Maurice Harvey Posted August 20, 2012 Share Posted August 20, 2012 When is some enterprising servo manufacturer going to throw away the mould and give us, (I mean sell) a servo that is:- Universal, for wing or fuse fitting. Worm and quadrant drive that will eliminate "blow back". Interchangable gearing, (for torque or speed). A genuine 10v input, (instead of this 7.4v, 2 lipo sales blurb. My volt meter shows 2 lipos as 8.4v. If we had such a servo you would be able to buy what they offering us now at two for a pound on any street corner! Quote Link to comment Share on other sites More sharing options...
Alan Cantwell Posted August 20, 2012 Share Posted August 20, 2012 AND WIRELESS, i hate sorting servo wires, wonder if it would be possible to employ a router?? Quote Link to comment Share on other sites More sharing options...
Bob Cotsford Posted August 20, 2012 Share Posted August 20, 2012 I'm not so sure... Eliminate blowback - the problem with the worm drive is that bumping a surface wil break something rather than moving the servo and if the servo is sized for the job then blowback will not occur, at least for the vast majority of regular size models. Variable gearing and 'universal mount' - I take it you are not thinking of servos for use in the average sports model here? Quote Link to comment Share on other sites More sharing options...
Vecchio Austriaco Posted August 20, 2012 Share Posted August 20, 2012 Actually I have several planes which are using only one type of servo in the whole plane - for instance: Seagull Extra 300 60 size - all Spektrum DS821 except trottle - which is smaller Sebart Angel 50 - all Spektrum DS 821 E-flite Extra 300 -30 - all Hitec HS 225MG If you have super fast, super big models than you have to invest also into super expensive servos. For the every day plane I don't see any problem. VA Quote Link to comment Share on other sites More sharing options...
Maurice Harvey Posted August 21, 2012 Author Share Posted August 21, 2012 Bob, The advantage of the worm and quadrant is the aerodynamic loading on the control surfaces is not transferred back to the servo. This relieves loading on the gear train, the servo motor is not having to be supplied with amps to hold the c/surface allowing more power to go to the servos that you want to move. In my experience, if you are feeding power through a regulator what you are told you will get as regards amps you should halve it. Crow braking will show the lack of power, or telemetry. As for the control surfaces not moving when we knock them, we must treat aircraft with respect when we handle them. Quote Link to comment Share on other sites More sharing options...
Bob Cotsford Posted August 21, 2012 Share Posted August 21, 2012 Posted by Maurice Harvey on 21/08/2012 11:53:20: As for the control surfaces not moving when we knock them, we must treat aircraft with respect when we handle them. nice theory. Doesn't always work in practise though Quote Link to comment Share on other sites More sharing options...
Jonnor Posted August 21, 2012 Share Posted August 21, 2012 Servo drive apart, I've been wishing for years that all servo manufactuyrers would give us a choice of cases for each and every servo.......securing shoulders at the top, for conventional installation needs and shoulders at the side so they can be fixed flat in a wing for aileron use. That's not asking for the world is it? And either type should be the same price rather than paying oodles more for a "special" aileron servo. But not one manufacturer is interested. Quote Link to comment Share on other sites More sharing options...
Maurice Harvey Posted August 21, 2012 Author Share Posted August 21, 2012 Hi Bob, I give up. Whenever I try to get people thinking of something better or different the negative always rises to the surface. Back to the cave eh. Quote Link to comment Share on other sites More sharing options...
Mark Powell 2 Posted August 21, 2012 Share Posted August 21, 2012 Maurice, Don't worry about the 8.4 voilts. The onload voltage of two lipos is 7.2 to 7.4 volts and that is fine for all the 'two lipo 'servos. Your 8.4 volts is offload. What I would REALLY like to see is the option of the old 'linear servos' of a good few years ago. The opput was two racks iinside with an upright servo arm out of the top. They truly moved in a linear fashion, backwards and forwards, just like the pushrod you attach them to. A rotary servo output goes sideways as well as backwards and forwards, so cannot be linear..Every 'good and expensive' heli you see claims that its wonderful CCPM setup avoids interaction between the controls.In fact this is totally impossible with rotary output servos. With linear servos there will be no interaction at all. There were dozens of them, Some had the option of rotary or linear. Bring them back!!! Quote Link to comment Share on other sites More sharing options...
