Curved Fuselage Panels From Foam Poster Board

by dharkless | January 7, 2014 | (17) Posted in Projects

Hi Guys,

This is the article I mentioned about making curved panels with foam poster board.  I am still working out methods but this is what I have so far.

FIRST ATTEMPTS:

The first attempts at making curved panels were just working with a couple of scraps:

I scored the backs with a fingernail and then hand formed the curves.  I used a magic marker to help form the one below.

 

 

Let's see if this works for real,,,

 

RAPTOR TOP PANELS:

I have made my first attempts on an actual project here.   I formed some curved top fuselage panels for the 24" F 22  Raptor that I had made bottom fuselage panels for earlier.

The first piece was the one with double curved sections and a flat piece between that was to fit between the rudders. I started by cutting a piece the right size allowing for the curves.  I then made 50% cuts to define straight and curved parts. Thus:

Next I removed the paper backing on the two outer sections and made knife scores about 1/8" apart along the lines of the bend.  As I expected, this allowed those areas to be formed into curves pretty easily.  I used a smear of hot glue to lock the curves into place.  Not too much.  The exposed foam melts pretty easily.

Scoring. 

Hand forming is easy with the score cuts.

The edges were back-cut and sanded smooth.  Then hot glue was applied to both edges and the middle flat spot.  Carefully hold the edges down while pushing the flat center down into place.  Hold everything and fine tune as the glue takes hold.

The end result with rear notches like the real thing.

A similar method was used for the one piece front fuselage panel.  The middle flat spot and rear curves were made the same way.  The rough piece was made to fit with about 1/4 over on all sides and then shaped.  The scores on the back were flared to match the tapered shape (about 1/8" apart at the back edge and closer to 1/4" at the front.  I also made cross cuts from the front tip to about 3/4" past the front angle so the piece could bend the other way.  The back edges were formed and stiffened with a smear of hot glue before final fit.  The front edge was left pretty flat.  Everything was back cut with a knife and then the perimeter was traced.  The piece was trimmed to the final fit and then the back cuts were sanded to a fine point and to lay flat. After checking the final fit I marked the position and then glued one side.  I as able to lift the second side to apply the glue to it.  It was a little tricky to get the very edges of the tapers glued down.  I had to squeeze a little hot glue into the joints after the main glue dried..  Doing this helped to roll the leading edges down which was a plus.  I had one spot where the glue skinning on the back deformed the panel slightly (because I used too much) but overall I am happy with the results.  If it was perfect I would have nothing to improve upon next time.

Notice that the front edge of the flat part behind the slot rests on top of the blue foam to help establish the shape.  It is glued down to the wing at the back.

I may rework the lower fuselage panels before I am done.  They look too squarish now.

That blue foam nose is also bothering me...

Check back for my updates.

Happy building!

 

Update:

I have added the curved panel cockpit...

This was made from 4 panels and was tedious to fit. I found that the panels form curves easily by pulling over a table edge using light hand pressure.  I did foam side down then had more curve than needed.  The last piece was hard to place before the glue set so there are a couple of open seams.  I am planning to try the iron techniqe to seal them,  The only fold is at the bottom of the canopy  That was done with a curved back cut.

I also added a curved panel cone to form the mount and conceal the motor.  The mount is a piece of plywood just glued to the inside of the cone before gluing the whole assembly down.  The cone was formed by making closely spaced radial back cuts and then forming around a magic marker.  

After the iron work I am ready to paint and or fly.  Still waiting for suitable weather for both.

 

The whole thing:

Top side:

 

Botton side.

 

I added a softer nose to a previous project:

 

This is a flying wing that I designed to make an airplane to be made from one sheet of foam with no waste and no extra foam.  The original version has a smaller nose and is not a true floppable.  This version adds the material to make the nose and canopy to make it a floppable.  I have submitted a separate article on it.  It should be posted soon.

 

The prepared blank:

Here is the prepared blank before assembly.  The upper middle section has the paper removed fom the beginning of the curved area up.  It was pre-curved by running over a table edge foam side down with light and pressure.

