cluttonfred
01-16-2014, 03:29 AM
Returning to one of my favorite topics -- unconventional French aircraft designs -- here is another one that proves that there is always another way to do things. Back in the 1950s Albert Gatard created a conventional-looking homebuilt monoplane with very unconventional controls. His low-wing, single-seat Gatard Statoplan AG 02 Poussin (Chick) was comparable in size, power (1200cc 25hp VW) and construction (wood and fabric) with other French homebuilt single-seaters of the era such as the Jodel D.9 Bébé and the Druine D.31 Turbulent. While not as common as the Jodel or Druine, the Poussin was (and occasionally still is) built in some numbers by amateur enthusiasts.
What made the Statoplan special was its very unusual control system. Basically, there were full-span control surfaces on each wing that were called flaperons but really acted as elevons. Roll control was conventional, as was the pedal-operated rudder, but pulling back on the stick lowered the elevons, thereby increasing wing camber, lift and drag. A connection between the stick and the otherwise fixed, all-flying horizontal stabilizer trimmed out the pitch change caused by lowering the elevons--the fuselage was said to stay within 4° of horizontal whether in the climb, descent or level flight. It’s unclear from what I have read whether or not the elevons could also be lowered via a separate control to function as flaps, but that certainly seems possible.
The aircraft was said to be very maneuverable, even capable of aerobatics, with excellent short-field performance yet docile enough for low-time pilots. According to Gatard, the drag of the lowered elevons in climb was offset by reduced fuselage drag. Whatever the reason, the little Poussin had performance in cruise equal to or better than it's contemporaries and, of course, visibility when climbing or landing was excellent.
All in all, it's an interesting approach. Personally, I wonder if a larger fixed horizontal stabilizer might obviate the need for the interconnected pitch trim for a simpler arrangement with the same benefits except for a slight reduction in speed?
Cheers,
Matthew
Sources:
Gatard Statoplan Poussin - Wikipedia, the free encyclopedia (http://en.wikipedia.org/wiki/Gatard_Statoplan_Poussin)
Gatard AG-02 'Statoplan Poussin' - Tourisme - Un siècle d'aviation française (http://www.aviafrance.com/aviafrance1.php?ID=9505&ID_CONSTRUCTEUR=555&ANNEE=0&ID_MISSION=0&MOTCLEF=)
Construire son avion (Gatard AG02 Poussin) (http://17ss.free.fr/)
Pou-Guide - Saintes 1958 : RASSEMBLEMENT R.S.A (http://pouguide.org/saintes-1958-r-s-a)
Gatard AG-02 Statoplan Poussin (http://www.airwar.ru/enc/la/ag02.html)
Heikkis' Silhouette Challenge - Page 257 - PPRuNe Forums (http://www.pprune.org/aviation-history-nostalgia/459476-heikkis-silhouette-challenge-257.html)
PS -- To my surprise I found an English-language article on the Gatard Statoplan in a 1959 issue of Sport Aviation. Enjoy!
What made the Statoplan special was its very unusual control system. Basically, there were full-span control surfaces on each wing that were called flaperons but really acted as elevons. Roll control was conventional, as was the pedal-operated rudder, but pulling back on the stick lowered the elevons, thereby increasing wing camber, lift and drag. A connection between the stick and the otherwise fixed, all-flying horizontal stabilizer trimmed out the pitch change caused by lowering the elevons--the fuselage was said to stay within 4° of horizontal whether in the climb, descent or level flight. It’s unclear from what I have read whether or not the elevons could also be lowered via a separate control to function as flaps, but that certainly seems possible.
The aircraft was said to be very maneuverable, even capable of aerobatics, with excellent short-field performance yet docile enough for low-time pilots. According to Gatard, the drag of the lowered elevons in climb was offset by reduced fuselage drag. Whatever the reason, the little Poussin had performance in cruise equal to or better than it's contemporaries and, of course, visibility when climbing or landing was excellent.
All in all, it's an interesting approach. Personally, I wonder if a larger fixed horizontal stabilizer might obviate the need for the interconnected pitch trim for a simpler arrangement with the same benefits except for a slight reduction in speed?
Cheers,
Matthew
Sources:
Gatard Statoplan Poussin - Wikipedia, the free encyclopedia (http://en.wikipedia.org/wiki/Gatard_Statoplan_Poussin)
Gatard AG-02 'Statoplan Poussin' - Tourisme - Un siècle d'aviation française (http://www.aviafrance.com/aviafrance1.php?ID=9505&ID_CONSTRUCTEUR=555&ANNEE=0&ID_MISSION=0&MOTCLEF=)
Construire son avion (Gatard AG02 Poussin) (http://17ss.free.fr/)
Pou-Guide - Saintes 1958 : RASSEMBLEMENT R.S.A (http://pouguide.org/saintes-1958-r-s-a)
Gatard AG-02 Statoplan Poussin (http://www.airwar.ru/enc/la/ag02.html)
Heikkis' Silhouette Challenge - Page 257 - PPRuNe Forums (http://www.pprune.org/aviation-history-nostalgia/459476-heikkis-silhouette-challenge-257.html)
PS -- To my surprise I found an English-language article on the Gatard Statoplan in a 1959 issue of Sport Aviation. Enjoy!