The Avionics Bay Thread...Post your Photos!

[AllDigital]

Two Eggtimer Protons with a custom PCB to manage remote power, arming/indicators, and integration of two 12V solenoid latches.

 

[CoyoteNumber2]

Two Eggtimer Protons with a custom PCB to manage remote power, arming/indicators, and integration of two 12V solenoid latches.

Is there loss of redundancy by arming through one PCB?

 

[AllDigital]

Is there loss of redundancy by arming through one PCB?

The custom PCB is 100% redundant, so it is like two boards in one. As are the altimeters and batteries. This is for a hypergolic bipropellant rocket with a computer pad controller that interfaces to this board via the rocket umbilical. The pad controller can keep the altimeters 100% powered off while fueling and pressurizing, but then they can be powered up and armed remotely with a positive signal going back to the pad MCU indicating they are armed (can't hear beeps or get wifi in bunkers). The deployment for this rocket is using 12V solenoid latches, so the PCB also has a lot of flyback and protection diodes that allow the altimeters to share a single drogue and main solenoid latch.

 

[CoyoteNumber2]

The custom PCB is 100% redundant, so it is like two boards in one. As are the altimeters and batteries. This is for a hypergolic bipropellant rocket with a computer pad controller that interfaces to this board via the rocket umbilical. The pad controller can keep the altimeters 100% powered off while fueling and pressurizing, but then they can be powered up and armed remotely with a positive signal going back to the pad MCU indicating they are armed (can't hear beeps or get wifi in bunkers). The deployment for this rocket is using 12V solenoid latches, so the PCB also has a lot of flyback and protection diodes that allow the altimeters to share a single drogue and main solenoid latch.

Super cool. Do you have a thread/blog/anything about the rocket and/or pad controller?

I see you're in SoCal - I'm guessing you launch at FAR or RRS?

 

[OzHybrid]

View attachment 474939

Two Eggtimer Protons with a custom PCB to manage remote power, arming/indicators, and integration of two 12V solenoid latches.

If you label your batteries A/B, label your altimeters A/B not 1/2 Consistency goes a long way to success.

 

[bobbyg23]

My newest avbay on the new LOC 7.5" T-LOC. Integrated into the fin assembly.

 

[AllDigital]

Super cool. Do you have a thread/blog/anything about the rocket and/or pad controller?

This is for Genesis. A rocket with a long long history at FAR. If all goes well should launch in September.

https://friendsofamateurrocketry.org/history/

 

[CoyoteNumber2]

My newest avbay on the new LOC 7.5" T-LOC. Integrated into the fin assembly.

I would have thought turbulent airflow around the fins could cause faulty readings in barometric altimeters. Must not be that much of a real problem if that's where LOC decided to put the bay.

 

[DarthMuffin]

My first av-bay. Donut bay for my 4" Wildman Gizmo. It slides over the end of the MMT and sticks up a little farther (see the lip on the inside). Eggtimer Apogee (motor eject as backup, chute on a JLCR), battery, and printed-in charge well on top (untested yet, hope it holds up). Printed in carbon fiber petg. Shock cord eye bolt threads through one of those holes, other hole is a just a holddown (and backup shock cord mount if needed).

 

[bobtheshortstop]

These are all very clever and extravagant designs but can someone post a picture of a VERY basic and simplistic design? I'm getting into dual deploy for the first time and this thread was recommended to me. I'll get to this point of designs some day but it's a far reach as of now.

 

[Troy3003]

These are all very clever and extravagant designs but can someone post a picture of a VERY basic and simplistic design? I'm getting into dual deploy for the first time and this thread was recommended to me. I'll get to this point of designs some day but it's a far reach as of now.

Posts 2-17 have fairly easy to follow setups for dual deploy.

 

[OKTurbo]

Here’s a very basic setup on my Stiletto.
https://www.rocketryforum.com/threads/stiletto-upscale-build-thread.160541/post-2042939

 

[OzHybrid]

Posts 2-17 have fairly easy to follow setups for dual deploy.

