JEFFRO503

My Feedback: (9)

Guys.....i have been meaning to post this for sometime. I know almost everyone on here that is looking for high torque type servo's and end up using the Hitec brands , for some reason , always use the 5955's........why? In the hitec chart comparison the hitec 5995 is quite a bit stronger at the same voltage , with titanium gears just like the 5955's.


I understand that the 5995 is listed as a "robot servo" , but the dimensions are exactly the same as the 5955.


5955 @ 4.8V is 250 oz
5955 @ 6.0V is 333 oz


5995 @ 4.8V is 333 oz
5995 @ 6.0V is 417 oz


I was curious to see what the difference was , so i bought one. I put it on the rudder of my little funtana 100X , and HOLY CRAP.....can just about hold the rudder , wiggle the stick and the whole plane will just about want to scoot across the table. I have gotten about 18-20 flights on it so far , with no glitching and smooth as silk operation.

what's the reasoning for using the 5955's instead of the 5995's? don't get it.


Jeff

BTerry

My Feedback: (8)

Hitec says the 5955 is better for airplanes because it has better resolution. That is one reason to use the 5955. Torque and speed are useless if the resolution is poor.

BTerry

My Feedback: (8)

also you can run into problems if the ATV is set higher than 100% or so because the total signal range is narrower than on airplane servos (1100 to 1900 microseconds versus 900 to 2100 microseconds) and the travel is set to 180 degrees out of the box.

3D Joy

I think your specs are wrong. They are supposed to be the same servo. The 5995 is rated at 7.4 volts (close to that) hence the higher torque.

krayzc-RCU

My Feedback: (31)

[8D]

Hammbone

My Feedback: (309)

Both of these servos use the same motor. The 5995 is not stronger it is just rated for 7.4v use on robots. Hitec does not recommend 7.4 volts for airplane use, so the 5955 is rated at 6v.
The specs for these servos are misprinted in some places. They are the same motor though and the same strength. Use the one intended for airplanes on airplanes and the one intended for robots on robots.

Jim

mglavin

My Feedback: (31)

The HS-5995 robot servo works with factory programmed parameters of 180 degrees total servo angle with a narrower drive pulse or control signal as compared to aircraft servos with 120 degree total swing. The performance specifications are the same on like voltages. The 5955 also comes with a CNC aluminum heat sink center section and affords the aero modeler greater system resolution too....

HS-5995TG:
Operating angle: 90 Degree one side pulse traveling 400usec. Direction: Clockwise/Pulse Traveling 1500 to 1900usec

HS-5955TG:
Operating angle: 60 Degree one side pulse traveling 600usec. Direction: Clockwise/Pulse Traveling 1500 to 2100usec

Richard D Bahmann aka/Wrongway

My Feedback: (42)

Mike,

The part about the heat sink sparks a question. After a recent succession of 35 minutes of hard flying (2 @ 10 min 1@ 15) on my Extreme Flight 88 Yak, I found my battery warm and the 5955 warm as well.

My question is what kind of temps might I find after working one of these servos hard on a 6v system? What temp do I really get concerned. I shot the servo with an IR temp guage and got 115 degrees.

Thanks in advance for your help.
Richard

JEFFRO503

My Feedback: (9)

Welp........that all makes sense for sure. I couldn't find the specifics like you guys did on the "resolution" and stuff like that , just mainly the voltage and and torque , and overall dimensions. Thanks for all the info guys. I think i'll leave the 5995 in the rudder of that funtana since i ain't really into robot's........just planes. Thought i would at least try it. Thanks again.


Jeff

Tired Old Man

My Feedback: (1)

Resolution is, IMO, more important than speed and torque. I want my servo to go where I want it to and not going looking for a spot close to where I told it to go. I'll be buying some new servos pretty soon for another plane and the 5955's will be the direction I take.

Robots are for work, planes are for play, so no need for a 5995.

Michael,

Interesting question about servo temperatures. I easily understand a battery getting warm, especially if has had a high draw placed on it. Is it possible that someone may have some servo binding taking place or not using enough servo or battery for the job?

Richard D Bahmann aka/Wrongway

My Feedback: (42)

Good question Silver on binding, etc.

The battery is FAUP 1950 on smart fly switch (deans in 2 jr plugs out) and the rudder is the recommended for the job on the above post. All the guys at the field agree that the servo is not binding as in cables too tight.

Some might think it silly but I ran the servo function on my Futaba 9C for 20 minutes and saw about 105 degrees from a cold soaked 75 degrees. IMO why would they put a heat sink in a servo unless it is making heat. My question is more about norms and when to become concerned.

{EDIT Forgot to mention that the servo sits just aft of the balsa pipe tunnel. The plane is flying on a comosite pipe.}

Thanks again in advance for any help.
R

Tired Old Man

My Feedback: (1)

I don't think 105 is bad. Any electrical product performing work creates some heat. The more work it performs the more heat it will create up to a point. Personally I think that in about 90% of installations the heat sink is there more for flash than practicality, but it's there if the conditions need it.

The pipe adds to the heating to some degree almost certainly.

Uncle Sir

interesting post. i have never really thought of that.
I tested my 5955's on my 30%er. Ran them hard in the garage for 15 min. (my fingers go tired!!!!) All read between 91 and 98 degrees. I am pretty sure your op temp was normal. Electronics that are compact will maintian and gain heat quicker (harder to disipate what they have already created. Most ICs and boards handle much more temps without failure (140-160). After all it takes heat to turn the 0s and 1s on in the IC and chips ect..

