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Old Aug 13, 2009, 06:47 PM
RIP MC
fnnwizard's Avatar
United States, CA, Midway City
Joined Dec 2003
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Todd, will it bank left at all speeds without the correction? And with the correction on the tip, will it stay level at all speeds too or does it bank right at higher speeds?

It could be there's a slight twist or one of the control surface in the wing is slightly twisted. Use a few straight dowels attached with rubber bands to bottom of wing chordwise to check for twists. Of course you'll be in reflex .

Are the wings balanced? I put my wings together and run a string through the bolt holes, hung upsidedown to see if they balance.

Other things to look for:

1. H Stab level with wings if not the plane will want to bank to the higher stab's side.
2. Boom not crooked
3. rudder inline with fuse as looked from both top and bottom.
4. wing tips measure equal distance to say... back of rudder
5. twist in the stabs

if 12345 are all ok, my money is that the problem is in the wing.
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Last edited by fnnwizard; Aug 13, 2009 at 07:54 PM.
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Old Aug 13, 2009, 07:53 PM
DS= -$ & :-)
Ezza's Avatar
Byron Bay, Australia
Joined Feb 2006
3,089 Posts
Quote:
Originally Posted by fnnwizard
Are the wings balanced? I put my wings together and run a string through the bolt holes, hung upsidedown to see if they balance.
I'll bet that is the problem. I hated doing it, but I had to add about 7grams to one side to get mine to balance. I put it next to the aileron servo. It would have been better to get the weight further out but everything was hooked up and I was lazy.

Eric
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Old Aug 13, 2009, 07:56 PM
Detail Freak
target's Avatar
Harbor City, CA
Joined Oct 2003
21,771 Posts
I'm "banking" on slop in a flap servo or linkage.

BTW, just because the tip panels weigh the same, doesn't mean the weight in the panels is distributed equally. One panel could have a heavier root, and lighter tip, and the other a heavier tip, lighter root, but they would weigh the same.
Not certain that this will make the plane roll, but I would assume it would effect it adversely.

T
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Last edited by target; Aug 14, 2009 at 11:30 AM.
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Old Aug 13, 2009, 07:57 PM
RIP MC
fnnwizard's Avatar
United States, CA, Midway City
Joined Dec 2003
3,346 Posts
Quote:
Originally Posted by target
BTW, just because the tip panels weigh the same, doesn't mean the weight in the panels is distributed equally. One panel could have a heavier root, and lighter tip, and the other a heavier tip, lighter root, but they would weigh the same.
Not certain that this will make the plane roll, but I would assume it would effect it adversely.

T
Yep, very true. Thats why it is a good idea to put wings together. A tip is I usually do this when I first get the wing before the build. Then if there is a discrepancy, I note which side to be "light" on and which side to be "heavy" on. DOing this with the X tips, I needed no monokote trim to balance it out .
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Last edited by fnnwizard; Aug 13, 2009 at 08:02 PM.
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Old Aug 13, 2009, 08:28 PM
Win=span\massXpractice+lu ck
webbsolution's Avatar
Joined Jul 2007
3,088 Posts
I tried

It looked like the weather here was going to hold and as I got to the field a large black cloud started heading right for us....with lightning in the forcast I decided to wait....of course now its pouring....

I don't think I will be able to get the 3.8 wing dialed in before this weekends contest
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Old Aug 13, 2009, 10:59 PM
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What I want to know about the left tip camber question is has it always been this way and you just noticed it. or did the plane used to fly straight with all surfaces even and now it doesn't? I don't think that it's that unusual for one of the ailerons to be off just a hair when the plane gets trimmed out. In fact very few of my moldies have been absolutely true right of the bench. If you are going to balance the wing it is better to balance the entire wing side to side while on the fuselage rather than just adding weigh to the lighter tip to make it match the weight of the other tip.

Clay
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Last edited by ClayH; Aug 14, 2009 at 12:15 PM.
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Old Aug 14, 2009, 12:42 AM
Hot Dawg Glider Pilot
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United States, TX, Weatherford
Joined Nov 2002
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Also check your fuselage. If it's slightly warped, it will cause the model to fly in a slight yaw. You may be countering that with that bit of camber.

Just a thought from an old wood wanger...

