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Help! How can you modify a plan before printing?

#1
There are good tutorials for how to turn a full-size plan into a colored skin for your airplane, but my problem is I live in a place where the available foam is 5mm rather than 4mm. It already doesn't have any paper on it, so I want to print full size plans to use as the skin of the airplane, but the difference in foam thickness causes a huge number of misalignments. So again I'm wondering, to actually modify the dimensions of the plan itself, how would you tackle this problem? Scaling, by the way, is not an option, because I don't want a final plane that's 20% larger than the original.
 
#2
What am I really asking.... Is there a program where I could take a FT plan and modify, for example, all fold channels to be 5mm wide instead of 4mm wide? Please note that any such program I would have to learn from scratch, other than the most basic of familiarity with SketchUp.
 

Chappie66

Active member
#3
I have done this in couple of ways.

One is to redraw the entire plan using your favorite software. Adobe Reader, the version I am using, has tools that allow measurements. Re-drawing takes some time but you can customize it in whatever fashion.
Another avenue that I have recently started using is to convert the PDF to DXF. Then I import that into visio or a CAD program like DoubleCAD XT (https://www.turbocad.com/content/doublecad-xt-v5). You can basically "trace" the plans and modify to create what you need.
 
#4
I did not know you could convert a PDF into DXF. I will try that! It's daunting to learn a new software, but it sounds like my best option. Thanks for the tip!
 

d8veh

Elite member
#5
When I used to make panes with laser cut balsa wood, I used Corel Draw to trace the image. It converts the image into vector format so that you can select and group segments to move around. IIRC, it only traces BMP format files, so you need to convert the PDF to BMP. I'm not sure, but I think Corel Draw can do that too. I know it can import PDF files, so it can probably save them as BMPs , which will then let you trace it. The trace function is automatic. You don't have to trace it yourself.
 
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Merv

Legendary member
#9
Redrawing the plans will work. There may be a better way. Cut both sides of the A or B fold at one time, with just the perfect spacing to fit your foam.

I take 2 utility blades, a small binder clip & a stack of index cards. Cut the index cards into a size that will go between the utility blades and still leave a good amount of the blade to stick out. The trick is to figure out how may index cards it takes to leave the perfect gap, then glue them together with Elmer's . Hold the stack together with the binder clip, use a straight edge & cut. Always follow the line that will make your plane the correct width. If you plane ends up being 1mm or so, taller or shorter than the plan, who cares.
 

Chappie66

Active member
#10
Redrawing the plans will work. There may be a better way. Cut both sides of the A or B fold at one time, with just the perfect spacing to fit your foam.

I take 2 utility blades, a small binder clip & a stack of index cards. Cut the index cards into a size that will go between the utility blades and still leave a good amount of the blade to stick out. The trick is to figure out how may index cards it takes to leave the perfect gap, then glue them together with Elmer's . Hold the stack together with the binder clip, use a straight edge & cut. Always follow the line that will make your plane the correct width. If you plane ends up being 1mm or so, taller or shorter than the plan, who cares.
I like that idea. Going to have to try it out!
 

Merv

Legendary member
#11
I have found the "alignment tabs" that FT uses to be more trouble than they are worth. I cut out my planes, ignoring any tab. On a wing spar, I just draw a line where the spar goes & hot glue it on.
 

Merv

Legendary member
#12
Andrew Newton uses depron covered with tape or laminate. I've never seen him build a FT plane but I see no reason why his methods would not apply.

 

Chappie66

Active member
#13
There are good tutorials for how to turn a full-size plan into a colored skin for your airplane, but my problem is I live in a place where the available foam is 5mm rather than 4mm. It already doesn't have any paper on it, so I want to print full size plans to use as the skin of the airplane, but the difference in foam thickness causes a huge number of misalignments. So again I'm wondering, to actually modify the dimensions of the plan itself, how would you tackle this problem? Scaling, by the way, is not an option, because I don't want a final plane that's 20% larger than the original.
Which plan are you currently looking at modifying? I have a few already captured in VSDX format, somewhere
 
#14
Which plan are you currently looking at modifying? I have a few already captured in VSDX format, somewhere
I use the Sparrow for my new FT-Stem based class here in Taiwan. So far I've been largely following the suggestion to just recut the channels with the right width, but that gives us two problems. One, it makes the width of the fuselage interior smaller, and two, the nose doublers still have only a 4mm lip around their edges, and compensating for that is asking 7th graders to freehand a parabolic curve on their first model :)

For myself, I've built a Mini Sportster at home, but these same problems of interior volume loss are compounded when the space between the nose doublers is reduced by 4mm. My mini power pod wouldn't fit, and by the time I've reduced it in size to fit, it's practically rubbing the motor on each side.

If I could modify the Sparrow plan, I would increase the channel between the bottom and sides by 1mm each, and then reduce the curve on the nose doubler piece by 1mm all around the curve. Since these are chuck gliders, that should be fine. For the Mini Sportster plan, I haven't figured out yet how to maintain enough spinning space between the doublers... just widening the channels so I don't have to cut the fuselage narrow might be sufficient.
 
#15
Andrew Newton uses depron covered with tape or laminate. I've never seen him build a FT plane but I see no reason why his methods would not apply.

This is exactly what we're currently doing; covering this foam with clear packing tape. It definitely works! But it's labor intensive with a classroom of kids who in some cases are still learning how to peel tape off a roll without sticking themselves to the table. :)
 

Chappie66

Active member
#16
OMG that is awesome and hilarious at the same time. Those plans I have not tackled yet. But will take a look at the time to create at least a modifiable version...
 
#17
OMG that is awesome and hilarious at the same time. Those plans I have not tackled yet. But will take a look at the time to create at least a modifiable version...
Thanks for the assist Chappie :) I'll also look into these programs that have been suggested and see if any of them are manageable.
 

jpot1

Elite member
#18
I would recommend Inkscape for something like this. You can import a PDF into it and then ungroup the plan into its components. It includes measurement tools to allow you to adjust spacing and other shape sizes. Very easy to use and free.
 
#20
I would recommend Inkscape for something like this. You can import a PDF into it and then ungroup the plan into its components. It includes measurement tools to allow you to adjust spacing and other shape sizes. Very easy to use and free.
That actually sounds just like what I need. Thanks for the tip!