The Avionics Bay Thread...Post your Photos!

[Velocity Aerospace]

What are your favorite techniques for wire management? Does anyone have any clips they like a lot? I am have been using fairly simple methods such as zip ties, tape, and kevlar thread.

I didn't do it on my new one, but on my old one, I had disks that had small holes in them that I could feed wires through. This allowed me to keep groups of wires together (ejection charges or switch wiring) while keeping them separate from other groups

 

[cwbullet]

What are your favorite techniques for wire management? Does anyone have any clips they like a lot? I am have been using fairly simple methods such as zip ties, tape, and kevlar thread.

I like using zip ties. I have tried with 3d printed versions but they are so cheap.

 

[OverTheTop]

What are your favorite techniques for wire management? Does anyone have any clips they like a lot? I am have been using fairly simple methods such as zip ties, tape, and kevlar thread.

If you are looking for something more permanent, I use Loctite 401 CA adhesive (any CA should work). The wires are tacked onto the sled with a small amount of CA at intervals. Works well.

I also use the same method to stop the ematch wires flapping around, between the charge canisters and connectors. After the flight a chisel easily removes them from the fiberglass bulkheads.

 

[Tractionengines]

After the flight a chisel easily removes them from the fiberglass bulkheads.

(Emphasis added by me.)

This just made me laugh. Thank you...

I am finishing up a 4" AV Bay. Should get a few photos in the next day or two. Eggtimer Quantum, + Quark, with LabRat 2 position switch assembly, and Dog House Rocketry ejection charge mount kits.

 

[BDB]

I’ve been working on a modular AV bay design that can be used for all of my 3” and 4” diameter rockets. I designed “mini sleds” that can hold a single flight computer and lipo battery. Thus far, I have mini sleds for the Eggtimer Quantum and the Blue Raven.

I’ve been using double pull pin switches lately, but I’m a little nervous about the G-forces during flight, so I designed a perpendicular mount that positions the switch mechanism orthogonal to the direction of flight.

It still needs some refinement, but overall, it seems to be working for me. My biggest issue now (as Alex mentioned a few posts ago) is wire management.

 

[BDB]

I also have had success with printed bulkheads (50% infill). I’m a fan of Dog House rocketry charge wells, but I may design my own integrated system in the future.

 

[Kane]

What are your favorite techniques for wire management? Does anyone have any clips they like a lot? I am have been using fairly simple methods such as zip ties, tape, and kevlar thread.

Two methods for me. I 3D print my bays.
1) leave a gap between the threaded rod and tray and just use zip ties.
2) slots/holes along the edge and "weave" the cables in and out

 

[DaHabes]

Just an FYI....I bought a ferrule kit and the smallest one won't fit into the terminal blocks on an Eggtimer Quasar.

The smallest one in kits are generally for 22 gauge wire. I had the same problems on my newer Eggtimer terminal blocks, so I bought 24-26 gauge ferrules here:

https://www.mcmaster.com/catalog/129/856/7950K45
McMaster-Carr is my go-to for all miscellaneous hardware I can't get at a regular hardware store. You can get insulated ferrules for 26-28 gauge, as well.

 

[John Kemker]

What are your favorite techniques for wire management? Does anyone have any clips they like a lot? I am have been using fairly simple methods such as zip ties, tape, and kevlar thread.

Wire management? Huh? I don't understand those words. LOL.

Whatever's handy: zip ties, tape, etc. Sometimes, I just kinda shove it all in and pray.

 

[bad_idea]

Sometimes, I just kinda shove it all in and pray.

The time-honored "tuck and luck" method.

 

[AllDigital]

Here are the ones I buy from McMaster-Carr

 

[John Kemker]

Here are the ones I buy from McMaster-Carr

View attachment 598142

Are the Swedish Fish required for them to work properly?

 

[kjhambrick]

Are the Swedish Fish required for them to work properly?

Aren't Swedish Fish used to plug the thru-ports in the bulkheads when you don't have any chewing gum (*)

-- kjh

(*) shamelessly stolen from @tfish: TRF: Quick change electronics

 

[AllDigital]

Are the Swedish Fish required for them to work properly?

