Quick Build - Apogee 29mm Electronics Bay

[PhysicsGuy]

Although I've been level 1 for many years, I have never flown dual deploy. I always wanted to learn and now I finally have the time.

In looking around at some of the various electronics bays from the various vendors, I came across this 29mm ebay from Apogee. I was intrigued because I had never envisioned doing something this small. Also, I have an unfinished Apogee Aspire in my build pile. The Aspire is designed to go high on mid-power motors and this ebay will help me get it back. Plus, this allows me to get started on a rocket that is not too big/expensive just in case something goes wrong.

So, I picked up the kit and will post a few photos and my experience with the flight. If you have also built this ebay, please add your experiences and/or recommendations.

Here's a look at the kit. The sled and bulkheads are of laser cut plywood. I found the quality to be very high. As I removed the parts, they took very little sanding to clean them up. The parts fit together very well. There are even some tiny spacers cut out of the plywood for mounting the altimeter.

My only issue with the kit was a missing part. The short white section of body tube was not included with my kit. Luckily, I had some 29mm thin wall tubing on hand and just cut a new piece.

Apogee has a series of videos on assembling and flying this ebay. You can find them on their catalog web page.

The sled has holes already laser cut for the Altus Metrum EasyMini or PerfectFlite StratoLogger CF. I will use mine with the PerfectFlight.



--MARK
NAR 65148, L1

 

[Funkworks]

... If you have also built this ebay, please add your experiences and/or recommendations.

I ordered the 2.6" version a few months ago before I even had a mid-level rocket to put it in, just so I'd have something to tinker with. I also learned a lot from the videos.

I got the EasyMini altimeter to use it with, but after I installed it with 4 washers, as per the instructions, I couldn't plug the USB cord in the port, so I had to go back and raise the altimeter using all 8 that were included (I see you have the same 8 wooden washers).

I also had to order an extra switch, because despite my best efforts, CA glue got into the first one and you can guess what that did. So be extra careful with that step.

Overall, I'm very pleased.

 

[PhysicsGuy]

I got the EasyMini altimeter to use it with, but after I installed it with 4 washers, as per the instructions, I couldn't plug the USB cord in the port, so I had to go back and raise the altimeter using all 8 that were included (I see you have the same 8 wooden washers).

I remember seeing the USB connection in the Apogee video. There is a slight indentation cut in the side of the sled (barely visible in the photo above) to provide fit for the USB connector. It's not much of an indentation, though, so I can see why it might not fit. Fortunately, the data connector for the StratoLogger is on the top of the board, so the connection shouldn't be an issue.

--MARK

 

[PhysicsGuy]

Making some progress. I have the sled and the bulkheads assembled.

The instructions from Apogee are incredibly detailed and well illustrated. There are 7 pages of instructions on building and flying the 29mm electronics bay. As a beginner at dual deployment, I appreciate all the extra detail.

Most of the work is done with wood glue. There are a couple of steps that recommend thick CA (attaching the power switch and the weld nut), but I didn't have any on hand. So, I mixed up some 30 min epoxy and all is well. Here's a picture of the assembled sled and coupler tubes. The forward bulkhead is permanently attached to the sled. The aft bulkhead slides onto the end and is secured with a small thumbscrew.

Picture shows an Estes E12 for comparison. Next up is mounting the electronics and wiring for the switch and battery.

 

[mbeels]

I haven't built that kit, but mid-power dual deploy is a ton of fun! Packing the electronics into a small bay can be a challenge, but it looks like that kit will help with the process and give you a neat result in the end. Here are a few shots of my av-bay, it is an Eggtimer Classic in a BT-55 (33mm). I used dual batteries; a 100 mAh lipo powers the flight computer, and a 400 mAh fires the charges. Switches are home made screw switches. It's got a bunch of flights on Ds and Es.

The next time, I'll make some changes. For one, I'll use allen head screws instead of flat heads. With the rocket sitting on the launch pad, a hex driver is much easier to get in place than a flat head.

