Launch Test 80

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This launch is just about a duplicate of Launch Test 79. The only change made was reducing the apogee deployment charge to 1.8 grams of BP rather than the 2.4 used in the prior launch.

Here is lift off.

Another nice straight flight.

Here is the rocket coming down under both chutes.

Another nice flight, and another good landing, but... Both chutes again came out at apogee. I'm confused.

When I got home I again tested the electronics, they were working perfectly. So why is the PIRM2 firing at apogee? I just sat and looked at the electronic module, thinking. Then I had an epiphany. So I did a test to confirm my hunch. What happens to the output of the main chute timer when the first timer times out, when they are both hooked up to the same power supply? Answer, it drops the battery voltage and the main chute timer senses that drop in voltage the same as if it had timed out and fires the PIRM2. Geez, that was simple, why hadn't I thought of that sooner!

So I rewired the electronics module with a single throw double pole switch, using separate batteries for apogee and main deployment charges. A quick retest confirmed all was again working as it should.

I prepped the rocket for another flight, the weather is supposed to be good again tomorrow.