Nosecone Tracker AVbay Questions

[smugglervt]

I've built two nosecone avbays for my Estes MDRM and Binder Design Thug, both 4" with plastic nosecones. I used the John Croker method for constructing the nosecone avbays. I'm now getting ready to start my 4" FG Patriot and want to do a nosecone avbay for this one as well. My concerns are how to attach the bulk plates so they are secure enough without having a lip like with the plastic nosecones. I was thinking of epoxying a 3/8" plywood bulkhead into the nosecone couple, to which the G10 bulk plate and sled would be attached with T-nuts. My concern is whether this setup would be strong enough considering there is no lip like in the plastic nosecones to add strength to the bonding. Is epoxy enough or should I consider countersinking screws through the coupler and into the plywood bulkhead for added support? This will hopefully be my L2 bird and I'm just trying to get my ducks in a row before I commit to the build.

Here's my MDRM setup:



Thanks for any advice - Jim

 

[BDB]

(Disclaimer: I've never done this, so take my recommendation with a grain of salt.) It seems to me that you could epoxy something like the ring shown above containing the threaded inserts half way up the NC coupler; then you could epoxy a custom-made coupler behind it--effectively making a lip like in the plastic nosecones.

 

[rharshberger]

You can also use #2 brass wood screws through the nosecone wall into the wood ring, then sand the screws to match the nose cone shape. Combined with epoxy it should be plenty strong.

 

[mpitfield]

Most of my HPR rockets have AV bays, primarily for tracking although some are also altimeter and tracking. I also use John's method.

In some cases, with plastic nosecones, I have inserted a ply ring inside and above the nosecone which is easy because you can squeeze the nosecone out of round insert then just flip the ring horizontal above the shoulder. I have also epoxied the same type of ring, but G10 onto the top of the G10 coupler before I epoxied it in to the FW/FG nosecone. In both cases the ring has 2-3 PEM nuts epoxied into the ring that line up with the nosecone bulkhead. I have also done the latter but instead of epoxying the G10 ring/coupler into the FW/FG nosecone I made it removable for servicing, with three machine screws countersunk into the nosecone 120 degrees apart that also screw into PEM nuts, and this works really well.

I did this on my 54mm CF MD Tomach and the benefit is I can walk up to the pad get everything loaded, pull off the nosecone, but not disturb my packed recovery system, because the couple stays in place with my shear pins, turn on my trackers then screw my nosecone in place. Below are two examples.

View attachment 309004 View attachment 309005 View attachment 309006 View attachment 309007 View attachment 309008 View attachment 309009 View attachment 309010 View attachment 309011 View attachment 309012 View attachment 309013

 

[Bat-mite]

Here's a thought out of left field for you, and NOT a direct answer to your question.

What I do with polystyrene nose cones and a BRB900 transmitter is this: cut a window in the shoulder of the NC; shove my transmitter in a piece of foam pipe insulation cut to the size of the NC; shove the insulation and transmitter into the NC; tape over the hole with one or two pieces of masking tape.

Don't forget to turn on the transmitter before you shove it in. Using this method, no AV bay is needed. There's no metal threaded rod to interfere with the signal, etc.

 

[kevinkal]

I've built two nosecone avbays for my Estes MDRM and Binder Design Thug, both 4" with plastic nosecones. I used the John Croker method for constructing the nosecone avbays. I'm now getting ready to start my 4" FG Patriot and want to do a nosecone avbay for this one as well. My concerns are how to attach the bulk plates so they are secure enough without having a lip like with the plastic nosecones. I was thinking of epoxying a 3/8" plywood bulkhead into the nosecone couple, to which the G10 bulk plate and sled would be attached with T-nuts. My concern is whether this setup would be strong enough considering there is no lip like in the plastic nosecones to add strength to the bonding. Is epoxy enough or should I consider countersinking screws through the coupler and into the plywood bulkhead for added support? This will hopefully be my L2 bird and I'm just trying to get my ducks in a row before I commit to the build.

I had good results using high strength epoxy to bond in a bulkhead mounting ring. The link below is to the page with the first few pictures.. later in the thread I posed pictures of how I mounted an EggFinder tracker to a sled in the nose. I'm planning to use the same method in my current 4" FG build too.
https://www.rocketryforum.com/showt...s-Airframe-w-54mm-Motor&p=1575869#post1575869

 

[smugglervt]

Thanks everyone for the advice. I've decided to go with the 3/8" ring epoxied in with a couple of brass screws through the coupler into the ring. I think with a good fillet of Rocketpoxy and the brass screws it should hold well. I've ordered a 54mm FG sled from Wildman that I'll attach to the stock G10 bulkhead with a short section of 54mm tubing and screw this to the ring with T-nuts. I haven't decided if I'll do a build thread since it's going to be a pretty stock build except for the nosecone.

Thanks again for the responses.

Jim