Shortening An Aerotech Delay Grain

[Uncrichie]

I believe at one time I saw mention of a way to partially drill an Aerotech delay grain to reduce the timing? I have several 29mm reloads with medium delays. I need to shorten them to 5-6 seconds. Is there info anywhere I can tap into? Also does anyone know the drill size to use? Thanks in advance. Uncrichie.

 

[mikeyd]

Try this
https://www.aerotech-rocketry.com/c...tions/RDK_Instructions/rms_delay_mod_inst.pdf

 

[billspad]

Try this.

 

[billspad]

You beat me in the two minutes it took me to find it on the Aerotech site!

 

[mikeyd]

You beat me in the two minutes it took me to find it on the Aerotech site!

I am normally the one that is just behind, so I understand your pain.

 

[Uncrichie]

Thanks everyone. I can't believe that this got wrapped up in 10 minutes. Its ironic that the example given in their instructions is the exact amount I need to reduce the delays, .094". Thanks again. Uncrichie

 

[Zeus-cat]

Thanks everyone. I can't believe that this got wrapped up in 10 minutes. Its ironic that the example given in their instructions is the exact amount I need to reduce the delays, .094". Thanks again. Uncrichie

Can you let us know how well it works?

 

[rcktnut]

I've been shortening Aerotech delays for years using their DDA, it works great!!

 

[tomar]

I wonder if the same 1/32 inch per second calculation works for the CTI motors. If so, I'll use this method on the Pro38 and Pro29 delays since I often need delays inbetween the stops on the DAT.

 

[Uncrichie]

Can you let us know how well it works?

Will do.

 

[bobkrech]

I wonder if the same 1/32 inch per second calculation works for the CTI motors. If so, I'll use this method on the Pro38 and Pro29 delays since I often need delays inbetween the stops on the DAT.

Tomar

Follow the manufacturer's recommended method of shortening the delay on your CTI motors. The PRO DAT reduces the maximum delay by -3, -5, -7, and -9 seconds. NFPA 1125 allows a variation in a manufacturers specified delay of +/- 1.5 seconds for up to a 7.5 second delay, and +/- 20% to a maximum of 3 seconds for longer delays, so your reason to use an unauthorized method of delay shortening doesn't make sense. Furthermore the CTI delays are the most accurate in the hobby, and are much better than the NFPA requirement so there's no need for an alternative tool or method.

Bob

 

[tomar]

Tomar

Follow the manufacturer's recommended method of shortening the delay on your CTI motors. The PRO DAT reduces the maximum delay by -3, -5, -7, and -9 seconds. NFPA 1125 allows a variation in a manufacturers specified delay of +/- 1.5 seconds for up to a 7.5 second delay, and +/- 20% to a maximum of 3 seconds for longer delays, so your reason to use an unauthorized method of delay shortening doesn't make sense. Furthermore the CTI delays are the most accurate in the hobby, and are much better than the NFPA requirement so there's no need for an alternative tool or method.

Bob

I forgot that CTI only recommends the use of their Pro DAT to shorten the delay grains where as AT has the recommended method describes previously. It has been my experience that the CTI delay grains are very accurate. I've only had one delay failure with CTI motors since they started shipping the Pro 38 motors. I can't say the same for the AT delays (this is one reason I use electronics for AT motors).