Best Way To Achieve Needed Delay

[JLP1]

I need a few ideas on how to achieve the desired delay on an Aerotech H148R-14A. It came with a 14 second delay element but my sims tell me that I need 9 seconds. The RMS Delay tool will give me either 10 seconds or 6 seconds if I use the 1/16 thick washer it will give me 2 seconds back making it 8 seconds. But for the best deployment I need between 8.80 and 9 seconds. I was thinking about adding a 1/32" shim under the washer but since this is my first foray into adjusting delays I wasn't sure if that would work. I know there are some +/- variance in the delay times so it may not be an issue. But if I go with 8 it could be 7 or 9 and if I go with 10 it could be 9 or 11.

This is going into a 3 1/2 lb. LOC IV and Rocksim says about 1800 feet which puts in an attitude that I'm comfortable with.

So I throw it out there for discussion

Thanks

 

[tsmith1315]

I know there are some +/- variance in the delay times so it may not be an issue.

Correct. +/- 20% or 1.5s, up to 3s, so anything within a second or two is considered accurate. You're drilling into rubbery stuff, it's not going to be a well finished hole in there. 1/32" adjustment is probably pushing the limits of the adjustment technique.

But for the best deployment I need between 8.80 and 9 seconds.

Is the sim that accurate in predicting real world time between burnout and apogee with variations in drag, actual motor thrust, final mass, environmental conditions, etc.?

Personally, I'd just err on the other side of apogee and adjust to 10 seconds. Plenty other things to worry about.

Do what makes you feel best, don't sweat over it, and move on. Enjoy the flight!

 

[tfish]

If any wind..drill it to 8 sec
No wind..drill for 10 sec

Tony

 

[SolarYellow]

https://eggtimerrocketry.com/apogee_faqs/