AT 29/40-120 delay adjustment.

[Bat-mite]

Yes, I use the delay tool that came with my Cesaroni motor set, only because...it's there.

I thought of making a similar tool for my Aerotech stuff , but have just got accustomed to just a drill bit and an eye ball or two.

Are they compatible? I have a CTI delay tool.

 

[rharshberger]

Are they compatible? I have a CTI delay tool.

iirc there used to be a delay adapter so you could drill AT delays with the CTI DAT tool.

 

[grouch]

If you need an excuse to buy the AT tool, they work great on Loki delays as well.

 

[Bat-mite]

Got a cheap 29/40-120 case on eBay, and ordered 10 G76-7 Mojave Greens from Wildman. Should have everything tomorrow or Wednesday. My current line of thought is that if 5 sec. is prime delay, a 7-sec delay is not so bad. So if I just drill a tiny bit out and get it down to 6 sec., I think I'll be good with that. Or, maybe I will figure out how to adapt the CTI drill. Or, maybe I will just ask somebody at the launch site.

 

[Oberon]

I mean, at $17 from Sirius, not getting the right drill tool seems kind of penny wise pound foolish. If it saves you from one zipper or damaged chute from a mistimed delay... Heck, you can buy the tool and a reload from Wildman for basically the cost of one HAZMAT charge!

The other nice thing is that the aerotech drill works with all their rms loads from 18-38mm, so now that you've bit the AT bullet you can grab the very nice 24/40 case as well, which is a brilliant little motor, especially for Estes kits that are a bit wimpy on D12s (I've got a mean machine kit back from before they came with a longer engine mount to accommodate high thrust Es, and it flies beautifully on the E18 RMS).

One issue you'll have with the CTI drill is that I believe the RMS delay grain is quite a bit narrower than the CTI, and the drill bit on the CTI is also fatter. So you might have trouble drilling the grain without hitting the sides if you're even a little off-center, which might be bad news.

 

[Bat-mite]

I mean, at $17 from Sirius, not getting the right drill tool seems kind of penny wise pound foolish. If it saves you from one zipper or damaged chute from a mistimed delay... Heck, you can buy the tool and a reload from Wildman for basically the cost of one HAZMAT charge!

The other nice thing is that the aerotech drill works with all their rms loads from 18-38mm, so now that you've bit the AT bullet you can grab the very nice 24/40 case as well, which is a brilliant little motor, especially for Estes kits that are a bit wimpy on D12s (I've got a mean machine kit back from before they came with a longer engine mount to accommodate high thrust Es, and it flies beautifully on the E18 RMS).

One issue you'll have with the CTI drill is that I believe the RMS delay grain is quite a bit narrower than the CTI, and the drill bit on the CTI is also fatter. So you might have trouble drilling the grain without hitting the sides if you're even a little off-center, which might be bad news.

Thanks. I appreciate your comments. However, I have no plans to expand my Aerotech motor collection beyond the 29/40-120. They will only be for my G-Force, which is old. Once that rocket gets retired, I will be all CTI. I only got into that boat because I built my GF stock before I knew anything about reloads and HPR.

I am very loyal to AMW-ProX. They have been very good to me, and I will be a CTI man until the day they stop attending MDRA launches. No offense intended to AT or AT users.

If I have to stick with 7, it will be just like flying an SU motor, where your choices are 4 or 7.

 

[kcobbva]

So from what I gather, the supplied washer is 1/16" and takes off 2 seconds of time. If I were to add a 1/32" washer along with the 1/16" supplied, then theoretically on a 10 second delay, using the 8-second slot, i could get a 5 second delay drilled out. Sound about right? Granted I'm sure there may be a little play, but I'm looking for a 5 second delay in a G76-10 for an older scratch build I built 12 years ago. Thanks.

 

[kevinkal]

So from what I gather, the supplied washer is 1/16" and takes off 2 seconds of time. If I were to add a 1/32" washer along with the 1/16" supplied, then theoretically on a 10 second delay, using the 8-second slot, i could get a 5 second delay drilled out. Sound about right? Granted I'm sure there may be a little play, but I'm looking for a 5 second delay in a G76-10 for an older scratch build I built 12 years ago. Thanks.

That sounds correct to me.
Put the delay into the deepest hole: -8 seconds
Install the 1/16" washer: +2 seconds
Install a 1/32" washer: +1 second
Add up resulting delay: 5 second final delay

Aside, I checked the stock AT RMS Plus Delay tool washer.. it was 0.0595" on the digital caliper... so not quite 1/16".

 

[Rex R]

that is how I have my tool set up, a one second washer(that I made from some brass sheet), and the supplied 2 second washer to get an adjustment range from 1 to 3 seconds.
Rex

 

[Daddyisabar]

I know of a guy who just hacks them with an Exacto knife. Each motor type and delay burns a little different and with experience he says you can get real close. Many successful flights on G76,64 and 53's. Same for 24mm. I even saw him fly his silly Sunward Umbrella many times on an F12 with cut down short delays. That rocket needs lots of power but basically needs no delay and yet have an ejection charge. I told him his silly odd rocs and lousy technique would catch up with him some day, and it eventually did. Up it went then a very early ejection, fell back to the ground next to the pad, landing upward with a flame and tons of black soot shooting out the top. Took quite a while to fully burn off, like a candle in the wind, the horror. Luck guy just got a fried upper tube and burned shock cord. His 24mm case was real sooty but the forward closure hole was still fine. He was back again the next launch flying it on a D12 3 which was just about as scary as his RMS blow-by then slow burn.