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                                         General Inspection Division

                                             District Office   3 - 16










                                              SERVICE INSTRUCTIONS






                                              Monocoupe Airplane Division

                                                         Bristol, Virginia.





















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                                       ASSEMBLY  AND  MAINTENANCE



(A)  Attaching wing to fuselage.  If both wing and tail planes are to be

        assembled, do tail planes first.


        The Monocoupe wing is built in one piece, continuous from wing tip

        to wing tip.  It is attached to the fuselage at four points on the top

        longerons and is braced to it by the wing struts.


        To attach wing to fuselage:


        (1)   Raise fuselage to flying position.  Level it by placing a level on upper

        longeron over door or window (between front and rear center

        section wing attaching fittings).


        (2)   Raise wing above and slightly to rear of its position on the

        fuselage.  Tilt wing so leading edge is down and nose it gently into

        place in curve of windshield.  This should bring the four wing

        center section fittings directly above their mating parts on the

        fuselage.  As these parts fit very closely it will probably be

        necessary to use a screwdriver to help the wing fittings to slide

        over the fuselage.  The wing will not drop into place because of the

        close fit, but can be pulled down by inserting a punch or similar

        tool through the hole in each wing fitting and its mating hole in the

        fuselage, and pulling down.  Insert bolts with the heads outside.


        (3)  Attach wing struts to fitting at bottom of fuselage just forward of

        door.  Note that wing struts are left and right.  Assemble so fitting

        for jury strut (about midway of strut length) will be up or toward



       (4)  Into the outer ends of the wing struts are threaded forked end bolts

        be which the length of the strut can be adjusted.  A universal link is

        placed between this bolt and the wing fitting and this link must be

        bolted to the strut (with the head of the bolt uppermost) before

        attaching to the wing.  Care should be taken to see that the bolts of

        this universal link are not drawn up too tightly (so as to destroy the

        desirable universal joint action) but are just snug.  Vibration is then not

        localized which might cause failure of the forked fitting.  The right length    

        for the struts is such that when they are attached the wing is not

        distorted.  After attaching struts check incidence by placing a straight

        edge on the lower of several surface of several ribs between fuselage and

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        wing tip using a level to see that there is no incidence at any point.  Since

        the struts must be unbolted from the wing before they can be adjusted,

        several trials may be necessary before the right length is achieved.

        Whenever the strut length is altered, make sure that the head of the bolt

        through the universal link is on top.                                                                                                                                                     


        (5)  One degree of dihedral is built into the wing at the factory and if

        the struts are attached so as not to put any strain in the structure,

        no further rigging for dihedral is necessary.  The dihedral angle

        can be checked by stretching a string tightly over each spar from

        wing tip to wing tip.  Small blocks of exactly the same thickness

        should be placed between the string and the wing at the first rib

        inboard of the tip.  Measure the distance from the string to the

        wing at the four corners of the wing pyralin in the center section. 

        This distance should be 1-7/8” greater than the height of the blocks

        on the ribs.  If this distance is not the same at all four corners of

        the window, either the wing has been rigged with too much

        dihedral on one side (if both corners (left) are higher than the right)

        or with greater incidence in one wing then the other (if diagonally

        opposite corners give different measurements).  Any errors should

        be corrected by adjusting the length of the wing struts.


        (6)  When the wing is correctly rigged as above, it is desirable to

        “wash out” the right wing tip slightly to compensate for the torque. 

        This is done by decreasing the length of the right front wing strut. 

        Usually one of two complete turns of the adjusting bolt are sufficient.

        The torque adjustment can also be made by offsetting the rudder to the

        right or by a combination of rudder and wing adjustment, the rudder

        adjustment being made by means of the two springs attached to the front

        of the rudder pedals -- adjusting so that a little right rudder is carried.


        NOTE:  It is always advisable to correct for wing heaviness by

        decreasing the angle of incidence on the opposite wing tip rather

        than increasing the angle of heavy wing.  (Do this by extending or

        lengthening the rear strut on the side to be “washed out”.


