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Author Topic: Mini servo  (Read 668 times)

richardabeattie

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Mini servo
« on: October 11, 2018, 09:21:15 PM »

I'm trying to fit R/C into a 1/35 DUKW model.  (Italieri's "British Royal Army"!)  I have a Miniature Futaba 2 channel receiver.  I need a mini servo for the rudder but the internet is full of them at very low prices and often the photo does not show that there is a plug on the end of the wire.  What should I buy?
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Stavros

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Re: Mini servo
« Reply #1 on: October 11, 2018, 09:29:12 PM »

get one from component shop and ask for a futaba style plug  or pick one up at the Blackpool model show next week


Dave
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richardabeattie

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Re: Mini servo
« Reply #2 on: October 11, 2018, 09:35:38 PM »

And I now realise I need a matching micro ESC.  I am 300 miles from Blackpool.  I know little about this sort of stuff and the only shop anywhere near me is staffed by people who also don't know!  So what micro servo and micro ESC can I safely buy on line to fit my Futaba Rx?
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Stavros

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Re: Mini servo
« Reply #3 on: October 11, 2018, 09:54:28 PM »

PM sent




Dave
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richardabeattie

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Re: Mini servo
« Reply #4 on: October 11, 2018, 10:44:55 PM »

Thanks - I've asked Deans
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Allnightin

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Re: Mini servo
« Reply #5 on: October 11, 2018, 10:51:11 PM »

Can I take it that the model is only going to be used afloat - ie the ESC is only powering a motor driving the propeller?

If you can get hold a copy of May 2017 Model Boats magazine,  I did an article on using the Feetech  FS90R continuous rotation servo as a cheap way to make a combined micro power unit.  The servo is available here https://www.rapidonline.com/feetech-fs90r-360-continuous-rotation-micro-servo-37-1335

Action Electronics do the P68 micro ESC which would be a bit heavier but probably suitable and available via component shop  https://www.componentshop.co.uk/p68a-pico-1a-microcomputer-linear-acceleration-speed-controller.html

There is also meant to be a micro ESC coming from Microgyros (see other threads on this forum) but I haven't seen anything announcing it being available yet.
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barriew

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Re: Mini servo
« Reply #6 on: October 12, 2018, 07:27:00 AM »

If you can wait for something delivered from China, then this is a useful ESC for small models

https://www.banggood.com/20A-Double-Sides-Brush-ESC-For-RC-CarBoat-p-926460.html?rmmds=search


and this is a suitable micro servo

https://www.banggood.com/3_7g-Micro-Analog-Servo-GH-S37A-For-RC-Airplane-Helicopter-p-1116559.html?rmmds=search

A search of ebay may find you a similar ESC in the UK

Barrie
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malcolmfrary

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Re: Mini servo
« Reply #7 on: October 12, 2018, 09:18:50 AM »

Most servos come with a plug with the long standing standard pin spacing of 0.1".  Nowadays, the connections are in the same order, the only difference is that some makes have a bit of extra moulding in an attempt to make it more difficult to mix makes.
For ultra small, lightweight applications, there is a range of radios and matching plug-ins with different connections.  Without knowing the model number of your Futaba receiver, there is no saying whether yours has "standard" connections or not.  If you radio has its pins at 0.1" spacing, anyody's servo that doesn't mention being other than a different standard will fit.
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warspite

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Re: Mini servo
« Reply #8 on: October 12, 2018, 10:00:57 AM »

Not forgetting the also useful - convert a servo into a speed controlled motor, i.e by using only the servo this stripped down leaving only the motor the pot, the circuit board and lead, using the motor to drive the boats propeller, the circuit board as the esc, the pot to find dead centre then glue it so it does not move (though with the high tec i used, i left it fitted through the bulkhead with reels on it to reset it as seemed to ghost during trials.


is it a single prop or dual, my 1/72 LCM III tank used two props so was steered this way, so two servos one for each prop and a hitec feather receiver, the battery was concealed under a crate as the load as I couldn't find the tank.
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roycv

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Re: Mini servo
« Reply #9 on: October 12, 2018, 01:26:50 PM »

Hi I have been using and buying miniature units on-line.  I found a similar 20 amp esc at 3.80.  One of the benefits is that reverse comes on straight away, no delays. They are about the size of the last thumb joint and about 5mms thick, 
You should need to know that these small esc's have the same battery and motor connections as the ones used for batteries used for running a receiver.  The small 2 pin red ones.
However you can buy a dozen of each (wired up connectors) for peanuts.  I would not put 20 amps through them but I run at about 2 amps and no problem

I also use 9 gramme servos at about 1 each (TowerPro)  if you buy 10.  Some have plastic gears and can strip easily (mine are to work points on my model railway) there are also metal gear ones.  All servo connectors for these are standard receiver connectors, so can be used on all modern receivers.

If you need a 160 degree movement then Flytron (British, 8.50)  do a tiny servo extender, it is smaller than two receiver connectors joined together.  No controls or choices just plug between rx and servo, works nicely just check the servos can move through 180 degrees first.
Hope this helps,
Roy
 
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Allnightin

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Re: Mini servo
« Reply #10 on: October 13, 2018, 08:44:14 AM »

Not forgetting the also useful - convert a servo into a speed controlled motor, i.e by using only the servo this stripped down leaving only the motor the pot, the circuit board and lead, using the motor to drive the boats propeller, the circuit board as the esc, the pot to find dead centre then glue it so it does not move (though with the high tec i used, i left it fitted through the bulkhead with reels on it to reset it as seemed to ghost during trials.

