8711 or 5955

[hillmanr2]

	Quote: Originally Posted by Wayne
	Use what your comfortable with. Its all good stuff. Some like programmers, some like matchboxes and some like sub trim and ATV.. I'd like to do a test though one day... Take an average pilot and have two of the same planes in the air. One has a "perfect" set up and the others set up is "off" or not "perfect" I'd be suprised if anyone could tell the difference or determine which one was "off" in the air. Thats where it matters doesnt it??

I'll let you know.
The 8411's are going in my h9 27% to replace the 5955's on elevs and 5945's on the ailerons. I know that plane inside and out. I will be flying it with 8611a on rudder and 8411's all the way around.

[Wayne]

	Quote: Originally Posted by sweetpea
	You can't bring logic into this discussion Wayne......are you crazy?

Just trying to make the point that no matter how well we set up our planes, some better than others, getter better in this hobby is about burning gas.

[Shoe]

We use JR's.

[krayzc]

i am getting ready to try some of those 5955 on my Ultimate i think i will be pleased since i am currently running 4-5645 on those surfaces. Yeah lock and hold baby!

[wingburner]

TBM SERVO AND SERVO EXTENSION TESTING
** TBM SERVO TESTING: TBM conducted its own servo torque testing using the pictured equipment. We monitored the voltage at the Rx, the voltage at the battery, the amp draw at the battery, and the torque of the servo. We used a TBM 2-cell LiIon battery with a MPI Miracle switch (which has a built in 6v regulator). We tested other batteries and other regulators from Fromeco and Smart-Fly and there was no difference in the performance of the 1 servo. We were concerned with moving torque, not holding torque. We are interested in the power available to move a control surface into position. The most powerful servo, and the most power hungry was the JR-8711. It drew as high as 5 amps initially though the load dropped to 4.2 amps in less than a second. Having 13 of these on a very large plane like a 50% plane leads you to conclude that there could be a momentary current draw of 65 amps if all the servos were stalled. To put this in perspective, most of the circuit breakers in your home are 15 amps, and the best 4-cell LiIon has a burst output capacity of 18 amps. IN REALITY a plane with 13 JR-8711 servos will never require 65 amps. We estimate based on some testing that 50% planes will typically pull a peak of 40 amps, 40% planes pull a peak of 20 amps, 35% planes pull a peak of 10 amps, 33% planes pull a peak of 8 amps and 30% planes pull a peak of 5 amps on a routine basis. NOTE: I am not concerned too much about the torque values I obtained being lower than the stated torque values of the manufacturers because they are publishing holding torque, not moving torque, and their testing methods are different. I do feel very confident that the relative amount of torque difference from servo to servo is accurate and should be used to determine the servo you should use in your aircraft.

TBM SERVO ENDURANCE TESTING: TBM conducted its own servo endurance testing using the equipment shown above. We found that the first 1/10 of a second that the servo is used that the torque is at its maximum. The performance then degraded substantially over the next 60 seconds (of intermittent use), and stayed at that lower value for the duration of the testing. For instance the JR-8711 has an initial torque of 358 oz-in, and after 60 seconds (of intermittent use) the case heats up to 120 deg F and the torque drops off to only 280 oz-in! This is a decrease of over 20%. I regret to report that the Hitec HS-5955 lost 40% of its torque by dropping from 248 oz-in to just 152 oz-in in about 60 seconds (of intermittent use). To define intermittent use: I did not simply stall the servo for 60 seconds to see what would happen. I operated the servo as if I was performing knife edge passes along the flightline and knife edge loops, so the servo was cycled on an off and was stalled for no more than 8 seconds at a time.

HITEC HS-5955 - 152 oz-in
JR 8711 - 280 oz-in
The data above is under the following conditions, and other testing may show different results. These values were derived using the test method and equipment shown above. These torque figures are after a minute of hard operation which causes the servo to heat up substantially. This is the power that we measured that you can count on for the long term.
JR-8711 vs Hitec HS-5955 in actual use. This test started with using one HS-5955 servo in my 35% Extra 260. I had just enough rudder power to perform a knife edge loop. However I noticed that the rudder lost power later on in the flight. Apparently this was due to the servo heating up and losing power. I added a second HS-5955 servo and the difference was tremendous. Rudder authority was like a foamy plane. I then switched to one JR-8711, and there was no detectable change to the rudder authority compared to the two Hitec HS-5955 servos. This confirms that the above test results of 152 oz-in vs 280 oz in is realistic and usable.

