LOC Forte av-bay...

[Mugs914]

Got my L1 cert back in August with this bird using motor ejection, but always intended to set it up for DD. I figured it would be great for getting up to speed with the electronics.

The cert flight was made with the av-bay empty, this is the sled I built for it.

The basic sled is a LOC kit. I went with Missileworks altimeters for primary (RRC3) and backup(RRC2). I wanted to go with an RRC3 and a Stratologger to get experience with two different types of altimeter at the same time, but Stratologgers seem to be harder to get a hold of than clear pictures of Bigfoot. I will get one eventually!

The drogue side bulkhead has the two terminal blocks, but no charge cups. The pics don't show them, but I added two small screw eyes so I can tie the ends of the e-match leads to them and drop the actual charges down the tube before the chute and harness bundle. The stuffer tube in the booster doesn't leave a super deep space.

The main bulkhead is set up with the CPVC charge wells. It will be prepped in the normal manner with the charges retained in the cups. The problem with the main chute payload bay is space, or lack thereof... I'm going to have to cut part of the shoulder off of the nosecone and use the space to pack the harness. A thin mil X-form chute packs up pretty small, so I should be okay. Worst case I use a longer piece of tube for the main.

I went with screw switches for both altimeters. The RRC3 switch connection is jumpered and the switch actually interrupts the battery circuit. I'm going with 9v batteries on this one, so I built appropriate mounts on the back side of the sled as well as mounts for the screw switches. Both are made from basswood. The 9vs will be retained by zip ties wrapped around their vertical axis.

Still left to do is to drill the wing nuts for safety wire and replace the eyebolts with forged (or weld these up), and of course charge testing.

Here are a few pics. Please feel free to comment, this will be my first DD attempt (Hopefully at the January AARG launch) and any advise is appreciated!



Backside...


Switches...



Drogue end (Screw eyes not installed yet)


Main end (Looks like I startled it...)

 

[blackjack2564]

Very nice work.
Just a couple suggestions based on my experience.
I always do a wrap or 2 of electrical tape around the snap-on connector, and battery.
If something goes violently bad they will stay connected, as in apogee event or cato. Both have happened and the wrap saved the day.

Those screw switches can vibrate loose during transport.[3hr drive] I was very po'd after using 3 of them for 2 altimeters and a GPS. When I got to pads all 3 had fallen into av-bay.
Cured it with a bit of sticky tac under head to keep in place. Just a heads up on that, I am not the only one had had issues.Some use a file and burr threads sticking out back so they cannot come out.
Good luck with your L-2 attempt!

Ps would it be a safe bet that you have used safety wire for something...lol very neat job!

 

[David Schwantz]

I like to secure the batteries to the board with 2 tie wraps around the short side and one around the lengthwise so that they will not slide out.

 

[MikeyDSlagle]

Not sure I understand how the drogue side works. You are zip tying ematches to eye bolts and are going to drop charges in?
No charge wells? Which is fine but how will you insure the charges are up against the ematch and don't set one another off?I
Or am I missing something?

 

[David Schwantz]

I use little plastic vials. BP goes in them with e match, lid closes and it get 2 wraps of tape.

 

[MikeyDSlagle]

I use little plastic vials. BP goes in them with e match, lid closes and it get 2 wraps of tape.

I was directing my last response to the OP:

, but I added two small screw eyes so I can tie the ends of the e-match leads to them and drop the actual charges down the tube before the chute and harness bundle

I'm picturing him dropping two small charges down the tube and cramming the laundry down behind it. Just hoping that isn't the case.