8 Ball (oz3289)

About this Plan

8 Ball. Free flight power model. 8 Ball from Model Airplane News issue 04-49.

Quote: "DON'T let the name fool you! The Eight Ball has a high performance and is a stable, consistent flyer. Although designed exclusively for Class A free flight events the model is large enough for small Class B engines.

Eight Ball was developed from a series of model airplane designs. The better points of several earlier designs are in-corporated in this model to maintain a more efficient and stable principle of de-sign and construction, thus making it a good contender in any A or B event. Much effort and planning was put into the development of this model.

The first test flights proved more than satisfactory - no adjustments were needed. In each successive flight the engine was advanced slightly and the flight showed improvement. The model has a very fast climb at about 70° to the horizontal and maintains this angle constantly with no dips or momentary stalls. Because of the high lifting stabilizer the model has a quick recovery to a hori-zontal glide, and the glide is smooth and slow. The ship does more than just glide, it shows definite soaring tendencies and will ride the weakest thermals. On its seventh test flight, Eight Ball soared for more than an hour with only a 12 second engine run and landed in Great Salt Lake, more than four miles from the point of takeoff.

Flying it is lots of fun, and it offers excellent contest material. The original has been adjusted to climb to the right and glide in left' circles or vise versa, showing favorable spiral stability with quick, easy adjustment.

The plans are to be scaled to full size before beginning construction. The pylon leading edge, wing and stabilizer ribs, and formers B to D are shown full size; this will help in enlarging the plans.

CONSTRUCTION. The fuselage, built around a 3/32 sheet balsa keel, is ex-ceptionally strong and will stand much abuse. This method was used to simplify the construction. When cutting out the keel allow space for coil, timer, condens-er, and battery box; then pin on enlarged fuselage plan. Cut out formers A to D from 3/32 sheet balsa, and formers B through L from 1/16 sheet balsa. Formers A, and E through L, are easily made by using a compass and drawing the cor-rect size circle directly on the balsa. A table of former sizes is given on the plan. Be sure to cut the formers to the exact diameter and notch out space for keel and 3/32 square stringers in order to assure a smooth planking job. Then glue half of each former to the keel. Shape tail blocking and glue into place. Cut two pylon leading edges from 3/32 sheet balsa and glue one on the pylon as shown on plan. Insert one motor mount of 5/16 x 7/16 hardwood through formers A, B and C, check for accurate align-ment. Now a 3/32 square stringer is glued into place.

After allowing sufficient time for dry-ing, remove the half-fuselage from plan. A metal strip and springs for pen cell connections are fixed in place as shown on plan. The ignition is then glued into place and wired securely. Recheck wiring so no trouble will occur in the ignition system after the fuselage is completed.

Assemble remaining half of the formers, tail blocking, 3/32 square stringer, and motor mount to the other side of the keel. Check motor mount alignment with the motor mount detail. This detail is shown for a Bantam engine. If another type engine is used the builder will have to make his own motor mount adjustment..."

Direct submission to Outerzone.

Update 22/09/2013: Added formers, thanks to jonfletcher.

Update 11/01/2019: added article, thanks to RFJ.

Supplementary file notes

Article.

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