10000110111001110100101010001011101000 (that means i WILL move up to ultimate this year (yeah right)

BTerry

My Feedback: (8)

Per Mike Mayberry of Hitec, the 7.4 volt rating is only because robots can tolerate a shorter servo life span than airplanes can. You can also run the 5955 at 7.4 volts and expect 30% shorter life, the same as the 5995.

Tired Old Man

My Feedback: (1)

I don't go into servo voltages anymore. I'm one that's well aware that many servos can be driven at higher than the publically listed voltages, but telling people about it always kicks over a can of qustions of what happens if you do it. Then they want to know about the life or wear, or speed, or increased torque poyentilas. Then if something goes wrong they blame you for it.

mglavin

My Feedback: (31)

I haven’t found the need to measure the temperature rise on servos, as noted 105*F is well within the atypical electronics range. As noted I'd be concerned when things got above 150*F. Several variables are in play other than inadequate batteries and or binding, such as power distribution and excessive electrical losses through multiple connectors and or connectors that are either low quality, mismatched, tin plated, dirty or damaged

The best possible system setup IMO involves the use an inline amp/voltmeter, these devices are readily available, inexpensive and display a single servo and or a gaggle of sames actual current consumption while stirring the sticks. This is an invaluable tool for setting up any model and takes the question out of binding or note? Some will not if they look hard enough that there setup may pull more current in one direction, any suggestions for the how and why of this anomaly?

MustangAce

My Feedback: (3)

You know just sitting here I'm almost at 100 degrees Really the temps are interesting but shouldn't be of concern. After all, that is why they have a heat sink on the case. If you wrapped the case like is done on some of the small electric planes then it could be a problem.

Tired Old Man

My Feedback: (1)

Michael,

I'm going to go ahead and ask for the why. In a horizontal application the weight of the surface plays a large part in that anomaly with an unbalanced surface. I see it in my own stuff when the surface is being lifted rather than lowered. Turning the surface over usually reverses the current draw. In a vertical surface I'm thinking unequal ranges of motion may also play a part.

So what's the answer?

rmh

As Brer Galvin noted - the batts n wires n connectors can really affect things .
In search of the Holy Grail of Power for the servos -- I setup my trusty Astro Whatt meter and a small voltage readout LCD (EXPERT 501) and hooked up batts to my various models and started reading numbers .
The big problem is --batteries .
If you believe the size of a battery determines how much power it puts out - be prepared for a revelation.
In today's world of better living thru chemistry- the entire battery market has changed --a lot.
I have small 1400ma (Intellect) cels which will easily put out more power (WATTS) than some older 2700 ma cells.
Also my new 123 cells (3.6v per cell x2300ma) ) simply pass up anything else in raw output.
I now use two of these as a rx pack in all my stuf -except for my 42% which gets a pair o packs
starting voltage is 3.6 per cell - drops quickly to 3.3-and for MY use , is running at about 3.3--3.1 during a flight -full loads .
So what?
The so what is that no matter how hard the servos suck at power - the voltage stays up and the amps simply climb .
Depending on the wiring n connectors - I can burn up a servo which is stalled . I check all servos for free travel and movement -this is a MUST
My older batteries (nimh old technology) , simply dropped voltage rapidly under load and saved the servo --also did not deliver the full torque -or even rated torque.
I recharge these every other flight -
Why?
Why not - they recharge as I refill the gas tank-
I can recharge at 8 amps -but usually use 3 amps and accept 95% / 98% full as good enough.
my 27% model takes 10-15% of 2300 ma per flight --my 33% takes 20-25% per flight - and the charger refills that in a few minutes . The A123 (3 amp charger /balancer )Cellpro - instantly tells me % of remaining charg per flight . The batts don't have to cool - just use n charge as you like.
We don't try to carry enough gasoline for a full day's flying --so why try to carry a full days battery?
The two cell pack weighs 5.5 ounces and no regulator . (thank God!)
Horizon will now be carring these A123 cells but NOT rx packs as far as I know
if you are interested in this technology - there are a number of sites now showing cells for sale --applications etc..
That's it

BaldEagel

So what you are telling us is that Hitec are selling a servo with a limited life span if used within the quoted specification? Where did you get that information?

Mike

rmh

Or is it 7.379358 v ? crap---
If you get bogged down in chasing voltage readings without knowing actual voltage AT SERVO under a given load -you are hopelessly lost.
and 30%
30% of what?
when?
how?

JEFFRO503

My Feedback: (9)

JEEZ...i disapear for 1 day and come back to check the thread out , and holy cow! I can honestly say that after reading through this thread i know a little more about servo's than i did before. Thanks for all the servo knowledge guys........keep it coming....could always use a little more.



Jeff

BTerry

My Feedback: (8)

Ask and you shall receive: [link=http://www.flyinggiants.com/forums/fg29/5743-5955-vs-5995-any-opinions.html#post72319]link to competing site enclosed...[/link]

BTerry

My Feedback: (8)

jeez. when the link pops up, type in "fly-ing gi-ants DOT com", without the dashes or spaces, to replace the "*****" that RCU parses out of the link.

BaldEagel

Sorry link does not work in any way shape or form.

Hitec spec from their catalog says designed for 7.4v why would anyone from Hitec contradict that? they are just asking for a law suite under fitness for use.

Mike