durabol
Well-Known Member
-I am planning on building a plane that has a decent cruise of 150mph with a stall speed of 45mph (fit Canadian ultra-light regs). The ratio between cruise and stall speeds is a bit more than 3:1 so high lift device(s) need to be used.
-Junker/External Flaps: good CL (around 3) but may have too much drag.
-Fowler Flaps on Rails/Tracts: The Rutan Grizzly STOL plane used deep Fowler flaps that added 50sq.ft of wing area in a tri-wing configuration (best for CLmax I've read). The problem is construction and finding a design to copy as the patent doesn't give enough information.
-Slotted Flaps: Less CL (around 2.5) than Fowler flaps but easier to build.
-Slotted Flapperons: If had wide chord (.40c) or drop 30 degrees could get adequate CL (around 2.5) but unsure how safe that much flap deflection would be.
-Double-slotted flaps: On the Dyn-Aero MCR01 large double slotted flaps (CL around 3) that occupy approx 1/3 of the chord and 2/3 of the span achieve a 3.5:1 cruise:stall ratio. I'm not sure if plans are available and they may be hard to build. Does anyone know of a N. American equivalent of this plane?
-Fixed Slats add to CL (.3-.4) but have lots of drag, Automatic/Retractable slats are too hard to build.
-Vortex Generators: add a little to CL (.15-.2) and not much drag.
-Presently favour wide chord slotted flapperons dropped 20 degrees with vortex generators for a CL of around 2.5.
-Any opinions/corrections?
Brock
-Junker/External Flaps: good CL (around 3) but may have too much drag.
-Fowler Flaps on Rails/Tracts: The Rutan Grizzly STOL plane used deep Fowler flaps that added 50sq.ft of wing area in a tri-wing configuration (best for CLmax I've read). The problem is construction and finding a design to copy as the patent doesn't give enough information.
-Slotted Flaps: Less CL (around 2.5) than Fowler flaps but easier to build.
-Slotted Flapperons: If had wide chord (.40c) or drop 30 degrees could get adequate CL (around 2.5) but unsure how safe that much flap deflection would be.
-Double-slotted flaps: On the Dyn-Aero MCR01 large double slotted flaps (CL around 3) that occupy approx 1/3 of the chord and 2/3 of the span achieve a 3.5:1 cruise:stall ratio. I'm not sure if plans are available and they may be hard to build. Does anyone know of a N. American equivalent of this plane?
-Fixed Slats add to CL (.3-.4) but have lots of drag, Automatic/Retractable slats are too hard to build.
-Vortex Generators: add a little to CL (.15-.2) and not much drag.
-Presently favour wide chord slotted flapperons dropped 20 degrees with vortex generators for a CL of around 2.5.
-Any opinions/corrections?
Brock
