Just wondering if I should be able to 'wiggle' the elevator on my plane (the whole horizontal 'wing' - I can).

The horizontal stabilizer should be rock solid to the rest of the airframe. The elevator should have as little play as possible. You don't want flutter in control surfaces.

Yup, ideally no play.

In reality it's hard to get rid of ALL play, particularly in the smaller planes.

An overly large hole in a servo horn, a bit of lateral movement in the control rods, etc... all will cause a bit of play.

In something like a trainer, this is not a huge problem.

In a large surfaced plane, such as a 3D airplane, it can cause it to self destruct if flown too fast.

So in part it also depends upon which plane you are talking about.

Note:

If your linkages are otherwise tight, typically lateral bending or movement in the control rods is the biggest problem.

You can help to minimize this by installing a bit of wood against the fuse formers, etc. to "hold" the rods, preventing them from bending.

The rods can move back and forth freely, but the small wood piece with a hole in it for the rods, can prevent lateral movement.

Also check your servos. Sport servos, particularly the cheaper ones may have some play as the cogs can move a bit. This can lead to very slight movement, that translates to a larger movement on the control surfaces...

It's suppose to be rock solid..but there's going to play if you don't have a push/pull system.

Plus the stock cleves and horns arn't exactly precision.

(single rods)
It's always going to be stronger when it's pulling.

When it's pushing...you can apply in the opposite presure to the control surface...you'll notice the rod will flex away from the fuelage.
Or if you apply more pressure in the same direction, it'll just flex more towrads the fuselage. lol


yes..you can wiggle the control surfaces it's not going to matter as much on a trainer or mild sunday fliers.
Verse on a speed deamon hotrod it might cuase fluttering.

But try to elimate or minimze the wiggle as much as you can.

That's why I have a gap fetish.lol
If you're using CA hinges..if you don't makesure they are properly install. That too can be another soure that'll caz play.

FatCat, My elevator doesn't wiggle at all, and you know what plane I have! Seems like you are having more problems than you should be with that plane. You musta' got the prototype lol

The stab should be rock solid. No slop or movement at all.

The elevator, well, slop can come from the linkage, on either end, or be in the servo with sloppy gearing. If you want tight servo's, spend the money and get some expensive servos. Otherwise, live with what you get. Normally, though, they are pretty solid. That leaves the linkage. The only slop is in what you put in, for instance, using 4-40 size control horns with 2-56 linkage. Not likely. If you drill out holes in the control horns or the servo arms, you will get slop. Not much but visible.

This is the same for any servo linkage. Slop usually comes from sloppy building or over-drilling, or the use of the wrong hardware.

CGr.

Other questions, are you wiggling your elevator while the plane is turned on or off? While off some servos can be moved quite easily.
Stabilizer? what do you mean by wiggle? It will flex some, after all it is made of balsa not steel. I can flex the stabs some on all of my airplanes. You should see the dance the tail feathers on a Kadet Senior do when you run it up to full throttle on the ground yet it flys like a dream.

Well if the rod flexes this much please get into the fuse and add some scrap balsa supports to eliminate this flex. Many arfs come this way but it can be deadly in a dive recovery situation. As a club safty inspector this kind of play gets a "no fly'' . But we usually help the guy make the repair at the field so he can fly.
The servo should move both ways under presure (radio off ) with no rod flex . this is true for all planes ( if your servo costs more than my trainer you can decide for yourself)

if your talking about the Nextar then the plastic thumb bolts are not tight enough, hand tighten them, then a 1-2 extra with some pliers does it, not so much that the fuse gets dammage just enough so the elevator is not sliding around, just using your fingers won't tighten it enough,after a few flights the plastic bolts need to be snugged up they become loose with the vibration of the engine and should be checked periodicly.
if you try hard enough the stab will move, don't force it to move, but if it's snug and not sliding back and forth and when you move the elevator with the radio then its fine.