- Jul 29, 2005
- Orange County, California
How about folding the wing, aircraft carrier style? is that possible on a VP-size aircraft.
Milholland Double Eagle is pretty simple. VW powered.
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.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.
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.
For me one thing has become pretty well set in stone as a result of this thread: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."
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.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.