If you've got a 10" dia rocket, you can build your AV bay from 4x2 timber, if you've got a 1" min dia rocket you've got a different set of parameters. I've made an AV bay sled from foam core board hot glued to 2 bits of plastic tube with 2 x 3mm threaded rod in between the top and bottom parts.
What rocket is it you want an easy design for? What's the parameters for the design? What tools do you have available to you?

 

[bobbyg23]

These are all very clever and extravagant designs but can someone post a picture of a VERY basic and simplistic design? I'm getting into dual deploy for the first time and this thread was recommended to me. I'll get to this point of designs some day but it's a far reach as of now.

Just finished this last night. Basic as they come

 

[OzHybrid]

Just finished this last night. Basic as they comeView attachment 476526View attachment 476527View attachment 476528View attachment 476529

Lovely use of a piece of 2x1.

 

[Buckeye]

Posted this in another thread, then realized this is a better place for it.

Wildman Mach2 54mm Minimum Diameter with HED. The bulk of my time and effort on this build (by a lot) was spent on the av-bay to hold a SLCF altimeter and Featherweight GPS.

I hacked an Additive Aerospace 54mm sled to hold the altimeter and its battery on one side. Note the two resistors and added terminal blocks for ematches. This is to prevent excessive current through the deployment channels as discussed here.

On the other side, in the battery compartment, is the GPS tracker and its battery. I drilled a hole through the compartment to allow the antenna to poke through. I seriously considered #10-24 nylon threaded rod to hold the bay together (because of the GPS antenna running parallel) and by some rough calculations, deemed it strong enough. However, after a bunch of GPS testing in my neighborhood, I determined that #10-24 aluminum rod wasn't hurting or attenuating the signal, and I felt more at ease with the metal connections.

 

[FlyBy01]

View attachment 475226View attachment 475227

My first av-bay. Donut bay for my 4" Wildman Gizmo. It slides over the end of the MMT and sticks up a little farther (see the lip on the inside). Eggtimer Apogee (motor eject as backup, chute on a JLCR), battery, and printed-in charge well on top (untested yet, hope it holds up). Printed in carbon fiber petg. Shock cord eye bolt threads through one of those holes, other hole is a just a holddown (and backup shock cord mount if needed).

Would you please consider sharing the print file for this AV-bay?

 

[DarthMuffin]

Would you please consider sharing the print file for this AV-bay?

Sure, here is the tinkercad model I made it from. Sharing a link to this rather than the STL so you can more easily edit it/ungroup and change parts, etc. For example your motor mount almost certainly sits a bit higher or lower than mine. Or just export the big piece in the middle as an STL for a copy exactly as I printed it.

If I wasn't clear the two holes on the sides are for a 1/4" eye bolt on one side. Screw it down until just snug, motor case will keep it from loosening. 1/4" threaded rod on the other with a nylon (probably overkill) nut on top. 1/4" holes drilled and washers and nuts expoxied to the bottom of the forward motor mount centering ring. ematch terminals are 3mm bolts, which I happen to have a bunch of in stainless from the 3d printing hobby. Separating those two terminals a little more might be nice on a future version.

After some bench testing I can confirm the charge well works great, and holds just under 1g of BP for me which is perfect. But it's kind of hard to fill and tape off (I imagine really hard with wind in the field) so I'll probably use premade powder charges in something (glove finger, surgical tube, etc) taped to the well. The terminals for the ematch are kind of fiddly, you may need to remove the ebay from the rocket to change out. Which fortunately is really easy, although threading in the eye bolt with shock cord attached is slow.

Be sure to add nut drivers for the 1/4" nut and the ematch terminals to your field kit.

https://www.tinkercad.com/things/3MLifdikpcq

 

[Mugs914]

I'm building a clone of the 2.6" Aerotech HV Arcas and needed to build a sled for it but wanted to do something a little different.

Usually, we build our sleds out of plywood, but I wanted to try to make a lightweight sled built up from very thin wood. This is the one I came up with for the Arcas.

