INDOOR SEASON IS HERE! – CUTTING THE PARTS

[Matchless]

INDOOR SEASON IS HERE! – CUTTING THE PARTS

Its been a bit since the first installation of this article, so hopefully you’ve gotten hold of all the necessary materials for building your foamy. If not, then follow along so you can build when you’ve got it!

Getting the foamy plans in a usable format can be somewhat difficult, but does not have to be. Most are either in PDF Format or in DXF/DWG format. The first format (PDF) can be printed using any of the free PDF format softwares available on the net. For DXF or DWG (both are CAD formats) you need to use a CAD software or CAD printing freeware from the net to print them. Just do an internet search for “CAD Printing Software” to find what you need. The final alternative is to have them printed fullsize at a printing shop. For this project, I’ve included PDF and DXF’s of the overall plan, as well as the patterns for the part.

Free PDF Software from Adobe
http://www.adobe.com/products/acrobat/readstep2.html

The watchout with all of these methods is that all printers create some error in sizing at times. Your plans may print too small or too large. Either way, your results may be compromised. The easy way to check for correct printing is to check the wingspan of the plan against the specified wingspan for the airplane. For the JUKA, the wingspan is 32.38 inches. If you print the plans, and they are off by an eighth of an inch one direction or the other, it will not likely affect your build much, however if its an inch off, you will have to do significant adjustments to the parts as you fit them up.

I’m going to use a free CAD software from the net called TurboCad 2D to print mine in ‘tile’ format. After printing out the patterns for each of the parts, I am going to lay out the tiled sections of the plans on my workbench and tape them together with clear tape. As I do this, I am going to lay my stainless straightedge over the plans and align it with a straight line on the plans (such as a leading edge or hingeline) so that I know I am getting the plans completely straight- Don’t omit this part, as omitting this will result in a crooked airplane. A little clear tape joins the tiles and makes it usable.

Next up, I’m going to cut the extra from around the patterns to help in lining up the parts on the depron. Much of my initial experience with this comes from watching my grandmother lay out sewing patterns on cloth when I would visit her as a kid.

Now its time to get out the 3M Restickable Gluestick that is on the materials list. I get my Gluestick from an office supply store. Make sure you get the genuine 3M stuff, as I had pretty bad experiences with the copycat brands. This stuff is one of the best tools I’ve ever used in modelbuilding. I use it to cut parts from patterns all the way from giantscale to foamies. Smear the gluestick on the back of the pattern and lay the pattern on the depron sheet and press it down lightly. If you don’t like the layout, move the pattern around on the depron until you do.

Once all the patterns are laid out on the depron sheets, put a new #11 blade in your blade holder and pull out your stainless straight edge. Don’t ever cut a straight line without a straightedge to guide the blade and don’t ever make a cut with a dull blade. There is no sense in ruining a $4 sheet of depron because you tried to save money and used a dull blade.

I start my cuts by cutting all my straight lines. I then cut all the curves. The next helpful trick is to leave the ailerons and other control surfaces attached to their mates as you cut by leaving a small ‘tab’ between the parts. Same goes for the upper and lower fuse halves. This keeps the parts together for painting and makes that job so much easier. I draw little squiggles every couple inches on the patterns to indicate where I’ll leave a ‘tab’.

After carefully cutting all the parts, you can dress the edges lightly with the sanding block if necessary. Finish them by wiping both sides of each part with a rag soaked in alchohol (I use rubbing alchohol from the drugstore). This removes the 3M adhesive and any oils from your hands or arms. Don’t omit this step! Oil and adhesives or other chemicals on the depron will result in a horrible effect called ‘fisheye’ (in the automotive painting field). It’s ugly and is easy to avoid.

If you plan to do any milling of the foam, now is the time to do it. Milling is by far easiest when the parts are still flat and unassembled. For my freestyle practice airplanes, I typically don’t mill them. I tend to ‘bash’ my Freestyle airplanes around much more violently than my F3P/Indoor pattern airplanes, so the milling is somewhat out of place there. However, for competition, or if I only have a smaller practice area to practice in, I will mill my freestyle airplanes. Done right, the weight loss is worth it.

Check out this link for a how-to on milling depron and other foams.
Foamy Season is here - Milling Depron Foam -> A How To

After cutting all the depron parts, you’ll need to make some hardware. I hand cut all my hardware from 1/32” plywood, but have recently begun trying develop a good set of lasercut plywood hardware. To cut the parts, I use the same Restickable gluestick method, and I use scissors to rough cut the parts. I then use a sanding block for final shaping. With this method, I can make a set of hardware in about 10 minutes.

