21st century Volksplane?

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cluttonfred

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Like Topaz said, sure, but at what cost? Folding wings means more complexity and more weight. I think that's the real reason why so many small European designs (Jodel, Druine, Léger, etc.) have one-piece wings despite the hassle when building. It's the lightest option.

Personally, I value the idea of building in a small space (single-car garage or even a 20' shipping container) so I would split the wing into at least two panels for the building phase and would want the possibility to go back to two panels for shipping or long-term storage.

How about folding the wing, aircraft carrier style? is that possible on a VP-size aircraft.
 
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cluttonfred

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I have the plans for Leonard Millholland's Cabin Eagle, the enclosed Double Eagle with folding wings. It's a very straightforward, minimalist design. I have enjoyed gas welding steel tubes when I have tried it though I wouldn't trust my life or yours to my welds just yet. That said, the need to learn to weld would put off many first-time builders, so it doesn't fit the VP-21 concept.

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Milholland Double Eagle is pretty simple. VW powered.
 
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karmarepair

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I have the plans for Leonard Millholland's Cabin Eagle, the enclosed Double Eagle with folding wings. It's a very straightforward, minimalist design and I have enjoyed the gas welding steel tubes when I have tried it though I wouldn't trust my life or yours to my welds just yet. That said, the need to learn to weld would put off many first-time builders, so it doesn't fit the VP-21 concept.
The basic arrangements and planform of the Cabin Eagle are sound; but like you, I don't really have the time, equipment or inclination to learn gas welding. Spruce truss ribs and solid wood spars consume a lot of scarce time and hard to find materials, IMHO, and I have the jig to build ribs for this design sitting right beside me as I type this.

Tossing out an idea: Use the Cabin Eagle as a starting point for an aluminum tube and gusset fuselage/wing, flywheel drive full VW power. Wings would be based on Aerodrome/Graham Lee/DSK Honcho or the Boorabee examples.

The skill level required would be VERY low, better fitting the VP-21 concept.
 

Vigilant1

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If the plan for the 2 seater is an approx 600 lb empty weight AND aluminum skinned wings AND a wing area of 140 sq ft AND non-optimized tubular AL spar "caps", then I think we may find that something has got to give.
 

Topaz

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I mean this entirely in good fellowship and with no snark or malice whatsoever, but if you're at the point where you care if it looks more like a Tailwind or a Cygnet (or "Plane X") it's time to break out of this thread and design your dream plane. If there's one thing I know from being in HBA since 2005, it's that this thread isn't going to design YOUR dream plane for you, and there won't be a single design developed here that will make you and everyone else happy. The best a thread like this can do is to serve as a sounding board for ideas that can be used to develop your own dream "VP-21."
 

cluttonfred

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After 179 pages and 3,500+ posts over ten years, I don't think anyone expects some magical combination of traits to click with people and all or even most of us will say, "Yup, that's the one." This thread serves a reminder that aircraft can be relatively affordable and easy/quick to build but there are trade-offs. Like the old expression goes, "Good, cheap, fast...pick two." That doesn't mean that something in the spirit of the Evans VP-2 is "bad," just that are you are likely giving up something for cheap and easy. In the end, nothing will come of these discussions unless an individual or perhaps two or three people together decide to take the idea and make it a reality. And that's OK, the exploration of the idea is its own reward in the meantime.

If the plan for the 2 seater is an approx 600 lb empty weight AND aluminum skinned wings AND a wing area of 140 sq ft AND non-optimized tubular AL spar "caps", then I think we may find that something has got to give.
 
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Sockmonkey

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I guess in the end we can just have a catalogue of features and their pluses and minuses so a builder can just select the ones that suit them like when you make a D&D character.
 

Hot Wings

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I don't think anyone expects some magical combination of traits to click with people and all or even most of us will say, "Yup, that's the one."
For me one thing has become pretty well set in stone as a result of this thread:

If the VP-21 is to be built from scratch - and - via kits it will be of rivets and aluminum. This applies to Modern Primary Gliders as well............Autoreply may be right about composites for more advanced training gliders.
Wood is just too hard and expensive to source universally. Aluminum is more common and sheets can be rolled for cheap shipment.
Composites have a bad reputation and steep learning curve if made of moldless construction.
Glue together composite 'fast build' kits have most of the disadvantages of wood and the added development and tooling costs.

I prefere to work in composites so I'll probably never, given time constraints, add much to the 'universal' VP-21 concept. My interest are very similar, but to me the VP-21 concept is a little too constrained.
 

Vigilant1

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Obvious: The appropriate VP-21 construction type and material likely hinges on whether the design is to be built from plans, from locally cut CNC parts, or from a kit.

Keyed/tab-in-slot/printed-on indexing marks can assure alignment for rapid assembly with adhesives and tapes (avoiding the tedium of rivets), but problems with bonding reliability eliminates AL from consideration in this case.

Oratex can speed covering and reduce weight vs many other options, but it is unclear that a fabric covered plane would be as popular with builders in 2021 and onward as they have been in the past.
 
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blane.c

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For me one thing has become pretty well set in stone as a result of this thread:

If the VP-21 is to be built from scratch - and - via kits it will be of rivets and aluminum. This applies to Modern Primary Gliders as well............Autoreply may be right about composites for more advanced training gliders.
Wood is just too hard and expensive to source universally. Aluminum is more common and sheets can be rolled for cheap shipment.
Composites have a bad reputation and steep learning curve if made of moldless construction.
Glue together composite 'fast build' kits have most of the disadvantages of wood and the added development and tooling costs.

I prefere to work in composites so I'll probably never, given time constraints, add much to the 'universal' VP-21 concept. My interest are very similar, but to me the VP-21 concept is a little too constrained.
Wood substitution seems to be a popular topic about wood construction, for example "A-grade fir plywood" go ahead ... find some, so "B-grade" is acceptable then? or Okoume? or Mahogany? And if Mahogany which country of origin? It may be possible to contact a mill and have them make you some "A-grade fir plywood" but imagine the cost. The common substitutions that are used have advocates and detractors but nothing is really stamped "approved substitution" and that is just one product.

Glue substitution also a popular topic the aviation standard is Resorcinol glue but it requires tightfitting joints with the caveat that the joints cannot be glue starved. Kinda' vague. So translates to experience needed. It is common now to use various epoxy glue, there is no aviation standard for this that I am aware in wood joinery but it is likely most common in experimental building and is more forgiving of joint gap in the sense that it performs best with a slight gap, that is, there must be some glue in the joint and thus allowing a slightly larger tolerance. But again it is not a standard.
 
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