From the perspective of an inveterate pragmatist:

I think it comes down to operationality. Yes, the autoconnects add complexity. Yes, placing the wing panel separation at the station of maximum bending moment adds weight.

But what you get in return is a system of parts that allows for easy storage and transport, rapid assembly, and high reliability. That system has been proven to result in good soaring performance at the lowest possible cost in terms of operator fatigue. And that makes for a more enjoyable soaring experience. And when it comes down to it, quality of experience is what we should be trying to maximize here, not necessarily quality of performance.

It is easy to conceive of this or that adaptation that might result in greater performance for a no-holds-barred competition machine. However, all too often the result is a less robust machine that requires more work to assemble and prepare for operation. That's great if all you want to do is win prestigious contests and are prepared to either do or pay for the extra work required to campaign such an aircraft. It's less great for everyone else, and especially for those who buy such aircraft on the used market and find out what a pain it can be.

Thanks, Bob K.
https://www.facebook.com/pages/HP-24...t/200931354951

On Wednesday, February 5, 2014 1:29:19 AM UTC-8, J. Nieuwenhuize wrote:
Op dinsdag 4 februari 2014 22:53:33 UTC+1 schreef :

It seems it would make the structure more complex and heavier. I would guess it also would cost more to build a pylon wing glider.

I would expect the exact opposite. Looking at all the parts, easily a quarter of all the parts of a normal 15M sailplane are in the wing-fuselage intersection and the spar roots are a pretty beefy (and heavy) part since you have a joint at the highest loaded part of the whole structure. I don't have a weight breakdown at hand, but some earlier number-crunching yielded around 15 kg weight saved by carrying on the wing (and have 2 lighter joints outboard)

All those automatic connections add a lot of complexity and weight too and you can reduce their number by half. Not to mention spoilers (drag brakes) that can be in the middle of the wing since you're outside the fuselages "blocked zone" reducing the number of parts further.



One of the interesting things about glider design is that, even for open class, it's not really a free for all. The design has to comply with national airworthiness requirements and have acceptable flying characteristics for the average pilot. Compare this to an Unlimited Reno racer for example. I remember what Gerhard Waibel said about the ASW-12 in hindsight. It was something about learning how all new, hot gliders will become older gliders flown by less than top rank pilots eventually and you have to take that into consideration even when you're trying to make a world championship contender.



An excellent point. Yet, not certifying and having a homebuilt, development cost could be drastically less, though it'd still be wise to meet every requirement from CS22. Save France, to the best of my knowledge you can fly homebuilt sailplanes in most soaring-minded countries.



One. You need a fair pylon height to avoid interference drag in the gap

between the top of the fuselage and the wing's lower surface. I'd say

interference drag is relatively high on the Sunseeker shown he



http://www.solar-flight.com/



However I'm not an aerodynamics expert and have no idea what the optimum

height sound be except that its unlikely to be less than 10-15% of the

wing chord, think of the Wien for this pylon height, and that its one

problem the Ku-4 Austria didn't suffer from.



martin@ | Martin Gregorie

gregorie. | Essex, UK

org |



A bit of number-crunching suggests something like 0.5-1 root chord, so 1-2 feet for a typical single-seater.