The whole thing is built up from 1/32" basswood, with a couple of 1/16" pieces in higher stress areas. It has a 1/4" carbon tube running down the middle that slides over the all-thread rod that runs through the av-bay. Other than that, and a couple of 1/32" stringers, the sled is hollow. I used a pull-pin switch from Chris at Lab Rat Rocketry (HIGHLY recommended!) that mounts between the top and bottom and is secured by one of the altimeter mounting studs. The battery cradle aft bulkhead rests flush against the rear bulkhead of the av-bay. Unfortunately, I didn't remember to take any pics while I was building the thing, so no shots of the internal structure, but basically, it just a box. It did come out VERY light, but I (drum roll please) forgot to weigh the bare sled before I got everything mounted.

It was at this point that things went a bit sideways...

Being a scale modeler with a predilection for adding un-needed, scale-like details to functional objects, I figured that if it was, basically, a monocoque av-bay sled, well, it needed to look like a monocoque av-bay sled...

A few lines of simulated rivets, some zinc chromate green paint, a bunch of chipped paint and a couple of phony data plates were added to the thing, and it wound up looking like it's been sitting around in an old aircraft warehouse for a while.

Anyway, it was fun to do, and I will certainly be building more of my av-bays this way, though maybe not with all the details and weathering!

Here are some pics...

Battery cradle. Forward is to the right of the pic.

Altimeter side... Got the Stratologger on there now but have room to replace it with an RRC3 for airstarts (This Arcas is intended to fly as an upper stage as well). The slots are for a zip tie to secure the battery.

This shot shows the slot along the side that engages with a carbon tube in the side of the coupler and locates the switch in the proper place.

Rear bulkhead.

Here is how it sits in the coupler tube.




All zipped up!

 

[DeltaVee]

That... is really, really NICE.

 

[BDB]

For those of you who use designs with single threaded rods and eye nuts, like Mugs914 just showed, is there a preferred method for keeping the eye nut from unthreading during descent,

 

[Mugs914]

I usually add a small screw eye to the bulkhead and either safety wire or zip tie the eye nuts to it so that they can't rotate once tightened. I also like to JB weld one of the eye nuts to the threaded rod (kinda makes a long eye bolt) just to make sure the rod can't rotate.

I'll try to get some pics...

 

[DarthMuffin]

Mach 2 avbay I designed and printed. No threaded rod. Dual Eggtimer Quarks with mag switches an altusGPS for tracking (because the metrums are unobtainium). Not the optimal antenna situation but I don't have much for options. Battery for AltusGPS is a 400mah one under it with no switch, will connect as I'm prepping the rocket.

 

[bobbyg23]

Just finished 2 more today.

 

[DragonRocketry]

Couple of mine.

 

[OzHybrid]

I've been working on an E-Bay basic designer program for SCAD.

I'll post it in the 3-D printed section for my rocket chums. If any manufacturers want to create modules of their computers for us to use, I'm happy to incorporate those models for holes and as a removable object to make sure it doesn't hit anything and update the program. This might give them a competitive advantage. Just sayin.....

 

[G_T]

THRP-1, an EX hybrid rocket I flew at Potter. There's a thread in the High Power section on the rocket, and a thread in the Research section on the motor. Tether and CO2, two altimeters, a tracker, and a video camera. 3" rocket.

Gerald

 

[AllDigital]

These are all very clever and extravagant designs but can someone post a picture of a VERY basic and simplistic design? I'm getting into dual deploy for the first time and this thread was recommended to me. I'll get to this point of designs some day but it's a far reach as of now.

This is our simplest avBay sled for a Perfectflite Stratologger CF in a 3" rocket. It is a single 3D print that holds the altimeter and a battery with a simple printed retainer clip. Put two of these in a 3" rocket and you are ready to go. The Thingiverse link below has the source sketch files (free online), so you can easily edit for different battery sizes. This one is based on a 300mah 2S lipo (search F959 battery).

Source files: https://www.thingiverse.com/thing:5348889

 

[Handeman]

I finished the av-bay for my 4" Go Devil. The board with the altimeters and batteries is from a different rocket that had the fin can blown off when I split a case with an EX motor.

