martno1fan

nice one rick looks like we can all save a few quid or dollars now,i for one never beleived the myth lol

DaveMarles

Thats no myth and I'll tell you why and give you the results. No1 is I've tried it in several boats where rudder power is critical and it does make a significant difference. Perhaps many people wouldnt notice a difference or wouldnt need the advantage but I do.
No 2 . To get the best rudder servo performance you need to be using the correct Y lead and thats one with heavy duty wires and very short overall length of ca 70mm . The battery pack must be a good quality 5 cell welded pack nicad or NIMH. The switch assembly for least power consumption must be a heavy duty type such as the expensive Futaba one with thick wires for digital servos costs about 18 GBP part number FUTM4385. The Y lead allows the supply of a higher voltage to the servo when its under load. I did detailed torque and voltage drop tests a while ago and saw there was a major difference. I just set up a quick test a few minutes ago in my workshop and did it like this :
I put a volt meter across the red and black servo wires on my 13 kg torque KO 2174 analogue rudder servo. I plugged the servo into my Futaba 136F receiver ( correctly stated as having a bus connector across each polarity of sockets in the rx.) and plugged the switch lead into the RX. With no load the reading was 6.5 volts. I then applied the maximum load possible on the rudder and the voltage dropped to 5.7 volts. I then connected via the Y lead and applied the same load and voltage read 6.1 volts.
G.S.M.

martno1fan

theres a surprise a dealer telling us we need to buy expensive stuff only kidding ,not a lot of diff though dave was there?.4 volts so on the whole id say the y harnes isnt needed for most situations.

rickburnout666

I just got to say one thing because i dont want to start any rows or arguements i have measured the KG difference on the servos but not voltage difference , again im not an expert but have seen the results using scales

patriktegelberg

This is so fun to read. My biggest question is: what does G.S.M mean?

rickburnout666

GET SOME MODERATORS

martno1fan

i could guess but i might get moderated lol

DaveMarles

Rick... Set up as I quoted with the short Y lead/thick wiring, there is a torque difference on the servo.

Mart,
I think you said there was not a difference using a Y lead. I'm just showing that there is. To me its important, to many others probably not, especially when I look in 50 mph gas boats and see people using dry cells and not welded packs. :-)

rickburnout666

we all might be right or wrong in ways but scales dont lie, unless you`re a fat bar steward

DaveMarles

Patrik, GSM means Game Set and Match.

martno1fan

well there wasnt a dif on ricks scales with and without the y lead,voltage maybe as you say dave but the diff wasnt much in all reality.and no where near what its been clamed it would be either so i think ill stick to using the y lead for what it was designed for which is for running two servos on one channel.rick thats quite a good one ,by the way i didnt start this thread to cause a row just wanted to hear peoples views on this i know matt has run big cats without a y lead i think im right in saying if not im sure he will correct me .id say ricks test was a good one though and like he says scales cant lie dunno about electric gismos lol.

rickburnout666

Right Mart you have your answers , I think .
Dave`s the Boat expert and i`m just me . Try some testing yourself you know how to wire a Y piece and know how to use scales The choice is yours , I cant say anymore on the subject so i`m off to college tommorrow to see if i can get some help with measuring voltage and servo weight pull

rickburnout666

i forgot to mention .005 gram was without the Y piece DEUCE lol

martno1fan

id say your ahead by advantage mate thanks for doing the test, you too dave its much apreciated.one things for certain if these tests are correct the diference in using the y lead is marginal not as big a difference as some have said.i can see wher the slight difference in voltage would help in daves situation but for general sports use id say its not that important.

DaveMarles

Mart, I'm sure a lot of people would agree that every time you open your mouth you start a row but it would be boring without you on here.

