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Aerotec Software

Read Me File

Online Read Me file for all Aerotec software

All of these programs are supplied as Freeware and are part of the Public Domain.

The author accepts absolutely no liability for your use of this material and makes no direct or implied claim of its correctness or suitability for your design use.

All programs require MS-DOS compatibility

1. For a program to provide a print-out of the results, the printer must be connected to COM 1 or LPT1 port.

2. The Flight Envelope program was updated to indicate conditons under which the aircraft wing loading is 5.92 pounds/sq foot or less. In the situations it is likely that the Positive Manuevering Limit Load Factor (the maximum design 'g' factor) may be exceeded when flying at the Minimum Design Cruising Speed in rough air. The possible +/- g's [N(3) and N(in rough air are then indicated for comparison with n(l). This problem occurs mostly with light wing loading of the aircraft.

3. You need to know the maximum lift coefficient for your Wing. A low estimate would be 1,35, and a high estimate might be about 1.8 to 2.0; use your best judgement if you lack specific data. The value for this maximum C(L) is to be found from the 'polar diagram' for your airfoil, if it is available. A comprehensive questionaire accompanies each program; don't skip any answers except for the designer's name and aircraft name/model. You will also have to choose the Positive Manuevering Limit Load Factor n(l), i,e; the maximum design 'g'.

4. The stress program uses data in inches, weights in pounds, and a dimensionless ratio n(l). Omitting the wing weight will show an erroneously high stress in the spar since the wing weight does NOT stress the spar. The 'station' position requested is the distance (in inches) from the centerline of the fuselage out along the spar to where you wish to calculate the stresses.

5. The Flight Envelope Program uses wing area in sq feet, the gross weight in pounds, and the dimensionless numbers: the maximum lift coefficient C(L), and the Positive Manuevering Limit Load Factor n(l)

6. The Control Surface Maneuvering Forces Program uses dimensions in feet, square feet, weight in pounds and the dimensionless ratio the Positive Manuevering Limit Load Factor n(l).

7. All these programs are based on the comprehensive theoretical mater in Dr. Alex Strojnik's book: 'Low Power Laminar Aircraft Structures. The book costs $30.00; is available from his widow whose address is 2337 E. Manhatton, Tempe, AZ 85282, tele 1-602-838-1832.

8. The WT&Bal program was provided by Bill Renfroe and Allen Rossen (deceased) both of whom are/were good EAA members and active builders. The gust program came from Dr. Aragon who offered it for anyone to use.

9. If any program 'hangs up' use the 'Control' + 'Break' keys to restart. Remember, all these programs use approximations. They are simple and are in NO WAY FEA (Finite Element Analysis) programs.

10. Feel free to write or call me if you have and problems or any questions.

Wood Strength Data
Spruce Fir
Tensile Strength Parallel To the Grain Yield 5,300 5,900
Ultimate 9,400 10,900
Bending Strength, Full Cross Section Yield 5,300 5,900
Ultimate 9,400 10,900
Compressive Strength Parallel to the Grain Yield 3,530 4,220
Ratio of Ultimate Strength to Yield Strength in Tension 1.77 1.85
From: ANC-19, "Wood Aircraft Inspection and Fabrication", Vol. 2 (1951) as quoted in Strojnik's book.

Alluminum Alloys Data
Yield Tensile
Strength (psi)
Ultimate Tensile
Strength (psi)
Bare 2024T3 42,000 63,000
Alclad 2024T3 39,000 58,000
Bare 6061T6 35,000 42,000
Bare 7076T6 65,000 76,000
Alclad 7076T6 58,000 68,000

Aerotec Software
4116 West Frier Drive
Phoenix, AZ 85051-7319
(No collect calls please)

E-Mail: jwolfe@primenet.com

John L. Wolfe
Lt. Col. USAF (Retired)
BME Marquette University
MS University of Washington

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