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pellets in big cesaroni motors

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watermelonman

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Recently I saw someone fly a 98mm Cesaroni motor, with the big fat pyrogen coated ignitor, and claimed there was a pyrodex pellet in the top. No way, right? I figure they should know since they built it, but my experience says you only get either the pellet or the dipped ignitor, not both. Certainly none of the 75mm motors I have flown have had any pellets.
 

timbucktoo

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It's possible it was an AT motor in the case, no?
 

rharshberger

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Who says it wasn't a homebrew igniter. Since 75mm and up Cesaronis dont use ignition pellets.
 

cwbullet

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What is your point? I have never flown a 75 or 98 mm or CTI that contains a pellet. Then again, I have not flon them all. I suspect the igniter is dipped to ensure it will light without a pellet.
 

watermelonman

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What is your point? I have never flown a 75 or 98 mm or CTI that contains a pellet. Then again, I have not flon them all. I suspect the igniter is dipped to ensure it will light without a pellet.
No point, simply trying to determine what is out there and how each product is sold. As a technical aside I had long assumed that using both would make overpressurization likely.

It sure would be nice if they had per motor instructions and part lists.
 

cwbullet

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I would recommend against adding to the motor. Pellets are not needed. They igniter with the provided igniter. As a prefect, I have only seen CATOs on 75mm and higher when they are augmented.

I only have 6 CTI 75 or higher flights, I have never had to use anything but the provided igniter/e-match.
 

wyo17

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For 75mm and up if the provided igniter doesn't work an e-match and Triple 7 works very well. Just a good clean burn and light the motor every time.
 

tfish

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per CTI's FAQ...Tony


Can I use a different igniter?

Theoretically yes, but… why? You will not add any reliability with another igniter, but you certainly may lose some. The ignition system on Pro38 and Pro54 motors is exactly that - a system, and it works. Commercial electric matches are very reliable, and there is more than enough output from the pyrogen to ignite the igniter pellet contained in the top of the motor core.

Some time ago we experimented on the test stand with progressively larger and larger gaps between the electric match and the igniter pellet. The final test was successfully igniting a 6 grain Pro38 with the electric match head inserted only 1" into the motor. This is not recommended! It merely demonstrated that it was not critical to have the match head in tight contact with the igniter pellet.

If you insist on using a homemade pyrogen-dipped igniter, think about this first: we recently precisely reproduced an unusual failure of a Pro38® J class reload. The flier reported that at ignition, his motor ignited with a small flame and no thrust, and continued to burn for over a minute, with the rear end of the motor case melting and dripping into a puddle of aluminum. The rocket was destroyed. We asked the usual questions, including asking if the stock igniter was used, and if the flier made sure it was all the way up the motor core. Both answers were "yes".

This left us baffled for a while, until eventually we decided that the only way this could happen is for ignition to have occurred near the nozzle of the motor. We also knew that the stock match would not ignite the propellant directly, so how could this happen? We took a few reloads out to the test stand with some electric matches, plus a couple of pyrogen-dipped igniters.

The electric match would not ignite the propellant by itself, as we already knew. We then installed a dipped igniter a short way inside the motor, and pressed the button. Bingo! The motor burned like a road flare for about 90 seconds, and the rear of the motor case melted into a puddle of aluminum just like the failed reload. In fact, we couldn't tell the remains apart. Hmmm…

When asked again, the flier sheepishly admitted he had indeed used a homemade dipped igniter, and we figured it must have caught in the core and felt like it was properly installed, or else slipped out of place. All was forgiven, and we actually learned valuable information from the tests. The flier also said he would stick with the stock igniter from now on!
 

rharshberger

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per CTI's FAQ...Tony


Can I use a different igniter?

Theoretically yes, but… why? You will not add any reliability with another igniter, but you certainly may lose some. The ignition system on Pro38 and Pro54 motors is exactly that - a system, and it works. Commercial electric matches are very reliable, and there is more than enough output from the pyrogen to ignite the igniter pellet contained in the top of the motor core.

Some time ago we experimented on the test stand with progressively larger and larger gaps between the electric match and the igniter pellet. The final test was successfully igniting a 6 grain Pro38 with the electric match head inserted only 1" into the motor. This is not recommended! It merely demonstrated that it was not critical to have the match head in tight contact with the igniter pellet.

If you insist on using a homemade pyrogen-dipped igniter, think about this first: we recently precisely reproduced an unusual failure of a Pro38® J class reload. The flier reported that at ignition, his motor ignited with a small flame and no thrust, and continued to burn for over a minute, with the rear end of the motor case melting and dripping into a puddle of aluminum. The rocket was destroyed. We asked the usual questions, including asking if the stock igniter was used, and if the flier made sure it was all the way up the motor core. Both answers were "yes".

This left us baffled for a while, until eventually we decided that the only way this could happen is for ignition to have occurred near the nozzle of the motor. We also knew that the stock match would not ignite the propellant directly, so how could this happen? We took a few reloads out to the test stand with some electric matches, plus a couple of pyrogen-dipped igniters.

