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Old Sep 11, 2011, 06:07 PM
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Freddie B's Avatar
Omaha Nebraska
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Wire routing cutouts.

Pre-thinking routing two servo wires after assembly, I came up with this thought. Much easier to do this now than after fuselage is closed up.

Skinny stick, and arrow show the cuts I made.

Fred
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Old Sep 11, 2011, 06:11 PM
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Freddie B's Avatar
Omaha Nebraska
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Pre shaping fuselage contours.

I now took the two outer assemblies and put them together with some painters tape. mostly to keep things ridged. Now I will sand the basic outer fuselage contours so that they will blend in well when I glue them on.

I don't like feathering FFF into a flat edge much and this makes my job easier.

Fred
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Old Sep 11, 2011, 06:20 PM
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Omaha Nebraska
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Sanding reccomendations...

Here is how I do it. Your way is good too.

I start with 60 grit paper laminated to MDF board, using Elmer's Rubber Cenment again. Really gets material off fast so be carefull and don't go too far.

120 grit on a block works fast enough to fine tune shape and remove deep scratches from rough sanding.

My 100 grit sanding sponge (1/4" thick sheet) really blends thigs nice.

You can see the results so far.

I will also do a coating of thinned light weight, sand. Then I coat with a mix of light weight, Talc Powder, WBPU, a dab of craft paint (for color) and water. Then I sand with 320 grit paper applied to a beaded foam sheet about 3/8" thick. Smooth as a babies arss at that point, and ready to paint.

Sounds like a lot of work, but it isn't. Goes real fast and I love the results.

Fred
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Last edited by Freddie B; Sep 12, 2011 at 07:23 AM.
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Old Sep 11, 2011, 11:28 PM
skumgummi dave
Gresham, OR.
Joined Mar 2004
1,786 Posts
Freddie B:

What a craftsman! It's fun to watch you work...

Dave-
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Old Sep 12, 2011, 07:26 AM
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Freddie B's Avatar
Omaha Nebraska
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Quote:
Originally Posted by foamdave View Post
Freddie B:

What a craftsman! It's fun to watch you work...

Dave-
Well thank you Dave! I'm glad you enjoy it. Funny thing is I still can't draw a straight line to save my life, and no one can read my writing...... But put some hand tools into the mix and everything changes.


I'll try to post some more pictures later, she is looking good at this point.

Fred
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Old Sep 12, 2011, 12:36 PM
Slipping the Surly Bonds
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Attica, MI
Joined Dec 2006
10,322 Posts
Fred,

Thanks for the kind words. Watching with great interest, and have to say ditto to Dave's comment.

Ken
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Old Sep 12, 2011, 01:22 PM
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Freddie B's Avatar
Omaha Nebraska
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Quote:
Originally Posted by dz1sfb View Post
Fred,

Thanks for the kind words. Watching with great interest, and have to say ditto to Dave's comment.

Ken
Thank you Ken, and I hope to not disappoint! What a great thing you have done on the first 28 plans... These planes are great making so many people successful and happy. Great that you offer the plans for free, but also supply inexpensive kits which so many would prefer.

The MiG 3 is such a neat plane and I am making this one special for my own personal satisfaction. I do hope when it's done you will approve of my small changes. I too hope to inspire others or impart some ideas that they too might use in their modeling career. Sharing ideas make us all better builders and keeps the hobby alive.

Power to taking foam to a higher level. I love working with foam BTW!

Fred
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Old Sep 12, 2011, 04:29 PM
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Freddie B's Avatar
Omaha Nebraska
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Finish up the fuselage.

Once the initial sanding was done, I laminated the outside left and right fuselage panels on.

At this point I sanded the entire fuselage to a pleasing shape as I did on the outside panels. I used a tiny bit of light wight to flair in the outer panels at the rear just using my finger to flow it into the transition.

You can see the whole fuselage was again 'painted' by brush, with the whip cream testure mix of lightweight, Talc powder, WBPU, a drop or two of white paint, and a little water. I brush the coating on faily liberal, and it goes on just like thick paint. I make sure to have even coverage.

Once dry I use 320-400 grit and the sanding sponge to all but remove the coating and it looks like the picture. All pores, scratches, and anything else is filled, flush, and primed. Very light weight too.

My enlarged firewall now cut, drilled, and pretty much sanded to the fuselage shape ready to glue in place is shown in the picture.

Fred
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Old Sep 12, 2011, 04:48 PM
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Omaha Nebraska
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FFF Fan Fold Foam information.

OK I'm placing this here if anyone cares, I did.

I have been building a lot with FFF foam, and I often build with the plastic skin on for strength, finish quality, and easy. Easy by way of I hate removing the plastic as it always gives me fits.

