The blog has been quiet for a while. Too quiet! Work has been a mess. I also attended a bunch of soaring events over the latter part of the year. I even spent a couple of weeks in South Africa! Anyhow, Christmas came up fast and I got to take a couple of weeks off. During my time off I was able to put in a couple days to get the Sbach completed!
Where I last left off in the previous build update I was with working on the emmpenage. In that post I showed the elevator setup. Unfortunately I forgot to take some pictures of the rudder install. Needless to say it went together pretty easily. One mistake was that I didn’t put in a collar with a set screw on the tail wheel wire as it came up to the brace under the rudder. This might put some extra stress on the “L” bend into the rudder but with a good mixture of micro balloons and 30-min epoxy it shouldn’t be too much of a problem, I hope.
The next step in finishing up the build was putting in the motor. Before I could do this I would have to build a motor box so that the electric motor would fit correctly within the cowling. Included in the hardware package were all the pieces to build a motor mount for electric motors. I assembled almost all the pieces except for the front and top. I did this so I could get in and mark on the firewall where to drill four holes to mount the box. After lining up the thrust markings on both the firewall and one on the motor mount I placed four holes equal distant around the box. All that I had to do was glue on the rest of the motor box and I was done.
Once the glue job on the motor box was completed I mounted it to the firewall. Now I was ready to attach a big hulking motor to yank this Sbach around!
The motor I choose was the HobbyKing NTM Prop Drive 50-60 Series 380KV / 2665W (AR Warehouse) which was wired to a HobbyKing YEP 100A (2~6S) SBEC Brushless Speed Controller (AR Warehouse). My dad picked me up a white 17×8 Xoar propeller with red tips from EspritModels.com. The 50-60 motor is a little big for this bird. I wanted to insure that I would have unlimited vertical so I picked the biggest motor that I could run a 6s battery. With the cowling just barely on the fuselage the motor was within a few millimeters of hitting the back of the cowl.
That white Xoar prop with red tips sure makes this a pretty looking plane!
When I’m putting together a plane that has wheel pants I always sit and think about if I should install them or not. So far I’ve always installed them. The plane just looks incomplete without them. Now, once I’ve done a flight they come off. With the Sbach I’m hoping that they’ll stay on a bit longer. The way these are setup and how I installed them should let keep them firmly attached the gear legs.
Now that everything was pretty much in place I decided to wire up all the electronics. Since the elevator halves are separate with their own servos I knew I was either going to have to get a reverser or do a fancy mix and use an extra channel. I decided to go with the latter. Setting up the elevator input and mixing in my Taranis X9D turned out to be pretty easy. Using separate channels also let me make sure that the limits and centering were perfect for each elevator half.
I took this quick video to show how ridiculous the throws were with everything set to 100% in the radio. Even the normal “sport” flying mode recommended is a bit much. I’ll probably end up taking off a little more on each of my settings.
So there you have it. I got the plane in July and finished it just before Christmas! All-in-all it was a pretty easy build. If someone had all the electronics in hand the plane could be reasonably be built in two or three days. Adding in the hardware changes and getting all the electronics took some time.
Oh, one more thing! I made a post containing the video of the maiden flight. Something I didn’t mention in that post was that when removing the 6s 5000 mAh battery I busted the middle brace on the top of the fuselage. I ended up taking some flat stock carbon rod that I used for making spars in foamie wings to shore up this area.
That should prevent any more busted bracing!