I never had a crash from the wire failures.
I started potting the wires with Goop as they exit the servo case and re-routing the wires so as not to strain them and have no more issues.


The other failure was due to slamming the machine around while testing the Toxic tuned pipe system in very FFF as the gears stripped.
H to the C noticed the servo problems while the machine cooled after the flight! :oops:

History:

-Throttle servo failure @ flight 187 using G-231.

-Servo gears sets blow in collective and elevator servos (from hammering collective in FFF) @ flight 403.

-Throttle servo failure @ flight 467 using G-26.

Later,

[Toadster25]

Man I don't want to hear that! I have 8311 in mine and prety much have the same story as you Rbort. Started with the G26 and now have G231 I have been worried about the servos ever since I first started flying my Spectra G with the G26 because they were shaking like crazy durring the break in with my G26. I don't keep track of my flights but I have had 2 throttle servos go bad so far. JR811 just quit moving and then using a cheap JR standard servo the gears stripped out but I am using the return spring on the carb. Replacing all three 8311 for prevenative maintanance is kind of expensive.

[rbort]

Man I don't want to hear that! I have 8311 in mine and prety much have the same story as you Rbort. Started with the G26 and now have G231 I have been worried about the servos ever since I first started flying my Spectra G with the G26 because they were shaking like crazy durring the break in with my G26. I don't keep track of my flights but I have had 2 throttle servos go bad so far. JR811 just quit moving and then using a cheap JR standard servo the gears stripped out but I am using the return spring on the carb. Replacing all three 8311 for prevenative maintanance is kind of expensive.

Toadster:

Don't value the failure of the 811 servo. Its a cheap junk servo and it fails rather quickly with any sort of vibrations. It is best suited for your airplane and not heli. I had mine fail like yours in my older 1005 gasser and since JR replaced it with another now I use it as a throttle servo in my airplane. A better life there for it there....

BIGRCR:

407 flights that's pretty impressive! I've just finished my 97th flight. They seem to take a while as each is 15 minutes long so I'm getting close to 25 hours in the air. So are you saying you have an 8311 servo in that machine that has lived all 407 flights in there? Or, if not what is the longest an 8311 servo survived in your Spectra-g?

On my 1005 the longest for mine was about 440 flights. Average is around 350 flights I think on the 8311's there. But in my Spectra as you can see above I didn't get past 100 flights and two servos have crapped out already. I still think it had to do with my unbalanced G26 (well it was balanced, a Hanson 3D, but it wasn't an Al reworked Hanson 3D plus as they say), and my delrin ball being offcenter.

I put 4 flights in today from 93 to 97, all is sweet and running good. The only issue I had is the wire to the voltwatch broke off. Kinda exactly what you said about the servo wires. I should check mine to be sure they are OK before I send the servo for service. I was thinking today after I fix it or get another voltwatch I should goop the wire to prevent it from flexing back and forth in flight until it snaps. The bummer is now I cannot see my generator charging in flight so I'm back to checking the battery with an ESV meter after every flight to make sure all is still good. I'll fix it as soon as I get back home -- I'm in Maine now for the 4th on holiday.

-=>Raja.

[Toadster25]

Well I just had my Futaba S9256 servo quit. This is the servo that comes with the 611 gyro. I've only used this gyro in my Spectra G and it isn't even a year old. It has been through 2 crashes but only had to replace the gears one of the times. I also had to replace the top of the servo case since the mounting ears broke off. I don't know if that had anything to do with it but I think the main problem is the normal Zenoah engine vibration. It quits moving but then if I tap on it, it will start to work again and then quit again, like it is unplugged.

[ClayK]

I have 9255's all around, because my level of flying demands the high torque and quick response time that the 9255's kick out :glasses2:

Yes, that includes throttle :lol:

[rbort]

Toadster:

That's what happens when my 8311 servos quit, they just stop moving and then you wiggle the horn and all is good again but not really. The last one that died stopped moving in the center portion of travel, but if I went to the ends it responded. Actually that's how I got it down in 1 piece I guess. But when I got home and it had a chance to cool off, it wouldn't repeat the problem. Took it out, put in another and dated it this time including flight count, and will see how long it will go now that the machine is smooth with the g26 pro plus and my delrin ball fix.

