nuvaring

My Feedback: (6)

Just getting into my first 100+ inch giant scale bird, QQ 102 Yak... ordered it, can't wait to get it....

I guess what I need help on is understanding the electronics now that I need 2 servos per aileron and 2 for the rudder. Trying to follow some other threads but I'm getting a little confused.

Match box vs Power box, etc....

Do I need multipe batteries for the receiver? In the past I've used one big ass nicad for receiver and one for ignition. For servos I'm looking at either JR 8611's or Hitech 5955's.

Looking for input.

Thanks

SBerkheimer

You are going to get lots of different opinions on how to set this up. I guess I will jump in here and give you mine. I will try my beat to explain things as I go along


Servos, I would use the Hitec 5955s because they are programmable and the gears wear better. With multiple servos on a flight surface it is important for the servos to be in sync. This can be done with a device such as a match box but with this airplane you would need them on each aileron and the rudder. The cost of these devices is around 50.00 while the Hitec programmer is about 140.00 so there really is no cost difference here.

Smarf Fly power expander will make sure you get enough power to the servos. Each servo will be driven by its own slot in the expander. With matchboxes 2 servos plug into one unit and the end result is 2 servo being driven through 1 connector. 5955 and 8611 alike need good power to get to full potential.

Fromeco adjustable regulators, Badger switches and Li-ion batteries. Super quality batteries. Run 2 2400mah batteries and regulators set a 6V into the Power expander. This will be enough power for 6 flights with enough left over for safety. Run the same 2400 and reg set to 5.5V for the ignition.

Shawn

Hooked-On-RC

My Feedback: (16)

Personally I would avoid programmable servos unless you know 100% how to use them and have a VERY VERY good working knowledge of the programmer itslef. Use the KISS method for your first large scale plane and you will be far better off. Match boxes work great and are VERY easy to work with, sometime you can even set up the servos perfectly with the linkages and do not require either a programmer or a matchbox, but that takes a lot of practice.

As for Power Expanders etc they are great to work with and some of them now even feature something similar to a matchbox for servo matching built right into them. I can only speak of my knowledge and I have used the EMCOTEC system from Desert Aircraft and I love it. It has built in voltage regulation and will switch out 4 different voltage levels to the servos based on a your preference, if I remember correctly they are 4.8V, 5.1V, 5.5V and 6.0V. I asked a HITEC rep once how much of difference in torque would one notice between 5.5V and 6.0V and he suggested it would be negligible so I run my system at 5.5V and the batteries seem to last longer between charges. I run two Fromeco 4800 Mah Lithion for my servos and one 2400 Mah Lithion for my ignition. I run 11 JR servos in my big bird, 9 of them 8611's. The emcotec system also features these really neat, fool proof pin switches which work great and have a very bright red LED on them to tell you if your plane is turned on or off.

As far as gear wear is concerned that can be misleading too. Gear wear is a function of many factors mostly mechanical advantage and how hard a servo has to work to perform the job. This determines the amount ot stress put on the gear set and how well they wear. I dont think any one servo is any better than any of the others regardless of gear material or servo torque, a servo will wear faster if it is set up incorrectly. Horizon Hobby has some great "first timer" tips and advise on their website, you also have this website which contains a wealth of knowledge, but trust me you will get inundated with a WIDE variety of answers and opinions, especially as a newbie. Over the years I have gotten to know some of the regulars on this site and have come to trust their opinions as their experience and knowledge is neither biased nor opinionated. One such fellow is a gent by the name of Silver Surfer, I find his advise awesome as well as very informative. Anything electrical, talk to Michael Glavin, he is an expert in that area, although he is slanted towards Hitec..I wont hold that against him, I just wont use the product.

So good luck in your setup and do yourself one favor, realize it is not a matter of IF you are going to crash your plane, it is just a matter of WHEN....when you realize that, as you watch your $4-5000 plane tumble helplessly to the ground, you won't feel so bad bringing it home in those plastic body bags!

gadix

My Feedback: (2)

1. hitech 5645 for ALIE are enogh while u use a 6V batt - u'll get 13Kg
2. 2*5645 for ELEV are enogh as well
3. 1 for RUDD 5955-> 20Kg
4. for TH a prefere a digital one, couls be a micro servo so u can install it as close to the engine.

why to pay more,JR, and get less pwr???? with the hitech u get more PWR for less money

in this size a 100cc it is better to get a PWR box or SMART FLY batt splitter and to use a 2 batt system, for safety and servo PWR.

u can get 2-3 match boxes by JR and set'em up will take a while to get an accurate throgh and movment.

try to get a much as u can information at RCU and from exprienced personal,
this way you will get the best resaults.

enjoy

fancman

My Feedback: (16)

Go here and watch the tutorial video of how to set up multiple servo's and use the Hitec programmer. Very informative.

http://www.downonthedeck.com/videos_instruction.htm

blikseme300

My Feedback: (118)

All the previous options will work. What has not been addressed is that for best results, no matter what devices are used, is that the mechanical installation of the horns and linkages is very important.

