Canard TS Guide
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Orion Aircraft Corporation

Canard Troubleshooting Manual

For the

Falcon XP-B

Orion Optima

Phoenix

And other Canard type aircraft

Original Author: Romuald Drlik, MSME

Table of Contents

Takeoff………….2

Level Flight……..2

Power on stall…...4

Power off stall…..5

Landing…………5

Turning flight……6

Flight Mode: Takeoff

Problem:

Aircraft will not rotate at V1, (42 MPH IAS) or below V1.

1. Aircraft is too nose heavy. Check location of C.G.

2. Elevator travel is insufficient.

3. Canard Chordline is set to lest than +6 degrees to the waterline.

Or less than 3 degrees to the wing chord. (Decolage)

4. Ailerons are set too Positive to the wing chord.

Chordline of the aileron at the wingtip must be set between

0 and –1 degree to chordline of the wing tip. (ie. Reflexed)

5. Wing is rigged with insufficient washout.

Chordline of the wing tip (Geometric twist) is set to the

Wingroot chordline at an angle of ~4.5 degrees, minimum.

6. Wing was assembled improperly. Some outboard ribs may have been

Installed upside down. Check for proper aerodynamic twist.

(Change of airfoil shape toward outboard of the wing).

Problem:

Aircraft will rotate at V1 (42 MPH IAS, or below if light), but

Over rotates and must be pushed over, before canard stall occurs,

To maintain efficient climbing flight.

1. Aircraft is too tail heavy. Check location of C.G.

2. Decolage between canard and wing is well below +4.5 degrees.

3. Ailerons are set too negative. (0 to –1 at tip).

4. Engine thrustline is too negative. (-4 degrees is required).

5. Elevator hinge location is improper.

Flight Mode: Level Flight

Problem:

Aircraft will not maintain trimmed, level flight at 70-90 MPH IAS.

Hands off.

1. Canard is set to less than +4 degrees decolage (Incidence Difference)

between wing root and foreplane chordlines.

2. Ailerons are set to less than –1 degree to the wing tip chordline.

3. Ailerons are washed-in. Ailerons must be built with 0 to –1 Degree washout

Click here for  related link on Aileron Reflexing

at the wingtip station against its inboard station.

4. Aircraft is too nose heavy. Check location of C.G.

5. Engine thrust line is too negative. –4 degrees to the waterline datum is required.

Check power-off flight.

B. Aircraft is increasingly more nose heavy with increasing airspeed.

1. All of the above, plus wrong elevator hinge location.

C. Aircraft neutrally stable, to unstable in pitch.

Nose wanders up and down by itself without typical pattern.

1. Decolage and C.G. are improper.

2. Chordline of canard is well below +6 degrees to waterline, while C.G. is behind

optimum A.C. location.

D. Aircraft climbs even withs controls fully forward.

1. Aircraft is too tail heavy. Check location of C.G.

2. Elevator up reflex is insufficient. 1.5 inches at trailing edge of elevator root is required.

3. Ailerons are set too negative.

Click here for  related link on Aileron Reflexing

 

4. Engine thrust line is too negative. –4 degrees is required.

5. Wings are rigged with too much washout. –4.5 degrees are required.

6. Canard foreplane is set to too much decolage. +7 degrees to the waterline is nominal.

7. Winglet toe-in is excessive. Check wing geometry.

Angle between leading edge and wing tip rib must be between 107 and

109 degrees; both wings symmetrical. Higher values for docility and

yaw-pitch-roll stability, dutch roll reduction.

Problem:

Aircraft rolls too slowly.

1. Ailerons reflexed too much.

Click here for  related link on Aileron Reflexing

2. Control surface motion is obstructed.

3. Roll stiffness increases airspeed. (Normal)

Problem:

Nose drops when roll is initiated.

1. Canard decolage is insufficient.

2. Aircraft is too nose heavy.

3. Ailerons are set too positive.

Click here for  related link on Aileron Reflexing

4. Gap between canard foreplane and elevator is too open.

Problem:

Roll produces no adverse yaw. (Normal)

Roll produces strong adverse yaw even with heavy rudder input.

1. Ailerons are set too positive to wing tip chordline. 0 to –1 degree washout is nominal.

2. Ailerons possess improper twist. (Wash-in) 0 to –1 degree washout is nominal.

3. Aileron bellcranks are reversed on torque tubes. 2 x Sin function is required for proper aileron differential.

4. Wing geometry is improper. Check wing tip toe-in angle.

5. Winglets are twisted.

6. Rudders are set improperly on their stops. Winglets must not chamber outboard

7. Aerodynamic twist of wings is improper. Check for proper airfoil change toward wing tip.

Problem:

Aircraft rolls much faster to one side than the other.