Stripping and crimping a lot of ferrules and then getting that AvBay to fit will work up an appetite. I suppose you could also use the Swedish Fish as a type of pincushion, as long as you lick them clean before putting them in your terminal blocks. They are each the perfect dimension to hold about 6-8 ferrules. (note, McMaster only ships fish in standard sizes and not metric)

 

[tfish]

Aren't Swedish Fish used to plug the thru-ports in the bulkheads when you don't have any chewing gum (*)

-- kjh

(*) shamelessly stolen from @tfish: TRF: Quick change electronics

Yep..Swedish fish could be used in a pinch..
And, I happen to be a fan of them. Had a large bag with me at Aeronaut.

Tony

 

[anbhtblr]

I also have had success with printed bulkheads (50% infill). I’m a fan of Dog House rocketry charge wells, but I may design my own integrated system in the future.

View attachment 598008

Here is my 1st attempt at a printed bulkhead with integrated charge wells. My charge wells have side openings so they act like minimal baffles. I've flown the charge well design several time with good results. I don't see any reason an itegrated charge well won't work as well.

 

[R3verb]

Alright, I'll bite. Here's mine for a BT-60 airframe. This is part of my project to make an Estes Star Orbiter dual deploy (thread here).


There's still some work to do (I need to get the battery and screw switches delivered so that I can add them into the design. I did have a few questions that maybe you can all help with (this is my first e-bay after all).

-My current plan is to use the christmas light method for the BP charges. It seemed like a very easy way to go. Thoughts? Has anybody had good/bad experiences with them? I'm open to other methods, this just seemed like one that would work in such a tight space.
-Currently my BP charges are going to be RIGHT next to my shock cord (300lb kevlar string). Is this a bad idea? Do I need to move the black powder further away from the rings? I may also go with quick links to try and move the string further from the charges.
-During prototyping I'm using PLA. For the final product I'm thinking I'll go PETG. Any suggestions? Has anybody flown a fully 3d printed e-bay before (including the attachment points).
-I see a lot of people going with a small ring of body tube around the middle for switches and stuff. Looking at the Apogee components e-bays, they don't do that. They just have a hole in the airframe and the coupler. Any advice here? I can do either but wanted to see if there's a good reason to go one way or the other.

If anybody wants the files to tinker with themselves, you're more than welcome to them, just let me know. Everything is parametric so conceivably you could take these designs, plug in the ID of your body tube and scale it to any size you wanted. After a few flights and some testing, I may design a bunch to work with different flight computers/body tubes and post them on printables.

Casey Levinger

 

[kjhambrick]

@R3verb --

I REALLY like your Sled !

I too started out with an Apogee Sled for a BT55 but I replaced the fore and aft ears with a replaceable Kevlar loop running around the perimeter of the sled because the ears ate too much vertical space in my drogue and main recovery areas.

This was my first stab: SOLVED: Additive Aerospace Simple Circuit -plus- Featherweight Mag Switch -and- Blue Raven -- It REALLY is This Simple ! and I'll be flying it soon but I want to build a version 0.0.2 because of a couple mistakes and ideas for improvement ...

I am not done with version 0.0.2 yet but I'll post a picture when I have something to show.

My new sled is 0.9 inch wide including a loop of replaceable 750 lb Kevlar around the perimeter instead of the Apogee Plywood Ears.

Like your sled, there is no load on the bulkheads -- all the load is borne by the sled ( in my case, the Kevlar loop ).

The electronics on the sled, fore -to- aft are: Featherweight Mag Switch, Additive Aerospace Simple Circuit and a Featherweight Blue Raven and they require 4-inches of linear space on the sled.

I plan on using the same sled in 29mm and 38mm as well as BT-55 and Aerotech 1.9 inch Air Frames.

All I have to do is change the bulk plates and the coupler tube to fly the electronics in a different rocket.

I am using a Featherweight Mag Switch so there is no need for a switch band -- the only openings to the atmosphere are three 1/8 inch ports for the Blue Raven Barometric Sensor.

How do you arm your electronics -- you might need access for arming ?

I've never used Christmas Tree Bulbs -- I've always used e-matches instead.

I always place my BP charges behind the shock cord and chute so that the recovery devices are pushed out by the pressure.

