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Oct 06, 2008, 01:50 PM
Lee
Lee
PERFECT LANDING !!!
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I washed a Snowball the other day and it soaked up 5 oz of water and took 3 days to dry. I forgot about the water problems with the EPP we had last year on snow. We were flying the Roswells and they would slowly soak up water We would get warm planes out of our can and set them on the snow and their center of gravity would change as they soaked up water.

I have not flown raw foam planes off water before. Those of you who have help me out ..... Is there a sealant that will seal both the foams so that either can be used?
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Oct 06, 2008, 02:29 PM
AKA Don
I've not tested EPP, but Depron and blue core FF did not soak up any water in my testing.

If the basic material soakes up water I wuold think only completely covering with a film would seal it up. Even then I would worry about seams and "dents".
Oct 06, 2008, 03:09 PM
Registered User
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I haven't tried blue core FF, but blue foam in the 1" sheets does soak water, slower than others, but if you rest in the water for 5 minutes, you will have a loooong take off.

I have used water-based paint to seal the foam on boats, works on blue, pink and styrofoam, but the expanded bead sucks up so much that it would end up heavy. That is a shame because this foam is the most rigid for the least weight.

When we talk planes instead of boats, I worry about the weight of the paint. So until I experiment with FFF as referenced by Don, I stick with Depron, and all its difficulties obtaining it.
Oct 06, 2008, 03:27 PM
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My problem with Depron is making floats, they have to be built up and I never get them sealed good enough. I have resigned myself to drain holes so the water can run out when you stand it on its tail.

Pardon the shouting, but DOES ANYBODY HAVE AN ANSWER?
Oct 06, 2008, 05:17 PM
AKA Don
My test on the orig. (skin on two sides) blue FF was 20 min. submerged in water. The skin was on but the edges were bare foam. Then remove from the water, dry with a towel and weigh on a scale with 0.1 g least count. No gain at all.
Oct 06, 2008, 05:26 PM
Registered User
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That sounds very encouraging. My tests on various foam, as I recall, would double in weight in about 1/2 hour. Blue foam was the slowest to gain weight, EPS in about 10 minutes.
Oct 06, 2008, 11:28 PM
Lee
Lee
PERFECT LANDING !!!
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The EPP by far is the worst foam I know of when it comes to acting like a sponge. It soaks up lots of water fast. It also drys fast. It is the best foam without question for an indestructable ATV plane. I'll have to build different planes for different places and times of year. Most of the year our weather is pretty good so the EPP is still the foam of choice.

I plan on doing some testing with paint to see if it helps but the paint could also help to hold the water in so it can't get out. I wanted the Snowball to fly of snow. I'm going to cut a few Snowballs out of blue foam I to have laying around and do some seaplane tests.

I think I will hop over to wattflyer and see what Larry thinks of the different foams where he does so much off water with untreated foam.
Last edited by Lee; Oct 08, 2008 at 04:57 AM.
Oct 07, 2008, 12:10 AM
Lee
Lee
PERFECT LANDING !!!
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Ask and ye shall receive. Here is Larry's insight. Thanks Larry!!!!

Hi Lee, I see there is some discussion of water and foams on the Snowball thread.

I did some tests last winter on water absorbsion on various foams.

I tested 1/2" and 1" blue foam and 2" pink foam, Depron, Pool Noodle foam (similar to EPP but not the same) as well as plain old ice chest type beaded styrofoam.

First, I weighed all the peices dry.

Next I got a "damp" weight to simulate what it would be like when flying off water under typical conditions.

I dunked them completely under water for about 2 seconds, took them out of the water and shook off all the excess water.

I did NOT dry them off in any other way. This was the "damp" weight which shows how much water sticks due to splashing etc but without big drops sitting on the foam.

Then finally I put all the peices in a bath tub of cold water and weighed them down so they were completely submerged. I left them in for about 4 hours.

After soaking, I removed them and again shook off all the excess water as in the "damp" test. This final weigh should have shown any water soaking in over time.

The Depron and the blue and pink building insulation weighed exactly the same after soaking as they did after a quick dunk.

They absorbed no excess water after a 4 hour soak.

The Pool Noodle foam weighed very very slightly more than the damp test but not a significant amount.

The beaded styrofoam absorbed about 10-12% of its weight in water after soaking 4 hours.

I have also done some testing of the added weight of water that "splashes" and clings to the plane. In other words with lots of droplets clinging. On a typical Capricorn it can amount to several ounces of excess weight and most all of the added weight is behind the CG. I think thats more worrysome than absorbing water.


Larry
Oct 07, 2008, 02:28 AM
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Lee,

I will repeat my tests, but I recall clearly that my beaded styrofoam floats for a modified Miss Hangar One, which were only two ounces, became 4 ounces after less than 1/2 hour.
My floats were cut and sanded, possibly exposing the core to the water more than otherwise.
I changed to pink, grumbling about the extra couple ounces (dry), and found it got soaked too, so I made the floats in blue, really heavy, and it did resist water better, but had to be hollowed out to be light. They eventually did soak up water too, so I changed to Depron.
Another factor, the plane is warm when it goes on the cool water, this would cause the air within to shring, drawing in water.

