varg
Build cheap, crash cheap
The sportster is a classic that many in this hobby are familiar with but for those who aren't; it looks a bit like a fixed gear Spitfire with a straight wing, and It goes back to the early days of RC aviation. This airplane is based on the classic Sportster design, apologies to those who were expecting a 140% version of the stocky and simple FT Sportster. It's more comparable to a Great Planes Super Sportster, except it's about 16% larger and has a much more powerful motor.
Specs
Span: 56"
Chord: 9.375"
Dihedral: 4°
Length: 46"
Motor: Emax GT3520, 1150kv
Battery: 4S 5200mah 35C
Weight: I don't have a scale
I drew up some plans in inkscape with proportions based on old RC Modeler plans and a 3 view of the Great Planes Super Sportster, and made it as big as I could go using one sheet of foamboard per wing. The fuselage is too long to fit on a single sheet so the rear half had to be cut out separately and joined. It wasn't a FT simple build, but it wasn't hard.
The GT3520 next to my GT2215 (power pack C)
The wing is based on Nernic's speed wing build techniques and the template he publishes, but I kept the straight wing characteristic of the classic Sportster. The goal of making this a more complex speed wing instead of an Armin or FT wing was capability for high speed flight, because my speed wing Zero doesn't like slowing down so much I also installed servos for and cut flaps into the wing, but I ran out of extension leads so the maiden flight was flap free. It still seemed to fly well at slow speeds. Thanks to Nic for doing the trial and error for us and posting his videos and templates for the community to use.
I've only flown it once as of this post, and it isn't 100% finished, but the maiden flight went pretty well. It required more trim than I would like, particularly nose down trim, but I can still adjust the incidence and CG to figure out what's right for it. Other than that it handled pretty well. I'm looking forward to flying it again trimmed out and seeing if it handles as well as the classic sportsters, which were designed by much more experienced modelers. Once it's dialed in and has a cowl and canopy it'll be more aerodynamic and I'll throttle up and see what it can do. I haven't been to full throttle yet because of a spinner imbalance (now fixed) but this motor and a 10x5 prop on 4S is supposedly good for 6lbs of thrust, and I'm hoping that translates into triple digit top speed and unlimited vertical climb capability.
^note the thin rubber band I was using to secure the hatch flying off
Here's the video of the maiden flight:
Forgive the rambling at the end.
Specs
Span: 56"
Chord: 9.375"
Dihedral: 4°
Length: 46"
Motor: Emax GT3520, 1150kv
Battery: 4S 5200mah 35C
Weight: I don't have a scale
I drew up some plans in inkscape with proportions based on old RC Modeler plans and a 3 view of the Great Planes Super Sportster, and made it as big as I could go using one sheet of foamboard per wing. The fuselage is too long to fit on a single sheet so the rear half had to be cut out separately and joined. It wasn't a FT simple build, but it wasn't hard.
The GT3520 next to my GT2215 (power pack C)
The wing is based on Nernic's speed wing build techniques and the template he publishes, but I kept the straight wing characteristic of the classic Sportster. The goal of making this a more complex speed wing instead of an Armin or FT wing was capability for high speed flight, because my speed wing Zero doesn't like slowing down so much I also installed servos for and cut flaps into the wing, but I ran out of extension leads so the maiden flight was flap free. It still seemed to fly well at slow speeds. Thanks to Nic for doing the trial and error for us and posting his videos and templates for the community to use.
I've only flown it once as of this post, and it isn't 100% finished, but the maiden flight went pretty well. It required more trim than I would like, particularly nose down trim, but I can still adjust the incidence and CG to figure out what's right for it. Other than that it handled pretty well. I'm looking forward to flying it again trimmed out and seeing if it handles as well as the classic sportsters, which were designed by much more experienced modelers. Once it's dialed in and has a cowl and canopy it'll be more aerodynamic and I'll throttle up and see what it can do. I haven't been to full throttle yet because of a spinner imbalance (now fixed) but this motor and a 10x5 prop on 4S is supposedly good for 6lbs of thrust, and I'm hoping that translates into triple digit top speed and unlimited vertical climb capability.
^note the thin rubber band I was using to secure the hatch flying off
Here's the video of the maiden flight:
Last edited:
