29/40-120 HDK Chart : AKA g76 Is The Best

[dhbarr]

There, that title ought to be :hot: inflammatory :hot: enough.

		15	16	24	25	17	18	19	20	XX	21	YY	ZZ	22	23
E16W	2.0							4			7
E23T	1.6	5				8
F22J	3.3													5	7
F40W	2.1							4			7			10
F52T	1.4		5			8	11
G33J	4.4													5	7
G53FJ	1.7			5		7			10
G64W	2.1						4		7		10
G71R	1.5					4			7		10
G76G	1.5	4			7			10
G138T	1.1										14
		0.375	0.406	0.438	0.469	0.500	0.531	0.562	0.593	0.625	0.657	0.688	0.719	0.750	s.750

The 29/40-120 delay sequences had been nagging at the back of my mind for a while, and this weekend it all finally lined up.

As far as I know, this should be all of the reload and delay options ever offered for this case. g33 & g71 are OOP, and g138 requires an L1 cert in the US.

It seems apparent that a g76 with an hdk20 would be about an 11 sec delay ; hdkXX could be drilled from hdk21 ( 13-14ish? ) , hdkYY and hdkZZ from hdk22.

Hope this helps someone out! Remember that changing out the delay element makes it an EX load, but drilling per manufacturer's recommendations does not.

I wouldn't be surprised to see AT offering fewer HDKs in the near future, and further emphasizing the DDT.

Bonus: if you're using electronic deployment, the hdk22 and especially hdk23 should put out tracking smoke for a lot longer ; may hibachi the forward closure and/or other components though.

 

[Tonimus]

In regards to the bonus, if AT uses a 14 second delay in a G138 with a 1.1 second burn time, you should be safe with any total delay burn (including motor burn) under 15 seconds.

 

[dhbarr]

In regards to the bonus, if AT uses a 14 second delay in a G138 with a 1.1 second burn time, you should be safe with any total delay burn (including motor burn) under 15 seconds.

As Rex R reminds us on the other thread, the burn rate of the delay element during the thrust phase is dependent on the chamber temperature and pressure. g76 w/ hdk21 is going to be about 13s, hdk22 around 16s.

The only wild card is any use & drilling of the slow.750 hdk23. You'd have to remove somewhat less than 1/32" per second, and we have no characterization other than two relatively low pressure long burning loads.

Edit: I picked it up on a re-read. As long as your total doesn't exceed 14-15s, you shouldn't cook your case. Great observation!

 

[MikeyR.Saginaw]

Lined up, except the table doesn't line up on my iPad. Any way to get a PDF?

 

[dhbarr]

dhbarr's hdk research : final

 

[emckee]

what's the difference between HDK 22 and 23? The bottom row (which I assume to be delay length) lists the first as 0.750 and the second as s.750... What's the "s" mean?

 

[dhbarr]

AT has a 'standard' composition and a 'slow' composition. Not enough data points to extrapolate how slow is slow, but at a guess it's a similar burn rate at standard temperature and pressure, slower at low motor pressure.