Oddly, I may be unique with my flying of the MHO, and now the Capricorn, as I fly exclusively off the lake, never off land.

I will post my results when I retest. Thanks for your test, Lee, I appreciate the effort.
Oct 08, 2008, 05:04 AM
Lee
Lee
PERFECT LANDING !!!
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I have gone back to posts 6-10 and updated and added to the information. I hope this helps. Please ask questions or share information and I will correct or update as needed.

Lee
Oct 08, 2008, 06:30 AM
Crash Master
Gene Bond's Avatar
IMO, XPE (extruded polyethelene / Noodle Foam) is best for floats, as it's a closed cell, break-proof foam. There's few places to find it, however... mostly from computer and periferal packing. It comes pre-laminated out of 1/4 or so layers.

Alternatively, I've had very good luck covering EPS (beer cooler foam) and XPS (Depron, BluCor, etc) with packing tape, Econocote, or Doculam.

For skid-proofing, I've used pieces of milk jug, glued to the bottom.
Oct 08, 2008, 08:02 AM
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Lee,

Trying to get caught up on this thread, it is growing faster than I can read, but I am a little slow, as I savor every word. By the way you almost never make a spelling error, something I admire, but I certainly don't compare others to that standard.

Reading your post 41, I think you have a very healthy attitude about giving people credit for the origin of many of your ideas. I have always thought that an inventor is the "node" where two or more ideas intersect. How is that for abstract?

Without inventors such as yourself, we wouldn't enjoy the advancements we do. The government put together the copyright and patent laws to allow inventors to protect themselves from loss of revenue when releasing their inventions to the public.

I think you are helping to protect from loss of credit when releasing their inventions to the public, something the gov't didn't accomplish! I also feel you would never interfere with any revenue to the inventor, in fact your improvements are available to the inventor too, you may actually enhance their commercial activities!

So big thanks to you, and keep up the gud speling. Please anyone don't be offended by my love of good spelling, there are many reasons, including area of the world... My spelling would be horrible in England (Bloody awful?) ha ha
Last edited by dbacon; Oct 08, 2008 at 03:55 PM.
Oct 08, 2008, 08:40 AM
Registered User
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I guess I have to go back and test the foam for water absorption. Larry's test to see water "cling" was one I didn't do, and that surely caused me to reach inaccurate conclusions. Maybe this weekend... I will post results in the next block available at that time, and come back here to post that one's number here --->____
Man, I would love to discover that pink doesn't suck water, I love pink.
Oct 10, 2008, 09:36 AM
Registered User

confused


I cut my circle out of fanfold at slightly over 23" because i was gettng close to the 24" edge of the fanfold. my wings are 6" each side.

Confusion part.
cut the floats from epp the dimensions you specify 1 1/2"w x 12"L. my floats are glued to the edge of the wings. Looking at your pics the floats seem to be further out. I only have 8 1/2" between the inside of the floats.

I measured 6" back from the front center of the circle for cg and drew a horizontal line across to the wings. I then put the floats on with step at the 6" line and they stick out in the front just over 7" which seem quite long in the front. I think I must have some measurements wrong. Help.

Here are pics of what I have gotten done.
Last edited by wowsers; Oct 10, 2008 at 01:20 PM.
Oct 10, 2008, 10:26 AM
Lee
Lee
PERFECT LANDING !!!
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Quote:
Originally Posted by wowsers
I cut my circle out of fanfold at slightly over 23" because i was gettng close to the 24" edge of the fanfold. my wings are 6" each side.

Confusion part.
cut the floats from epp the dimensions you specify 1 1/2"w x 12"L. my floats are glued to the edge of the wings. Looking at your pics the floats seem to be further out. I only have 8 1/2" between the inside of the floats.

I measured 6" back from the front center of the circle for cg and drew a horizontal line across to the wings. I then put the floats on with step at the 6" line and they stick out in the front just over 7" which seem quite long in the front. I think I must have some measurements wrong. Help.
Can you please post some pictures and let's have a look.

I have been playing with the float and motor/radio mounting designs this week and have several variations almost ready to fly but, rare as it may be, we have a major storm coming in and I won't get a chance for calm air till next week.

My thought is this. The Snowball has plenty of prop clearance until the plane rocks forward on the front angle of the float during landings. My latest float is only 9" long and the back edge of the float is at CG, or 6" back, and the front of the float pokes out just longer than the prop.

The bottom is flatter that the angled float we did before and the front of the float has a steeper angle for only 3" of the front.

I just took some pictures of the new "Top Secret" variations. I'll have them posted in a few minutes.

My son and I are trying to reduce weight


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