slopeguy

I am having trouble with my Zagi 5C. When I launch the wing flies great, straight into the wind. If I make at turn to bring it back to the face of the hill I have trouble getting it turned back into the wind. The plane will not roll, and it will not loop. Inverted flight can not be done because I can't get the plane to roll over. I have re-balanced it checked to see if the manufacture marked the wings wrong etc... I can't figure it out. I flew a friends and it flies great, Did I do something wrong when I built it ? Any help would be appreciated.
Thanks

Futile Flight

I suppose that the first thing I would check is the throws of the elevons. It sounds like they may be set too low. If they are, you will also find that the wing will not be nearly as responsive.

-Paige

marcellus

It does sound like a lack of control surface movement or perhaps blow back of the control surfaces if the linkages are sloppy, or the push rods are bending under load.
It will be less responsive to turn commands coming downwind; though it's ground speed may look high, it's airspeed moving with the wind may be very low. A dab of down elevator before aileron will speed it up and make it more responsive but it sounds lake a lack of control movement. These wings are usually too responsive on first flights!

Are your servos moving in the cut outs?

slopeguy

I have a lot off throw in the surfaces. I'm gonna guess at least 3/4" both ways. It may be push rods though, however the other guys have the same rods and they don't seem to be having the frouble that I am with this particular plane.

Here is another one for you that had the guys at the field a little baffeled. I striped a servo on the plane and replaced it with a futaba servo. The Futaba servo would not work with the Hitec receiver and transmitter. The controls were completel oposite what they should be. EXAMPLE:
When you push forward on the stick the plane would actually turn and when you push the stick to the right the plane would climb. I know what you are thinking, this guy has the servos reversed at the receiver...not so, I switched them, same thing. They would not work with the Futaba servo, I hooked a mini Hitec servo to the receiver and it worked fine. What is up with this ?
Thanks

Tall Paul

Swap the channels your servos are plugged into.

slopeguy

Did that also, thinking that all I had to do was switch them. This did nothing, the controls were still backwards. The only way to fix it was to go with Hitec servo. I thought a servo was a servo only the plug and gearing was different. Could it have something to do with the plane using elevons and it has something to do with the servo. The three guys at the flying field tried every conceivable combination and nothing worked until I got home and plugged in a Hitec servo in place of the Futaba. Does this give you any other ideas?
Thanks

marcellus

Hitec servos rotate the opposite way to Futaba servos. That's how it is!
As you are flying a wing the two surfaces that you'd expect to move in opposite directions - i.e. as ailerons - are moving in the same direction and therefore act as elevators. Can you correct the direction of the servo by reversing it in your radio? Computer radios will do this easily but even the simplest of radios usually have jumpers to do this. It should be in the manual.

marcellus

On second thoughts, the simple wire push rods that most use on a Zagi is more than adequate so blow back is unlikely unless the servo is moving in the cut out.
The other thing that can make a plane unresponsive to control commands is a forward CoG. Have you balanced it on a pencil as they usually suggest. Their CoG recommendation can usually be moved back 0.5" but it will fly and respond fine where they suggest. Is the way you have hinged it OK? Slop free and allowing the surface to rotate up and down along the hinge line?
I suggest you get your budy, whose Zagi flies ok to take a look at things!

BlackB12

My Feedback: (9)

It's very odd that with 3/4 inch throws that it can't roll or loop. If the throws really are that much, the wing must simply be VERY nose heavy or you're just trying to fly it too slow. As mentioned above, check your CG. I found that mine really flies responsive with it balanced at 8 inches from the nose.


Mike

slopemeno

My Feedback: (2)

Things to check:
Does your radio even support V-tail or elevon mixing? If not, you may need to pop for a v-tail mixer that goes between the receiver and servos.

ANY set of servos from the same manufacturer will work, you just have use the servo reversing function, then swap the servo plugs in the receiver.

.75" is a huge throw for elevators, you must have your CG pretty far foreward. As previously suggested, 8" back from the nose is a good CG. Most 'chevron' type wings seem to work well with a 2-to-1 ratio of aileron to elevator throw. Adjust the elevator trim until you get a smooth, fast, flat glide. The faster you fly the more efficent it will be.

And something to consider: Maybe your hill just doesnt provide enough "oomph" to get this thing dialed in. If there is a steeper, windier hill to fly at, try it. Good lift is a treat.

slopeguy

Thanks for all of your help on this. I have tried to reverse the servos on the transmitter and that will not change the throw of the Futaba servo. The only way to get the servo to travel in the correct direction is to turn off the elevon mixing at the transmitter, then the servo will reverse. This is no good because then I don't have the necessary mixing for elevons.

I balanced the plane at 8" back which is on the rear carbon fiber reinforcement in the wing. It took 1 and a half oz. to get it balanced. The hill that we fly from has great up lift and actually gets a lot of compression at the top of it. I have tried it in winds of 10mph to 26 mph and get the same results.