I try to deal with the realities of practical tests and/or calculation and for me I don't think its good enough to say, for example, that I THINK 0.4 of a volt doesnt make much difference. I'm only interested in reality.

martno1fan

what me
[X(] dave what im saying is this ,people telling me if i use a battery in the rx ill only get 4.8 volts seems a myth ? as your tests proved,also told i wouldnt have as much torque to do the job needed ,according to ricks test also a myth!!.i dont think this has been an argument just a friendly discusion between interested partys,i hope def no offence meant to anyone.

patriktegelberg

About the BEC receivers. They supply like 4.8v to the receiver and servo. If we use a Y we will feed the receiver with 6v, yes? so the receiver can run internally on 6v as I understand it. OK no problem if it is so.

Someone I asked about this told me that the BEC circuit was only to eliminate the over voltage of fresh charged batts and that the voltage control was made resistively. He works in a hobby shop, like runs it, but that must be just massively wrong. To me the BEC must be able to handle like 12v feed and use switching to be of any real use.

Anyway such a BEC can naturally be way weak to power a high torque servo. And for those receivers Y-cables yields big gains, as only the control signal has to come from the receiver as pionted ot elsewhere. To gain power the way Dave did by lessening voltage drop in supply lines, which is not a myth, one has to go all the way as also pointed out by Dave.

Yes I run the amateur equipment in my box, not welded pack and only AAA 4.8v NiMh and thin wiring. But I think it will do.

Also the thing is that Mart is the one on this board that stresses his servo most of all.

martno1fan

pat dont start that one again lol i only hope i havent caused anyone any stress over this as i think its an interesting subject.dave has spent the time to get the results i wanted to hear and has proved there is deffinately a diff using the y harness although not as high as id been told to believe.its all been worth while i hope ?,ill be sticking with my direct setup on 6 volts to the rx though.

pete_486

well trust me im an electrician lol.
the amps through a receiver can not be anywhere near the same as a direct feed to the servo with a y lead with thicker wires, if you try a standard set up and work the throttle at the same time as the rudder there will be even less voltage and amps.
i could go into great detail but im not lol...............Pete

Flabum

Well, simply put, there is a difference between using the correct wiring and setup. As dave said, good, thick wires, heavy duty switch, heavy duty y-harness and properly assembled batteries will out perform a lesser setup. And as dave said, most of you won't benefit from the good stuff if you are not all out racing. If what you have "will do" then that is enough for you. When it comes to serious racers and people like me who spare no expense in what we do, then it makes a huge difference.

Mart, you are right that it is not needed in all applications like your 35mph boat, but for those running 50+ it is foolish not to spend a few dollars more and do it right.

pete_486

yes i agree flabum, i have no need for that set up yet my boat does between 45-50 maybe, and my servo takes it.
i understand all aspects of direct wiring and will do it when need be............PETE

patriktegelberg

I am crowning this thread, most satisfying read here. Interesting subject and many people involved, some who presented actual test results. It lacks a bit in pictures but good fun. Thanks, more like this. Create a stir and get in there. To wish for could maybe be more explainations of reasoning behind opinions.

martno1fan

glad ive entertained you pat lol ,ive also learnt a lot from this too which is why ive kept asking and sometimes annoying the heck out of some of you guys not becauase i wanted to be argumentative (moi?) but because i wanted some real answers and now i have them thanks guys much apreciated .sometimes its all too easy just to take the first answer you get as been correct and its not allways the best idea so thanks for all the answers and test results guys i hope this thread is usefull to others too.

MrMikeG

Funny how all the guys that really run boats agree on the Y harness and only the new guys with ONE boat are trying to prove it wrong! Trust the guys that have been there done that with fast boats.
To me the only thing proven here is slow boats don't need a Y harness, heck as I said before they don't even need a high torque servo so you all can save yourself heaps of money, but if you want to go fast then you will gain more control from the Y lead and High torque servos.
If it is a money thing just solder your own switch into the Y harness, save heaps! Y harness $6, water proof switch $3, knowing I have the best = priceless [8D]

John Howell

Mike, you know the saying - You can lead a horse to water.......