Melchizedek

Hi,
was wondering how much rotation each way should a S3152 futaba servo turn, 1/8 , 1/4, 3/8, 1/2 ?

My situation.

I am new to RC. I am building a Sig Kadet LT 40 Kit.
My building skills are good (am a cabinet maker) but my radio skills are zero and moving up.
The Radio I am using is a Futaba 7c-2.4 GHz .
I am making modifications to the Kadet.
I am going dual servo Flaperons and employing a Rotary Drive System for the Flaperons.

In the radio menue I was able to activate the flaperons using chanel 1 and 6.
They both turn with the aileron stick but they only turn 1/8 revolution each way.
The Aileron Dual Rate Switch has no effect on the rotation.
With only 1/8 revolution my RDS won't lift and lower the ailerons much.

Am I missing something in the menue, or is this servo only designed to rotate 1/8 turn each way ?

Kevin

rgm762

My Feedback: (4)

there's going to be a few questions asked in order to get the info you need like how are you measuring your travel?

Hossfly

Deleted by poster.

Melchizedek

Ray,

measuring travel by how much output shaft is rotatiing. Index point rotating 1/8 turn.
Simple question, will the servo rotate more than 1/8 a turn by tweeking something in the transmiter ?

Melchizedek

Horace,

asked a simple question about servo rotation.

I provided some background on what i was doing to help someone visualize what my intentions were.
I expicitly said I was employing an RDS system. Not a tradiional servo arm and horn.

What I did not ask for is a rebuke!

I intend to learn to fly via buddy box with an experience pilot.
How my ailerons are configured to function will not mater so long as they function properly.
I have very good mechanical skills and am atalented craftsman.
If I stretch the envelope on the building side (it will still be a Kadet trainer) and learn to fly the proper way (and i do) whats the wooop?
The flaperons will be us as ailerons until I am proficient enough a pilot to play with the flaps.
This hobby for me is about having fun. Altering this kit without changing the airodynamics is fun for me and will not impead my learning to fly.



Kevin

rgm762

My Feedback: (4)

one thing to do is go into the programming on your radio and check the EPA (end point adjustment) should be set at 100% on ch 1 for the alierons. you can use this setting to fine tune the travel on your control surfaces

Melchizedek

Ray, thanks for your response.

Checked channel 1. It is set at 100 %. Checked channe 6 (the other aileron servo) it is set to 100 % also.
That menue allowed to change the space next to the100% to max 140%. I did that for both channels. It seemed to let it turn a little farther in one direction. But not near a 1/4 turn.

Does anybody know what the max or standardrotation of futaba s3152 sevo is ?
Maybe wrong servo for my aplication or mabe missing a tweek ?

Kevin

jester_s1

I have those servos on a couple of planes, and they will definitely turn more than 1/8 turn. I've never actually measured their max travel but it's at least 90 degrees (1/4 turn). You may try hooking one up into a different channel that's set on 100% ATV and just see if it will move more. That lets you eliminate the servo as the culprit. That said, with most standard linkages 45 degrees of travel will give you enough throw for most things you'll ever want to do with a trainer.

maukaonyx

I use that servo routinely. Just took a new one out and measured the throw at about 100 degrees from stop to stop. It sounds like your transmitter has some programming in it that is limiting the throw, so you will need to work through all the settings and switches to find the culprit. Be sure to test the servo like someone said, by plugging it into another channel to see if it gets full throw there. Good luck. Jon

Battle Short

My Feedback: (5)

Have you checked the position of the channel that controls the flaps? Maybe it reduces the aileron rate when the flaps are down? I'm just taking a stab in the dark here...

JollyPopper

My Feedback: (6)

The 3152 is a good servo. It is a digital, hi-torque, single bearing servo with 90 degrees of rotation. That is 45 degrees each way from center or 1/8 of a rotation. As mentioned earlier, you can bump that up to 140 degrees from the transmitter, but it probably is not necessary. The LT40 is a wonderful flyiing airplane, but it is a trainer designed to be very forgiving to the beginner, thus the smaller control surface movements. You might want to try flying the plane at 100% EPA and play with mechanically adjusting the total movement by moving the rod in the servo arm and control horn. Further out on the servo arm and further in on the control horn will give move movement.

The 3152 is a very good economical servo. You won't do better in that price range.

JollyPopper

My Feedback: (6)

ooops, my bad. You clearly said you were using an RDS system, so I have no idea how my previous post impacts that since I have no idea how an RDS system works.

I still stand by my opinion of the S3152 servo.

757jonp

My Feedback: (48)

I still trying to picture a "rotary drive system" (RDS). Could you elaborate on that?

I to use the 3152 servos and agree they should have at least 100 degrees of rotation. Somewhere in the radio programing is the problem.

OliverJacob

My Feedback: (12)

I don't know what the RDS means, but I have these servos and they will turn more then 1/8 in the standard radio settings.
Just to eliminate a possible problem, I'd take the flaperon mix out (don't see why you'd need flaps on a Kadet).

It looks like the problem has to do with the flaperon mix.

