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Apr 27, 2019, 01:43 AM
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ErcoupeEd's Avatar

Foam Connie


Sparks,
I bought both of your books and now you are inspiring me liight out on an adventure.
I have plenty of foam sheets from Menards, 2 inch, 1 1/2 , 1 inch, 3/4 inch and 1/2 inch
and some pink fanfold.
Stacks of foam stored in the third bay of my garage.
My ideas are to build a 90 inch span Monocoupe 90AQ from an IkonNwst plans,.
A 100 inch span T-28 from plansI boughton Ebay and matybe an 82 inch span Curtiss Robin from blown up Flyline plans.

I have two sets ofa Sirius 102 inch spanairplane
I do have a Tekoa feather cut system with all of the accessories they originally came with
I have a largeworkbench, 4 by 8 feet in the center of mybasement workshop Ican cut foam on also.

I have thought of starting with something small first , a 54 inch Taylorcraft using a Comet set of plans.
I will be following this Connie!
I am trying to locate a Tarvin epoxy glass 1/4 scale Ercoupe fuselage and build foam wings for it, and foam tail feathers!
I do have several sets of Jim Messer Ercoupe plans.

In 2002 I was at the National Ercoupe reunion at Mason Michigan,. where nicely tucked into a hangar was the "only" 4-place Ercoupe ever built, but never finished.
What a cool project it would be to model that!

Thanks!
Ed in Indiana
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Apr 27, 2019, 01:51 AM
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ErcoupeEd's Avatar
Quote:
Originally Posted by sparks
For some reason there is no sound with this video
Okay found problem on my end. Somehow my computer turned the sound down to zero.
Last edited by ErcoupeEd; Apr 27, 2019 at 03:43 PM.
Apr 27, 2019, 04:08 AM
flyin' fool
goldguy's Avatar
Just watched the vid, no problems. Sure is a wonderful project. You've got lots of tenacity for sure.

I slice my foam up the same way, except that I cover my table with parchment paper to make it slippery.
Last edited by goldguy; Apr 27, 2019 at 04:18 AM.
Apr 27, 2019, 07:10 AM
RC 4 Life
sparks's Avatar
Thread OP
Yes! a Monocoupe would be a fun project built like this, just remember you need more formers to keep the fuselage skin from showing them.

Parchment paper
Never would have thought of that, much easier to store too.
I'll have to get some to have on hand.
I'll probably still do what I'm doing because my work surface takes allot of abuse.
Besides; I love starting a new project with a new table cover.
Apr 27, 2019, 07:16 AM
RC 4 Life
sparks's Avatar
Thread OP
Eyeball the alignment of the center lines and water lines on the formers and adjust.
Then measure the waterlines from the build surface to make sure the formers are aligned.
To hold them in place and keep them from rotating we will use masking tape.
To apply the tape, pull off a long length and loosely lay it on the top of the formers.

Stick one of the mid formers edge to the tape firmly. Pull the tape taught but not enough to move the former then stick the tape to the edge of the next former.
Repeat going the other direction and alternate directions until all the formers are locked in place.
Apply tape strips to the sides at the 9:00 and 3:00.
In hind sight I had to add two more to the 5 &7 positions as well.
Color the edges of the formers with a dry erase board marker.
This colored edge will allow you to see what you are doing for the next step.
There will be small imperfections in the cuts you made while cutting out all those formers.
Holding a fine grit strip of sandpaper by both ends and dragging is gently over the former edges will even them up and improve the contact between the sheeting and former.

Never allow the sandpaper to contact less than three formers.
Never continue sanding when the applied color has been removed. (this means you are changing the shape)
Always sand in one direction and at an angle.
Apply 4 strips of tape to the sanded formers and rotate the fuselage to touch up the bottom.
Apr 27, 2019, 07:19 AM
RC 4 Life
sparks's Avatar
Thread OP

Sheeting .


I experimented with using PVC tubing to pre shape the sheeting and found in the end that it was just as easy to shape the curve by hand.
Using my hands for shaping actually worked better because I could curl the ends tighter than the middle for a better fit.
For the first sheet I got a little greedy because I wanted the hatch hole to have no seems involved so I cut the material wide enough to go ˝ inch beyond the balsa supports.
As length goes I went from the back of the cockpit to the front of the stabilizer mount.

