From d149150a452bc395ed3faa6b0cbdbcf58e97c08b Mon Sep 17 00:00:00 2001
From: George Zogopoulos <tailwhipx4@gmail.com>
Date: Tue, 8 Oct 2024 20:38:08 +0200
Subject: [PATCH] Plane: Added parameter TKOFF_THR_IDLE

---
 ArduPlane/Parameters.cpp | 9 +++++++++
 ArduPlane/Parameters.h   | 1 +
 ArduPlane/servos.cpp     | 5 +++++
 3 files changed, 15 insertions(+)

diff --git a/ArduPlane/Parameters.cpp b/ArduPlane/Parameters.cpp
index d643d8b013..b2db9099f8 100644
--- a/ArduPlane/Parameters.cpp
+++ b/ArduPlane/Parameters.cpp
@@ -158,6 +158,15 @@ const AP_Param::Info Plane::var_info[] = {
     // @User: Standard
     ASCALAR(takeoff_throttle_min,       "TKOFF_THR_MIN",    0),
 
+    // @Param: TKOFF_THR_IDLE
+    // @DisplayName: Takeoff idle throttle
+    // @Description: The idle throttle to hold after arming and before a takeoff. Applicable in TAKEOFF and AUTO modes.
+    // @Units: %
+    // @Range: 0 100
+    // @Increment: 1
+    // @User: Standard
+    ASCALAR(takeoff_throttle_idle,       "TKOFF_THR_IDLE",    0),
+
     // @Param: TKOFF_OPTIONS
     // @DisplayName: Takeoff options
     // @Description: This selects the mode of the takeoff in AUTO and TAKEOFF flight modes. 
diff --git a/ArduPlane/Parameters.h b/ArduPlane/Parameters.h
index d29243d1ef..24645b3b88 100644
--- a/ArduPlane/Parameters.h
+++ b/ArduPlane/Parameters.h
@@ -359,6 +359,7 @@ public:
         k_param_autotune_options,
         k_param_takeoff_throttle_min,
         k_param_takeoff_options,
+        k_param_takeoff_throttle_idle,
 
         k_param_pullup = 270,
     };
diff --git a/ArduPlane/servos.cpp b/ArduPlane/servos.cpp
index 49e3e07b46..672631e373 100644
--- a/ArduPlane/servos.cpp
+++ b/ArduPlane/servos.cpp
@@ -619,6 +619,11 @@ void Plane::set_throttle(void)
             // throttle is suppressed (above) to zero in final flare in auto mode, but we allow instead thr_min if user prefers, eg turbines:
             SRV_Channels::set_output_scaled(SRV_Channel::k_throttle, aparm.throttle_min.get());
 
+        } else if ((flight_stage == AP_FixedWing::FlightStage::TAKEOFF)
+                    && (aparm.takeoff_throttle_idle.get() > 0)
+                  ) {
+            // we want to spin at idle throttle before the takeoff conditions are met
+            SRV_Channels::set_output_scaled(SRV_Channel::k_throttle, aparm.takeoff_throttle_idle.get());
         } else {
             // default
             SRV_Channels::set_output_scaled(SRV_Channel::k_throttle, 0.0);