I am attaching some pics of a French homebuilt microlight, the Autoplum by Maurice Guerpont. Guerpont is also known for an Biplum, a remarkably light (under 100 kg/220 lb empty weight) ultralight biplane.
I don't know much about this one, but the Guerpont Autoplum is a two-seat, low-wing monoplane of conventional wood and fabric construction with a two-stroke engine and fits well within the French ULM (microlight) category which allows a maximum gross weight of 450 kg for a two-seater (+5% with a ballistic parachute).
The Autoplum appears to be inspired by the Lacroix Autoplan series of tandem wing designs (think Flying Flea but with fixed incidence wings wings and conventional 3-axis control surfaces and controls). While differing from those designs by using a low wing forward, not a high wing, it does share one important characteristic...a relatively huge horizontal tail surface with almost 50% of the surface area of the main wing.
The Wikipedia entry and another page cite "considerable pitch damping" and "a very wide CG range" as the reasons for the big horizontal tail. That would track with what I understand of the Lacroix designs and suggests that the Autoplan might even be stable with the CG slightly to the rear of the center of lift. That would require the horizontal tail to be rigged as a lifting surface, which should be fine as long as the airfoils and relative incidence/loading are such that the wing always stalls before the tail.
What do folks think about the pros and cons of this configuration?
Cheers,
Matthew
PS--I'd be very interested in any other photos, videos, drawings, articles, etc. on the Autoplum that anyone might be able to share. I haven't even found a 3-view.
I don't know much about this one, but the Guerpont Autoplum is a two-seat, low-wing monoplane of conventional wood and fabric construction with a two-stroke engine and fits well within the French ULM (microlight) category which allows a maximum gross weight of 450 kg for a two-seater (+5% with a ballistic parachute).
The Autoplum appears to be inspired by the Lacroix Autoplan series of tandem wing designs (think Flying Flea but with fixed incidence wings wings and conventional 3-axis control surfaces and controls). While differing from those designs by using a low wing forward, not a high wing, it does share one important characteristic...a relatively huge horizontal tail surface with almost 50% of the surface area of the main wing.
The Wikipedia entry and another page cite "considerable pitch damping" and "a very wide CG range" as the reasons for the big horizontal tail. That would track with what I understand of the Lacroix designs and suggests that the Autoplan might even be stable with the CG slightly to the rear of the center of lift. That would require the horizontal tail to be rigged as a lifting surface, which should be fine as long as the airfoils and relative incidence/loading are such that the wing always stalls before the tail.
What do folks think about the pros and cons of this configuration?
Cheers,
Matthew
PS--I'd be very interested in any other photos, videos, drawings, articles, etc. on the Autoplum that anyone might be able to share. I haven't even found a 3-view.
