First Time AV-bay construction Thread

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I forgot to mention, I decided to have the stick LiPo batteries power the flight computers just as a safety measure since they have the same capacity, but a higher discharge rating (25C vs 95C 450mah)
 
RRC3 has a manufacturer recommendation of 9v battery.
It works from 3.5v to 10v DC. I can get two 9v battery's worth of battery in the same space with LiPos. In this situation, where I want to use every single cubic centimeter of space, LiPos are the way to go, plus most 9v batteries max out at 2.5A but you can find some that go up to 5.5A if youre careful what you choose. The 25C lipos are rated for 12A and can likely spike to 20A, and the 95C lipos are rated for 50A. Just as a preventative measure to make SURE the ematches fire. (and I do realize that 50A is way overkill lol)
 
It works from 3.5v to 10v DC. I can get two 9v battery's worth of battery in the same space with LiPos. In this situation, where I want to use every single cubic centimeter of space, LiPos are the way to go, plus most 9v batteries max out at 2.5A but you can find some that go up to 5.5A if youre careful what you choose. The 25C lipos are rated for 12A and can likely spike to 20A, and the 95C lipos are rated for 50A. Just as a preventative measure to make SURE the ematches fire. (and I do realize that 50A is way overkill lol)

Be careful! The output side of the RRC3 is only rated to handle 3A. Pushing 12A, 20A, or 50A is very likely to fry your altimeter.

Try it, learn a lesson, and then re-buy it. It's a great altimeter. :)
 
Be careful! The output side of the RRC3 is only rated to handle 3A. Pushing 12A, 20A, or 50A is very likely to fry your altimeter.

Try it, learn a lesson, and then re-buy it. It's a great altimeter. :)
thanks for the heads up! Wasnt really intending to push 50A through an Ematch. but thanks anyways!
 
It works from 3.5v to 10v DC. I can get two 9v battery's worth of battery in the same space with LiPos. In this situation, where I want to use every single cubic centimeter of space, LiPos are the way to go, plus most 9v batteries max out at 2.5A but you can find some that go up to 5.5A if youre careful what you choose. The 25C lipos are rated for 12A and can likely spike to 20A, and the 95C lipos are rated for 50A. Just as a preventative measure to make SURE the ematches fire. (and I do realize that 50A is way overkill lol)

Guess you do you, as you know better than the manufacturer.
 
Guess you do you, as you know better than the manufacturer.
Many, many, many of us have been using MW computers with Lipos for years now without a single battery related issue. I've had several conversations with the vendor about it as well, and the concerns are well understood......and have not manifest! Most folks I know flying MW computers no longer even bother with the 'safety resistors' anymore either because we've simply NOT had an issue.

So, yeah, we'll keep doing it and continuing to prosper!
 
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Also, does anyone know if there is a way to either return an eggtimer for replacement, or fix error code 2 on the eggtimer classic?? I asked Cris twice, but both times he's kinda left me hanging(once in this forum, he replied once, and then never replied again, and then I waited a few days and sent him a support email). I sent a support email a couple days ago, but havent gotten anything back except the automated reply email.
 
Also, does anyone know if there is a way to either return an eggtimer for replacement, or fix error code 2 on the eggtimer classic?? I asked Cris twice, but both times he's kinda left me hanging(once in this forum, he replied once, and then never replied again, and then I waited a few days and sent him a support email). I sent a support email a couple days ago, but havent gotten anything back except the automated reply email.
Pretty sure I replied back... check your Spam folder. I'll resend my Reply. FYI, that's a baro sensor out of bounds error...
 
:"terminal block" is just long hand for "failure points" just make a hole you can feed your ematch directly to the altimeter. this gets rid of the following failure points: terminal block to altimeter connection, terminal block wire, terminal block, terminal block to terminal wire connection, charge to terminal block connection in a dirty environment.

just sayin"
 
:"terminal block" is just long hand for "failure points" just make a hole you can feed your ematch directly to the altimeter. this gets rid of the following failure points: terminal block to altimeter connection, terminal block wire, terminal block, terminal block to terminal wire connection, charge to terminal block connection in a dirty environment.

just sayin"
I'd also like to keep the terminal block section of the PCB on my flight computers in the event of the charge getting ripped at. Which is why I'm not doing that...
 
I'd also like to keep the terminal block section of the PCB on my flight computers in the event of the charge getting ripped at. Which is why I'm not doing that...
You could always put an overhand knot in your ematch lead on the backside of the bulkhead, to ensure that if your charge gets snagged during deployment, it is not going to pull the terminal block off the altimeter.

