Aircraft flight trimming chart – HITEC Optic 6 User Manual

Page 22

Aircraft Flight Trimming Chart

2. Control

throws

Fly the model and apply full
deflection of each control in
turn

Check the response of each control
- Aileron high-rate: 3 rolls in 4 seconds;

low-rate: 3 rolls/6 sec

- Elevator high-rate: to give a smooth

square corner; low-rate gives approx.
130 ft diameter loop

- Rudder: high-rate 30-35° for stall

turns; low rate maintains knife-edge

Change EPA (for high rates),
and Dual Rate settings (for
low rates) to achieve desired
responses.

3. Decalage

Power off vertical dive
(crosswind if any). Release
controls when model vertical
(elevator trim must be neutral)

A. Model continues straight down
B. Model starts to pull out (nose up)?
C. Model starts to tuck in (nose down)?

A. No adjustment
B. Reduce incidence
C. Increase incidence

4. Center of

Gravity

Method 1: Roll into near

vertically-banked turn.

Method 2: Roll model inverted

A1. Nose drops
B1. Tail drops
A2. Lots of forward stick (down

elevator) required to maintain level
flight

B2. No forward stick (down elevator)

required to maintain level flight, or
model climbs

A. Add weight to tail
B. Add weight to nose

5. Tip weight

(coarse
adjustment)

Fly model straight & level
upright. Check aileron trim
maintains level wings. Roll
model inverted, wings level.
Release aileron stick.

A. Model does not drop a wing.
B. Left wing drops.
C. Right wing drops

A. No adjustment
B. Add weight to right tip.
C. Add weight to left tip.

6. Side Thrust &

Warped Wing

Fly model away from you into
any wind. Pull it into a vertical
climb, watch for deviations as

it slows down.

A. Model continues straight up.
B. Model veers left
C. Model veers right
D. Model rolls right

A. No adjustment
B. Add right thrust
C. Reduce right thrust
D. Put trim tab under left

wing tip *

7. Up/Down

Thrust

Fly the model on normal path
into any wind, parallel to strip,
at a distance of around 100
meters from you (elevator trim
should be neutral as per Test
3). Pull it into a vertical climb
& neutralize elevator

A. Model continues straight up
B. Model pitches up (goes toward top

of model)

C. Model pitches down (goes toward

bottom of model)

A. No adjustment
B. Add down thrust
C. Reduce down thrust

To test for...

Test Procedure

Observations

Adjustments

8. Tip weight

(fine
adjustment)

Method 1: fly the model as per

Test 6 and pull into a
reasonably small diameter

loop (one loop only)

Method 2: fly the model as per

Test 6 and then push into
an outside loop (one only,
fairly tight)

A. Model comes out with wings level
B. Model comes out right wing low
C. Model comes out left wing low

A. No adjustment necessary
B. Add weight to left tip
C. Add weight to right tip

Aircraft Flight Trimming Chart - Page 43

Aircraft Flight Trimming Chart - Page 42

To test for...

Test Procedure

Observations

Adjustments

9. Aileron

differential

Method 1: fly model toward

you & pull into a vertical
climb before it reaches you.
Neutralize controls, then
half-roll the model.

Method 2: fly model on normal

pass and do three or more
rolls

Method 3: fly the model straight

and level and gently rock the
aileron stick back and forth

A. No heading changes
B. Heading change opposite to roll

command (i.e. heading veers left
after right roll)

C. Heading change in direction of roll

command

A. Roll axis on model centerline
B. Roll axis off to same side of model

as roll command (i.e. right roll, roll
axis off right wing tip)

C. Roll axis off to opposite side of

model as roll command

A. Model flies straight ahead without

yawing

B. Model yaws away from roll

command (i.e. right roll, yaw left)

C. Model yaws towards roll command

(i.e. right roll, yaw right)

A. Differential settings OK
B. Increase differential
C. Decrease differential

10. Dihedral

Method 1: Fly the model on

normal pass and roll into
knife-edge flight; maintain
flight with top rudder (do
this test in both left & right
knife-edge flight)

Method 2: Apply rudder in

level flight

A. Model has no tendency to roll
B. Model rolls in direction of applied

rudder

C. Model rolls in opposite direction in

both tests

A. Dihedral OK
B1. Reduce dihedral
B2. Use mixer to produce

aileron opposing rudder
travel (start with 10%)

C1. Increase dihedral
C2. Mix ailerons with rudder

direction 10%

11. Elevator

alignment
(for models
with
independent
elevator
halves)

Fly the model as in Test 6
and pull up into an inside loop.
Roll it inverted and repeat the
above by pushing it up into
an outside loop.

A. No rolling tendency when elevator

applied

B. Model rolls in same direction in both

tests - halves misaligned.

C. Model rolls opposite directions in

both tests. One elevator half has
more throw than the other (model
rolls to side with most throw).

A. Elevators in correct

alignment

B. Either raise one half, or

lower the other

C. Reduce throw on one side,

or increase throw on the
other.

12. Pitching in

knife-edge
flight

Fly the model as in Test 10

*Trim tab is 3/16" x 3/4" x 4" trailing edge stock, placed just in front of aileron on bottom, pointed end forward.

A. There is no pitch up or down
B. The nose pitches up (the model

climbs laterally)

C. Nose pitches down (model dives

laterally)

A. No adjustment needed
B. Alternate cures:

1) move CG aft;
2) increase incidence;
3) droop ailerons;
4) mix down elevator with

rudder

C. Reverse 'B' above