Flair scout SE5A

[Max Trent]

Into a scout SE5A build and thinking of servo options shortly.

When ever i run into a prob and post for help i always say "this is my 1st real build" and new to the hobby.So once again i have no idea what servo`s to go for.

I think full size will fit no problem at but do i need full size?

The ailerons are shown worked by 1 servo monted central but i have read that its best to use i in each wing,full size will not fit here for sure.

If anyone can tell me what sort of torque i will need for ailerons and then ele and rudder.I suppose a bog standard will do for throttle,intend to fit sc56fs.

Will soon be starting on the wings so i will be needing "how to" fit servo`s in wing panels soon!

[Richard Wood]

Standard servos such as Hitec 311/322 or Futaba 3003/148 or similar

will be best for rudder, elevator & throttle.

Metal geared mini servos such as Hitec 82MG/85MG will be good for

wing mounted aileron servos. Plastic geared mini servos can be a bit

fragile.

I fitted Supertec 'Park' minis as aileron servos in a Magnatilla wing & these

have been fine - they are a bit bigger than other 'minis' though.

[Eck]

Good plan! I bought a second hand one last year with the original central servo/bellcranks arrangement and it's a NIGHTMARE! As Richard said, metal geared minis is the way to go, as each one is pushing two ailerons.

Mine is fitted with an elderly SC 52 FS turning a 12x6 and circuits are flown on no more than half throttle, but it has roughly 6oz. of lead in the nose for balance - keep that rear end light!

[andy watson]

Pretty much any bog standard full size servos will be fine. Basic Futaba 3003s or similar.

Don't waste your money on anything fancier- they are just not needed for a smallish plane that will tootle around the sky at low speeds doing geriatric aerobatics at best.

[Richard Wood]

I also found the central servo with pushrod & bellcrank arrangement

in the Magna to be very difficult to set up without slop & I removed it.

One servo for each side is easier.

 

Edited By Richard Wood on 28/02/2012 13:08:08

[Max Trent]

Richard,Eck, Dont suppose you have any pictures of the servos in the wing? Not sure of the method to mount them.

Do you sheet that area and sit the servo on that? or have them on rails that span two ribs?

I have no idea on either method to be honest.

[Richard Wood]

Hi Max,

The arrangement I used in the Magna was very similar to this in the Webbit

I built last year:

Servo mounting beams glued between ribs with strip reinforcements.

balsa sheeting added around servo area for covering to anchor to.

There are other ways to do it of course - you can mount the servo on it's side

& hatch it all in with just the control lever exposed.

Don't forget to install servo extension cables before covering the wing!

[Richard Wood]

If you wish you can install a paper or thin card tube through the ribs

for the servo extension cables to run through.

This could allow you to fit these cables after covering & also give

subsequent access to them if routed correctly.

Use lead locks or tape on plug/socket connections.

Edited By Richard Wood on 29/02/2012 09:31:12

[Ed Darter]

used standard JR591's throughout when I built mine. Even in each bottom wing for the ailerons. They do fit, just, if you get them as far forward as you can towards the main spars.

[Max Trent]

Thanks for the advice all.I can not totally see the method in Richards picture.Using the the rail method he suggests is it just a case of gluing a balsa strip along the rib then resting the rails on this? And in that bay used i need to sheet the bottom flush ribs and make a slot for servo arm.

Mentioning servo arms reminded me,what do you aim for with the amount of arm showing,i have visions of installling the servo only to find its travel is wrong. I mean that if too much arm is showing i can cut the arm down but that means i get less travel.What do you guys aim for,the plans show no linkage rod from aileron servo`s so i do not know how far above wing sheeting the link should be,hope you understand that.

[Tim Hooper]

Max,

 

Here's a shot of the hatch-mounted servos in one of my models. Wood blocks are glued to the inside face of the hatch, and the servo screwed to these with the arm protruding through a slot.

How much throw you need will obviously depend on the model itself and your style of flying.

The hatch itself is then screwed to rails that run between two of the ribs.

With the servos centred electronically (using the tx), I rake the servo arms forwards by a spline or two to mechanically induce some differential - ie., more 'up' travel than 'down'.

Tried and tested on thousands of models over the decades......

tim

Edited By Tim Hooper on 01/03/2012 09:23:03

[Djay]

The easiest way is to fit two hardwood 1/4 sq rails in the bay you want the servo, cutting the ribs so the rail sits just below the top of the rib.

space them wide enough apart for the servo to sit between them, then make a ply hatch to sit over the rails, and fit the servo on its side to the hatch, using a small hardwood block epoxied to the hatch for the servo to screw to and cut a slot for the servo arm to pass through.

The hatch screws to the rails in the bay, so makes the servo easily removable.

Put pull strings in the wing before you cover to pull the wires through afterwards.

yopu can put smaller servos in the wings instead of one standard size.

Done this on all my Flair kits, and other kits as well and always quick and easy and works a treat.

 

Darryl

 

posted same time as Tim, the same thing as well.

Edited By Djay on 01/03/2012 09:22:21

[Tim Hooper]

Further to Darryl's post;

I inset the rails just below the bottom surface of the wing, so the hatch will lie flush with the surface when finally screwed into postion.

tim

[Richard Wood]

The 1/4 square hardwood strips were cut & sanded to be a snug fit

between the ribs & then glued in place with epoxy.The balsa strips were

then similarly cut to be a snug fit & glued to the rib, the hardwood servo beams,

the main spar & TE. It is quite secure.

You could add another balsa strip on top of the hardwood beams

if you wish & also rib doublers if you want belt 'n braces - this might be worthwhile

if using a larger servo.

The top picture is looking at the top of the wing incidentally.

The sheeting around the servo area on the bottom is the same balsa

thickness as the rib cap strips - which it effectively replaces in this area.

 

Enough servo arm needs to be exposed so there is good clearance & no

binding or fouling of the clevis or pushrod etc. on the wing surface.

Compensate for any excess servo arm travel by moving the clevis onto

an outer hole on the aileron control horn and/or by using EPA or rate

adjustments at the transmitter.

Hope this clarifies things a bit better

 

Sorry about the extra lines in the post - dunno why this is happening

Servos are of course exposed with this method - if you want it all covered up with

a hatch with just an arm sticking out -  follow the other lads' method.

 

 

 

Edited By Richard Wood on 01/03/2012 09:36:31

[Max Trent]

Getting the jist now guys,think i can manage to sort something out.Thanks for the help.

Laying out the first wing panel and see a possible prob,i am going to ask for advice in a new post incase i start with a prob i can not correct.

[Ed Darter]

I did the same as Tims method, but on the SE5a I was worried that the finish on the wing underside would look odd in this area given the rest of the structure is open. To get round this I made sure the hatch was recessed inside the wing a little further, then added a thin cap strip around its edges to make it flush with the rest of the underside. Then when it was covered it had the same effect as an open structure, perhaps a little overkill but works a treat. Just make sure there is enough capping material in each corner to accomodate the hatch securing screws, and harden it with CA or something in that area.

Ed