THE SHAPE OF THINGS
(Reprinted from Jacksonville, Florida Chapter 193 Newsletter) Struts, gear legs, and other essential
structural parts which are exposed to the slipstream create a certain amount of drag which will either slow the aircraft or require a greater amount of power to reach a desired speed. The amount of drag produced by these protruding objects depends greatly on the shape and, of course, the number.
The accompanying illustration will give an idea of how the shape has a
greater influence on the amount of drag than does the width. Column A is the fineness ratio which is merely the relationship of the length to the width. A fineness ratio of five means that the section is five times longer than it is wide. Column B is the resistance in pounds per 100 ft. of length per inch of width at 100 mph. Aircraft designers discovered early that exposed wires, struts, and the like created a great amount of drag. This is evidenced by the fact that many of the World War I aircraft employed streamlined wires and had faired struts.
THE SPORT OF SOARING offers a flying challenge, fun, achievement awards and competition. ATC'd and experimental sailplane kits available commercially. Send for free list. Join SSA and obtain the monthly Soaring magazine.
Associate member dues $9.00 per year; Member, $13.00. THE SOARING SOCIETY OF AMERICA, INC. Box 66071-X Loi Angelei, Calif. 90066
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MATERIALS AND PARTS AVAILABLE Enlarged information packets for the Baby $2.00. The 2T-1A Sports Trainer $3.00.
Both $6.00 Airmail.
Great Lakes Aircraft Company
25
Box 5974, Dept. B, Cleveland, Ohio 44101
EGG SHAPE
AIRPLANE SUPPLY CENTRE
18
(Ed's Western Aviation Sales Ltd ) 1104 Cambie Rd.. Richmond, B.C. Canada (A/C) 604-278-9804
R.A.F. 4Z SECTION
10.8 U.S.N. NO. 1 SECTION
COLUMN "A" - FINENESS RATIO COLUMN "B" - RESISTANCE IN POUNDS PER 100 FT OF LENGTH PER INCH OF WIDTH AT 100 MPH
COMPLETE STOCK HOMEBUILDERS SUPPLIES Certified Aircraft
SITKA SPRUCE
BIRCH PLYWOOD
48" x 48" Sheets
FOREIGN PURCHASERS — NOTE! All prices advertised in these sections are NET UNITED STATES DOLLARS. Foreign currency is generally not appreciated by the seller, and the best approach is to deal in INTERNATIONAL MONEY ORDERS payable in United States currency for the prescribed amount. Additionally, there is no way around the long time involved in shipping orders to foreign countries by surface transportation except for air ship-
ment. Those requesting air shipment had best send enough additional funds to cover the costs for such service, which are quite high from the United States.
Many of the suppliers to the amateur aircraft builder are operating on a marginal mark-up and can ill afford to absorb the extra cost of air mail shipment or air parcel post. Before you order the materials, you should write first to learn the specific and total costs which your order will entail.
.6mm 1.0mm 1.5mm 1.5mm 2.0mm 2 Omm 3.0mm 40mm 5.0mm
6.0mm
3 3 3 5 3 5 5 5 5 7
ply ply ply ply ply ply ply ply ply ply
Rough
Sawn $ 6.60 1x6 to 24' $ 6.50 1x8 to 24' $ 6.50 1x6 to 24' 1x8 to 24' $ 7.80 2x6 to 24' $ 7.15 2x6 to 24' $ 7.952x8 to 24' $ 9.10 Dressed $10.35 1x6 to 24' $11.00 1x6 to 14' $12.10 1x6 to 24'
Lin. Ft.
Reg. Reg. Spar Spar Reg. Spar Reg.
.50 .60 .90 1.10 1 00 1.80 1.15
Reg. .55 Spar .85 Spar .95
10% disc, on 20 sheets. Add $300 bundling charge on orders of less than 5.
ENGINES, WHEELS, A.M., BALSA, AEROLITE GLUE PRICE SHEET, DETAILS ON REQUEST 24-HOUR SERVICE ON ALL ORDERS. WE EXPORT
SPORT AVIATION
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