Satellite Interceptor Build 2

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I recalled from another thread someone posting about papering plywood fins. Most people felt it wasn't required. But after priming, I found a lot of the grain showing through. So I skimmed a layer of F&F and sanded it down. More primer tomorrow...

primeb.jpg
 
Finally decided to compromise and cut 3.5" off the tube.

Working the brass shear strips for the nose cone now - pix later (sorry)
 
Shear strips added to top

shimd.jpg

I originally had to sand the nose cone shoulder to allow it to fit. After adding the shear strips it was tight again. I must not have sanded the tube enough for the brass. So more sanding of the shoulder. A lot of the coating is now gone, but it is just on the shoulder.

cone sand.jpg

And another layer of prime on the bottom (which was greatly improved after the F&F) and some prime for the top

primec.jpg primetop.jpg
 
Latest status...

Epoxied bulkhead into the nosecone

Cone bulk.jpg

Unfortunately, while the epoxy was drying it fell over, dinging the cone paint. I also found some "pinholes" in the bondo seam fill.

So a little sanding, a touch more bondo

cone fix.jpg

And time for a hole count....

Holes for rail buttons - check

holea.jpg

Shear pin holes, altimeter vent hole (one of 3) - check

holeb.jpg

And nose cone shear pins and pressure relief hole - check

holec.jpg

Whoops - need a pressure relief hole for the main body
 
Sanded the bondo on the nose again and primed.

Decided I really need to do an ejection test.

The tube is 2.63 in diameter. The engine/fin section is 11" in length. Two 2-56 shear pins. Calculated 8 grains (my measurement tools are in grains, not grams)
Top section for main is 19" in length. Three shear pins. Calculated 18 grains.

Since the cone was only in primer, plus very pointy I decided to protect it with a combination of bubble wrap and craft sticks taped tot he wrap.

protect.jpg

Then there was the mayhem as I was selecting cords, chutes, etc...

mayhem.jpg

I made up some charges, Z folded/taped the cords, assembled the rocket and went out to test.

Apogee charge - wimpy. Rocket separated, chute came out but didn't break any of the taped Z folds. Probably need to boost it some

Main charge - :cry::cry::cry::cry::cry::cry::cry:
Probably says enough. Pushed the button on the controller....

destroyed.jpg

I did find 2 of the 3 shear pins did break, but...

:cry::cry::cry::cry::cry::cry::cry:

So - I don't see me getting this rocket done in time for LDRS :bang::bang::bang::bang::bang:

and it never got to fly...... I will try to get back to this after LDRS and hopefully be ready for URRF

More need to figure out why it happened and what I can do about it during the rebuild. I don't see adding a layer of FG as the main body/fins are all painted.
 
That sucks! Sorry for your loss....
 
I am thinking it is how I did my charges. Instead of a charge well, I take some plastic tubing. I check the ignitor continuity. Insert the ignitor into the tube and seal with a hot glue gun. Let cool. Insert BP into other end of tube. Pack extra space with dog barf. Multiple wraps of tape end to end. My bulkhead just has a bolt sticking out that I tape this tube to. Below is a picture of the apogee charge. You can see the tube split along the length. What I suspect is the main charge got pushed to the side by the laundry and against the body tube. When it let go, the blast may have been directed at the body tube causing the damage. The blue tape was what I secured the charge to the bolt.

IMG_2191.jpg
 
I am thinking it is how I did my charges. Instead of a charge well, I take some plastic tubing. I check the ignitor continuity. Insert the ignitor into the tube and seal with a hot glue gun. Let cool. Insert BP into other end of tube. Pack extra space with dog barf. Multiple wraps of tape end to end. My bulkhead just has a bolt sticking out that I tape this tube to. Below is a picture of the apogee charge. You can see the tube split along the length. What I suspect is the main charge got pushed to the side by the laundry and against the body tube. When it let go, the blast may have been directed at the body tube causing the damage. The blue tape was what I secured the charge to the bolt.

View attachment 315911

What type of plastic tubing? I'll bet you ran into a situation where the tubing contained the pressure long enough for all the BP to burn and then fractured leading to what amounts to a mini explosion inside the base. Have you considered moving to brass or copper tubing?

The shear pin that did not shear: was it elongated and deformed?
 
What type of plastic tubing? I'll bet you ran into a situation where the tubing contained the pressure long enough for all the BP to burn and then fractured leading to what amounts to a mini explosion inside the base. Have you considered moving to brass or copper tubing?

The shear pin that did not shear: was it elongated and deformed?

Are you suggesting a copper tube so it will be stronger and have the taped end blow out first?

I did not notice any deformation of the screw. I unscrewed it from the rocket without any problems

And the two that "sheared" - the heads sheared off but I had to drill them out as they were still securing the cone.
 
Are you suggesting a copper tube so it will be stronger and have the taped end blow out first?

I did not notice any deformation of the screw. I unscrewed it from the rocket without any problems

And the two that "sheared" - the heads sheared off but I had to drill them out as they were still securing the cone.

I am suggesting copper tubing will direct the charge better and the pressure buildup won't be as instantaneous as what you got with the rupture of the plastic tubing. It will be directed at the nose, which should help.
 
Back from LDRS...
Easter is over...
New tubes - didn't document filling the spirals, priming, painting

I did have to replace the coupler for the AV bay as I couldn't figure out how to easily line the holes back up for the shear pins (the existing holes would be in the coupler and I would need to drill holes in the body tube to line up).

I did drop down to 2 shear pins for the nose cone.

And while at LDRS I picked up something......

Charge wells!!! Hopefully this will keep me from blowing things up again...............

well.JPG
 
OK - been a bit

Partly afraid of blowing up the rocket again
Partly weather
Partly other life events

But - I blew up my rocket tonight without blowing up my rocket! :w:

Successful ejection test and body tubes in one piece!

Also spent time getting the stickershock vinyl on

IMG_2436.jpg IMG_2435.jpg IMG_2434.jpg IMG_2433.jpg IMG_2432.jpg
 
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