The 'daydreamers' thread...post your craziest designs and concepts here

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pictsidhe

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Craziest daydream? That'll be the dragon ornithopter, with saddle. Hell, two saddles!
There are a couple of design details that I am still a tiny bit fuzzy on. ;)

A lttle easier would be my atlantic flyer. 60' span flying wing motorglider. Twin 1l turbodiesels. Cruise altitude 52k with a pure O2 atmosphere. Pressurised is too much weight. Flutter avoidance is a major design hurdle.

And you guys think my plastic 103 is crazy. It's just a warm up!
 

pictsidhe

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Rotor torque is low due to low power and can be corrected with rudder even at a standstill if the pusher prop is running. You can see autogyros using jump takeoffs have no torque problem.

One important thing that a constantly powered rotor does is that it allows the use of wings for cruise while maintaining safe rotor RPM in flat pitch to prevent rotor instability.
Jump takeoff gyros only power the rotor on the ground, where the ground will resist the torque. The last thing done before jumping, is to disconnect the rotor power. Tip jets are the torque free way to power a rotor, but have their only quirks.
 

bmcj

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How about a Magnus wing? Just an overgrown popsicle stick that spins in place of an ordinary wing.
 

choppergirl

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My totally bizarre daydream would not be a specific airplane, but an airplane store.

Even more bizarre, a store for hang gliders. Where you could walk in off the street, and browse hang gliders, try one on, kick some non-existant tires, shop accessories... picture it much like a motorcycle store or used car lot.

As far as I know, no such thing, a store dedicated to hang gliders only, exists anywhere on the entire planet.
It's right up there in rarity with a zoo filled with nothing but unicorns only...
 
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FritzW

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As far as I know, no such thing, a store dedicated to hang gliders only, exists anywhere on the entire planet.
Waaay back in the day (70's), during the peak of the hang glider craze, we had a hang glider store in Albuquerque. Hang gliders and hot air balloons have always been a big deal in Albuquerque.
 

bmcj

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Here’s one that often crosses my mind...

Make a wing with an airfoil that has a standard airfoil (flat bottom or semi-symmetrical) nested in an undercamber airfoil. Together, they look and act as a single normal airfoil, but can be separated by a significant distance by a scissor arm or swing arm, creating a biplane that has a normal airfoil lower wing and a high lift undercamber airfoil upper wing. It could enhance the cruise to stall range significantly.
 

billyvray

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Similarly, a multi-slat wing (arranged for a larger spread and undercamber) that collapses to a much narrower higher aspect wing. Not sure if worth the weight...
 

Starjumper7

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Jump takeoff gyros only power the rotor on the ground, where the ground will resist the torque. The last thing done before jumping, is to disconnect the rotor power. Tip jets are the torque free way to power a rotor, but have their only quirks.
Yes, I'm aware of that. I think I saw an article somewhere about the benefits of a constantly powered rotor (with a small amount of power). Basically enough to keep the rotor turning when most of the lift is coming from the wings. I can't recall if it was theoretical or if someone has tried it.

Of course with the mechanical powered systems there are too many things to break, but if you power it with a small electric motor there will be almost no reliability problems.

The important point is that, with this concept, you only want a small amount of power to the rotor, just enough to keep it spinning safely while in flat pitch during cruise. I realize that due to gearing there would be a lot of torque multiplication, if there was any problem it would occur during the jump takeoff when there is slow forward speed, but still, I think slipstream over the rudder will correct for it. The power to the rotor could be turned off for the few seconds of the jump.

When gliding downwards we would be wanting to turn the power to the rotor off, I think, and get it set up in autorotate mode.

Another idea I had for this, which I mentioned in the first post, is to use engine/generator with electric motors. The purpose of that is to locate the propeller(s) in more ideal locations. There are many ways to arrange electric motors on an aircraft, of course. One way I envision is to have a long tail arm, like on a sailplane, and put the prop on the tail. This allows for a bigger diameter and much more efficient prop, which could make up for the extra weight of the generator. Actually my drawings are of an aircraft that looks a lot like a sailplane, but with a lift rotor on top, and a pusher prop on the vertical tail.

Another thing I have found is that electric allows for a lot of small props, and if you do the math you find that you can get a lot of disk area with several small props, which could be arranged on the main wing. I'm assuming that ten 10HP electric motors would weigh about the same as one 100HP electric motor.
 
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Starjumper7

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Craziest daydream? That'll be the dragon ornithopter, with saddle. Hell, two saddles!
There are a couple of design details that I am still a tiny bit fuzzy on.
Did you read Space Odyssey 3000? It has one of those in it. Speaking of dragons, I recently published a book that refers to them somewhat.

Flutter avoidance is a major design hurdle.
Not for me it isn't, just put some weights in the leading edges of the wings and control surfaces, that's the only 100% sure cure, and it's easy.
 
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Riggerrob

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Here’s one that often crosses my mind...

Make a wing with an airfoil that has a standard airfoil (flat bottom or semi-symmetrical) nested in an undercamber airfoil. Together, they look and act as a single normal airfoil, but can be separated by a significant distance by a scissor arm or swing arm, creating a biplane that has a normal airfoil lower wing and a high lift undercamber airfoil upper wing. It could enhance the cruise to stall range significantly.
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Are you trying to say that you want an X-wing fighter from the Star Wars film franchise?
The first Star Wars film motivated me to complete my private pilot licence.

