pipercub6

My Feedback: (16)

I am currently building a Desparado 3000 (Simitar Style) plane
and am ready to start work in the wings. The original plans are to cover it with 1/64th ply which is way too expensive for my
budget. My intentions are to cover it with 1/16 balsa and then use a fabric covering for strength.

Also has anyone every built one of these and made it a two piece wing? I would really like to go that way if possible due to the span being 84 inches.

If anyone has any info that would help it would be greatly appreciated.

Thanks, Pipercub6

soarrich

My Feedback: (98)

You have a few of options;

You can use posterboard it makes nice wing skins.

You can go to a good hardware store and get paperbacked vineir, similar in thickness and streght to 1/64 ply. It comes in sheets about 18" x 7' cost me $40 2 or 3 years ago.

You could fiberglass the wings. You don't have to vacuum bag them, but that's an option if you know how.



No, but it should be easy to do. Make two 1/8" ply center ribs, then to sub ribs about a foot out, drill out a hole for a wing tube like the 1/4 scale guys use and build.

pipercub6

My Feedback: (16)

Hi Rich,

Thanks for the ideas! I'm going to shop around for posterboard.
Would it be better to glue it on with an elmer's type paper glue or should I use something like core bond from Sig. Also does posterboard take covering well. Which would be better to use, monokote or fabric, or some type of sealer and paint.

I'm also going with your info on the two piece wing. Do you think I would be able to drill it ok with a forester bid with an extension?
In the mean time I'll experiment.

Thanks, pipercub6

pipercub6

My Feedback: (16)

Hi Rich,

Thanks for the ideas! I'm going to shop around for posterboard.
Would it be better to glue it on with an elmer's type paper glue or should I use something like core bond from Sig. Also does posterboard take covering well. Which would be better to use, monokote or fabric, or some type of sealer and paint.

I'm also going with your info on the two piece wing. Do you think I would be able to drill it ok with a forester bid with an extension?
In the mean time I'll experiment.

Thanks, pipercub6

JAG Aircraft

My Feedback: (3)

Dave Browns Sorghum Contact Adhesive works good on ply-balsa or poster paper i have used this on lots of planes. 1/16 balsa works good and monokote is find over it. It is bugget friendly just use a staight edge and cut the edge straight butt them together with med c/a on a flat surface. The back off the monokote on the surface will kept them from glueing to your surface. You can take two liteply strips and a Aluminum all 1/8 and make a wing jointer loff set them in each wing so they bypass on the side of your sides put two 6/32 screws in them and your wing will be removable and strong i would put two of these in that size wing.


Good luck James A Guinn

Ed Smith

Be carefull with poster board. Just finger pressure will dent the wing very easily. Balsa or the veneer as was suggested will be far more suitable.

Ed S

soarrich

My Feedback: (98)

I'm cheap, I go to HomeDepot and get Wilsonart waterbased contact cement, (something like core bond from Sig), I think it's name is H2O, ~$5 a quart. On white foam it may take 3~4 heavy coats, 2 on the poster board. You want it to have a nice sheen when dry. You'll use about $1 worth on a big wing like you're building. The glue is used to hold Formica to counter tops. While you're there get a "J" roller too, you get a much better bond if you roll it.

I don't know if you know this, but Wing Manufacturing used to make foam wing replacement wings for most kits, they may still, their wing kits used poster board for skinning.





Yes, if you use real thin stuff you have to be careful not to over heat it, but you should be using the heavier posterboard, and that you can treat just like it was balsa. I would use either EconoKote or Ultracoat with the iron set as low as possible. I like to use stuff like Sig Stix or the stuff in the green and white can by Red Baron, (I think), and cut it with MEK 3 to 1, as it comes from the can it's waaaaay too thick.

You can paint it with a house later paint if you like.



NO, the way to do it is take two pieces of 1/8" ply, lightly stick them together stacked on one another and cut the hole. You'll want to make the hole lower in the next set, this will give you your dihedral while still using a straight wing rod. The lower the hole in the outboard false rib, (That's what they're called.), the more dihedral you'll have, you have to figure it out. I use a jigsaw to cut the hole, but if you have a drill that will cut it cleanly use it.

