Proposed Method of Spinning an Aluminum Fuselage

assembly in the indicated manner. Being involved in ... the engineering knowledge for aircraft specifications and aerodynamics. ... much time involved in rigging.
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Proposed Method of Spinning An Aluminum Fuselage by G. B. Payne (EAA 44981) P. O. Box 71 Islington, Ontario, CANADA

HE PURPOSE OF this article is to throw an idea out T into the aviation field and see what opinions are generated concerning the feasibility of producing such an assembly in the indicated manner. Being involved in the metal-spinning business, it occurred to me that it shoulfl be quite feasible to spin sections for an aircraft fuselage. While we do have the necessary equipment and knowledge to fabricate such parts, we lack the engineering knowledge for aircraft specifications and aerodynamics. Working from past experience, I have come up with the following proposal. To spin a fuselage in sections, or stages, each stage would have its own bulkhead formed as an integral part of the skin. As there would be a welded seam in each section, a rivited-on section would form the keel, each being bolted together as shown in Detail 2. Each section would be bolted together, and so would be easily removed in case of damage, and could be replaced with a whole new section. Each stage would fit inside another, to form a fairly small shipping package. The advantages of this type of construction are obvious, the disadvantages not quite so. Being a perfectly circular fuselage, it may have undesirable traits in the stall or spinning attitudes. However, these have yet to be ascertained. This type of construction could be used to make various sizes of aircraft from single up to four-place, by adding additional cockpit sections in either tandem or side-by-side arrangement. The same rear sections would be used in all configurations. The wing and tail assembly would be attached through box spars. Wing panels would be removable for easy towing and storage. Various wing designs could be tried as long as the attachment points are the same in all cases. Because of

the potential high performance of the aircraft, the retracting-type gear may be advisable. Because the material has to be welded, alclad aluminum cannot be used. The fuselage sections would have to be made from 3003-H14 or similar grade aluminum, primed, and then painted or anodized to any color desired. Assembly of the basic fuselage structure could be accomplished by two people in a few hours, with not too much time involved in rigging. Construction of the wing and tail section would be fairly standard, except for the use of the removable type box spar. Advantages of Circular Spun Fuselage:

1. Even airflow over surface. 2. Lifting airfoil. 3. Easy assembly without jigs. 4. Removable sections for easy repair or replacement. 5. No separate bulkheads. 6. One row of flush rivets on outside skin. 7. No blind riveting 8. Spun sections packageable within each other for easy disassembled shipping. 9. Keel sections no more than fuselage sections in length. 10. Lower material cost. 11. Can be painted any color. Disadvantages of Circular Spun Fuselage:

1. Must have machine capable of handling size of spinning. 2. Sections must be stress-relieved after spinning, and heat treated to proper temper. 3. All surfaces must be zinc-chromated, or otherwise protected before assembly. 4. Weld seam must be done using proper equipment. 5. Weld seam must be properly ground. 6. Assembly holes must be drilled in right place. 7. Close-tolerance spinning necessary for good assembly of sections. 8. Completed fuselage must be painted or otherwise properly protected. This theory looks fine on paper. However, putting an actual aircraft together may be a different matter. If anyone has any comments, criticisms or suggestions, they would be gratefully received.

IELOEO SEM WIDE* KEEL SECTIOH

FORMED BULKHEADS

SPORT AVIATION

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