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Old 04-29-2012, 09:13 PM   #1
JayhawkJake
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Default Fixing a possibly warped wing?

I have a very strange issue with my new Dynamic-S 'hotliner'. It wants to bank right all the time. Takes a significant amount of left trim to fly straight. I've had someone tell me it might be a warped wing, but I don't see any warp. If it is warped, what's the best way to fix it? I guess my point is even if it isn't warped, I might be able to reshape the wing a tiny bit to get it to stop banking. Trim is fine, but I roll slower to the left because there isn't as much deflection remaining that way, and it adds drag which is bad for such a fast plane.

Any help appreciated. This is a very odd and frustrating issue
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Old 04-30-2012, 08:28 AM   #2
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You shouldnt start fixing things until you're certain about whats wrong. You might just be making things worse.

Id start by doing some careful measurements. Set the plane on a large enough, flat table and prop it in position so that trailing edges of the wing tips are exactly the same height above the table top. Then measure how far the leading edges are on each side. Check the trailing edges and leading edges in several places comparing left and right sides.

That will tell you for sure if one wing is warped/twisted in relation to the other side.

Id also check a couple of other things. Support the fuselage in such a way that you can check the lateral (side to side) balance to see if you have a heavy wing on one side.

Also, look down the fuse from the nose to the tail and see if the fuse is bent or the rudder is twisted off to one side.

Lateral balance and any unintentional rudder off sets can also induce a roll.

As far as fixes for a warped wing p it depends on how the wing is built. Is it a built-up balsa wing or glass over foam or wood over foam or hollow carbon fiber or???

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Old 04-30-2012, 07:31 PM   #3
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It's EPO foam with 3 carbon spars.
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Old 04-30-2012, 08:03 PM   #4
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To see if a wing has any warps.
I use an old carpenter's trick (I'm an old carpenter) called winding sticks.

Take some good straight pieces of any thing small and straight. about 3 times the width of what you are checking. (wing or a board) I use a least 3 on each wing panel.

Rubber band them to the bottom of your wing, snug but not to tight so you don't damage any thing.

Now look down the length of your wing from across the room, if the wing or board is straight, the winding sticks will all look like parallel lines, if they don't then some thing is twisted, you can compare left and right sides of a wing even across a dihedral joint very easy this way.

I have reshaped a EPO wing with a hot air gun, I really screwed up a flying wing one time.

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Old 05-12-2012, 07:58 AM   #5
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Word of caution .... some models have washout moulded into the wings ... that is the wing root has greater incidence than the tip. That is effectively a twist along the wing span.

So make sure any alteration you make to wing twist is identical on both left and right wings ...

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Old 11-30-2013, 03:47 PM   #6
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Default Durafly Dynamic S warped wing

I have the same problem. I had my maiden flight with my Dynamic S yesterday, 11-29-13. The control surfaces were all neutralized. Upon launching, it went into a right roll. I had to put in almost full left trim to get the plane to fly straight and level. I landed the plane and noticed an enormous amount of left trim in the ailerons; almost 1/4 inch deflection in the aileron control surfaces. When I got home, I laid the wing on a very flat table, up side up. I could easily see the warp. The right wing was lifting off the table, and it had a clockwise twist in it (when viewed down the wing from the right wing tip). The twist starts at about the last 1/3 of the wing. This wing is a built up wing. You can see the glue down panels on the bottom. I suspect that the wing was not flat during assembly, or, the CF spars are deformed. I've reported this to HK. Not expecting much help there. Does anyone have a suggestion as to how to remove this huge warp? Thanks !!
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Old 11-30-2013, 03:49 PM   #7
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I, and many others, have the same problem. See my posting in this thread. Bob
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Old 12-01-2013, 12:41 AM   #8
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How you fixe it depends on how its built. One person says its foam and another says its built up.

To fix both you start the same way. You need to fix the wing in place on a flat table so that it has opposite twist in it. In other words, twist the wing in the direction it needs to go to fix the problem - but twist it more than is needed. You need to allow for spring back when you remove the weighs holding it in place.

IF its a balsa built up wing, you could try just re-shrinking the covering - while its over twisted - to see if that will fix it. It may not. Especially if the wing has leading edge (D-box) sheeting.

