21st century Volksplane?

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erkki67

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I explained that.
It's so you can easily rotate the wing for storage and so you can re-position the pilot without messing with the CG
I understand this for storage, pivoting the wing and away with it.
You explained that it should be only a two axis bird, but I was wondering if the aft fuselage could be built sufficient strong to absorbe the twisting force, if the rear elevator was also used as an aileron, that means two independent panels right and left, controlled by a mixer.
The wohl aircraft would remain a 3-axis bird, only controlled by the tail volume.
 

Vigilant1

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There's no doubt that easy, AND cheap AND light is tough to do Maybe impossible. Somewhere there may be an acceptable set of compromises.
 

Topaz

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There's no doubt that easy, AND cheap AND light is tough to do Maybe impossible. Somewhere there may be an acceptable set of compromises.
And that set of compromises will vary between builder and designer. There's no one answer that's "best" for all. There's no one "best" set of compromises even for just the folks in this thread.
 

Sockmonkey

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I understand this for storage, pivoting the wing and away with it.
You explained that it should be only a two axis bird, but I was wondering if the aft fuselage could be built sufficient strong to absorbe the twisting force, if the rear elevator was also used as an aileron, that means two independent panels right and left, controlled by a mixer.
The wohl aircraft would remain a 3-axis bird, only controlled by the tail volume.
Possible, but sticking with two-axis also eliminates the pedals, which allows the pilot seat to be moved for optimal CG positioning with or without a passenger.
 

BJC

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does it meet the 2021 "easy to build" standard?
I would place more importance on having a kit that is "hard to do wrong" over "easy to build", assuming that easy to build really means that it can be built in minimal time.

But I am not the intended market; I'm not sure what today's children will want.


BJC
 

cluttonfred

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Here's a rough sketch of an Ercoupe-style wing with three aluminum tube spars, sheet aluminum over foam for the leading edge and aileron (supplemented with aluminum ribs on the ends if needed), and sheet aluminum diagonal main ribs.

I've shown sheet aluminum webs for the main spar but those could just as easily be light aluminum angle to form a truss. Square tube might also be an option for the spars, but there are so many more sizes available for round tube that nesting the latter is much easier if you want to reduce tube size from root to tip.

The Eppler 1214 airfoil was chosen for its generous thickness (19.8%) for a light and stiff main spar, good lift (Cl max about 1.6), and very low pitching moment to minimize torsional loads and trim drag.

This is all just conceptual, of course, and the thicknesses are exaggerated for clarity, but it does seem to me to pass the "unintimidating test."

Untitled presentation (5).jpg
 
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cluttonfred

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No offense, actually I'd like it better, since flat surfaces are easier to work with and the intersection of the flat spar webs with the round tubes and the wrap-around leading edge is a bit of a mess. We could even use thick angle for the spar caps and thin angle at 45 degrees to create a truss web. For bonus points, what about replacing the rear spar tube with an angle rotated 45 degrees or with a square tube?

OK.... if I managed to convince you to substitute one extruded angle for each of the the two main spar tubes, and left everything else the same.... precisely how horribly would that offend your sensibilities?
 
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Victor Bravo

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Truss web no-workie. When you rivet the sheet metal ribs (whether diagonal or square) you wind up wanting to rivet them to the spar webs. Not having a solid spar web becomes a complication and parts count boogie-woogie to attach the ribs.
 

cluttonfred

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Here it is with the angle spar caps and angle truss spar web. The blue foam would be keyed to fit between the corners of the spar caps and bonded to the leading edge skin, which is itself riveted to the diagonal ribs (not the spar caps).

My thought on the diagonal ribs was that they would be riveted directly to the vertical legs of the spar caps because the horizontal legs are doing most of the work. I was even thinking you'd want to drill lightening holes in the vertical legs (bottom half of top cap, top half of bottom cap) wherever neither angle truss web or diagonal ribs are attached. That said, I am not opposed to the idea of a sheet spar web possibly with lightening holes.