I have used this technique in the past but there is usually an issue with finding the motor stop position because the standard servo is very sensitive to movement of the Tx control stick.  This is where the Feetech FS90R continuous rotation servo I mentioned above is much more useful because it has a substantially wider deadband than most standard servos.
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warspite

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Re: Mini servo
« Reply #11 on: October 13, 2018, 09:13:45 AM »

Granted a better option - just saying that converting servos is an option 1) if you cannot get the continuous rotation ones, 2) you have spare servos that you do not mind butchering.
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Operational vessels - 1/72 LCMIII, 1/180 Royal Soveriegn
Non Operational - 1/72 Corvette, 1/72 E-Boat, 1/72 vosper mtb
incomplete, tug, cardboard castle class, got the new job

warspite

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Re: Mini servo
« Reply #12 on: October 13, 2018, 09:17:55 AM »

The reels as mentioned are attached to the pots, so if the props start to rotate just adjusting them is to simply rotate the reels, in the side on picture just after the propeller is the motor protruding through the hull
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Operational vessels - 1/72 LCMIII, 1/180 Royal Soveriegn
Non Operational - 1/72 Corvette, 1/72 E-Boat, 1/72 vosper mtb
incomplete, tug, cardboard castle class, got the new job

Allnightin

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Re: Mini servo
« Reply #13 on: October 13, 2018, 04:50:49 PM »

Granted a better option - just saying that converting servos is an option 1) if you cannot get the continuous rotation ones

I have no interest in Rapid Electronics as  my usual source for the continuous rotation type servo beyond saying that they are UK based, have a very wide range of other useful items, are relatively cheap and have fully lived up to their name in terms of speed of response to my on-line orders.  With the demise of Maplins, perhaps a useful alternative?
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malcolmfrary

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Re: Mini servo
« Reply #14 on: October 14, 2018, 09:47:41 AM »

I have no interest in Rapid Electronics as  my usual source for the continuous rotation type servo beyond saying that they are UK based, have a very wide range of other useful items, are relatively cheap and have fully lived up to their name in terms of speed of response to my on-line orders.  With the demise of Maplins, perhaps a useful alternative?
The continuous rotation servos look like (apart from their intended use) a very good parts mine for a small control interface / motor / gearbox.  I have butchered standard servos for a long time for the motor and control, I agree that the deadband is very narrow, but this has never been a problem because I tended to use the slider rather than the stick as the speed control.  How often does a model boat really need to sit at a dead stop?  With the motor off, its going to drift anyway.
The limitations of a butchered servo are the very short motor shaft and the limt on voltage.  The Action Picos can use more suitable motors and have a more conventional stick response, but are voltage limited.  The small oriental 10A and 20A ESCs come with a built-in BEC so can use a higher voltage but the ones that I have used have an assymetric response.  When going smaller than mainstream, there is always going to be a compromise, just a question of picking the best one for the job in hand.
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warspite

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Re: Mini servo
« Reply #15 on: October 14, 2018, 10:13:22 AM »


Sorry didn't want to start an argument over the types of servo's,  <:(  but if you look at the size of the propellers in the pictures above and remember the servo's were two Hitec micro's (the blue tinted clear case ones) the attached link to a video will show how fast the boat goes, the video is not speeded up or doctored and at about 1:12 keep your eyes peeled  %) ;) , and the LCM did a hasty retreat at the end as the German U boat was being readied to leave the pond side.  :embarrassed:


https://www.youtube.com/watch?v=UgJg_S-efes
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richardabeattie

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Re: Mini servo
« Reply #16 on: October 14, 2018, 04:06:34 PM »

I'm the OP and this thread has left me far behind!  I was simply hoping to be advised which make and model of mini servo and mini ESC would plug straight into a Futaba R202GF 2 channel receiver.  I'd also need to plug a small battery pack into socket B.  I assume 6 volts would be OK.  Stripping down and rebuilding servos is above my pay grade.
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Subculture

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Re: Mini servo
« Reply #17 on: October 14, 2018, 05:35:33 PM »

Unless using miniature plugs (e.g. jst) which you won't be, all manufacturers have standardized on JR style plugs these days, which are compatible with Futaba equipment.

So one of these will do fine-

https://hobbyking.com/en_us/hxt900-micro-servo-1-6kg-0-12sec-9g.html?countrycode=GB&gclid=EAIaIQobChMI6ZOMka6G3gIVlc13Ch3XwgOcEAQYASABEgKtJPD_BwE&gclsrc=aw.ds&___store=en_us

roycv

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Re: Mini servo
« Reply #18 on: October 14, 2018, 06:22:43 PM »

Hi I can understand how threads can go just go back to thread number 9.  This answered your query. 
These days they all seem to fit. If there is any doubt with plugging into the receiver the black lead goes to the outside edge of the receiver case.

Roy
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malcolmfrary

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Re: Mini servo
« Reply #19 on: October 15, 2018, 09:47:34 AM »

I'm the OP and this thread has left me far behind!  I was simply hoping to be advised which make and model of mini servo and mini ESC would plug straight into a Futaba R202GF 2 channel receiver.  I'd also need to plug a small battery pack into socket B.  I assume 6 volts would be OK.  Stripping down and rebuilding servos is above my pay grade.
Now that the actual receiver model is known, and we now know that it has standard size connectors, what subculture said in #17 goes.
6 volts is fine as long as all of the items that you intend to plug in are OK with that.  Some ESCs are limited to a regulated 5 volts, but OK with a nominal 4.8v as from a rechargeable receiver pack.  If an ESC with a BEC is used, the receiver will get its power from the ESC, no extra battery needed, in fact the extra battery could do damage.
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