FUTABA 8UHPS Instruction Manual page 50

You can use Throttle Curve menus to program a five-point curve so that the
engine speed responds the way you like relative to movement of the throttle stick.
You can set each of the five points over a 0% to 100% range.
There are three throttle curves: normal (NORM), idle-up 1 (IDL1), and idle-up 2
(IDL2). Only the basic normal throttle curve is displayed in the Basic Menu, but all
the curves may be programmed in the Advance Menu. For your convenience, the
normal curve can be programmed in either the Basic or Advance Menu, and it is
automatically updated in both places. Switch G is programmed so that you may
change between the normal (NORM), idle-up 1 (IDL1), and idle-up 2 (IDL2) curves.
The normal throttle curve (TH-CRV NORM) function is used to produce the basic
throttle curve for flight near hover. It is used along with the normal pitch curve (PI-
CRV NORM) so that the helicopter flies with constant rotor RPM. The normal
throttle curve function is ON at startup.
The idle-up curves should be programmed so that the engine maintains constant RPM
even when the pitch is reduced during flight. The curves should be matched to loops,
rolls, and other maneuvers, and are divided into idle-up curve 1 and idle-up curve 2.
The TH-CURV functions for IDL1 and IDL2 curves will not operate until the OFST-1
and OFST-2 functions are activated.
Throttle Curve IDL1 Example
60%
55%
1 2
Curve Point
LOW
Throttle Curve Norm Example
30%
0%
1 2
Curve Point
LOW throttle stick
100
75%
75%
50%
50%
25%
0%
3 4 5
throttle stick HI
100
75%
70%
50%
50%
25%
0%
3 4 5
HI
Throttle Curve IDL2 Example
71%
68%
1 2
Curve Point
LOW throttle stick
47
100
75%
75%
68%
50%
25%
0%
3 4 5
HI