CrazyHerb-RCU-delete

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Hi Guys,
Just thought I'd toss this in here...

Amazing! $7.50 worth of foam flies SO good.
On a .47!!!

http://www.rcuniverse.com/showthread...044#post591740

Posted Video to my web site...
http://home.attbi.com/~sherbertson/

Enjoy!!
CrazyHerbb

BMatthews

It's so slow and large it reminds me of the Avro Vulcan doing it's flyby when it was at the Abbotsford airshow when I was a kid.

So simple but so good.

Might just have to follow in yer footsteps.

How about some measurements? Chord and stuff?.... oh never mind. The foam is only 2 feet wide so I imagine that it was aerodynamically engineered and by some amazing coincidence the aerodynamically ideal chord came out to exactly 2 feet..... Do I win a prize?

Just let me crash my PBF and I'll get right onto one of these....

Oh, what about airfoils? How much did you shave off there on the leading and trailing edges? I know it's not critical but you obviously sliced off a wedge with a kitchen knife or something.

PS: Oops, looking at the pics on your web site I saw a joint. So what IS the root chord. And it's not that big a deal but you might as well toss in the tip chord too.

CrazyHerb-RCU-delete

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Hint...those are full-length yardsticks in the pics...
I'm guessing around 40 inches..maybe 42...

Ya know...hadn't thought about it...but it does kinda have a lumbering...menacing "Vulcan" look to it....not intentional...but cool, none-the-less..

Tips are 10 inches NOT including 3 inch elevons. Made from 3/8x4x48 sheets.

I hot-wired the taper paralell to the chord (from root to tip) symetrically at the rear about 6 inches from trailing edge, left it about 1/2 inch thick. The leading edge is flat-bottom style with just a hint of lower at the tips to get a little washout effect. I did round the bottom leading edge just a tad...like 1/4 inch...but for the most part its a FLAT wing...

If you look at the first post (scroll up on the RCU link above I have a pic of what I did withthe foam... cut the sweep and added the cut material to the front... you can build TWO of these from a 4ftx8ft sheet of 2 in foam if you do it right....was 12.99 at Home Depot. So, about 7 worth of foam...

I'll see if I can take a couple pics of the tip and post here...

Good Luck!
CrazyHerb

3dmagic

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where is the center of gravity, i gotta build one

TomJacoby

Excellent!

Very similar to the "Moonlighter" kit that was available back in the '80s - made from blue construction foam, IIRC.

Here's the one I built.

TomJacoby

More on the Moonlighter:

Fox .35; sliding tray mixer; half-round balsa LE; trike gear.

Needed a bunch of reflex (up elevator) and flew nose-up. Fairly gentle, moderately fast, poor glide.

CrazyHerb-RCU-delete

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The Center of Gravity is around 22 inches from the TRAILING edge (not rear of the elevons). It's a conservitive, slightly nose heavy CG but still working great. About 20% MAC.

The glide on this thing is INSANE....real floater. I had a dead-stick at about 500 ft and it took two minutes to glide back to my feet.

One thing to mention about Delta's. They are VERY efficent in straight and level flight. However, as soon as you bank or climb hard they loose it.

There is NO spar in the Giant Delta...but I did run a single 3 inch wide length of fiber strapping tape from tip to tip...where the sweep meets the tip. The wing is strong enough, but if I were to do it again...(and I will)..I'd run a 3/8 inch square hardwood spar just for added security.

I did try a flat spin with the HUGE rudder, but due to my nose heavy condition it will just do a big super-flat circle. That tip just WON'T stall! Also, need to increase my throw on the rudder a bit..I think it's only about 20 degrees...didn't want the plane to freak out on the first flight.

Let me know if anyone is going to build one...I'll try to answer any questions.

Good Luck!
CrazyHerb

3dmagic

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i am going to build one soon do you have any close up pics of the wing thanks for the help

CrazyHerb-RCU-delete

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3D!

I'm away from home this week. But when I get back I'll get a little web page built on the construction and some close-ups.

Post here if you have any really big questions...We'll share with all!!

Can't wait to get a fleet of these big ol' things flying....

INVASION of the Giant wings!!

CrazyHerb

VoughtF4U

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Crazy Herb,

I started mine last night. I have been looking for simple foam designs to build. I have to keep up my reputation at the field for bringing crazy but cheap airplane designs to the spring funfly. I am using half the 4x8 sheet for this delta and the other half will be used for a 4x4 semi-scale Vought V-173. It is basically a big flying pancake with two big props.

The foam I bought at Home Depot was 2 inch thick, but it was pink and cost about $22 a sheet. Not as cheap as your but it will still work. I also noticed on my foam sheet, it was pre-scored so that you could break it into strips. The scores run spanwise on mine so they really shouldn't be a problem. I will be using a zig zag pattern of fiberglass reinforced tape similar to that used on a Zagi flying wing. I plan on using an old Saito .65 four stroke that looks like it is on its last legs.

For the V-173, I plan on breaking the foam into strips at the score marks, gluing it all back together with luan ribs inbetween the strips, sanding it all down to shape and then fiberglassing the whole thing, latex paint for color. It will be a little heavier, but not much.

