VictoryRoll

My Feedback: (2)

Hey All !

I am hoping this is the correct forum in which to ask this question... if not, let me know and I will ask moderator to move accordingly.

Anyway, what I would like to know is how does one best create a servo bay in the fuse of a new ARF.

The plane I am building is the GP Big Stik 40 ARF, and I would like to stick a servo in front of the rudder, top-side, and run a pull-pull system, but I have zero experience in doing this. Questions like:
1) At what point should I make the hole in the fuse? (I mean how far away (or close) to the rudder should the hole be)?
2) After cutting the hole in the fuse, I suspect I should strengthen the underlying area around the cutout with plywood of some sort, am I right?
3) What else should I know/do

Thanks so much for your help! I am really excited about this build and want it to go really well, as well as look and work great. Any and all suggestions are appreciated !

Thanks again !

P.S. The GP Big Stik manual is here: http://manuals.hobbico.com/gpm/gpma1220-1221-manual.pdf

P.S.S. If it matters, I will be running a OS 55AX engine.

Don

dignlivn

Don,


Why a pull/pull, just put a high torque servo
for the rudder JMO.

Bob

MinnFlyer

My Feedback: (4)

You can do a pull-pull without moving the servo. Just mount it in the center of the servo tray.

da Rock

1. The fin will make you place the servo far enough away that the arc of the servo arm and horns won't be a problem. Servos can be really close, but usually aren't.
2. Yes, you're right. The mounting screws need something strong to bite into. And the tray gives support to balsa sticks that weren't sized to carry a load. The ply doesn't have to be really thick for that job. Since you need some thickness for the screws, add some where they'll be.
3. What else? Look at the models that have remote setups. It's a pretty simple deal.

BTW, your idea has quite a bit of merit. Shortening pushrods is a good idea. But moving weight around needs study. Do it before you cut. Tape a servo where you want this one to be, maybe even a bit of ply with it. Then look how far the CG moves. If it is within the original CG range, nothing more needs to be done other than maybe moving the elevator pushrod one hole out in the horn. If it isn't, then move the battery or something.

Deadeye

I'll second what darock says, and maybe you can get a better idea with the following picture. This one is sealed for water use, but making it exposed should be no problem.

VictoryRoll

My Feedback: (2)

Thanks guys !

All inputs have been great, esp. da Rock ! da Rock, thank you for all of that info.. much appreciated... I didn't even think about the CG.. duh !! The idea of taping the servo and determining the best location w/ respect to all INCLUDING the CG is perfect and exactly the feedback I was looking for. The Big Stik is known to be a bit nose heavy and this is one of the reasons why I wanted to move the servo back, although not the main reason. Main reason being two points, one is to get better action on the rudder with shorter throws, and the second is to do something I have never done... move a servo on an ARF (or any model for that matter). I just want to build in this manner and see how it all works. I did post a separate thread ( if you wish to look at it you can find it here: http://www.rcuniverse.com/forum/m_8062488/tm.htm ) and one of the respondents "Ed Moorman" showed (post #6) some pics of his tail-feathers on the Big Stik and this is the setup he used. I have "hit him up" for other questions and although I KNOW he would never have a problem w/ me asking him this question, I did not want to keep bothering one person with every question I have on a build..lol.. He is a fine fellow (what I know of him) and as mentioned he would understand and be there for me w/o question... I just didn't want to wear out the welcome, if ya know what I mean.... Additionally, and just as importantly, I wanted other inputs from the "masses" to see what kind of considerations and options I should be mindful of during build.

BTW, Deadeye, love the plane, and esp. the "Raw Dog".. good stuff... and a pic is worth the proverbial 1000, so I do appreciate you taking the time to post that pic!

MinnFlyer, although I would like to try this move, I did not think about what you proposed... moving the servo to middle bay... great idea, and if all does not work out for the best, I will definitely do just that.. thanks for your input!

Thanks again all... if you want to add anything else, it would be appreciated.

Best to you,

Don

Deadeye

Here's the plane as a whole. Love my Sirius!

Minnreefer

Dead eye, how did you seal up your servos to prevent water from coming in?

Thanks

Deadeye

They are mounted beneath the surface and a hatch is built over them with just a small hole for the output gear to poke through, but big enough that you can get a horn on. Probably unneccesary, as most servos are water proof/resistant from the factory.