Undone (oz10963)


Undone (oz10963) by Bill Hebestreit 1970 - plan thumbnail

About this Plan

Undone. RC pattern plane for .60 power.

Quote: "Hottest thing in R/C pattern, was winner of several events at recent West Coast Championships. Undone 1, by Bill Hebestreit.

THE Undone 1 germinated in my mind for years, but I never got around to getting it on paper. Then two wipe-outs on successive weekends - groan, nothing to fly - dictated a crash program of design and construction.

Using a semi-scientific approach, I took the moments, areas and weights for the Kwik Fli (oz6526), Bar Fli (oz5544), Henchman (oz6942) and Sportmaster (oz2845) and plotted them with respect to CG, then with the thrust-line constant and, finally, on the basis of lateral area only with CG constant. And that's it for science.

Frankly, after I'd faired in all the lumps and scientific points it looked horrible. So I raised the thrust-line some, moved the wing up a little, added a few curves, erased all the extra lines and presto! Brand X was conceived.

With the profile established, I added structure details, borrowing ideas from other models. The somewhat unorthodox two-piece fuselage farmers are provided so the basic fuselage can be assembled upside down on a flat bench. Wing dowels are attached to the fuselage using a shear plate in the leading edge of the wing. In a crash, plan ahead. The plate shears at the glue points leaving the wing and fuse relatively intact. My planes have survived several dramatic landings this way.

The ailerons appear deceptively small for this size plane, but the tapered wing area is only 571 sq in. The airfoil is straight off Lou Andrews' Sportmaster with no improvements. Tail group is Kwik Fli III with the stab shortened 1/2 in and 1 in lopped off the vertical.

The name came about during the first flight. Takeoff required a nudge of up, then hands off for a 10-pointer. A touch of down trim and it's straight and level. So far so good. First turn, pops, on its back. Gotta slow down the ailerons. Three rolls now - wow - too fast, but on the wire. Loops? Beautiful. No corrections needed. How 'bout a loop with a snap 'n a half? Ease in up elevator. Now, stuff the sticks in the corner. What happened? That airplane just came all undone.

Let's try something safer like a knife-edge. After all, the main reason for all that fuselage area was the knife-edge anyway. I'll cheat a little 'n pick up the nose first. Now the roll. Now the rudder. Where'd it go? Would you believe a 100 ft-diameter rudder loop? This thing's just full of surprises.

Construction: I won't go through the usual admonishments about 'not for the beginner' because I don't care who builds one. Although the ship is tolerant up to a point, there are two absolute requirements: no warps and keep it under 6 lbs.

Select all your wood at one time if possible, and match up sets of sheeting for each wing panel and stab. Set aside until ready to use. Trim and glue sheeting just prior to use for minimum warping and tighter joints.

Fuselage: Prepare sides and add ply doubler. Trim the top edge and rear net. Leave a little trim on the front and bottom of the ply (this provides a little leeway for misalignment when joining with contact cement.) Trim net after joining, match up F3 and W1. Drill dowel holes and set aside.

Join the sides, F3 and F5. Set on top of work surface with F3 hanging over the edge of bench. Clamp, but do not glue tail post. Then progressively add F4 through F9. Using a square or triangle, align and glue tail post holding it square to the work surface..."

Undone, American Aircraft Modeler, January 1970.

Direct submission to Outerzone.

Supplementary file notes

Article pages, thanks to RFJ.


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Undone (oz10963) by Bill Hebestreit 1970 - model pic

  • (oz10963)
    by Bill Hebestreit
    from American Aircraft Modeler
    January 1970 
    60in span
    IC R/C LowWing
    clean :)
    all formers complete :)
    got article :)
  • Submitted: 20/02/2019
    Filesize: 867KB
    Format: • PDFbitmap
    Credit*: Circlip, RFJ
    Downloads: 400

Undone (oz10963) by Bill Hebestreit 1970 - pic 003.jpg
Undone (oz10963) by Bill Hebestreit 1970 - pic 004.jpg

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