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Old Sep 11, 2011, 08:48 PM
MK3
Aerial Loitering
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Easy star pulls to the right

Hey guys,

I wish I had done this test sooner (I wouldn't have climbed a fence and nearly broken my ankle retrieving the plane).

This is the RTF version. When I set the easy star on a table and apply power, it rotates to the right. It did this during the first flight, and no matter how much left rudder I input, it still turned right, ending in a clockwise death spiral.

The aileron and rudder are perfectly straight, and I even added a rudder mod. Still, no matter what, it largely favors right turns with the tabletop test. For now I can only do the tabletop test since I'm on crutches for at least a week.

Any ideas?
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Old Sep 11, 2011, 09:27 PM
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Make sure your wings aren't warped, and the horizontal and vertical control surfaces are perfectly straight.
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Old Sep 11, 2011, 09:55 PM
MK3
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Wings aren't the issue, since it's rear propeller and the tabletop test blows directly onto just the tail fin. However I did check all surfaces and they're perfectly straight and level

I actually found a YouTube video demonstrating the same problem, except the author of the video was having a different issue (my prop and engine is stock)

Multiplex EasyStar won't turn left (0 min 58 sec)
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Old Sep 12, 2011, 06:34 AM
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Originally Posted by dgpilot View Post
I actually found a YouTube video demonstrating the same problem, except the author of the video was having a different issue (my prop and engine is stock)
Assuming the fin is true, the plane in the video is yawing right either because of massive amounts of torque, or because the motor mount is skewed abnormally - or perhaps both. It may not have anything to do with your specific issue.

The strong tendency towards right turns that your own EZ* exhibits is certainly not "standard". If you're still using the brushed Permax 400, torque is minimal and insufficient to cause such a strong effect.

A useful technique that's talked about often on the main RCG EZ* thread, which I thoroughly recommend visiting, is to take photos of your plane from various "normal" angles and from a considerable distance (directly in front, direcly above, directly from the side) and then to draw overlaid lines through the fuse, stabilisers, and wings to check whether they appear to be aligned. The body of the plane would have to be significantly out-of-kilter in some respect to cause such a strong tendency to turn to one side.

Otherwise, if everything seems aligned, you may have a subtly broken wing. The end of the wing spar forms a high stress area where the wing foam may split in a hard landing. Unless you examine both wings carefully, it may not be obvious that one of them is a lot bendier than the other. In flight, the damaged wing bends upwards at the spar end (the wing is cracked underneath), and that causes it to lose considerable lift. The "strong" undamaged wing then causes the plane to roll into the weak side, thus triggering a turn.

If you try to hold your plane and deflect each wing upwards in a controlled fashion, is their resistance to bending approximately equal? If not, check underneath for cracks, especially where the spar stops.
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Old Sep 12, 2011, 11:30 AM
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I'm not at all convinced that the table top test you ran has any validity. Looks funny in that there is NO forward thrust, just the rotational forces of the prop/ motor. Prop on CORRECTLY??

I'll try this 'test' on mine that flies correctly..
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Old Sep 12, 2011, 04:29 PM
MK3
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It is a pretty valid test. Prop torque only tilts the plane left and right, until wings touch the table.
Technically, with the motor at medium to full power, a properly setup plane should NOT rotate like it is in that video. Clearly if it's rotating like that on a table then it's pulling unintended turns in flight, just like a experienced a few days ago

My setup is rtf, so the prop and motor were already in place, and they seem to be properly oriented
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Old Sep 12, 2011, 06:32 PM
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I don't think the table top test is giving you the correct response.

First..The bottom of the EZ is round. So, sitting on the table, lateral balance is going to play a big part in which way it has a tendency to turn.

Have you trimmed in left rudder and actually flown the plane? If you increased the size of your rudder, as the Mod you mentioned, I find it hard to believe that it would go right with full left rudder.

I personally think you are putting to much credence in your table top test.
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Old Sep 12, 2011, 08:30 PM
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Originally Posted by tacx View Post
I personally think you are putting to much credence in your table top test.
Agreed. It's really quite pointless.

Motor or prop torque will always pull one way or the other, depending on the direction of rotation. The EasyStar nacelle does not have built-in lateral compensation (the motor axis is parallel with the fuse when viewed from the top), and the motor+prop assembly is not at the CG. Therefore, there will always be some lateral force.

