strattac

My Feedback: (9)

My 62" Osiris flys level and straight only with a noticeable amount of left aileron trim and right rudder trim. Looks like the fiddler crab. Any suggestions would be appreciated.

ytell

I'd suggest heavy wing check first

Yoav

strattac

My Feedback: (9)

Thanks ytell, I weighed the wings. The right wing is a bit heavier than the left. Right wing weighs 270g and the left weighs 263g. I'm thinking adding weight near the servo area??? Gets me close to the center of the wing. You guys think 7 grams is enough to cause the problem?

woodie

I don't know how much is 'noticeable trim', but if it is anything more than about 1/32", I would look for a warped wing first. Also check to make sure your elevators are aligned perfectly. Second issue, needing right rudder trim sounds like you might need a little more right thrust.

Woodie

Silent-AV8R

My elevator halves were off. I had to cut them and get them level. Until I did that I had to carry more trim that I was happy doing.

PatternFlyer

My Feedback: (182)

Mine also does carry left aileron trim. Did you check the incidence of the wing panels?
Mine has different incidences for wing panels. Haven't tried adding plywood rings for incidences yet.
Mine also flys with tail down, and up elevator trim. A little tail heavy CG, but noticible.

When I worked on the one for my friend, we went for dual elevator servos. Checked the horizontal stab incidence also.
If you push the horizontal stab all the way forward, it will have positive stab incidence of more than 0.5 degrees.
We pulled the H-stab backward to set the incidence to 0. Much better than mine.
It also has left aileron trim.
Checked the wing panel incidence. it was about 0.3 degrees off.

Weight difference doesn't matter much on this plane unless it is a lot. Mine has heavier left wing panel.
Plane will dvelop slop in the alignment hole in a few months. My left wing moves about 1/16" on trailing edge.
Since I started flying 2m, I haven't flown it much. I am trying to set it up again to fly slower and similar to my Abbra.

RC11

My Feedback: (7)

Same problem. Up elevator trim and left aileron. Added wing adjusters and fixed a lot of the problem. Pulled the one wing up as far as the fuse would allow and went with it. Got all the aileron trim out and much of the up elevator.

Hope this is helpful,

RC

PatternFlyer

My Feedback: (182)

RC11,

Can you post a few pictures of wing adjuster installation on your?
Which adjusters did you use? All 4 or just two in front or back?

Thanks,

IP

RC11

My Feedback: (7)

I don't have access to the camera.
It was a simple install. I simply enlarged the existing guide pin holes in the fuse to allow the incidence change. Then I installed some Gators in the fuse in the teardrop shaped hole just ahead of the rear pin. Carefully fill the corresponding hole in the wing with some ply and drill a hole to accept the adjuster pin.
The fuse doesn't allow much movement as the wing actually fits into the fuse but their was enough to get rid of all the aileron trim and much of the up elevator trim.
The plane flies much better now even though it still has some up elevator in it.

Hope this is helpful,

Rick

houckj

I am a Sportsman competitor in Pattern and learning a lot.  My (purchased used) Osiris has several of the problems described above and I am trying to figure them out. 

PatternFlyer

My Feedback: (182)

houckj,

Gator or World Model adjusters should work fine. World Model's adjusters are cheaper I believe.
You need to get a good incidence meter.

Robart (not very accurate and doesn't align well),
Hangar 9 works ok but need to make sure to remove the slop on the rail and meter mounting. I've seen people using digital meters of different kind too.
Laser type requires reference surface like wall on the back. Not bad, but requires space.

I use two Hangar 9 nowadays. both have different angle after calibration. Choose one to be a reference and mark the other one the difference. Reason using two is that I don't have a whole lot of space to work on the plane and a firm way to hold/lock the fuse without movement. So, I put both in one wing panel and move one of them around while check the other one to stay on same.

I believe many of those who built Osiris (including myself) followed the instruction to glue the H.Stab, will have up trim.