Jack
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Old Aug 14, 2009, 06:45 AM
WINS - Winch In Nose Sailplane
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USA, NH
Joined Mar 2008
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edited out
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Old Aug 14, 2009, 11:43 AM
agony sweetns the victory
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Any Flying Field Across America
Joined Jul 2005
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Thanks guys for the suggestions I'll start checking them out. Yes, Clay it has always had this "problem" which like I said in my first post is not really a problem just an annoyance and cause for a little additional drag.
Todd
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Old Aug 14, 2009, 10:05 PM
Win=span\massXpractice+lu ck
webbsolution's Avatar
Joined Jul 2007
3,088 Posts
Quote:
Originally Posted by fnnwizard
Dave, check the horn to clevis fit and see if it is or isn't binding. The stock clevises that come with the X only fits the horns that come with the X. You can't mix it with say MpJet horns as the hole is just slightly smaller than the clevise's pin. Seems the pins are just slightly bigger than the standard .55mm.

Also, Mike Lee had suggested in an earlier post to free up the hinge by running a flathead screw driver along the hingeline inside the wiper. I wouldn't think that is what's causing centering problem, but it will make your servo much happier when deploying full flaps.

Don't know if you are or not, but use 5 cell battery.

You'll love the extra 12"

Well I have a contest to attend tomorrow so I could not wait for any better weather for a remaiden with the 3.8 tips. IT has been rainign for a couple days over here and its pretty cold. The sky is grey rolling clouds on top of more grey rolling clouds. Wind was 12KmH from the south.

I was not really expecting much and to be honest the 3.5 was flying so well for me that I was wondering why I put out the cash for these tips when I could have likely picked up a used second plane.

I decided to stick the larger stab on since it was not a weight penalty as compared to the standard. I gave it a toss and it flew as I thought it might but the float factor was immediately evident. I wanted to check the flap to elevator compensation since there was more stab area now and it seemed to be about the same as it was before. So I tossed it harder and this time banked it around and flew it right into my hand. One click of down was required thats about it.

The next three bungee launches were so totally suprising. With the extra 12" it was like a kite on the line and I got 3/4 of a winch launch without any effort. I played around and noticed that I could float and maintain in buffeted air coming off the trees at the far end of my field. Then I hit a little buble and dam if that thing did not climb up like mad on a cold day! I came in after counting 9 beeps on the radio tmier and landed one inch to right of my chute. The next thee flights were 10 minutes an bang on the landing zone.

I love this new wing!
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Old Aug 15, 2009, 07:09 AM
F3J Nut
London UK
Joined Jul 2005
44 Posts
Waiting confirmation of results. Primoz Rizner flying Xplorer's has just won the F3J European Championships...
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Old Aug 15, 2009, 11:19 AM
Daryl Perkins's Avatar
United States, VA, Falls Church
Joined Mar 2007
1,371 Posts
Dave - I've been goin on and on about it for years... span is a beautiful thing...

Have fun

D
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Old Aug 15, 2009, 11:44 AM
Registered User
Encinitas, CA
Joined Jun 2007
176 Posts
I actually like the 3.8 better than the 3.5. The only big question I have is whether or not the wings will hold on more than 10mph wind and/or 10-20oz of ballast. If it does not break, then there is no doubt in my mind that the bigger plane is the way to go in under 15-20mph winds.
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Old Aug 15, 2009, 07:20 PM
4 wheels move a body; 2 a soul
Saratoga, Ca
Joined Feb 2004
1,462 Posts
Quote:
Originally Posted by marios
I actually like the 3.8 better than the 3.5. The only big question I have is whether or not the wings will hold on more than 10mph wind and/or 10-20oz of ballast. If it does not break, then there is no doubt in my mind that the bigger plane is the way to go in under 15-20mph winds.
How does the 3.8 EX respond to reflex? Do the larger wings seem weak, as I was wondering about your concern of them holding up in a little wind? I would think they should be fine in 10-15 winds. I agree with the span thing, I am really liking my ZenithXXL with the larger span. Also, have flown it on some windy days and have yet to even consider ballasting, put it in reflex/speed and it just goes, with little loss of altitude. When I get an Explorer may go with the larger span and hope it will respond well to reflex also.
Walter
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Old Aug 16, 2009, 07:49 PM
Registered User
Sarasota, FL
Joined Jan 2006
190 Posts
Joiner Box Depths

I'm beginning to put my 3.5m Xplorer together. This is not the carbon version. I measured the joiner box depths and the joiner rods. The boxes in the main panel are 1" longer than the joiner and the boxes in the wing tips are 1 1/8" longer than the joiner. In other words the joiners do not go all the way into the boxes and abut the spar in any of the panels. There is at least 1" on each side of the joiners that is hollow.

Is this the reason the main panels have failed? I'm thinking of using vertical grain balsa capped with carbon fiber on all four sides to fill the open void in the spar boxes. This would fill the 1" voids in each panel and I think would prevent any spar failure or buckling.

Maybe I'm just paranoid about this but any comments, suggestions, or thoughts on this would be appreciated.

Phil
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