Property of

CIVIL AERONAUTICS ADMINISTRATION

General Inspection Division

District Office 3 - 16

SERVICE INSTRUCTIONS

“MONOCOUPE”

UNIVERSAL MOULDED PRODUCTS CORPORATION

Monocoupe Airplane Division

Bristol, Virginia.

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ASSEMBLY AND MAINTENANCE

INSTRUCTIONS

(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

wing.

(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

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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

excessively.

(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.

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(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.

UNIVERSAL MOULDED PRODUCTS CORPORATION

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.