SLUM CAT... From Dollar Tree Foam Board. Revisited! - RC Groups
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Jul 29, 2009, 02:09 PM
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RWCLOUD's Avatar

SLUM CAT... From Dollar Tree Foam Board. Revisited!

With Blu Cor and PB3 no longer available around here, and with the price of Depron after you add shipping, Dallor Tree Foam board is about the only choice for quick and dirty projects .

So I thought I'd start trying this stuff out. Its heaver than other Foams with the paper on and too weak with it off. I'm of the school that " Bigger flies better"

I think that the way to get around the weight issue is to build enough wing area to support the extra weight.

This is my first serious attempt at a good flying Dollar Tree foam board, I call it the Slum Cat, because it was made from stuff laying around. Some specs: W/S 30 inches, 1.77 sq feet of wing area. Length 35 7/8 inches. All up weight is 16.3 ounces. And yes it does fly very nice ! 3/4 throttle and let go of her and shes off and flying hands off until a gust of wind changes course.

Power is an old BP 2410-12 motor, with an APC 8x3.8 prop. 2 HXT900 servos and 1 HS 55. Electron 6 receiver. Rino 1050 mah 3s 30c battery. Silver series 25 amp esc. Hey it was laying around so why not use it?

I've always wanted a " Cat" so I decided to use the TLAR approach and built a chuckie. The Chuckie flew great so I enlarged it 300% and this was the result. I gotta say that Dollar Tree foam board is ugly unpainted ! But you can't mask it off to spray paint it so I brushed on some Acrylic paint from wall Mart. I even tried to do some weathering on the panel lines, but that didn't work to well, but hey it gives it some character ! The paint that you see here added .7 ounces. Not to bad.

Anyway If your thinking of using this type of foam hope this might help you out
Last edited by RWCLOUD; Nov 20, 2010 at 08:03 PM. Reason: spelling
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Jul 29, 2009, 03:10 PM
cmelton11's Avatar
Do you have any plans for this plane? I would love to see them. I have tons of that ole Dollar tree foam.
Jul 29, 2009, 04:04 PM
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RWCLOUD's Avatar
Sorry not at present. Maybe if there is enough interest I could do some , but it would be a couple of weeks.

But really, it shouldn't fly much different that all the other "Cats"
Jul 30, 2009, 04:39 AM
To drive or to fly......BOTH!!
FresnoJay's Avatar
RW, She looks sweet with the paint on her. Really looks the part and has that unique look to it. Similar to the "Cat" family but just different enough to call your own .

Jul 30, 2009, 12:24 PM
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RWCLOUD's Avatar
Thanks Jason!

Forgot to mention : This has " Drooped" leading edges. The leading edge is drooped down the thickness of the foam, about 1 inch back at the root and 1/2 inch back at the tip. Very easy to do , just cut the foam about 2/3 through from the bottom, run a #1 Philips screwdriver through the slot and bend up. I used Gorilla glue to glue it and masking tape to hold it in place while drying.

Drooping the leading edge greatly enhances the glide and stiffens the wing. Much lighter than KFM and very easy to do. But does it hurt the top speed??? NOT in the slightest!!! No more KFM's for me this is way more gooder!!!

Blue Skies...................R Dub
Jul 30, 2009, 03:10 PM
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43851E's Avatar

6mm paper backed foam board

Great stuff. 30" x 24" cost= 1.99 at hobby lobby here in Texas. I've built a home designed 30" wing span YAK. Will maiden Saturday. Pics to follow. Still in the detailing phase. Since It's been awhile since I've flown I thought that I needed something that would be cheap to build & repair, PLUS I'm thinking it will be sturdy enough to withstand most of my cartwheels & wingdigs. The weight is 16Oz, with the current setup, it will takeoff out of my hand.

The curved leading edge, that is a really cool idea. Just cut along the leading edge, right? Then score it with a small tip, you recommend a #1 phillips, then gorrilla glue with tape. With this plane is the first time I have ever tried that type of adhesive. Expands like crazy, but I can sand it off when well dryed with a dremal sanding drum on slow speed. Never really wanted to fly a flat wing. I got thinking, why not just mount it into a curved slot on the fuse? Got my curved wing. Across 10", I was able to curve it 2" with no folding. It straightens up out at the wing ends, but ends up with a compound foil. Pictures coming.

I have a F-22 also that has been 50% completed, but that thing will be way to fast for any park flying. Steve Shumake *JetSet44* designs. Check it out, well made pland. He is even in kit production. Other plans

Jul 30, 2009, 04:36 PM
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Its not curved, just a straight fold, about the thickness of the foam. On the first plane that I tried this on it was already flying, after drooping the leading edge , I was surprised to see no trim changes, needing a lot longer landing approach and higher speed!!!

Gorilla Glue, just use a small amount. Barely coat the surface with a thin coat. On depron, I mask off areas that I don't want glue then after about 20 minutes pull the tape and glue off. makes a clean line!

