Was considering purchasing the GP Reactor Bipe and would like to add in servos to the package to make it more economical when ordering (Wish Tower would offer a promotional discount on the Reactor Bipe other than the one they have emailed me). I am using a 9CAP with TM8 2.4Ghz module and 6008HS RX. I have Futaba S3010s for rudder and elevator but for ailerons I need to decide between s3102 and s9650. The 9650s are digital while the 3102 is analog. So three questions here

1) Can I combine digital and anolog servos on the same airplane?

2) How is everyone's experience with these mini servos?

3) I have 4 Hitec 225MGs in inventory. I had taken these for a Reactor monoplane last year, but one of them failed even before I could finish putting the airplane together and I chickened out and used 3010s all over then. Subsequently, I tested out the remaining 225MGs using the servo test feature on the 9CAP for nearly half an hour and they seem to be working OK. Should I take the risk with these servos on this more expensive airplane?[][&o]

Ameyam

There are no issues with mixing analog and digital servos in a plane.  Just be aware that it is normal for digital servos to "buzz" in the center position. ALso, the digital servos will draw more current than your analog servos which  will drain your battereis faster.

The reactor bipe should use standard servos, stay away from the minis for this plane.

Ken</p>

Actually, I will use standard servos on the rudders & elevator. But I think that minis are required for the ailerons as they go inside the wing. Can anyone confirm this? I will be most happy to use standard servos on the ailerons as well as I have the more reliable 3010s for that

Ameyam

As he said. Standard Servos are fine.

You CAN use "high torque Mini" servos though, but not anything smaller.

Mini servos look slightly smaller than standard size servos, and if you go with higher torque minis you'll be fine.

As RC Ken states, I would AVOID "standard" torque Mini servos though, as this plane has large control surfaces.

Opjose,

have a look at this listing

http://www3.towerhobbies.com/cgi-bin...&I=LXN667&P=ML

the 225MGs are Mini Mighty (67oz-in at 6v, high torque) metal gear servos. I took them with that specific intention- servos suitable for high torque application in the mini size and which will resist stripping (metal gears).

My concern is mainly to do with quality (or the lack of it). It isint very inspiring if the brand new servo fails while you are testing during installation[:@] (on a more positive note, may be thats better than it failing during the flying). So what I am asking is:

1) Is the 225MG suitable for this application?

2) Should I use that servo if it is suitable, specially considering its 4 times more troubling (there are 4 servos on the ailerons remember) and this is a more expensive airplane?

Ameyam

Did you have one fail during testing?


Yes it should be fine.

The cost of the plane doesn't have anything to do with it.

What does is the size of the control surfaces and HOW you set up the linkages.

Make sure you go for MAXIMUM MECHANICAL ADVANTAGE.


I've used one of the 225MG servos to control FOUR ailerons on .40 sized Ultimate biplanes.

The servo drives both lower ailerons which in turn drive the upper.

This has worked just fine for me on three such planes and I'm pretty certain my little 225MG's are overcoming far more force than they would see on the Reactor Bipe.

Just remember NOT to but the control surfaces right up against the wing edge... make sure you leave a small gap so the surfaces can move up and down cleanly w/o binding.

All too often people get so hung up about hinge gaps that they forget to leave ANY gap, which is equally important.

Yes, thats what I wrote above. It failed while we were still centering the aileron. Actually it jammed completely. We opened it up to check whether any gears were in bind but that was not the case, the pot itself had failed and there was not much to do about it. I had bought 6 in all to use in various places on the monoplane and we ended up using none, so I have 5 spare. It will actually cost more than the servo itself if we have to claim returns from Tower, so we didnt do that

Ok, how do you really check whether a given set of servos are reliable? Is the servo test feature on the TX the right way? And if so, how long continuously should I run this feature for testing the servos


Ok I will take care of that

Ameyam

Ameyam, I have done exactly what you are proposing: mixed digital and analog on this exact plane. I'm using the standard sized Tower digital TS126 on the rudder, 2 Hitec 225mg on the elevator, and 4 CS12 analog minis on the ailerons. I have 35 flights on mine already, and love it! Have not noticed any aileron "blow back" on high speed passes or any other issues.

That being said, I've had almost a dozen Hitec 225mg's, used in various planes, and have had at least 4 of them go "bad". They either start jittering/not centering, or quit altogether. I may swap my elevator servos to something else before long. I also was going to use the Tower TS110 digitals on the ailerons of this plane, and 2 of them went bad during installation/setup! Not impressed there either....

Actually doesnt answer my query. I know that the servos are technically good but, practically, how do you check whether a particular set is good or not.

Also, what will happen if one of the servos stops working on a biplane during flight on the ailerons? There are 4 in all, so will the others help compensate?

Ameyam

You "check" them every time you fly the plane!

All kidding aside, the best you'll be able to do is to mount the servo and while exerting a bit of resistance to surface travel, move the servo through it's motion range via the TX.

Look for an unusual "grittiness" or stopping as you do this.

Doing so will not turn up a bad pot or one that is going, but it may uncover a bad gear.

That's about the best you'll be able to do.

It depends upon the failure.

If the servo stops fully deflected, you may not be able to control the plane. If it stops operating in a neutral position, you may not have any problems.

A servo can always fail in use, so that's the risk you take every time you fly.


Strangely I too have had the MOST failures occur with Hitec's over any other brands INCLUDING the cheap Chinese knock offs.

some good questions here.....as everyone has said you can mix analog and digital on the same plane.....but not on the same control surface like a digital on 1/2 of an elevator and analog on the other....you always want the same servo on the same control surface...ie 645's on both halfs of a control.....
I set up my bipe with 4 ailerons servos...with both lowers on one channel with a Y and the upper half on another channel with a Y....that way if I have a servo failure I have at least on good set of ailerons......

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