Rescue Hexacopter Project

 

Design - Bottom Plate

In order to complete the body we need to create several structures. The first thing we need is a structure to support the arms. We will need the axis of the arms to align with the edge of the Bottom Plate in order minimize the size of the craft. To do this we designed arm supports which have cleats or tabs which set into the bottom plate and top plate of the body. The tabs or cleats will epoxied and clamped by 4mm screws during final assembly.

Arm Supports

The supports should be at least 22 mm (the diameter of the arm tube) with 4 mm ring for strength. This would give us a height for the support of 30 mm. The center of the support should align with the edge of the bottom plate with a cleat which is 1/2 from edge. In addition, we will need two slots cut into the supports to accomodate a front and rear support which will provide the anchor for the arms. Our design is as follows:

Arm Support

Arm Support

We will need a total of 24 arm supports or a total of 4 per arm.

Arm Support Brace

The arm support brace is designed to lock into the Arm Support and the Top and Bottom plates to provide a secure anchor point for the arms. Like the arm supports, it is 30 mm tall and it is 3 inches long where in meets the arm support. The brace will have two 4 mm holes for the screws which will secure the arms. We will need a total of twelve of these, two per side. The arm support brace looks like this:

Arm Support Brace

Arm Support Brace

The remaining part for Arm Support Assembly is simply a 30 mm by 3 inches plate with a two hexagons cut out where the retaining bolts go through. This plate will be epoxied to the back side of both arm support braces, and a hex nut will epoxied in cut out area. The Arm Support Lock plate looks like this without the hex nut:

Arm support lock plate

Arm Support Lock Plate

The Arm Support Assemby is constructed with 4 Arm Supports, two braces, and two lock plates. The final assembly looks like this:

Arm Support Assembly

Arm Suppport Assembly

Six of the Arm Support Assemblies are needed for the project. They are secured to the bottom body plate by inserting the tabs or cleats into corresponding slots in the bottom body plate as shown:

Bottom Plate with Arm Assemblies

Bottom Plate with attached Arm Support Assemblies

Socket Plug Assembly

The socket plug assembly provides the electrical connection to the motors. The arm slides through the Arm Support Assembly and plugs into the Socket Plug Assembly. To fabricate the needed Socket Support we simply took an Arm Support and placed two 4 mm holes diagonally .25 inches from the top and sides of the support. We will need 18 of these supports, 3 per side.

Socket Support

Socket Support

To ensure that the socket supports are aligned and locked together, we designed a socket brace. The socket brace is inserted into the slots in the Socket Support during final assembly. We will need twelve socket braces, two per side.

Socket Brace

Socket Brace

The Socket Back plate is used to anchor the back of the socket. It needs to have holes for the wires to pass through as well as bolt holes to secure the assembly. We will need six Socket Back Plates, one for each side.

Socket Back Plate

Socket Back Plate

To assemble the Socket Assembly, we need a 28 mm section of a 22 mm carbon fiber tube. Into the section we epoxy an female ESC to Motor connector.

Socket

This socket will be epoxied to the Socket Back Plate once the wires are soldered and run. The final Socket Assembly is shown below.

Socket Assembly

Six Socket assemblies will be needed and they will be inserted in the slots on the bottom plate as shown:

Bottom plate with socket installed

In addition, we will attach six 30 mm aluminum standoffs to the inside using 4 x 10 mm screws inserted from the bottom. The standoffs will be cut from 3' aluminum standoffs by our Metal Fabrication class.

Bottom plate with standoffs

Now that all the structures are in place, we will cap the body with a another hexagonal plate which we call the Top Body Plate. It has the same size and cut-outs as the Bottom Plate with several modifications. First, a 4 in wide hexagon is cut out of the center to allow access to the interior. Also a hole is placed on the center of each side of the Top Plate 1/2 in from the edge for mounting a angle bracket to attach the prop shield. On every other side of the hexagon is placed two slots for battery tie-downs. Further modifications are expected before we finally finish the design.

Top Plate

The top plate will be secured to the bottom plate by eighteen 4 mm x 40 mm Screws and eighteen 4 mm hex nuts. Two 4 mm x 10 mm screws will be needed to attach the top plate to the aluminum standoffs at the front and rear of the body. The remaining four standoffs will be secured with 50 mm screws. These 50 mm screws will go through the standoffs and extend beyond the bottom plate and allow us to attach standoffs for the landing gear.

Body

Top Plate mounted on Assembly

Inserting the Arms into the sockets, we get the following:

Body with Attached Arms

 

Body Component Drawings
Part/Assembly PDF STEP
4 x 40 mm Screw 4 x 40 mm Screw.pdf 4 x 40 mm Screw.stp
28 x 22 mm CF Tube 28 x 22 mm CF Tube.pdf 28 x 22 mm CF Tube.stp
30 mm Standoff 30 mm Standoff.pdf 30 mm Standoff.stp
Arm Lock Plate Arm Lock Plate.pdf Arm Lock Plate.stp
Arm Support Arm Support.pdf Arm Support.stp
Arm Support Assembly Arm Support Assembly.pdf Arm Support Assembly.stp
Arm Support Brace Arm Support Brace.pdf Arm Support Brace.stp
Socket Assembly Socket Assembly.pdf Socket Assembly.stp
Socket Back Plate Socket Back Plate.pdf Socket Back Plate.stp
Socket Brace Socket Brace.pdf Socket Brace.stp
Socket Support Socket Support.pdf Socket Support.stp
Top Body Plate Top Body Plate.pdf Top Body Plate.stp

 

 

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