Originally Posted by cyco

today installed my new rudder servos, 2x 7950th -no glitching -just working perfect.

Emcotec DPSI 2001 Servos @7.4V direct, 0.35mm wires, twisted.

centering, speed and holding strength -compared to the 5955tg were awesome...

next days i will set up the rest of the servos.

regs,

Chris

now finished programming all 8 Servos -absolutly smooth operation, no glitch or jittering -just working perfect.
awesome speed and strenght....


Chris

HI I have a EF 110'yak 54 on a bme 116 Its on two 7955s on the rudder now and will try 1 7950. I have a smartfly sport on it and 2 2300 A123s.

Im also tempted to take out the 2 7955s on the ailerons and do 1 7950, is it a bolt on thing? no need to reinforce the ailerons? ok for imac? Ill use the inner servo location right?
I asked Chris from Extreme flight and got a big no! on this!

will rx batts last longer with the fewer servos?

The power draw should be about the same, assuming your two servo setup is well matched, and that they're not fighting each other.

The aileron is a huge surface, so if anyone is contemplating one servo, they really need to make sure that the surface is stiff enough to handle this.

youll need to replace 2 against 2. but the power of the 7950th is awesome.

even the power "fuel" consumption is awesome - 3 flights about 5-8 min. on flightshow (windy condition, 3D style) a day taking only at 1000-1200 mah pro battery.
(9 Servos -8 7950th and one 5955tg).

snaps are like "bang", rudder power in knife edge (2 servos) is awesome, now you can fly a 180° knife edge spin.....

Chris

ok thanks guys installing
1 7950 now took 2 7955s from
the rudder

Originally Posted by toti_ducati

HI I have a EF 110'yak 54 on a bme 116 Its on two 7955s on the rudder now and will try 1 7950. I have a smartfly sport on it and 2 2300 A123s.

Im also tempted to take out the 2 7955s on the ailerons and do 1 7950, is it a bolt on thing? no need to reinforce the ailerons? ok for imac? Ill use the inner servo location right?
I asked Chris from Extreme flight and got a big no! on this!

will rx batts last longer with the fewer servos?

i would stick to what extremeflight recomends on this. the wings and ailerons are huge and need both servo's keep the aileron straight. believe it or not but imac can be harder on ailerons than 3d. imac your at a pretty good speed and have all that resistance. especially in snaps. 3d low down hucking your really not stressing the ailerons as bad. just deflecting prop thrust. if a certain surface requires say 3amps to move it if you have one giant servo or 2 smaller ones it will only still take 3 amps. that is all the power that is needed to move the surface.

I agree, stick with 2 servos on the wings. One 7950 on the rudder is fine, been flying my EF YAK like that for the last 7 months and there is plenty of power. May still be more precise with 2 on the rudder, again it is a massive control surface.

i've read about 40 pages of this thread and it seems like the consensus is that the signal booster from spektrum will cure the problem? i'm also convinced that it at least in part, has to do with the long extensions. when i plug the servo directly into my ar7000, no problems. but when it's plugged in through the 36" extension (24 gauge), then it twitches and jumps all over the place. (my 7955 also does the same thing).

has anyone tried the spektrum booster and NOT have it fix the problem? does it have to be the spektrum brand specifically?

has anyone tried going to a thicker wires (22 gauge) to see if it helps?

Horizon Signal Booster

http://www.horizonhobby.com/Products...x?ProdID=SPMCP


Hitec says use them on any lead over 24". There are folks that are working Ok without them.

Preference is to use 20ga twisted wire. This info was in regard to the Powersafe receivers, JR922 and JR1222. Call Hitec and ask about your specific installation.

They have excellent support and techs are wonderful to speak to.

You can also get boosters from Emcotec USA. German based company.

Having a similar problem with a 7950 I am helping a friend out with. When it is plugged right into the receiver unregulated with a lipo, it works no problem. When you plug it into any extension (tried a 24" and 48") the servo jumps violently back and forth every few seconds. 22ga wire. None of the other 7950s on very long extensions do this, just one of them. I even checked the voltage on the long 48" lead, and getting 8.0v on it back there. I am going to try to reset it and see if that helps, but guess it will have to go back and try a new one. Like I said, tried 5-6 others and they are fine, just this one.

Originally Posted by Patrick H

I am going to put two of these on ele using A123s and jr 922 so I just did some tests. No conciliation for the guys having problems or maybe there is.

jr 922 powersafe rec.

7940 hitec servos, same as 7950 except for gears I believe.

240" + 26"extensions, yes that is right 240". Made from "22g" wire but I cant tell the difference between it and 20g wire sold by hitec. It is the same size as that on servo.

A123 batts no glitching on two servos each connected for 40 mins each with periodic playing trying to replicate symptoms described in this thread.

Out of curiosity, 2S 5400mah 40C lipo with voltage of 8.1V. Two servos connected for 15mins each with periodic playing trying to replicate symptoms described in this thread.

All smooth and rock solid. I just placed the order for the two 7950s.

7950's on 44" extensions have been perfect for 40+ flights.

Sounds like it may be iindividual servos.

Just tried resetting the servo, no luck. It still swings back and forth violently when plugged into any extension, regardless of length. Guess this one is going back to hitec. Its fine if plugged right into the rx, but not any extension.

QC......problems?

problem solved! i just peeled the wires apart on my cermark un-twisted extension and twisted them. that's it and twitches completely went away. just to make sure, i unplugged my newly twisted extension and plugged in my un-twisted extension, and again the jitters and twitches came back. i've now twisted all my extensions going to the elevators and rudder and all surfaces are rock solid. i'm amazed! what a night and day difference with such a simple solution!

Ok running out of ideas here. Of the 13 7950s we have, 4 of them are doing the twitching and banging back and forth. Running unregulated lipos on them. Hitec Aurora & Optima 9, and a smart fly power expander. Does not matter if the power expander is used or not, extension or no extension, does not matter. Do these just not work well on freshly charged 8.3v lipo packs?