If your wing core is 3" thick and has a 15" chord you'll need your four pieces to be a least that big.

I assume you're cutting your own cores, so you must have a foam cutting bow. 12" in from the center setup to vertical templates, two carpenter squares, at the front and back of the core. If the wing core is up 1/2" from workbench, i.e. the foam bed is 1/2 thick under the thickness part of the core, put a 1/2" thick stopper on the workbench, at both vertical templates. A couple of decks of playing cards, or 1/2" thick wood will work. Now remove the top bed, leaving the core and the bottom bed. Take the hot bow and go down the vertical templates to the stopper, then pull the bow back up keeping it against the vertical template, if you have helper when you get to the stopper have him pull the outer part of the core away from the bow.

Now your wing is in four parts, two inner sections 12" long each, and the outer panels. You want to glue the false ribs to the 12" long sections. The two center false ribs should be the ones with the whole the highest, be careful to keep the holes the same distance back from the leading edge. Once you have the outer false rib on you can use the wing tube that holds the wing rod a whole cutter. Make little cuts in the wing tube end, stick it through the center false rib's whole and drill your way to the outer false rib, aiming at the whole. You'll miss it, no problem, now do the same from the outer false rib toward the inner, now you should be able to get the wing tube to go through both false ribs. Do the same on the other inner core. You should now be able to put the wing rod in and have a nice 24" wing. If you haven't already cut the ply to match the foam its glues to, put it all back in the foamcore beds and glue the outer sections back on. It should now look just like a foam core you started with, but with the ribs in place. Now you can sheet your wing.

Before I sheet the wing I run all the servo wires in by cutting little grooves laying in the wire, then filling the grooves with one step spackle.

pipercub6

My Feedback: (16)

Ed & Rich,

Thanks for the great info, I didn't expect so much info and good building tips, When I'm done I'll try to get a pic of it on. I'm shooting for a 12 to 13 lb plane and for power an ST 2000. With over 1800 + sq in of wing area (it has a 22 in root cord) it should be a bullet at full throttle.

Thanks again, Cliff

Scott Smith

My Feedback: (4)

Forstner bit works great with the blocks as described by ptxman in thread http://www.rcuniverse.com/showthread...844&forumid=58

I built the jig and used an inexpensive piece of rolled steel as the extension (3/8 ID received the forstner bit nicely). Had some run-out in the extension so I used a 7/8" bit for the 15/16" tube. Fit and alignment came out perfect!!

pipercub6

My Feedback: (16)

Thanks for tips Scott!!

Pipercub6

pjwright

I read recently that aliphatic resin glue (Titebond, etc.) works best for wing sheeting if used like contact cement -- applied to both the sheeting and the core, then allowed to dry before covering.
Clamp the balsa sheeting to the trailing edge, and apply heat with a travel iron (don't forget the sock) -- working toward the leading edge.
Haven't tried it yet, but the author says that the heat activates the glue resin, creating a far stronger bond than if applied wet and weighted in the core chucks.
;-)

pipercub6

My Feedback: (16)

Thanks PJ,

I had a friend in the military that showed me how to do that using obiechi veneer. It does work really well. He used a full sized iron and a little steam with it. Another thing he also did was thin the glue and color it with food coloring so he could tell whether he covered the foam completely.


Thanks again, pipercub6

klhoard

My Feedback: (10)

I use polyurethane glue to sheet the wings on my pattern airplanes. The glue foams up as it cures and will penetrate the wing core insuring that you don't have any gaps.
I also don't bother edge gluing the balsa sheeting with this glue. If you true edges of the balsa sheets then tape them together on a flat surface, they will slightly pinch together when you put the sheeting on the wing. This saves a real pain in the butt step and eliminates any glue seams on your finished wing.

JAG Aircraft

My Feedback: (3)

How much weight do you put on these? Do you put them back in there shuck to do this? This is ProBond glue your using isn't?

