The X250 from SR Batteries

On Saturday, January 15, I started working on the X250. The following photos and notes were taken during construction.
I had shown the laser cut kit at the January EFO meeting. The members had many favorable comments. It certainly is a very good kit, and Larry really did his homework on this one. Built stock and with Larry's list of power system and R/C components it is a very good plane.
Unfortunately, I just can't seem to build a plane stock. I'll note changes that I made. There was nothing, nothing wrong with what Larry has done, but I've got a problem and just can't seem to build a stock kit. That is one reason I've never submitted a review to any national or international magazine. I just have to stick my fingers into and change it.

The wing went together easily and just as described in the huge and informative manual. The jig works easily. The laser cut parts were easily removed from the excellent balsa. I could not have hand-picked better balsa myself.
The only part that was a bit tricky was adding the landing gear blocks. I also created a second set of landing gear from 3/32" piano wire, as I am concerned about the durability of 1/16" wire provided in the kit. I'll fly it first with the 1/16" wire, but I've got the 3/32" wire in reserve. The difference between the two wire sizes is 0.4 oz.

My first modification is that I don't use "hinges." This photo clearly shows the technique that I've used for years on larger and small glow and electric planes. It is a bit time consuming, but very easy to do. It works, and I like it.

Tools: single-edged razor blade, metal yardstick 1 1/8" wide x 36 " long, covering iron

Step One: Cut strips of covering the width of the metal yardstick.
Step Two: Remove the backing from the two strips. Lay one on a hard surface glue face up. Lay the other down on top of it, glue face down and with about 1/2" overlap. Iron along the seam on one side, flip it over and do the same on the other side. Try very hard not to heat the area outside of the overlap.
Step Three: Using the metal yardstick, cut the strip of "hinge material" into individual strips as wide as the width of the yardstick.
Step Four: The movable surface (aileron, elevator, rudder) must be beveled at a 45 degree angle, top and bottom where it will contact the fixed surface edge.
Step Five: Now cut some 1/2" strips of the covering material and iron them on the surfaces where the movable and nonmovable surfaces mate. If you don't do this, you will see bare wood when the hinging is complete.
Step Six: Iron on the "hinges" to the movable surface alternating top and bottom along the whole surface.
Step Seven: Iron the hinges, now attached to the movable surface, onto the nonmovable surface alternating top and bottom.
Step Eight: Cover the whole structure (wing, H-stab or V-stab), movable and nonmovable surfaces.
Step Nine: Using a razor blade, cut the line between the movable and nonmovable surface and iron down the material between the surfaces. Done.
No you most likely won't cut the "hinges" when you cut the surfaces free. I've only cut one hinge in about 30 years of doing it this way and even that isn't bad, because you still have lots of "hinges" along the surface.
It is pretty easy, but can be tedious, but I still like it better than any other hinging method.

The second modification can also be seen. I moved the aileron linkage so that it will be inside the fuselage. This will also require modifiction to the fuselage later on.
A problem cropped up when I tried to solder the washers on the landing gear. I couldn't find them, so I had to substitute with some I had. Only ones I could find in the kit appear to be brass and too small. The manual calls for steel. I guess I could have misplaced them.

By the end of the second day, the wing is completely done, the horizontal stab needs its red trim and the fuselage sides are started.
This plane is coming together very quickly. Even though it is the weekend, I've not spent all of my time working on it. Day One was about 5 hours. Day Two about six hours.

The fuselage going together, along with the finished vertical and rudder. Everything went smoothly. Unfortunately, the battery pack I'm going to use, doesn't fit quite as nicely as it did on the plan. But that is not the kit's fault. It's mine. I didn't measure closely enough.

Covered and ready to glue together. The landing gear have been attached and removed. This is my favorite stage. It is when I can see what it is going to look like. Still lots more to do, and most of it won't be seen from now on.
Total weight with landing gear at this point is 9 ounces.

Glued on the wing, canopy, horizontal stab and vertical stab. Put sandpaper on the Maxx S400 motor mounts, mounted the motor and remounted the landing gear. I modified the hatch holddown and it can be seen behind the canopy. Masking tape can be seen holding on the bottom hatch behind the wing. The glue on the canopy is RC-56 and will dry clear by tomorrow.

I stopped by K-Mart and picked up some double-sided tape and some clear packaging tape to remake the battery pack. A quick dinner and then off to swing dance class with the wife. When I got home, I stripped all of the tape from the Sanyo 900SCR cells, including the tape I had wrapped around the top and bottom of each cell. I carefully retaped the pack and now it fits. There will be a picture of the pack later on. Not a lot done today, but the dance class is a hoot!

After work I went to Joe's Hobbies in Farmington and picked up some HS-81 servos. The HS-60's that I had on order didn't arrive. I also picked up a Maxx S400 drive for future use and some piano wire that falls between the 1/16" landing gear wire supplied in the kit and the 3/32" that I had already bent as spares. Spent the rest of the evening laying components on the plane, moving, thinking, laying, moving, and thinking. Nothing done that anyone could see, but I was fairly sure I knew what I was going to do about the radio installation.

Modified my original mounting for the elevator and rudder HS-60 servos to be used with HS-81's. Mounted the rudder and elevator servos. Made the rudder pushrod and trial fitted it. Found a good place for the receiver, and I'm reasonably sure my inside mounting of the aileron servo is going to work okay. Looking forward to finishing up tomorrow and making sure that it all works together.

Installed all radio components and pushrods. This turned out to be a much longer process than anticipated, as fitting the aileron servo turned out to be much more difficult than I had anticipated. It took several tries, and a couple of sets of pushrods, but it is working great now. Rudder and elevator servos and pushrods were easy. Placement of the receiver was an accident. It fell into the top area when I was working, and since it wanted to go there on its own, I let it stay there with some Velcro holding it in place.

It will be at least a month and a half before I give it a try. I'm NOT a winter flier, but I can be patient. I have plenty of other projects for this winter, but it is nice to know that I have a plane completely finished before the Midwest and EFO meetings. Usually I finish them the weekend AFTER the meetings! ;-)

I'm still not satisfied with the landing gear and have purchased some 5/64" piano wire to use, as the 3/32" gear I've already bent seem like overkill. The 5/64" gear should add about 0.2 to 0.3 oz. to the total weight of the plane, and that added weight is the weight stated in the Specs. Actual weight, when I brought her up for final photos was 29.2 ounces with the original gear.