Thanks for the idea...

Ralph V

Crazy Herb

Your big delta looks great. But looking at the drawings you
show it as 96". 48" to the center, did you cut 5" off of each
tip to make it 86" wing span? Also on the drawing the wing
tips come out to 6".
What size servos did you use? And what size engine did you
use, and do you have any landing gear on it?
I like it, and want to build one next week end.

Thanks
Ralph V

CrazyHerb-RCU-delete

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Oh Ya! Ralph, good catch... YES I clipped 5 inches from each tip and the tip chord is about 10 inches. The drawing was done before I acutally built it....

I used HS-700 1/4 scale servos (rudder, 2 elevons, 1 standard for throttle)but you could use standard high torque I imagine...maybe even standards.

The airframe is only 6 lbs even with the big servos. So not alot of mass to have to move...but the surfaces are BIG so I wanted to make sure....and they were just sitting in my servo drawer.

No landing gear....I'm going to mount a lite ply plate on the bottom and play with that though....just wanted to get it to fly first...didn't know it was going to fly so well!!! Now I can explore options....

Maybe even a beefed up version with a chainsaw conversion....42 cc or whatever I stumble on!

Thanks for the catch!!
CrazyHerb

Plans can be found here:
http://home.attbi.com/~sherbertson/

Gordo-ProBro

Hey CrazyHerb, I'm thinking of building a wing like your's, thanks for the info. I used 4x8 sheets of 1" foam for the XXXXXLarge PBF. The wing you built could be cut in one peice if the foam quality is similar. Do you know if there is a difference in the 2x4 type?

Thanks
Gordon

Ralph V

Crazy herb

Thought you might like to see a picture of the Big Delta
that My sweet heart and I built a couple of years ago.
Its about 9 feet in length, 82" span, and weighs 26 lbs.
Power is by a 30cc Glow engine.

Ralph V

Wayne H

Herb,
Please do put together some type of webpage detailing the construction. I WANT ONE OF THESE!! Did you use an electric foam cutter on this project or did you cut the leading and trailing edges by hand with a saw or what? I seriously think you started a new movement here. I've got three guys at the club wanting to build one so far and I am sure many more will follow after seeing ours fly. Is the Blue, Pink, or White foam better than the other or will they all work equally. I think the Pink is more denser but maybe someone else could chime in on this. Can't waite to get mine flying. I will power with a Tower .75.


Ralph V-
More info on that beautiful plane please. I have a Homelite 25cc that I would love to put in something like that. Very neat looking. What is it made from. Plans? More photos?

CrazyHerb-RCU-delete

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Wayne,
YES I did use a hot-wire cutter, a small 20 inch. I cut from the root to the tip using 48 inch hardwood rails pinned to the foam. One along the top of the wing and one on the leading edge.... I dropped the leading edge about 1/2 inch out to the tip so it gives a gradual "washout" effect. The trailing edge is just 5 inch symetrical all the way across the wing (easy two cuts).

The 2 inch white foam (both 4x8 and 2x4 sheets) are much lighter than the pink foam. And actually seem to ABSORB impact better (seems a little more spongie). The Pink foam is MUCH more rigid though....but doesn't like hard bumps quite as well without chipping/cracking...."choose your poison". I just went with CHEAP, light, and big! I would think Pink foam would work just as well in any case.

I haven't had a lot of time to be able to get much more details then what I've posted here. New baby, work, in-laws....etc....
I will Post more to the web page as I get it....

Wayne....your not far from me! Might be worth the drive to get a whole Giant Delta Fly-in going here in the spring time...hehehe...An INVASION of Cheap Giant Deltas!! Cool...

Just want to say thanks for everyone's interest, and sorry for any delays in getting info to ya'll. Life gets busy for this guy sometimes....trust me...I'm dying to get this thing back out at the field (200 yards away) and get some more video and pics and get the web page sorted out....

Just post here or e-mail me if you have questions.... I'll try to get the plans "fixed" tomorrow....pending schedule.....

High Flights All!!
CrazyHerb
http://home.attbi.com/~sherbertson/

Gordo-ProBro

Thanks herb. We all know it's a lot of work being a dad and RCer at the same time. I have 7 year old triplets who go to the feild with me every time, and soon will be my flying buddies. I can't tell you how many toys have been delivered to me for repair while I was building on my shop! But it's the best part of life!

I think I'll try the pink stuff, and let you know how it goes. My XXXXXlarge PBF flexed a lot at first, but it's doing better with a stiffener each way. Thanks for the clarifications on construction. The site is fine, plenty of info for the simplicity of the project. If you look at Dave McD's site on the PBF, it's about NASA quality, I wish I had the time he puts into his site!

Later
Gordon

VoughtF4U

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I am using the pink foam for mine. It was the only 2" thick foam that the home improvement stores in my area stock. I built a wire cutter to try and cut this foam and it worked great for the first cut. I need to work on my power supply though because it got too hot and I couldn't control the temperature very well.

