wing halves on trainer
 

i have a dragon 40 arf. here is the link to the plane [link=http://www.hpiracing.co.jp/contents_asia/air/kit/dragon40/index.html]dragon 40[/link]
All the guys at the airfield say i should fiber glass the wings together to be safe. and i have decided to do it. but i am not sure how. does anyone have a link to a how to on this subject. or could someone please post the info on how to join the wing halves with fiber glass. they are already epoxyed together. i am not sure if i need a special glue for the fiber glass or what.


thanks in advance

Joshua

RE: wing halves on trainer
 

You can use expoy or CA to fiberglass the joint. Get a piece of 3" or 4" wide fiberglass cloth, available at your LHS.

For CA - pull the tape tight against the wing surface and tack in place. Use thin CA to soak the cloth and let dry. Use thick CA to fill the weave until smooth.

For expoy - use a slower setting mix, like 30 minute. Coat the wing surface with a thin spread of epoxy. Lay the cloth down on that and pull tight. Let dry. Fill the weave with more epoxy. Don't apply too much, it's heavy.

With either method, make sure the weave of the cloth is completely filled.

Dr.1

RE: wing halves on trainer
 

"Finishing" Epoxy is ideal. However it does take 24 hours to cure but gives a nice result.

Followed the link, it looks a great model.

I would consider though, painting the cowl.

Methanol , whether from spilled fuel or just fumes, will attack the FRP cowl and cause it to deteriorate. Painting it, inside and out will alleviate this.

Topflite Lustrkote Cub Yellow will be quite o.k. and match the rest of the model.

If you fly off grass, the wheel spats won't last long. Consider leaving them off if you do.

RE: wing halves on trainer
 

I am a newbie and just built a LT-40. I did not fiberglass the wing halves together. I just used a liberal amount of 30 minute epoxy and the joining bar that came with the kit. Can I expect a problem with the wings on this plane in the future?

RE: wing halves on trainer
 

When I "glass" a wing joint, I start out with a large piece of fibergalss cloth (get it at the hobby shop, it is a lighter weave than what you would find at a hardware.) Lay it over the center of the wing and take a good pen to mark your cuts. I personally mark a triangle starting at the leading edge placing a 1" mark on either side if the center joint. I also ensure that I have that same 2" overlap to go around the front of the leading edge. I then make a mark on the cloth at the the inboard side of the aileron ( the closest point to the fuse. (both ailerons). Also mark the overlap for the training edge. Using a straightedge, I make a line connecting the dots. And cut out the pattern. Do the same thing for the underside of the wing, making another triangle. (Make sure you kow which cuts are for the top and bottom). Now comes the fun part. Starting with the BOTTOM traingle, lay it over the bottom of the wing and line up everything. Find an old credit card witha good straight edge, some disposable gloves, and a good mixing cup. Put on your gloves and Mix some 5 minute epoxy (about two to three ozs. (I like the Devcon twin syringle type - the mix is always right) up and now add some rubbing alcohol (usually two to three capfuls) to your epoxy. Mix completely, your mix should have the consistency of maple syrup and be a milky white. This is called "thinning" the epoxy. Spread the mix onto the prepositioned cloth, and start spreading it with the credit card, starting from the middle (over the joint) and move it to the outside edges. Make sure that you also get it in the weave on the leading and trailing edges and get those edges stuck down. You will see bubbles on some parts of the cloth. As the epoxy starts getting tacky, push those down with the spreading card. You will probably have some fraying edges, but don't worry about those yet, just get everything stuck down. Work quickly, you will only have about 2-3 minutes total. Make sure that you get all the cloth stuck to the balsa. Now mix some more epoxy up on start on the top of the wing doing the same procuedure. The leading and training edges will wrap over the bottom edges. Now you see why you start on the bottom side first. Now you also know why you wore those dispoable gloves, Let dry overnight. You can now start to sand the epoxy "smooth". I start with 100 and end with 200 grit. Those frayed edges can now be cleaned up with an X-acto knife. The sanded epoxy should hold Monokote very well. This method adds very little weight to to plane. It will also ensure an extremely strong wing. Some people might think that this is overkill, but I know from experiance (after breaking wings in half racing Q-500) that this works. Its faster to do the procedure that it was to type it, also experiment a little on a piece of balsa sheeting to figure out your particular mix. The epoxy should be just enough to saturate the weave and stick to the underlining balsa. Move excess epoxy off the weave, always pushing the mixture to the outside edges. Good luck.

