CafeenMan

This is an article in progress so it isn't complete yet. The first four parts are up now.

Admittedly this is a simpler wing than many, but the fundamentals of how to build a straight, accurate wing apply regardless.

Comments, criticism, etc. are all welcome.

Also, I've been timing each step. The times given are honest and the first three pages were a straight shot. It should give a good indication of where the time is spent and where it isn't (waiting for glue to dry).

I used CA for about two years or so and switched away from it for several reasons. I never had any noticeable health problems, but the cost, the clogged bottles, the really ugly glue joints, the parts glued in crooked, the fact that it's difficult to sand and whatever other problems simply were not offset by how fast it dries. That's just me and I'm not trying to start a glue wars thread. Use what you like. My only point is that I can build pretty darn fast without using the stuff and speed is really it's only selling point.

OK, pages are being uploaded now, but here it is.

http://www.airfieldmodels.com/inform...tion/index.htm

BillHarris

Not a bad article at all, sir.

One comment: it should be _shear_ web, not sheer. As load is applied to the spar, there is differential movement between the upper and lower spar, which puts the material between the spars in _shear_.

The lightest and strongest wings in the universe are winch-launched sailplane wings. They have to withstand winch line forces of hundreds of pounds and use carbon-fiber spars and end-grain balsa shear webs. At the Charles River RC site, look at the construction tips, and especially the Allegro/Apogee construction plans from Dr Mark Drela. On a good winch launch, you can see the wingtips flex 2-3 inches without failing.

http://www.charlesriverrc.org/articles.htm

Your construction methods are excellent, this CRRC info is presented _in addition to_ your ideas.

CafeenMan

You know, FrontPage kept trying to correct my spelling, and I said, "No, FrontPage... you don't know what you're talking about. You're just an html editor. What do you know about construction methods?!?!"

Now I must bow to your and FrontPage's superior knowledge.

Thanks Bill. I'll go back and fix it and look at the link you provided. :thumbup:

CafeenMan

That is a really nice site Bill. I'm going to add it to my links page.

CafeenMan

All that's left to do is shape the wing tips and leading edge. Then it will be ready for the finish. This page details building the ailerons and flaps.

http://www.airfieldmodels.com/inform...ruction/08.htm

Steff

A great article CafeenMan. And thank you for that effort and sharing your experience. I will study it thouroughly and I am sure I can learn a lot. I love building, in fact I believe that no 'buy and fly' plane cambe as rewarding as the one you build and crash yourself.

a word to using CA : I am extremly allergic against that stuff. I can use the odorless CA, but that is expensive. I wanted to use something else, but not white glue because it is heavy. So I tried polyurethane glue. I make the joints a little moist because that glue reacts with moisture. Then I spread the glue on almost all the surface, exept a small area at both sides. For that area I use CA. Put both parts together, use pressure and accelerator and voila! A great, sturdy and lightweight joint. You'll have to put weight anor clamps om it over night just to be sure. That doesn't bother me. It IS messy, I have to admit that. And some people get fooled by the fact that it 'foams' and believe that they can fill gaps like that, which is not true. The joint has to be very tight. An other disadvantage is that it does not last forever on the shelf once it is open. But hey... I'd rather go to Home Depot around the corner to buy glue than order it online or buy it in the next Hobbyshop which is what I have to do with odorless CA.

Steff

CafeenMan

I'm really liking polyurethane, Steff. But if you look at the photos of the construction, you'll notice that there is very little glue evident. That feat would be difficult if not impossible using polyurethane.

What I do use polyurethane for now is laminating. It's great glue as far as ease of use and strength. I live in Florida so I don't have to moisten the wood. The humid climate takes care of that for me.

This page explains how I make my own plywood because I like to work with flat ply instead of warped stuff.

http://www.airfieldmodels.com/inform...ls/plywood.htm

I'm working on a companion article now called (you gotta love my original titles), "How to build a fuselage." Nothing is posted yet, but will be in the next week or so.

BillHarris

I like to use polyurethane glue with foam because it expands into the voids of the foam and increases the effective glue area. I'd eb hesitant to try laminating with it because of the foaming activity, but I'll give it a try.

I also like to use it on D-tube sheeting. It expands and forms a nice filet even if there is a gap. And it stays flexible (brittle breaks).

Enjoying the "how-to" articles!

CafeenMan

Bill - I've only been using the stuff for about eight months, so I can't comment on longevity. If you read the link in my last post you'll see that I laminate under a lot of weight - usually a couple hundred pounds.

I always laminate plywood formers or other plates such as landing gear plates. Smaller pieces of plywood are cut-offs from larger laminated pieces. I just can't bring myself to stick warped plywood into a structure. It takes too much effort to get it to stay straight while the glue dries.

I've also used polyurethane to laminate several firewalls and I've had absolutely no problems with them. Nothing has delaminated or failed. Again, I don't know if it will last for years, but I don't see why it wouldn't. I've really come to trust the stuff. I used to use epoxy, but polyurethane is much faster and easier to use, so I think I'm going to stick with it until I have a reason not to.

Steff

Paul is right. It looks ugly. I use it in areas that one can not see after the plane is covered. It is not difficult to sand, but you will never get it to disappear. I learned to wait a little until the foam builds, which can be between an hour or two, and then clean that of immediately. But I admit that does not always work and still leaves traces.

Cheers

Steff

BillHarris

>you'll see that I laminate under a lot of weight - usually a couple hundred pounds.<

That weight is the key; I'll try it again. I was amazed with how much force the expanding glue could generate when confined.

>It looks ugly. I use it in areas that one can not see after the plane is covered. It is not difficult to sand, but you will never get it to disappear.<

Put some masking tape down at the joint so that any "overflow" goes onto the tape and not the wood/foam. After the glue cures, the tape can be removed with the excess glue.

Steff

Why did I not think of that?


I'll give it a try, Thanks

Cheers

Steff

CafeenMan

This part details how to mount a wing properly:

http://www.airfieldmodels.com/inform...ruction/09.htm

The construction is about 99% complete. This article shows how I built the wing tips. If you scroll to the bottom you can see more or less how the wing will look.

Again, this model is receiving a fiberglass finish that will be top-coated with clear polyurethane. The fiberglass will all but disappear so the finish will look like natural wood. It's going to be a very pretty Stik.

http://www.airfieldmodels.com/inform...ruction/10.htm

The fuselage and fin of My Stik 30 has the finish I am describing:

CafeenMan

Bill - I told you I was going to add a link to your club website, but I completely forgot it until I just took a look at this thread again. I've added it now. Sorry about that.

Mike James

Paul,

Keep up the great work.

It's nice to see that your site is always evolving, and that you are presenting information that many modelers will find to be a handy place to "check in", when facing some of the questions we all have from time to time. We all do things a little differently, and even those who "know" the techniques can benefit from seeing how others do the same job.

Also, it's nice to see an RC site that is readable. I still occasionally stumble across an RC site that looks like the example in the image, and get turned off immediately, because it causes so much eye strain.

Don't stop!

CafeenMan

Mike - Thanks again for your kind words. I know what you mean about those sites. It's too bad when a site has really good content but is painful to look at. Sometimes I'll stick around but normally, like you, I just leave.

I still have a lot to learn. My site has gone through more revisions than I can count, because I started out knowing nothing about web design and made it up as I went along.

Anyway, the words of encouragement that I receive are pretty much what keep me working at it.

Thanks again,

- Paul