But here is some info:

1. I hand pick through the stacks of fan fold at the store until I find a pack that has somewhat thicker sheets, uniform throughout, few visable waves, and a pretty good finish on the painted side. These foam sheets are thicker than many I've bought. They measure .238" or just under 1/4". Maybe they improved the process, or I suspect they come out different each batch.

2. My sheets weight roughly 5.7 ounces with the plastic on.

3. The sheets weigh roughly 5.0 ounces with the plastic removed. For a 2' x 4' surface, thats plenty of weight savings.

4. depending on what I'm building the plastic weight may more than make up for it's self in added strength.

5. It is easier to work with bare FFF. Sanding and gluing is faster. But painting and finishing is more work. Boths ways have value, just different.

Last I weighed the plastic removed from a sheet of FFF for this build and it weighed 21 grams.
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Old Sep 12, 2011, 04:57 PM
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Freddie B's Avatar
Omaha Nebraska
Joined Feb 2006
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The all important wing.

On Ken's designs, they started with reinforced strapping tape on the bottom for the 'spar', and a KFm2 airfoil. Works well enough and especially at this scale and weight.

Next came the option for a single carbon fiber spar in the 3mm (1/8") range, or probably more often used, two, 24" long, 1/8" diameter wooden dowels glued on top of one another, with dihedral pre-bent into them. This dual dowel arrangement is light, cheap, strong, but best of all you can set scale dihedral into the wings which is the way I like because it's more stable and looks right.

All in all the Dz1sfb warbird fleet works wonderful this way.

But......I'm going to change the wing construction slightly on this 'Sport' version for a couple of personal reasons, but it might take more to explain than to do, so I'll be posting some photos.

Fred
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Old Sep 12, 2011, 05:10 PM
a.d.m.i.n
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Joined Jan 2011
415 Posts
Wow, nice build
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Old Sep 12, 2011, 06:56 PM
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Freddie B's Avatar
Omaha Nebraska
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Thanks Reptor!

I am going to change the wing only that it is going to have a more conventional airfoil, but retain a very thin thickness. It shall mimic a sailplane type wing, very fast, little drag, great pitching moments. Although like a sailplane it will not bleed off speed quickly, probably ground plane forever, however hopefully retain better slow speed lift than a KFm airfoil.

The wing will have an airfoil similar to an EH 1.0/7.0, or 64A008. Figuring root cord will be 6.85% thick, and the tip cord 13.7% thick. This thicker section at the tip seems to improve lift out there when we need it most.

Ailerons will be shortened in length at the wingtip to improve tip stalling behaivior and tame the high G tip stall or snaping tendency.

I wouldn't change anything if it were not for the proposed landing gear, the few 'scale' additions, increased wingloading, and where I will be flying this plane.

All this and it will be easy to make!

Fred
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Old Sep 12, 2011, 07:09 PM
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Freddie B's Avatar
Omaha Nebraska
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OK credit to Ken again, learned a few tricks from his posts over time.

1. I will soak the wooden spar in water to soften the wood to form the dihedral joint.

2. Place this onto a jig made from an old 2'x4' and finishing nails to dry so it will retain the dihedral angle.

3. I am using 5 degree per side (10 degree total).

4. I will use 3/16" diameter wooden dowel instead of two pieces of 1/8" for a 1 gram penalty.

A couple pictures. I use a foam cup with a slightly smaller hole, poking the dowel through it. This lets it soak only in the area of the bend, and I get no leaking water from the cup.

Fred
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Old Sep 12, 2011, 07:18 PM
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Freddie B's Avatar
Omaha Nebraska
Joined Feb 2006
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Starting the wing panels.

I draw a straight line, and another crossing it using a square.

I work with only a half pattern when I make wings. I just place it on each side of the line which gives me a perfect mirror image for the opposite panel. 4 placements of my pattern, and a red sharpie marks the spot.

Next using that straight line from before, I mark where I want my spar placement to be. I did this in green sharpie to help show you what I'm doing.

Quick work with a yard stick and a square.

Fred
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Old Sep 12, 2011, 07:27 PM
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Freddie B's Avatar
Omaha Nebraska
Joined Feb 2006
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So I take out my Dremel rotary tool, attached the Dremel router base accessory, with a round rasp bit that is close to a 1/4" diameter. The bit came in a small set, some off brand, China made I guess, from Menard's Home Improvement store.

I drew a line on some scrap (that old FFF that wasn't so nice). Place a straight edge (MDF Board) on the line. Ran the Dremel down this edge, and then measured how far form the line the slot is cut.

Now my straight edge needs to be that far from my intended spar slot, so I made a black line on the wing layouts for this procedure. You will see that black line in the photo posted above.

Fred
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