        (7)  Put auxiliary or jury struts in place with adjusting bolt down. 

        These should be of such a length that they leave the wing struts

        perfectly straight.


        (8)  Connect aileron push rod in cabin to aileron bell crank mounted                                                                                                                 

        on left side of front spar.  When ailerons are in neutral position, control

        stick should also be in neutral position and long arm of aileron bell crank

                                                                                                                      Page  3


        should be vertical.  If stick is not in neutral, adjust aileron push rod.  If

        bell crank is not vertical, adjust aileron control cables, being careful to

        get approximately the same tension in the cables to the left of the bell

        crank as in those to the right.                                                                                                             


       (9)  Connect gas tanks to gas lines.  Install wing to fuselage and strut

        fitting fairing cups.


        (10)  Inspect all work done in assembly of wing for loose nuts, missing

        cotter pins, etc.


(B)   Assembling tail planes.  If both wing and tail planes are to be

        assembled it simplifies the tail assembly to do this first.


        (1)  On the Model 90A Deluxe, the stabilizer and fin are built in one

        piece and no adjustment is provided for either.  Set on fuselage

        with block under rear stabilizer spar and install lower streamline

        wires, the block permitting these wires to be started without

        bending them excessively.


       (2)  Remove block and fasten stabilizer to fuselage with two hold-down

        bolts on front spar and one bolt on rear spar.


       (3)  Push fin slightly to the left and install the right upper streamline

        wire.  Push fin to right and install left wire.  Avoid bending wires



       (4)  Line up stabilizer.  If wing is off, this can be done by laying a

        straight edge across fuselage at rear wing center section attachment

        fittings and sighting over it at rear stabilizer spar.  Adjust wires until spar

        is in line with straight edge.  If wing is on, measure from top of rear   

        stabilizer spar to bottom longeron at tail post and adjust until this

        distance is same for both sides of stabilizer and rear spar is straight as

        determined by sighting along it.


       (5)  Put in front stabilizer struts so front spar is in line with rear spar.


       (6)  Adjust upper streamline wires so fin is square with stabilizer. 

        NOTE:  Wire should have just enough tension to take up snugly.                                                                                                        


       (7)  Mount elevator on hinges, horn down.  See that it turns freely.  If it  

        binds, stabilizer spar is bowed, correct by adjusting wires.


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       (8)  Install elevator horn housing between sternpost and rudder.


       (9)  Mount rudder on hinges.  See that is turns freely.  If it binds fin is

        not in upright position and should be shifted in the proper direction by

        adjusting the wires.  


       (10)  Connect rudder control cables.  Adjust length so that rudder does

        not strike elevator when at extreme limit of motion in either direction.


       (11)  Install tail surface streamlines.


       (12)  Inspect all bolts and test action of stick and rudder pedals.


       (13)  Inspect turnbuckles for safety wires.  NOTE:  For convenience in

        reaching parts, it is well to raise tail a couple of feet when assembling.


(C)  Maintenance.  The airplane should be carefully inspected at periodic

       intervals with particular attention to these points.


       (1)  All control system bearings and control surface hinges should be

        kept well lubricated, and all excessive “play” eliminated.

             Aileron cable pulleys can be reached through the cover plates at

        the wing strut attaching fittings. 

             Aileron bell crank is located on front spar in cabin.

             Elevator bell crank bearings are mounted on lower longeron just

        back of seat  (see drawing FS 22000).

             Elevator push rod bearings should have grease applied if elevator

        seems to move hard.  These are two wood blocks in rear of fuselage.

        (See  F S 22000).

                Rudder and brake pedals have oil holes near top of upright member.

                Tail surface hinges have oil holes bored in them.

                Rudder cable pulleys located at bottom of fuselage in rear of seat

        (see drawing FS 22000).

                The Bungee trimming mechanism is reached be removing seat

        cushions, and should only be used for trimming in level flight - always

        release before taking off or landing - then no loads other than the air

        load will be felt on the elevator control.  The wheel hub bearings can                                                                                                                  

        be reached by removing outside cover plate.