Maurice Harvey Posted August 21, 2012 Author Share Posted August 21, 2012 Mark, Thanks for the info on 2s lipos. Where I have 7.4v servos I will remove the regulator and keep my fingers crossed! As for the old linear servos, yes, lets have an updated version. You know, if I were a servo manufacturer I would be looking to make a product that has "saleability" in its spec, not just something that every Tom, Dick or Hitec makes. Quote Link to comment Share on other sites More sharing options...
Mark Powell 2 Posted August 21, 2012 Share Posted August 21, 2012 Alan, Wireless? You still need a power lead, which is two wires, so you had just as well put the signal lead in too, which is how they are now. Futaba S-bus? Better, a few less wires, but not many. It is techincally not new at all. All they have done is add a 'shift register' to the servo, or the S-bus adapters for old servos, led the single output wire from the receiver proper to the input of the existing shift register already in the receiver case to a socket as well, to which you plug the S-bus system. The Futaba S-bus system and servos works fine with most Multplex systems too, as they have done a similar thing in their receivers, but have not made any fuss about ut. On a multi-servo wing, ailerons, flaps, electic u/c you can presently end up with six leads. You can simplify this by stringing all the power and ground leads between the servos. Quote Link to comment Share on other sites More sharing options...
John Muir Posted August 21, 2012 Share Posted August 21, 2012 I'd just like to see a servo with the lead routed out of the case above the mounting lugs, or even better, without a lead at all - sockets for click locking plugs built in instead. Then servo leads could be removable at the servo end making the servos easier to get out for servicing and we could avoid having joins in servo extensions hidden away in places you can't get at them. Surely that wouldn't be too hard to do? Quote Link to comment Share on other sites More sharing options...
Mark Powell 2 Posted August 21, 2012 Share Posted August 21, 2012 John, Sorry to bang on about MPX. Their servos up to about 18 months ago all had the leads coming out of the top. Their truly excellent 'wing servos' had click-in leads just like you suggest. Plus the output arm fully supported on both sides, not stuck out of the end of the case. Then they got taken over by HiTec. Now their servos are just HiTec ones in traditional MPX red cases so all that good design has gone. I don't really 'bang on' about MPX. I didn't buy it then try to justify it afterwards. I boughtb it because I thought it was good, it had 'justified itself to me' before I bought it. If I had not liked it I would have bought something else. Edited By Mark Powell 2 on 21/08/2012 15:51:59 Quote Link to comment Share on other sites More sharing options...
John Muir Posted August 21, 2012 Share Posted August 21, 2012 Mark, there was me thinking I was being an original thinker! I didn't know about the MPX ones, but it's such a shame that sensible design features like that are chucked out presumably in the name 'standardisation' or more likely, cost cutting. Or probably some guy in marketing said 'there's just no demand for that sort of thing' based on a customer clinic conducted down the pub, and that was that. Quote Link to comment Share on other sites More sharing options...
Allan Bennett Posted August 21, 2012 Share Posted August 21, 2012 Posted by Mark Powell 2 on 21/08/2012 14:58:57: ... What I would REALLY like to see is the option of the old 'linear servos' of a good few years ago. The opput was two racks iinside with an upright servo arm out of the top. They truly moved in a linear fashion, backwards and forwards, just like the pushrod you attach them to. A rotary servo output goes sideways as well as backwards and forwards, so cannot be linear..Every 'good and expensive' heli you see claims that its wonderful CCPM setup avoids interaction between the controls.In fact this is totally impossible with rotary output servos. With linear servos there will be no interaction at all. There were dozens of them, Some had the option of rotary or linear. Bring them back!!! But, if you use linear servos you need to make your control horns linear too, don't you? I can't think of any on my models that are linear Quote Link to comment Share on other sites More sharing options...
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