I personally don't use any electronic devices or programmers when I have 2 or more servos on a single surface. There are 2 main steps in getting this done.

Firstly, the linkage itself. The geometry of the horns to the control surface. The height of the linkage attachment point from the hinge center and the angle of this point. On a typical GS aerobat the aileron tapers to the tip. Using a horn that cannot be height adjusted is bad. I use the Rocket City style horns. This allows fine vertical adjustment. Set the heights to be the same from the hinge centers. The attachment holes for these horns need to be parallel and ideally will be 90* to the cord line of the surface as well as exactly over the hinge center. This last point will eliminate mechanical differential. Not critical, but good. If the hole are not pre-drilled, do them in a drill press to ensure that they will be vertical and parallel.

Secondly, match your servos. (I am a capitalist pig, according to my wife.) I always purchase more servos than I need for a project. I will connect multiple servos to a RX channel and power them up. Then I fit each servo with a horn that will be used for the surface. I match a pair for each half by selecting the ones that have the horns the same. This pair is then mounted in the wing and the control links are fitted. These are adjusted so that the current draw on each servo is the same throughout the full deflection. I use inline current testers for this. You can make your own or purchase from Horizon. Once set up I simply use a heavy duty wye lead for each wing panel.

For power I use 2 5-cell NiCads, 2 switches into one RX.

I have used these methods on all my GS planes and after hundreds of flights still work like a charm. I believe in KISS.

I have seen too many GS planes with all the fancy doo-dads that fly badly because the basic mechanical setups were done badly. Don't expect that you can adjust out bad setups using a high-end TX or adjuster devices.

As usual, this is all my opinion, you are welcome to your own.

Safe Flying!

Carroll-RCU

My Feedback: (43)

This is my setup on my 33% AM Yak
One receiver PCM JR649
Hitec 5945 on ail. two per wing.
Hitec 5945 on elevators.
JR DS811 on throttle
Hitec 5955 w/4" offset servo arm on rudder (pull-pull setup)
Three JR heavy duty switches (two for receiver and one for Ignition)
Three 2400 Fromeco batteries with 6V. regulators (two for receiver and one for ign.)
Heavy Duty extensions
Note: The Hitec 5945 servos have been replaced with the 5985
Keep it simple and find someone with lots of big bird setup experience to help you.
I don't have match boxes or power expanders. These items are not needed IMO for this setup unless you just like to spend extra money.
Carroll

JoeAirPort

My Feedback: (41)

All the electronic gizmos are great but here is the most important part of the process for ganged servos:

Part 1) Match the linkages by adjusting the pushrod lengths and control horn heights. This is done with no power on the servos and by using little paper protractors on the servos and surface. They have to be as dead nuts perfect as you can.

Part 2) Program the Hitec servos or use a Matchbox/Equalizer to set centers and endpoints. Use a current meter to fine tune.

This will solve many problems: Failed servos from fighting each other, drained battery resulting in a crash from fighting servos, drained batteries causing shorter flights from fighting servos, and premature gear wear from fighting servos. And you will also get smoother surface operation. There are videos that cover this process but it took me some time to master it, Well worth the effort. My battery charge lasts forever. I never have servo problems (I bet many of those servo failures are not the mfg fault).

Always go overboard on the torque. It never hurts, just costs more.

nuvaring

My Feedback: (6)

Thanks guys, all good info. just need to absorb it and bring it all together. Looks like I will have the QQ Yak next Tuesday.... Already ordered the DA100, headers and cans.

pizza

My Feedback: (24)

I never gang servos because servos move at diff rates under load. doesn't matter how good you are with linkage/setup etc. servos can lineup at every deflective angle but due to diff resistence in wires, internal resistence in servos, lag between channels, etc they never move in sink which wreks gear trains and motors, zaps power, in an extreme case servo can stall/short shutting down a lipo/lion batt in seconds causing a crash. I just shake my head when I see pilots constantly adjusting ganged servos. it is no longer necessary with new high torque servos on market, 2 and 3 float style rudder servo trays. on my 40% plane I split the ailerons in half - this works great no ganged aileron servos and no constant adjusting. on my 40% extra with split ailerons I was very careful to match linkage (because outboard aileron is more narrow at leading edge than inboard it requires a diff length horn) I used same length/gauge wire to both servos with a y harness without amplifier. I was able to get both ailerons to rest together at any stick angle but when I move the aileron stick back and forth fast I can see up to 1/4" gap between them - ouch. I was able to reduce this mismatch some by selecting 2 8611a servos from 12.

