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Old Jun 27, 2005, 08:25 PM
Bertrand MICHELS
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Belgium
Joined Nov 2003
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What is the BEST MICRO servo (for a JET)

Hello all of you,

I am building a 80cm / 1 kg Electric JET (see: http://www.rcgroups.com/forums/showthread.php?t=382141 )

Now, I need to find 2 micro servos ( 10 grammes max) for this baby ! It has NO ailerons, only tailrons !

I have been told that I need DIGITAL servos for accuracy, but, in the 10 grammes range, I have found so far only the JR/Graupner DS 281.

Looking at its more carefully, I find its specs not very exciting :
- very SLOW (0,16 sec compared to 0,09 for GWS HP bb)
- No metalic gears

...my "non digital" GWS Naro HP looks better (0,09 !! almost 2 time faster)


So,

- what is the BEST and FASTEST micro servo ?
- Do I really need a digital one for accuracy (important for a Jet !! )
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Old Jun 27, 2005, 08:38 PM
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San Diego, CA, USA
Joined Mar 2001
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1) Fast means high current, which means the motor will die faster. Do you want that? Any servo is usually faster than the pilot.

2) Why do you think you need digital servos? A good analog servo is still quite good.

3) The JR/Graupner C241, C261, DS281 are all good servos. The only difference I have seen is the DS281 is slower and has less torque than the others.
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Old Jun 28, 2005, 07:41 AM
"Up Chuck-Up Chuck"
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Ft. Lauderdale, Fl.
Joined Aug 2004
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Just received 4 Dymond D60's yesterday. Lots of guys use these on their hotliners flying 100+ mph. The specs look good and they are nice and narrow (for narrow wing install.) Ive used the JR241's (slow) Cirrus (reliability issues, poor centering) BMS 371's & 306's (probably best bang for your buck, pretty good little servos) Hitec 55's & 56's (never had a problem though 56's have a MUCH stronger geartrain).

Look into Dymond. They have a little more torque than most micros. I wouldnt worry too much about the minor differences in rotational speed in some of the comparisons as you may never even notice it.
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Old Jul 01, 2005, 05:27 AM
Bertrand MICHELS
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Belgium
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hitec 56, with carbonite gears, seems good indeed.

But, Is it dast enough for a JET ? Is it digital ?
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Old Jul 01, 2005, 05:27 AM
Bertrand MICHELS
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Belgium
Joined Nov 2003
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Quote:
Originally Posted by bmaaa
hitec 56, with carbonite gears, seems good indeed.

But, Is it dast enough for a JET ? Is it digital ?

I ment FAST enough for a jet ! :-))
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Old Jul 02, 2005, 11:06 AM
FLYER spelled I-squared-R
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Grand Rapids, Michigan
Joined Sep 2001
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I think the point about speed is that even the "slow" servos are faster than the pilot can interpret and correct, so the speed will be fast enough.

HS-56 is a very good choice.
David
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Old Jul 02, 2005, 01:19 PM
sloping addict
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France
Joined Feb 2003
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I don't think there is any servo on the market that is less than 10g and with metal gears.
Also it has been measured that some Graupner (and other brand) digital servos are actually weaker than their analog counterparts and feature no specific advantages as to centering & precision.
The best seem to be Dymond D60, C261 & 271 (metal version of the same, heavier), and Hitec 56HB.
Thinnest is D60 @ 9mm.
There are all relatively slow although C271 seems a tad faster.

The slimmest metal servo I think is Futaba S3150, it is digital and *very* good although a bit slow as well, but weights already 22g. Used for larger airframes including F3B (submitted to 60G loads !!)

You should be safe with the D60, they are very precise and tough even with plastic gears and they are used in many F5B & F5D.
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Old Jul 02, 2005, 05:44 PM
Caution:Makes sharp left turns
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United States, CA, Lake Forest
Joined Feb 1999
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I stand by my JR-241s (analogue) but want to try some of the D60's when I get the chance.
Bertrand, I would not worry about the difference in speed. Worry about centering, strong gears, and reliability. I see the F-16 is using full flying stabs so you will need a strong servo with good centering. Is that the same size as the Kyosho F-16??
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Old Jul 03, 2005, 03:59 AM
Bertrand MICHELS
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Belgium
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Yes, it is same size a Kyosho, and will weight 1000 gr.
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Old Jul 05, 2005, 08:32 AM
"$$Crashable Income$$"
Tallahassee, FL
Joined Feb 2004
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i would go for a fma ps10 servo. they perform like an hs-55 but are a fair bit faster and they weigh about 2g less. im not sure it will fill the bill for torque, but i would guess they would do very well. they do make some interesting claims as to how they are 'smoother' than slightly cheaper servos. so i would guess that if there is any truth to it they are a little more precise. its something about a new chip they use or something, check them out.

im pritty sure they would be fast enough. i certanly know im faster than my hs-55's but they usualy do real well anyhow. if you want some budget speed, i would get some gws naros. and they have some decent torque. the weight is what you trade, of course, and some money too.

the plane looks sweet are you gonna paint it? a pain scheme from an airshow or a military job?
http://www.freefoto.com/preview.jsp?...uchars+Airshow
http://www.steehouwer.com/f16/f16_9.jpg
http://airshowpics.com/
this last one has a few nice pics but i cant get the direct links working right.
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Last edited by maux; Jul 05, 2005 at 09:12 AM.
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