Flying wing as cheap and simple option for basic fun flying.

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Topaz

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Part of this wandering of emphasis is the usual disparity in what people want in a project, and part of it is the fact that there's "flying wing" in the title. The latter almost ensures that discussion will venture into the BSLD territory, even though BSLD isn't limited to, or particularly more beneficial for, flying wings. It's just become tightly associated with flying wings because of the Horten's interest in using it to generate proverse yaw so that they could eliminate all vertical surfaces.

BSLD does provide a theoretical reduction in induced drag and that could be used to offset the induced drag penalty inherent in tailless designs, but there are much simpler ways of doing that than BSLD and the complex twist and geometry it will impose on the wing build.

It's all well and good to want to advance the state of the art, but the OP's intent in that area was to advance construction cost and simplicity, not aerodynamic improvements. That ought to be a sufficient advance unto itself, IMHO, and bringing in cutting-edge aerodynamics doesn't necessarily contribute to meeting that goal.

Maybe there's a sweet little confluence of some novel aerodynamic trick and the desire to create a radically simple and quick-build airframe, but that'll be a long stretch and a lucky shot.

My opinion, for what it's worth. YMMV.
 

Aesquire

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Maybe there's a sweet little confluence of some novel aerodynamic trick and the desire to create a radically simple and quick-build airframe, but that'll be a long stretch and a lucky shot.
I don't know about novel, as pretty much every combination has been tried, if not flown, but simple & quick build seem within reach.

And often other goals push otherwise neat ideas out of the nest, like "Has to fit in a standard container" and "The most time & effort I will bother to put into assembling a folded airplane is 3.42 minutes." ( if you think I'm picking on you, you are wrong, I'm mocking that Other Guy. :) )

Very Rough Design Proposal, call it the Pod Thing 1... or PT1 for short. ( And I'm open to a name change )

PT1 would have a pilot & engine pod that hangs below the wing. ( lots of window, please ) It includes a wing center section to plug the wing panels into, automatic hookup of controls. ( Sailplane style ) For drag purposes, the Wing Center section is mounted on a streamlined pylon about 2-3 feet high. This allows for wing tip clearance during flare to takeoff & land. Wing is a mildly tapered mildly swept wing with washout, outboard elevons, ( "regular" or Junkers, your choice ) and Removable tip fin/rudders, that deflect outwards, only, singly, or together for drag braking.

You can also figure the numbers for a plank, and a forward swept wing, but that wouldn't have tip rudders, instead a removable single fin/rudder on the top, rear, of the pod.

None of the above is original, the configuration has been suggested repeatedly... :)

The advantage of the PT1 is it breaks down fairly easily, and the wing structure is quite simple. The disadvantages include the weight of the pylon structure, and arranging engine, fuel, etc. to put the pilot's seat right on the CG. ( or both seats in a 2 seat side by side. )
 

Fred C

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Many of us could make the very same complaint from the opposite direction - when we wish to make a modest but realistic improvement on the status quo, so many people immediately push the discussion out to the border of fantasy, taking the position that any useful improvement must completely abandon everything that has been the "status quo".

So it also gets difficult here to discuss a slight alteration to the status quo, because the science fiction futurists and the "clean sheet is the only sheet" proponents reduce any modest discussions to rubble.

How woud you suggest a fair and useful discussion thread for "cheap and simple flying wings" that is not prejudiced against modest improvements to existing Backstrom and Fauvel designs... and that is also not prejudiced against the Tripstix inflatable surfboard discussed in your post... and that is also not prejudiced against a vacuum molded and resin-infused carbon Prandtl-Bowers-Horten wing?

The only answer that I can offer/suggest is to keep status quo and clean-sheet in separate dedicated areas so silly people like myself cannot spoil a game-changing exotic approach.
Such a great retort.
 

rotax618

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How about something simple like this.
 

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Sockmonkey

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There is this guy. Wouldn't be hard to make it so the wing rotates 90 degrees on top of the fuselage to make it more compact for transport. Might wanna add detachable struts though.
s8k0vWi.png
 

rotax618

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Note there is no rudder or yaw control only fixed endplates, I spoke to the designer/builder, and he said it did perfectly coordinated turns - the nosewheel was spring centered castering with cable bias steering (if you can understand) for X-wind landings.
4DA29B03-0F36-4AA4-9123-C904658AC97E.jpeg 36E2A894-060B-4B39-B1A4-0601788ADECD.jpeg
 

J.L. Frusha

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Disregard all previous comments about twist. When you said it would be similar to the AV-44 I assumed you meant a low AR tapered plank with little or no sweep of the 1/4 chord. This drawing shows substantial forward sweep. BSLD hasn't been tried with forward sweep because it probably won't work.
Actually, it hasn't been tried... PERIOD. Even NASA hasn't tried it. How do I know? I asked.
 