We didn't hear back from BIGRCR....guess we won't know for sure how long his servos lasted unless he responds. I'm thinking NOT 407 flights...

Clay:

Have you been flying the Spectra lately? All setup and ready to go or what? How's that on-board generator doing? Mine did well this long 4th weekend, I put in 14 flights ( a whole gallon ) and today I ran out of gas and TX battery all at the same time, RX battery is showing 5.1 on the ESV after landing! :D

-=>Raja.

[ClayK]

8th flight and I have a high pitched whine from near the clutch bell while at idle. Bad tail vibration, but I think that might just be engine tuning/mixture. She's currently being taken apart and checked, that is to say, she's sitting on my workbench waiting for the work to be done.

Head is getting swapped out as well while she is in a maintenance cycle.

[paulw1283]

So pretty much if we own a spectra we will be expected to replace servos every couple of month or else crash is inevitable?

That's pretty expensive in the long run....

[DebianDog]

or else crash is inevitable?

That's pretty expensive in the long run....

If Clay is flying... yes it is expensive. Everyone else should be fine. I have 9202 in mine and they work well. Clay's Spectra is puny, comparatively, to the Condor.

[ClayK]

I try my best to keep the US economy afloat with my hobby expenditures :)

[paulw1283]

or else crash is inevitable?

That's pretty expensive in the long run....

If Clay is flying... yes it is expensive. Everyone else should be fine. I have 9202 in mine and they work well. Clay's Spectra is puny, comparatively, to the Condor.

How long have you used the 9202s?

How often are we supposed to replace the servos?

[Toadster25]

That is what I am thinking too. This is going to be very expensive. I may try to find a cheap servo to use insted of these $100 ones except I think that you have to use the 9256 with the 611 gyro.

I was planning to use this heli for taking pictures with but if I can't trust the servos to last then I don't know if I will want to fly with camera gear on it.

[DebianDog]

Since October. 4+ gallons which is a LOT of flights (hours and hours) on a gasser. I have never replaced servos. A 401 has served me well also.

[rbort]

It depends on many factors...servos you use, where they live, how you fly, etc etc.

In my 1005 gasser the longest run on a servo I had before it dies was around 440 flights. Average though is about 300 flights and then its time to replace them. This is with the 8311 high priced servo. Futaba 9202 servos lasted less than 200 flights for me.

In the Spectra I don't have enough experience yet to state some good facts, but I can say that I had a problem with my engine alignment for the first 84 flights due to a bad delrin ball and that probably didn't help matters much. Now its fixed so I want to replace the servos and date them so I'll know from here on out. I sent the bad ones to JR for service today, have to wait until I get them back.

Lastly, I wanted to add that I have been flying the Spectra quite hard - harder than the 1005 gasser and I have been pulsing the servos doing some "step" rolls and "step" loops and such -- that is when you wiggle the stick quickly from center to the side back and forth to cause this effect. When I fly like this I feel like I'm trying to break the model -- its fun -- but its probably not the best for the machine and the electronics!

So that all being said, if you are doing some AP work I would expect the servo life to be longer, since all you do mostly is take off and hover then come back. Pretty much no aerobatics and the servos spent most of their time centered and not jumping to extremes under 3D loads.

-=>Raja.

[paulw1283]

are those servo longetivity similar for all 3D 90 sized machines or are they just particular to the spectra?

in another word, is servo replacement normal for all helicopters or is it just the spectra g that is hard on servos?

