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Backyard Blue Foam Glider Thoughts

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Backyard Blue Foam Glider Thoughts

Old 12-12-2005, 03:45 PM
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GB57
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Default Backyard Blue Foam Glider Thoughts

I am thinking about building a small (32-36 in.) very simple (rudder-elevator) blue fan fold foam glider for backyard flying. I plan on a simple under cambered wing. Likely would use a "weak" hi-start or just hand launch and soar in the wind coming over my roof on light wind days. I have many years of slope, hi-start and electric powered glider flight so am not new to gliders. Just looking for a simple, fun project. Short flights will be fine for this project. I have Rx, 2 servos and NiMH battery pack that weigh just under an ounce. The blue foam glider should weigh in at or under 3 oz AUW. I have searched the sailplane sight for this subject and have come up empty handed. Are there any thoughts on this or does anyone know of forums on this subject?
Old 12-12-2005, 04:08 PM
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OLDNRINKLED
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Default RE: Backyard Blue Foam Glider Thoughts

I PONDERED THE BLUE FOAM AND BOUGHT A SHEET FROM LOWE'S. I THINK THIS IS THE FOAM YOU REFER TO. IT IS EASILY SHAPED AND SANDED, VERY LIGHT AND SHOWS PROMISE. I WHITTLED AN AQUILA FUSELAGE OUT OF THE STUFF AND IT WEIGHED ALMOST NOTHING ON MY SCALES. USING SPRUCE STRINGERS FOR THE SIDES AND A LITTLE WISDOM FOUND FROM KITS IN THE PAST I THINK YOU COULD BUILD A STANDARD CLASS SAILPLANE OUT OF THIS STUFF AND NEVER EVEN COME CLOSE TO 16 OUNCES. BUILDING EVERYTHING OUT OF SUPER LIGHT MATERIALS AND USING A PARKFLYER MOTOR, ESC AND RADIO LEFT OVER FROM AN OLDER PROJECT I THINK YOU MIGHT HAVE A NEAT CALM DAY FLYER. I HOPE TO FIND OUT THIS SPRING BECAUSE I HAVE JUST THE PROJECT STARTED. FOR THOSE ENGINEERS OUT THERE PLEASE DONT WRITE AND TELL ME ABOUT CARBON FIBER, STRENGTH, TECHNICAL MUMBO JUMBO YADA YADA. I THINK THIS GUY IS JUST LOOKING FOR FUN IN HIS BACK YARD SAME AS ME. HAPPY EXPERIMENTING. REGARDS DUANE.
Old 12-12-2005, 04:18 PM
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Default RE: Backyard Blue Foam Glider Thoughts

What you gents are up to sounds real interesting to me.
Could you please elaborate on the "blue fan-fold foam" from Lowe's that weighs nothing - or less, please? Does it have a name that the odd bod in Lowe's would recognise?
Hope to hear more of the project.
Cheers

Old 12-12-2005, 06:29 PM
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Default RE: Backyard Blue Foam Glider Thoughts

BLUE FOAM
Old 12-12-2005, 06:46 PM
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Default RE: Backyard Blue Foam Glider Thoughts

The blue foam I am referring to is made by Dow Chemical and has the name Styrofit on the foam. I paid about $10.00 for a 4 x 8 , 2 inch thick sheet. To say it has no weight is crazy, however when used as a fuselage and wing, stab etc it has so little voulme used that the weight is negligable. It sands well, saws well and doesnt bead up when cut or sanded like some white foam I have worked with. Fourty years ago I had a dear friend who played with foam sailplanes and kitted a V 8 and a Fournier RF4 both made of white foam. Very little bracing internally and the radio was a pulse rudder only by Airtrol of Adrian for those of you who remember. The last time I saw the V8 was about 1200 feet headed east south east of the field. We chased it with a car and never found it. WHAT A THERMAL ! There ia great potential for fun aircraft of this variety, I have done it and seen it, years ago. With todays glues and materials I hope to experiment with this construction again. Small electric motors and micro radio's make this exciting to me and I hope others. I have a pix of a fuselage I sanded in about 20 minutes time. I hope it shows the potential of this material. Regards Duane
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Old 12-13-2005, 04:48 AM
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kuga220
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Default RE: Backyard Blue Foam Glider Thoughts

http://www.charlesriverrc.org/articl..._apogeehlg.htm
Old 12-13-2005, 08:57 AM
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da Rock
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Default RE: Backyard Blue Foam Glider Thoughts

GB57,
To get back to your question....
Fan fold foam makes good "flat" wings. And when they're cambered a little, they're even better for some applications. They're used in park flyers to great success as is obvious. But one detail about those park flyers is very often given short shrift. They don't glide.