RE: wing halves on trainer
 

M. Michael Meyer & sackingsfan,
Most trainers don't use fiberglass tape to join the wing halves together. While it definitely won't hurt to do it, you will be ok if you don't do it. Trainers just don't produce the wing stressing loads that can snap other wings, thus needing the fiberglass to strengthened the wing joint. If you use epoxy to join the wings you will be just fine, IMHO

Hope this helps

Ken

RE: wing halves on trainer
 

Thanks. I really do like this trainer and don't want to see anything happen to it. I know that is dangerous. My instructor told me you should not become too attached to your first plane.:D

RE: wing halves on trainer
 

Michael,
There isn't anything wrong with being attached to your trainer. I've been flying for 9 years and I still have my trainer. Heck, I still take it out to fly it every now and then. That doesn't mean that it hasn't suffered damage, but I have always repaired any damage that happened to it. When it was to the point that covering was coming off of it every flight I recovered it, that was how I learned to cover a plane. Take care of your trainer if you like it, there is no reason why it shouldn't last.

Ken

RE: wing halves on trainer
 

Boy thats no lie. You will crash just a matter of when and how bad. I saw a guy the otherday that has been flying 46 years cartwheel on landing, just matter of time and gravity.

RE: wing halves on trainer
 

RCKen - I agree and disagree. Most trainers do not need the additional "glassing", but I have seen some students over the years that have snapped a wing. I know that my previous post was wordy, but it works and only takes about 15 minutes total to do (to a kit). But, since most trainers today are ARF, doing anything to the wing is tough (I've even put packing tape over the joint to help reenforce the wing - but only on ARFs, not kits) . Mr. Meyer, I concur with what your instructor says - don't fall in love with the plane. If you fly it, one day it meet its demise. But hopefully when that happens, you'll have a couple more to replace it.

RE: wing halves on trainer
 

Well, sometimes it seems that people learning can put their airplane in some really high g maneuvers. We'll call it beginner aerobatics.:D While todays ARF's seem to be really nice, the little sticks that come with the trainers to join the wings are NOT suffecient for the task.

A really easy method for applying fiberglass tape is to use a glue stick to attach the tape to the wing. Start on the top at the trailing edge and work your way forward and over, returning to the trailing edge on the bottom. Use just a small amount of glue. All you want to do is tack the cloth in place.

Once you have that complete, mix a batch of 30 minute epoxy. About 1/2oz or so. You don't want to run out while you're working. Apply the epoxy carefully with a card. It doesn't matter what brand, as long as it's stiff. Work from the inside out and from front to back. If you've applied too much pressure, just trim it at the trailing edge.

RE: wing halves on trainer
 

The Dragon really isn't a trainer -- it is a fairly high performance high-wing sportster (and a yummy bird -- kind of like the Rascal of many years ago). I don't think that any additional work is necessary -- it's already engineered into the airframe.

RE: wing halves on trainer
 

Yep, just noticed this on the web page-

FOR INTERMEDIATE AND ADVANCED FLYERS

Surely they've done the engineering to make a good plane. If you're flying this alone....you ain't a beginner anymore!:D Adding reinforcment will add weight and is bad for flying characteristics of hi-performance airplane like this.

RE: wing halves on trainer
 

The problem with adding fiberglass tape to trainers is that most new fliers don't know that they need to remove the covering to apply the tape. If they put the fiberglass tape over the covering it will be useless because the tape will just pull away with the covering. So if they cut back the covering to apply the tape then they now have another thing to do that they don't have material to do it with, which would be recovering over the area you removed the covering from to apply the fiberglass tape.

As I said above, using a good 30 minute epoxy on the root ribs to glue the wing halves together will make the wing strong enough to stand up to just about anything that they are going to throw at the wing. The epoxy joint is going to be stronger than the wood it's attached too and more than likely the wood will fail before the epoxy joint does.

Hope this helps

Ken

RE: wing halves on trainer
 

Good point about the covering! The better trainers come with a ply wing joiner that should hold up well. I've actually had wings with balsa joiners.[X(] Those always get the fiberglass treatment. It's not for holding the wings together, but to spread the load across a larger surface.

RE: wing halves on trainer
 

I think I'm going to remove the covering and glass my wing. I already had a wing failure and now I am just too shy to do any real amount of loops and rolls. For me glassing the wing will make my plane more enjoyable to fly simply because I won't be waiting for it to fall apart again. I'm heading to the LHS today so I'll get some glass and some covering material.

RE: wing halves on trainer
 

akschu,
I totally understand why you feel the way you do. I saw the thread on your wing failure. But if I remember correctly the wing structure failed, not the joint between the wings. Glassing wouldn't have helped that. Now with that said, I understand about the piece of mind factor too. I say do whatever helps give you piece of mind while flying. While it's not really needed, doing it is just going to make that joint stronger. good luck

Ken