Zagi 400X, elevon mixing and control throws

If I recall correctly, the throws on the Zagi are set with the elevator at neutral. Just right and left stick input. If you are not getting enough throw, move the push rods outwards on the servo arms and inwards on the control horns. You should be able to get a ridiculous amount of travel on the elevons with a Flash 5X. I fly my 400X using that radio and have mine dialed up to Extreme Throws.

Yes, but in my case the throw is not limited by linkage geometry. It is limited by the gap between the outer edges of the elevons and the winglets. It is now only a 1/16", as suggested in building instructions. The size of this gap limits the elevon travel in upward direction (after a certain point elevon's corner bumps into the winglet). Of course, in order to allow for more throw I can always increase the gap and/or reshape the outer end of the elevon. Just wondering whether it is really necessary...

Right now my setup easily accommodates the suggested 3/8" of elevon throw, but not much more. What I don't exactly understand is how I should distribute this available 3/8" of throw between various stick positions. If I understood you correctly, you are saying that I'm supposed to get 3/8" of throw at, say, extreme right stick position (with neutral elevator). But in this case if I add some up elevator the throw will exceed 3/8" and one my right elevon will hit the winglet.

OK, you need to trim the elevons. They are too long. The winglets should NOT interfere with the elevons at all. The elevons are not supposed to extend beyond the end of the wing and actually should be about 1/8th of an inch or so short of the wing end. I will post a picture on alt.binaries.radio-control and can email a picture to you if you wish of what it should look like. The picture is actually my Trick RC Razor but its the same principal. Note that the red elevons are even with the end of the wing tips and clear the inside of the winglets.

Mine don't.

Mine are 1/16th of an inch short of the wing end, which is what building instructions recommend. I'm starting to believe that 1/8th of an inch is a better idea.

Unfortunately, you picture doesn't show the gap between the elevons and the winglets. Do you have a closer picture of these areas? I don't believe it is possible to have elevons even with the end of the wing. That will prevent them from deflecting upwards completely (or maybe they will deflect just a little). Because of the "parallelogram" shape of the elevons the upward throw is limited by the gap between the outer edge of the elevon and the winglet.

OK, I still dont understand how your elevons could be hitting the winglets. Something isnt right. I have built 2 different Zagis, a Razor, and a Wedgie, my buddy has built several of all three and neither of us have ever run into this problem. I have my pushrods on the outside hole of the servo arm and the bottom hole of the control horn and am running 125% or whatever the max is that the Flash 5X will program on high rates and am not having this problem. I have always cut my elevons flush with the end of the wing. The winglets have never interfered with them. I dunno what to tell you, but something aint right.

OK, let me try to explain it again.

This is the general shape of Zagi's elevon (let's take the right-hand one, looking from the top) ___ ________...________A ____ Axis of rotation \ \ \ \ Outboard end \________..._______\ B

(It is actually narrower at the inner end, but this doesn't matter in our case). Note the locations of point A and B.

Let's say outer ends of our elevons are flush with the wing end.

Let's imagine that we are looking at Zagi's right wing from the rear and the elevon is in neutral position. We'll see something like this

| |

OK, if I got this straight, based on your diagrams, your winglets are not taped to the outside end of the wing? Looking at my wings from the rear you get something like:

! ! !============X============!

X being the motor. The winglets are taped to the outside end of the wing with tape on the top of the wing going thru the slot in the winglet and around to the bottom side. This puts the winglets outside of the ends of the elevons. I will try to get outside and get a pic of my Zagi later and post it to alt.binaries.radio-control. Gotta hit the supermarket right now. :-)

Opps, I put 'B' in the wrong place. It was meant to be as follows

___ ________...________A ____ Axis of rotation \ \ \ \ Outboard end \________..._______\ B

Yes, they are. I don't understand what in my diagrams made you think they are not.

Yes, that exactly what my wings look like

I sounds like you put the elevons on the wrong side like I first did ! The edges of the elevons should be parallel to the motor shaft - they should NOT be swept outward as you appear to be sketching.

David

Also the elevons should get narrower toward the tip, not the root.

David

Yes, the edges of the elevons are parallel to the motor shaft in my case. What in my sketches seems to suggest otherwise?

No, elevons should get narrower toward the root and wider toward the tip. At least that's the way Zagi 400X was intended to be built by the manufacturer. You can see Zagi 400X instructuion book at TrickRC's Web site.

I have posted four pictures with some comments to alt.binaries.radio-control. The messages are named 'Zagi 400X elevon-winglet interference (1) - (4)'.

Once again, in order to avoid steering this discussion in wrong direction, I would like to reiterate: what is shown in these pictures is perfectly normal. This _must_ happen in any Zagi built in accordance with manufacturer's instructions. If your Zagi doesn't do that, it means that you built it "incorrectly" (no offense, "incorrectly" in this case means "differently from how the instructions tell you to build it").

My question is not about why this happens. (I know why this happens. Moreover, I know that this must happen.) My question is about the size of the gap between the winglet and the elevon in neutral position. Currently I have 1/16", which allows for upward throw shown in pictures

2 and 3. Do you think this is enough? If it is not, then I'll increase the aforementioned gap and that will give me more upward throw. This will require re-hinging both elevons, but what must be done, must be done.

Looked at the pix. I guess mine just flex the winglets out to the sides. Mine are cut exactly as yours but I still get full range of motion with my elevons. I might have a bit of a bigger gap but if so, it isnt much. My elevons deflect as far as the radio will make it with no binding that Ive seen and it flies like a champ. The HS81MG servos are in their second 400X, the first 400X having turned to mush from too many violent meetings with Terra Firma. Upgraded to a cobalt motor. That sucker will roll very quickly too. I dont know what to tell you.

Well, I will just re-hinge the elevons slightly closer to the centerline in order to get bigger clearance between their outer ends and the winglets. The inner ends of the elevons will intrude a bit into the prop cutout, but it doesn't appear to be a problem. I don't wont to cut or reshape the elevons at either end because I have already covered them with Monocote. BTW, I also use HS81MG.

Thank you for your replies.