# SITL for a new VTOL airframe

**URL:** <https://discuss.px4.io/t/sitl-for-a-new-vtol-airframe/4703>\
**Category:** PX4 Autopilot\
**Created:** [October 21, 2017, 10:54am UTC](https://discuss.px4.io/t/sitl-for-a-new-vtol-airframe/4703 "2017-10-21T10:54:45Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![Vijeth\_Hebbar](https://discuss.px4.io/letter_avatar_proxy/v4/letter/v/cab0a1/32.png) [@Vijeth\_Hebbar](https://discuss.px4.io/u/Vijeth_Hebbar)\
**Post date:** [October 21, 2017, 10:54am UTC](https://discuss.px4.io/t/sitl-for-a-new-vtol-airframe/4703/1 "2017-10-21T10:54:45Z")

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I have a created a new air frame which has a + VTOL configuration. The Gazebo model for the same is also something I have created as in the picture below.

 ![](https://discuss.px4.io/uploads/default/original/2X/7/74c95a5fedb5a940ce067fed67dd46a89490ea5a.jpg)

To simplify my job I decided to replace the model’s .sdf and .config file in the default tail sitter model (which has VTOL X configuration) that comes with the Firmware. I also changed the default tailsitters mixer in the _posix-config/SITL/init/ekf2/tailsitter_ from the VTOL X to VTOL + configuration. I am a beginner to using PX4 and this is my first project using it. How do I proceed further?

If I give a takeoff command on gazebo the drone pitches over falls upside down. The log for the same is here [Gazebo Log File](https://drive.google.com/open?id=0B3lgARalizUnZjdzUUdpNnQxZ2s)

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**Author:** ![dagar](https://discuss.px4.io/user_avatar/discuss.px4.io/dagar/32/22_2.png) [@dagar](https://discuss.px4.io/u/dagar)\
**Post date:** [October 22, 2017, 3:07pm UTC](https://discuss.px4.io/t/sitl-for-a-new-vtol-airframe/4703/2 "2017-10-22T15:07:01Z")

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Replacing tailsitter can work, but all you really need to do is duplicate all those pieces, but call them something else.

Then to build and run everything together `make posix_sitl_default gazebo_tailsitter`.