Depending on the composition of the flooring material and its level of friction, as well as th bottom of the fuselage and the "cleanliness" of both (dirt particles can reduce rolling resistance), the EZ* may be strongly stuck on its contact patch with the floor but free to rotate around because of the fulcrum between the motor+prop and the contact patch.

Rip the wings off that that further reduces the level of lateral stability.

It's really a test of nothing more than floor stickiness and motor torque.
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Old Sep 12, 2011, 09:33 PM
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Ok, so table test aside... During my first flight...What caused the easy star to continuously turn right even with trim set all the way left?

And again, rudder looks and responds perfectly when testing on ground. Aileron and tail fin checked many many times and are perfectly straight.
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Old Sep 12, 2011, 11:49 PM
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Quote:
Originally Posted by dgpilot View Post
Hey guys,

I wish I had done this test sooner (I wouldn't have climbed a fence and nearly broken my ankle retrieving the plane).

This is the RTF version. When I set the easy star on a table and apply power, it rotates to the right. It did this during the first flight, and no matter how much left rudder I input, it still turned right, ending in a clockwise death spiral.

The aileron and rudder are perfectly straight, and I even added a rudder mod. Still, no matter what, it largely favors right turns with the tabletop test. For now I can only do the tabletop test since I'm on crutches for at least a week.

Any ideas?
Are you starting off with WOT, if so cut that back. WOT creates alot of torque. It your ESC programmed correctly? You may not be getting enough power to the motor. If all the above is OK, try a tad of left aileron trim before to launch it and maybe a tad of left rudder. Be sure to verify your center of gravity as well. Nose heavy will make the plane act like your describing.
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Old Sep 12, 2011, 11:54 PM
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Does you rudder have equal left/right travel?
Are the edges of the rudder and elevators cut free?
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Old Sep 13, 2011, 01:03 AM
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Quote:
Originally Posted by dgpilot View Post
What caused the easy star to continuously turn right even with trim set all the way left?
"Trim all the way left"? Is your rudder servo reversed perhaps? When you "trim all the way left", the blade of the rudder should be pointing significantly left when viewed from behind, as if you were in a following plane.

If the rudder is pointing left and yet the plane is still veering to the right constantly, it must have a fairly significant issue.

Did you check the wing stiffness? Has this plane ever been in a crash - even a minor one?

Quote:
Originally Posted by dgpilot View Post
Aileron and tail fin checked many many times and are perfectly straight.
Aileron? An RTF EasyStar doesn't have ailerons unless you've done some mods. Did you mean the elevator perhaps?

Is the horizontal stabiliser level with the main wing?
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Old Sep 13, 2011, 01:47 AM
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Originally Posted by dgpilot View Post
Ok, so table test aside... During my first flight...What caused the easy star to continuously turn right even with trim set all the way left?

And again, rudder looks and responds perfectly when testing on ground. Aileron and tail fin checked many many times and are perfectly straight.
Remove the unnecessary rudder extension and see what happens. Also, post some good quality picture of you EZ.
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Old Sep 13, 2011, 09:09 AM
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dgpilot,
Need a little more info.

1. When you flew your EZ you say it went right with full left trim. Did it respond to left rudder input from your TX?

2. When you say it turns right. Does it stay somewhat flat when it turns or does it bank right?

3. If the plane is only going right with the sticks at the neutral position, then there is not enough trim set. When setting up a planes surfaces we try to get them as straight as possible. But, this is just a starting point. A slight twist in the fuse or a little warp in a wing will make the plane want to do things other than fly straight.

4. Pictures would be great. Show us a pic of how much trim you have set now. Also a couple pics of the plane in general would help allot.

5. You mention ailerons? I take it you added them. This mod is simple but can create forces on the plane which could be creating your problem.

I use my EZ mainly for aerial video and I have no ailerons. The only thing I cannot do with it is a roll. I don't know why everyone wants to put ailerons on this plane. It flies well without them.
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Old Dec 11, 2011, 05:46 PM
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hso4...u obviously should not b a pilot if u are having troubles with the easystar like u say.
i just want to know which way do i turn my easystar motor so mine stops banking left on throttle, it did not b4 but now i hav made the prop much more vertical so it pushes straighter being theoretically faster and less trainer/floaty but it now pulls 2 oneside,
SO, i would guess i need to angle the spinner towards the right of plane? bcoz its a pusher.
im just gunna try and learn myself actually bcoz it is quite a strong symptom of bnking to the right under throttle so it shud b ez to tell wat difference it makes.
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