Archaeopteryx: the glider with feet!

[dedeleco]

We forget the weight of the plane and the passenger at the practical level !!
The stationary speed of descent is fixed by the weight of the airplane to balance the weight of the airplane by the lift, and the smoothness changes little with the speed proportional to the weight.
But at constant weight, if the speed increases the lift increases and the aircraft climbs back up after having descended too quickly (very visible on a paper plane launched too hard!), Then we act on the flaps to brake and maintain the speed constant and therefore the finesse decreases !!!

So you have to specify the conditions of these curves, otherwise it is not at a constant rate of descent, or it is by changing the position of the flaps, therefore the shape of the wing, which distorts everything !!!

But by changing the weight, and therefore the stationary speed, the fineness changes little.

[dedeleco]

previous error: lift and drag are proportional to the square of the speed and therefore speed proportional to the square root of the weight.

[Christophe]

You can click on the "edit" button to correct your message.

I did not understand your explanation: if there is a change in the aerodynamics of the plane (flaps out) necessarily the finesse changes ... but I do not think that this is the explanation ...

The concorde does not open its shutters at mach 2 ... well I hope for him

[loop]

Hello everyone,

Airplanes are all gliders when the engine (s) is stopped or idling. A low speed rotating propeller is even a superior aerodynamic brake than a stopped propeller.

The finesse in gliding is one of the characteristics of a glider but indeed the polar is more telling.

But by changing the weight, and therefore the stationary speed, the fineness changes little

In performance gliding, water is put in water ballasts, located in the wings. The increase in weight makes it possible to be more efficient at high speed, but does not change the smoothness. The downside is that we "climb" less easily in the ascents.
Here again it is a compromise to be found knowing that in case of difficulty, we can always drop water.

A cool link with drawings here:

http://www.planeur-stflo.net/pages/vavp ... inesse.php

A+

Gérald

[dedeleco]

It is a glider, not a motor plane which maintains speed by pushing more or less, but on landing, given its weight it (valid for all fast planes, it goes out of the large flaps to hold the air at low speed (250Km / h instead of 900Km / h, increased lift at low speed and reduced finesse), otherwise it falls like a ball at low speed (see catastrophes, flaps forgotten by stressed pilots) !!!
The wing changes are even more spectacular for supersonics.

The constant speed glider descends at such a speed that the lift balances its weight with the fineness of the wing, otherwise the speed is not constant.

If the speed increases, without changing anything on the flaps, the glider climbs up and if it decreases (for example at the end of the ascent), the lift decreases and the airplane relapses while regaining speed (if it does not stall!), phenomenon visible on any badly launched paper plane, which makes a roller coaster !!!

The constant speed is changed by changing the incidence of the wing (weight of the body moved) or its shape, flaps.


This glider keeps great finesse over a wide range of speeds, very practical to steer it, without losing altitude excessively
The weight is indicated and fixed 70Kg +10 Kg !!
A beautiful machine, great finesse doing everything, but what price ?? !!.

In the world of free flight, the Swift is considered like the Roll's.
His great life expectancy; its performance; the possibility of motorizing it.
And the most important:
Its ease / safety of piloting!
All this thrills enthusiasts who are lucky enough to own it and continues to make many others dream!
The Swift Light is a high performance foot-lift glider.
Designed to combine the advantages of hang gliding or paragliding with the performance and longevity of the glider.
It takes off or landed as desired, either as a glider or as a delta, while maintaining exceptional performance at high speed, reaching a fineness of around 27 points!
It is also able to hold very low speeds allowing it to be very "catchy" in thermal!
Although the device is completely free-standing with all the usual controls (such as flaps, elerons, winglets, airbrakes etc ...), it weighs only 48kg including harness. It is thus easily transportable on the roof of a car.