COMMENTS

eagle4 on January 16, 2014
Fantastic work mate. Your f22 looks so much better now. I wonder if there will be any flight characteristics that have changed. I doubt it. But maybe you'll get more lift due to the lifting shoulders.
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dharkless on January 18, 2014
I am just getting back into the hobby after about 15 years off. I have not flown any of these yet but am eager to do so when the weather breaks, I did all of these modifications after building the F 22 per plans. I will probably build another one per plans and fly it first to get my flying skills back up before risking this one. I will post something then.

Check out the update with the curved panel cockpit and nose.
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LordVader on January 16, 2014
Very cool, more realistic features always makes a plane look better.
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bensgreentrain on January 16, 2014
Hi, Benny here in Tx. I to am experimenting with bending DT foam board. I've been out of the hobby for about 10 yrs. I was lucky to find this excellent web site, and I'm learning a whole new way to build. I'm combining Armin with FT and some of my own ideas. I'm building a cub from an old set of Goldberg anniversary plans, yes it's a 60" ws. Currently the weight with electronics is 44 oz. I think bending foam board is an excellent idea it seems to make it stronger after bending. Keep up the good work. benny
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dharkless on January 18, 2014
Hey Benny,
Have you posted anything showing what you are doing? If not, you should. The great part about this site is the free flow of ideas.
I have submitted an article about building a flying wing using one sheet with no waste and no added material. It includes a second version using two sheets. That one has a 60" wing span and seems to have plenty of strength.
Show us what yo got!
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Gryf on January 16, 2014
Oh, that looks nice! An added bonus would be that the curved surfaces will be stiffer than if they were flat. Great work!
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Da99er on January 16, 2014
I've also used 3/4" blue foam for the fuselage... At first I cut the fuse "accross the grain" so that it was stiffer, but it tended to break easier. I found that if I cut it out length-wise "with the grain" and then inserted popsicle sticks into slits cut along the top and bottom, it was much harder to break.
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dharkless on January 18, 2014
Mine was 1/2". It seemed stiff enough by itself. I was able to balance by placing the battery within the bottom panels under the forward part of the wing. Everything is concealed and still has good ventilation. The FT article for building this mentioned the grain issue so I did mine that way the first time. I did a 30" version and used 3 plies of foam poster board for that one. I like the looks of that better and will probably do that if/when do another small one. I also reshaped the nose to look more like the real F 22 before adding the curved panels. The one on the plans looks more like an F 16 actually.
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Mizzster D Double-a on January 17, 2014
nice man, i think next step is to work on 3d nose :)
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dharkless on February 1, 2014
Thanks. The 3D nose is done. Check out the updated photos.
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shadowolf on January 17, 2014
You can also remove the inside layer of poster board and it will curve nicely also and make it lighter.
Give it a try.

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185Dave on January 18, 2014
Take any shape that you want and cut it a little bigger. Then on the bach side of that piece don't take off the paper leave it on. At the hardware store pick up a tool that is made to help install screen in a screen door. The groves that it makes are great for bending the paper. or score lines, Works good for me. hope this helps. The tool is only a few bucks. Keep the wind at your back.
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Yogenh on January 18, 2014
It looks great and I will have to work with that too thanks for the tip

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UltraPigeon on January 31, 2014
WOW
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Damig on July 21, 2015
update? Update? I love the details and smooth curves. Great work and thanks for sharing... I to am energized again, as are you, after many years of not flying the little nitro "Boards"...

=daMig=
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dharkless on July 22, 2015
Thanks for the kind comments.
Sorry, there is no update available on curved panels. I wrote this about 18 months ago and then went in other directions.
I did a bunch of designs with the concept of making a plane from a whole sheet (or 1/2, or 2 or 4 sheets) with no waste. After about a year I am still playing with that.
Click on my name at the top and it will take you to all of my aticles.
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Curved Fuselage Panels From Foam Poster Board