Introduction
The classic "Ugly Stick" and "Das Ugly Stick" are iconic designs that stand the test of time thanks to their simplicity and performance.
Just like the originals, my adaptation uses a minimal amount of material and requires very little time to get airborne. In order to simplify things as much as possible (and use electronics I had on hand) the design employs a short 29" wingspan that can be cut from a single sheet of foam board.
Much of the design is based on the Bud Anders and Larry Leonard balsa buildup from Midwest:
http://www.outerzone.co.uk/plan_details.asp?ID=5860
This, combined with the Flite Test build techniques and modern electric power results in a great little park flyer. As with any scratch build, let my design and experience be a starting point for your build. There is plenty to improve upon!
Materials/Specs.
- Fuselage: One Sheet of Dollar Store foam, hot glue, and clear packing tape
- Firewall: 1/16" hobby plywood (or similar)
- Prop: 8X4.5 Slow Fly http://www.hobbyking.com/hobbyking/..._2pc_CW_2_pc_CCW_Rotation_Flouro_Yellow_.html
- Motor: HexTronik 24g Brushless http://www.hobbyking.com/hobbyking/...rushless_Outrunner_1300kv_USA_Warehouse_.html
- ESC: Turnigy Plush 10A http://www.hobbyking.com/hobbyking/...amp_9gram_Speed_Controller_US_Warehouse_.html
- Batery: Turnigy 2S 500mAh http://www.hobbyking.com/hobbyking/store/__14970__Turnigy_500mAh_2S_20C_Lipo_Pack_US_Warehouse_.html
- Servos: Four Turnigy 9g http://www.hobbyking.com/hobbyking/...kg_0_10sec_Eco_Micro_Servo_US_Warehouse_.html
- Misc: Control horns, linkage stoppers, (4) 15cm servo extensions, pushrods, (2) rubber bands, BBQ skewer, tx/rx, 1/2oz weight, servo y-harness or extra tx channel for mixing
- Ready to fly weight: 260g
- Wing loading: 9oz/ft2
Build
Download the plans:
Download the plans from the links below. Get started by printing the templates, transfer them to foam, and cut out the parts. Red lines represent 100% cuts, blue lines represent score cuts, and yellow lines represent creases. Feel free to omit the scallops on the trailing edges for simplicity.
[Edit] if the download links below don’t work for you, there is a .pdf attached to this post.
- Adobe .pdf: https://drive.google.com/file/d/0B6...=sharing&resourcekey=0-J1J2W7cK7rfohSL3CUEing
- CAD .dxf: https://drive.google.com/file/d/0B6...=sharing&resourcekey=0-aqGepzLtsv1F8FqmuO65Hg
- CAD .dwg: https://drive.google.com/file/d/0B6...=sharing&resourcekey=0-JlpoZZKkExlV5WEG29duNw
Assemble the Wing:
The wing is a single piece design that is very easy to shape and results in a simple, zero-diehedral airfoil. Cut a double 45o bevel on the leading edge and gently crease the foam board with a BBQ skewer on the yellow lines. I like to use a straightedge to "break" the wing gently at the creases before folding. With the bottom wing surface on a table, gently fold the top of the airfoil over until the trailing edge rests on the table. Once the foam has accepted this position, unfold the wing and repeat the process and dry-fit the spar so that it lines up just forward of the second crease.
Make a reference mark on the bottom surface at the spar location. Unfold the wing and glue the spar to the bottom surface using the reference mark. Once dry, fold the wing permanently using a bead of glue on the leading edge, top of the spar, and trailing edge. Reinforce the center of the wing with clear packing tape. If you like, glue a short piece of BBQ skewer to the center section of the trailing edge to protect against the rubber bands that will be installed later.
Assemble the Fuselage:
The fuselage is another single-piece foldup. Just as with most FT builds, remove the foam in the fold joints leaving a single layer of paper. Fold the fuselage so that the "side-cheeks" are positioned next to the top and bottom faces of the fuse.
Install Tail Feathers
Cut a single 45o bevel on the stabilizer portion of the elevator and rudder to form a hinge. Due to size restrictions, I did not include locating tabs on these parts, they must be positioned by hand. The horizontal stabilizer sits in the notch on the underside of the fuselage. The elevator is glued directly to the top of the fuselage. Both hinge lines should line up with the aft tip of the fuselage.
Install the Firewall:
I deliberately left a firewall template off the plans because I find it easier to "scribe" the firewall to the fuselage. Cut a piece of plywood large enough to cover the open nose of the fuse and use the profile of the fuselage to trace the final shape. After trimming the firewall to size, drill a hole or cut a notch to pass the motor leads through into the fuselage. Install the firewall using hot glue on all four faces of the fuselage and reinforce with clear packing tape.
Install the Servos:
The Aileron servos are installed similarly to the FT Spitfire and Duster builds but you will need to notch out the bottom wing surface to accept a 9g servo. This may not be necessary if you decide to go with smaller servos. Install just forward of the spar.
The rudder and elevator servos are slotted into the fuselage near the tail. Again, I omitted cut lines on the plans to accommodate multiple servo sizes. To further simplify the design, omit the rudder servo and the score cut/bevel on the vertical stabilizer.
Instead of typical pushrod wires I used a BBQ skewer pushrods on the tail surfaces for rigidity and because I was low on wire. To make a BBQ skewer pushrod, cut a piece of skewer about an inch shorter than the distance between the control horn and linkage stopper. Cut two 1-1/2" long pieces of wire, make a z-bend in the end of one and leave the other straight. Use heat shrink to attach the wire to each end of the skewer, adjusting length as necessary. Once happy with the fit, drop a little CA into the heat shrink near the wire on both ends of the skewer. Once dry, this makes a nice rigid linkage.
Wire it Up:
At this point the build will begin to differ depending on the electronics used so proceed as you see fit. Install your rx and esc making all the necessary connections. If you are using the same electronics as I am, bear in mind that the battery and a 1/2oz weight will have to be positioned as far forward in the fuselage as possible to result in an acceptable CG.
Install the Wing:
The wing sits in the notch on the top of the fuselage, use a BBQ skewer to pass through the fuse just forward and aft of the wing. Use rubber bands to hold the wing on.
Tune
CG:
Install your battery so that the model balances on the spar. Again, the tiny 2s battery that I used was so small that I had to use an additional 1/2oz of lead along with the battery as far forward as possible to get the plane to balance. If you are using a larger battery, you're in luck!
Control Throws:
The setup I used for my maiden flight was very aggressive.
- Aileron: 3/4" up/down
- Elevator: 5/8" up/down
- Rudder: 1" left/right
Fly
Here comes the fun part. I hand launched the model at about 3/4 throttle into a 5mph wind and circled our local soccer field a couple times as I setup trims. Speed is not impressive on this 2s setup but there is enough power for aggressive climbs, loops, rolls and mild aerobatics. Stalls are gentile but control inputs (especially aileron) become weak at very low speeds yet there is solid control at a 3/4 throttle cruise. Flying in winds over 10mph would be a handful as the model tends to get blown around a little bit. However, I'm not at all disappointed in the overall performance of this budget parkflyer.
Is this a good BEGINNER plane? No, probably not, but it would make a good mild aerobatic "trainer".
Is this a good FIRST TIME build? No, probably not, but it would be great for those that have built one or two FT swappables or a modeler with traditional build experience that would like to try his hand at foam board.
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