Re: Aileron Repair Question

I would repair it with medium density balsa and do not use butt joints. Taper all the joints to get as much surface area as possible.

Use hardwood. You can cut a piece to fit, then apply slow-set CA to the hole and slide it in. Dr.1 Driver "There's a Hun in the sun!"

Hi,

I see you have received some good advise.

1) Taper (scarf) the joints between the old and new material so you have a larger gluing surface 2) Replacment with balsa and a aircraft ply doubler OR direct replacement with hardwood - if you use the hinge tape I mention below - medium density balsa is all that is required. 3) Check all of the other hinges 4) Good possibility that you have some aileron flutter

Here are a few things I would suggest in addition to the above.

1) Recheck the lateral balance of the aircraft after the repair - you may need to add weight to the opposite wing tip 2) On the underside of the wing, seal the gap betwen the trailing edge of the wing and the leading edge of the ailerons (and flaps if you built it that way). I found that the 2"+ wide, 3-M tape labeled as "Poly Packing Tape" works well. It is a little thicker and more elastic than many of the other tapes. This stops air leaks and can help eliminate flutter and improve the control authority. Here is the attachment method that works for me.

Clean the under surface of the covering with a strong detergent and then MEK at least 2" into the wing area and the entire surface of the aileron. Dissconnect the linkage at the aileron control horn. Reflex the aileron so that it is in full deflection toward the top surface of the wing and have a helper hold it in that position. Obtain an old wood prop and sand the entire edge of one blade so it is rounded and blunt. Any tool with a long, straight, blunt edge can work. Cut a strip of the poly tape that is long enough to cover the entire aileron hinge line. Apply one edge of the tape

1/2" forward of the wing trailing edge along the entire length of the aileron hinge line. Don't let the tape droop and touch the aileron at this point. Smooth the tape along the bottom surface wing trailing edge. Then - starting in the middle of the span and working out to each end - use the blunt tool to work the tape into the gap between the aft face of the wing tailing edge and the aileron leading edge. Again, don't let the tape touch the lower surface of the aileron as yet. Once the tape is smoothly adheared to the aft face of the wing trailing edge, start in the middle again and press the tape against the leading edge of the aileron. The final step is to fold the rest of the width of the tape back onto the lower surface of the aileron. This forms a uniform "V" in the tape at the hinge line that both seals the gap and acts like a continous hinge. If you want a little more fuel-proofing use a micro tip and wick a little thin CA along the fore and aft edges of the tape.

I fly my Ultra-Stick with the flaps and aileron set up for the "crow" function. I noticed an improvement of the roll rate once I taped the aileron hinge line. I have also used this technique on the elevator and rudder hinge lines on other models with even a bigger improvement in control authority.

What size engine are you using? Are you flying the Ultra Stick 1.20 with a gas engine (G-23 or G-26) or a 1.50 to 1.80 size 4-stroke? The aircraft was not designed to "go fast". If you have one of the higher powered engine mounted, you might get it fast enough in a dive to induce flutter. I have flown them with a G-26 and 1.20 without problems. However, one of the guys at the field mounted a Saito 1.80 and that was just enough extra power to cause problems. In any event, keep your eye on the integrity of the joint between the firewall and the fuselage on your Ultra-Stick.

Have fun,