slopeflyer

I ordered a pre-sheeted fiber-lite edge and am wondering if it is possible to weight these back into position.

Thanks

Jake Ruddy

My Feedback: (40)

umm why dont you call them up and ask to get a replacement? That's not exactly what you paid for.

rmh

you can correct warped, sheeted wings
If the wing is merely bowed - weigh can do it .
if it is twisted - cut bottom sheeting corner to corner - a big X cut - then block into position nd slow glue edges back together.
I bet shipping things back n forth is a bit of a problem for you.

DENNIS C

My Feedback: (99)

This should be a interesting thread..........Everybody get ready

slopeflyer

Ready for what?

Ive been weighting for 2 days and as soon as I pull the wings out of the hucks... they are just bowed, not really twisted.

Still havent heard back from fiber lite. I see their out on the website.

Thanks

sweetpea01

My Feedback: (10)

Big thing is you have to bow them back past straight to get them straight.

And that is a guessing game as how far back to bend them

slopeflyer

If I cut the hucks back and inch or so and weighted while attaching le/te would that straighten them out? Its been about 15 years since I built anything and was really looking forward to avoiding these types of issues again

slopeflyer

...

DENNIS C

My Feedback: (99)

Is the bow at the T.E. edge of the wing...or is the whole winged bowed in the center from tip to root.

It's hard to tell by the pictures where you have the ruler

slopeflyer

whole wing on both. The one in the pic is the worst wing and its worse at the te. But if you sight down the wings you can notice it on both the le and te. If I was to glue the edges on with a straight weighted wing do you think it would hold true?

Thanks

DENNIS C

My Feedback: (99)

Nope it sounds like the wings were built on a unlevel table.I think they need to be replaced

dirtybird

My Feedback: (5)

This is caused by unequal shrinkage of the covering (sheeting). I doubt you will be able to correct it

slopeflyer

Thanks

majortom-RCU

My Feedback: (40)

Dirtybird's 'unequal shrinkage' diagnosis is interesting, the implication being the bottom & top skins had different moisture content before they were applied. I suppose that's possible, but it seems to me if that were true the warpage after they equalized to the same moisture content would be an arc of uniform radius, or perhaps a progressive radius because of the taper of the wings. However, what I see in the last photo looks more like a long straight stretch, then an angling off by a degree or so, then a shorter straight stretch out to the tip. So I find the 'crooked table' explanation, or just a sloppy job, more likely.

I appreciate how irksome it is to pay for a 'professionally produced' product, then get something like we see in the photos. Which leads to the more practical question, of the sort builders often face, whether it is easier/quicker to try to repair a crooked wing or build/buy a new one. If you can't come up with a quick and feasible method to get everything straight so it stays straight, then re-build/replace is the alternative. (Assuming you've been burnt by Fiberlite for sure, which I make no judgment on, not knowing them or their story.)

I have fooled around in the past with moistening warped balsa on the concave side of warped pieces before and gotten away with it some times, given up at other times and re-built. If you don't want to spend the money for new wings, then try wiping the concave side with damp sponge (not dripping wet, just damp), then clamp or weight the wings straight, give it a day to dry, and see what you get.

DH's corner-to-corner slicing trick is something that would be fun to try, just for the education of it all. You should, at least in theory, be able to do it; however, I think pulling off a fix of this sort probably requires almost as much building/aligning/re-finishing skill as building new sheeted foam wings from scratch.

When I've made a piece of crap, I usually find the fastest way to get a flyable product is to curse my own carelessness/ignorance/ineptness tonight, then re-build tomorrow, taking care to not overlook steps I probably knew about but tried to shortcut because I thought maybe god does protect fools like me.

If I were prepared to sacrifice the warped wing to science, I would razor saw just the depth of the balsa sheet chord-wise at the high point of the angle, then see how light a touch of compression would straighten the angle out. Maybe it would take a few parallel cuts, but I would be looking for a straightening of the angle with not a lot of force at the wingtip. When you have the right cuts in the right places, then glue the balsa sheet back together. Fortunately the warp looks to be well out toward the wingtip, where the flight stresses would be much less than if it were closer to the root. If this worked, I'd be very pleased with myself, and thank Dick for the good tip.

I've had some very well-built ARFs over the last couple years, and they can be a good value, trading building time for flying. But I've also had plenty of aggravation from substandard product, and I frequently conclude it would have been better to build it myself.

slopeflyer

Thanks for the input!!

I have tried some of your mentioned solutions on other foam wings but found at a later date the wing will assume its natural curve again.

I did ask (email) about their sheeting process and the response was our wings are "cnc'd/sheeted by very picky modellers".

I have made a few attempts at contacting fiber lite with no response. Funny how my order was rushed through. I have been waiting for days for any kind of response. Must be on holidays...

dirtybird

My Feedback: (5)

That sure would be a crooked table.

The strength of the wing is provided by the balsa sheet. Doing this will result in a straight but weak wing

TT2

My Feedback: (13)

This is Tom Taylor, owner of [link=http://www.fiber-lite.com]Fiber-lite Composite Products[/link]. I have just returned from holiday vacation. 'slopeflyer' had emailed us about his bowed wing and I'd like to address this online to discuss with everyone what may have contributed to the warpage and what can be done to correct it.