Why on earth would I go to that effort for the hardware? Personally, I have not yet found a set of hardware that I like. All the different types out there have good features, but they all have their shortcomings, such as; lack of gluing area for good support, poor linkage design, or heavy weight. I’ve developed the ply hardware shown on the plans over the past 5 years and I’m pretty pleased with its performance.

Next installment is Finishing, so get your finishing supplies ready and be ready to lay some paint. I am by no means the best foamy painter in the world (Look to guys like Gary Pierson, Stan Watkins, Gator Smith and Donatas as the levels to aspire to), but over the years I’ve managed to pick up some slick little tricks to help you make your foamy look like a pro painted it!

For those who missed part one, here is the link Ultimate Indoor Foamy Build, The Series!

[Matchless]

...

[gareth.ky]

Some quick ideas/other ways to do it:

I gave up on tiled plans after I found out that Kinkos will print plans on their large format black & white printer for $7 or $8. I figure my time is worth the money. Tiles can be a PITA and this is supposed to be fun right? Jus take a PDF in on a USB stick and ask them to print it on the large format black & white printer at 1:1 scale. The printer can print up to 36" wide and any length, its fed from a roll of paper.

I use 3M "Spray Mount Artists Adhesive" to tack the plans down to the Depron. You can get it at Hobby Lobby in the drafting section. Don't try 3M77 it will stick the plans down permanently.

I stopped rough cutting the parts out of the plans because this makes them more prone to bending when they are being laid on the Deporn. I use big pieces of paper the size of the Depron sheet and just stick the whole thing down. I use the CAD program to lay out the parts so I don't waste too much of the sheet. Matchless is right, you want to check it with a straight edge.

Keep 'em coming Matchless!

[f3martin]

Sweet, great thread,

I have just started getting into indoor f3p and have a donuts models Nexus and Dualsky brushless with integrated esc, AUW 105grams without batt with 4x 6g servos and is great, but a I want to improve some bits, so this thread is at the best time

Cant wait till the next installent

Keep up the good work
Martin

[del]

Matchless , have the PDF files been posted yet ?

Thanks, Dorin Luck

[Matchless]

Hey Dorin! The PDF Files are in the first post of the initial thread : )

Ultimate Indoor Foamy Build, The Series!

Gareth, I used to use the spray adhesive, but I hate the overspray it creates and its a good bit more expensive.

F3Martin, that is an awesome weight for that build set. Great job!

[Trisquire]

	Quote: Originally Posted by gareth.ky
	Some quick ideas/other ways to do it: I gave up on tiled plans after I found out that Kinkos will print plans on their large format black & white printer for $7 or $8. I figure my time is worth the money. Tiles can be a PITA and this is supposed to be fun right? Jus take a PDF in on a USB stick and ask them to print it on the large format black & white printer at 1:1 scale. The printer can print up to 36" wide and any length, its fed from a roll of paper..............

I wonder if you have to give Kinkos a frame of reference such as, "Please make sure with wingspan comes out to 32.38 inches."

Tom

[f3martin]

Thanks Matchless, I was really pleased too, my previous shocky was Ikarus Yak at 350g !! (MG servos, big lipos, ...) So I was really pleased with the Nexus after all its not the absolute lightes setup, 26g Dualsky motor with esc, 5g hitec 5ch rx, 4 6g jamara servos. But flies great. Only problem is rolls are slow, real slow, this I thought was strange as each aileron has 1.3kg servo on it, maybe the air brake on the aileron is slowing it down??

Get painting !!!!


Martin

[ckoerner]

Hopefully Matchless doesn't mind me chiming in here. I glue my plans to poster board. Then I cut them out. Trace the template outline onto the depron with a pencil. It will make an indentation into the foam. Then cut on the lines. Use a ruler for straight cuts. No glue on the foam either. There are many ways to do this. It's interesting to see the other way people do it also. I never thought to glue it to the depron. Keep up the good work Jeremy.

[gareth.ky]

	Quote: Originally Posted by Trisquire
	I wonder if you have to give Kinkos a frame of reference such as, "Please make sure with wingspan comes out to 32.38 inches." Tom

No, just make sure you tell them not to shrink it. I say things like "Print it full scale" or "Print it one to one" or "Don't shrink it!". I have never had them print one too small.

[poring]

Well I just printed the PDF and it comes out too small by one approx one inch. (WS and length) We use the A4 page format here in Europe which isn't the same dimetions as the US format, could this be the cause?

[gareth.ky]

In Adobe and Foxit Reader there is a print dialog that you can use to tell your printer NOT to scale the print job to fit the page.

In Adobe it is called Page Scaling and you want the "None" option.