Panda 1

That's going to be a real minimum rocket !!!

While probably not necessary, since I am having to do a partial rebuild, I might as well make improvements.

Changes so far:

1. Increased overall height of tube portion of electronics bay by 10mm on top. This decreases the size of the coupler+bulkhead extension up into the nosecone thereby increasing the volume for the shock cord and drogue chute, making it a less tight fit. While the previous design caused no issues on the last flight, it made drogue chute packing tedious and accident prone.
2. Increased overall height of tube portion of electronics bay by 18mm on bottom. When the nose deployed early, this was the failure point separating the rocket into two pieces. I know that all is probably fine with this joint, but if I'm rebuilding it, having some extra surface area for the coupler/bulkhead increases structure strength tremendously.
3. I'm currently testing building the interior print shell using carbon fiber PC rather than PLA2. To properly test, I have to make sure there is no loss of radio signal since it does contain carbon fibers. I've already tested the 900MHz and bluetooth passing through and it exhibited no loss in signal strength. Next I need to test GPS reception and cell signal strength to insure there is no loss. If these tests prove successful, while I had no problems with strength of bay, the bay will be significantly stronger and lighter. I'll still wrap it in a few layers of 2oz glass on the outside, and a few strips of glass on the interior surface making it a nice sandwich. Sandwiching 3d print significantly increases the lifespan of the 3d print as joints have additional bonding by the glass and can't separate over time.
4. Lower coupler and bulkhead has been increased in thickness by 1.5mm and is now a min. thickness of 3.5mm. Top of coupler reaches into bay piece by 8mm more for a total of 22mm. Bulkhead has been moved down 16mm allowing for more storage of wiring. Total coupler length is now 7cm.
5. I'll create a kevlar loop around the electronics bay with the intent to keep the entire rocket together. This is the first rocket where I did not do this due to strength in bay and coupler/bulkhead components.

Finally got back to the improvements. Almost ready for primer.

See previous post for details of improvements. I was able to use carbon fiber poly-carbonate as testing GPS/Cell/900MHz all passed with flying colors. The density of carbon fiber is not high enough to inhibit signal strength.

The specific brand I am using for CF PC is strong and has fairly detailed specifications: https://www.3dxtech.com/product/carbonx-pc-cf/

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The left half is 5.7oz/sq yd solid carbon fiber twill rolled laminations as it is just body tube. The CF is sandwiched on both sides by a wrap of 2oz fiberglass to smooth & make it easier to work with.

The right half is printed CF PC wrapped twice in 2oz/sq yd fiberglass.

Powerful deployment in your video.

For me, that is the ideal amount of power and what I try to achieve during testing. My thought process for good punch is, less chance for complications caused during part separation inhibiting full ejection.

frewi80 on 2021-11-15 17:51:46Z wrote:

Powerful deployment in your video.