# Landing Gear, PDB, and Rails

## Landing Gear

Each leg consists of two parts. The first is the horizontal part with the T-connector and foam protection. The second is the carbon fiber tube with the connector that can be mounted to the frame.

![Landing gear post and base](https://734487356-files.gitbook.io/~/files/v0/b/gitbook-legacy-files/o/assets%2F-MObZEFR6zG-gnkxXVBb%2F-MSdWAil_YU5XDf7Vtk_%2F-MSdZXCrLEzEA5K0Ejxh%2Flanding_gear.jpg?alt=media\&token=82ad7855-d237-4ca6-b1cb-df8243421c6d)

Begin by loosening the two hex screws on the side of the T-connector with the H2.5 tool. You should now be able to insert the carbon fiber tube. Rotate the inserted tube so that the base legs (with foam) will be aligned properly when the top connector (with four brass threaded inserts) is attached to the bottom frame plate. Tighten both screws on the T-connector to hold the leg in place. Do this for both legs.

{% hint style="warning" %}
Be careful not to overtighten as the plastic T-connector can easily crack with too much force.
{% endhint %}

![Landing gear assembled and ready to mount to bottom plate](https://734487356-files.gitbook.io/~/files/v0/b/gitbook-legacy-files/o/assets%2F-MObZEFR6zG-gnkxXVBb%2F-MSdWAil_YU5XDf7Vtk_%2F-MSdkCSkXmyY8ahZVwBd%2Flanding_gear_and_bottom_plate.jpg?alt=media\&token=49473582-a697-4e59-b350-55c210c5f007)

Next, we will need the bottom plate of the frame. It is one of the two plates with the cutouts as shown above. The bottom plate is the one with the circle-shaped holes in the middle and on the sides. Around the two circle-shaped holes on the sides, there are four small holes for screws. The black M3 socket head cap screws go down these holes and should screw directly into the leg mounts. Nuts are not needed for this part.

{% hint style="info" %}
The T-connector is vulnerable to cracking with hard landings. We have found that adding a zip tie around the connector can help protect it.
{% endhint %}

![Landing gear attached to frame bottom plate](https://734487356-files.gitbook.io/~/files/v0/b/gitbook-legacy-files/o/assets%2F-MObZEFR6zG-gnkxXVBb%2F-MShi-tQ7Uo92Mju7Xi8%2F-MShjZkHdOLWRMC-5ANg%2Fbottom_plate_with_gear.jpg?alt=media\&token=7f53f6ed-702b-43c2-962a-d0c55d45afdb)

## Power Distribution Board (PDB)

Next, we will install the PDB onto the bottom plate. You should have a pre-soldered board included with your kit. This should be located in Box 4 (soft, black case). It already has bullet connectors for your ESCs. It also has a yellow XT60 connector for the FC power module.

{% hint style="info" %}
The PDB is supplied and soldered by a 3rd party. Some participants have noticed a white residue on the backside of the PDB. This may be flux residue leftover from soldering. We recommend cleaning this residue with alcohol first before installing in case this residue inadvertently causes corrosion over time.
{% endhint %}

There should be nylon spacers and nuts included with the PDB. We will use these to mount the PDB on top of the bottom plate.

![Eight nylon spacers and four nuts for PDB mounting](https://734487356-files.gitbook.io/~/files/v0/b/gitbook-legacy-files/o/assets%2F-MObZEFR6zG-gnkxXVBb%2F-MSiHYM2eUKegb0jiMsu%2F-MSiYugDMx1_HZ5CBNrE%2Fpdb_nylon_screws.jpg?alt=media\&token=a4595e0f-d8f9-4c86-8412-dd1e1a0aaa9e)

There are eight holes for screws distributed in a circle around the center of the bottom plate. We will use the "diagonal" holes. These are the ones that will allow the edges of PDB to be parallel with the edges of the bottom plate.

You will install the spacers as shown in the photo below. Place a spacer beneath the bottom plate and another on top. Using your fingers you will be able to screw them together. Do this for all four corners.

