# Tiltrotor VTOL on frame type PLUS

**URL:** <https://discuss.px4.io/t/tiltrotor-vtol-on-frame-type-plus/33111>\
**Category:** PX4 Autopilot\
**Created:** [July 6, 2023, 3:17pm UTC](https://discuss.px4.io/t/tiltrotor-vtol-on-frame-type-plus/33111 "2023-07-06T15:17:21Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![Muiota\_Betarho](https://discuss.px4.io/user_avatar/discuss.px4.io/muiota_betarho/32/13701_2.png) [@Muiota\_Betarho](https://discuss.px4.io/u/Muiota_Betarho)\
**Post date:** [July 6, 2023, 3:17pm UTC](https://discuss.px4.io/t/tiltrotor-vtol-on-frame-type-plus/33111/1 "2023-07-06T15:17:21Z")

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Hello!  
I trying build a new type of frame tiltrotor VTOL.  
Two motors rotate with one servo.  
Tiltrotor VTOL E-flite is similar to my solution but has two independent servos and three motors.  
In my prototype one servo and four motors.  
I tried Generic QUAD aurframe in multirotor mode, takeoff and landing were successful.  
What is the best sequence of flight modes for going to the fixed wing mode?  
What airframe type of frame is better for prototype for tilt rolors and aileron control?  
Where can find info about modifying the firmware for my frame type?  
Big thanks!

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**Author:** ![Igor\_Misic](https://discuss.px4.io/user_avatar/discuss.px4.io/igor_misic/32/13536_2.png) [@Igor\_Misic](https://discuss.px4.io/u/Igor_Misic)\
**Post date:** [July 8, 2023, 9:58am UTC](https://discuss.px4.io/t/tiltrotor-vtol-on-frame-type-plus/33111/2 "2023-07-08T09:58:24Z")

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Don’t know much about other questions but I can help with this

> Where can find info about modifying the firmware for my frame type?

you should look for a new PX4 future called **dynamic control allocation**. If you are using PX4 1.14 it is enabled by default. If you are using 1.13 then you will need to enable it with the param `SYS_CTRL_ALLOC`  
vehicle setup —\> parameters —\> search SYS\_CTRL\_ALLOC

This will give you freedom in configuring your vehicle. Learn more about this here:  
[https://docs.px4.io/main/en/config/actuators.html](https://docs.px4.io/main/en/config/actuators.html)

> **[Igor Misic is PX4 Autopilot Contributor](https://www.buymeacoffee.com/igormisic)**
>
> If you find this useful, you can show your appreciation by buying him a coffee. If you need more personalized help, you can consider hiring me as a freelancer.

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<div class="post-metadata">

**Author:** ![Muiota\_Betarho](https://discuss.px4.io/user_avatar/discuss.px4.io/muiota_betarho/32/13701_2.png) [@Muiota\_Betarho](https://discuss.px4.io/u/Muiota_Betarho)\
**Post date:** [July 10, 2023, 12:06pm UTC](https://discuss.px4.io/t/tiltrotor-vtol-on-frame-type-plus/33111/3 "2023-07-10T12:06:00Z")

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> [@Igor\_Misic](#):
>
> SYS\_CTRL\_ALLOC

Thank you for the quick answer!

Yeah! I have builded the latest firmware from github.  
Now I see the following settings.

 ![actuator_settings](https://discuss.px4.io/uploads/default/original/2X/0/070aeb4ccfa40f1498ad19b90bcfe045d1cbb948.png)  
Currently I’m trying to figure out in what measure unit of settings for surfaces and servos. (slew rates scales and etc)

I’ll share my progress in this topic.