Firewalls and Cowling

a flight test in which the airplane should be subjected to highspeed- ... at Torrance Municipal Airport,. Torrance, California. President Al Novotney opened.
738KB taille 6 téléchargements 128 vues
13

firewalls and Cowling FIREWALLS. A suitable firewall should be provided behind the engine-accessory compartment so as to isolate the powerplant from the remainder of the airplane. Firewall materials considered satisfactory without being subjected to substantiating fire tests are: (a) Stainless steel sheet, .015 inch thick. (b) Mild-steel sheet coated with aluminum or otherwise protected against corrosion, .018 inch thick. (c) Terne plate, .018 inch thick. (d) Monel-metal sheet, .018 inch thick. (e) Nickel-chromium-iron alloy (Inconel) heet, .015 inch thick. S~:nce the firewall is intended to isolate the engine from the airplane and to provide a fireproof b-.rricr, it follows that it should be suitably stiffened to resist, r.vithout undue deflection or buckling, the loads imposed by the operation and weight of controls and accessories attached thereto. Moreover, it should contain only the openings necessary to permit reiuired controls, fuel, ignition, and spray lines to pass through it, and these openings should be fitted with close-fitting grommets or burnings to resist the passage of flame. Rubber grommets are considered suitable only for the smallest openings. Steel bulkhead (firewall) fittings are recommended. Other fittings such as bolts, screws and rivets used as part of the firewall structure or for accessory attaching purposes should also be of firepproof material. COWLING. The cowling should have suitable provisions for drainag2 in flight and on the ground. The drains should be located so as to pr^vsnt fuel or oil from drippin •< upon hot parts of the engine, exhaust, or coming in contact •vith the exhaust discharge. These drains should also be located so as not to discharge upon airplane parts in such manner as to constitute a hazard. In most cases, small holes in the lower sections of the cowling are sufficient. Stiffener ribs and other structural members of the cowling should be designed and installed in such a manner as to preclude the possibility of fluids damming up in small pools. COWL ARRANGEMENTS - The arrangement of the cowling should permit all necessary inspections which may be required to maintain the airworthiness of the powerplant installation. Moreover, the removal of cowling for these inspections should not require the COWL ARRANGEMENT. The

use of special tools which may discourage conscientious compliance with routine inspection procedures. Inspection doors or easily removable cowling sections should be provided to permit frequent observation and easy removal of accumulations of foreign material, fuel, and oil. COWL CONSTRUCTION. Cowling around the powerplant and on the engine side of the firewall should be made of metal or other fire-resistant materials. Portions shielding the exhaust system should be made of a fireproof material such as listed for use as firewalls. The cowling should fit tightly to the firewall unless the airplane surface (that surface behind the firewall) within 24 inches of any opening in the cowling is suitably protected with aluminum or more fire-resistant material. The strength, rigidity, and attachment of the cowling should be sufficient to resist engine vibration and the loadings produced by critical flight conditions. The strength consideration of the engine nose ring, cowl skirts and panels, cowl flaps and cowl supporting structure should be carefully investigated, particularly in the larger higherpowered airplanes. Since the aerodynamic load on engine cowling is usually forward, the attachments on the cowling should be arranged to resist this load. In lieu of a stress analysis to determine whether ample strength is provided, comparisons with other similar cowlings may serve as a guide as to the airworthiness of the cowling under consideration. The final criterion, however, is a flight test in which the airplane should be subjected to highspeedflight maneuvers without failure or distortion of any portion.

Skeeter' in kit form, Bill Rodenberg and Hal Sanders rebuilding of the Heath 'Parasol' and many single and two-plane Stits 'Playboys' and Wittman 'Tailwinds'. TAO modified Stits 'Playboys' were flown in and displayed at the meeting. Ships built by Frank Smith of Fullerton and Lou Stolp of Compton. Lou gave a talk on his project, a general evaluation and points of interest and help

to those with similar projects under construction. It w as nice to introduce Art Williams, long-time member of Professional Race Pilots Ass'n., and E.A.A. experienced small airplane builder. He belongs to Chapter 14 of San Diego. Meeting was adjourned in favor of refreshments. Minutes submitted by Joan Trefethen, Secty.

Experimenter From Norway At Fly-in

Jon Christie, our member from Oslo, Norway ponders over a sign displayed in the "Little Audrey", reading "This Section of BarCI osed". Jan spent the week-end in Milwaukee, between his European airline flights, and proved a very likeable and popular member. ., ; •

Experiment To Find A!l Metal Production Costs

Experimental Aircraft Association L.A. Chapter No. 11 Minutes of meeting held July 24th at Torrance Municipal Airport, Torrance, California President Al Novotney opened the meeting with introduction of members and guests. Approximately thirty-five in attendance. Minutes and current correspondence were read. A general discussion of active projects took up the majority of meeting time. Each builder talked of his project, present status, progress, problems, etc. Such as the conThe Little low wing metal job was built from scratch. It version of the midget racer Parr will be two place tandem. Power will be a Continental 65 and Spel, pusher to a two-place sport later an 85. The ship will sport a T tail. Mr. Lasher said this plane by owners Art Beckington ship was started to find out exactly how much an all metal ship;: andGeorge Owl. Also the plans can be built for. We, here at headquarters will be looking forlor John Thorps all-metal 'Sky- ward to seeing those figures.