TBM SERVO EXTENSION TESTING: TBM conducted its own servo extension testing using the equipment shown above. We found that adding a single servo extension (22 gauge with universal connectors) between the Rx and the servo will cost you 1.5% - 5% of your power to that one servo. Adding another extension will cost you another 1.5% - 5% and so on. In one of the many tests run, I put ten 6"extensions in series and measured a total drop of 15% of the maximum torque that a single JR-8711 could put out. In another test, I put ten 48" extensions in series (40' of extensions) and found the drop in power to be 55%. Therefore losses due to servo extensions is a combination of plug losses and wire resistance losses.
POWER LOSSES IN SERVO EXTENSIONS
SERVO EXTENSION LENGTHEXPECTED TORQUE LOSS6"1.5%12"2%18"2.5%24"3%36"4%48"5%
WHAT'S THE BOTTOM LINE OF THE ABOVE TESTING?:
SERVO POWER: You will see a significant drop in power of servos under constant use HOWEVER you will only notice this drop in the performance of the rudder. The rudder is the only surface which is pushed to its limit for extended periods of time. No matter what, the first time you use your rudder it will have more power then than later on in the flight. If your first maneuver is a knife edge loop, the second knife edge loop will not have the same power available to the rudder. Therefore, overpowering of the rudder is necessary so that you don't need full servo power to do a knife edge loop (or knife edge pass or whatever you use the rudder for). Of course for those who don't use the rudder much, then the drop off in power is of little consequence to you, and you won't notice any difference.
SERVO EXTENSIONS:
With proper servo sizing, you will not experience any difficulties using extensions.
* Never use extensions between the battery and the Rx. If you need more length, splice in additional 18 gauge wire.
* Use the shortest length extensions possible.
* Use one long extension instead of 2 or more shorter ones.
POWERING YOUR PLANE: The servo power required for your plane's control surfaces varies with the following:
The Obvious:
* airplane size
* control surface size
* mechanical advantage of linkage
* control surface throws
* airplane speed
The not so Obvious, but equally important:
* current available to the servo under load which can vary with battery, regulator, switch, servo extensions, plugs and more.
* the reduction of torque due to the servo heating up or wearing out
* the weight of the plane. The more weight, the faster it must fly, and the more servo power is required.
NUMBER OF SERVOS PER AILERON:
* For 85cc and 100cc planes, if the aileron is fully sheeted, you can use one servo. If the ailerons have lightening holes, you must use two servos.
* For 210cc planes, if the aileron is fully sheeted, you can use two servos. If the ailerons have lightening holes, you must use three servos.
NUMBER OF SERVOS PER RUDDER:
* For 150cc planes, there are many options, and the weight of the planes available vary considerable, as do the sizes of the rudders. If you use a push-pull set up in the back of the plane using pushrods, you will gain power, and have a more effective rudder versus using a pull-pull set up. The problem with servos in the tail is weight. All planes are tail-heavy, so adding weight to the tail by putting servos in the tail must be accounted for. With the Extra 260 and Yak cowls not having nose rings molded into the cowls, and thus the cowls being open in front, you can move the engine out without it looking bad, and more easily counteract the weight of the servos in the tail. Most manufacturers do not offer servo mounts in the tail, so you need to make these yourself. A Seiko servo has tons of power and is less expensive, though it weighs 10 oz plus an additional 5 oz for a separate 3-cell battery.
SERVO SUGGESTIONS FOR MAX PERFORMANCE
AIRPLANE SIZEAILERONS
(see note above)ELEVATORSRUDDER50cc(1) HS-5955 each(1) HS-5955 each(1) HS-595575cc-85cc(1) JR-8711 or (2) HS-5955 each(1) HS-5955 each(1) JR-8711100cc(1) JR-8711 or (2) HS-5955 each(1) HS-5955 each(1) JR-8711150cc(2) HS-5955 each(1) HS-5955 each(2) JR-8711 or Seiko210cc(2) JR-8711 or (3) HS-5955 each(1) JR-8711 each(3) JR-8711 or Seiko
Where I am recommending the HS-5955 servo above, I do so because of the following:
* The HS-5955 servo is not much more money than the HS-5985, and with its titanium gears and higher torque, it is well worth the money even if the HS-5985 will do the job such as in 50cc ailerons and elevators.
* You can upgrade from the HS-5955 to the JR-8611 for more power but the drawback to the JR-8611 is that its gears wear quickly and you will have gear slop issues.
* You can upgrade to the JR-8711 for even more power, but you will not notice the change because the HS-5955 is already an overkill in the above situations.

