Reflex wings

[moonwrasse]

Why dont paragliders use reflex wings and paramotors do ?

Sorry if this is a really stupid question but its been bugging me for a while,

moon

[Guest]

reflex is a design feature where the rear part of the chord profile curves the other way to usual. It is not necessarily a wing type. Many paragliders do have a section of the centre of the wing with some reflex in it.

the reflexed part does not generate lift but acts as a stabilising mechanism.

Paragliding wings are "washed in at the tips" that is they are designed so that the angle of attack at the tips is higher than at the centre. This means that the tips stall first and in the event of asymetric collapse the collapse encounters increasing attack angle as it progresses past the centre and limits the collapse to 60%ish in theory.

Wings that use reflex right across the wing cannot also be "washed in" it would be like putting on the brakes. These wings rely on the reflex to stabilise them in turbulence so flying them at full slow "minimal reflex" makes them vulnerable to asymetric progress right across the wing.

A paraglider pilot wants to fly slowly in turbulence (they call it lift) they want a wing that will resist and limit collapse but retain as much lifting section as possible. A paramotorist wants a wing that will fly through turbulence and also be faster. Washin introduces more drag than reflex (in broad general terms)

so the wings have evolved for the specialised tasks. That is not to say you cannot successfully glide a reflex wing or motor a non reflex wing. Reflex wings tend to be fast but not have as good a glide as a comparable sized and aspect ratioed non reflex so for gliding pilots choose non and for motoring they choose reflex. (in broad general terms) In competitions the non reflex tends to win in gliding and the reflex tends to win in motoring so that kinda speaks for itself.

These are just my understandings and opinions. I am no great authority in the matter of wing design. I have flown both types in very strong conditions.