Archaeopteryx: the glider with feet!

bernardd · by **bernardd** » 28/10/10, 19:58

After the man flying a jet engine, Switzerland presents the leg glider !

Fortunately, it incorporates the parachute ...

Christophe · by **Christophe** » 28/10/10, 20:01

Aerodynamically it looks very much like a Swift (hang gliding) which I saw a demo at St Hilaire in 2007.

Can you be towed by an airplane with roller skates if you have no mountains nearby? : Mrgreen:

Capt_Maloche · by **Capt_Maloche** » 28/10/10, 22:56

EEXXXTTRRAAAAAAA!
enthusiasts for sure

A finesse of 28 !! and 130 km / h of Vne !!! : Shock:

Archeopteryx (2007): Finesse 28 to 55 km / h, stall speed from 30 to 35 km / h depending on wing loading, VNE of 130 km / h and a minimum fall of 0.44 to 0.51 m / s depending on wing loading

I just bought myself my first paraglider wing, its finesse is 9!

Christophe · by **Christophe** » 28/10/10, 23:46

Capt_Maloche wrote:I just bought myself my first paraglider wing, its finesse is 9!

Well done for the purchase! We need to talk about it in MP.

9 of finesse, at how many km / h of initial speed?

Because the smoothness without giving the initial speed does not mean anything ... I never understood well pkoi one gives it "raw" without relating it to the speed ...

A 747 surely has a fineness of 50 to 100 to 900km / h of initial speed ... : Lol:

Cuicui · by **Cuicui** » 29/10/10, 00:25

Christophe wrote:Aerodynamically it looks very much like a Swift (a hang glider) which I saw a demo in St Hilaire in 2007. Can you be towed by an airplane with roller skates if you have no mountains nearby?

Personally, I prefer the cheaper, lighter Swift, almost as efficient (finesse 24), perhaps more solid and which can also receive an auxiliary petrol or electric engine.
http://www.dailymotion.com/video/xbc1ga_swift_sport

highfly-addict · by **highfly-addict** » 29/10/10, 00:53

Christophe wrote:Because finesse without giving initial speed means nothing ...

But if Christophe!

Say, are you talking about speed / air or speed / ground?
: Cheesy:

come on I tease!

Obviously, talking about finesse only makes sense in a stabilized gliding configuration.

So hey, the smoothness is really stupid: it is worth "Vx / Vz" which is also equivalent to "d / h" or "d" is the distance traveled in still air and "h" the height consumed.

A boeing must have, at random, a finesse around 40, this means that in its best gliding configuration, for 1 m of altitude lost, it advances 40.
This implies a flight regime at the right speed, below or beyond, the finesse is degraded.

And to know the maximum finesse speed of a device, you have to know its Polar speed.

The archeopteryx seems to be a beautiful but fragile toy: http://www.youtube.com/watch?v=-j5N9SJjuU4

dedeleco · by **dedeleco** » 29/10/10, 02:23

A boeing must have, at random, a finesse around 40,

Certainly not, around 10, given the engines and the length to width ratio of the wings !!
The finesse is roughly also this ratio length on width of the wing, as for the sails or propeller blades or the blades of propellers of very powerful wind turbines!
So 40 is for high performance gliders with ultra-long wings compared to their width !!

By looking at the plane we know the order of magnitude of its finesse !!

http://fr.wikipedia.org/wiki/Finesse_%2 ... namique%29
http://en.wikipedia.org/wiki/Gliding_%2 ... lide_ratio

Read carefully:
http://heliciel.com/aerodynamique-hydro ... 20aile.htm

Indeed, the wing tip effects with their swirls are essential for an optimal profile moreover and therefore it is necessary to decrease to the maximum where the good gliders have hyper-long wings !!

highfly-addict · by **highfly-addict** » 29/10/10, 02:53

Ok after checking, the finesse of large ships is around 15 or even up to 19, which is still not bad!

Let myself be deceived by my finesse which stays below 10, that's for sure.

Christophe · by **Christophe** » 29/10/10, 10:35

Ok i was all wrong then

But so the finesse is given for what speed? Maximum finesse speed?

Planes generally have finesse between 8 and 15, rarely more than 20:

airliners have finesses between 15 and 20
the Concorde had a finesse of 4 at takeoff, 11.5 to Mach 0.95 and 7.3 to Mach 2.

So the smoothness decreases beyond a certain speed, why? Isn't lift supposed to increase "indefinitely" with speed? So she does not spend a maximum?

It may sound silly as a question but I never had a formal aerodynamics course ...

Christophe · by **Christophe** » 29/10/10, 10:48

I answer myself, finesse goes well with a maximum.

http://swiftlight.free.fr/caracteristiques/index.html

Found on a site dedicated to swifts http://swiftlight.free.fr/sujet/index.html

But I still don't quite understand why this maxi ... aerodynamic effect of delamination of the boundary layer or other?

Uh it's approved on the road ca (well it's Belgian):

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Archaeopteryx: the glider with feet!

Archaeopteryx: the glider with feet!

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