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Oct 28, 2015, 07:18 PM
RC 4 Life
sparks's Avatar
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back to it

The tops of the spars are square and will require light sanding to give them a curve so the top sheeting will not have humps on the surface.

Before you start sanding, mark the spars with a highlighter pen.
This will help you keep track of your progress.
Using a sanding bar wide enough to bridge between the spars will help to ensure the angles blend between them.
Do not sand front to back , diagonal and span wise will keep you from breaking the spars loose.
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Oct 28, 2015, 07:20 PM
RC 4 Life
sparks's Avatar
Thread OP
Sand the trailing edge of the wing tip first to prevent snagging it .The leading edge strip should taper to about 3 mm and the tip piece should taper to match it.
The trailing edge should have a slight taper as well to keep the trailing edge thin. Once you are finished sanding; place a strip of foam across the spars and check for gaps.
Oct 28, 2015, 07:23 PM
RC 4 Life
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Gear Plates

If your model will have landing gear it would be best if you bond the gear plates in next.

Cut the bottom sheeting at the end of the S-1 spar to the leading edge. Slip the leading edge shim under the wing panel,
(thick end at the root).
Bond the gear plates to the wing bottom sheeting.

Note use enough weight to clamp them in place and bend the foam.
We are looking to make the bottom of the wing curved at the root. The gear plate will hold this curve after the glue sets up.
Nov 02, 2015, 08:32 PM
RC 4 Life
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Top sheeting

Trace the wing shape to your work surface then use the marks to cover your work surface with plastic packing tape. or plastic sandwich wrap. This will prevent you from bonding the wing to the table.
Tape the leading edge spacers / shims to the table where the leading edges will be to keep them from moving.
Re mark the hinge line with a marker. this will identify the hinge line later.
Nov 02, 2015, 08:34 PM
RC 4 Life
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Bonding the panels

Put the wing panel in place on the table over the leading edge shims and put weights on the center section to keep it from moving.

Reminder: Apply another coat of highlighter ink to the hinge line. I forgot to and paid for it later.

Apply Gorilla glue to the spars, wing tip, leading and trailing edge.
Align the trailing edges and apply weights to the entire length first.

Roll the top sheeting over the spars then use a stiff panel leaning against the top of the leading edge with weights on top for clamp pressure.
This method allows you to apply as much weight as you need evenly across the wing.
Finnish up by adding weights to the wing tip.
Now just walk away for at least two hours.
Nov 02, 2015, 09:54 PM
When cows fly!
Also watching this one!
Nov 05, 2015, 07:58 PM
RC 4 Life
sparks's Avatar
Thread OP
Trim the spars at the wing root with a razor if they are a little long.
Then block sand the spars and the sheeting flush and 90 degrees to the bottom sheeting. Raise the wing tips 1 and a half inch from the work surface and continue sanding till the sheeting and spars are flush to get the dihedral angle.
Nov 14, 2015, 02:15 PM
RC 4 Life
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With the dihedral blocks in place, Use small weights to hold the center section down.
Fit the spar joiners in-between the wing panel spars and bond them in place.

To fit the spar joiners; cut the width first, slide it in place, mark the point where the bottom of the top sheeting meets the spar joiner on both sides the cut between the marks.

Note the use of the shim along the leading edge to bring the bottom sheet up to meet the outboard outer sheeting.
Nov 14, 2015, 02:16 PM
RC 4 Life
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After the joiners have dried; sand the joiners to match the spar angles.
be sure the 6mm panel is bonded in place to hold the hatch magnet.
Nov 14, 2015, 02:18 PM
RC 4 Life
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With the wing off the dihedral blocks, cut a panel to fit the center section.

Itís easier to get it close with a knife and straight edge and do the last adjustments with a sanding block.

Donít worry about tiny gaps in the panels.
When you bond the panel in place and the weights are holding it to the table, slip the Dihedral blocks back in place and the gaps will close up.
Nov 14, 2015, 03:27 PM
An itch?. Scratch build.
eflightray's Avatar
This cartoon 'P-51 looks and flies quite impressive, even the build looks incredibly light.

Q版P51飛行無配樂 (4 min 52 sec)


Not so much intended as a 'cartoon', but my more a slimmed down Wild Cat --
Nov 15, 2015, 08:02 AM
RC 4 Life
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Thread OP
Since we are off track now . . . . . .
Ray , I think you should build one of his designs.
As a warning , you may walk away with a different opinion. . .I did
He has free patterns someplace on RC groups and a friend and I built his Fatty 737, I made two.
In a nut shell:
Great construction learning experience If you like trial and error.
Build two or three so you are not starting over.
The plane flew OK but it is very sensitive to thrust line adjustments.
Fly over tall grass only, any mishap will put you in the shop.
Never come off the throttle more than 3/4 power.

My impression : I'm glad I took as shot at a fatty plane, there was lessons learned about what not to do with the Cartoon planes. My friends and I had a few laughs trying to get it to fly and was thrilled when it did.

Build one Ray and let us know what you think.
Nov 16, 2015, 08:29 PM
Watt Waster
Tsavah's Avatar

Fatty, super thin foam Airplanes

If you have seen his other creations, you are aware he builds very lightweight foam shells and is a master at this craft. The rest of us can only hope to get the hang of it. In some of his other video, of which there is more than a few dozen, he shows just how sensitive to wind, damage, and weight gain the models are. Most of us need something a bit more robust and Sparks has developed a line of cartoon flyers that fit that bill better.

To be honest and upfront, I tend to also do the thin shell construction method, but prefer to first make a build-over frame, or plug, and construct the thin shell fuselage on it. I have more about this method in my blog, so I won't got into a lot of detail here. Now Sparks can get back to his show-n-tell.
Latest blog entry: Center of Gravity - Airplanes
Nov 19, 2015, 09:05 PM
RC 4 Life
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Thread OP
Before we get to the ailerons there is some time consuming steps to do.
If you have not done it already it is time to trim and sand the edges of the wing to shape. We are looking for a smooth radius that blends into the sheeting. I start with 120 grit and finish with 280. Sharp leading edges stall a wing quickly.
The sanded portion may feel smooth but when it is painted it will look fuzzy. To fix this I coat the sanded areas with wood workers glue spread with my finger. This fills the open cells of the foam and gives the wing a crust for ding protection. After the glue has dried it will feel very rough; sand it once more with 280 grit and reapply and you are done.
Nov 19, 2015, 09:07 PM
RC 4 Life
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While all that glue was drying I went to work on the tail feathers.
Nothing special here, cut them out using the patterns.
Sand the edges round.
Separate and hinge.
There is a few tricks though. If you lay a pencil on its side it will mark the centerline on the edge of a 6mm panel.
Also if you butt a hinge line together and push a pencil between them it leaves identical marks making your hinges line up perfectly.

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