Fine Tuning AT High Power RMS reloads with the RDK delay system

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Fore Check

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I think I remember a discussion along these subject lines previously around here, but I can't find anything with a search query.

Anyway - regarding the RDK delays for the AT "high powered" RMS reloads.

With these reloads (at least in 29 and 38mm), the standard delay is "M" which is defined as 10 seconds. The RDK delay packages are available to allow the flyer to purchase either a "S" (short) delay of 6 seconds or a "L" (long) delay of 14 seconds.

The RDK delay reference chart from AT is available here: https://www.aerotech-rocketry.com/c...Flyers_Data_Sheets/aeroTech_delay_lengths.pdf


For instance, at the last club launch I went to, I flew a G54W reload in my 29/100 case. I swapped the delay element that came with the reload packaging by purchasing a pack of RDK-3 delays to make it a short (6 sec) delay. Worked great. (see page 2 of that reference PDF.)

Staying on p2 of that reference PDF, I was looking at the delay choices for the H165R in the 29/180 case and I got to thinking. AT gives you 3 recommended delay choices for that (and most others, only 2 in some) reload(s). Can you do the math to come up with delays that would fill the 4 second gaps (between 6, 10, and 14 in this example) to get a more "finely tuned" delay matrix for a given reload - similar to "drilling" delays on other reloads?

Looking at the H165R reload still, let me start by filling in that 4 second gap going shorter first.

According to the chart:

H165R - M = 0.500" delay length = RDK 18
H165R - S = 0.375" delay length = RDK 02

0.500 - 0.375 = 0.125" shorter for 4 seconds
0.125 / 4 = 0.03125" per second of shorter delay

0.500 - (1 x 0.03125) = 0.46875 ~= 0.469 = RDK 04 (9 sec. delay)
0.500 - (2 x 0.03125) = 0.4375 ~= 0.438 = RDK 03 (8 sec. delay)
0.500 - (3 x 0.03125) = 0.40625 ~= 0.406 = RDK 09 (7 sec. delay)
0.500 - (4 x 0.03125) = 0.375 = RDK 02 (6 sec. delay)
0.500 - (5 x 0.03125) = 0.34375 ~= 0.344 (no RDK available for 5 sec. delay)
0.500 - (6 x 0.03125) = 0.3125 ~= 0.314 = RDK 01 (4 sec. delay)

Is this making sense? Am I on the right track?

Going longer now to fill in between the "M" and "L" delays:

H165R - M = 0.500" delay length = RDK 18
H165R - L = 0.594" delay length = RDK 06

0.594 - 0.500 = 0.094" longer for additional 4 seconds
0.094 / 4 = 0.0235" per second of longer delay

Looking at the chart, I can only find two delays in length between the RDK 18 and the RDK 06.

RDK 17 = 0.531"
(0.531 - 0.500) / (0.0235" per sec) = 1.32 sec additional
So, for RDK 17, delay would be: 10 + 1.32 = 11.32 sec delay

RDK 05 = 0.563"
(0.563 - 0.500) / (0.0235" per sec) = 2.68 sec additional
So, for RDK 05, delay would be: 10 + 2.68 = 12.68 sec delay

If this "logic" and/or math is correct, you could continue this process for other delays beyond 14 seconds if you wanted.


For other reloads, you could change the base delay lengths (for M, S, and L respectively) and get even expanded delay combos for them.

Again, assuming that this is correct thinking.

I'm hoping that someone would chime in here and correct me if I am off base with this.

Thanks!
 
You engineers - always trying to outsmart the manufacturer. :D

I'm far from an expert and will only say I believe that the delays burn differently and at different rates depending on the motor propellant. Mostly due to internal pressure from what I've read.

Keep it simple and get a DAT for adjusting delays by drilling. AT approves of this so it's 'legal.'

dat003.jpg
 
Originally posted by Fore Check
I think I remember a discussion along these subject lines previously around here, but I can't find anything with a search query.....

Again, assuming that this is correct thinking.

I'm hoping that someone would chime in here and correct me if I am off base with this.

Thanks!
It's not "approved" but basically correct.

See https://www.rocstock.org/wizards.html Motor info.

Bob
 
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