1. Engine thrust line is out of tolerance laterally. 0 to 1 degree to the right is nominal.

2. Winglet toe-in angles are not symmetrical.

3. Rudder stops are not symmetrical.

4. Canard is not parallel with the wing.

5. Wings are built out of symmetry.

6. Aileron deflection is not equal on each side.

7. Control stick is not centered.

8. Aircraft is not symmetrical about yaw axis.

9. Ailerons are twisted and out of symmetry.

10. One wing is much heavier or has more area.

11. One wing is aerodynamically crude.

 

Problem:

Aircraft will not maintain "straight" yaw string (Slip ball) without constant rudder input.

1. Aircraft fuselage is out of lateral symmetry.

2. Winglet toe-in angles are not identical.

3. Engine thrust line is off laterally. Check power-off flight.

4. Wings are out of symmetry.

5. Canard is not parallel to the wings.

6. Rudder stops are not symmetrical. One rudder is extended too far.

7. Nose gear is not centered in flight. Check the centering springs

Flight Mode: Power-on stall. (Canard stall only)

Problem:

Stall is non-existent

1. Aircraft is too nose heavy. Check location of C.G.

2. Decolage is too high.

3. Ailerons are set too negative.

Problem:

Mild but noticeable nose drop after canard buffet onset.

1. NORMAL CONDITION! No problem.

Problem:

Strong nose drop, simular to "normally tailed" aircraft.

1. Canard decolage is set too low.

2. Aircraft is too tail heavy. Check location of C.G.

Problem:

Strong nose drop with simultaneous wing drop.

1. Canard decolage is non-existent.

2. Aircraft is extremly tail heavy. Check location of C.G.

3. Engine thrust line is improper, laterally and vertically.

Flight Mode: Power-off stall

Problem:

Stall is non-existent or extremely mild.

1. NORMAL CONDITION! No problem.

*** Anything else; See power-on stalls solutions ***

Flight Mode: Landing

Problem:

Aircraft bounces, and keeps on jumping.

1. Condition results from landing on "all 3" at once.

Do not hold stick fully back after running out of airspeed to keep the nose wheel off the runway! Land on the mains first!

2. Angle of attack is too low. Land slower.

Problem:

Aircraft "floats forever" in ground effect.

1. Approach at proper airspeed. (Slower) Use both rudders for drag braking during this procedure.

Problem:

Aircraft approaches steeply, with almost no flare.

1. NORMAL CONDITON! No problem. This is an efficient approach mode for modern aircraft.

Problem:

Aircraft "over flares" then "mushes-in" .

1. Aircraft is too tail heavy. Check location of C.G.

2. Pilot error! Do not over control.

3. Rudders "kicked" in abruptly.

Flight Mode: Turning Flight

Problem:

Aircraft is difficult to coordinate in the turn.

1. Aircraft is built out of symmetry.

2. Winglet toe-in is insufficient, or non-symmetrical.

3. Aircraft is too nose heavy. Check location of C.G.

4. Trim speed is set too high. Over 80 IAS.

5. Decolage between canard and wing is insufficient.

6. Ailerons are set improperly.

Problem:

Aircraft slips both directions.

1. Insufficient dihedral in the wings.

2. Insufficient washout in the wings.

3. Ailerons are set at too low of an angle to the wing tip.

4. Decolage between canard and wing is insufficient.

5. Trim speed is set too high. Over 80 IAS.

Problem:

Aircraft slips in one direction, skids in the other.

1. Engine thrust line is improper, laterally and vertically.

2. Wings are built out of symmetry.

3. Winglet toe-in is insufficient, or non-symmetrical.

4. Canard is not parallel to wing.

Problem:

Aircraft "tightens up" in turn, both directions.

1. Insufficient dihedral in wing.

2. Insufficient washout in the wings.

3. Ailerons are set at too low an angle to the wing tip.

4. Winglet toe-in is insufficient or non-symmetrical.

5. Aircraft is too tail heavy. Check location of C.G.

END

Click here for related link on aileron reflexing

 

Reproduced by permission from Romuald Drlik, Author, MSME

Copyright Falcon East 2001

Transcribed from .jpg to .doc format courtesy and efforts of

William Estes ( estes@frontiernet.net)

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