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Old Feb 13, 2014, 12:59 PM
Which way is it blowing?
SF Sloper's Avatar
San Francisco, CA
Joined Feb 2009
350 Posts
Question
Biplane Slope Wing?

I have a combat wing already and thought since I have two combat wings that my brother gave me, it might be fun to experiment.
Has anyone done this or seen it done?

I figure vertical carbon rods and coroplast end plates.
Full elevons on both wings linked with vert. rods.
It may only need one set elevons, but start with two to begin?

Alignment and balancing might be tricky.
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Old Feb 13, 2014, 01:24 PM
Confirmed Chronic
screamin' eagle's Avatar
Pacific Palisades, CA
Joined Jul 2004
9,208 Posts
Looks cool. I'd try it.

The topic of slope biplanes comes up every now and again and the conventional wisdom seems to be that they are too draggy to be much fun, but you shouldn't let that stop you. I'd keep all the radio gear in the bottom wing to keep the top wing light.
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Old Feb 13, 2014, 02:04 PM
SlingWinger
San Bernardino, California, United States
Joined Oct 2004
1,629 Posts
Check out the "Easy Riser" and "Icarus" biplane hang gliders.

This is a project I've thought of trying myself, but instead of using two combat wings, My idea is to build a large, superlight floater glider for when the conditions get too light for most gliders.

While the biplane configuration is aerodynamically "dirty", it has the potential of providing the strongest-for-the weight structure.

This is why most of the early aeroplanes were biplanes. The engines they had were heavy and didn't have a lot of power, so to keep the power loading and wing loading down they had to have the lightest possible structure.

Octave Chanute, an early pioneer that worked alongside the Wright's, was an engineer and saw the advantage of using the truss "bridge" structure as a way to get maximum wing area for minimum frame weight.

So I was thinking of using sheet foam, "skeletonized" ( lots of lightening holes) like the indoor guys do, and using the biplane structure to avoid having to use carbon tubes or whatever for stiffness. I think FFF fan fold foam or Dollar Tree foam would work well, using skinny (split) bamboo skewers as the uprights.

To reduce the inefficiency of the biplane configuration (the high pressure under the top wing interferes with the low pressure on the top of the lower wing), use at least one chord-length distance between the wing.

Many latter-day biplanes also realized a boost in efficiency by using "negative stagger", i.e. the upper wing's leading edge is staggered back to be roughly even with the trailing edge of the lower wing. Witness the Beech Staggerwing and the more recent homebuilt HiperBipe.

If using negative stagger, I would set it up so that an "up-elevator" command would raise the elevons on the upper, more rearward, wing and the elevons would go down on the lower, more fwd wing. This should improve efficiency, but it would have to be tried to see if it worked.

Anyway, Go For It! Let us know how it all came out.

Yours in Flight, Steve
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Old Feb 13, 2014, 02:31 PM
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Joined Jan 2003
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I always wanted to do a Curtiss Sparrowhawk without the landing gear.
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Old Feb 13, 2014, 09:26 PM
Which way is it blowing?
SF Sloper's Avatar
San Francisco, CA
Joined Feb 2009
350 Posts
Thanks to all for the feedback.

Interesting stuff on the staggering of the wings, though historically it looks as if positive stagger was the way to go on the old bipes.
Looking at the Icarus biplane/hang glider, it looks to have neutral stagger or none, which is the way I'll probably start the build and move some ballast around to find the CG. If that doesn't work, I may have to experiment with stagger.

Right now I'm building a fireboat on the Scale Boats forum (build blog here), but I'll try to make some time for the wing(s) as well.
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Old Feb 13, 2014, 11:21 PM
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chip.greely's Avatar
Carlsbad, Ca
Joined Mar 2007
2,964 Posts
Hmmm,

I picked up Dale's Beechcraft Staggerwing and am holding onto it for him,...... but I'm somewhat doubtful the staggerwing would transpose to a Combat Wing.

I might suggest you try three EPP uprights/verticals with CF rod reinforcement and cover in 1.7 or 3mil laminating film, since exposed rods/wires have more drag than tapered surfaces
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Old Feb 14, 2014, 04:42 AM
I don't like your altitude
Stupot46's Avatar
Joined Sep 2011
3,153 Posts
Burgess Dunne,one of the first powered flying wings
http://www.fiddlersgreen.net/models/...lyingWing.html
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Old Feb 14, 2014, 04:10 PM
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United States, OR, Tualatin
Joined Apr 2005
2,421 Posts
The Wright Brothers made it work for them. They did their version of hang gliding with twist wings for turning, because that is what birds do to turn. According to the information at the Kiddy Hawk museum, they made over 200 test glides off the sand dunes to perfect there hang gliders before trying a motorized version.
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Old Feb 15, 2014, 09:04 PM
Which way is it blowing?
SF Sloper's Avatar
San Francisco, CA
Joined Feb 2009
350 Posts
If it does work, it would be a hoot to velcro a pilot on-board!
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Old Feb 26, 2014, 11:47 PM
Keep calm and don't blink
KiwiKid's Avatar
Hamilton, New Zealand
Joined Jun 2005
1,960 Posts
Here's a few interesting concepts - I kinda like the V3: http://minifly.rchomepage.com/plans.htm
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Old Feb 27, 2014, 10:05 AM
Which way is it blowing?
SF Sloper's Avatar
San Francisco, CA
Joined Feb 2009
350 Posts
Quote:
Originally Posted by KiwiKid View Post
Here's a few interesting concepts - I kinda like the V3: http://minifly.rchomepage.com/plans.htm
Cool stuff. Thanks.
I've made absolutely no progress on this, but did go to the rained-out Daytona 500

We watched the conclusion on TV later that night
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Old Mar 05, 2014, 11:14 PM
.....till the wind drops.
Sean Oelofse's Avatar
Port Elizabeth, South Africa
Joined Oct 2006
3,504 Posts
"Ultimate" slope Biplane.

I built this one from a shock flier plan.......just gave it a wing profile (basic Clark Y) and the fuzz some "body" ........drag?......didnt notice any more than a normal slopie!

Ultimate Sloping at Maitlands (2 min 19 sec)
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Old Mar 06, 2014, 12:53 AM
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6,910 Posts
That things surprisingly fast. Are we about to start seeing a bunch of PSS EPP Ultimate Bipes?
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Old Mar 06, 2014, 07:52 AM
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screamin' eagle's Avatar
Pacific Palisades, CA
Joined Jul 2004
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Myth, busted!
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Old Mar 06, 2014, 12:03 PM
3D Toy Designer
MicroRotors's Avatar
USA, CA, Hesperia
Joined May 2001
4,451 Posts
Looks like I better jump back on the Grumman Duck!
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