[Courtesy of Pete Young ©1999, pwyoung "at" ix.netcom.com, February 1999]
Here's a collection of tips to consider when building an Olympic II. These items have been developed after building somewhere in the region of 14 Olympic II's over the years. My comments apply to the Airtronics kit version as I have not had a chance to look over the Whyte rendition yet. Pick the items that appeal to you. Keep in mind that thousands of Olys have been built with satisfactory results - these tips are ones that I have found "make it just a little bit better."
Fiberglass the interior corners of the fuselage from the forward nose block back to the wing compartment. 30 minute epoxy thinned with isopropyl alcohol works fine. This strengthens the forward fuselage from bursting open upon impact, and also strengthens the mid-fuselage for launch loads.
Now that the fuselage has been reinforced with fiberglass, the front fuselage bottom corners can really be rounded to improve appearance - the ply sides and bottom can be aggressively sanded almost to the glass. The noseblock can be tapered to a more attractive (and drag reducing?) 'point'. Drill a large hole in the noseblock prior to installation to install lead ballast.
To improve the appearance of the fuselage, I like to add a "Paragon style" canopy which replaces the sheet top hatch. Add triangular balsa supports at the tail to provide added support for the horizontal tail. Be sure to add sufficient material to the horizontal to have a wood-to-wood bond when covering material is removed from the stab.
Measure the wing incidence angle on the fuselage then reduce it by 50% to widen the speed envelope. As is, there is so much incidence that the plane is, literally, a "gas bag" in performance.
Install a ballast box to add weight at, or slightly in front, of the indicated CG. Learn to use it. Practice with it in calm and windy conditions. Remember - the Oly II builds "too light" IMHO and a little ballast will improve performance in both calm and windier air.
I don't like the way the nyrods "S" back to the control surfaces - this leads to friction, binding, and non-centering. Rather, terminate the nyrods inside the fuselage, bend a short "Z" bend in the wire linkages to clear the fuselage sides. Put the exit slots in the fuselage underneath the horizontal stab, not in front of it, to avoid weakening the fuselage. This way, the nyrods do what they do best: traverse back and forth in a straight line. Caution: do not use "Z" bends in faster or heavier aircraft and make the short section of the "Z" just long enough to clear the fuselage sides (to keep the linkage stiff).
The best towhook arrangement is the Paragon style: a Kirsch curtain rod hook that has been straightened, rebent into an "L", shortened with a Dremel, then screwed into a hardwood block. No machine nuts or blind nuts to loosen. The curtain rod hook has a coarse wood thread that resists loosening and the metal rod has never broken in my experience (which cannot be said of other, higher priced, loosening-prone, "contest" towhooks). Additionally, this towhook can be repositioned without tools and without access required to the fuselage interior - important for glass fuselages.
To clean up the fuselage from all those dowels sticking out into the airstream, fit two dowels facing fore and aft on the fuselage bulkheads - reinforce those with scrap plywood. You'll have to put tape on the wing centerline if using a two piece wing so the rubber bands don't fall into the crack.
Add doublers right where the stab L.E.s meet the fuselage. 1/16" ply or hard balsa will do. Put tapered edges on them to avoid stress risers.
Delete those curvy carved tip blocks which add weight and dubious drag reduction. Rather, use simple sheet tips at a 45 deg angle. Lighter, simpler, and the plane will respond better to rudder than with heavy tips.
Add one or two turbulator spars to the main panels to reduce that "sagging covering" look between the ribs on the main panels' forward section. On the balsa ribs supporting the wing joiner, double them up with 1/16" plywood. Unreinforced,, the balsa ribs will eventually fall apart due to the loads imparted by the joiner box during launches and hard landings.
Spoilers are not really necessary unless a ballast box is added. The standard lashup is unbelievably messy and inconsistent as its action varies with wing position fore and aft, and also rotating, on the fuselage. One option is to add a micro servo to each spoiler bay and have its servo arm directly push the spoiler open, with spoiler return accomplished by light rubber bands strung between pins in the spoiler underside and the rib bay.
Another more involved option is to permanently join the two main panels (this gets rid of the metal joiner rod and one piece ply dihedral braces are required) and plug a standard servo into the bottom of the wing center section - this engages thin Sullivan cablerods to mechanically "push and pull" the spoilers open and closed - no rubber bands, strings, or other hardware required.
I don't like the dihedral setup on stock Olys - fine for beginners but less so for intermediate flying. I have reduced the dihedral angle on the main panels by 50% and feel that the handling in turns is much improved.
Get rid of the rudder's forward overhang aerodynamic tab - this has been shown to degrade rudder effectiveness and at the flying speeds of an Oly II, the tab is ineffective in reducing servo loads. Use a ball-link at the rudder since the hinge line is tilted with respect to the linkage axis.
Build the tail feathers with Elmer's carpenter's glue, not C/A, since this provides strong, flexible bonds - very important when you start sanding, or covering, the tail pieces and twisting the structure. Watch out for that dowel joiner between the elevator halves. This has a nasty habit of breaking way unnoticed from an elevator with sometimes nasty results. Options include driving pins through the dowel into the balsa (somewhat labor-intensive), or adding a small swatch of light fiberglass cloth (easy with C/A).
If you want to lighten the tail, use a Dremel sanding drum to mill out lightening holes in the elevators. Mark evenly spaced hole centers before starting for best appearance. Add triangular balsa supports on either side of the vertical for added support.
Cover with Monokote, no other.
To minimize sagging between the fairly widely spaced wing ribs, cut the covering so that the "grain" runs spanwise. The "grain" direction is along the long direction of the covering coming off the roll. This won't make a difference on the wing's flat bottom or on the stabs, but will indeed on the wing's top surfaces.
Use Balsarite first (in the white and green can) to improve bonds.
A good sport finish for the fuselage is to fill the grain with two coats of nitrate dope, sanding smooth. Then spray with Krylon paint.
Contact me separately for a superior and reliable way to attach the wing to the fuselage with a nylon bolt. This does require the two main panels to be joined permanently.
©1999 Pete Young 42 Lawndale St. Belmont, MA 02478 <pwyoung "at" ix.netcom.com>
No reproduction without permission