Blue Skies.................R Dub
Jul 30, 2009, 09:56 PM
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43851E's Avatar

Curved wing out of "sturdy board"

Simply insert into a curved slot..I will work on the leading edges like you showed me. Something needed to be done to this area. Perfect idea.
Thx R Dub

Jul 30, 2009, 09:59 PM
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RWCLOUD's Avatar
OK since we're slumin' here , I rewound one of the 3 Bp2410-12 motors that FresnoJay gave me. Went with 4 strands of 30 gauge wire , 8 turns and in DRLK.

Old motor 9330 rpm with 8x3.8 prop new motor 15780 rpm with 5.5x4.5 prop. And they both pull 11.8 amps. 34.2 mph vs 68.5 mph prop pitch speed.

Too windy to tell much right now about how it flies , 15 mph gusting to 20 but hey I just had to try anyway Turbulence kills here more than the wind ! But yeah its faster, and they big surprise was the landing, that big prop makes a pretty good brake, where as the small does not !! Had to make 2 approaches and still land HOT !!!

Since this bird has all square edges I don't expect a whole lot in speed anyway, but it was fun playing around with the motor!

Blue Skies.................R Dub
Jul 30, 2009, 10:05 PM
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Well you have a curved wing already, no need to droop the leading edge ! Just leave it alone, it will be fine!

Blue Skies.................R Dub
Jul 31, 2009, 08:07 PM
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43851E's Avatar

You think?

I was thinking that I needed some sort of leading edge treatment to at least protect it from dings & dents.

Fly'in in Fresno. I'm from CA. Been gone too long. Got an old friend in your town too. Last name Dunks. Did some tooling contract work in Hanford. Sulfer water there! But Visalia, there's some tap water. Yumm. Remember when hwy99 was the only to San Jose before I-5 was put in.

I put together a 1350Mah 11.1V pack from a pair that one cell had puffed. Now that plane is hard to hold on to. Got to fly it tomorrow weather alowing.

That SlumCat is really nice. Good work!
Jul 31, 2009, 09:53 PM
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RWCLOUD's Avatar
I taped all of my leading edges with masking tape. Seems harder than bare Depron.

About remembering things...... now what was it that I was gonna say? Don't know if I should say this but what the heck, Remember I'm an old SkyDiver, A friend and I were going to Livermoore one night to jump at a contest the next day, we had a few to many Harvy Wallbangers, decieded to see if we could sneak onto I-5 before it was finished! Well we did, drove 105 mph all the way to 280 ! Yup I remember when 99 went to San Jose.

Water: Kingsburg, Reedly and Sanger have the best water.

Good luck on the maiden

Blue Skies....................R Dub
Aug 03, 2009, 11:51 AM
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Great Maiden

This paper backed foam board is as strong as balsa. Well the maiden flight went really nice. With this "YAK" profile design I drew up from scratch, I left the rear fuse a little weak, thus having to glue in a couple of gussets. It has a funny attribute. When turning into a ~5mph wind, at half throttle, the tail would come down, slowing to just a creep. Well it does have that narrow width (30") and 10" long down the fuse. It never gave a hint of wanting to fall to the left or right. It wants to stunt 3D. No me, just yet. Oversized 10" prop on a 1000Kv "cheap mystery"w/30A ESC/ 1350 3s Lipo.

Real easy to construct this material. Very inexpensive. Easy to repair. The wings took a couple of soft crashes with only scratches and when let go during launch, lifted nicely. See prior posted pics on one way how to airfoil curve this material for a wing, and also J-DUBs leading edge treatment.

Need to clean her up after yesterdays flights then I will post a couple of pics.

Aug 03, 2009, 01:28 PM
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RWCLOUD's Avatar
Congrats on the maiden! When you do a true scratch build and it flies well ,kinda gives you a feeling that the majority of modelers never get to experience and that's sad.

But I have to disagree about Sturdyboard being as strong as Balsa. Take a strip of each material, say 1 inch wide and 12 inches long , support them at the ends and start putting weight in the middle , see which one breaks first.

Where Sturdyboard does shine is its ability to absorb impacts, it justs wrinkles where Balsa shatters. It's a whole lot easier to repair a bad crash with sturdyboard than Balsa and cheaper.

But you really need to experience building and flying with Blu Core ( High Performance Under Layment) Protection Board three or Depron. They are a lot easier to build with, easier to finish , crash better and lighter than Sturdyboard. Plus the wrinkles in these foams can often be steamed out , but sadly that's not the case with Sturdyboard with the paper still on.

Blue Skies................. R Dub
Aug 03, 2009, 01:44 PM
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Well the 5.5x4.5 prop didn't work as well as hoped, ( not enough RPMs) but a 7x5 APC " E" prop works extremely well ! A good solid 60 mph ! 1/2 throttle and let go of her and she's off and climbing about 60 degrees and stable as can be. Throttle up, point the nose up and she's going straight up until shes hard to see! After a few feet of climbing straight up from launch you can start rolling her and the rolls get faster the higher she climbs!

There's are a lot of motors out there that are inexpensive that would power this very well............... Hmmm do I smell a 100 mph set up? Guess there's only one way to find out!....................

Blue Skies................R Dub

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