For starters, I sheeted these particular wings personally...they weren't slapped together by the neighbor kid or some grandmother across the Pacific. Anyone who has seen or flown my planes will attest to their accuracy. However, I don't claim to perfect.

Over the years I've bought several presheeted kits from various manufacturers and have never had a perfect wing. I attributed this to climatic differences or slight inaccuracies during sheeting. I'd correct the problem and move forward. This being said, I've never had a wing that was bowed to the degree that slopeflyer's appears to be.

The following details are provided to help everyone form a more educated opinion on what caused the bowing problem. I'd like to hear those opinions to avoid this problem in the future!

The cores are CNC cut from very low density EPS foam. I personally handle all the programming and cutting of the foam. The same CNC cycle cuts the airfoil and shaves the tops and bottoms of the foam resulting in a perfectly flat surface top and bottom. Let's just take it for granted that the core cutting process didn't contribute to any bowing problem.

The cores are sheeted with hand-picked light (6-8 lb) balsa. Before truing, each sheet is weighed on a gram scale. During the sheet joining the heaviest sheets are used in the spar areas, top and bottom. After the sheets are seam glued, sanded, and cut to size, they are glued onto the foam with polyurethane glue. This method requires the introduction of water to act as a catalyst for the poly glue (alarm bells ringing). The wings are then vacuum bagged on a FLAT table. I used an old-school drafting table top that is within 1/32" of perfectly flat (verified). After the wings cured they were inspected, placed back into the foam shucks and trimmed / edge sanded. Then they're taped up and placed in the shipping box.

My theories on what could have happened are:

1. Moisture. It is quite possible that the wings were still a little damp when they were placed in the shipping box, and they took a 'set' during shipping. Easy to correct.
2. Foam inconsistencies. Low density EPS can vary in density in the same billet (we buy ours in 96"x48"x36" billets). Steam is introduced during the production of EPS so there is typically more moisture in the center of the billets. The density and moisture inconsistencies can result in slight variances in the cores. Unlikely to be that significant...but keep reading.
3. Shuck mixup. There are a few steps that need to be taken before sheeting the foam (gluing in the sub-rib and wing tube socket). During this time the shucks could have been mixed up, and that coupled with the foam inconsistencies may have been a contributing factor. Unlikely to be that significant.
4. Canada is bent.

The fix: Like Dick said, weight and time could correct the problem. If the problem is more pronounced (like it seems to be in this case), you may have to explore other options. I'm thinking that if moisture caused the problem, then moisture can also correct the problem. Try misting the cores with water and weighting them down in the shucks on a FLAT surface for a week or so until they are PERFECTLY DRY! Even the slightest amount of REMAINING moisture may produce unwanted results! Since the EPS foam is an 'open-cell' foam, then it will allow the moisture to evaporate over time. Whenever I'm bending balsa I don't use water...I use ammonia. Yes, it stinks like hell if you're not wearing a respirator. The advantage is that ammonia makes balsa VERY flexible and evaporates quickly. In either case, allowing the balsa to dry COMPLETELY while the wings are weighted down in the shucks is CRITICAL.

I'm sure that the problem can be corrected by applying the solutions I've mentioned. I’m sorry that you have to apply these corrections but I don’t think any amount of precision on this end would allow you to pull a laser-straight wing out of the box…unless the wing was made of different materials.

slopeflyer

So thats it, fix them?

I did not pay for bent wings, a vert fin that has missing chunks of sheeting, and a substandard cowling that has globs of primer missing. If youd like I would exchange these items for proper ones and you can fix them.

My god.

PS you mentioned in a previous email before I had placed the order that your wings were weighted on a slate table. Am I making this up? And yes I have had sheeted wings that have arrived perfectly. From Slovenia via Norway too.

Thanks for the help!

slopeflyer

...

wingburner

My Feedback: (17)

WOW...What incredible amount of hogwash from a manufacturer...There is no way if they were sheeted correctly and allowed to cure properly that they should be warped....Maybe he cures them in the rain....One of the biggest side step explanations of 2007 so far....I know where my money won't be going and where my product advice will be.....

Slopeflyer, it's quite obvious his attitude matches his workmanship..

Good luck with the build.

Flyin Woodbutcher

My Feedback: (3)

not right

TT2

My Feedback: (13)

Everyone: The reason I mentioned applying a rather simple 'fix' is that I thought that it would be easier and faster for slopeflyer to attempt to correct the bowing problem himself than to box up the parts, send them back to the U.S. and wait for replacement parts to arrive. Since this suggestion was not reasonable to him, I will issue a full refund to slopeflyer for the ENTIRE KIT and cover all shipping costs both ways.

Whatever created the bowing problem may remain a mystery (the other wing half was OK???). To avoid any future problems we will simply not offer any pre-sheeted kits. Any references to the availability of pre-sheeted kits will be removed from the website ASAP.

Slopeflyer: I am very sorry about the parts being distorted and the shipping damage of the other kit components. I’d like to apologize to you for any inconvenience. I will email you soon about the return shipping arrangements.

-Tom

Flyin Woodbutcher

My Feedback: (3)

now thats right. Slopeflyer keep the kit and wait for parts. You will be happy with this plane.

Kent

slopeflyer

Thank you.
I will be more than happy to send it back.

TT2

My Feedback: (13)

Glad we could work it out. I will finish this kit for my personal fleet...I need one in Kirby's Red Bull scheme.

-Tom