SBerkheimer

I would bet that the servo mis match during sweep is being caused by the Y connector. Digital servos do not like being operated on a feedback loop that a Y creates. If I am not mistaken IMAC will not allow split ailerons as they consider this an added flight control that the full size aircraft does not have.

Shawn

pizza

My Feedback: (24)

I have observed this mismatch using separate channels and no y harness also. when you show up for imac contest put a piece of scotch tape accross the gap joining the two halves but leave some slack - they will have to allow it and you will get all your flights on one charge. airplanes with ganged servos get up to 40% less batt performance.

SBerkheimer

I guess that would be up to the descretion of the CD. I am a CD and would allow it but I'm not so sure all CDs would.

On my 40% Comp ARF 260 I use 2 servos per aileron, 3 rudder and 2 per elevator. The ailerons and rudder use SF Equalizers while the elevators have 5955s that are programmed. I can get 8 flights and under a 1.5 amp load my batts read 7.3V typically. The RX batts are dual Fromeco 4800 relions. I do have a tough time beleiving a 40% higher draw with ganged servos. Im am sure that it is higher than your setup but how on earth did you come up with that figure.


Shawn

Tired Old Man

My Feedback: (1)

I'd like to hear he 40% less explanation as well. As one that regularly gangs servos, machtes linkages, uses Matchboxes, etc., I have yet to experience this massively increased electrical load. I can see where someone may introduce problems via an improper installation and adjustments, causing a severe battery drain, but the owner would hear the set up screaming at him and would easily recognise that there was a problem.

As for the split aileron and using tape to qualify it as a single unit....unethical at the very least. If the full scale was not built with a split, then the model should not have one either.

Hooked-On-RC

My Feedback: (16)

40% Less Battery performance....that is a pile of Hooey. Only if the ganged servos are working AGAINST one another. If your linkages are setup correctly and the servos are matched using whatever means, there should be NO more extra current draw than if you were using an extra servo. A servo fighting to do what it is intended to do will increase current draw and decrease battery performance significantly, but not if they are set up correctly. Silver Surfer is right explain that one to all of us please mr. Pizza

Mrs R

what gets me is in a 40% model we can use 12 to 14 digital servos on the control surfaces, with each costing from $150 to $300 each and they can't even get the servos to centre at 90% to the side of the case. (my pref.)

JOHNS3D

My Feedback: (5)

what radio are you using?

sherman89

As post #2 says you will get a lot of opinions on your question. For 35% aerobatic planes I use a pair of A123 paks unregulated fed into a Smart-fly power expander through the Fromeco wolverine switch, this gives me full power to all servos and allows up to 3 servos per channel ( I use 2 7955's servos per aileron, 1 7955 per elevator and 1 7950 on a push/pull per rudder) and a regulated 5.5 vts to the rx. When setting up the wing I set all sub trims at 0 and plug both wing servos into the chosen channel group. I program all servos to the same center and left and right points using the Hitec programmer and then I set the arms up to be 90deg to the path of travel. I then chose the inside servo and unplug the outside servo. With the inside servo powered up I center the aileron by mechanical means to keep the servo arm at 90 deg when centered and making sure the horns have been properly set for equal travel, when I am happy with the center and movement I then plug in the 2nd servo with a current meter plugged in line and align the aileron using the mechanical link to reduce the current draw down to zero. When properly set the servos will not cry which means they are fighting each other and will increase the draw on the paks, if the fight is bad enough you will burn up the servos. I have used this same method on several thousand flights on 35%er's as well as 40-43%er's. The trick here is to find what works for you and keep it as simple as possible (KISS). The only thing I change going to the 40-43%er's is changing out the 7955's for 7950's everywhere and adding the 2nd 7950 to the push/pull. The second servo on the push/pull is set up the same way. I have used this method over the last couple of years without any problems. This the same setup in my $8,000. IMAC planes.