How are you going to hold the charges? I loaded them into centrifuge canisters, sealed off with ear plugs, it works well.

 

[PhysicsGuy]

Here are a few shots of my av-bay, it is an Eggtimer Classic in a BT-55 (33mm). I used dual batteries; a 100 mAh lipo powers the flight computer, and a 400 mAh fires the charges. Switches are home made screw switches.

Thanks for adding your pictures. Nice design. I like how you've been able to incorporate two batteries. I don't think mine is going to have space for a second battery, but I will do some test fitting as it comes together.

How are you going to hold the charges? I loaded them into centrifuge canisters, sealed off with ear plugs, it works well.

I haven't decided yet how I will do the charges. Apogee suggests the fingertip of a rubber glove. I like the idea of the centrifuge canister. In our club, there are flyers that routinely use both of these. I also like the idea of a small charge well. I have one of the small charge wells from Binder/Dog House and it will fit on the forward bulkhead. I would probably have to epoxy it in place rather than using the screw.....the screw would come thru right where the battery is located. The small charge well is designed to hold about 0.5 grams of BP and that will be sufficient for the size of rockets I'm planning. I enjoy "experimenting" with different approaches, so I may try them all. The aft bulkhead does not have enough space for any kind of charge well if you use it with the supplied thumb screw.

--MARK

 

[captbk]

Thanks for adding your pictures. Nice design. I like how you've been able to incorporate two batteries. I don't think mine is going to have space for a second battery, but I will do some test fitting as it comes together.



I haven't decided yet how I will do the charges. Apogee suggests the fingertip of a rubber glove. I like the idea of the centrifuge canister. In our club, there are flyers that routinely use both of these. I also like the idea of a small charge well. I have one of the small charge wells from Binder/Dog House and it will fit on the forward bulkhead. I would probably have to epoxy it in place rather than using the screw.....the screw would come thru right where the battery is located. The small charge well is designed to hold about 0.5 grams of BP and that will be sufficient for the size of rockets I'm planning. I enjoy "experimenting" with different approaches, so I may try them all. The aft bulkhead does not have enough space for any kind of charge well if you use it with the supplied thumb screw.

--MARK

I do .5 gram charges in my 38mm min diam. and I use the rubber glove finger tips. I dont do the centrifuge tubes because of their size. I fill any free space dog barf.

 

[PhysicsGuy]

Here is the final picture of my electronics bay. Altimeter and power switch are mounted. The switch is wired to the StratoLogger. Routing of the wires is a little more challenging in such a small e-bay, but not too bad.

The battery is in position, but not connected yet. I also purchased the 400 mAh battery from Apogee. It is from Altus Metrum and does not have an over-current protection circuit. The connector is supposed to be a JST-PH, but I had a lot of trouble getting it to mate with other devices like my battery charger and GPS. I suspect the connector is a clone. If I had forced it into the mating connector, I probably would have ripped it apart trying to remove it. I have experienced this with batteries from other vendors. When I do, I will replace the connector with a genuine JST part. They are available from various sources..... lately I've been getting them from Adafruit (part no. 261).

That's about it. Next up will be a little ground testing. Between my schedule and the club's launch schedule, I probably won't get to fly this thing until late July. I'll try to post a report after the flight.

 

[mbeels]

I have that same battery (also from Apogee), but didn't have any issues with the connector. I'm using the Sparkfun lipo charger, and the battery mates properly with that device. I did note that this battery (and the Sparkfun charger) come with positive and negative swapped with respect to most other things that use that JST connector. Is it possible that the black and red leads didn't match your charger and GPS?

 

[PhysicsGuy]

Is it possible that the black and red leads didn't match your charger and GPS?

The problem with my connector was just the poor fit. It was taking an excessive amount of force to get the connector to mate with my other devices. I stopped trying before I broke something. I examined the connector to look for any defects, but didn't see anything obvious. Perhaps I just got a bad one. I have replaced it and everything is working ok.

 

[captbk]

I love how you eliminated any all thread. That could definitely be applied to bigger sleds.