Resurrecting The Black Dahlia

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Bill,

Thank you for the tips. After reading your post, I went back to see what I could do to the current design to shed some weight, and I believe I have a minor fix. Based on how I designed this sled set-up, I can remove a good bit of the all thread as pictured (remove all-thread from inside the boxed region). My only concern would be deployment force being transferred to the sled plate itself, instead of being fully absorbed by the all-thread.

IMG_8673_all-thread_removal_zpsg2jzt5wk.jpg
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I agree this would put way to much strain on the board and I would Not do that.. I will try to get some pictures of one of my other Av bays to give you a better picture of what I am thinking about.
 
I have opted to stay the course for the moment. The SkyRipper J motors should be adequate to get the rocket up safely and high... but dual altimeters may have been a bit of over kill for the project. The next 4" project in line is a Retro Binder Design Raptor. I will try to use "lighter" methods of building that rocket and avionics.
 
I have finished the sled and bulkhead of the avionics, just short of adding two screw switches, which I will construct mounts for this weekend. Here are images of the avionics as they currently sit:

zPOKX2t.jpg


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Good looking av-bay!

Not bad! Looks pretty good if you ask me.

Thanks; this av project has taken me a while to complete... but has only come together just recently. Once I get the screw switches in I will build up some mounts from ply or balsa and get the bay finished up. Then it is onto sanding and prepping for prime & paint.
 
Small update to this rebuild; the airframe has gone to primer, which has indicated that there is much to be done in the beauty department... not the best fiber glass job I have ever done, as hundreds of little air holes have been high lighted by the primer application. Off to get more primer now.

jd82GKU.jpg
 
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I am considering lopping off the fin tips and going with a more trapezoidal fin design. Would any think this a bad move at this stage of the rebuild?
 
Last nights work was actually a step backward, as I dismantled the avionics for this rocket. The avionics was way over-built and was getting to heavy. From the components I will be able to outfit two rockets with complete avionics, including wiring and Blast Cap ejection wells. I will get back to the final avionics config once I have re-evaluated what is left over, and how I can best cut excess weight.

I have decided not to cut the fins into a trapezoidal shape.
 
So while working on a weight budget for this project, I decided that the avionics had to shed some weight. Redundant altimeters was a bit much for a low end J-class hybrid rocket. I dismantled the avionics that I designed for this project, and was able to build two complete avionics packages, one for this rocket, and one for the Excalibur... another low end J-class hybrid rocket. Here is the new layout for the Black Dahlia using a little more of the K.I.S.S. concept...

J1OOpZ3.jpg


I am still using hardware to assemble, rather than epoxy... looks cleaner to me...

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The change has cut the weight of the avionics in half or more...
 
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Minor update to the avionics; I cut the switch hole, the vent holes and the threaded insert holes. And mounted the threaded inserts...

wbrHp6V.jpg


Tomorrow I hope to sand the airframe down and get another filler coat of primer on, in hope to get paint on next weekend.
 
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Nice work on both builds, and glad to have you back again. Once you get the rockets completed, where are you going to launch them?
 
Nice work on both builds, and glad to have you back again. Once you get the rockets completed, where are you going to launch them?

Thank you, I appreciate that, it has been quite fun working with these two rockets again. I just re-upped with PMW, and hope to launch this fall and winter flying season. My daughter's marching band season will dictate which launches I can make through November, then I am open there after. My daughter wants to build an Aerotech Mirage and come fly with me.
 
Since I have a 'snow day' from work, I thought I would replace all of the images in this thread that photo bucket locked me out of.

Another ebay change has been added to the build, and that is to replace the wood sled (add associated hardware) with a 3D printed sled from Additive Aerospace. A sled originally designed for 76mm airframe ebays works like a champ in this build:

svcpVnx.jpg


Hope to get this resurrection done this Spring...
 
Finally bringing this rocket back to flight status; recovery is finished and installed, electonics are installed and ready for some clear (& dry) weather for deployment ground testing. Today my wife and I installed the graphics that I purchased through Stickershock21:

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Although I called the rocket The Black Dahlia, I have sense gone back to the original profile (envelope) of the original design. Once the clear coat is applied, I will get a full up pic.
 
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