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-   -   coroplast build (http://www.Wattflyer.com/forums/showthread.php?t=72842)

hayofstacks 12-22-2013 04:41 PM

coroplast build
 
so, one of the guys me and my dad fly with had some family move in. he lost his building space and garage. he brought over a bunch of things that we are keeping for him. he wants to get us involved in spad and combat style airplanes. he brought over some 6mm,4mm and 2mm coroplast and wants us to all start building planes with it. he also brought us a bunch of meter sticks, wooden dowels, and a few flat bats.

what I have been visualizing is a simple build. I'm thinking I was to use all 6mm coroplast (we have tons of 6mm compared to the other sizes, and we dumpster dove it, so I consider it to be free), and powered by a heads up 480 plus. size and weight will tell us if its going to be 3 or 4 cells, and hopefully not under powered.

looking at making a triangle shaped fuse for weight, simplicity, and strength. this is going to be more of a test bed for construction techniques more then a well thought out flyer. the wing I want to build out of either 6mm coroplast(heavy I know) or 4mm. I haven't decided on what style of wing, but it will have a meter stick spar, possibly cut down.

from what I've seen and learned from scraps, its very easy to fold, cut and shape. I think a fully symmetrical wing would be easiest to build. cut out two flutes up front, glue it, glue trailing edge, and then after glue sets, slide the yardstick in where you want it, clamp the outside to keep it in place and then drip ca down the stick to keep it from moving.

I also picture a v-tail, and no aleroins, just to keep things super simple and a bit lighter.

any suggestions? this will be my first one off build. shooting for 40" or so wing span, and want it in the 2-3lb range.

fhhuber 12-22-2013 05:12 PM

No ailerons = you need significant dihedral making the wing harder to build. Its easier to put on the ailerons.

The main reason to use 2mm skins on the wings is to keep weight down.

hayofstacks 12-22-2013 05:24 PM

2mm is $15 a sheet. once I get something I'm happy with, ill build it out of 2mm.

even with a v-tail you need aleroins? id think the v-tail would still make it controllable. adding aleroins wouldn't be that hard or the end of the world though.

fhhuber 12-22-2013 06:55 PM

6mm X 2 layers for the wing would be so heavy you will never be happy.

I used to sell kits for coroplast combat models. Saving weight is very important in order to get acceptable performance.

hayofstacks 12-22-2013 08:39 PM

I just weighed some 6mm stuff. your right. I think a 40" wingspan of 6mm coroplast would weigh about 30oz just for the wing!

the 4mm stuff will weigh a bit over half that. I guess I'm going to cut up some 4mm and see what I can come up with. I had no idea this stuff could be.that heavy.

CHELLIE 12-22-2013 08:48 PM

Here are some tips for building with Corrugated plastic

http://homepages.sover.net/~badmojo/pages/aircore.html

http://www.sover.net/%7Ebadmojo/imag...oCap-wing6.jpg

CHELLIE 12-22-2013 09:02 PM

http://www.comp.lancs.ac.uk/~andy/rc/

hayofstacks 12-24-2013 09:17 AM

thank you very much for the links.

after playing with the 6mm stuff, I simply can't believe how heavy it is. I made a 4ft long fuse to add a bunch of nose weight and keep cg in check, and its just too heavy. I was very surprised at how strong it was though. I let my 2 kids play with it. they actually set it up on a chair and were using it as a teeter totter , both sitting on each end.

I'm gonna start work on a shorter and smaller fuse out of the 4mm stuff and see what I come up with. I'm trying to plan around a 480-.10 sized electric on either a 3000mah 3 cell, or a 2200mah 4 cell. I'm trying to get it in the park flyer class, but we will have 380-450 watts and about 55oz of thrust to play with it

I'm hoping to get it in the 30-40oz all up weight, but I think it will still fly okay in the 50-60oz range. once I get a basic design down and get good at building with it, I plan to use 2mm where I can and lighten everything up overall. I may even step up motor size if I need more nose weight. I'm also starting to think a tapered 4 sided box fuse would be lighter with slightly less materials then using a 3 sided triangle fuse with enough room for battery and hardware.
again, this is all just a prototype/learning experience.

I'm also going to take the kiss principal to the extreme whenever I can. I think I'm going to try a 4mm wing with no dihedrial and run alerons. if I don't like the wing, ill just build up a new one. I'm also thinking a symmetrical airfoil actually really simplifies building and helps keep everything more standard shaped then a flat bottomed airfoil. I don't like the idea of using wing ribs because at that point, id rather just cut some balsa up on the laser cutter and have a much lighter wing. id like to rip a wing out in about 20 mins if possible

CHELLIE 12-24-2013 11:53 AM

Quote:

Originally Posted by hayofstacks (Post 935110)
thank you very much for the links.

after playing with the 6mm stuff, I simply can't believe how heavy it is. I made a 4ft long fuse to add a bunch of nose weight and keep cg in check, and its just too heavy. I was very surprised at how strong it was though. I let my 2 kids play with it. they actually set it up on a chair and were using it as a teeter totter , both sitting on each end.