My drogue is usually far enough away from the BP that I just use dog barf.

My main chute and the anchor loop are adjacent to the BP so I usually wrap my Kevlar anchor loop and an inch-or-so of the shock cord near the BP charge with a little masking tape.

In smaller rockets I usually connect the recovery stuff with 50 lb Zip Ties but I am experimenting with soft shackles so I may use those instead.

HTH !

-- kjh

 

[Tractionengines]

54mm sled, put together quick for a MAC Performance kit, I picked up last year.
LabRat, pull-pin switch
Eggtimer, Mini-WiFi Switch
Eggtimer, Quark altimiter
Additive Aerospace Aluminum u-bolt
Dog House Rocketry, Charge Mount Kit
Generic liPo, 2S, 450mAh, 20C
(The pull pin is to extend the life of the battery, since the Mini-WiFi switch does use power whenever it has power into it.)

 

[BDB]

Alright, I'll bite. Here's mine for a BT-60 airframe. This is part of my project to make an Estes Star Orbiter dual deploy (thread here).
View attachment 600037View attachment 600038View attachment 600039

There's still some work to do (I need to get the battery and screw switches delivered so that I can add them into the design. I did have a few questions that maybe you can all help with (this is my first e-bay after all).

-My current plan is to use the christmas light method for the BP charges. It seemed like a very easy way to go. Thoughts? Has anybody had good/bad experiences with them? I'm open to other methods, this just seemed like one that would work in such a tight space.
-Currently my BP charges are going to be RIGHT next to my shock cord (300lb kevlar string). Is this a bad idea? Do I need to move the black powder further away from the rings? I may also go with quick links to try and move the string further from the charges.
-During prototyping I'm using PLA. For the final product I'm thinking I'll go PETG. Any suggestions? Has anybody flown a fully 3d printed e-bay before (including the attachment points).
-I see a lot of people going with a small ring of body tube around the middle for switches and stuff. Looking at the Apogee components e-bays, they don't do that. They just have a hole in the airframe and the coupler. Any advice here? I can do either but wanted to see if there's a good reason to go one way or the other.

If anybody wants the files to tinker with themselves, you're more than welcome to them, just let me know. Everything is parametric so conceivably you could take these designs, plug in the ID of your body tube and scale it to any size you wanted. After a few flights and some testing, I may design a bunch to work with different flight computers/body tubes and post them on printables.

Casey Levinger

I love your design too. How do you get the coupler tubing (shown in the first pic) onto the sled?

Is it two halves of tubing cut longways? If so, I’ve always wanted to do something like that because the removable bulkhead in most AV bay designs is kind-of a pain in the butt.

 

[DaHabes]

Here's my latest iteration.

3D printed stepped bulkheads, 100% infill (have to be able to take shock cord forces). I created these using the Rocket workbench in FreeCAD.

3D printed sled. I have offset the rods so I could use the Lab Rat Rocketry pull-pin switches. I created this sled by modifying the OpenScad E-Bay Designer module (you can find it in the 3D Printing forum).

I use aluminum rods to avoid attenuation of the tracker signal. Putting the tracker in the E-Bay protects it better than in the nose cone (in case of a lawn dart) and lets me use the pull-pin switch to activate it along with the altimeters. I can also use a different tracker in the nose cone for redundancy if desired (will be using EggFinder Mini in my L3 rocket).

1/2" copper tubes for the charge wells. I use centrifuge tubes for the BP that fit in these, so no cleanup of the charge wells.

Stainless steel posts with knurled nuts for e-match attachments. No wires coming through the bulkhead.

Eggtimer Quantum for primary, Eggtimer Quark as backup behind an Eggtimer WiFi switch, Featherweight GPS tracker.

I have built this in both 3" and 4" sizes. Will build identical 6" E-Bay for my L3 rocket.

I lay out the components and hand drill the holes for attaching the electronics and zip tie connections. The terminal connections at the drogue end are permanently attached, as are the rods with stop nuts. The main end has JST connectors internally and wing nuts on the rods. The entire E-bay will be moved between rockets with only the coupler and switch band being dedicated to the rocket (so the switch band paint matches the rocket). This minimizes the amount of un-connect/reconnect actions, which is the weak point in any design. It also minimizes the number of electronics I need, just one set for each diameter rocket.

