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  1. #1
    Join Date
    20th June 2015
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    Nosecone Tracker AVbay Questions

    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:

    Click image for larger version. 

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    Thanks for any advice - Jim

    Jim V

    Champlain Region Model Rocket Club
    CRMRC
    Facebook
    NAR #101467
    L1 - 5/21/16 Estes Mega Der Red Max H128W to 1,021'


  2. #2
    Join Date
    22nd August 2015
    Location
    Rhode Island
    Posts
    860
    (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.

    NAR #100940, RIMRA & CMASS
    L1 - 4/17/16, Tyrannosaur (by Binder Design), Loki H144
    Dual Deploy - 11/12/16, Tyrannosaur + Eggtimer TRS, Loki I405

  3. #3
    Join Date
    13th October 2014
    Location
    SouthEastern, WA
    Posts
    5,047
    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.
    Rich

    NAR# 99154

    L3-4x upscale Estes Cherokee-D- AT M1297W 5/28/2016 http://www.rocketryforum.com/showthr...r-rharshberger

    TriCities Rocketeers NAR section# 736 http://www.tricitiesrocketeers.org/

  4. #4
    Join Date
    7th July 2013
    Posts
    2,760
    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.

    Attachment 309004Attachment 309005Attachment 309006Attachment 309007Attachment 309008Attachment 309009Attachment 309010Attachment 309011Attachment 309012Attachment 309013
    Michael Pitfield
    TRA 14579 L2
    NAPAS, URRG, MARS, CRC

  5. #5
    Join Date
    5th December 2013
    Location
    MD
    Posts
    5,794
    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.
    John S. ---- NAR #96911 ---- TRA #15253 ---- MDRA #067 ---- BARC #028
    L1, 3/15/14: Aerotech Sumo, CTI H133BS
    L2, 6/21/14: Giant Leap Vertical Assault, CTI J240RL
    L3, 3/12/16: MAC Performance Radial Flyer, CTI M1101WH
    Altitude: 13,028', L3 flight; Speed: Mach ???, L3 flight

  6. #6
    Join Date
    13th February 2016
    Location
    Gilroy, CA
    Posts
    467
    Quote Originally Posted by smugglervt View Post
    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.
    http://www.rocketryforum.com/showthr...69#post1575869
    Kevin NAR, Section #534 LUNAR / TRA
    L2- Madcow Level-2 4" Fiberglass, Redundant DD
    Work in-progress: Madcow 4-inch Fiberglass Frenzy XL

  7. #7
    Join Date
    20th June 2015
    Location
    Vermont
    Posts
    320
    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

    Jim V

    Champlain Region Model Rocket Club
    CRMRC
    Facebook
    NAR #101467
    L1 - 5/21/16 Estes Mega Der Red Max H128W to 1,021'


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