And if you are using charge wells, I would imaging the chances of the ematch lead getting snagged are further lessened.
 
I understand the "failure point" thinking with terminal blocks, but after using terminal blocks on all of my av-bays for 15 years, I've never had any issue or failure that could remotely be attributed to a terminal block or connection issue. I feel the chance of a commercial ematch failing (I've had several over the years) is much higher than the chance of a failure of the connection between the altimeter and ematch when using terminal blocks. In my opinion, almost all failure modes have a higher chance of occurring than a connection failure at a terminal block. In my opinion, eliminating the terminal block adds such a minute and minimal increase in the dependability of the electronics, increases the chance of gases and pressure spikes reaching the altimeter and affecting it's dependability, that it is detrimental compared to the convenience, simplicity of setup, and dependability when a terminal block is used. That is why I still continue to use terminal blocks on all my av-bays. YMMV
 
You could always put an overhand knot in your ematch lead on the backside of the bulkhead, to ensure that if your charge gets snagged during deployment, it is not going to pull the terminal block off the altimeter.

And if you are using charge wells, I would imaging the chances of the ematch lead getting snagged are further lessened.
I could do that, but I've decided to go with the WAGO connectors, and I want to try them. Plus i see no large inherent risk with using an extra JST connection between the charges and the FC, if it's good enough for the main battery connection, it's good enough for the pyro charges
 
:"terminal block" is just long hand for "failure points" just make a hole you can feed your ematch directly to the altimeter. this gets rid of the following failure points: terminal block to altimeter connection, terminal block wire, terminal block, terminal block to terminal wire connection, charge to terminal block connection in a dirty environment.

just sayin"
The only trouble there is that the terminal strips that the manufacturers use on the altimeter circuit boards are not rated for that many cycles overall. They're meant for 'assemble and leave it unless you need to troubleshoot or rewire it for upgrades' type installations, not 'in/out/in/out ad infinitum' use.
 
I'd also like to keep the terminal block section of the PCB on my flight computers in the event of the charge getting ripped at. Which is why I'm not doing that...
If that happens, to quote a show......
you're doing it wrong
you're doing it wrong
you're doing it wrong

so, how could that happen, anyway? you tape over the hole the wire goes thru, the charge pressurizes the compartment, pressing everything down and preventing relative motion between the two.....

science!
 
That sounds like what I did on my L1 cert rocket. It was my first scratch build HPR and first DD rocket. It was also the last time I didn't use charge wells. I didn't have any issues with the match wires damaging the av-bay, but there were a couple times they broke near the terminal block because they got jerked hard. Just make sure the match wire comes loose or breaks before the WAGO pulls loose from the av-bay cap and starts pulling the wires through the cap.
While I agree that charge wells are not needed/required, I use them for better control of the charge. The attached pictures show a newly 3D printed charge well and a bulkhead from my Mad Cow Super DX3 (fiberglass) following it's fifth (5th) flight. The charge well is printed with a cavity for the charge and locations for the through bulkhead machine screws that I use as connectors. I place the charge and match in a glove tip, run the match wire through the slot in the charge well top, pack with a little bit of dog barf (to help stabilize the charge and hold the powder in place during ignition) and cover the cavity opening with masking tape. This is all done at home before going to the launch. At the launch site I connect the match leads to the through bulkhead machine screws and button up the bird. These well are meant to contain/redirect hot particle from going directly into the airframe cavity. Note on the bulkhead there are also deflectors meant to protect the shock cord connection point from hot particles. With this technique and careful burrito packing I've not had any problems with laundry and shock cord suffering from ejection. So, charge wells needed - no. For me, charge wells are desired.
 

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While I agree that charge wells are not needed/required, I use them for better control of the charge. The attached pictures show a newly 3D printed charge well and a bulkhead from my Mad Cow Super DX3 (fiberglass) following it's fifth (5th) flight. The charge well is printed with a cavity for the charge and locations for the through bulkhead machine screws that I use as connectors. I place the charge and match in a glove tip, run the match wire through the slot in the charge well top, pack with a little bit of dog barf (to help stabilize the charge and hold the powder in place during ignition) and cover the cavity opening with masking tape. This is all done at home before going to the launch. At the launch site I connect the match leads to the through bulkhead machine screws and button up the bird. These well are meant to contain/redirect hot particle from going directly into the airframe cavity. Note on the bulkhead there are also deflectors meant to protect the shock cord connection point from hot particles. With this technique and careful burrito packing I've not had any problems with laundry and shock cord suffering from ejection. So, charge wells needed - no. For me, charge wells are desired.
I really like that redirect out the side instead of into the BT. I might have to try that.
 