When the power is off, they often come down like a falling leaf. Some do come down like a falling leaf that's got a heavy stem, but the "glide" of those still ain't like no thermal glider we ever hi-started.

I've wanted to dink together a pink foam rc glider since I discovered insulating foam for myself some months ago, but haven't taken the time to give it a try. I'm just getting back into RC after almost 20 years layoff and been too busy putting receivers and battery packs into my Sagitta, OlyII, etc and sticking together power ARFs (got a .50 size Corsair that's about halfway across the US in a UPS truck right now).

I built competition CL stunters for many years, and RC gliders for about as many years. I used to carry a small Triner Scale into the LHSs every week or so to weight out their new balsa shipments looking for the really good contest balsa. Contest balsa is usually 4-6 lb/sq foot. The foams are about half that but vary. They vary more on the mfg side, since the production process is extremely consistent. And with all that past experience tells me that a solid foam structure is going to be light, very light. And probably too light to glide unless it's carrying appropriately "heavy" rc equipment or ballast. And when that happens, the wing is going to need to be more than just fan-fold flat foam. Also, the flat wing profiles, even when cambered tend to have L/D curves that peak REAL CLOSE to 0 AOA. So the flat fan-fold has a couple of strikes against it... maybe.

What I figured was that for the tiny thing to be useful, it'd have to be heavy enough to at least penetrate enough to glide on calm days, and probably have wing loading enough to penetrate on days with light-moderate breeze. And that'd suggest to me that the wing would probably be big enough and thick enough to need to be hotwired out of something like my 3/4" foam board. I'm figuring to split it spanwise where a spar would go, and glue it back together with a layer of silkspan or such for a spar. See if that'll hold up to a "micro hi-start" and go from there.

A bunch of people have made micro, indoor RC models, so getting the thing small enough isn't going to be a challenge. But getting the right wing loading is going to be.
Old 12-13-2005, 09:07 AM
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Default RE: Backyard Blue Foam Glider Thoughts

Here is a 1/4" blue foam sheet "foamy" our club got together in the local hobby shop one night and built about 10 of them.
Mine all up weight is just under 13oz. It has a carbon tube leading edge spar and some flat carbon on the fuse side edges.
It uses an Esskay 400XT that Hobby Lobby is having on sale now for around $19 and a Thunderbird 18 ESC. 3S700mah LiPo, 4 HiTech HS55 servos and an old, old RCD 7 channel receiver I took the case off of to save weight. It was a full size dual conversion receiver.
They are right about not gliding in the sense that when you land power off and try to flare it just plops down.
Otherwise it flys great!
JLK
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Old 12-13-2005, 06:38 PM
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Default RE: Backyard Blue Foam Glider Thoughts

I made a foam wing out of a 20" X 30" foam board I bought at Walmart. The board cost me under $2. I soaked the board in the tub for 3hrs then peeled off the paper on both sides. I spray glued the template straight to the foam and cut out all the pieces. I put a couple pieces of strapping tape on the bottom and then covered the top with some clear packing tape. it is very light and cheap to make. I have sloped it in 3 mph wind. If you started with a sheet of 5mm or 1/4" depron it would go even faster. I have ground pounded it and it still flies.
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Old 12-13-2005, 07:13 PM
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Default RE: Backyard Blue Foam Glider Thoughts

I would suggest using Ailerons for a Backyard type of glider. Depending on how much Dihedral you use, if not enough, it will not turn quick enough in a small area. It'll be better if it was a PARKFLYER glider.

Or instead of RE, why not just do AE, Aileron and elevator. On such a small plane, you don't need rudder.

Just like most glider pilots say,, Rudder is not needed if the plane is under 60" span.

-Tomi
Old 12-13-2005, 07:53 PM
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da Rock
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Default RE: Backyard Blue Foam Glider Thoughts

BTW, thermal flying gliders spend a bunch of their time hunting for thermals. The smaller they are, the more that hunting looks like a short trip from the top of the towline to the landing. The thermal ships really have to cover some ground to find lift and the larger they are, the more ground they cover and vice versa.

A little sucker really seems more suited (or less suicidal) for the slopes. The reason I've not sliced mine out of that foam resting in the corner is because I got no slopes anywhere near. And I really can't see the little jewel having anything like a decent L/D enough to be a good hunter.
Old 12-13-2005, 09:35 PM
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Default RE: Backyard Blue Foam Glider Thoughts

That foam board from Walmart has a depron foam core. Lighter than fan fold foam (blue foam).

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