[Toadster25]

I don't keep track of my number of flights but I would guess I have around 10 gallons of fuel through my Spectra. I think that the Spectra G is a little harder on servos than a nitro heli because the Zenoah gas engine has more vibration than the nitros. The older Xcell gasser had a plastic radio tray that probably doesn't transfer as much engine vibration to the servos. Except the elevator servo is mounted high in the rear of the frame but they mounted it with some extra rubber gromets that help isolate the vibration. My Xcell 30 with the carbon frames had the same setup but I guess they think the servos can handle the vibration better than they used to because they are all mounted directly to the carbon frames? It does make the heli look better and not as clutterd up by mounting the servos directly to the frames.

[bigrcr]

We didn't hear back from BIGRCR....guess we won't know for sure how long his servos lasted unless he responds. I'm thinking NOT 407 flights...


Yes Rbort, the servos for cyclic/collective are the same as the ones originally installed in the shop at Miniature. These servos have had gear replacements, but none have failed. Of course now I am wondering if I need to go ahead and replace them out of respect. :oops:

BTW- I went back and checked. I have replaced the servo gear in the servos more than once, some of these were due to crashes and some due to gear damage while flying.

The failures that I have had (servos quitting) have all been on throttle and all of those were issues with the servo lead breaking at the case.

Later,

[paulw1283]

Okay, so what should I do? I got 9202 servos and a Gy601 (with the servo that came with it) for my spectra. I'm still in the building process.

Upon hearing this thing about servo failures on the spectra, I'm a little worried. I would hate to have a crash due to servo failures.

Should I just replace all the servos every year? But that seems so uneconomical, as the main reason I like gassers is because they save money on fuel.

[DebianDog]

Well John Garst flys his helicopters pretty hard if you have never seen him fly. Unless you are at that level of flying I seriously doubt you will have to replace gears every year. The same is true for nitro ships. This is not a "gasser only" thing.

[rbort]

Well that's good news then. As I was saying before I've already replaced one 8311 in mine and dated it, I also put in a new throttle servo (8417) and dated that one. I need to replace the other two collective servos and hopefully when they come back from JR (the two I sent out), they will be repaired or replaced and I can put them in and start with a clean slate.

Then all servos will be new except for the rudder 611 servo and we will see how it goes from there. I hope to be able to log 400 flights like you with no issues, that would be great!

-=>Raja.

[bigrcr]

I personally feel that the throttle servo is being pup into movement as it sits on the carbon plate and is supported under the frame set. I am NOT saying that the servo has improper support, but a harmonic can make the servo wire to case joint work back and forth, this I know happens.

I started "potting" the wire as it meets the case with "goop" and have stopped this from occurring (so far it has not occurred in a long time) as the wire can no longer flex back and forth at the case joint.

Later,

[paulw1283]

Perhaps I should number my flights too. And change my servos every 300 flights or so? Is that necessary?

I'm just an intermediate pilot.

[bigrcr]

I keep up with my flight and the events that occurred during the flights for other reasons. Keeping up with the number of flights won't help any IMO as the failures have been conditional. The servos in my case have all been because of conditions (hammering the flight controls-gear failures/servo wires fatiguing-due to flexure) and were not mysterious events that would occur over time.

Any root cause will have a CONDITION and an ACTION that worked upon it.

Later,

[rbort]

If anything numbering flights and keeping track of things give you an idea of when things wear out. Personally I believe that after 300 flights on a servo in your gasser, you are on borrowed time and eventually that servo is going to fail question is just... when?

Sure you can pump the collective and damage something like John says, but I bet you that it wasn't the first time he did that and it worked several times before finally breaking after wearing out to do so. I see people fly stuff really hard, pump collective, jump back and forth, do "rainbows" right close to the ground and bounce the other way, etc. I talked to one of those guys and he said he dates servos and replaces them once a year regardless and then just sells the ones that come out on-line. Its preventative maintenance.

The choice is yours. Fly it till it breaks and risk a crash or get lucky and land, or replace it after a certain # of flights, whatever you deem that to be, to prevent such an event. Nothing lasts forever in my opinion, the trick is to know when to stop using it before it breaks!

-=>Raja.