Performance Requirements for Exploiting Microlift


Some people may question the adjective "high performance" ... but when your ultimate goal is a sink rate of 1 fps or 60 fpm, achieving a sink rate of 100 fpm is indeed high performance.  But sink rate alone is not the answer.  Many glass ships with very high L/D ratios achieve a low sink rate ... but at a relatively high speed.  The high speed of glass ships  makes it difficult to exploit the inner core of narrow thermals on weak days.  According to papers presented by Gary Osoba, your sailplane must meet several criteria to operate in the regime of microlift and microthreads of lift:

Spec:   Required for exploiting microlift ... mostly from Gary Osoba
100 fpm Very low sink rate 
 25 mph Very low speed at above sink rate 
Extremely small thermalling circle diameter (directly related to the speed squared ... v2
   26:1  A decent glide ratio at a respectable speed ... here the Carbon Dragon is weak. 
 20 feet Altitude loss during a 360 degree turn
docile stall entry and very rapid recovery ... Steve Arndt

Some people are skeptical about the loss per turn, but on a very overcast day with no lift, I have seen Osoba  complete four 360 degree turns while finishing a full pattern and landing at Elmira ... after a 200' autotow launch! ... where I drove the tow vehicle.

Carbon Dragon Drawbacks
Low maximum gross weight
Low Vne