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nestofdragons

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Jun 8, 2016
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Near Antwerp, Belgium
Jedi, i COMPLETELY follow your idea about using the large landbirds as example for a fun glider/motorized airplane. Not a high performing airplane, but a fun thing. Something that keeps you in the air and let you circle the church tower or let you go back and forth along ridges or just enjoy the local air. As a beginner pilot i ONLY flew like this. I NEVER had any large distance flight. And i was entertained for several years doing that. So ... i really see a market in those fun flyers. But it will be a small one. But that is common in aviation.

I read you want to use a lot of feathers with a really long length. Why? Why not just use a ridig center piece and add wingtipfeathers? I guess it will be less high tech. Those looong feathers seem not to be easy to make.
 

jedi

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2,156
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Sahuarita Arizona, Renton Washington, USA
Jedi, i COMPLETELY follow your idea about using the large landbirds as example for a fun glider/motorized airplane. Not a high performing airplane, but a fun thing. Something that keeps you in the air and let you circle the church tower or let you go back and forth along ridges or just enjoy the local air. As a beginner pilot i ONLY flew like this. I NEVER had any large distance flight. And i was entertained for several years doing that. So ... i really see a market in those fun flyers. But it will be a small one. But that is common in aviation.

I read you want to use a lot of feathers with a really long length. Why? Why not just use a ridig center piece and add wingtipfeathers? I guess it will be less high tech. Those looong feathers seem not to be easy to make.
Good questions.

Why not just use a rigid center piece and add wingtip feathers?

The wing is divided into inboard and outboard sections for aerodynamic and structural reasons. I do not think of the 9 foot feathers as "really long". 12' would be long. 6' is about the shortest flight feather I would make.
The inboard wing section is a really a faring over the folding mechanism. Each of the feathers act as a wing. It is actually more difficult to build smaller feathers.
Each feather is made up of smaller components. The high production replaceable components also applies to each feather. A feather can be preened but also is eventually replaced.
Aerodynamically the inboard wing section and the outboard sections are two separate wings flying in very close formation each with it's own function. What looks to some to be a monoplane is actually a spanwise biplane.
 
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jedi

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Sahuarita Arizona, Renton Washington, USA
Back to the original point. Is there really interest in Vulture type slow thermal soaring with no particular goal except to stay in the air and have a look or is the soaring market really the 90% venture pilot that wants to get somewhere over the horizon and then try to get back home.

Topaz, Billy Floid, VB, Tom Emery, Dana and others speak up.
 
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proppastie

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Feb 19, 2012
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NJ
Back to the original point. Is there really interest in Vulture type slow thermal soaring with no particular goal.
No..... if you look at the Carbon Dragon builds world wide you will have one data point. But that could be because of the complex build and no kits. There probably are more Goat builds, but it's lower performance might inhibit popularity. There also is the Ulf-1. And Swift. Looking at those 4 the market might be saturated.
I do not believe you need short span or feathered tips to have a low speed minimum sink aircraft. ...Again the Carbon Dragon has a long tapered 20% wing. (Aprox. 12 thick 60 cord at root)
 
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BBerson

Light Plane Philosopher
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Dec 16, 2007
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13,564
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Port Townsend WA
I advocate a very low performance motorglider, or more precisely an airplane/glider.
Birds are all motorgliders. A low performance pure glider is not much use in most locations.
 

John.Roo

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Oct 8, 2013
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407
Location
Letohrad / Czech Republic
I advocate a very low performance motorglider, or more precisely an airplane/glider.
Birds are all motorgliders. A low performance pure glider is not much use in most locations.
I agree.... For low performance foot launch glider you need suitable location + specific weather conditions. Self launch low performance motorglider has also limited market, but owner don´t need to live near hills or mountains.
 

rdj

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Sep 10, 2009
Messages
312
Location
Northern California
A fundamental problem with the "birdman" planform is that humans are not birds. We don't have eyes in the sides of our head and we normally sit or stand, which is why humans tend to be more comfortable flying feet-first like in Jedi's avatar. Neither do we have the nervous system needed to artfully control 'feathers' out at the wingtip for stability and optimum thermal performance. Last but not least our weight is why we need high aspect ratio if we want to fly (and fall) slowly. I love the concept, but reality bites.
 

Geraldc

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Nov 12, 2011
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331
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nz
A long time ago they used to draw on the ground instead of using drawings.A bit like the chalk line on the workshop floor.
Alas another lost art.
1592549551429.png
 

Mark Schoening

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Aug 2, 2012
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119
Location
KRHI
I was half-expecting to see this picture:
View attachment 98089
They have great STOL performance, but then what? Cross country flying is like forever going no where. They do teach the builder sheetmetal skills and systems installation, like an apprenticeship for building an RV, except the rivets on this bird are popped, not bucked. So I guess it does have some use...
Perhaps a nod to old age or senility, (or stiff body joints), I built and sold an RV -9, now I'm building a Zenith cruzer…...so much easier, these low, slow, easy to build, and simple airplanes....
 

gtae07

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Dec 13, 2012
Messages
2,001
Location
Savannah, Georgia
I would be interested in a low-performance floater glider, provided it was self-launching, affordable, and trailerable. Part 103 is a plus. I do not have hills or any kind of tow or launch assistance available.

