Avionics Raceway

Hey guys,
I'm working on a new avionics interface design. For ease of integration and volume constraints I'm going to run wires on the outside of the airframe in a "raceway." While it is possible to just epoxy the wires down, I don't find that a particularly elegant solution. My plan right now is to use 1/2 in PVC pipe cut lengthwise and contoured to match the airframe. The end caps would be 3d printed. Before going to all that trouble though I though I'd ask here to see if anyone has any experience with raceways on HPRs. Baring that, any thoughts on the PVC idea?

Bonus pics:
Avionics bay cable management

In there is a Telemetrum, StratoLoggerCF, XBee Pro900, BeagleBone, custom BeagleBone cape with sensors, and Poloulu Motor Driver. Batteries are 3, 2 cell 1 amp hour lipos, 1, 2 cell 1800 mAh lipo, and 1, 1 cell 900 mAh lipo. Hypothetically this system will control a parafoil for a guided recovery.

Can you post some more pictures. I would like to see a closer pic and one of the back.

I have no idea what you are trying to send down the cables, but a raceway on a hobby rocket is inelegant, not aerodynamic and heavy.

1.) The basic practical hobby solution is to use flat ribbon cable. Run a strip of 0.002"-0.005" thick 3M VHB transfer tape down the airframe, press the ribbon cable over it, and cover the ribbon cable with a 0.003" thick polyester electrical or masking tape. Minimum thickness, minimum drag and no end caps required. Total thickness is 0.005" to 0.008" thick + the thickness of the standard ribbon cable.

2.) The high tech professional method is to make a Kapton(R) or polyester multi-conductor flex circuit cable and use the VHB tape to fasten it to the airframe. Total thickness is ~0.010" for the flex circuit + ~0.002"to 0.005" thick for the VHB. You can have the flex circuit fabricated with the 3M VHB adhesive preinstalled on the flex circuit.

https://www.mcmaster.com/#3m-transfer-tape/=1260gaz VHB transfer tape

Bob

cwbullet said:

Can you post some more pictures. I would like to see a closer pic and one of the back.

Click to expand...

Ask and ye shall receive.



These pictures were taken ~7:50 a.m with the avionics bay having not existed 12 hours prior. I can't really do closer pics. The avionics bay coupler didn't fare so well during the recovery failure. I have some video from integration if you would be interested in that. Let me know and I'll upload it.

The raised platform on the back lines up with the exterior hatch. Three rotary switches control the three altimeters. The USB and Ethernet ports allow for reprogramming and recharging on the fly. In the picture of the battery side of the sled the Lipos aren't mounted yet. The two 1Ah lipos go on the upper left corner. There were two 9v batteries on this sled. Those will be replaced. This avionics bay is getting rebuilt very similarly.

For video of the awesome launch on an M3400 see here (and a less awesome view of the unintentional tumble recovery):

[video=youtube;js3q9aF-rfo]https://www.youtube.com/watch?v=js3q9aF-rfo[/video]

bobkrech said:

I have no idea what you are trying to send down the cables, but a raceway on a hobby rocket is inelegant, not aerodynamic and heavy.

Click to expand...

bobkrech said:

1.) The basic practical hobby solution is to use flat ribbon cable. Run a strip of 0.002"-0.005" thick 3M VHB transfer tape down the airframe, press the ribbon cable over it, and cover the ribbon cable with a 0.003" thick polyester electrical or masking tape. Minimum thickness, minimum drag and no end caps required. Total thickness is 0.005" to 0.008" thick + the thickness of the standard ribbon cable.

2.) The high tech professional method is to make a Kapton(R) or polyester multi-conductor flex circuit cable and use the VHB tape to fasten it to the airframe. Total thickness is ~0.010" for the flex circuit + ~0.002"to 0.005" thick for the VHB. You can have the flex circuit fabricated with the 3M VHB adhesive preinstalled on the flex circuit.

https://www.mcmaster.com/#3m-transfer-tape/=1260gaz VHB transfer tape

[FONT=Verdana, Arial, Tahoma, Calibri, Geneva, sans-serif]Bob

Click to expand...

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[FONT=Verdana, Arial, Tahoma, Calibri, Geneva, sans-serif]Thanks Bob, that sounds like a great solution. Ribbon cable is absolutely an option. The raceway size and mass is not super consequential to behemoth of a rocket we have concocted, but it does seem slightly ham handed to have a channel on the side of the rocket.[/FONT]