The E-Flite Ultra Mini Stick is specified for our pylon racing series. A very nice all purpose airframe with no bad habits. Is a great little beginning pylon racer and when you are done racing just flip the switches to high rates and go have a 3D blast.
Note: If you assemble one of these make sure the wings, control surfaces and stabs are all straight first. Most are warped in any number of ways. A heat gun and patience is all you need.
This third airframe uses all the same components as the first two. As per the rules, the airframe is unmodified. On this one I finally put the motor inside which helps greatly with the balance. The Scorpion motor is a lot heavier than the one specified by the airframe manufacturer. The goal was not to add the extra 1.25 oz. weight I had on the tail of the first two. This way the battery could go where it is supposed to instead of shoving it as far back as possible. All up weight is 1lb, 13oz.
I put the motor inside behind the motor mount, the servos just ahead of the stab and the RX in the fuse behind the wing.
The motor mounting uses the cross mount supplied with the Scorpion SII-3020-890 motor. I drilled the outer holes and tapped them for 8-32 threads. New corresponding holes need to be drilled into the plywood motor mount for the 8-32 screws. Use the cross mount for a drill template. Also the center hole in the mount will need to be enlarged to allow for the collet on the motor shaft. When I installed the 8-32 screws, I used Locktite so I would not have to over-tighten them. The cross mount is very soft and new threads can strip easily. You’ll notice I had to cut away some of the bulkhead just behind the motor mount to make room for the upper two legs of the cross mount.
I added a 1/16 ply plate inside the fuse for the back of the PolyQuest 3S-2200 25C Li-Po battery to rest on.
The RX went nicely into the cooling hole in the bottom of the fuse behind the wing. This was not done so much for balance but the servo pigtails were too short to reach the place where the RX was intended to go. YES, I am using a 72 MHz because they are the cool thing now.
I cut holes in the sides of the fuse for the servos. I used Hitec HS-55 servos. Do some planning here. The servos I used butted into each other because of the narrowness of the fuse. One servo was moved up forward a bit to make clearance. I glued some scraps of plywood into the fuse in order to have something to put the servo screws into.
Notice the chunk missing from the forward section of the vertical stab. The stab was reused from one of the aforementioned crashed Sticks (darn bush).
I added a tail wheel to make ground steering easier. Just a piece of .040 wire and and a small wheel.
The wing is unmodified. Notice I use a differential aileron setup with my servo linkage installation. Helps with the turns. Make sure you wick in as much CA as you can into and around all control horns to keep them from coming loose..
Balance Point: 2.5″ back of the leading edge.
Ailerons 7/32″ UP and 3/16″ DN
Elevator 1/4″ UP & DN
Rudder 1/2″ R & L
Prop: APC 10 x 10 electric
Sources: Discount Hobby Warehouse has the airframes, and everything else you need, for a special, SEFSD Pylon Racing only, price of $74.95.
7644 Clairemont Mesa Boulevard
San Diego, CA 92111