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Bruce

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We're having difficulty with ignition of a D13W in an 18/20 case. We got the first one to light on the 2nd try. But the second one has gone thru 2 ignitors and still hasn't lit. Figured we must be doing something wrong.

We have triple checked and the ignitor is in the slot and is pushed ALL the way up to the top. The ignitor wire was secured with masking tape to keep it from moving down. Each time the ignitor and it's pyrogen burn without igniting the propellant.

I realize that this motor has a small nozzle throat diameter requiring the ignitor to be small with a limited amount of pyrogen. But we've had 100% ignition reliability on a dozen firings of our 24mm E6-RCT reload which has an even smaller nozzle.

Any suggestions or advice?
 

AeroTech

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We're having difficulty with ignition of a D13W in an 18/20 case. We got the first one to light on the 2nd try. But the second one has gone thru 2 ignitors and still hasn't lit. Figured we must be doing something wrong.

We have triple checked and the ignitor is in the slot and is pushed ALL the way up to the top. The ignitor wire was secured with masking tape to keep it from moving down. Each time the ignitor and it's pyrogen burn without igniting the propellant.

I realize that this motor has a small nozzle throat diameter requiring the ignitor to be small with a limited amount of pyrogen. But we've had 100% ignition reliability on a dozen firings of our 24mm E6-RCT reload which has an even smaller nozzle.

Any suggestions or advice?
Try roughing up the slot in the grain with a knife or fingernail file.
 

ghuber

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I'm not sure if this is the right thread to ask this on, but does anyone have experience with the M1340 and whether one can bond a hardpoint for recovery hardware into the forward bulkhead? (where a charge well would normally be located).

This thread has a great photo, as do the instructions, and it sure looks like a solid attachment point, but I'm not sure.


Thank you -Greg
 

tfish

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I'm not sure if this is the right thread to ask this on, but does anyone have experience with the M1340 and whether one can bond a hardpoint for recovery hardware into the forward bulkhead? (where a charge well would normally be located).

This thread has a great photo, as do the instructions, and it sure looks like a solid attachment point, but I'm not sure.


Thank you -Greg
The M1340 DMS motor comes with an aluminum Forward Closure that has a 3/8-16 threads built into it..

Tony
 

ghuber

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Mea culpa, I realize I mixed up the M1340 DMS (98mm) and the M1350 DMS (75mm). Is the M1350 the same in terms of having the threaded aluminum forward closure? Also, does anyone have experience using it for mounting recovery hardware? Thanks again.
 

AeroTech

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Mea culpa, I realize I mixed up the M1340 DMS (98mm) and the M1350 DMS (75mm). Is the M1350 the same in terms of having the threaded aluminum forward closure? Also, does anyone have experience using it for mounting recovery hardware? Thanks again.
Yes.
 

tfish

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Mea culpa, I realize I mixed up the M1340 DMS (98mm) and the M1350 DMS (75mm). Is the M1350 the same in terms of having the threaded aluminum forward closure? Also, does anyone have experience using it for mounting recovery hardware? Thanks again.
Using the threads on an aluminum Forward Closure is the strongest anchor point on our rockets. You still need to take some precautionary steps...

1. Retain the motor to keep if from falling out. Aft motor retainer or other retention or held in via those same threads to an internal bulkhead.
2. You also need to keep your attachment point Forged or welded eye bolt or eye nut..from unscrewing itself. Yes it CAN and DOES unscrew it self. Jam nuts or other restraining methods work.

20210421_083902.jpg


Tony
 

CarVac

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I just noticed the G71R for the 29/40-120 is out of production. Is that coming back? Maybe something more G138-style?
 

dhbarr

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Bet mine is more boring!!!! 412 west out of Tulsa is HORRID.......so much so, I’ve started going through south eastern KANSAS to get to Argonia.....!!!! 😳😁🤣😂
What did Sand Springs ever do to you? 🙃
 
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GlueckAuf

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I just noticed the G71R for the 29/40-120 is out of production. Is that coming back? Maybe something more G138-style?
The G71-xR RMS reload kit for the AT 29/120-40 hobby case has been out of production since circa 2018 I believe, withdrawn due to problems with the delay element's unreliable timing. There is still a single use version of the motor, the 29mm G77-xR. I'm unaware of any effort to replace the RMS version.

Good skies,
GlueckAuf
 

AeroTech

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The G71-xR RMS reload kit for the AT 29/120-40 hobby case has been out of production since circa 2018 I believe, withdrawn due to problems with the delay element's unreliable timing. There is still a single use version of the motor, the 29mm G77-xR. I'm unaware of any effort to replace the RMS version.

Good skies,
GlueckAuf
Karl has been working on and off on a core burning version of the G71R. No timeline for certification yet.
 

Theory

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Would really like a single grain bates red for the 40-120 case.

huge fan of the G138. The red wouldn’t be as punchy for sure, but would be an awesome load!
 

mtnmanak

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I have a K2050 I plan on using this weekend. I opened the kit today to do the grain bonding. I realize the Aerotech grain bonding instructions are generic, but they do mention putting a grain spacer o-ring between each grain. This reload kit didn't come with grain spacer o-rings. Am I missing them or this reload supposed to not have them?
 

mtnmanak

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I may have answered my own question, when I dry fit the grains, they are actually too long. No way o-rings would fit between them. Even without o-rings, the forward seal disc doesn't seat into the liner. the grains come right to the end of the liner.

So, I guess second questions would be, assuming there are not supposed to be grain spacer o-rings, can I sand the end of one of the grains to get the forward seal disc to fit?
 

jd2cylman

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I may have answered my own question, when I dry fit the grains, they are actually too long. No way o-rings would fit between them. Even without o-rings, the forward seal disc doesn't seat into the liner. the grains come right to the end of the liner.

So, I guess second questions would be, assuming there are not supposed to be grain spacer o-rings, can I sand the end of one of the grains to get the forward seal disc to fit?
Yup
 

DigBaddy

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This may have been discussed earlier...and I didn't search too hard. NAR magazine shows the new 24mm QJets on the back and I like what I see. I expect to burn a pile of them when I can get some. Those are White Lightning propellant, so are there some with Black Jack propellant, like the 18mm QJets, on the way with a little less kick and longer burn time?
 

AeroTech

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This may have been discussed earlier...and I didn't search too hard. NAR magazine shows the new 24mm QJets on the back and I like what I see. I expect to burn a pile of them when I can get some. Those are White Lightning propellant, so are there some with Black Jack propellant, like the 18mm QJets, on the way with a little less kick and longer burn time?
Not yet on the way but those are certainly a future possibility.
 
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