Missilemech

Help! I’m a new member and am having a problem on my first build.
I converted an an E-Flight PT-19 Trainer ARF with a Saito FA 30s init. No Problems there. But I keep losingAileron servos left & right – literally. Equipment is all Spektrum – DX6iTransmitter & a AR 6115e receiver with DSP-75 servos & a Hydrimax 2000Mah battery pack. Every time I have runthis plane - only on the ground so far- I’m losing one aileron servo or theother after about a half hour of operation. I have eliminated all unnecessaryconnections – the 2 6’’ servo extensions, (just in case voltage drop or currentdraw was a problem), I managed to get them to a New Y connector and installed 2 more new servos as well. It hashappened 4 times now and lost the 5[SUP]th[/SUP] one today, after about a halfhour of running the engine on the ground. All servos are mounted on rubber isolationdampeners & I even used a new battery, fully charged. When this quit today all other servosincluding one aileron servo, were still working fine. Just like every time before. The problem seems to gofrom side to side. No consistency. Does anyone have any idea what could be doingthis? I’m getting tired of fishing servo leads thru the wing not to mention thecost of all this!

krokodyl

It might be a good Idea to give spektrum (horizon hobby) a call, and see what they say.

Here are the only things that I can think of that could be causing this problem:

The receiver might be faulty, causing one port to do something weird to the servo. Very unlikely, but I guess it's possible. Maybe vibration? Probably not though, because then all the servos would be quitting. So, if you have another receiver, try it, and see if that fixes the problem. What battery are you using (how many cells)? When you take the servo out that is damaged, and power it up, what does it do? Do the servos still die if the engine is not running?

Hubert

Missilemech

Thanks Krokodyl. I don't have another receiver to test, but I will give horizon hobby a call. The servos (others) work whether the engine is running or not. The battery Is a new Hydrimax "AA" 5 cell type - 2000 Mah. As far as testing the servos I have taken out - I have not tested them yet. Thanks for your feedback. I will call HH tomorrow & see what they say. Thanks.

Zeeb

My Feedback: (41)

Well you've got some issues identifying what you have? There is no PT-19 made by E-Flite according to their website and Horizon's website. There used to be a control line version but all you can buy now is a replacement wing. The Saito number you list is a bearing. The servos you list are out of production because they had problems with them and last, I would NOT use a AA size cell in any brand of NiMH chemistry battery and Hydrimax is probably my least favorite.

oliveDrab

I've used Hydrimax 5-cell and 4-cell NimH's for years ... never had a problem with them. Can you ditch the Y-connector? Plug each aileron servo into it's own channel on the receiver.

Missilemech

Zeeb - This is an E-Flight PT-19 that was made a few years ago. It could be set up for RC or Control line. Got it from Horizon Hobby. The Saito engine is a FA-30s, not a bearing p/n. And the hydrimax batteries are fine 5 cell units.

grotto2

My Feedback: (2)

How long do the servos last if you don't have the engine running?

fizzwater2

My Feedback: (61)

at servodatabase.com the reviews of that servo are not very favorable. Also, the specs are listed ONLY at 4.8V, there are no 6V specs given, which leads one to believe that a 5 cell battery (6V) may be too high of a voltage for them, which drastically shortens their already short lifetime.

Might be better off investigating some replacement servos that are more up to the job. Buy once, instead of repeatedly.

Perhaps something along the lines of this one? There are several out there that will work with 12V and might last longer.

http://www.jramericas.com/174415/JRPS188HV/?pcat=554

pilotpete2

Excellent catch on the fact that these servos are only rated for 4 cell operation.
Swapping out the 5 cell for a 4 cell pack may help.
Personally, I thinking that sub micro servos, especially 7'.5g sub micro servos are for use only with electric powered planes IMHO 12g size servos with metal gears would be a better choice.
Pete

AndyKunz

The effects of vibration on the tiny gearfaces is horrendous on a nitro model. Those are servos for small electric models - putting them on a .30 nitro is going to kill them in short order.

Andy

fizzwater2

My Feedback: (61)

I agree, you'd be better off with some larger, more robust servos with that 4-stroke on the front.

Zeeb

My Feedback: (41)

Okay it sounds like you have the situation well under control, I won't bother to try and help anymore. Good luck.