[rede2fly]

ok ill throw in my opion. i use nothing but jr. why because they allways work. and horizon has the very best customer service that i have used. jr servos have allways worked for me. never have i had a pot go out. unlike futaba 3 in less than 1 month. (not bashing just stating facts). i have tryed the " cheeper hitecs" out of 4 of the very same servos, no 2 centered the same or throwed the same side to side. these you could not use a programmer on. 645's so ill stay with jr and know in my head what i have. and the quality that they strive for. and no i dont work for ,or sponsered by anybody. quality is quality. and hey what these are put through wear and tear is expected. somone has to be the leader and seems to me that jr allways steps up to the plate. then the followers come out. just my 2 cents, which by the way isnt worth anything. but i did stay at a hoilday express. oh yea hey giant dudes dont close this tread. let it run its course.

[AndresAM]

Wingburner,
Interesting results, I hope they can run the same tests when the new Futaba 9156 becomes available.
Andres

[krayzc]

My 1st ever 5955 have arrived. I cannot believe how tight these servo gears and and to hear you all say a year later they are still just as tight is something to see. I have at least 20-8411 that are in 3 other planes. I have never replaced the gears in those. I cannot tell in the air any slop not to say they are as tight as they were when they were new. I will be trying one of these on the rudder of my new H-9 Cap from the good recommendation of a FG Cap owner. I will be pulling the 5645 off the ailerons on my Bob Godfrey Ultimate and replace those with the 4-5955. I look forward to installing and flying these babies.

[khedge]

Well you will love the 5955 i will be running 8 up them in my 31% Edge. I have had nothing but good performance out of the hitecs 5955. I would like to try the 8711 jr's, but I use can pass up the programing that hitec servos have.

Krayzc<

In one of your pic you have 9X jr radio, when did that come out? Is it similar to the 9303?

[krayzc]

khedge,

I bought the radio from down under about a year before it made it to the USA. I think it was 399.00 at the time seems to be I picked it up on the net around feb 04. Its been good to me the difference is it takes 20 models i think the stateside version takes 30 models.

[krayzc]

well now I am getting ready to try 2-8711 on the rudder of my latest project nice and strong out of the box those 8711 . I have out fitted most of my smaller birds with 5955 on the ailerons and kept the 8411 on the elevators. I have not touch my 40% that has all 8411 on it. Those are still working great for my needs. I think my ailerons are the taxing surfaces on my birds so lets give them some good gears ......

[jongurley]

Do you guys think 1 5955 will be enough per elevator half on a Carden 40% Extra330,,, I will be using the smartfly powerexpander with A123 Fromeco batteries,,

[IMACmike]

When I move the sticks and the surfaces wiggle, I'm a happy camper. I'm with Wayne on the "ability" to see a "huge" difference (a slight upper elevation crosswind is usually missed by most). I know that all servos will wear on the pots and gears, regardless of who makes them, and maintenance needs to be done. JMTCW

[flyin woodbutcher]

	Quote: Originally Posted by jongurley
	Do you guys think 1 5955 will be enough per elevator half on a Carden 40% Extra330,,, I will be using the smartfly powerexpander with A123 Fromeco batteries,,

No way, they will get hot and give up the goat. You will pull and one side will be weak and your going up wings not level.

FWB