I understand the "failure point" thinking with terminal blocks, but after using terminal blocks on all of my av-bays for 15 years, I've never had any issue or failure that could remotely be attributed to a terminal block or connection issue. I feel the chance of a commercial ematch failing (I've had several over the years) is much higher than the chance of a failure of the connection between the altimeter and ematch when using terminal blocks. In my opinion, almost all failure modes have a higher chance of occurring than a connection failure at a terminal block. In my opinion, eliminating the terminal block adds such a minute and minimal increase in the dependability of the electronics, increases the chance of gases and pressure spikes reaching the altimeter and affecting it's dependability, that it is detrimental compared to the convenience, simplicity of setup, and dependability when a terminal block is used. That is why I still continue to use terminal blocks on all my av-bays. YMMV
Maybe I am overthinking all of this....

I am building a DD av-bay and intend to use the terminal blocks on the outside of the bulkheads as you have. Can you assist in answering these questions: Does your av-bay have a fixed bulkhead on one end of the coupler tube, or is the bulkhead affixed to the sled on one end? Either way, or if neither bulkheads are affixed at all (only by way of all-thread), then the coupler tube must slide on from one end of the sled to have the fit needed. That would mean that the wires that run from the terminal block(s) on the external side of one of the bulkheads back to the main or drogue connection on the altimeter, must be quite long as the connection to the altimeter would need to be exposed before the av-bay is buttoned up. I have an RRC3 and I figured I could run those longer wires (twisted) through two or so simple cable/wire runs on the inner wall of the coupler tube to avoid a rats nest of wire. The wire would be exposed at the opposite end and connected to the RRC3 just as the sled is being pushed into the tube. The opposite end bulkhead terminal block wires could be simply run to the RRC3, as perhaps those wires would be much shorter and already exposed.

Your thoughts on this diatribe? !!!!!
 
Maybe I am overthinking all of this....

I am building a DD av-bay and intend to use the terminal blocks on the outside of the bulkheads as you have. Can you assist in answering these questions: Does your av-bay have a fixed bulkhead on one end of the coupler tube, or is the bulkhead affixed to the sled on one end? Either way, or if neither bulkheads are affixed at all (only by way of all-thread), then the coupler tube must slide on from one end of the sled to have the fit needed. That would mean that the wires that run from the terminal block(s) on the external side of one of the bulkheads back to the main or drogue connection on the altimeter, must be quite long as the connection to the altimeter would need to be exposed before the av-bay is buttoned up. I have an RRC3 and I figured I could run those longer wires (twisted) through two or so simple cable/wire runs on the inner wall of the coupler tube to avoid a rats nest of wire. The wire would be exposed at the opposite end and connected to the RRC3 just as the sled is being pushed into the tube. The opposite end bulkhead terminal block wires could be simply run to the RRC3, as perhaps those wires would be much shorter and already exposed.

Your thoughts on this diatribe? !!!!!
I just finished my V3 sled (ill post pix later) which is the final version i intend on doing. my bulkheads, my sled, and my coupler are all 3 seperate parts, and are bolted together with a 1/4in allthread. All my wiring is internal except the points where i have to connect the WAGO connectors to a jst connector to connect the outside to the inside. A nice part about the WAGO connectors is that I can have my charges prepared, and my flight computers connected to power, but the charges dont need to be connected to the connectors until im at the pad, where i can connect the charges, put it back together, slide it on the rail, pull the pin, and listen for my beeps and then go. I'm pretty sure my longest wire run is about 3in from the RRC3 to the terminal blocks.
 
My bulkheads are held in place by wing nuts on the threaded rods. I use short runs of twisted wire (connected in a drill and spun to twist together) The wires from the one end cap to the altimeters is long enough to pull the whole sled out of the coupler without having to disconnect anything. The long wires could be 2x to 3x as long and still have no effect on the operation of the matches.

I use a pull pin switch in series with a screw switch that is accessed though the coupler that slides into the booster. That way the payload can be attached while still having access to the screw switches. That allows turning off the altimeters without having to insert the pull pins. You just need to remember to turn on the screw switches after the pins are inserted as you do your final assembly before heading to the RSO.