In the end, I sheeted the fuselage with 7 panels.
This took considerable shaping and edge to edge adjustments.
The truth is I was trying to avoid seams that turned out to not be that hard to deal with.
If I had it to do again I’d use smaller sheets.
Apr 27, 2019, 07:25 AM
RC 4 Life
sparks's Avatar
Thread OP

Applying the first sheet.


Pe shape your first sheet the best you can.
Hold it in place with a few strips of masking tape while you mark the edges of the formers.
The marks are there to show you where to stop applying glue.

Remove the sheeting and apply glue to the formers.
Only apply enough glue to get the formers wet.
And stop short of your marks.
Everything is downhill and the glue will want to run.
I actually had to use my finger to remove glue and touch up the dry patches.
Put the Panel in place and use masking tape to attach the panel starting in the middle and working outward.

Hold the tape strip over the panel and use the ends to pull down the sides then attach the tape ends to the edge of the formers.

STOP,
Use a scribe and poke holes thru the foam at the corners of the hatch hole from the inside.
We will have to find them later and this last step makes it easy.
Apr 27, 2019, 07:32 AM
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sparks's Avatar
Thread OP

Next sheet


After you remove the masking tape you will see that that the sheeting will have a slight wave or hump between the formers.
This defect will be dealt with when the next sheet joins it
.
Pre shape and test fit the next panel then attach it with tape to the sheet bonded to the fuselage formers.
Note that the tape is attached to the spaces in between the formers first.
This new sheet will pull down the humps as you tape the sheet to the formers.

While one sheet is drying you can work start fitting the next.
I used the brown Gorilla glue to make these bonds because of its slow curing time.
The white cures much faster but you need time to clean the foam from the seams
Apr 27, 2019, 04:00 PM
Registered User
ErcoupeEd's Avatar

Connie


Very much enjoying this build log
Now that I fixed my audio problem!
Keep up the great work Sparks!

Ed
Apr 28, 2019, 06:33 AM
RC 4 Life
sparks's Avatar
Thread OP
Once the fuselage is covered at least one third around you can remove the building fixture and stands.
Note that the stand near the rear needed the tip trimmed to clear the push rods.
All of them could have had less foam capturing the tube.
From this point on, the fuselage should be worked on a padded surface like foam rubber or a blanket to avoid dents.
At least until the first protective glass coat is applied.
Remove the center portions of the formers that you can reach for now. And finish sheeting the fuselage.
Apr 28, 2019, 06:36 AM
RC 4 Life
sparks's Avatar
Thread OP
The ends have compound curves to sharp for sheeting so we have to go to sectional construction.
Use the patterns from the plans to make blocks of foam and bond them to the ends.
Apr 28, 2019, 06:39 AM
RC 4 Life
sparks's Avatar
Thread OP

Sanding


Here we go but don’t be afraid, the sandpaper does the work.
To get started I used a razor to shave off the glue foam blowouts.
Then rough sanded the nose and Tail.
You may have noticed the sheeting was/is a little thicker than the formers.
This is intentional and allows us to remove surface defects without impacting the strength of the skin.
The sandpaper strips can be bought at automotive stores or you can simply cut a belt sander belt in two
Apr 28, 2019, 06:42 AM
RC 4 Life
sparks's Avatar
Thread OP
Holding the darn thing still while you sand the surface will be your biggest problem.
I used a blanket and sand bags to form a sort of soft hose clamp while I worked.

Hold the ends of the sandpaper strip and draw it across the surface left to right while moving it down at an angle. Hard to describe but just don’t let it make a groove in the foam and pay special attention to any high spots. Its like shining shoes f you are old enough remember that.
Apr 28, 2019, 06:25 PM
Pro Hoarder
turbonut's Avatar
Wow super nice Keith...nice work as always
Latest blog entry: In flight
Apr 28, 2019, 10:28 PM
Registered User
stacker's Avatar
Real nice work!

Cheers—Stacker


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