 

[cwbullet]

Here's my latest iteration.

3D printed stepped bulkheads, 100% infill (have to be able to take shock cord forces). I created these using the Rocket workbench in FreeCAD.

3D printed sled. I have offset the rods so I could use the Lab Rat Rocketry pull-pin switches. I created this sled by modifying the OpenScad E-Bay Designer module (you can find it in the 3D Printing forum).

I use aluminum rods to avoid attenuation of the tracker signal. Putting the tracker in the E-Bay protects it better than in the nose cone (in case of a lawn dart) and lets me use the pull-pin switch to activate it along with the altimeters. I can also use a different tracker in the nose cone for redundancy if desired (will be using EggFinder Mini in my L3 rocket).

1/2" copper tubes for the charge wells. I use centrifuge tubes for the BP that fit in these, so no cleanup of the charge wells.

Stainless steel posts with knurled nuts for e-match attachments. No wires coming through the bulkhead.

Eggtimer Quantum for primary, Eggtimer Quark as backup behind an Eggtimer WiFi switch, Featherweight GPS tracker.

I have built this in both 3" and 4" sizes. Will build identical 6" E-Bay for my L3 rocket.

I lay out the components and hand drill the holes for attaching the electronics and zip tie connections. The terminal connections at the drogue end are permanently attached, as are the rods with stop nuts. The main end has JST connectors internally and wing nuts on the rods. The entire E-bay will be moved between rockets with only the coupler and switch band being dedicated to the rocket (so the switch band paint matches the rocket). This minimizes the amount of un-connect/reconnect actions, which is the weak point in any design. It also minimizes the number of electronics I need, just one set for each diameter rocket.

View attachment 600103View attachment 600102View attachment 600101View attachment 600100

Nice. What can be done can be overdone. Not a swipe. It is a well-designed and beautiful Av-Bay,

 

[RobRoy]

Where did you get the stainless steel posts with knurled nuts? Looks like a great solution .

 

[Tractionengines]

Here's the 4", the power wires are finalized... I may tweak the charge leads a little bit. (That's why where not "secured" to the sled yet.)

LOC Precision 4" AV Bay
LabRat 2 position pull pin switch
Eggtimer Quark
Eggtimer Quantum
Generic 2S, 450mAh Li-po
DogHouse Rocketry charge wells

 

[0011001100]

3 inch long coupler for my 29mm Blackhawk. Raven 2 with the 29mm ebay kit. Top is an integrated charge well based on a piece of carbon arrow shaft for the drogue. Bottom will have a dangling charge for the main.

Next up is the nosecone to house the featherweight tracker.

 

[R3verb]

Ok, V2 of the 3D printed e-bay is done. I finally got some switches and the battery so I could design those into the model. The top is basically the same minus moving the Telemetrum around a bit:



I did add some notches for zip ties inspired by the Badass Rocketry sled. I need to move these around for V3 as some of them interfere with other elements of the sled (hooray for rapid prototyping).

The big changes are the back:



Going from left to right, the updates are:

-A 3D printed doghouse for the battery. I got the size wrong on this iteration so it's just held with a velcro strip but in the final version there will be a screw-on top that secures it in place.
-Battery retention screw hole. If you look at the top of the battery, there's a little standoff. Add this to the lid ontop of the space for the lipo and it will be held in on all sides.
-Integrated pull pin switch! I'm honestly most proud of this. I'm using a limit switch (they were like 10 for $8 on Amazon) and then the little 3d printed house that goes over it gets the pin to depress the switch when inserted. In the next version I want to add some material around the side of the switch to help hold it in place even more. I do want to point out something I found interesting that I haven't seen in this thread. MOUNT YOUR SWITCHES UPSIDE DOWN! When thinking orientation through, originally I had the switch the other way but in thinking about it, placing this switch this way means that G-force forces the switch OPEN which is what you want with this kind of switch. I don't think it would be a big deal with this size rocket but I could see something with a lot of G loading ending up pushing the switch closed at takeoff.

