Flying Stab Question re Sagitta 600

[Whorges]

I'm just about done building and one of the things I'm concerned about before I fly is how do I set the trim position of the Stabilator? This is my first full flying stab. Usually I'd just put the elevator in line with the stab. I guess now I have to try to guess at 2 degrees or so of decalage??? If I run with the plane in my hand should I be able to feel pitching moments if the trim is off? Please advise. Thanks, Whorges

PS This is also my first plane with stabs and wings that plug onto rods. How do you secure the wings and stabs?

[Ollie]

For first glide with safe CG and safe 1 degree to 2 degree declage is OK. From there, adjust CG and declage with very small changes between testing flights. It's worth the time to adjust to your flying needs. Tune up the model for beatiful performance.

[flystoolow]

Stab Trim:

Seems scary, but nothing dramatic is going to happen as long as it appears pretty level. It will only be a few clicks of trim off at most, and the plane may gently pitch up or down. Running with it and letting it fly a second or two above your hand is good for piece of mind.

Securing wings:

Between the roots, attach an eye hook, a small spring with looped ends (hardware store), and a regular hook (and epoxy hooks into roots). Easy and strong.

Securing stabs:

Pull the pins, bang two small chisel dents near the ends of both rods. Maybe there is a better way (tiny set screws are nice), but that is how mine are done and they hold well.

Good luck

[schrederman]

Don't guess. You have too much time invested in the model to crack it up on the first toss. :eek:

First verify the CG to be mid range. Then set the wing at 0 degrees. I do this by blocking it all up until the center of the leading edge radius is exactly the same distance from the building surface as the trailing edge. I then set my stab 1/16" to 3/32" higher at the trailing edge than at the leading edge, depending on the stab chord. It has never failed to be a good starting point for first flights.

Enjoy... Sagittas are nice models...

Jack Womack

[OVSS Boss]

CG at root is 37% of root cord from the LE, that is a well confirmed numbrer. also, what Jack said is good, and then to confirm, run with the thing and see how it feels, is it going up or down or neutral, seems houkie, but will give you a final check before a toss or launch. The 600 will hand toss well, if you have a friend that is all the better.

Marc

[atjurhs]

I created a full-flying stab for my OLY2, hence I really had no basis for where to set the decalge on my stab either. The plan for the OLY2 actually indicated 0deg for the normal OLY2 elevator. Carbon Art's Performance Tuning Video indicated that 2deg was probably a maximum value not to exceed for most planes. So I intentially set mine with a forward CG value (but within the recommended range) and 0deg decalage. Then a buddy of mine made the throw, he has a really good arm for throwing straight and level, and I flew the plane. But before the toss another friend (who happens to be an LSF5) started grilling me on "what ifs" for the first flight, and the answer to each of these was "fly the plane".

So there's my suggestion. Set a forward CG, set a decalage between 0-2deg, have a friend toss it for you, and be ready to fly the plane.

Good luck!

[BMatthews]

Good advice all.

In addition to all the other help I suggest you try the running thing. I've rough trimmed two models with that technique and found that it works amazingly well if you have the sense of feel to read what the model is telling you.

Run into the wind and try to feel for the model either not getting light at all (not enough decalage) or trying to get TOO light and even pitching nose up in your grip (obviously too much decalage). You're aiming for a balanced but light feel when the model is gripped lightly between two or three fingers placed just under the wing at the CG location.

That'll set you up for the first winch or highstart launch. If you got the feel right you'll only need two or three clicks of trim to set up a nice floaty but not slow glide. When you have that set then use a permanent felt marker to mark the leading edge point so you can reset the trim easily to that reference. You may never again set the trim dead on that mark but at least it's there as a reference to return to that "happy spot".

A slight curve, but not a kink will hold the stab halves on nicely thanks to the springy action of the wire and the friction in the joiner tubes. A kink like you get from a set of pliers will be too fussy and will result in wearing out the slip tubes. A gentle curve will provide a consistent and non fussy grip for years.

At the wings you'll want to have an intermal rubber band, spring or some form of shear pin to retain the wings. A friction curve in 1/4 to 3/8 rod is harder to control and not recomended by me... :D

Another hint..... Air leakage at the joints is a known cause of high turbulence and drag. For that reason a lot of folks use adhesive tape to both seal the joint and provide the wing retention. But I've never been a fan of tape since it seems to loosen and lift the covering sooner or later. Instead I began glueing on a sealing gasket of craft store felt on the wing and stabilator roots 6 or 7 models ago. This seems to do a nice job of sealing the wing gaps and at the tail it provides a nice slip sheet sort of gasket on the all moving stabilator. And with any care at all it's not prone to wear or fraying even after hundreds of flights.

[Brner]

Good advice all.


Another hint..... Air leakage at the joints is a known cause of high turbulence and drag. For that reason a lot of folks use adhesive tape to both seal the joint and provide the wing retention. But I've never been a fan of tape since it seems to loosen and lift the covering sooner or later. Instead I began glueing on a sealing gasket of craft store felt on the wing and stabilator roots 6 or 7 models ago. This seems to do a nice job of sealing the wing gaps and at the tail it provides a nice slip sheet sort of gasket on the all moving stabilator. And with any care at all it's not prone to wear or fraying even after hundreds of flights.




Never used adhesive tape and sure wouldn't want to try it....but have used colored electricians tape.....variety of colors available these days...used it on all joints on my Legionair for years...just pull it off back against itself and not perpendicular to the surface and covering stays intact.

[sailhigh]

Consider buying an incident meter. One of the most useful tools I ever bought. One will last you a life time.