       (2)  Brakes can be adjusted when necessary at wheel.




                                                                                                                      Page  5


       (3)  Tires should be inflated 11 to 13 lbs. for 6.50 x 10 tire and 12 1/2

        lbs. for 18“ x 8” wheels.


       (4)  Bolts should always be inserted with head uppermost.


       (5)  Keep lock nuts on adjusting bolts drawn down snug.


       (6)  Keep a shoe on tail skid, as if spring is used without a shoe, it

        will be damaged and require replacement.  If tail wheel is installed,

        grease frequently.                                                                                                             


       (7)  Take off wing fuselage streamline at least twice a year and inspect

        fittings carefully as they are very important.  Test bolt attaching wing

        struts to fuselage for play, and if loose put in oversize  bolt.  If wing struts

        seem to vibrate, check length of jury struts making sure they do not bow

        wing struts.


       (8)  Check landing gear shock cord twice a year for chafing.  The wide

        gear should have 9 turns ¾” shock cord on each side.  Considerable

        tension should be put in the shock cord when wrapping.


       (9)  Often times the brakes will grab excessively, particularly in wet

        weather.  The remedy is to taxi the airplane slowly applying the brakes as

        gently as is possible with increasing pedal pressures and throttle until

        finally you are just dragging the ship against full brakes with full throttle.

        Continue this until the glaze on the lining is burned off and the brake

        action will be soft and smooth.  While the above operation is being done,

        the airplane can be turned slowly, applying full brake suddenly to the

        outside of the turn -- the object of the whole procedure is to produce

        extreme heat and friction at the brake hand.















                                       Monocoupe Airplane Division,

                                                    Bristol, Virginia.


                                                Date:  Apr. 15, 1944


                                        SERVICE  BULLETIN  NO.  15


Monocoupe Models Affected:  90, 90A, 90W, 90AF (Army Designation L-7A),

                                                    90J, 110, 110 Special, D-145.


Subject:  It has come to our attention that in some cases the drain holes in

                the wings and control surfaces are improperly located so that

                moisture is trapped, causing glue joint failures and dry rotting

                resulting in looseness of the structural components in general.


                We therefore consider it imperative that the following instructions  

                be complied with immediately upon receipt of this bulletin.


                1.  Make a thorough inspection of the entire wing by removing the

                     inspection plates and checking the ribs for looseness, broken

                     glue joints, and dry rotting, checking false ribs for looseness. 

                     If any defect of this nature is discovered, then the sections of

                     the wing which do not have inspection holes must be opened

                     and the entire structure inspected.


                     If any excessive amount of these defects is apparent, then the

                     wing should be reworked and recovered.  If the structure is

                     found in good condition, special attention should be paid to

                     instruction No. 3 following, to prolong the airworthiness of the

                     entire structure.


                2.  Check the ailerons and flaps (if any) and if small wrinkles are

                     found in the fabric, a thorough check should be made for

                     condition of the structure.


                     Any fault found in the structure should be repaired immediately.


                3.  Check all drain holes, both on wings and control surfaces, for

                     proper location to allow maximum drainage and air circulation. 

                     If a drain hole is found to be over any part of the structure due

                     either to tightening, shrinking, or improper location, then a new

                     drain hole should be placed where moisture can drain and air will

                     be able to circulate.



SERVICE  BULLETIN  NO.  15 - Page 2                                 Apr. 13, 1944



                4.  Instructions Nos. 1 and 2 should be complied with at the end

                     of every six months period following the original check made

                     upon receipt of this bulletin, and a pertinent entry made in the

                     aircraft log book to that effect.


                     Instruction No. 3 should be complied with at the end of every

                     ninety-day period following the original check made upon receipt

                     of this bulletin, and a pertinent entry made in the aircraft log book

                     to that effect.



If you have disposed of your Monocoupe, please send this bulletin on to the new owner.