Victor Bravo

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There is this guy. Wouldn't be hard to make it so the wing rotates 90 degrees on top of the fuselage to make it more compact for transport. Might wanna add detachable struts though.
Noooo, IMHO there is no real need for struts on a concept like that - with such a short span, and a (likely) very thick wing for this mission. Your original rendering is pretty close as-is, it may only need a tiny little more vertical area behind the CG to deliver sufficient yaw damping.

But otherwise it seems very much worthy of pursuing, which I think I may have said previously about this concept. The only significant 'drawback' that I can see is that you'll need a full tricycle gear setup, something along the lines of the Aerosport Quail. And this is not actually a drawback, it's a necessary evil that just happens to take a little aesthetics away from an otherwise very clean, sleek shape.

So building it as a cantilever wing that rotates on the fuselage, like the "Backyard Flyer" ultralight, would deliver a real-world advantage in storage and transport, setup time, etc.
 

addaon

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I don't know if BSLDs have been investigated in detail for forward swept wings... but again, I encourage anyone curious about this to play with AVL. For this sort of question -- estimating Oswald efficiency, proverse/adverse yaw, and control authority with varying CG -- VLMs are very suitable for even in-depth investigation. You won't get useful absolute drag data, and you won't get any info about nonlinearities at high AoA -- but answering "how does this lift distribution fly with this planform" is the work of a few minutes.
 

addaon

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Yeah, AVL is one of the more accessible VLM codes out there. It’s downside compared to others is that it’s 2D rather than 2.5D — it works with the mean camber line of the wing rather than the surfaces (fancier VLM codes) or the volume around it (“real” CFD().

There’s no UI for entering data, but the data format is really straightforward — it’s easy to write by hand, lightly script a spreadsheet to generate it, slap together a UI, or just generate from any existing scripts that you use for analysis. There is a graphical output that’s a bit old-school but quite useful.

If folks are actually interested, I’m glad to work an example (in a new thread, or live). Even a plank is interesting, but we can do something fancier if people want.
 

nerobro

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How about something simple like this.
A thing that misses a lot of people.. like us.. is it needs to be pretty.

The target audience shops mostly with their eyes. If it doesn't look neat/awesome/worthy of effort they're not gonna build the design.

It's worth noting, that flying wings often have a fairly narrow performance envelope. And some have even worse recovery performance.

A project like this is gonna need to tick ~almost all the boxes~. Be easy to build, fast and small build steps, difficult to build dangerously, perform well, and look good. I think this is totally do-able.

Easy to build: Not fiberglass on foam. That's messy and takes lots of room. And you're stuck between steps with curing. And stuck during steps by curing materials and needing to speed along.
Fast and small build steps: Having things you can do in an hour or two. Or ideally less, so you can make progress when you can.
Difficult to build dangerously: Look at the KR aircraft. Or the affordaplane.
Perform well: Have specs of performance you can.. expect. Have performance that's useful. Or at least.. predictable. (EG, look at the BD-4 build recomendations) Also have good.. communication to the pilot. Like stall strips and such to make sure the airframe doesn't sneak up on you.
Look good: We all have some idea of what looks good. Lots of us get blinded by "hey that works really well, so it must look good". That might mean tapered wings, when straight chord is easier. It might mean adding curves when straight sides are easier. Maybe this means putting some fairings on in places that "could be square" but don't look good square. Look at the DA-2c versus the DA-2a and B. Slab sides may be a reason we dont' see more BD4's out there.

... now i'm playing with sketches.
 

Sockmonkey

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Noooo, IMHO there is no real need for struts on a concept like that - with such a short span, and a (likely) very thick wing for this mission. Your original rendering is pretty close as-is, it may only need a tiny little more vertical area behind the CG to deliver sufficient yaw damping.

But otherwise it seems very much worthy of pursuing, which I think I may have said previously about this concept. The only significant 'drawback' that I can see is that you'll need a full tricycle gear setup, something along the lines of the Aerosport Quail. And this is not actually a drawback, it's a necessary evil that just happens to take a little aesthetics away from an otherwise very clean, sleek shape.

So building it as a cantilever wing that rotates on the fuselage, like the "Backyard Flyer" ultralight, would deliver a real-world advantage in storage and transport, setup time, etc.
Rotating the wing means I can get away with making the fuselage a bit longer as the tail will no longer be sticking out sideways. It's usually better to have too much rudder than not enough.
The reason I mentioned struts, (and this would just be a pair of teardrop cross-sections tubes) is so that the wing pivot doesn't have to be built to take weight and can be much lighter. Only needed to hold the wing during storage. One notion I have is to have the control yoke come down from the top like a hang glider bar so it can rotate with the wing and doesn't need to be unhooked from the elevons for storage.
 
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