James

klhoard

My Feedback: (10)

You have to use the shucks to make the wings.
I make a "sandwich" of the bottom shuck, thin plastic (to protect shuck in case any poly glue escapes), balsa sheeting, foam core, balsa sheeting, thin plastic, and the top shuck. On top of this I put a 3/4" plywood board and clamp it to my flat building surface with a little pressure to compress the whole thing. Keep looking at the core until the balsa is in contact with the foam and you'll know how much to compress the whole thing.
I then go around the board and measure from the table to the plywood board to ensure that there is an equal distance all around, thus giving me consistent pressure to the whole wing core.
I let the whole thing cure overnight, but the instructions with the glue says it cures in less time. Some of the glue may foam out the root or tip of the core you you can test it to see if the core is ready.

Keith

soarrich

My Feedback: (98)

If you do this it may help to wipe the core with a damp sponge right before you put it all together. I haven't used poly to put sheeting on cores, but I have put landing gear blocks with it. My glue states that water is what kicks the glue.

klhoard

My Feedback: (10)

I would avoid wiping the core with water for a couple reasons. I know what the instructions say, but I have only managed to make a mess using poly glue by combining it with water. Normally, the natural moisture in the air and wood will be enough to cause the glue to cure.
First, when you spread the poly glue around, the humidity in the air will begin the curing process - you will notice that the glue will begin to turn a lighter color and foam slightly. If you wipe the core with water, this process may speed up too quickly and not give you enough time to work.
Second, if you wipe the core with water, you will be trapping moisture into the wing that has to come out over time. I'm not sure if that would be enough to warp the wing once the glue cures and expands into the foam, but it could cause problems down the road with the covering.

klhoard

My Feedback: (10)

Another trick with this glue is to heat it like epoxy. It will turn very liquid and flow like water. However, the glue will begin to cure very quickly so make sure that the glue doesn't have far to go once you begin.
I accidentally cracked the stab on my pattern plane while painting it, so I had a buddy hold the crack open while I applied a bead of poly glue to the crack. I then used my heat gun, holding it about a foot away then slowing bringing it closer until the glue began to turn liquid. It then flowed nicely into the crack and began to turn lighter color and foam. We then closed the crack and held it closed with masking tape. After it cured, sanded it even and it was just as strong as the other side.

klhoard

My Feedback: (10)

BTW - don't try the heating trick when making wing cores. . . the glue will cure too quickly. . . .

JAG Aircraft

My Feedback: (3)

Thanks: klhoard
I like the clamp deal, a guy told me about this last year and i havn't try it. He said to put two hundred pounds on it but the clamp will work better i will built me a table just for doing this. I do lots of foam wings, and i like the tape without glue to. I have been doing that but with glue.
Thanks Again
James

klhoard

My Feedback: (10)

Instead of building a table just for wings, I have thought about taking two 3/4" plywood boards and drilling holes thru both of them near the corners. Then take either long carriage bolts (about 6" should do) or threaded rod thru the holes with wing nuts on the top.
You can then sandwich the cores between the plywood sheets, screw down the wing nuts for compression, and measure around the edges to ensure consistent pressure all around.
Also, I don't see why you couldn't add a third plywood board and additional wing nuts so you can do a set of two wings at the same time. Clamp down the first two boards with a core in between, then put the next wing core on top, then clamp down the third board on top of that. I just don't make enough wings to justify this effort, but perhaps you do. . . .
I am also sure you will like not having to edge glue the sheeting. I just made a set of wings for an LA-2 and am very happy with the results. You truly cannot tell where the sheets butt together (except visually) since there are no glue lines. The key is to make sure the sheets are absolutely true to each other, and that they pinch together when applied to the core so no glue will squeeze out during the curing process. Even if some does, the Poly glue will sand easily.

JAG Aircraft

My Feedback: (3)

Kieth Thats a great ideal the three sheets will work great, i will have to use three alltread on each side some of my wings are 40" i will make one of these next week i have a set of wings to sheet then. This site is great we can all give eachother ideals with so many on it there is nothing we can"t get to work and save time and have a better finished job.

Thanks again
James Guinn

klhoard

My Feedback: (10)

Glad to help!! Post a couple pictures when you get it finished.