Remby

My Feedback: (3)

Futaba servos work well, only one failure from a crash, the rest all still work, even the 3110's that they quit making a number of years ago.

The 3114's are what work well for me. I prefer "barn door" over "strips", using two servos on a "Y" wire in the wing.

All are tied into a 1/16" plywood cutout of the needed size, cut to surround the servo. Secured the servo into the ply with a strong nylon thread. Then, holes are drilled further out in the plywood servo adapter to allow for grommets, then mount this assembly just like a larger servo. This works much better then trying to force/fashion the grommets into the servo itself.

The two wing servo system also needs very small linkage setups, lowers the moving mass/weight.

Andrew

I've taken a slightly different approach from Remby and Yuu.

Most of the grommets I've found are too hard for micro equipment and offer very little in vibration protection, plus they can be hard to fit. I use silicon fuel line or the silicon insulation from battery wire - the ultra flexible wire that the car boys use. I prefer the insulation since it seems to be even softer than fuel tubing. Since most of the micro-servos have notches for mounting, I'll dremel the notch wide enough to have a very light friction fit over the insulation. Cut a piece of tubing or insulation a little over 1/8" long (pick a ID so the servo screw easily goes thru) and mount the servo. Either use a spacer to hold the servo off the board or just hold the servo off the rail as you tighten the servo screw. Tighten just enough to allow the tubing to bulge a little above and below the servo mounting tab. It's not necessary to really crank it down since the forces are so low - just enough to retain the servo. I think the softer silicon absorbs more vibration than any grommet I've seen and you have some control over how tightly the servo is retained.

Edit: This is almost identical to Yuu's method, just with a single piece of tubing rather than two.

andrew

R/C Phile

I did replace the elevator servo with an HS-65HB as Mr. Cox suggested. It has carbonite gears and ball bearings, has more torque / is faster / has an indirect pot but still does not have grommets..

It along with the rudder servo is mounted on the tail a couple inches from the rudder / elevator. Since being away from the engine still was not enough to prevent vibration related issues I mounted both of them using the Yuu's fuel tubing trick (It isolates completely and looks pretty slick).

At $25.99 from the LHS (AtlantaHobbies) I think it's a great value it makes the reponse crisper and looks far better made than the HS-55 and it's only a 5 grams penalty. I think I'll replace the aileron servos with the 65's as well. Size wise they are almost exactly the same as the HS55 just a sliver longer.

If you want a micro that comes factory made for the grommets the HS-81 is a little stronger / faster / cheaper than the HS-65HB but is also bulkier and another 5 grams heavier..

EDIT, I guess my approach was closer to Andrew's as I did cut the tubing to make "C" out of it on its lenght. See Attached picture of how it turns out. (I took it after flying yesterday, it's a little greasy lookin' )

fit90

Had a JR DS285 fail today.  I was really surprised.  These have performed very well for me up to this point.  I think that I am to blame for this failure though.  The servo is in a Sig Hummer.  At my field we have aircraft starting tables that are for bigger planes.  They have two boards that extend up from the table to keep the plane from moving.  On the typical .40 size plane the wing's leading edge rests up against these boards.  On the hummer I put the wing in front of these boards and often times push the plane back into them when starting with an electric starter.  When ever I catch it happenig I make a little mental note to myself to never let that happen again.  Then I launch the plane and completely forget about the mental note.  Any how, I typically smash the left aileron against the plane stop and the servo that failed was the aileron servo.  It suffered a gear failure shortly after a reverse half cuban eight.  With no throttle I really thought that the crash was going to be spectacular because the engine is probably turning over 30k in flight.  I was happily wrong. I was not able to prevent the crash but was luckily able to achieve a level pitch attitude for the crash.  Repairs will be fairly minor considering all things.

All things considered, it was still a great day at the field.

tewitt1949

Our club members won't use HS-55's any more due to gear problems. I personally quit using them about 3 years ago. Every time I turned around the gears were out.

hllywdb

I have dropped all my HS-55's and use them only as throw aways on my 1/2A full contact combat planes. I have far better luck with the Hong Kong cheapies than the 55's. Any thing that I don't want to lose I use Futaba's and pay the $$$

R/C Phile

As you may have seen on my other "Flying on Skis" post I had another HS55 aileron servo go bad. This one went Kaput in flight, all attempts to control were futile so all I could do was cut the throttle and watch it go straight in..

Amazingly enough, even if it went straight down from about 80 feet, the little bird took the hit amazingly well and with a little patching-up I was able to fly again the same day [8D]

Notable details:

- This one was mounted with grommets and had low flying time

I have 10 HTX 900 comming in a few days, that's what I'll try. At about 3 bucks a piece I just won't fly them very long.

dieFluggeister

All of my 55 failures have been because the control surface was moved in the hanger or on the way to the field and stripped the gears - never in flight. I have made it a practice to check my servos before every flight, but I have also made it a practice not to buy any more either!

R/C Phile

I replaced another one yesterday (Before it caused any grief).

This time: The aileron servo on my electric Astro 010 powered 3D foamy plane.

Same failure mode as all the others : Nothing wrong with the gears, the control potentiometer was going bad and losing it's ability to center. Like dieFluggeister I check the all servos before every flight by wiggling all sticks (Have done that since the 80's) and there was enough suspect flutter movements to stop me from flying. (I had checked them before the in-flight failure on the Little Extra as well but somehow the failure came at once..)

So much for the claims of HS55's lasting a long time on electrics blaming the pots going bad on glow vibration.

Granted, this plane has probably been a couple hundred flights using this servo, but this power system is as smooth as they come. Astroflight motors cost an arm and a leg because they are all hand made, use the best quality magnets, and also use larger / higher grade bearings than most other electric power systems. In addition, this one is a geared unit spinning larger props at very low RPM's.

To top it all off: everything is mounted on vibration absorbing foam since it's after all: a foamy..

I will replace the remaining HS55's I have on other planes in the next day or so and I'm done with HS55's