FUTABA 8UHPS Instruction Manual page 62

The pitch curve is defined by a 5-point curve so that you may set the best pitch motion
relative to throttle stick movement. Each point on the curve can be adjusted over a 0% to
100% range.
The T8U system contains five pitch curves: normal (NORM), idle-up 1 (IDL1), idle-up 2
(IDL2), hold (HOLD), and inverted (INVR). The basic normal pitch curve is the only one
displayed in the Basic Menu, but all of the pitch curves can be viewed in the Advance menu.
The Normal curve is exactly the same in both the Advance and Basic Menus.
Use the idle-up switch (switch G) to move between Normal, idle-up 1, and idle-up 2.
(The PI-CURV functions for IDL1 and IDL2 curves will not operate until the OFST-1 and
OFST-2 functions are activated.) Switching to the hold (HOLD) function is performed with
switch E. Switching to the inverted (INVR) function is performed with switch H. Note that
w henever the hold switch is turned on, it has priority regardless of the idle-up switch position.
The normal (NORM) pitch curve function produces the basic pitch curve for flight near
hover. It is set up to provide up and down control at a constant engine speed along with the
n ormal throttle curve.
The HI-side pitch curve limits the maximum rotor pitch so that a large load is not applied
to the engine. The LO-side pitch curve produces a curve with a minimum pitch of -4°.
Idle-up 1 is used for 540° stall turns, looping, and rolling stall turns, while idle-up 2 is used
f or rolls.
The throttle hold curve is used when performing autorotations, and should provide pitch
from -4° to +12°. To get this pitch range, set the HI and LO rates to +100% and -100%
respectively.
Examples of these four curves are shown below:
NORM Pitch Curve Example
70%
55%
30%
17%
1 2 3 4
Curve Point
LOW ← throttle stick → HI
IDL2 Pitch Curve Example
58%
43%
27%
10%
1 2 3 4
Curve Point
LOW ← throttle stick → HI
IDL1 Pitch Curve Example
100%
90%
75%
50%
25%
7%
0%
1
5
LOW ← throttle stick → HI
HOLD Pitch Curve Example
100%
75%
70%
50%
25%
0%
1
5
LOW ← throttle stick → HI
100%
75%
68%
57%
50%
40%
25%
28%
0%
2 3 4 5
Curve Point
100%
75%
50%
25%
0%
2 3 4 5
Curve Point
59