Hello All,

I have been flying a gremlin for several months, and have had 2 servo failures...... The servo won't center sometimes, and it's jittery.When this happens the servo is very intermittent. It has always been the servo that gets the most exhaust oil...Pretty sure it's the servo; I tried another receiver and another transmitter, and the problem didn't go away. I'm using the cheap hi tech Hs-300 servos.

Anyone else had this problem ??

Dumthumb

I don't think it's the oil. I have been flying Gremlin(a lot) for over ten years,I get lots of oil on them too and it has NEVER made one fail. I have had problems with the HiTec servo's doing that same thing in my Raptors.

Dumbthumb,

Maybe its the exhaust residue, maybe not. To protect the gear from the exhaust goop that does get in there, I cover most of the cutout in the top of the fuse with packing tape.

Its light, quick and easy to do.

HTH,
D

Dumbthumb,
I have had two Hs 300 servos fail just as you describe. These were not in my combat plane nor were they covered with oil. I don't buy 300's anymore I stick with the 425's.
Chap

I have the same problems with the HS81MG's.

Sounds like what happens to my HS-81's. When that happens, following Hiteck's instructions, I open up the darn things, carefully open the feedback pots and spray them with tuner cleaner and exercise them alot. Repeat 3 or 4 times then reassemble carefully making sure they go back together in the same orientation that they came apart.
This procedure has worked for me on 4 servos so far.

JESTER

solution to the oily servos

Dumthumb
Sounds like a bad servo to me,had an old servo do that to me drove me nuts finding it.
CORO KID

Man that is one GREAT looking Gremlin. You use it in combat?

Only when I'm looking for Bin Laden on Sunday afternoons!

Seriously, no.

I have another one used for combat. I just love the way they fly I had to build one for a Sunday flyer.

The wings are sheeted with 1/16 balsa. Power is YS45 turning APC 11-7 at 12800 rpms. Muffler is Dave Brown unit bought years ago. In the instruction sheet they said to add tube for extra 200 rpms. It sure keeps the plane clean.

I race 1/8th scale nitro on road were the servos are subjected to a lot of abuse and gobs of exhaust residue and spilt fuel during pit stops without problems on my Airtronics servos. Many people have had problems with the Hitec servos(esp. centering) along with some other complaints...

Due to the low cost nature of Hitecs equipment, maybe in combat this can be overlooked. Maybe re-sealing the cases or diverting the exhaust away from them may help and trying to keep the vibration down on the servos mounting point could be benificial. If you're replacing servos often it would seem the savings would not be so great compared to ONE good servo?? just my 2cents.

I had a Futaba 3003 fail in my profile plane. It was my throttle servo with only about 20 flights and was always getting amount of exhaust residue blown on it. I have never had a throttle servo fail so I only can assume it must have been the exhaust residue that caused it to fail. I made a lexan shield for the new servo and so far so good.

When I opened up the HS-81's BTW, I found no evidence of any oily residue anywhere inside the case. And if you opened one yourself you would see that the route that oil would need to take kinda rules out oil getting in the pot. What I'm thinking is it's the vibration that is causing a poor contact in the feedback pot whether it is abrading one of the surfaces (more likely the resistive surface) and the resulting dust causing the problem or the spring tension on the wiper is decreased causing intermittent contact. I'm leaning toward the first explanation right now.

OR... I could be all wet,

JESTER