During the 1930s, a Russian engineer built a few foldable biplane prototypes, but when they offered no significant performance advantage over monoplane fighters, they disappeared. Nivichin-Shevchenko IS-1. The IS-1 had a complex pneumatic mechanism that retracted wheels into the lower wing, then the lower wing folded upwards at mid-span. the inner, lower wing retracted to lay veritically in fuselage sides, while the lower, outer wing panels retracted into the concave underside of the top wing. On the ground, the IS-1 resembled a contemporary Polikarpov biplane fighter, but in the air, it looked more like a gull-winged Polish PZL monoplane fighter.

Greg Catto - of propeller fame - took up the X-wing challenge during the 1970s and built a fixed X-Wing, canard, prototype using Burt Rutan's innovative foam and fibreglass construction methods. Catto copied the retractable nosewheel configuration from Rutan's Long Eze and wingtip main wheels from Rutan's Quickie. The Acro-X also had wingtip mounted rudders and vertical stabilizers.
Catto's Acro-X prototype flew well until its bubble canopy came loose in flight, jammed into "X" bracing wires and forced him to bail out. Look up the "composite pusher biplane canard thread" on www.homebuiltairplanes.com.

When I grow up, I still want an X-Wing fighter!
 
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bmcj

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Are you trying to say that you want an X-wing fighter from the Star Wars film franchise?
The first Star Wars film motivated me to complete my private pilot licence.

During the 1930s, a Russian engineer built a few foldable biplane prototypes, but when they offered no significant performance advantage over Polikarpov biplanes, they disappeared.

Greg Catto - of propeller fame - took up the X-wing challenge during the 1970s and built a fixed X-Wing, canard, prototype using Burt Rutan's innovative foam and fibreglass construction methods. Catto copied the retractable nosewheel configuration from Rutan's Long Eze and wingtip main wheels from Rutan's Quickie.
Catto's prototype flew well until its bubble canopy came loose in flight, jammed into bracing wires and forced him to bail out. Look up the "composite pusher biplane canard thread" on www.homebuiltairplanes.com.

When I grow up, I still want an X-Wing fighter!
No, I suppose x-wing would be one way to do it, but I wasn’t thinking x-wing. I was thinking more like a wing (shell) that deploys straight up and parallel above the wing like a biplane. You could even deploy the shell outward to simulate more span or aspect ratio, but that would be ever. more of a structural nightmare.

I suppose you might even be able to do the same idea with a soft parafoil that sucks down tight to the top of the wing and then deploys by letting spanwise risers extend (deploy) from their (the risers) retracted position in the wing.
 

Riggerrob

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No, I suppose x-wing would be one way to do it, but I wasn’t thinking x-wing. I was thinking more like a wing (shell) that deploys straight up and parallel above the wing like a biplane. You could even deploy the shell outward to simulate more span or aspect ratio, but that would be ever. more of a structural nightmare.

I suppose you might even be able to do the same idea with a soft parafoil that sucks down tight to the top of the wing and then deploys by letting spanwise risers extend (deploy) from their (the risers) retracted position in the wing.
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X-wing is the simplest way to build a retractable biplane, but it does require a deep fuselage to gain sufficient separation between the upper and lower wings. You also need an automatic flap to fill the massive gap in the fuselage side.

Another way is to build a high-wing, cabin monoplane with an extra wing laying on top of the "cruise" wing. When approaching a short airstrip, you hydraulically extend the upper wing 2 or 3 chords above the fuselage to double wing area. ???????????
 

Riggerrob

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I would also love to see a serious attempt at an asymmetrical aircraft, something simple along the lines of a Moni motorglider with a full glider canopy (no engine there) and the engine moved out to the wing. It would have great visibility and attract attention at every airport.
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Speaking of assymetric airplanes ..... when I grow up, I want a half-scale replica of a Blohm und Voss 141. A single-seater version would be easy with 80 to 100 horsepower. A two-seater version would be a bit more challenging. My first sketches started with the wing from a Jodel/Falconair F-12.

On a more practical note, for the ISO 20 shipping container challenge, I sketched an assymetric ultra-light with a single-seat pod hanging below the wing and tricycle undercarriage. Both the engine and tail boom are offset to the left. The tail boom folds sideways - to lay along the right trailing edge - for stowage in the shipping container. I also contemplated folding one outer wing to increase span/improve span-loading.
 

Riggerrob

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Moldless composite de Havilland Comet (the racer, not the airliner)....

Or, if you'd prefer to carry a couple more people, same concept but a full scale Mosquito with a pair of PT-6s or similar. Basically taking the idea of the Grand 51 to the next level. .......
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Recently a group of Frenchmen built and flew a wooden, half-scale replica of a DH Mosquito ..... guessing at exact scale. They enlarged the canopy a bit to hold two crew. They installed horizontally-opposed engines and concealed the cylinder heads in bulges similar to those installed on Mosquito night-fighters.
 
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