![Beneath the bottom plate is a spacer screwed to a spacer on top](https://734487356-files.gitbook.io/~/files/v0/b/gitbook-legacy-files/o/assets%2F-MObZEFR6zG-gnkxXVBb%2F-MSiHYM2eUKegb0jiMsu%2F-MSiiT1OUToIawaQmVBH%2Fpdb_spacer_and_nut.jpg?alt=media\&token=a4cf5578-b4d7-439b-86bc-3191d10c725b)

At this point you can place the PDB down on the spacers so the threads poke through the corner holes. Now use the remaining four nuts to tightly secure the PDB to the top spacers.

{% hint style="warning" %}
Make sure to orient the PDB so that the yellow XT60 connector is facing the rear of the frame. The photo below shows the front of the frame with a small triangle etched in the cutout.
{% endhint %}

You can place the XT60 connector through the rear frame hole. In an upcoming section we'll be connecting the FC power module to the XT60 connector of the PDB.

![PDB mounted to bottom plate. Note the XT60 placed through the rear cutout.](https://734487356-files.gitbook.io/~/files/v0/b/gitbook-legacy-files/o/assets%2F-MObZEFR6zG-gnkxXVBb%2F-MSiHYM2eUKegb0jiMsu%2F-MSik1IHF98EvheI2o0N%2Fpdb_mounted_to_bottom_plate.jpg?alt=media\&token=d411e33e-702b-4e76-b362-809a636e7956)

## Rails

The next step is installing the rails. Other plates and components can easily be attached to them. The rails have a standard of 60 mm spacing with 10 mm carbon fiber tubes, and you can find several 3D printable mounts which fit. These rails will come in handy throughout VRC.

We need the two 10 mm carbon tubes, the two plastic bags with tube mounts and rubber rings, and the small M2.5 screws. There is also a smaller carbon fiber plate included, typically used for camera mounting, that we will put on these rails.

![Components for rail assembly](https://734487356-files.gitbook.io/~/files/v0/b/gitbook-legacy-files/o/assets%2F-MObZEFR6zG-gnkxXVBb%2F-MSmwbcd3I_Zt7OPvFSh%2F-MSnS9120uvlyslSwoHJ%2Frail_parts.jpg?alt=media\&token=9992228a-c96b-42ca-9841-71c55715e48a)

First, push the rubber rings into the tube mounts. This may take some force, but it should be possible without the need for tools. Do this for all eight mounts.

Slide four tube mounts on each carbon tube, such that the screw holes in the tube mounts align with the holes in the bottom plate of the drone.

![Tube mounts aligned with bottom plate and ready to be screwed into place](https://734487356-files.gitbook.io/~/files/v0/b/gitbook-legacy-files/o/assets%2F-MObZEFR6zG-gnkxXVBb%2F-MSnSrUPxl9wJuUjwjVM%2F-MSngYqsF_HmhR3p-KBX%2Frails_bottom_view.jpg?alt=media\&token=bb4a2c65-fc14-4f6d-8268-e8e94db670fb)

We can now easily mount these to the bottom plate using the small M2.5 socket head cap screws. The screws go down from the top and should screw directly into the tube mounts. The extra tube mounts for the small plate should be at the front of the drone.

![Tube mounts screwed into place with supplied hex tool](https://734487356-files.gitbook.io/~/files/v0/b/gitbook-legacy-files/o/assets%2F-MObZEFR6zG-gnkxXVBb%2F-MSnSrUPxl9wJuUjwjVM%2F-MSnga5XY6skXhCJMPSz%2Frails_mounted.jpg?alt=media\&token=18486963-4c5d-42bd-b303-081237f08a26)

Finally, you can mount the small plate to the tube mounts at the front of the frame. You will need the M2.5 phillips-head screws. This plate can be used to mount a camera, companion computer, or any other accessory. More of this will be covered as you progress further into VRC.

![Accessory plate mounted at front of the frame](https://734487356-files.gitbook.io/~/files/v0/b/gitbook-legacy-files/o/assets%2F-MObZEFR6zG-gnkxXVBb%2F-MSnijUSRoqr9FmpK6D2%2F-MSsyqTGiOsrvqFfJczx%2Fcamera_mount.jpg?alt=media\&token=c2614129-aa64-4dfd-bf22-9384d8bec159)

{% hint style="info" %}
It might also be useful to apply a **threadlocking adhesive** (such as Loctite 243) to the screws for the rails and connected plates. In any case make sure to check the screws regularly, especially if you have any payload attached to these rails (such as a camera module).
{% endhint %}
