Hello everyone,
This is pretty random,but I was wondering what you guys feel is servo pecking order?...
For example,say I need (4) servos for a standard "all around" plane,as in one for aileron,elevator,rudder,and throttle....
Now say none of the (4) servos are equall in torque,only equall in speed...servo#1 being the strongest,and servo#4 being the weakest...
How would you guys prioritise which servo drives what???
Im figureing throttle will get the lowest torque setup,so thats already answered,but how about the other three...

After you have an opinion about that question,this time figure in that the aileron channel can have two seperate servos,one each driving its own aileron... How would you order the power priority with this set-up... What Im getting at,is I have this problem with a plane Im putting together...
Each of my servos,meet the minumum torque requirements,but each has different torque rating,and I have to buy a servo to match one of the 4 I have now,since the plane requires two aileron servos... Now,which should I match and buy to make the aileron pair... Should I buy another one of the weaker ones I already have since there will be two,or do you guys recomend matching a stronger servo on the Ailerons... Any help would be much appreciated.... Josh L.

The most powerful servo should go on the rudder as this is usually the biggest control surface and it's always by far, the most powerful control surface,

Next would be the elevators, then the ailerons but that's hard because both are pretty equal. Now the key is if you have a seperate servo for each elevator it is important that they are equal in speed and torque. Same goes for the ailerons. If you are running two servos, one each for the ailerons they must also match.

Otherwise in relation to the elevators you will have one moving faster then the other and the plane will snap/roll to the side with the faster one. In the case of the ailerons, if one isde is faster/stronger the plane will roll faster to that side plus your rolls will not be axial and will look more like a barrel roll

Cool...Thats what I was looking for... I guess I'll just put that high MG-torquer on the rudder,and the others else where... I was thinking about putting a micro in there for the throttle,but Im not sure yet... Would make more sence though...Weight and energy wise,it should save a little...
Anything I should know about putting a micro in?... I mean will they should hold up to constant use on a large scale glow powered plane,right? I know they shouldnt have any problems as far as torque gos...
I mean who needs it on a throttle/carb link anyhow??? Thanks for the help... Josh L.

Bubba did good and those are 3D and pattern plane for sure. There are exceptions , like , if you have the room for a std size throttle servo use it. Because some throttle cables snaking around tanks, bulk heads, and firewalls bind alittle and could use the extra torque. Not to mention Perry carbs have a bit more throttle arm resistence. The other exception would be if you have a large plane with only one aleron servo and in wing cableing the strongest would be best. I just did the Joss stick 108 and decided to stay with one servo setup. Big wing with full length flaps. I put a 60OZ instead of the 44OZ. Keep in mind most small servos have only 2 screws holding them in an not all plane servo mounts are thick and strong.

I got ya... But if I do run a micro servo,Im not going to run it in the stock location... I plan to mount it directly on the fire wall,and link the servo arm to the throttle arm with a heli ball link setup... So there shouldnt be any flex or slop what so ever.... Who knows,Im just talking circles while I impatiently wait on the plane to arive at my door step! Any of you been there?!!! Haha.. Bye-4-now Josh

Josh,

What plane are we talking about here?

The Great Planes P-6E Hawk is what Im setting up now... Even though all my servos are above the "Great Planes" recomended torque rating,I'll prolly never fly the thing past 3 quarter throttle,not really needing as much torque as GP requires anyhow....
I really just wanted to know for a good reference...
Im building a 3-D machine some time soon,and I was wondering which applications needed the higher torque values for a bird thats gonna pull high G's,and need that extra snap to the control surface's,ect...
I figured it would be wise to ask here in the 3-D forum,since you guys are like a servo boot camp,testing your equiptment to the limits,knowing what works and what doesnt...
Anyhow,thanks for the help... Josh

The problem some folks have with micros on the throttle is usually not from a lack of torque, but from being fragile. Some of the micros do not tolerate vibration well.

Well Bubba... I would have to disagree with you entirely. In my opinion...your most powerful servo...and the one you least want to strip...is the Elevator. You can land a plane with a loss of an aileron, rudder, or throttle servo. You would be hard pressed to land with a failure on an Elevator servo. With today's 3D planes the Elevator is close in surface area to the rudder....and most ailerons are HUGE...the largest surfaces by far (see Funtana .40)

The first gears that got stripped in my Funtana were the aileron servos (standard JR 537's). I replaced the ailerons and elevator with JR Sport 125 MG (125 oz torque with metal gears). The rudder still has a standard servo and has no problem after a lot of abuse (I would have put a new servo on the rudder but lost the servo screw ...its a fine thread and they have been out-of-stock for months).

