[ARP]

Kai,

As you are located in Germany I wonder if you know of Norman Bernschneider's work in building Lilienthal glider replicas. Here he gets a HG/PG pilot (Lukas Bader) to try out the Derwitzer glider which also seems to have the hinged tail arrangement but with limit lines :- https://www.youtube.com/watch?v=cy1PUBjRCII

Tony

[KaiMartin]

As you are located in Germany I wonder if you know of Norman Bernschneider's work in building Lilienthal glider replicas.

I remember to have seen him in youtube clips. But I missed the one you linked with Lukas Bader as a pilot. So I got the impression that the replicas of Norman Bernschneider were not quite ready for flight. BTW, your flights with Stephan Nitsch`s replica of the Normalsegelapparat looked more convincing than what Lukas Baders got.

I compiled a short timeline of youtube videos.

2009 flight trial with a replica of Großer Doppeldecker (big biplane) straight from the museum:

He looks quite cautious as he runs the heavy glider down the meadow with his sun holding the tail.

2010 radio show with slide show:


2010 Running down the hill with a "Normalflugapparat":

Really just running.

2011 making-of the Derrwitzer:
[0hjNPVL7WEg[youtube]
In the basement.

2011 The Derrwitzer glider (live on TV):

Not quite convincing. He probably could have jumped further without the wing.

2013 Derrwitzer with Lukas Bader as pilot (short TV feature):

A whack and -- finally -- a flight! A short one, but still a flight.

---<)kaimartin(>---

[KaiMartin]

Arp,
thank you for the Bader/Bernschneider video. The whack on the first trial is a painful reminder of the dangers at launch. He would have loved to keep the nose up. But pitch-down was just too strong.

Ideally I would love to have maximum control on pitch, roll and yaw during the run. In reality, both aerodynamic and weight shift are affected by low speed.

Again, the bicycle provides an analogue: It is hard to keep balance at very low speed. So we routinely accelerate until the handle becomes effective.

---<)kaimartin(>---

[SamKellner]

Wow,
A maximum shipping package of <6ft
That would cut cost$ when ordering a new glider or parts.

[Frank Colver]

Back to Vectran for inflatables.

I was wrong on a couple of counts. Vectran is the fiber that is woven into the cloth, not Kevlar as I had thought. The fiber is made from a liquid Chrystal melt. For inflatable structures the cloth is then coated with polyurethane.

Here is a link on the manufacture's page to inflatable flight structures that used their Vectran product. Very interesting as to how much effort is going into developing these inflatable aircraft now.

http://www.vectranfiber.com/NewsInforma ... tions.aspx

Here's a rather amazing development, not very applicable to our multi use HG projects but I'm really surprised that there can be an inflatable structure that once inflated turns itself into a rigid composite structure no longer needing to have internal pressure. Read the company's statement below:

Rigidization technology: Through the addition of specialized resins, inflatable aerostructures can become solid composite aerostructures, eliminating reliance on internal pressurization to continue load support. As they are not easily reversible, these technologies should be considered for one-time use applications.

Frank C.

[JoeF]

Invited to the present movement: the world of origami engineering.


Also invited: the world of space structures.


And tensegrity.


Also graces from the world of kites.


The worldwide Project Kite supports the movement to have varieties of HGs in packs of 5 ft maximum length and maximum volume of 5 cubic feet. http://ProjectKite.info

=========================
But, Frank, the one-time use of the rigidization deal may have some hang glider use:
1. Suitcase glider taken to prison yard; open; inflate; let sun rigidize it; tow it up; glide out of prison.
2. ?

[ARP]

This one time assembly mimics the butterfly when it first inflates its wings and then they cure into wings capable of flight.

[ARP]

Kia,

Norman is probably too big to fly the replicas that he builds. Bringing in a lighter and experienced pilot is a good move to have a chance of flight. The glide angle of Lilienthal's gliders would have been around 4:1 at best. With the hill, shown in the video, being much shallower than that, there was little possibility of flight beyond a small hop.

Another builder of Lilienthal replicas is Stephan Boisvert in Canada:- https://sites.google.com/site/stephaneboisverthome/
His build quality is excellent and he has a good chance of getting them to fly. He is building the biplane version at the moment.

Although we have strayed from the 5ft-packed theme the Lilienthal design does fold reasonably well and Stephan Nitsch's replica could fit on top of a small car for transport.

Tony

[Frank Colver]

But, Frank, the one-time use of the rigidization deal may have some hang glider use:
1. Suitcase glider taken to prison yard; open; inflate; let sun rigidize it; tow it up; glide out of prison.
2. ?

How about a one time stealth HG flight from a closed site. Inflate, launch, Land, leave behind for media speculation as to how anyone got this rigid glider to the site without being seen?

I remember in the "old days" when certain HG pilots from a certain well known manufacturer (who is still in the business) used to pride themselves on making flights from places normally off limits. One restaurant on a hill's parking lot comes to mind among others. They were very good at rapid set-up and take-down of "standard" Rogollos and getting away before the cops arrived.

BTW- I neither condone, nor condemn, (taking no position) this behavior.

Frank C.

[KaiMartin]

Back on topic, this wandering Albatross demonstrates how to convert 3 m of wing span into a 50 cm length package in less than a second:


Scale this to the typical hang glider span of 9 m and you get just the package size this thread calls for.

From a usability perspective folding along joints is close to the best you can get. Unfold them and all parts are already in place. There is just one problem: The aerodynamics of the wing should not depend critically on rigidity and exact angles at the joints. Unfortunately, current hang gliders require exactly this. A straight, sweepless wing would be much less affected be by less than ideal joint properties.

Other methods to reduce package length would also work better in conjunction with a straight wing configuration.

---<)kaimartin(>---