Hobbyking Sbach v2 build log / review - Part 3


Almost there! Wings and tail are done, let's finish up this hottie and get her ready for the maiden!

Again this third and last phase took some effort and modifications to be completed, especially because the manual is pretty much worthless, so I had to find answers on internet and relying on my experience.

I decided to tackle the motor first, as it was the thing that required the most work:
First thing I did was to glue the motor mount, I used CA glue first and then reinforced the joint with 5 minutes epoxy. The structure is very rigid, so I have no doubts it will withstand the very powerful motor I chose.
When I went to install the motor itself I noticed that the shaft was not even reaching the cowl, so I had to space it out from the firewall about 12mm. To do so I used a series of washers , but I might cut some sections of aluminium tube and re do the spacing thing.
I then mounted the ESC with the separate BEC on the right side of the mount, because the heavier tail servo is on the left.


The motor mount is installed and glued with 5 minutes epoxy
Motor is in place, I needed about 12 mm of space between it and the firewall to allow the shaft to come out of the cowl enough to grab the spinner

For the cowl I used a method explained on Flite Test, where you place some tape on the sides of the fuselage to cover the cowl tabs, then you draw the centers, lift the tape, place the cowl where it needs to go, put the tape back down and drill where you originally drew the centers.


I put some tape on the sides of the fuselage to locate the center of the tabs for the cowl...
...then lift the tape, place the cowl where I want it, put the tape back and you have the location of your screws.

The landing gear gave me some headache, but nothing some thinking and tinkering could not fix. Basically the aluminium structure is much wider than the cutout section in the fuselage, so I had to file equally on both sides of the fuselage, reglue the fuse in that section to reinforce, and finally place the landing gear.
Also, the holes for the screws are not aligned with the blind nuts epoxied in the fuse at the factory. I had to enlarge the holes a tad, insert the screws on an angle and have them force their way in a bit. I know this is not ideal, but there was not much else I could have done.

The wheels and the pants needed some tinkering too, a lot of washers were used to space the nuts from the wheel and the wooden support of the pants, and still I have to figure out how to fix solidly the pants to the landing gear. Anyone?


The landing gear is too wide for its slot, and the holes for the screws do not align with the blind nuts epoxied in the fuselage. 
After fiddling a lot here is how I installed the wheels and the pants

Lastly I connected everything up to the receiver, and I programmed the radio to use flaperons and spoilerons to slow the plane down for landings, which apparently are pretty hard. We'll see.

The recommended CG is at 60mm from the leading edge, and to achieve that I had to push the 3S 2200mAh battery all the way into the cowl, so I had to build a tray to support it and to hold it in place.

Done! Now all I have to do is to wait for the rain and the wind to give me a break so I can go to the field and see how she handles! 

Electronics are installed, everything works perfectly! I chose to connect the ailerons servos to two different channels in the receiver, in order to have flaperons and spoilerons.
After checking the CG I had to move the battery all the way against the firewall to balance the plane
Here we go, ready to rip the sky!
All in all the build went along pretty easily, there were a few moments where I really wished the factory had been more careful when glueing things together, but for the price I paid I am ready to tinker a bit to make things work.
The quality is otherwise outstanding, and the model looks killer when built. She is of a decent size, even if on the edge of being a tad too small, next time I'll go bigger!

Maiden report:
Yesterday I went and flew this baby. AWESOME! I had to push the battery all the way into the cowl, and still I feel she could use some more nose weight.

I set Dual Rates and Expo as follows:
Ail / Ele D/R: 45%; Expo: 50%
Rud D/R: 30%; Expo 50%

Even with those settings the plane was very responsive, I can't wait to get a little braver and try some more manlier settings, the roll rate should be impressive.

The power from the motor is incredible, she took off at half power, and all the flight was done at 1/3 throttle, with some "bursts" at 3/4. And she scares the crap out of me as is :)

Now i can really say that she is currently my favourite plane. She is intimidating, but manageable. I have the impression that as soon as I will be ready to try some aerobatics with her there will not be any problem whatsoever. She flies as she is on rails: I put her in a position and she would continue without hesitations.

Here is the video, not extremely exciting, but my legs were shaking!