Sushi 400

[joe yap]

Well since there's a new section, I thought that I may as well start it off by posting what I am currently building.

When I started the project, I didn't think much about posting a thread, and as such, the number of pictures are limited.

In 1995, I bought a copy of the March/April issue of the Electric Flighht International (EFI) magazine, which comes with a pull out plan for a sport flying plank wing, designed for speed 400 brushed motor. The design is simple and somewhat squarish and boxy, which makes the building quite straightforward. However, it also have some sexy curved wingtips, which although are quite eye appealing, may pose some small challenge to some builders.

I happened to have a 20mm size brushless inrunner motor and a 6x3 folder spinner/prop to go with, which I think is suitable for this project. This model has 43" wingspan and like most flying wings, it just requires 2 servos.

At this point, I have already completed the airframe construction, and moving on to the covering stage.

[joe yap]

Done with basic covering job. The wings are epoxied onto the fuselage permanently. The motor and the folder is fitted in place. Now about the rig and install the flight controls.

[joe yap]

The servos are rigged and installed in place. I made a mould to fabricate the servo covers from PVC sheets. Turns out pretty neat.

I got all electronics and equipment installed and bench tested the system on 3S. The 20mm inrunner produced quite some static pull on 3S, but I felt that it was working too hard, although I haven't take any current measurement yet. I'll try it on 2S later on.

[joe yap]

I added some trims to the white upper surface to aid visual orientation. My wife gave me the idea of bordered polka dots.

[msc]

Excellent quality work!
Will you have another fuselage for slope?

[joe yap]

Thanks, but I do not have another fuselage for slope. The wing section is not optimized for slope soaring. It is just a simple flat bottom airfoil with reflex. However, I can still fly this off Sedili.

[joe yap]

Maidened it this evening. Upon launching, the model pitched its nose up and I have to hold some down elevator during the climb. When I got enough height, I chopped the throttle and the nose started to pitch down. Apparently, the motor down thrust is not sufficient.

Since this model is to be flown with power off, like a glider, for most of the time, I trimmed it fly at throttle cut. I did a few small circuit before landing. Before my next launch, I programmed some mixing between throttle and elevator to mitigate the pitching moment. The next flight, although still not yet perfect, is much more manageable.

Overall, on 2S the climb rate, although is not spectacular, is decent enough for a sport model. What I really like about this model, is the glide ratio. It is quite a good floater and the landing approach pretty shallow, so a little more space is needed. With the motor cut and the prop folded, although you can't really compete with a DLG, will award you with a long and flat glide.

In a nutshell, I'm glad that I finally build this model, which I always wanted, although is already somewhet 18 years later.

[randomtask]

As usual, nice build man.

[joe yap]

Added some final touches......

[aeromodelling]

Nice work joe yap!!

[zennith]

it makes me hungry... sushi

[MicroHeli-Nut]

In a nutshell, I'm glad that I finally build this model, which I always wanted, although is already somewhet 18 years later.

This is really encouraging.



So this is more of a powered glider?

[Marco Cuenca]

Added some final touches......


"The finish is beautiful, what is the material that is tacking it down?
As to the flying, maybe if you equalize the center of gravity, and adjust the control surface throws, it might not pitch up as much on take off.
- Just saying?
"

[NUDGE]

Swee

As always Joe..nice work..