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SM11188 Standard Modification Page : 1 of 6 Issue 1 Compiled : S Brown Approved : F Donaldson

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SM11188 Standard Modification Page : 1 of 6 Issue 1 Compiled : S Brown Approved : F Donaldson Mod No. SM11188 Standard Modification Page : 1 of 6 Issue 1 Compiled : S Brown Approved : F Donaldson TITLE : Main Wing Trailing Edge Flow Straighteners AIRCRAFT TYPE : Vari-Eze Mod Type: Retro-fit 1. Introduction The Rutan Aircraft Factory approved the (later to be mandatory) installation of leading edge vortilons on all Vari-Ezes in the October 1984 edition of the Canard Pusher ( CP 42 pages 5/6) to improve the swept main wing stall margins, increase visibility over the nose on final approach and enable reduced approach speeds without the risk of low speed wing rock or deep stall. The vortilons generate vortices over the main wing at high angles of attack that reduce lift-losing span-wise flow. There is negligible speed or drag penalty Flow straighteners positioned on the trailing edge of the swept main wing further reduce span wise flow at high angles of attack. It has been demonstrated that the addition of trailing edge flow straighteners enable the wing to produce more lift at a given angle of attack enabling lower approach speeds with no loss of view over the nose. The result is a reduced sink rate for a given airspeed and an increased margin between main wing and canard stall speeds. 2. Parts List Qty Part No. Description Source 2 SM11188-1 Outboard Fence Manufacture 2 SM11188-2 Middle Fence Manufacture 2 SM11188-3 Inboard Fence Manufacture White RTV Silicone Hardware store Flocked Cotton / BID / Aircraft Spruce Epoxy Resin List of related drawings / photos Drawing No. Title / Description Issue SM11188-D1 Drawing of Flow Straighteners dimensions SM11188-D2 Drawing of installation on main wing and fitting detail SM11188-D3 Photograph of Gary Hertzler’s fences installation on N99VE 3. Action Before fitting the flow straighteners, carry out a flight test according to the flight test schedule at the end of this document and record the parameters required. Manufacture and paint all parts listed according to drawings SM11188-D1 and SM11188-D2. It is important that the flow straighteners are in the correct alignment to the airflow, so it is necessary to obtain an accurate longitudinal reference to the wing. To achieve this, first stretch a string or wire taut between the trailing edge of each winglet/rudder. To provide a reference line at 90° to the string/wire, take a single sheet from a broadsheet newspaper and, while aligning the edges, make a 6 – 8” fold at one end. Drape the newspaper sheet over the string/wire so that the fold is along it and secure it with paperclips or staples, while still allowing it to be slid sideways along the string. Mod No. SM11188 Standard Modification Page : 2 of 6 Issue 1 Compiled : S Brown Approved : F Donaldson Making sure that the paper fold is aligned with the string, use one edge of the newspaper to mark longitudinal lines above and below the wing at the six points where the flow straighteners will be positioned on the wing trailing edge. Thoroughly clean above and below the wing at the positions marked. Depending on choice of flow straightener materials used, fit the flow straighteners into position and at right angles to the wing surfaces with a silicone bead or with silicone to the BID flange as detailed in SM11188-D2 and as shown in SM11188-D3. Jig securely and allow to cure for 48hrs before disturbing jigs. Re-check the flow straighteners’ alignment and attachment. If satisfactory, remove newspaper and string/wire. Amend the weight and balance schedule as set out in Section 5. 4. Flight Test and Special Inspections After installation, an LAA inspector must inspect the work done and, if satisfied, make a suitable entry about the modification in the aircraft log-book, including the LAA mod number and sign a Permit Maintenance Release (PMR). All fight tests should be carried out in accordance with the general conditions stipulated by LAA Engineering for the Permit Renewal Flight Test. Technical leaflet TL2.06 refers. Note the minimum test pilot experience requirement of a minimum of 100hr total time with at least 10hrs pilot in command current experience on type. It should be bourn in mind that the owner may not necessarily be the most suitable test pilot. Conduct flight tests, initially at less than MTOW and with the aircraft loaded for a mid CG position, progressing to MTOW and the full aft CG position if previous tests are satisfactory. Record all flight data according to the attached flight test schedule SM11188-R1. After flight testing, if applicable, establish a revised approach speed based on the data collected and amend the Pilot’s Operating Handbook accordingly. Notify the inspector that the aircraft has been successfully flight tested with this modification fitted and complete a Standard Mod Incorporation form (LAA/MOD 1) which must be kept with the aircraft records. Submit a copy of the SM11188-R1 flight test data sheet to LAA Engineering. List of related analysis or test reports Report No. Title / Description Issue SM11188-R1 Flight Test Report form 5. Weight and Balance Effects The modification will have a negligible effect. Weight Change Moment arm Moment Change 0.25 lb Approx. 150 ” Approx. 37.5 lb.in. Mod No. SM11188 Standard Modification Page : 3 of 6 Issue 1 Compiled : S Brown Approved : F Donaldson Mod No. SM11188 Standard Modification Page : 4 of 6 Issue 1 Compiled : S Brown Approved : F Donaldson Mod No. SM11188 Standard Modification Page : 5 of 6 Issue 1 Compiled : S Brown Approved : F Donaldson Mod No. SM11188 Standard Modification Page : 6 of 6 Issue 1 Compiled : S Brown Approved : F Donaldson .
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