20220816_131117.jpg
 
Here's my final version of my sled, I skipped V2 and just decided to put it all in one big post. OK so changes, i had to slant the eggtimer classic to allow for the eyebolt to fit into the sled and also allow the pull pin switch to fit in the small space available in the area of the switch band. I also added gaps larger gaps between the bulkplate and some sections of the sled to allow the JST leads to fit into the bay, and go through the bulkplate through my holes and into the WAGO connectors. I also decided to forgo the eggfinder mini batteries wired in parallel, which would cause even more of an octopus rat's nest of a wiring situation and just hooked the second battery up to the eggtimer classic. I also added in a gap for the 450mah flatpacks to actually fit inside the av bay. Questions are very much appreciated :)
 

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I just finished my V3 sled (ill post pix later) which is the final version i intend on doing. my bulkheads, my sled, and my coupler are all 3 seperate parts, and are bolted together with a 1/4in allthread. All my wiring is internal except the points where i have to connect the WAGO connectors to a jst connector to connect the outside to the inside. A nice part about the WAGO connectors is that I can have my charges prepared, and my flight computers connected to power, but the charges dont need to be connected to the connectors until im at the pad, where i can connect the charges, put it back together, slide it on the rail, pull the pin, and listen for my beeps and then go. I'm pretty sure my longest wire run is about 3in from the RRC3 to the terminal blocks.
My bulkheads are held in place by wing nuts on the threaded rods. I use short runs of twisted wire (connected in a drill and spun to twist together) The wires from the one end cap to the altimeters is long enough to pull the whole sled out of the coupler without having to disconnect anything. The long wires could be 2x to 3x as long and still have no effect on the operation of the matches.

I use a pull pin switch in series with a screw switch that is accessed though the coupler that slides into the booster. That way the payload can be attached while still having access to the screw switches. That allows turning off the altimeters without having to insert the pull pins. You just need to remember to turn on the screw switches after the pins are inserted as you do your final assembly before heading to the RSO.

View attachment 576471
A bit confused on this one. Am I right that the pull pin switch and the screw switch both be accessed from outside the air frame? Then you insert the pin into the switch once the avbay is in the booster, with the screw switch off. Then put the payload in place with access to the screw switch, get on the pad, turn the screw switch on, pull the pin from the pin switch. The system is now turned on and armed??? After recovery you can turn the system off with the screw switch. Correct?
 
My bulkheads are held in place by wing nuts on the threaded rods. I use short runs of twisted wire (connected in a drill and spun to twist together) The wires from the one end cap to the altimeters is long enough to pull the whole sled out of the coupler without having to disconnect anything. The long wires could be 2x to 3x as long and still have no effect on the operation of the matches.

I use a pull pin switch in series with a screw switch that is accessed though the coupler that slides into the booster. That way the payload can be attached while still having access to the screw switches. That allows turning off the altimeters without having to insert the pull pins. You just need to remember to turn on the screw switches after the pins are inserted as you do your final assembly before heading to the RSO.

View attachment 576471
And… the purplish/white twisted wires are hook to each bulkhead only???
You got me on this one!
 
A bit confused on this one. Am I right that the pull pin switch and the screw switch both be accessed from outside the air frame? Then you insert the pin into the switch once the avbay is in the booster, with the screw switch off. Then put the payload in place with access to the screw switch, get on the pad, turn the screw switch on, pull the pin from the pin switch. The system is now turned on and armed??? After recovery you can turn the system off with the screw switch. Correct?
Yes, there is a redundant altimeter on the opposite side of the sled.

The pull pin turns off the altimeter when the pin is inserted. The screw switch is only accessable when the lower part of the coupler is lifted out of the booster BT. I recommend putting the screw switch near the switch band so you don't have to slide the whole couple out of the booster BT to turn it on or off.

If you look at the sled, there is only one threaded rod on each side of the sled. This allows building both sides identical. It also allows putting the pull pin switch and screw switch along the edge of the sled, opposite of the threaded rod on that side.

My normal method of prepping is, without the pull pins inserted, to connect all 4 ematches and then turn on each screw switch to verify the altimeters are operating, the battery voltages are sufficient, and both ematches are showing connection and continuity on each altimeters. I then turn off the screw switches and load the powder charges. The av-bay is then inserted and connected to shock cords and payload tube. Once the rocket is all prepped, motor loaded, recovery all set, GPS units installed in the nose cone, and nose cone shear pins installed, the last step before going to the RSO is to install the pull pins, turn on the screw switches, and install any shear pins for the booster section.

Once on the pad, just pull the pins to arm the altimeters and charges.
 
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