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Jun 27, 2016, 09:47 AM
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1:6 Nemere foam/glass


I was completely impressed by Joe Yap's small scale glider builds and decided to try it for myself to see how hard it would be for someone with no experience with this technique.

The immediate goal is to end up with one glass slipper and one vintage sailplane spanning 3-4m with a motor in the nose for hand launching on a comparatively small field.

For the glass slipper I've jumped on the end of Joe's excellent "Little Duo Discus" thread in hopes of getting others to give it a go for themselves.

Here is the progress so far on the 1:6 Nemere at 3.33 meter span. The black after the profile is cut.


The rough blank.


Sureformed and sanded to shape. One side cut into section in preperation for hollowing.


The templates used for hollowing with a hotwire.


Humpty Dumpty together again ready to be smoothed for the application of a layer of glass on the inside.


I'll probably do this one with just glass, paint and maybe stain on the outside so I can see if the overall design works.

Here is some brainstorming for future consideration though. Please add suggestions or recommend changes.

1) Hollow foam and add one layer of glass to inside. Put one layer of glass over the outside of the foam. Use balsa or veneer panels to cover the first layer of glass. Finish as desired and add another layer of glass over the balsa or veneer.

2) Solid or quickly hollowed foam plug not smoothed or glassed inside. Add one or more layer(s) of glass then balsa or veneer, then a layer of glass over the outside. Dissolve foam plug.

Another option I wondered about is to make a 2 piece mold from a finished fuselage or plug. Cover each half of the mold with a vented plate. Use spray foam to make another 2 piece foam plug without having to shape it from scratch.
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Jun 28, 2016, 02:05 AM
Aerotow and sloping Holland
MaartenX's Avatar
Nice project.

As for a Glass fuse I would suggest to use the lost mould method.
You can see an example here: https://www.rcgroups.com/forums/show...2504256&page=5

There is more info on this building method on my website too: www.pjmodelclassics.weebly.com

Good luck, Maarten
Aug 01, 2016, 10:06 AM
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A little progress has been made. The inside is now glassed with one layer of 1.2oz cloth. The easiest method for the concave surface was to:
1) Brush a coat of resin on the foam
2) Wet out the cloth on wax paper
3) Apply cloth and smooth with an aluminum roller and squeegee.

Please post suggestions if there are better methods as I'm learning on the fly.

The foam halves weighed 30 grams each before glassing, 75 grams each after. The fuselage is about 47.5"/1200mm long. I plan to apply one layer of 2.6oz (need to order it) or 6oz (have tons on hand) covered by one layer of 1.2oz on the outside. Any thoughts?

Aug 04, 2016, 06:55 PM
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Love the Nemere


I'm subscribed, I love the Nemere such a beautiful machine, here's a video of my 5m one I built about 24 years ago, this is its test flight, every time I watch it I feel the need to build another, anyway this model was built using the lost foam method and all the wood panels on the fuselage are actually iron on veneer pieces, I still have the remains of the back half of this fuselage and the veneer is still stuck down the the glass fine,
I'm enjoying your build I hope you enjoy the video,
Regards
Alexis https://www.youtube.com/shared?ci=iKseTfCL95I
Aug 04, 2016, 10:57 PM
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owlsabie's Avatar
Great video of a beautiful glider!
Aug 05, 2016, 07:49 AM
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Alexis,

Thanks for posting that. I hope you will build another. I hope to cut the wing cores this weekend. Still trying to figure out how to do the templates because of the way the aileron extends back from the trailing edge.
Aug 05, 2016, 07:59 AM
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Quote:
Originally Posted by bcarter1234
Alexis,

Thanks for posting that. I hope you will build another. I hope to cut the wing cores this weekend. Still trying to figure out how to do the templates because of the way the aileron extends back from the trailing edge.
Thanks for the kind worda, When I built mine I did it with built up wings as you can see, but what I did was used the stacked rib method for the ribs and the ailerons are just a taper from the wing thickness at the hinge point back to the aileron trailing edge, from all my research I'm confident that would be pretty close and as you can see it certainly flew well,I'm watching your build with interest perhaps after my two current projects are flying I might have to think more seriously about a new Nemere
Last edited by Alexis Scott; Aug 05, 2016 at 06:28 PM.
Aug 05, 2016, 08:07 AM
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As a little side note in 5 days time it will be 80 years since Lajos Rotters' record pre war designated goal flight
Last edited by Alexis Scott; Aug 05, 2016 at 06:41 PM.
Aug 05, 2016, 04:52 PM
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Thread OP
Thanks for the tip on the wing shape. That helps me to visualize what needs to be done. I was considering carving a small wing half from a piece of foam just to understand the shape required. Finishing the wing at the aileron hinge line and then adding the remaining section to the back should work out fine.

My first wing will have solid foam cores until I see if I can get it to fly well. If so I may do a built up wing or a mix of foam and wood to allow the open bays for the sun to shine through.

SPasierb has a 5m(?) version and when it is flying the wings glow like they have a light source inside them. With his flying skill they also seem to have a source of lightness in them as well. ;-)
Aug 05, 2016, 07:43 PM
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mlachow's Avatar
Quote:
Originally Posted by bcarter1234
A little progress has been made. The inside is now glassed with one layer of 1.2oz cloth. The easiest method for the concave surface was to:
1) Brush a coat of resin on the foam
2) Wet out the cloth on wax paper
3) Apply cloth and smooth with an aluminum roller and squeegee.

Please post suggestions if there are better methods as I'm learning on the fly.

The foam halves weighed 30 grams each before glassing, 75 grams each after. The fuselage is about 47.5"/1200mm long. I plan to apply one layer of 2.6oz (need to order it) or 6oz (have tons on hand) covered by one layer of 1.2oz on the outside. Any thoughts?


Just do multiple 1.2 layers if you have that. Two 0-90 and one on the bias. You could add an extra layer up front. The light glass might take less epoxy
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Aug 06, 2016, 02:36 PM
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mlachow,

Thanks for the suggestion on the layup schedule. According to UPS as of Tuesday I'll have plenty of the 1.2oz on hand.
Sep 25, 2016, 08:19 PM
IT'S NOSE HEAVY!!!!
cityevader's Avatar
Late to the show, but I want to say that I like it!
With such a distance between inner/outer skins, it should be super stiff!

Looks just like my wee Multiplex Fox FF conversion with hollowed out fuse.

I assume you'll seam the two halves internally first, then final sand the external seam before external glass?
Sep 25, 2016, 08:46 PM
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Yes that is the plan. This project will be delayed a bit as I decided to try more traditional lost foam fuse first. It will give me a chance to compare the two methods.
Sep 25, 2016, 09:01 PM
IT'S NOSE HEAVY!!!!
cityevader's Avatar
Well...it would be silly to abandon effort so far into it!

For sure, finish the current project WHILE doing the lost foam version.


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