Virginia Creeper (oz14368)

About this Plan

Virginia Creeper. Radio control sport pattern plane, for .60 power.

Quote: "The main reason behind the design of the Creeper is what seems to be the lack of 60 sized, high performance, fun, sport pattern ships offered as kits in today's market. There does not seem to be much of an effort being made to improve this type of aircraft. At least it looks that way to me. As an example, the 60 class pattern designs in the good old days were an ongoing evolution to improve the performance of the breed. There was a constant pushing of the design envelope. Look at a few examples of what I'm trying to say, the series of Kwik Fli (oz6526), Kaos (oz6251), Phoenix (oz12671) and Mach 1 (oz5462), to name a few.

It well may be there is no longer a large enough market for kit manufacturers to make the investment or extend the effort for new sport pattern designs. After all, the kit makers are supposed to show a profit. Then again it may well be just an old dude's recollection of what used to be good. After all I am looking back at the 70's.

So, here we go! Let's take a look at what we have in the Creeper. The first thing I tried to do was to make an airplane that would be a load of fun to fly.

First, eliminate as much of the parasitic drag as possible by designing a low drag fuselage with a mid-wing position. This configuration should reduce the fuselage-wing junction turbulence, and will need smaller fillets. With the addition of leading edge 'strakes' to help smooth out the airflow between the wing and fuselage, there should be a substantial drag reduction at that juncture as well as improved turning at higher speeds.

The moments are a bit longer and the percentage of vertical fin and horizontal stab area are somewhat greater than the norm.

It is said that the most efficient wing planform is probably the elliptical. But the structure for this type of wing is more complicated to build and would probably be heavier. I went with what should be the second best, a wing with a double taper. The wing has a relatively high aspect ratio, a straight double taper and thin symmetrical airfoils.

The root is a NACA0015.COR and NACA011.COR at the tip, with two degrees of washout. The attempt here is to reduce tip vortexes and reduce drag. The wing is placed as close as practical to the fuselage centerline (thrust line) with zero incidence.

I don't want this article to become a lecture on model airplane aerodynamics. One, I'm totally unqualified to hold the class and, two, with most folks it would be as boring as watching paint dry! This is supposed to be fun! I would just like you to understand what's behind this design. I wanted to end up with an airplane that's fast, agile, responsive and easy to fly, and I think it was a success.

Wing (Built-Up): For the built-up wing, make all the parts before starting construction. All ribs are cut from 3/32 sheet. Attach the plywood doublers to W2, W3 and W4, with epoxy. Glue the 3/16 servo rail supports to W6 and W7. Carve and sand to shape the center, leading and trailing edge blocks.

Make the top and bottom spars using 1/2 x 1/4 and 1/2 x 1/8 balsa strips. The completed spar should be 1/2 x 3/8 from W1 out to W9 and 1/2 x 1/4 out to W11. If you wish to add a bit more strength to the spar, sandwich a length of 1/2 in wide carbon mat between the 1/4 and 1/8 strips. (I did this, but the wing will be plenty strong without it.) Spray the 1/2 x 1/8 strip with 3M spray adhesive to hold the carbon mat in place. Then assemble the spar using slow CA. Using 1/4 sheet, cut a strip 1-1/4 x 36 in, to make the inboard trailing edge.

Make the tubes from bond paper (for the servo wires) by wrapping the paper around a 1/2 in dowel, and taping the edge with Scotch tape. Remove the tube from the dowel and glue the edge down the inside of the tube with thin CA..."

Direct submission to Outerzone.

Scan by MarkD, cleanup by Circlip.

Supplementary file notes

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