Completing the Build
"We're going to fly it on Sunday!"
said my girlfriend on Friday. Well, if she says we'll fly it, you bet we will. Better to get working on the plane again. I haven't done any work during the week, so the weekend was the only time remained.
First I glued in ailerons servos. No problems there, but I discovered, that the push rods I ordered are completely ridiculous -- they might find some use in full size jet fighter, but not in Bixler. They were too thick and extremely stiff -- and of course they did not fit into servo arms. Oh well, I'm sure I ordered them following some list of supplies posted here on RCgroups. Never mind, I will use the original push rods and clevises.
Other job was extending leads from ESC to motor. After some discussion on local forum I decided to disregard all the advice (overwhelmingly in favor of soldering the whole cable run without any connectors at all) and I made set of extension cables. Sure, it's sub optimal, but with my soldering skills it is surely better than trying to solder the whole thing in one.
Now, time to glue in the motor. This was one thing I wasn't completely sure about, as I discovered that snug fit of the supplied plywood firewall means there's quite noticeable axis offset to the right. At first I thought I must do something about it, but then I reread the manual to my previous SkySurfer clone (real manual, not that rag Hobby King includes with the plane) and they specifically mention the axis offset as feature. So I said OK, let's do it that way and glued the motor into the pylon (with cyanacrylate glue). Actually, the motor itself is outside of the pylon, since it does not fit. It's sure going to make for better cooling anyway.
I continued with gluing the fuselage halves together, then gluing in tail surfaces and finishing the job by equipping them with control horns (I used different ones than those supplied in the kit).
One of the greatest concerns I had was securing the wings. The SkySurfer and its clones are notorious for wings becoming loose or even falling off in mid-flight. My previous plane had the wings glued in, so this problem wasn't of concern. The plane would fit in the car trunk anyway. But that was then. These days the trunk is occupied by our puppy
, so the new plane must have removable wings. I decided to use strong magnets for holding the wings together. I have read some negative experience, but I have given it try anyway. I use three pairs of button sized neodymium magnets I had conveniently ready. I glued them into the wing with hot glue. They seem to hold the wing together fairly well, so we'll see how it works in the long term. Apart from this, I also reinforce the supplied carbon tube by inserting a smaller diameter tube inside. I never had trouble with my previous plane, but the wings flexed visibly on sharp pull ups. So maybe this will make it a little more stiff.
I also plan to reinforce the fuselage with carbon rod glued into the groove in the bottom, but since the time is short, I have decided to postpone this mod. And by the way, I haven't noticed any "tail wagging" that my previous plane exhibited upon actuating elevator.
OK, all is ready, plane seems pretty well balanced out of the box, though the more rear-ward position of the motor makes for very forward position of battery. Everything checks out OK. Time for the first flight. We load the plane and our white swiss shepherd pup
into our car and then head to my favourite flying location
. After arrival, I'm checking out the plane and the elevator does not move. Houston, we have a problem. It turns out the elevator control horn became unglued. Oh well. The plane goes back into the car and we go to out our puppy.
After we return home, I rummage through my stuff to find matching screws from a control horn set I bought last year but never used. Screw the glue, I'll bolt the control horn to the elevator surface. After making this repair, I head back to the field. The sun is setting when I arrive and it's a little more windy than I'd wish and also quite chilly. But what the heck. I apply throttle, throw the plane into the wind and -- we're airborne. With copious amount of throttle and against the wind the plane picks altitude fast. Everything seems to be alright, but the wind is too strong to notice if there are some subtler issues with the plane. When flying along the wind, the plane flies damn fast. On one low gliding (ie. no throttle) pass I hear menacing 'swoosh' sound. I don't recall that sound from my previous plane. The flying seems rather sharp to me, definitely in part due to strong wind and in part due to not flying for almost half year. After a while I go for landing -- I put the plane down gently, though not quite as near as I'd like. But safety first. I make another launch and another landing. But after seeing red light on my transmitter, which hasn't been charged for six months, I decide not to risk anything and pack my stuff. It's getting dark anyway and my hands are freezing. It's been successful maiden flight at any rate. Wings haven't moved at all, everything looks perfect. Looking forward to the next weekend.
Few pictures (sorry, I wasn't taking pictures most of the time).
Aileron servo installation. Original clevis and push rod, replacement control horn. Again, the original servos are little larger, so some EPP cutting was needed.
Fuselage halves being glued together. Notice the motor being outside of the pylon -- it doesn't fit inside.
Glued fuselage. If the motor axis seems a little crooked to you, then know it really is offset a little. They say it's a feature to compensate for some obscure force caused by the rotating downwash from prop.