The electric match would not ignite the propellant by itself, as we already knew. We then installed a dipped igniter a short way inside the motor, and pressed the button. Bingo! The motor burned like a road flare for about 90 seconds, and the rear of the motor case melted into a puddle of aluminum just like the failed reload. In fact, we couldn't tell the remains apart. Hmmm…

When asked again, the flier sheepishly admitted he had indeed used a homemade dipped igniter, and we figured it must have caught in the core and felt like it was properly installed, or else slipped out of place. All was forgiven, and we actually learned valuable information from the tests. The flier also said he would stick with the stock igniter from now on!
The OP was referring to the 98mm motor he saw someone getting ready to fly, and the igniter the individual was using. 38s and 54s have been referenced only be cause they have ignition pellets and 75s and 98s do not.
 

jimzcatz

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Chuck, I guess I should have been more specific. I tend to lose things, especially those dipped igniters. I only use pellets for clusters. I have a never ending supply of ematches and quite alot of CJ motor starters. By the time I'm actually ready to take something to the pad with a 75mm motor, the supplied igniter is history. Yea, I know,my bad.
 

tfish

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Rich. I see that in the OP...My posting from CTI's site....Using a different igniter...and talks about pellets in 38 and 54mm motors (without mentioning pellets in 75 and 98mm motors, sort of leads me to believe pellets are not used in 75 and 98mm motors) (hence what the OP saw was not an official CTI ignition system) My posting from CTI's site seemed relevant to the OP's question. I'll remove my replies if you believe it's not relevant.

Tony
 

rharshberger

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Rich. I see that in the OP...My posting from CTI's site....Using a different igniter...and talks about pellets in 38 and 54mm motors (without mentioning pellets in 75 and 98mm motors, sort of leads me to believe pellets are not used in 75 and 98mm motors) (hence what the OP saw was not an official CTI ignition system) My posting from CTI's site seemed relevant to the OP's question. I'll remove my replies if you believe it's not relevant.

Tony
No Tony, it was my misunderstanding as to the OPs question. PM sent. I believe you are correct, afaik there are no ignition pellets in any of the 75 or 98mm CTI motors.
 

JimJarvis50

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No Tony, it was my misunderstanding as to the OPs question. PM sent. I believe you are correct, afaik there are no ignition pellets in any of the 75 or 98mm CTI motors.
The N1100 has something in it. I'm pretty sure that it has a propellant slug. Less sure about a pellet. But, the motor is not just an open core.

Jim
 

cwbullet

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Chuck, I guess I should have been more specific. I tend to lose things, especially those dipped igniters. I only use pellets for clusters. I have a never ending supply of ematches and quite alot of CJ motor starters. By the time I'm actually ready to take something to the pad with a 75mm motor, the supplied igniter is history. Yea, I know,my bad.
Jim,

I was not criticizing you. I have used an alternative igniter with 54 mm CTI when the provided igniter fails (only one has failed). It failed because it was manhandled before I bought it.

I would use the provided igniter alone first to preserve the warrantee. When I has a 38mm CATO, CTI asked if I used the provided igniter or my own.
 

tfish

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CTI 75 -98mm Moonburners: These motors incorporate a small starter grain similar to the starter pellets used in our Pro38® and Pro54® series of
rocket motors. The supplied igniter is sufficient to ignite this motor, and no additional pyrogen is required. Simply
ensure the igniter is pushed all the way up and in contact with the top of the motor core. There will be an ignition delay
of 2-3 seconds so use appropriate care if clustering with outboard motors having faster ignition characteristics.

http://www.pro38.com/pdfs/Moonburner_supplement_segmented_V1.1.pdf

Tony
 

rharshberger

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CTI 75 -98mm Moonburners: These motors incorporate a small starter grain similar to the starter pellets used in our Pro38® and Pro54® series of
rocket motors. The supplied igniter is sufficient to ignite this motor, and no additional pyrogen is required. Simply
ensure the igniter is pushed all the way up and in contact with the top of the motor core. There will be an ignition delay
of 2-3 seconds so use appropriate care if clustering with outboard motors having faster ignition characteristics.

http://www.pro38.com/pdfs/Moonburner_supplement_segmented_V1.1.pdf

Tony
Good to know, thanks.
 

watermelonman

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CTI 75 -98mm Moonburners: These motors incorporate a small starter grain similar to the starter pellets used in our Pro38® and Pro54® series of
rocket motors. The supplied igniter is sufficient to ignite this motor, and no additional pyrogen is required. Simply
ensure the igniter is pushed all the way up and in contact with the top of the motor core. There will be an ignition delay
of 2-3 seconds so use appropriate care if clustering with outboard motors having faster ignition characteristics.

http://www.pro38.com/pdfs/Moonburner_supplement_segmented_V1.1.pdf

Tony
Aha! That is the missing key, thanks.
 

tfish

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we've all learned something..

Tony
 
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