Villa

Hi Melchizedek
I just realized that I completely missunderstood your post. I suspect others did too. You mentioned that the servo travel is only 1/8 revolution. I am so used to seeing 45 degrees instead of 1/8 revolution that I did not immediately realize that 1/8 revolution is 45 degrees. My bad. I don't know that particular servo, so I don'tnow what the normal travel for it is. Most servos travel about 45 degrees, or I/8 revolution.

jaka

Hi!
45 degrees to the left and 45degrees to the right!
Total 90 degrees.
But the trawel could be alltered to 140 degrees. Go to Travel adjustment =JR/Spektrum language. Don't know what's it called by Futaba.

Instructor

My Feedback: (16)

Hi Kevin,

Are you asking what the total travel is for the flaps or the ailerons? If the ailerons are traveling enough and the flaps are not, then you have to set the flap servo like this: Take your servo arm off the servo, move the flap knob/switch to the max throw for down flap. Now reattach the servo arm at this position. Move the flap knob/swith to the full up flap position. Is this enough to make the flap go back to neutral? If not, then you will have tomove the aileron link closer to the aileron so the travel can be increased. If it is too much and the servo buzzes, then move the linkage fauther away from the aileron. You can also adj this through the ATV on you radio for each channel. I realize you are using flaperons, but the travel for each function needs to be adjusted this way. If you still have questions, PM me and I'll see if I can help.....

Larry

rlipsett

I am trying to remember how to do this but in essence the full travel of your servo is in reserve for use as a flap. I do not remeber if disabling channel six would allow you to have full use of the servos. I have been using a 9c for awhile and I use aild diff mode to use 2 servos for my ailerons. I never looked at the manula for a 7c 2.4

OliverJacob

My Feedback: (12)

...thinking about it, 1/8 in each direction is about right. This servo is no different then any standard servo regarding the travel.

I guess we all like to know what a rotary drive system is.

Probably your invention?
Please find a club near you and have somebody look over your setup.

A lot of things can go wrong when you just make a few changes, but maybe you have invented something really good. We don't know
what you did so there is not much one can help with this on here.

Melchizedek

I want to thank everybody for there kind responses.
Some of you have asked what a Rotory Drive System (RDS) is.
If you click the link you will find lots of info and the benefits of this system.

www.geniebuild.com/g2_rds.html

Some of you are probably thinking. Why not just build your Sig Kadet LT 40 as designed ?
Well , truth is, this is not the plane I really want to build, but I have to learn how to fly first.
What I want to build is a War Bird. First things first.
When I get around to building a P40 or P51 or jug. I will use the RDS on those planes.
So the Kadet will not just teach me to fly. I will learn emplementation of this system.

Back to servo rotation.
If you clicked the link you will see the bent control rod that deflects the aileron.
With 1/8 rotation left and 1/8 right. I can only get half of the intended deflection.
The deflection rod is bent at 30 degrees. With only 1/8 rotation it will be at best 15 degrees.
If the servo rotated 1/4 left and 1/4 right I could get all 30 degrees of deflection.

I checked my other servos on my other channels and they all rotat 1/8 left and 1/8 right.
So my guess is that is there travel.
If that is the case then I need a steeper bent deflection rod if I want more than 15 degrees deflection.




Kevin

2walla

My Feedback: (10)

Check the dual rate settings on the transmitter also, they could be reducing the throw. You should be able to get about 60 degrees each direction or 120 degrees total if you max everything out on the transmitter. You may want to look around, there are some better ways to do internal linkages. Durant? direct drive has a system and i want to say i have seen some hinges that translate linear motion to control surface rotation. . Any slop can result in flutter and destruction of your plane. I used to go for cool internal linkages but after loosing a plane simple, and reliable becomes more important than looks. Good luck

You may want to look on some of the glider forums. I seem to remember harley michaellis using similar linkages years ago on a couple of his designs...

maukaonyx

Ok, now from your pics and link, we know what that RDS system is! Sounds like you are getting about the right servo throw each direction with 1/8 circle in EACH direction. If you want more throw you are going to need to crank up the end points of those servos via the transmitter. Jon

jester_s1

He can't go 90 degrees on the control rod unless he wants the servo to be hanging out of the hinge line. But yes, you have all the throw you are going to get from that servo already. How much actual deflection are you looking to get for your flaps?

jaka

Hi!
I used the RDS system 30 or more years ago when a Swedish company made plastic components that worked the same as RDS do.
But it wasn't that good! It had lot's of play built in so I only used it once!
The problem with the RDS system is that the play between the rod and the slot must be very, very small,otherwise you will get lot's of play in the ailerons.

I think it's good thing to practise on a simpler plane first and see how the system works. As you seem to be newbie I don't think it's advisable to use the RDS system on your first plane. That plane will crash sooner or later so do not invest too much time in it with elaborate controll systems, much better to just use a ordinary aileron set up with one servo and learn how to fly first!
Then when you have learnt to fly after a couple of months/years (depending how old or knowlegeble you are)...then try the RDS sytem.

JollyPopper

My Feedback: (6)

I asked Servo City if they had servos that would rotate more than 90 degrees total. They replied that their Hitec programmable servos would rotate up to 180 degrees using the Hitec programmer. They didn't say if that was 180 degrees each way or 180 total but it is more than what you have now.