I'm gonna start work on a shorter and smaller fuse out of the 4mm stuff and see what I come up with. I'm trying to plan around a 480-.10 sized electric on either a 3000mah 3 cell, or a 2200mah 4 cell. I'm trying to get it in the park flyer class, but we will have 380-450 watts and about 55oz of thrust to play with it

I'm hoping to get it in the 30-40oz all up weight, but I think it will still fly okay in the 50-60oz range. once I get a basic design down and get good at building with it, I plan to use 2mm where I can and lighten everything up overall. I may even step up motor size if I need more nose weight. I'm also starting to think a tapered 4 sided box fuse would be lighter with slightly less materials then using a 3 sided triangle fuse with enough room for battery and hardware.
again, this is all just a prototype/learning experience.

I'm also going to take the kiss principal to the extreme whenever I can. I think I'm going to try a 4mm wing with no dihedrial and run alerons. if I don't like the wing, ill just build up a new one. I'm also thinking a symmetrical airfoil actually really simplifies building and helps keep everything more standard shaped then a flat bottomed airfoil. I don't like the idea of using wing ribs because at that point, id rather just cut some balsa up on the laser cutter and have a much lighter wing. id like to rip a wing out in about 20 mins if possible

You Just have to Experiment with the corrugated Plastic when making planes, I think the 2mm for the wings like fhhuber said and 4mm for the fuselage will work good. you will Quickly become a Expert with Corrugated Plastic Aircraft building :D

fhhuber 12-24-2013 05:16 PM

Yo'll find that .25 (glow equiv) class will be about as small as you can get with coroplast and not be overweight.

Pilot Error 12-26-2013 01:44 AM

I am building a STIK (.40 size-57" wing) and thought I had some pics on here? I don't remember where i put them. It's all 4mm and that seems to be the standard among us SPADsters..Check these plans for more details..

www.spadtothebone.net look under free plans and see the combat planes made with 4mm..2mm is just lighter.

A couple pics from mine when I started it. It's pretty much built, minus electronics.

http://i1127.photobucket.com/albums/...ps55e826b2.jpg

http://i1127.photobucket.com/albums/...psfa51fe70.jpg

http://i1127.photobucket.com/albums/...ps0074332e.jpg

fhhuber 12-26-2013 03:58 AM

4 mil for the wings of a .40 size is OK. You can do the .40 size wings in 2 mil with a slightly beefier spar than when using 4 mil.

Just like if building with balsa you'd use some heavier materials for the structure of a larger plane.
You don't use 1/4 inch thick balsa for the sides of a built up box fuselage for a .25 size model. You might for a 50 cc size though...

Use what is right for the size of the airplane.

Pilot Error 12-26-2013 04:11 AM

Quote:

Originally Posted by fhhuber (Post 935241)
4 mil for the wings of a .40 size is OK. You can do the .40 size wings in 2 mil with a slightly beefier spar than when using 4 mil.

Just like if building with balsa you'd use some heavier materials for the structure of a larger plane.
You don't use 1/4 inch thick balsa for the sides of a built up box fuselage for a .25 size model. You might for a 50 cc size though...

Use what is right for the size of the airplane.

Yep. The only reason I'm using 4mm for wings is I can't get 2mm locally.

hayofstacks 12-26-2013 04:50 AM

after playing with both the 4 and 2mm stuff, I think if 4mm ends up being too heavy, ill opt for a balsa wing and coroplast fuse. if I use 2mm I think ill end up building wing ribs. if I go through that much effort, I might as well build it out of balsa. building up a dbox spar like the mini ultra stick wouldn't be much more work and would be much lighter. I consider the wing to be a good chunk of the way an airplane flies. I'm shooting for a rtf weight near 40oz. I think it would fly up to 60oz okay, but I want more of a sport flyer and want a good bit of power reserve for my motor system.

hayofstacks 01-03-2014 11:08 PM

http://i33.photobucket.com/albums/d8...1-03153933.jpg

completed 6mm wing weighs 17 oz and auw will be 40-45oz depending on battery and exactly how I build it.

40" wingspan, 10" chord. its just sitting on my slow stick for fun. I hid the airfoil. its not pretty but should work.

thinking it will be a .10-.15 sized plane. if I build up a 4mm wing, ill cut the yardstick main spar for a shorter height. I think I could get it around 10oz if I was really careful and shouldn't need any ribs for wing structure.

hayofstacks 01-04-2014 02:12 AM

http://i33.photobucket.com/albums/d8...1-03190617.jpg
figured out approximate cg, building up a firewall and rudder tomorrow.

gonna weigh 40oz minimum without landing gear.

Pilot Error 01-04-2014 03:46 AM

Looking good!

hayofstacks 01-31-2014 07:43 PM

Hmm...

http://i33.photobucket.com/albums/d8...2012.32.52.jpg


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