IMHO...Elevator...Safety first.

Maybe I should have been a little more clear. Metal gear servos are always the best choice and I will never argue that point, but let me ask you this.

Why is it that almost every large plane has the most servos on the rudder and almost every manufacturer always recommends the highest torque servos be on the rudder?

I for one believe in overkill when it comes to torque. I will always use more servo than is required and always metal gear. A good example is the GP ultimate. That's a huge rudder, the minumum required is 130 ounce but I have 250 ounces

My point is all surfaces are equally important.

Bubba, my point is that they are not equally important. The Elevator is by far the most important servo to keep from failing...you can fly all day without ever touching the rudder stick. Try flying a lap without the rudder...you even need it in Knife-Edge.

Now I do agree with you that many large scale 3D aircraft have 3 servos on the rudder and maybe 2 for the elevator. But with the question that we were given...I choose to put the strongest servo on the elevator.

I did not say you were wrong ....I just chose to disagree.

And if I implied that you were wrong that was not my intent and apology to you

What I'm saying is I use a good bit of rudder in way I fly. (KE loops both big and small, high Angle of Attack KE both nice and slow and low to the ground up to a several feet above the ground and zipping right along, snaps and such) In KE flight the rudder IS the elevator and the elevators become the rudder but with a lot less load. I was taught the proper use of rudder in my full scale career and I carried that into R/C and it has served me well from certain disaster with student planes

Also, the rudder can most definitely save you from diaster in the case of an aileron servo failure and even help out in case of a split elevator failure as long as the rudder is powerful enough.

This applies to almost all planes 40 size and up. You will notice that trainers have small rudders because it's unusual for a fairly new pilot to even think about the rudder, but when you move up to more aerobatic types you see the rudder is larger in almost all cases, including your Funtana both the 40 and 90 size

The way I see this it is this

We both agree that metal gear is the way to go
We both agree that good strong servos are needed for the elevators
We agree that the elevators and ailerons are important for directional control

We disagree that the rudder is also an important control surface

So lets leave it at that and I would like to here what others think of this. This is all good and I'm enjoying this debate very much

Elevator servo has to be the Most important servo that any plane has. You can land without Throttle, Rudder, and you need at least one aileron. But if you do not have a Elevator servo you can kiss your plane good bye!

However I still think that the Rudder needs the most torque.
Elevators need the next largest amount of torque.
Ailerons
and then Throttle.

Hey Bill (Bubba)

You make your point very well...and I dont have a problem with anything you are saying. Would you agree that the most torque should go on the control surface with the largest area? My Funtana's ailerons are at least twice as large as my rudder.

Is Elizabethtown near Hershey?? I used to make that long drive from Elmira to Hershey/Harrisburg at least a dozen times a year.

Yep. I'm 3 miles from Hershey Park as the crow flies. I'm also surrounded by 3 chocolate factories. Hershey, Reeses, and M&M Mars plus Strohman bread

And everyone wonders why I'm overweight. I smell chocolate in the air allot and the occasional warm bread which I espeically like when they are doing the cinamonn bread (YUM YUM)

You are correct about the rudder on the Funtana, that's my mistake. After I posted that I went out and did a little measuring. They are larger in every sense. So in the case of the Funtana's I used hitec 5645's all around on 6 volt, more the enough for my piece of mind.

The original poster got his answer but I think we should start a poll on this debate here in the 3D forum. I'm enjoying the heck out of it and I am now curious as to what the membership thinks. Wadda ya think?

Something like

What surface do you put the strongest servo on when talking about 3D planes and 3D flying or something along those lines

You can fly the plane without rudder. But the rudder is the most important when choosing servos torque wise, and for reliability. Think about this, the rudder is directly in line with the prop blast, even more so than the elevator. The elevator and ailerons are take a lot less torque than you think. There is somewhere a calculator that tells you how much torque you need, and the rudder was way more than the others. I think that on a 28% extra with 3d surfaces, the aileron and elevator only needed 45oz in, and the rudder needed 168oz in!

just my 2 cents.

Great post guys, you both have great points and are right. I would love to see that POLL, it would be an interesting one...

Here's the poll

http://www.rcuniverse.com/forum/m_3678516/tm.htm

I didnt know the P-6E Hawk was a 3D plane

As usual, Lee sees all. Amazing how far a question goes around the block before it gets answered