I was told factory slot for the stab should have correct incidence set, but I don't think it is right. I couldn't move my stab forward or backward as it was really tight. 2nd one wasn't that tight at all.

Also, alignment with wing tube wasn't a good idea. wind didn't have correct angle on 2nd one. I checked twice with wing panels and with wing tube.

Try to describe your problem as much as possible.
Do you have mix set up for the elevator and ailerons on rudder?

Adding adjust is a good idea, but make sure your wing can move at least 0.2 degrees without the wing hold down screw, pushed in all the way.

I am waiting to see how 2m Osiris will look "inside". Picture of outside doesn't count. I will only decide after looking at the inside.

strattac

My Feedback: (9)

Thanks for the input, I did add weight to the light wing and both wings are now at 270g but it made no difference, still left aileron trim of about 3/16 to 1/4". Elevator halves appear to be even and I can't notice any warp in the wing panels. I will check the wing incidence and see if adjusters are needed. Thanks again for the help.

ytell

Can you tell if inverted level flight leads to the same result? can you fly upright and inverted hands off with the same trim?

strattac

My Feedback: (9)

inverted flight is pretty normal just requiring a little down elevator but no additional trim changes.

ytell

can you post a photo from the rear so we could see how parallel is the horizontal stab with the wing and also the ailerons in neutral position (trimmed)?

PatternFlyer

My Feedback: (182)

3/16 to 1/4" ?? that is a whole lot.
if you can get a piece of blue or pink foam about an inch thick, and longer than the wing root rib, try putting the wing panels side by side (top of wing panels facing each other) to check the straight line on both comparing each other.

that much trim always affect something.

Like ytell said, if you can take a few pictures of fully assembled plane from rear, we should be able to tell you more about it.

Any other Pattern pilots around you?

strattac

My Feedback: (9)

[img][/img] Here's a picture from the back, looks straight to me.

RCBruski65

My Feedback: (44)

It looks like the right elevator is higher.

Dave Harmon

+1 on that.
The right elevator is definately higher than the left.
If it has a tip on the stab just ignore it and look at the center part of the elevators.
Also...get directly behind the airplane...the pix is off center but the right elevator is so far off it can be easily seen.

strattac

My Feedback: (9)

Looking at the first picture the elevator halves do appear off, but here are a few more pictures. ???

ytell

As far as I can tell from the photos:

1) There is no rudder trim. Or is there? Was your model ON when the pic was taken?
2) The right aileron trim is noticeable only for the inner side of the ailerons. the outer seems perfectly align with the wings trailing edge. Is this correct?

Just to complete the picture, how does it fly? Can you point any bad habit or flying quality that can be attributed to the left aileron trim?

nonstoprc

My Feedback: (90)

Sounds like the left wing panel generates more lift hence the need for left aileron trim.

Is wing incident the same for both panels?

Is the left wing "ahead" of the right (i.e., the distance between the tip of the left panel to the tail end of the fuse center is more than that of the right)?

PatternFlyer

My Feedback: (182)

Your elevator halves not aligned. Left elevator is lower than right elevator. It will cause roll to right. Thus, left aileron trim.

Fix the elevator alignment first.

Two ways to align.

First method.
Going Dual Elevator servos. if you can't find the stock elevator control horn, cut it off. Cut out the elevaotrs (CA hinges?). harden the right elevator on the control horn location (may want to peel off a little of covering to add epoxy). It has slot already cut out.
Make both elevator halves even thickness on control horn location. Drill and use Dubro 493 or something similar. Don't use reversing Y. USE separate channel to use programmable mix or any other dual elevator function on the radio.
Use robart type hinges or regular plastic hinges if you have hinge slot machine. CA hinge is really hard to remove. I used Robart hinges.

The other way.
If you can, cut the center of the elevator joiner, add two 1mm thick x 5 or 6mm width carbon strips on top and bottom with epoxy while elevator halves aligned. Since the stock joiner will stay in angle, you may want to shim between the thicker strips on top and bottom.