Alternatively, the diagonal ribs could be simple built-up A-shapes of aluminum angle in straight lines from the spar web to the rear spar. The airfoil outline and fabric support could be provided by more foam ribs diagonally with the A-frame ribs or chord-wise between them possible capped with sheet aluminum. But I do like the simplicity of Fred Weick's original approach.

Untitled presentation (7).jpg
EDIT: Updated image
 
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robertl

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Ok, I'm just throwing this out there because I've always liked the VP I and II, especially the VP II because of the roomier cockpit.. IF, building out of aluminum, could the fuselage be built monocoupe style, like Cessnas, Ercoups, etc.? I'm assuming it would need to be rounded to give it enough strength. To me, this kind of construction is pretty simple and strajgbt forward, you don't have to worry about temperatures for glue and such. I know from experience, aluminum is not without it's own unique challenges, such as trying to handle a large sheet of very thin aluminum by yourself, trying not to put a kink in it. OK, OK, I know, it won't be a VP, but it could be as simple as one. Just my thoughts. Carry on good people.
Bob
 

Bigshu

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Here's a rough sketch of an Ercoupe-style wing with three aluminum tube spars, sheet aluminum over foam for the leading edge and aileron (supplemented with aluminum ribs on the ends if needed), and sheet aluminum diagonal main ribs.

I've shown sheet aluminum webs for the main spar but those could just as easily be light aluminum angle to form a truss. Square tube might also be an option for the spars, but there are so many more sizes available for round tube that nesting the latter is much easier if you want to reduce tube size from root to tip.

The Eppler 1214 airfoil was chosen for its generous thickness (19.6%) for a light and stiff main spar, good lift (Cl max about 1.6), and very low pitching moment to minimize torsional loads and trim drag.

This is all just conceptual, of course, and the thicknesses are exaggerated for clarity, but it does seem to me to pass the "unintimidating test."

View attachment 112316
Here's a pic of an Airdrome aeroplane wing under construction.
No offense, actually I'd like it better, since flat surfaces are easier to work with and the intersection of the flat spar webs with the round tubes and the wrap-around leading edge is a bit of a mess. We could even use thick angle for the spar caps and thin angle at 45 degrees to create a truss web. For bonus points, what about replacing the rear spar tube with an angle rotated 45 degrees or with a square tube?
Without seeing a diagram, it's hard to say, but it sounds like the construction method used in the Hummel aircraft wings. They're light, strong, and rectangular (wingtip has a curve, but it's a simple detail). In fact, the Hummel designs are good examples of "Hey, I could do that!" construction, the only problem is they're all single seaters. But you can crank out an Ultra cruiser pretty quickly (See Dennis Brooks' you tube videos), and the H5 isn't much worse for time. Nice performance out of VW conversions too.
 

Aerowerx

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Ok, I'm just throwing this out there because I've always liked the VP I and II, especially the VP II because of the roomier cockpit.. IF, building out of aluminum, could the fuselage be built monocoupe style, like Cessnas, Ercoups, etc.? I'm assuming it would need to be rounded to give it enough strength. To me, this kind of construction is pretty simple and strajgbt forward, you don't have to worry about temperatures for glue and such. I know from experience, aluminum is not without it's own unique challenges, such as trying to handle a large sheet of very thin aluminum by yourself, trying not to put a kink in it. OK, OK, I know, it won't be a VP, but it could be as simple as one. Just my thoughts. Carry on good people.
Bob
You mean like the Hummel Ultracruiser?
 

blane.c

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When you think of the idea of Mr. Evans sitting down today (if he was still with us) and with a clean sheet of paper to start with, ... well the mind just boggles with the possibilities.
 

Topaz

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When you think of the idea of Mr. Evans sitting down today (if he was still with us) and with a clean sheet of paper to start with, ... well the mind just boggles with the possibilities.
That's the problem with designing an airplane from scratch. The mind boggles with the possibilities. ;)
 
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