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Super Light Waterproof Foam Board?

foamtest

Toothpick glider kid
#1
So I haven't been too active lately because school and work but thanks to COVID-19 I have some free time so I'd like to become active for a little bit again.

Anyways I have been experimenting with removing the paper on Adams readi-board and replacing it with packing tape. I know this has been done before but I really think you guys should try it. It makes a huge difference in the final weight of the plane, and it waterproof...
20200404_112940.jpg

I started with a small scale airplane on a 2205 red bottom and it flew alright, but that was due to my cut-and-fly method of manufacturing. Without a proven air-frame it was kinda unfair for the first test but this was the first plane I've built of flown since Flite Fest last year and I wanted to make something new. I also tried a 8" prop and that caused way too much torque on the plane. It flew much better with a 6x4.5.

I made a long video on it and am interested in what you guys could do with this type of construction. How light can you make your favorite FT plane?

My next plane for this ultralight treatment is the Storch, my goal is to be able to fly it off of a red bottom on 2s with an 8" prop.
 

Hai-Lee

Old and Bold RC PILOT
#2
There are many methods of lightening your build but the builder should always bear in mind the structural strength requirements of the bird they are building. I have seen some very lightweight builds that have a very short life with either the wings or the fuselage folding and the majority of the tie the fold occurs in flight.

With the paper removed the tension resistance of the foamboard is removed and whilst the tape does add the required tension resistance the tape can migrate over time and under heavy flight loads. This migration is generally a result of the glue used on the tape allowing a little side slippage under extreme load.

It is possible to build in FB with a significant weight reduction and an increase in the structural strength but this requires the use of alternate building materials being used to reinforce the FB by enhancing both the tension and compression resistance of the foam/foamboard.

With the proper reinforcing it is possible to actually cut lightening holes in the FB as well and of course this really knocks off a lot of weight!

I reinforce using either 1mm Balsa or the use of a coat of PVA glue. TO cover the holes I resort to the use of covering filam and the results are quite good.

Just what works for me!

Have fun!
 

foamtest

Toothpick glider kid
#3
Thanks for the advice!

I was just looking for a simple way to make planes look good and fly super light, and packing tape seemed to check those two boxes so far. As you can tell I'm working on a larger, proven air frame to see how it lasts over time. I would love to build 2 storches and see what one lasts longer to weekly flights or so, but I'll be impressed if I can find the time to build one!

I also plan on using this to experiment with some 3d printed wing ribs since there is no tape on the inside of the wings I could possibly make some super interesting airfoil designs.
 

Hai-Lee

Old and Bold RC PILOT
#4
Thanks for the advice!

I was just looking for a simple way to make planes look good and fly super light, and packing tape seemed to check those two boxes so far. As you can tell I'm working on a larger, proven air frame to see how it lasts over time. I would love to build 2 storches and see what one lasts longer to weekly flights or so, but I'll be impressed if I can find the time to build one!

I also plan on using this to experiment with some 3d printed wing ribs since there is no tape on the inside of the wings I could possibly make some super interesting airfoil designs.
When running tape on the outside of the wings most people run the tape around the cord but sadly this is the weakest way. Ideally the tape should be run spanwise. If the tape needs to be run cordwise I normally run some non-stretch tape on the inside of the wing spanwise as this provides a great deal of tension resistance, (more than cordwise tape.

3D printed anything inside a foamboard wing is not as good as many make out. It is heavier unless quite thin and it is subject to fracture in a rough landing. It is possible to fly for quite a long time with fractured internals until on one flight it all just collapses or explodes into foamboard confetti.

Test everything to failure before putting it inside a wing that you cannot inspect regularly.

Otherwise have fun!
 

Bricks

Well-known member
#5
To add strengh, less weight and rigidness strip the paper and cover using news print and glue watered down amazing how much stronger the foam board is after this treatment.
 

foamtest

Toothpick glider kid
#6
3D printed anything inside a foamboard wing is not as good as many make out. It is heavier unless quite thin and it is subject to fracture in a rough landing. It is possible to fly for quite a long time with fractured internals until on one flight it all just collapses or explodes into foamboard confetti.
That is a good point. I might just use the 3d printer to make a template and cut that out of foam board.
 
#7
What's your method for removing the paper off of the adams board? I haven't built in a while, but I used to just peel one side off and go. I tried to do that last week and had the worst time getting the paper off.
 

Ryan O.

Well-known member
#8
There are many methods of lightening your build but the builder should always bear in mind the structural strength requirements of the bird they are building. I have seen some very lightweight builds that have a very short life with either the wings or the fuselage folding and the majority of the tie the fold occurs in flight.

With the paper removed the tension resistance of the foamboard is removed and whilst the tape does add the required tension resistance the tape can migrate over time and under heavy flight loads. This migration is generally a result of the glue used on the tape allowing a little side slippage under extreme load.

It is possible to build in FB with a significant weight reduction and an increase in the structural strength but this requires the use of alternate building materials being used to reinforce the FB by enhancing both the tension and compression resistance of the foam/foamboard.

With the proper reinforcing it is possible to actually cut lightening holes in the FB as well and of course this really knocks off a lot of weight!

I reinforce using either 1mm Balsa or the use of a coat of PVA glue. TO cover the holes I resort to the use of covering filam and the results are quite good.

Just what works for me!

Have fun!
When removing paper, but still leaving some left, I like to do it on the inside for non structural pieces only. One method is to score a circle or triangle, and only cut through the paper. Then you peel off the triangle/circle, and you can lighten up an area by doing that on the inside of the airplane.
 

foamtest

Toothpick glider kid
#9
What's your method for removing the paper off of the adams board? I haven't built in a while, but I used to just peel one side off and go. I tried to do that last week and had the worst time getting the paper off.
I haven't had too many issues with getting it off, my stockpile is a year old though and could be different from the formula they use now. I did notice that there is a certain angle that works best. Sometimes it is just difficult for no reason.