Electronics Bay Design - Putting It All Together

This design guide is not an end all work and will always be a "work in progress".  There are so many ways to design and build anything involving electronic, that at times, it can be so daunting that you don't know where to start.  I set out to make a complete series of parts available to allow you to design the bay the way you want to, but that can make things more difficult in trying to find the right parts for your project.

What you will find here are the parts list for some of the common types of bays - pictures will be coming.  Some of types will fit what you want to do and others won't.  Hopefully it will spark an idea and make your next electronics bay better than what has been done before.  Comments, ideas, and project photos are always welcome.

A few notes first

  • Altimeter sleds come in three different lengths - small (85mm), medium (115mm) and large 150mm).   Custom sleds can be designed for you up to 8" in length and 4.25" in depth.
  • Every parts that "consumes" space in a bay will have a value listed in the specifications telling you how much room it takes.  The overall length is not always important except for sleds because I made them the "standard" for measurement (a sled always "consumes" its length in a bay).  The tabs on the parts the sleds mount to "consume" nothing.
  • CT is used for coupler tube and refers to standard Blue Tube dimensions or equivalent product.
  • BT is used for body tube and refers to standard Blue Tube dimensions or equivalent product.
  • Float will refer to parts that can be located inside of a BT, but are usually located near the ends of a bay.
  • Cap will refer to all parts that have a outer rim to keep them from sliding inside a tube.  There is also a further distinction for an End Cap.  An End Cap mimics a standard aft motor closure, so a motor retainer can be used to hold a bay in its body tube (BT).

Designs for All-in-One SMT Designs Tubular Bays

Dual Deploy Small Bay Minimum Diameter

This bay is designed to be as short as possible for the sled you choose and it fits in a 54mm minimum diameter rocket.  It has a wired-in sled, battery, and arming switch.  The battery is accessed by removing the four sled screws and lifting the sled up to install or replace the battery.  The deploy bulkheads float, so they are actually expoxied in place during assembly.  Sleds can be changed out with re-wiring.  The deploy mounting rings incorporate machine screw nuts that can be used to hold the bay in place along with the upper and lower airframe tubes for the drogue and main parachutes.

Parts list

Quantity Part # Description
2 BHC2P-00500 54mm CT 2 Post Deploy Float Bulkhead Kit
2 DSC-00525   54mm CT Deploy Mounting Ring Kit
1 SWCR-00520 54mm CT Radial Switch End Plate Kit
1 BT9V-00512 54mm CT 9 Volt Battery Tray Kit
1 EPC-00523 54mm CT End Plate Kit
1 Sled Part Number Select Sled from list or Contact Me for support for your altimeter
1   Required length of Blue Tube CT

Small Bay Parts Lineup 

Dual Deploy Medium/Long Bay Minimum Diameter

This bay is designed to use the sled and bay connectors for easy field replacement or upgrade of an altimeter.  The bay requires either a medium or long sled to be used.  It can be designed for minimum diameter as well as internal mounting in a larger airframe (98mm and above for 54mm electronics bays).  The bay is totally reconfigurable and has a removeable sled, and includes a battery tray and arming switch.  The battery is accessed by removing the four sled screwsa and unplugging the sled to install or replace the battery.  The deploy mounting rings incorporate machine screw nuts that can be used to hold the bay in place along with the upper and lower airframe tubes for the drogue and main parachutes.

Parts list for minimum diameter

Quantity Part # Description
2 CC2P-00503 54mm CT 2 Post Deploy Cap Kit
2 DSC-00525 54mm CT Deploy Mounting Ring Kit
1 SWCR-00520 54mm CT Radial Switch End Plate Kit
1 BT9V-00512 54mm CT 9 Volt Battery Tray Kit
1 EPCC-00517 54mm CT End Plate Connector Kit
1 Sled Part Number Select a Medium or Long Sled from list or Contact Me for support for your altimeter
1 SWL-00100 Sled Connector Wiring Kit
1   Required length of Blue Tube CT

Medium Bay Parts Lineup

Dual Deploy Internal Mount for Larger Airframes

This bay is designed to be installed in an internal BT and help in place by one or two motor retainers.  The parts list will detail the use of two motor retainers.  If you choose to use one retainer, then it is recommended that you epoxy a small length of coupler tubing (1") at the end of the BT bay tube to help seal the bay and also reduce flight stress on the bay by distributing the load to both ends.  If you are doing a high acceleration flight (over 50 g's), it is highly recommended to use two motor retainers.

Parts list for 75mm and larger airframes

Quantity Part # Description
1 DC2P-00501 54mm 2 Post Deploy End Cap Kit
1 CC2P-00503 54mm CT 2 Post Deploy Cap Kit
2 DSC-00525 54mm CT Deploy Mounting Ring Kit
1 SWCR-00520 54mm CT Radial Switch End Plate Kit
1 BT9V-00512 54mm CT 9 Volt Battery Tray Kit
1 EPCC-00517 54mm CT End Plate Connector Kit
1 Sled Part Number Select a Medium or Long Sled from list or Contact Me for support for your altimeter
1 SWL-00100 Sled Connector Wiring Kit
1 ECBS-00526 54mm End Cap Bay Stop
1   Required length of Blue Tube CT for bay
1   Required length of Blue Tube BT for CT bay to be installed in
2   Threaded Motor Retainers
2   Airframe BT to bay BT centering rings

 

Redundant Dual Deploy Medium/Long Bay for Larger Airframe

Redundant dual deploy is usually relegated to those individuals pursuing L3 certifications and others pushing the envelope with newton fever to even larger motors, clusters, airstarts, and mutliple stages (it is all great!).  I also think due to lower costs, there is a growing number of people doing redundant designs as a standard thing.