This is the Primary altimeter side of the board. The Back Up side is the same. There is one threaded rod on each side so even that is the same. The plywood pieces that hold the batteries have three screws from each side of the board holding them in place. The screw switch and the pull pin switch are in series so the screw switch can turn everything off without needing the pull pin in place while prepping charges. Once everything is prepped, the pull pin is put in and the screw switch is turn on. A little hot glue holds wires in place when needed.


I use terminal strips with solder tabs that project through the bottom on the caps.


In this case, the drogue side is the short side, so the battery terminals are down and all internals are pushed to the terminal end of the battery during thrust.
The main altimeter uses green and white twisted pairs and the back up altimeter uses blue and white. The main charge wires are long enough the whole sled can be pulled out without having to disconnect any wires. They just get looped together when everything is buttoned up.


The hole labeled main is for the screw switch while the pull pin fits through the vent port. There is a single 3/16 fiberglass dowel installed at the joint on the bottom of the switch band to align the booster. The two pins on the upper edge prevent the av-bay from being installed upside down, and makes sure the payload tube aligns with the PEM nuts and screw holes for attaching the payload tube to the upper section of the payload. Since the booster is aligned with the rail button installed, the alignment makes sure the pull pins are always facing each side of the rocket and not toward the rail.


I also use the alignment dowels on the upper payload/nose cone joint. Since this aligns the booster to the bay, to the payload, to the nose cone, I can install the T3 GPS in the nose cone and know the antenna isn't going to be facing the rail and interfering with reception.

The av-bay is the center of the rocket and the av-bay internals and all external tubes are aligned to the av-bay coupler/switch band alignment pins. This insures everything from the nose cone GPS unit to the launch lugs are always assembled in the same alignment, shear pin holes are always aligned and nothing interferes with the launch rail.

 

[Donnager]

I finished the av-bay for my 4" Go Devil. The board with the altimeters and batteries is from a different rocket that had the fin can blown off when I split a case with an EX motor.

This is the Primary altimeter side of the board. The Back Up side is the same. There is one threaded rod on each side so even that is the same. The plywood pieces that hold the batteries have three screws from each side of the board holding them in place. The screw switch and the pull pin switch are in series so the screw switch can turn everything off without needing the pull pin in place while prepping charges. Once everything is prepped, the pull pin is put in and the screw switch is turn on. A little hot glue holds wires in place when needed.
View attachment 532869

I use terminal strips with solder tabs that project through the bottom on the caps.
View attachment 532870

In this case, the drogue side is the short side, so the battery terminals are down and all internals are pushed to the terminal end of the battery during thrust.
The main altimeter uses green and white twisted pairs and the back up altimeter uses blue and white. The main charge wires are long enough the whole sled can be pulled out without having to disconnect any wires. They just get looped together when everything is buttoned up.
View attachment 532871

The hole labeled main is for the screw switch while the pull pin fits through the vent port. There is a single 3/16 fiberglass dowel installed at the joint on the bottom of the switch band to align the booster. The two pins on the upper edge prevent the av-bay from being installed upside down, and makes sure the payload tube aligns with the PEM nuts and screw holes for attaching the payload tube to the upper section of the payload. Since the booster is aligned with the rail button installed, the alignment makes sure the pull pins are always facing each side of the rocket and not toward the rail.
View attachment 532872

I also use the alignment dowels on the upper payload/nose cone joint. Since this aligns the booster to the bay, to the payload, to the nose cone, I can install the T3 GPS in the nose cone and know the antenna isn't going to be facing the rail and interfering with reception.

The av-bay is the center of the rocket and the av-bay internals and all external tubes are aligned to the av-bay coupler/switch band alignment pins. This insures everything from the nose cone GPS unit to the launch lugs are always assembled in the same alignment, shear pin holes are always aligned and nothing interferes with the launch rail.

Is that hot glue you are using for the wire retention? The only reason I ask is I use high temp hot glue rather than drilling multiple holes, or adding brackets, just to replace nylon ties to restrain wires.

Not sure if this is a great method, but it seems to work well.