After that I just cut the rest with a hacksaw blade. It worked well for a rouch shape and then I hit it with my wife's mouse sander. I used anything from 80-150 grit paper and it all sanded very quickly and easy. Shaped it all out in about an hour with the cutting and sanding. The hot wire cutting was easier, but the hacksaw blade worked well too.

The pink stuff does dent pretty easily, I dented the leading edges just moving it around my garage. I need a bigger workshop evidently.

I used a dremel tool with a drill bit to route out a slot about two inches behind where the front and the back pieces of fowm glue together. I glued a yardstick into this slot for a spar. I also glued on my other yardsticks for the backbone down the center.

I will be adding my zig-zag tape pattern for strength this week and should have everything installed by the end of this weekend. I am thinking about adding a piece of hardwood along the leading edge just to keep it from denting much more.

CrazyHerb-RCU-delete

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The best wire I have found for cutting foam with my 22 inch bow is the Sevalon Steel fising leader wire...it's a stranded (not solid) and has a thin plastic coating you have to burn off. I just scraped it so my aligator clips could heat up the wire to burn it off. Can't remember the gauge keep thinking .018 or .024 or something. I use both sizes...the .018 gets hotter for short cuts...the .024 is better for longer bows with more amps...at least 10.
FOUND IT!!
http://www.insidesportfishing.com/ma...sp?CLID=M182F3

$2.49 for 30 feet!!!

They sell little 1/4 inch long crimp tubes too...but I can't seem to find those...

I've cut probably 300 ft of foam with this ONE piece of wire (connected to a 6amp automotive battery charger). And I have it pulled pretty tight!!

Vought - You may want to add a balsa leading edge...OR Here's something I've done in the past that helps a little...Wrap some ELMERS glue soaked (or epoxy) 6 inch strip of brown Kraft paper over the leading edge. When it dries it will be nice and stiff. I will probably do something like that on my next one. I like your spar idea...are you placeing the yardsticks vertical in the foam or flat. I would think vertical would be awesome shear strength.
If you get pics let us know sounds like your project is a winner!

Gordon - Saw your thread here on RCU on the XXXL PBF...NEAT! I'm still waiting for the first GASSER powered one..like full 6ftx6ft HUGE!@!..The PBF would be perfect for a chainsaw conversion (Beam mount style) and the extra weight in the nose would be a benifit to the short CG location on the PBF's. I have a pic of my 2 inch foam 48 inch PFB here... http://home.attbi.com/~goldcountryae...ntpizzabox.jpg

Here's a shot from the nose...

CrazyHerb

CrazyHerb-RCU-delete

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Here's a shot of the "business end".

Bruno Stachel

My Feedback: (4)

CrazyHerb, Great design. I'm taking notes. Can't wait to see the wife's eyes when I come home with a sheet of that foam!

The engine in your last pic appears to have a muffler extension going through the foam, I assume to the bottom of the wing. Did you use an aftermarket extension or did you fabricate something on your own? Any problems with heat against the foam?

CrazyHerb-RCU-delete

My Feedback: (2)

AH Ya! I was going to mention that...

It's a model rocket tube.... not attached to the motor...just set in at an angle with 1/8 inch from the exhaust exit....I slapped a bunch of 12 min epoxy all around....it works GREAT and I have very little leakage on the top of the wing....it keeps all the radio gear dry and save cleanup....

I'll see if I can get a close-up of it....took like 5 min to do...and saves MUCH clean-up...

You could do this with a toilet paper roll tube too...just cut it and wind it up tighter like 1/2 inch diameter and poke it through!

CrazyHerb

JIMESTES

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I finished mine this weekend and other than destroying an engine on maiden flight it flys great.
I have some other threads started about the over speed in a dive problem I am having.
I think I have it resolved now.
I noticed you used 1/4 scale servo's I didn't/
and was not able to pull out of a high speed dive.
But I changed the elevon servo's and the engine and got two more perfect flights out of it.
I plan on putting counter tabs (what ever you call them) on the outboard ends of the elevons.
mine is 88 x 36 and fueled it weighs 5.25. I put landing gear on mine I need it to help give some forward weight.
with the os 46 and apc 11x4 it has unreal vertical climb and prop hanging is a breeze.
I put my first three flights on in about 15-20 mph winds.
Take off roll is about 5 feet.
I plan on trying a vertical take off this weekend. With the way I built mine it sits straight up and down on the rudder and elevons.

I will let you know how it goes

I just wanted to thank you for the idea.

Later Jim

Gordo-ProBro

Hey herb,

Looks like you really started something here. I'm a bit slower to start this one, 'cause I have sooooo many projects, but if I keep thinking about it I'll probably do it this weekend. I'm still trying to finish up my World Models Mustang, and I have my newest Somethin' Extra ARF still boxed up. Since my wife bought both of these for me I figure I better make them my prioity! Plus more mods to the XXXXL PBF, and building annoth regular PBF, I actually wore one out, and its motor too! Thanks for the details on the cutter, I've always thought this was lots more difficult to cut foam, I'll have it working this weekend for sure!

Gordon

JIMESTES

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Here is pic's