JART Build ie HOW to vacuum your bags ie HOW to laminate foam wings

[thenated0g]

Very simple and easy to use. Its a cherry switch basically. You can choose normally open or closed just like any other cherry switch. No electricity is needed to run the switch, it is a mechanical switch. Meaning it uses the negative pressure or lack of to activate the cherry switch. It can handle up to around 5amps thru the cherry switch itself so if you have more than that you also need a relay.

In my case i cut the positive 12v line that was going to my pump and placed this right in the middle of it, just like an on/off toggle switch would go. Than its just as simple as running a vacuum line from the other end of the switch to your vacuum system to monitor it just like your mercury guage.

IT has an analog dial you adjust to get the vacuum you want and the "range" it drops down to is not adjustable. At the range im working at its about 2" of mercury drop before it activates.

You can see the dial nob on the left of the pic below.

https://store.acpsales.com/products/3297/vacuum-switch

 

[thenated0g]

Tell us more about the automatic switch. Where did you get it.? Is it fixed or can you adjust the on & off points?
Any trouble with things moving around as you pulled the vacuum?

Just realized i didnt answer your second question. No nothing moved around. I pulled almost all the air out and stopped the pump, than i arranged the wing in the beds and weighted it down. Than pulled full vacuum.

 

[thenated0g]

I had debated doing the horizontal stabilizer/elevator as two seperate pieces or a single piece, but after seeing how strong the wing was after getting laminated I realized i really want that strength of a single piece in the tail.

So i first leveled and glued the two beds together and than used white GG to glue the two wing cores together.

The possible bad things here are that this has some compound curves. It is high in the center going down towards each wing tip. It also needs to go around the LE and TE curves. Guess we will see what happens.

Next i need to trace the shape on to two pieces of balsa and start bagging.

 

[thenated0g]

Horizontal Stabilizer Bagged.

 

[thenated0g]

 

[thenated0g]

Back in a previous post i list the steps i did in this video:
https://forum.flitetest.com/index.p...-how-to-laminate-foam-wings.55426/post-434401

 

[thenated0g]

Heres a quick 1 minute version of the above video:

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[thenated0g]

Did a temporary "functional", ie not pretty, stand for the vacuum pump setup. Just getting things in place to see how i like using it. Added an on/off switch. Hot glued the pump to the wood which works surprisingly well. Red double sided tape the power supply to the wood. I definately need to replace the 1/4 stranded tubing that connects the system to the bag. It is very rigid and hard to use. I have some 1/8 ID black tubing that should work well and move around much easier.

Still needing to be added is a vacuum storage tank of some kind. This will allow me to prime the system ahead of time and than quickly deflate a bag and will increase the amount of time in between pump runs while doing a job.

 

[thenated0g]

Been playing around with color designs. I really like the finished balsa look but don't want to spend a lot of time adding layers and sanding, trying to fill in the grain, so i think i will just do some light stain on the bottom to get the stripes for orientation, do a light coat of minwax (mainly to bring out the color of the wood), and than wrap it in clear iron on laminate. The fuselage I will just cover in some Appliance enamel white paint.

 

[thenated0g]

All wing surfaces bagged. Lots of little work on them to get it ready to attach to the fuselage.

 

[thenated0g]

some years later .....
Since those last posts i picked up a LEG Jart kit (EPP version) and put it together and had an amazing flight in 21mph+ winds.

This got me motivated to get this old project finished.

I finally finished the fuselage. I filled/sanded/filled repeat. Painted several coats of paint until the final color:
I used pink as primer as my grey ran out.


I wasn't happy with the wings and tail so i recut them and decided to cover them with 1/16 ply. This is crazy thick but i want a really heavy jart as i already have a "lighter" wind jart now. What's cool is this foam was gifted to me by a surfboard maker that follows me on Instagram and new i was coming down to his part of the California for a slope soaring event at Watsonville, ca.


Heres the horizontal stab with some kevlar for a hinge before vacuum bagging


Wings before and after getting vacuum bagged. Even designed up a servo holder for the wings. Went with several coats of polycrylic for covering.
View attachment

And some bench flying:

 

[thenated0g]

Oh yeah, here is the updated graphics/design i am going for

 

[thenated0g]

video of me bagging the right wing:

 

[thenated0g]

Been doing so many pw51 planks that i didnt even think about it and did a bottom hinge. Oh well


I picked up a Jart fuse from Thomas down in san diego and this morning realized how much time that premade hatch is going to save me now as i can just trace it on my scratch build.

 

[thenated0g]

 

[thenated0g]

Wings epoxied together. I did some epoxy and filler in between. Then one layer of 6oz s glass on each side with some peel ply for a nice rough surface to glue to the fuse later.

 

[thenated0g]

Last night i cut out the wing and tail holes. I didnt want to slide the wing all the way thru as its pretty tight but i did want to see what it looked like.

 

[cyclone3350]

Last night i cut out the wing and tail holes. I didnt want to slide the wing all the way thru as its pretty tight but i did want to see what it looked like.
View attachment 230743 View attachment 230744

I've been considering vacuum bagging & was looking for some ideas as to how to do it. Thanks for posting. Awesome project U got there.

 

[thenated0g]

I would recommend looking around in the rcgroups composites section.
https://www.rcgroups.com/composites-fabrication-210/?daysprune=-1

 

[thenated0g]

https://youtube.com/shorts/1d7S98gMjO8?feature=share