If re-shrinking the covering does not work, then I would remove the covering from the wing first before twisting the wing. Then get the balsa sheeting wet along the entire length of the wing. Then put it on the table, get the correction twist in it by using shims and weights. Over twist it some because it will still spring back. leave it in the twisted position until it is completely dry. Remove from the shims, weights and check. repeat as needed.

IF the wing is a foam wing, AND its sheeted in balsa, then the wetting trick and holding it twisted till it drys may work there too.

IF its just foam with spars, then twisting and weighing it down may work but will likely take much longer. Some gentle heat will help if you can build a hot box to keep it in while its twisted. Sometime just a cardboard box with a 100 watt light bulb in it will help a lot with foam wings. It may take several days though to get it fixed. In some cases I have heard of the fix going away over time on foam wings though.

You just have to try and keep your fingers crossed

I think I need a signature.
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Old 12-01-2013, 01:11 AM   #9
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Default Dynamic S wing warp

Thanks for your reply Larry. The wing is made out of foam and contains 3 CF spars in each wing. By built-up, I meant that there are foam panels on the bottom that are blued down; those panels probably allowed the insertion of the spars; guessing here. Looks like applying modest heat, and trying to force the twist out is a possible answer... need to figure out how to hold the wing in a counter-twist position during the heating and cooling cycles. Again, the twist appears to start at the last 1/3 of the wing. Thanks again, appreciate it.
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Old 12-01-2013, 05:41 AM   #10
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With the foam wing you need to be careful not to put dents or creases in the foam.

I have used buckshot in small sandwich baggies - +- 1.5 to 2 pounds per bag - and use lots and lots of those to hold things down. You can also use rice, sand, etc. The idea is to spread the pressure out evenly over the entire surface so you dont make dents etc.

Then I make up shims to hold the twisted part of the wing at the proper angle and use more baggies to hold the twisted section in place.

Depending on how its twisted, you may need to put some sort of spacer layer under the straight section to raise it off the table. That would be to allow you room to twist the leading or trailing edge 'down' relative to the good part of the wing. If the wing is sitting flat on the table you can only shim things 'up', so the spacer allows you room to shim both ways. You dont want to add a bend in the wing while trying to fix a twist

What ever you use as a spacer needs to be of uniform thickness and evenly support the entire 'good' section of the wing with no hang over anywhere.

Good luck!!

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Old 12-01-2013, 06:43 AM   #11
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Originally Posted by Bob_N7ISU View Post
I have the same problem. I had my maiden flight with my Dynamic S yesterday, 11-29-13. The control surfaces were all neutralized. Upon launching, it went into a right roll. I had to put in almost full left trim to get the plane to fly straight and level. I landed the plane and noticed an enormous amount of left trim in the ailerons; almost 1/4 inch deflection in the aileron control surfaces. When I got home, I laid the wing on a very flat table, up side up. I could easily see the warp. The right wing was lifting off the table, and it had a clockwise twist in it (when viewed down the wing from the right wing tip). The twist starts at about the last 1/3 of the wing. This wing is a built up wing. You can see the glue down panels on the bottom. I suspect that the wing was not flat during assembly, or, the CF spars are deformed. I've reported this to HK. Not expecting much help there. Does anyone have a suggestion as to how to remove this huge warp? Thanks !!
Interesting
IMHO, it might be a good idea to give these foamies (And most of those ARF's) a quick look for warped wings before the maiden flights.

I suspect that any wing that is warped enough to cause flight problems would be obvious by a quick visual check. Just put the model on a table, move perhaps 10 feet in front of the model, and line up your vision directly in front of the nose of the model. Then glance over at the left and right wing tips, and make certain they look OK.

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Old 12-01-2013, 09:29 AM   #12
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My RTF ME109 was warped on both wing and elevators ... both ailerons and elevators had definite banana curves UP to the tips.

I gave a lazy try at straightening .. but gave up in the end and just flew her !

Before flight - I basically eyeballed her from front ... tilting the model to see difference in wing top .. as you tilted - the T/E would appear or disappear ... I then altered ailerons / elevators to best compromise to be similar both sides.

