Tosh McCaber Posted March 24 Share Posted March 24 I'm looking for a couple of wing servos for my 48" Aeromaster, which I'm renovating. I've come across ads for JX PDI-2105MG 21g High Torque Digital Slim Servo, which describes the operating voltage as being 6~7.4 V. Now my understanding (which may be wrong!) is that, with the BEC on the 6S LiPos, the output Rx/ servo voltage output is 4.8V. My question- is this servo suitable? If it runs at a lower voltage, it's torque output (6.8 kg.cm @ 6v- 7.9 kg.cm @ 7.4v) would obviously be lower? Will this give problems? Altrnatively, has anyone recommendations/ illustrations as to how to fit standard servos in each wing? Thanks for any answers from those who know! Quote Link to comment Share on other sites More sharing options...
Dickw Posted March 24 Share Posted March 24 Most of the adverts I can find for that servo give a voltage range of 4.8 - 6v. One said 4.8 - 7.4v. Most HV servos work OK on a 5v supply, but with lower torque as you say. I don’t think the Aeromaster needs high torque, so at that price its worth a try. Dick 1 Quote Link to comment Share on other sites More sharing options...
Tosh McCaber Posted March 24 Author Share Posted March 24 Thanks for thatDick! As well, has anyone recommendations/ illustrations as to how to fit standard servos in each wing? Brackets, or? Quote Link to comment Share on other sites More sharing options...
kc Posted March 24 Share Posted March 24 (edited) If you want to fit them 'flat' then these servo mounts from SLEC might suit. I think they are the same as Radio Active ones. Instead of mounts some people just wrap the servo in several layers of masking tape and epoxy the tape onto wing, cutting the tape apart if servo neeeds removing. Edited March 24 by kc Quote Link to comment Share on other sites More sharing options...
Tosh McCaber Posted March 25 Author Share Posted March 25 Thanks for that- looks like a good way to go! Quote Link to comment Share on other sites More sharing options...
Nigel R Posted March 25 Share Posted March 25 18 hours ago, Tosh McCaber said: Thanks for thatDick! As well, has anyone recommendations/ illustrations as to how to fit standard servos in each wing? Brackets, or? Make some hatches in the wing from thin ply, fix some wood blocks to the hatch, mount servo to the blocks. Or some pre-rolled: https://www.elitemodelsonline.co.uk/More/Radio-Equipment/Radio-Accessories/Servo-Mounts/40994-/Micro-Wing-Servo-Mount-2pcs?fo_c=3984&fo_k=582ee6f617e198858da484827152f322&fo_s=gsuruk&srsltid=AfmBOopx3hG4j84BGbo3vgVmwtsCecIvy_U7Z-MjinW5ZodtKAdJm3Adx6E Lots of ways to skin the cat. Or, just fit the upright and let the servo arm stick out into the breeze, this is usually the quickest way. Quote Link to comment Share on other sites More sharing options...
Martin McIntosh Posted March 26 Share Posted March 26 I have a Super Aeromaster and use 4 Corona DMG aileron servos, simple to fit but I did once get a couple of duff ones out of the many in use. If you are prepared to spend a little more on, say, metal cased ones then you would do well to go down that route. Quote Link to comment Share on other sites More sharing options...
Graham Davies 3 Posted March 26 Share Posted March 26 On 25/03/2024 at 11:15, Nigel R said: Or, just fit the upright and let the servo arm stick out into the breeze, this is usually the quickest way. One thing to note if you do this; the axes of the servo and aileron are not parallel. This means that you ideally need ball joints at each end of the pushrod. If not, and you have no slop (there's usually a little), then the servo will stall to a degree as it tries to twist the pushrods in their respective holes. If you put the servo on it's side so the axis of the servo is parallel to the hinge line, this problem goes away and makes pushrods simpler (you can use z-bends or clevises, or both!). That would be my bet; make a frame in the wing, make a hatch cover to fit in the frame, and then wrap the servo in tape and glue it to the hatch cover. Screw the hatch cover to the frame. Simple, quick, effective. Graham Quote Link to comment Share on other sites More sharing options...
Martin McIntosh Posted March 26 Share Posted March 26 I have not used clevises for many years now, just mini ball links to get round that problem amongst others such as overly tight fits. The Aeromaster wings are quite thin so standard servos would protrude a fair bit. Very much simpler to fit thin wing ones, a simple mount with three screws. No need to add weight by fitting covers. Taped and glued may be OK on foamies but that thing is going to be quick and heavy so that is a no no. Quote Link to comment Share on other sites More sharing options...
Dickw Posted March 26 Share Posted March 26 29 minutes ago, Martin McIntosh said: .............. Taped and glued may be OK on foamies but that thing is going to be quick and heavy so that is a no no. Actually, taped and glued is quite common on some high performance gliders - 1.6kg and 150mph+ BUT you have to do it properly, and that would preferably be glued to both wing skins. Dick Quote Link to comment Share on other sites More sharing options...
Tosh McCaber Posted March 29 Author Share Posted March 29 Another query- In case of future maintenance requiring the removal of a wing servo, I don't want the complications to extend the aileron servo wiring through the wing. Rather, I'll keep the servo wiring within the servo bay, and use a non-removable extension cable with plug and socket built into the wing. This will join to a cable attached to the Rx. So we have three plug/socket joints- 1) at the servo, 2) at the receiver, and 3) the socket connection between wing and Rx wiring. My question- are these intermediate joints going to cause a continuity problem? Or are the socket connections pretty solid? Quote Link to comment Share on other sites More sharing options...
Tosh McCaber Posted March 30 Author Share Posted March 30 19 hours ago, Tosh McCaber said: Another query- In case of future maintenance requiring the removal of a wing servo, I don't want the complications to extend the aileron servo wiring through the wing. Rather, I'll keep the servo wiring within the servo bay, and use a non-removable extension cable with plug and socket built into the wing. This will join to a cable attached to the Rx. So we have three plug/socket joints- 1) at the servo, 2) at the receiver, and 3) the socket connection between wing and Rx wiring. My question- are these intermediate joints going to cause a continuity problem? Or are the socket connections pretty solid? Just wondered- does anyone have any thoughts on my query? Quote Link to comment Share on other sites More sharing options...
John Lee Posted March 30 Share Posted March 30 Not a problem if you use good quality connectors and it is standard practice over extended runs. If I go down that route (rather than my preferred method of removing a plug & socket & soldering the joint) I always use a secondary method to secure the servo lead to the extension, heat shrink tubing, one of the commercial clips &/or extension leads that have a securing tang. Quote Link to comment Share on other sites More sharing options...
Martin McIntosh Posted March 30 Share Posted March 30 Depending on how long the servo leads are that could end up with very long wiring unnecessarily and reduce the voltage so not a great idea. If the ribs are deep enough then just make large holes in them, tie a small weight to some thread and rattle it through for a draw cord. If the ribs are shallow then simply remove the plug shell from the wires then pull them through. A `dog leg` round wheel wells may require pre wiring. Quote Link to comment Share on other sites More sharing options...
Martin McIntosh Posted March 30 Share Posted March 30 No soldering involved. The shells can have the crimped connectors pushed back in. Quote Link to comment Share on other sites More sharing options...
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