I picture a Goat with a fairing and electric launch based off RC technology.
 

Aesquire

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Jul 28, 2014
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2,428
Location
Rochester, NY, USA
RE: tip feathers.

They are a great idea, but really hard to execute. Ideally you want to individually control them, as a bird does, but even waldoed finger controls don't work well since the human finger can bend, and splay, but not rotate, and you want to splay, rotate, and bend (at the root). That leaves you with computer control. Have fun.

Plus the complexity and weight and fragility make tip feathers a liability that out weighs the benefits for a light aircraft like a glider. Not saying it cannot be done, but I expect it best in a birdlike drone, with a higher power to weight ratio than "real aircraft". ( maybe for nature studies )

re: engines on weight shift aircraft.

The thrust line has to pass through or pretty close to the vertical CG or when you hit low or zero Gs the thrust will pitch the aircraft uncontrollably. An early version of a powered hang glider simply mounted the engine & prop on the Kingpost ( the vertical tube supporting the landing wires ) and the high thrust line could pitch the craft nose down, and you couldn't regain control.
 

Sockmonkey

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Apr 24, 2014
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1,915
Location
Flint, Mi, USA
A fundamental problem with the "birdman" planform is that humans are not birds. We don't have eyes in the sides of our head and we normally sit or stand, which is why humans tend to be more comfortable flying feet-first like in Jedi's avatar. Neither do we have the nervous system needed to artfully control 'feathers' out at the wingtip for stability and optimum thermal performance. Last but not least our weight is why we need high aspect ratio if we want to fly (and fall) slowly. I love the concept, but reality bites.
I once pointed out that small aircraft are essentially tiny cargo planes in that a big % of their fully loaded weight is something that isn't part of the plane.
 

Topaz

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Jul 29, 2005
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Orange County, California
Back to the original point. Is there really interest in Vulture type slow thermal soaring with no particular goal except to stay in the air and have a look or is the soaring market really the 90% venture pilot that wants to get somewhere over the horizon and then try to get back home.

Topaz, Billy Floid, VB, Tom Emery, Dana and others speak up.
Sorry, I just noticed this post.

I'm going to give you two answers, neither of which will be encouraging.

1) Based on what sells, yes, full-up moderate-to-high-performance sailplanes are what people want. Clearly.

2) I personally would love a slow, local, micro-lift soarer for casual after-work or weekend flying. But... Where and how do I fly it? If it's unpowered, I need either a local ridge with easy access that "works" regularly, or I need at least one friend to do an auto or ultralight-aircraft tow to get me in the air. In the LA/OC basin, the former is virtually impossible, to the extent that even the hang-gliding community has all but died out here. The latter requires logistics and a friend/significant-other who's willing to sit on the ground while I have fun. That makes "casual" use a lot harder.

So, what about a motorglider in this category? We don't have suitable small engines in the kind of price range that makes this sort of airplane workable. By the time you've bought a paramotor engine (the most-likely candidate), you might as well buy the 'chute that goes with it and, often, the dealers only sell the motor and 'chute as a package anyway. Convert an industrial V-twin? Heavy, and not really ideal for this sort of application - you might as well step up to a higher-performance airframe around it, which won't cost much more, and do everything the posited micro-lift glider will and be capable of limited cross-country flying under power.

It's not, I think, that there's absolutely little interest in a slow, micro-lift glider. I think instead that the type has an extremely narrow niche use, and would cost virtually the same as something with a lot more capability, uses, and ability to use on a more-regular basis.
 

Aerowerx

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Dec 1, 2011
Messages
5,602
Location
Marion, Ohio
That’s the alien ship from the movie “Cowboys and Indians”.

View attachment 98110
The movie is "Cowboys and Aliens", not "Cowboys and Indians".

Interesting ideas if you watch carefully. Each wing move independently in AoA and dihederal. When coming in for a landing they are arranged to act as a single large area low aspect wing.
 

bmcj

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Apr 10, 2007
Messages
13,495
Location
Fresno, California
The movie is "Cowboys and Aliens", not "Cowboys and Indians".
Thanks. I can’t believe my spellchecker made that change!

By the way, I don’t think we’re allowed to say “Indians” any more, so it probably won’t be long before we have a spellchecker that changes it from “Cowboys and Aliens” to “Cowboys and Native Americans”.

:popcorn:
 

mcrae0104

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Oct 27, 2009
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it probably won’t be long before we have a spellchecker that changes it from “Cowboys and Aliens” to...
Bovine motivational specialists and undocumented personnel.
 
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