Parts list for 98mm and larger airframes

Quantity Part # Description
1 DC2P-00501 54mm 2 Post Deploy End Cap Kit
1 CC2P-00503 54mm CT 2 Post Deploy Cap Kit
2 DSC-00525 54mm CT Deploy Mounting Ring Kit
2 SWCR-00520 54mm CT Radial Switch End Plate Kit
2 BT9V-00512 54mm CT 9 Volt Battery Tray Kit
2 EPCC-00517 54mm CT End Plate Connector Kit
2 Sled Part Number Select Medium and/or Long Sleds from list or Contact Me for support for your altimeter
2 SWL-00100 Sled Connector Wiring Kit
1 ECBS-00526 54mm End Cap Bay Stop
1   Required length of Blue Tube CT for bay
1   Required length of Blue Tube BT for CT bay to be installed in
2   Threaded Motor Retainers
4   Airframe BT to bay BT centering rings

 

Redundant Dual Deploy Bay with Medium Sleds

 Redundant Dual Deploy Bay with Medium Sleds

Connectors Assemblies Added on Redundant Dual Deploy Bay

Payload/Nosecone Bay for Larger Airframes

This bay is designed to be end mounted only and inserted into a BT usually located in the nosecone.  It has an axial switch which is accessible from the bottom of the bay, so you can "arm" the bay during prep of the rocket for launch (note: if it includes any type of pyro charges, it should never be armed unless you are at the launch pad).  Until SMT Deisgns releases a payload type of product, the list here details what you need to tracker type bay for your own purpose.  I would be happy to discuss custom sled designs that you would need.

Parts List

Quantity Part # Description
1 SWCA-00514 54mm Axial Switch End Cap Kit
1 BHCCA-00529 54mm CT SMA Connector Cap
1 DSC-00525 54mm CT Deploy Mounting Ring Kit
1 CLCSS-00515 54mm CT Sled-Sled Coupler
1 BT2SLI-00513 54mm CT 2S 1200mAh LiPo Battery Tray Kit
1 SLDEVP-03147 Power Supply/Dev Board Sled Kit
1 SLGPSDEV-03148 GPS/Dev Board Sled Kit
1 DPCB-00139 Dev Boards Kit
1 SMACC-00135 SMA Connector Clip
1   User supplied 2S LiPo battery, GPS module, processor, Pololu Regulator, wires, and antenna

 Rocket Tracker Bay

Traditional Bays Using SMT Designs General Components

Traditional bays come in many forms.  Some companies have bay kits you can  buy or that are included with rockets they sell.  Usually, they all include a sled of some kind.  The products I designed can be mounted on sleds and end plates to provide external arming, insulated feedthrus for deploy charges, and reliable electrical connections inside the bay.  The two varieties I have created here detail how I would design a electronics bay if I had one of these bays.

Dual Deploy Adapted Bay

The adapted bay came from an idea I had while discussing rocketry in general with a dear friend of mine that I have known since I started in rockets back in 92.  The premise is very simple really.  I created adapter brackets that can be used to hold a tubular electronics bay assembly in place on a sled.  The bay could be taken out, SMT Designs deploy parts attached to the ends and then flown in another rocket as a complete assembly if desired.  Because I have already covered a SMT Designs version for dual deploy, I decided that the adapted bay will only has a sled & sled connector, along with a connector end plate.  The remaining parts I have in the list will be used for all the other connections that have to be done in order to complete the project.

Parts list

Quantity Part # Description
1 EPWC-00518 54mm CT Wiring Connector End Plate Kit
1 CC2P-00503 54mm CT End Plate Kit
2 DSC-00525 54mm CT Deploy Mounting Ring Kit
1 Sled Part Number Select Medium and/or Long Sled from list or Contact Me for support for your altimeter
1 SWL-00100 Sled Connector Wiring Kit
1 SAC-00110 Bay Adapter for 54mm Coupler Tube Kit
1   Required length of Blue Tube CT for bay

 

Dual Deploy Bay

Parts list

Quantity Part # Description
2 DF2P-00104 2 Post Feedthru Kit
3 CB4EM-00107 4 Terminal Tab Mount Connector Block Kit
3 CM4T-00108 4 Terminal Mating Connector Kit
1 BH9V-00112 Bay 9 Volt Battery Holder Kit
1 SWBY-00109 Bay Switch Kit
1 WR10C-00138 Ten Color Wire Kit
1   hardware to mount various parts (dependent on sled)

 

Dual Deploy Bay with SMT Designs Sled

Parts list

Quantity Part # Description
2 DF2P-00104 2 Post Feedthru Kit
3 CB4EM-00107 4 Terminal Tab Mount Connector Block Kit
3 CM4T-00108 4 Terminal Mating Connector Kit
1 BH9V-00112 Bay 9 Volt Battery Holder Kit
1 SWBY-00109 Bay Switch Kit
1 SBR-00113 Sled Brackets
1 Sled Part Number Select Medium and/or Long Sled from list or Contact Me for support for your altimeter
1 WR10C-00138 Ten Color Wire Kit
1   hardware to mount various parts (dependent on sled)