So, I do have a few questions:

-I'm using this battery (https://www.apogeerockets.com/Electronics-Payloads/Electronics-Accessories/120mAh-LiPo-Battery). It's a 1 cell 3.7v lipo. I went with the tiny one to save weight/space. Is this going to be enough? I assume it's got the same punch as the bigger 400 and 800mah batteries but I wanted to see if anybody has run this battery with the Telemetrum. I don't expect this will idle on the pad more than like 15 minutes based on what I've seen at my local launches.
-Switch retention. My limit switch in this picture is held in with plastic screws screwed directly into the plastic sled. I have some metal ones that I could swap out but they won't thread in quite as far into the plastic. So the question is, what's more likely to fail, the plastic screws or the threading into the sled. Thoughts?

Finally, to answer some questions:

I love your design too. How do you get the coupler tubing (shown in the first pic) onto the sled?

There are two bumps, one at each end of the sled that hold an M3 bolt. One of the bulkheads will be epoxied into the tube and the other will be connected to the sled. The sled will slide into the slot on the bulkhead attached to the coupler tube and then a little m3 nut attaches everything.

How do you arm your electronics -- you might need access for arming ?

Added the pull pin arming switch in this iteration. I had always known I'd need some sort of switch, just wasn't sure what I was going to use but this seems like the clear winner.

Any other advice is welcome!

casey

 

[OzHybrid]

You could make it so you can get a loop of kevlar around both eyes. Like a rope eye thimble. At the moment, if your print fails, you've got nothing to save you. Also gives you no metal in the AV bay. You can do that with a tunnel on the AV mounting area on the battery side and could make a wall for the battery at the same time.

 

[R3verb]

V3.1 is done and it’s ready to fly! I made a few modifications to the layout and got the battery box just right. It’s been like 2 weeks of CAD and 3D printing but it’s all put together and this will be the one the flies.




The closures took some perfecting as well. Since the coupler tube is a BT-60 cut lengthwise and then fiberglassed back together it wasn’t perfectly circular it took some trial and error getting the fit just right.


Hope this helps somebody! If you want to print one for yourself let me know and I’m happy to share the CAD files.

 

[Hobie1dog]

V3.1 is done and it’s ready to fly! I made a few modifications to the layout and got the battery box just right. It’s been like 2 weeks of CAD and 3D printing but it’s all put together and this will be the one the flies.

View attachment 608262
View attachment 608263

The closures took some perfecting as well. Since the coupler tube is a BT-60 cut lengthwise and then fiberglassed back together it wasn’t perfectly circular it took some trial and error getting the fit just right.
Hope this helps somebody! If you want to print one for yourself let me know and I’m happy to share the CAD files.

 

[kjhambrick]

V3.1 is done and it’s ready to fly! I made a few modifications to the layout and got the battery box just right. It’s been like 2 weeks of CAD and 3D printing but it’s all put together and this will be the one the flies.

View attachment 608262
View attachment 608263

The closures took some perfecting as well. Since the coupler tube is a BT-60 cut lengthwise and then fiberglassed back together it wasn’t perfectly circular it took some trial and error getting the fit just right.
View attachment 608264

Hope this helps somebody! If you want to print one for yourself let me know and I’m happy to share the CAD files.

@R3verb --

That is a beautiful AV-Bay !

I have been working on something similar where I could swap the same sled among a set of couplers and bulkheads ( 29, 34, 38, 48 mm ) but mine is made from 1/8 plywood since I've got no 3D printing capability here.

Like @OzHybrid, I was worried about tension loads on the sled at ejection, especially with larger motors so I am working on adding a Kevlar loop around the perimeter of the sled.

I wanted to plan on flying up to a J570 in a 38mm min diameter rocket.

A J570 is pretty massive when empty and the G-loads at ejection and when the chutes deploy will be high so I didn't trust the Apogee pure-plywood design which is why I am messing with the Kevlar loop and eliminating the plywood ears in mine ...

I am working with hand tools so the going is slow but I'll post some pics when I have something to show.

How much mass do you anticipate on either end of the sled for your rocket(s) ( i.e. fincan on the south-side -vs- nose on the north-side ) ?

Thanks for the pictures and the great ideas !

-- kjh