I have a request from one of you on my Berkik 3 flying wing video comment, it says to try adding landing gear on it, so this video is an answer to it, but instead using Berkik 3, I use B-2 Spirit model. This RC model plane also inspired by latest Freewing B-2 Spirit model and I enlarge it a bit to 2500mm. I always thought an RC B-2 Spirit is just an RC flying wing with landing gear, maybe just like a walking in the park, easy.
I choose twin EDF setup for the powerplant, I use 70mm 6 blades 4S EDF. I test them on test bench, and each of them can reach about 1200-1500 gram of thrust (without thrust tube) with 80A ESC. But it turned out far from it, just like my Mirage and F-35, 70mm 6 blades 4S disappointed me once again. I have 70mm 6S 12 blades EDF but only one unit. So I swap them with pusher props configuration.
I use twin DXW 3536 1200kv brushless motor for pusher prop setup, with 50A ESC and 4S battery (2200mAh), using 9 inch 3 blades propeller. Pusher props give enough power but still she couldn't take off from the ground, I suspect the front landing gear is not high enough to give the plane slightly higher AoA. This model is the heaviest model I ever build and fly, it's 3000 gram, yes it's finally fly by hand launch. The weight before adding ballast is 2500 gram and I had difficulty on finding things to be use for ballast, but I got the idea from real gliders, they use water as ballast on each wing. So I fill 2 bags of water each weigh 250 gram, and place them on the nose to balance on the CG. I copy the CG location from Freewing's model and resize it according to my model scale.
I also use drag rudder, the plane is very stable, easy to control and floating in the air. I'm not sure it's stable because of main the landing gear doors that always open or because of the drag rudder, I think the model is a success for me even though doesn't use EDF and can't take off from wheels, but until this video is uploaded I already in the process swapping landing gears with retract landing gear that use bigger proper wheels and higher.
Specs :
1. Wingspan 2560 mm / 100.7 inches
2. Flying weight : 3000 grams/ 105.8 oz
3. Wing loading : 26.2 gram/dm2 - 8.6 oz/sq.ft.
4. Wing cube loading : 2.4
5. Wing Area : 114.36 dm2 / 1773 sq.in.
6. CG : 58 cm / 22.8 inch from rear center point to the front
Electronics (pusher)
- 2x DXW 3536 1200kv
- 2x 50A ESC
- 2x Battery Lipo 4S 2200mah
- 7 x 9 gram servos (micro servo)
- 50mm, 2 x 60mm foam wheels
EDF :
- 2X 70mm 12 blades EDF
- 2x 80A ESC
- 2x 6S Lipo
Materials :
1. 5mm Foamboard/ Depron/ Polyfoam
2. 2mm Plywood
3. hot glue, UHU glue, CA glue
4. laminating film
Tools :
1. Hot glue gun
2. Heat gun
3. Covering iron
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B-2 Spirit Plans A4
B-2 Spirit Plans A0
B-2 Spirit Decal A3
Build Video on Youtube
