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by Dick Mathis
from Flying Models
February 1969
74in span
Tags: Glider F/F
:) all formers complete

Submission date: 28/05/2018
A backup copy has been saved on Outerzone as:
PlanID: 10147 | Filesize: KB
Credit*: Circlip, RFJ
Format:  •PDFbitmap

Plan file details

Tumbleweed. Competition A2 towline glider model. Quote: "I built the Tumbleweed in early 1967, using a set of Hypodemic Nerdel (oz8695) wing blanks I had started in 1962. The fuselage sides came from an FAI power fuselage I had started in 1961! This sort of scavenging always leads to a good ship. If you really want to see me foul up, give me several sheets of new, untouched balsa. I will go into a trance and cleverly shape these virgin materials into a 1937 Packard steering wheel - every time. I always save old model parts, knowing they will be needed someday. While I consider my American Crow (FM 1968) my No 1 Nordic now, I still prefer the Tumbleweed for windy conditions. My primary objective in building the Tumbleweed was to have a maintenance-free glider that would stay in trim regardless of conditions. Flying three or four events in a single day means you can't spend much time testing at a contest, so you must sacrifice some performance for reliability. Strangely, everytime I think I'm doing this, I end up with better contest times. There must be a moral there somewhere. My ship weighs 17.5 ounces now, which is about 3 ounces more than it is required to weigh. The extra weight is largely due to having a too short nose, which required more lead than I had anticipated to put the center of gravity in the right place. I've lengthened the nose on the plans to alleviate this problem. Also, the fuselage aft of the wing has been lightened on the plans. The extra weight on my ship seems to have helped its windy weather performance (a phenomenon predicted by several well-known Nordic fliers, like Mike Des Jardines, of the US, and Bo Modeer of Sweden, who by the way placed third in the last World Championships with an 18 ouncer). However, it seems to slightly handicap its performance in light thermal conditions. It will only do about 125 seconds in calm air, where it might gain 5 or 10 seconds if it were lighter. You be the judge of what weight you want. Built with light wood, the Tumbleweed will weigh about 14.5 to 15 ounces. Medium wood and a slick, weather-proof finish will bring it up to about 16-17 ounces. I recommend the latter, especially for less experienced fliers..." Tumbleweed, Flying Models, February 1969. Direct submission to Outerzone.



Tumbleweed - plan thumbnail image