Fixed Wing Autolaunch
Fixed Wing Autolaunch, aka launch mode, allows the pilot to have assistance in launching their airplane. This can be particularly useful if you're a new pilot, have a difficult model to launch, or have a large model.
By default, autolaunch will not work. You need to tell INAV that you want to use it. There are two ways to do this. You can use a switched mode, or you can have it permanently enabled. Which you choose it personal preference. The switch gives you more control. Having it permanently enabled means it will work all the time. But if you don't want to use it, you must remember to move the pitch or roll stick to deactivated it.
To use a switch. You will need to set a switch to a channel on your transmitter. Then in the Modes page in INAV Configurator. Set NAV LAUNCH mode to be active when the switch is in the chosen position. If you don't see the NAV LAUNCH mode. You may have the permanent method enabled.
To have Autolaunch permanently enabled. You need to activate the Permanently enabled Launch Mode for Fixed Wing feature on the Configuration page. If this is enabled, the NAV LAUNCH mode will not be found on the Modes page.
The basic settings for Autolaunch can be found on the Advanced Tuning page in INAV Configurator. These settings should be all that you need to change to get launch mode working well for your model.
Tip
The Autolaunch settings on the Advanced Tuning page are ordered in the way they happen during the launch. So they start with idle throttle (the first part of launch mode to activate, if set) to the end transition time (the end of the launch).
We will look at these setting briefly. But there are videos explaining the settings, including this one.
The Idle Throttle setting allows you to let the motor spin at the desired throttle level before you throw the airplane. This can be useful if:
- you have a large or heavy aircraft that will benefit from some additional push
- your plane suffers from torque roll
- you would like a visual indicator that the aircraft is ready to launch
The amount of Idle Throttle you need depends on your goal. If you only want a visual indicator, a low value like 1000uS (10%) will work for you. However, if you want to have some launch assistance or to combat torque roll. You will need to estimate and adjust this value until it works well for your aircraft. A good starting point may be half the launch throttle, which we will cover later. If you don't want to use Idle Throttle. Set the value to 1000uS (0%)
Note
If you see a red box around the Idle Throttle. It is because you have specified an Idle Throttle Delay but do not have an Idle Throttle set.
Idle Throttle Delay adds a delay between raising the throttle and the Idle Throttle* starting. This is extremely useful if you need to do something like put your transmitter down and pick up your airplane. Or just to get yourself prepared. If you do not want to use an Idle Throttle Delay. Set this to 0.
The Max Throw Angle setting is the maximum angle that the aircraft can be at to allow the launch to be detected. The default of 45 degrees should be plenty for most launches. Please don't be tempted to set this to a stupid angle like 180 degrees. Even a double-handed overhead launch should only need a maximum of 60 degrees. Any higher than this and the aircraft will likely just stall. There are very few exceptions, where vertical launches are desired. Such as high powered FunJet. Which will have a high power to weight ratio.
Motor Delay is the time between the launch being detected and the motor starting to spin up to Launch Throttle. This setting is pretty important for safety. If you have a tractor plane. This setting can be low safely.
Caution
If the motor speeds up too quickly and you have a pusher plane. You risk a prop strike to your hand. So please be carful when adjusting this.
The Minimum Launch Time setting dictates a time period where the sticks on your transmitter will not respond. This is particularly useful if you have to pick up your transmitter or it's hanging on a neck strap. Setting this to 2 seconds can stop the launch being aborted unintentionally, because you have bumped a stick on your transmitter.
This setting usually doesn't need to be changed. But it can be useful for reducing torque roll or taking stress off of folding props. The Motor Spinup Time is the time taken to go from the starting throttle (0% or Idle Throttle) to Launch Throttle. Lowering this setting is not recommended. But if you have a folding or large prop you could increase it. You could also try increasing this to help avoid torque roll.
Launch Throttle is the main throttle level for the launch. This should be set based on the powertrain and weight of your aircraft. In this video, you can see a physical method for calculating the Launch Throttle. There is also a tool for estimating the launch throttle.
Is the base attitude of the model for the climb. The Climb Angle should be set for the model. Some require a flatter launch to get speed up. Whereas others could have a steeper climb. Your flying environment may also contribute to the Climb Angle.
Note
Fixed Wing Level Trim will be added to the Climb Angle. So a Climb Angle of 20 degrees and a Fixed Wing Level Trim of 5 degrees, would result in a commanded pitch of 25 degrees.
The Launch Timeout is the maximum time that the launch climb phase will take. Once this timeout has been exceeded. The launch will progress to the end transition.
Is the Maximum Altitude that the airplane will climb to. Once this altitude is reached. The launch will progress to the end transition.
Is the time that the final launch phase will take. The End Transition Time makes for a smooth transition from the launch angle and throttle to level flight and the current or cruise throttle.