She flew !!

https://www.youtube.com/watch?v=fBK6nXCqAw0

And I was using my 1980's JR Propo Tx 35Mhz with the stock Lanyu Rx ...

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Old 12-03-2013, 05:06 PM   #13
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Default Dynamic S warped wing

Thanks again Larry. Very good suggestions on how to remove warps and twists from foam wings; using bags of shot, rice, etc. combined with shims. I'm taking careful notes here.

And Thanks Dennis, yes, it is important to carefully look over your planes be flying, preflighting. this warp/twist in the right wing was observable when placed on a flat table; but not too terribly obvious. (see photo).

And Thanks Solentlife. I considered doing some bending on the right wing. Right now, I'm jumping through the HK hoops. They requested photos of the packing boxes; that's done, now just waiting.

I'm attaching 3 images here: A straight-on shot, look carefully at the outboard winglets/fins. And two shots showing the laser angles projected on a wall from the outer wings.

Thanks to all for responding,
Bob


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Old 12-03-2013, 06:49 PM   #14
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Originally Posted by Bob_N7ISU View Post
Thanks again Larry. Very good suggestions on how to remove warps and twists from foam wings; using bags of shot, rice, etc. combined with shims. I'm taking careful notes here.

And Thanks Dennis, yes, it is important to carefully look over your planes be flying, preflighting. this warp/twist in the right wing was observable when placed on a flat table; but not too terribly obvious. (see photo).

And Thanks Solentlife. I considered doing some bending on the right wing. Right now, I'm jumping through the HK hoops. They requested photos of the packing boxes; that's done, now just waiting.

I'm attaching 3 images here: A straight-on shot, look carefully at the outboard winglets/fins. And two shots showing the laser angles projected on a wall from the outer wings.

Thanks to all for responding,
Bob
Yeah, you can see the warped wings in your first photo. Good idea on the laser lights!

I've got one of those laser wing alignment units that works well for this sort of thing. The Great Planes model Accupoint is no longer available, but other brands are likely available.

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Old 12-03-2013, 07:24 PM   #15
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Originally Posted by kyleservicetech View Post
Yeah, you can see the warped wings in your first photo. Good idea on the laser lights!

I've got one of those laser wing alignment units that works well for this sort of thing. The Great Planes model Accupoint is no longer available, but other brands are likely available.
Right Dennis, I'm trying to build a case with HK. This is my first experience with a defective wing. I've heard from others that HK is reluctant to help in matters such as mine. Time will tell. Thanks for chiming in.

Bob
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Old 02-27-2014, 06:02 PM   #16
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Most power planes don't roll as well to the opposite direction of the prop rotation. IE: if it spins counterclockwise as looking at it from the front it will have a tendency to roll to the left slower and visa-versa. If it still banks with the power off then it is more then likely a warped wing or stab or a fin off a bit. Check to see if the fin and stab are at 90* to each other. also check the tail feathers to wing alignment too. If the tail is not 90* to the wing it will also bank. Also check the balance form side to side and see if one wing is heavier. On a large heavy power plane it is not as critical but on a glider/hotliner it can be very critical.
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Old 03-03-2014, 08:45 PM   #17
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Was looking at the front view pic you have and it looks like it does have a very slight twist in the right wing if the ailerons are both equal to the trailing edge.You may be able to reform it with a cup of warm water or if your careful with a blow dryer and have a friend help to hold it till it cools.
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Old 03-03-2014, 09:22 PM   #18
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The EPO and other foam aircraft are subject to warping during transport in the car... If there is stress on the wings and the car gets hot inside you can introduce a bend the wing.

Same with wood framed aircraft... heat plus stress can introduce warps.

You can remove the warps from epo by just laying the wings flat on a car bench seat and leaving the car in the sun. It will heat up and the wing will relax and assume its original molded shape.

Wood framed wings covered with heat shrink require careful application of heat and stress to cure any warps introduced by improper storage or transport. Its possible to get the warps out but not as simple as with the foam wings.
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Old 03-03-2014, 10:59 PM   #19
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Is the motor incidence set correctly ? joe
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