I really appreciate your input on this and I don't want to sound like I am ignoring your suggestion because I'm not, I have just tried most of your suggestions.

I honestly believe that it is caused by the servo (Futaba) because it works fine with the Hitec servo. I ordered 3 new servos (Hitec) and I'm sure that this will be the remedy. Just wondered if anyone else ever ran into this problem. As soon as I get the servos and get them in the plane I will try your recommendations and see if we can get this thing to fly. I will keep you all posted, and again THANKS GUYS !

BlackB12

My Feedback: (9)

Servo make has nothing to do with your problem. A guy at the slope has a mismatched set of servos in his zagi, he's got both a Futaba and a hitec. I have two futaba servos in my Zagi and two hitecs in my M60 slope wing. they both work and move in the right direction. the only thing I had to do was reverse the elevator function with the M60 running the hitecs. Are you sure you have them plugged into the correct ports on the receiver? I think if you keep messing around with it you'll find the right connection. At first I'd either have the elevator correct and the ailerons reversed or vice versa until I came across the right combo or plugs and servo reversing. Also are the elevons moving up and down the same amount? If you've got it balanced at 8 inches back and with that much throw the thing should be downright squirrelly, not sluggish.

Mike

slopeguy

How you doing Mike,
I have tried as many combinations that I could figure and still had nothing. Let me try to explain what it is doing in more detail if I can. If i push the stick forward for down ailerons only one aileron goes down, the other goes up. If I push the stick to the left both ailerons go down and the oposite when I push the stick to the right. When it first did this I thought oh all I have to do is reverse the two servo connections at the receiver...Wrong. So I then thought well maybe I need to reverse the servos at the transmitter...Wrong. I brought the plane home switched crystals for my other radio and it did the same thing. Hooked a Hytec mini servo to the receiver and it worked the way it should. I tried every combination I could think of when changing the servo plugs at the receiver example 1 and 2, 2 and 1, 1 and 3, etc... I know this is rediculas butI can't get it to work. Now If I hold the transmitter with the right side up and the antenna sticking straight out to my left everthing is ok, but I would look like an idiot. Thanks Mike for your help. Does this give you any more thoughts as to what can cause this ?

BlackB12

My Feedback: (9)

Wow, I have NO idea then why that is happening. WHat receiver and what transmitter are you using?

Mike

marcellus

This isn't a mystery at all!!!

If it works with the HT servos then the elevon programme set up is working fine. BUT Futaba servos rotate the opposite way to HT, for a given command. So your getting what looks like elevator response to an aileron command and vice versa!!

If your Tx has an elevon programme in it, I BET it also has servo reversing there also. You can reverse the rotation direction of the Futaba servos ( as Mike had to above) using this and then they will behave the same way as the HT servos. You may even to be able to do the same thing in the elevon programme but keep in simple and use servo reversing.

The only mystery is why your wing wouldn't roll!!

What Transmitter model is it??

slopeguy

It is a Hitec Focus 3 that they sell with the plan as a kit. It has a mixing switch on the back along with 2 servo reverse switches. I tried changing them all and it did not change the throw of the Futaba servo.

slopeguy

Hey Mike, I am using a Hitec Focus 3 Fm with a Hitec receiver. Zagi sells the wing with all the necassary parts and a radio as a ARF kit. That is what I bought when I purchased the Plane.

marcellus

The HT manual says the two reversing switches will change the servo direction of chanels 1 and 2. If they don't then it is a mystery and something is wrong...

Tomi

My Feedback: (4)

When you fly back into the slope, and you're flying slow. It's most likely you're going the same speed as the wind. Or not fast enough for the air to pass over the elevons. So your wing isn't going to do anything but hit the hill. That is why you NEVER fly downwind on a slope unless you have enough speed. Always fly parallel to the hill and keep the nose pointing the wind.

That's my opinion..

-Tomi

slopeguy

Ok guys I got my 3 new Hitec 322HD servos today, took the Futaba servo out and put the Hitec in and everything works fine now. I also got my new Discus that everyone has been talking about. I thought it was a good plan and can't wait to get to work on it. After checking everything out I bought 2 more [X(]. I bought one for a buddy and will keep the other for myself. I can't see how you can go wrong for $175.00 each for a 157" wingspan sailplane. The thing looks awesome and the quality of the wings and fuse a great as far as appearance. I am doing a little bit of rework on the internal wood parts because the glue they use seems to never hold very well, but what the heck.

slopeguy

Took the Zagi out to the hill today, added another 1.25 oz of nose weight and flew the crap out of it. Air was 15 to 25 from the NW and really choppy. But all in all had a good day at it. Really glad to get the thing flying right. Thanks for all the help and advise that I got from ALL of you !
Dan