LCRC Foam Pylon U-2 Pylon racer project
The first 2004 pylon race will be held Monday evening, June 7th at 6:00 PM. Pylon racers are gathering on Tuesday June 1st to trim and test their planes.
Aircraft Specifications
| Use the Lanier styro U-2 kit with a plain bearing engine. The O.S. 10 FP is suggested but any plain bearing (bushed) engine is OK. |
| Three channel control only. No ailerons (keep it simple). |
| Landing gear is optional but planes will be hand launched. |
| Racing will be done with 10% fuel which will be supplied free at the events. |
| Wings may be clipped or left stock. Minimum wingspan is 65 inches. |
| Low temp iron on covering or paint are optional. |
Here's an Acrobat document
detailing the construction
And here's an Acrobat doc detailing an electric version
Building tips
Tail surfaces: Measure 7/8 inch forward of stab TE at each tip. Split off elevator, attach hard balsa or spruce hinge surfaces. Bevel, hinge, etc. Rudder: Measure 1-1/4 inch forward from TE at top and 2-1/4 at bottom to split off rudder. Attach wood edges, hinge, etc. It's a good idea to inlay lite ply pads for horn mounts.
Wings should be clipped at the beginning of you're going to do it. The little hangy down doflotchies on the wing tips make it difficult to build a straight wing. Make two lite ply dihedral braces and stick them in obvious places. Stiffen the wing with filament type packing tape. The tape on the bottom of the wing must run unbroken from tip to tip for strength. It wouldn't hurt to place some hard balsa or spruce pieces in the wing LE and TE to withstand the rubber band crush. Join the wing halves with one flat on the table and a 7 inch block under the other (for a 66 inch wing).
Stiffening fuselage: Trace around joining face, top or bottom, onto 1/8 lite ply or 3/16 to 1/4 balsa. Make a horizontal spline or backbone to be sandwiched between the top & bottom of the fuselage. Cut out wood for servos, etc. before joining parts. Epoxy or odorless CA or Aliphatic resin glues all work well. Servos need to be arranged in line with rudder and elevator takeoffs on opposite sides. Make lite ply doublers for the outside of the wing saddle in order to spread the hold down dowel strain across more area. Cut the nose off flat 12 inches from front wing hold down dowel and notch back 2-1/2 and down 1-1/2 inches to form an engine mount area. Epoxy doubled lite ply rails for engine and slightly relieve inside diameter of fuselage to accept a small round fuel tank such as a Sullivan R-2 #401. Make it a snug fit. A lot of down thrust in the engine is a good idea with this type of plane, and 8 degrees is recommended. Start the engine notch in the fuselage even with the spline and 2-1/2 inches it will be about 5/15 higher to obtain about 8 degrees. This much downthrust prevents wild pitch changes coupled to the throttle.
Balance with the engine and battery pack location. Suggested balance point is 4-3/4 inches back from the wing LE at fuselage.
The purpose if this exercise is some laid back, relatively safe, cheap and easy pylon racing. Crepe paper streamer and combat competition could also be engaged. Very few rules and lots of leeway for design and material usage.