3mm depron version of the wonderful little twin boom Eachine Micro Skyhunter.
Dimensions are similar to the original but with a slimmer fuselage.
1300mAH 3S battery and FPV gear.
CG best around 35mm.
The final version has a shorter nose, reinforced horizontal stab and rounded wing tips
This twin boom pusher is similar to the 1.3m Depron Spectre, however it has a straight 1.65m (65") x 190mm depron Armin wing and twin rudders.
1.3m Depron Spectre and 1.65m Twin Boom pusher
Initially it was designed it as a 1.8m light-wind slope soarer but didn't perform as well as I wanted. The longer tail booms and larger wing span made it too flexy and delicate. I was also comparing the performance to a motorless Phoenix 2000, which is a sensational sloper.
Shortened tail booms and wingspan stiffened up the airframe nicely and the addition of a motor fuselage turned it into an excellent FPV cruiser and medium wind FPV sloper. It tracks well in a straight line and has a decent glide angle but is quite agile like the Spectre.
Instead of using packing tape to cover the depron I used document laminating film, often referred to as New Stuff in the RC world. It is ironed on with a warm iron before bending the airfoil and fuselage, and works very well. It's tougher and easier to apply than packing tape.
Additional strengthening ...
6x1mm CF strip glued along the front of the elevator.
Heat bent UPVC brackets for the rudder to elevator joins.
I used twin rudder servos rather than one servo and a long vulnerable connecting pushrod between the rudders. Full length wing spar made from 2 Skyshark P4X spars joined with an internal CF rod joiner and epoxy.
The twin boom configuration means the motor doesn't need to sit up high, which means the fuselage can be slimmer.
The forward swept wings give amazing anti-stall characteristics and increased grip in the turns. I suspect when the wing tips flex upward they give positive feedback to the turn, similar to snap flaps. A swept back wing would do the opposite. It also looks very cool in the air.
This plane can fly slow or fast and is crazy manoeuvrable even without movable rudders, and it can balance in it's tail.
The wing build is slightly different to my previous style, with cut out ailerons rather than full span. Wingspan is 1.3m or 53" compared to IBCrazy's 40" and 48" versions.
I made a 200mm (8") x 20mm flat bottomed airfoil in two 700mm halves, then cut a wedge from each inner end to make the forward sweep when glued and taped together. The tips are about 45mm forward of the root. I also cut wedges off the wingtips so they were parallel. Naturally I cut them the wrong way first.
I removed some of the forward former in the spar channel either side of the join so the Skyshark P4X spar had a wider bend curve.
UPDATE: Here are a two more recent Depron Spectre videos. Some aerobatics on a rare calm 13th Beach day and some slope soaring at Beacon Point in a lovely 10-15kn NW wind.
