What to do with unflown G-motor composite reloads...

[bronicabill]

On my last club launch, I had pre-loaded two 29/40-120 motor casings with G76 reloads. I flew one of them but then began to feel really poorly and left the field before flying the second one.

What do you guys feel I should do with the motor hardware and reload; just leave it loaded until the next launch, or disassemble it and put the reload in a zip-lock bag until time to fly again? If it matters any, I do NOT use motor ejection, so there is no BP charge in the forward end cap, and certainly no igniter installed!

Thanks!

 

[Voyager1]

If it’s not too long to the next launch, I’d probably just bag the lot as it is. Otherwise, I’d remove and bag the reload. Either way, you want to reduce the chances of allowing the reload to swell up as the propellant is hygroscopic.

 

[bronicabill]

The next launch is November 13th, weather permitting, so I'll just leave it assembled and not worry about it for now. Thanks!

 

[Steve Shannon]

On my last club launch, I had pre-loaded two 29/40-120 motor casings with G76 reloads. I flew one of them but then began to feel really poorly and left the field before flying the second one.

What do you guys feel I should do with the motor hardware and reload; just leave it loaded until the next launch, or disassemble it and put the reload in a zip-lock bag until time to fly again? If it matters any, I do NOT use motor ejection, so there is no BP charge in the forward end cap, and certainly no igniter installed!

Thanks!

This is a fairly frequently asked question. There’s no reason to ever unload a motor. Some people will tell you to loosen the closures, but I never do that either. O rings don’t suddenly lose seal because they’re compressed. If they did it would be impossible to have single use motors. I’ve had assembled motors sit months before use. It’s good to know exactly what has been assembled though, such as BP. I have made the mistake of flying a motor that I had assembled the previous season without remembering that the BP hadn’t been added. I should have left myself a note, but didn’t. That lawn dart was completely avoidable and unquestionably my fault.

 

[tOD]

This is a fairly frequently asked question. There’s no reason to ever unload a motor. Some people will tell you to loosen the closures, but I never do that either. O rings don’t suddenly lose seal because they’re compressed. If they did it would be impossible to have single use motors. I’ve had assembled motors sit months before use. It’s good to know exactly what has been assembled though, such as BP. I have made the mistake of flying a motor that I had assembled the previous season without remembering that the BP hadn’t been added. I should have left myself a note, but didn’t. That lawn dart was completely avoidable and unquestionably my fault.

I put a piece of making tape on the assembled motor with all the specifics, propellant type, delay time, bp charge weight, assembly date, etc.

 

[Bat-mite]

Steve and tOD nailed it. Leave them loaded indefinitely. And label them. Nothing like finding a loaded motor six months later and thinking, "Now, what did I put in here again ... ?"

 

[readytorock556]

I’ve had reloads loaded for a year and they worked fine. I just replace the BP before go time.

 

[Ronz Rocketz]

I was watching the video @James Duffy has on the British V2 program. The Germans launch the V2 within 3 days of assembly because the Germans determined that failures are more likely the longer it's in storage. Of course that's with the rocket and not the propellent, but I thought it was interesting anyways.

 

[manixFan]

I've launched motors that were loaded YEARS ago! But I always try and make sure they are sealed - moisture is the enemy of nearly everything, and many propellant formulations are either hydroscopic or otherwise react negatively with moisture. So sealing the motor somehow from moisture is the number one thing you can do to protect it. Aerotech also says in its instructions to loosen the closures a couple of turns to take pressure off the o-rings. If I find a motor I loaded long ago, I'll sometimes disassemble it and check the o-rings and re-grease them during reassembly.

When I was a Prefect I had a lot of guys contact me when they were getting out of the hobby and I'd end up buying their odds and ends. Many times that included 'mystery motors' that they had loaded and then never flown. I know at least several that were about 20 years old, and flew ok. But on one, it chuffed for a good 30 seconds and when it did come up to pressure, it was probably only about 1/4 of rated impulse. That flight did not end well. It got so bad that I got a reputation as the 'mystery motor' flyer. The biggest issue I had was getting the reloads to light. Many of them had to be sanded or scraped to expose fresh propellant that would readily light.

Label it, seal it up, and you'll be fine.


Tony

 

[bronicabill]

Steve and tOD nailed it. Leave them loaded indefinitely. And label them. Nothing like finding a loaded motor six months later and thinking, "Now, what did I put in here again ... ?"

Since I only fly one specific type of propellant in my 29/40-120 hardware (G76W), then I really don't have a need to label them. If by chance I ever try anything else, then I will start doing that when needed. But thanks for the awesome idea as I never would have thought to do that myself... at least I don't think I would!

 

[mrwalsh85]

I picked up a 29/40-120 case with a reload in it. I found the case last night and it still has the reload in it.

Time to find a sacrificial rocket and put an igniter in it to find out what motor it is!

Mike

 

[David Schwantz]

I am sorry guys, but you CANNOT leave motors stored in casing for a long time. The ACPC will eat through the casings. I just by chance have a Hazmat disposal site near me. I would be more than happy to dispose of them for you, at no charge. You will also need to send me the casing. Please PM me for shipping info.Your welcome, Dave

 

[David Schwantz]

Ahh! Just kiddin. You can leave them in for as long as needed. Saturday I will fly a AT L1090 W that has been in the case for more than a year. Good luck.

 

[mrwalsh85]

The motor for Marvin the Martian (6" O motor) has been built for over a year. *shrug*

 

[manixFan]

Since I only fly one specific type of propellant in my 29/40-120 hardware (G76W), then I really don't have a need to label them. If by chance I ever try anything else, then I will start doing that when needed. But thanks for the awesome idea as I never would have thought to do that myself... at least I don't think I would!

White lightning propellant is one of those that does not like moisture. Make sure to keep those in a sealed bag or at least tape over the nozzle. Otherwise you’ll end up with hard to light grains or worse, grains that have swollen enough that the slot becomes so small you can’t get an igniter in it. I’ve had poorly stored WL reloads that would not even come close to fitting in the liner they had swollen so much.


Tony

 

[Bat-mite]

Yeah, roll it in static-free plastic wrap, or seal it in a Ziplock if moisture is excepted to be a problem.

A common scenario for me is, it's the last launch at our winter (high waiver) field, and I have a big motor ready to go and ... it rains. Now I can't launch that sucker for six or seven months.

I put it in the basement and bring it out when we go back to that field.

 

[heada]

Unscrew the aft closure, stretch some saranwrap over the nozzle and re-install the aft closure. Its now sealed and when you want to use it, just pop the igniter through the saranwrap.

 

[GlueckAuf]

In a related vein, by the letter of the law, the (unreasonable, in my view) warranty on Aerotech RMS motors (of any size) expire just 12 hours after they're assembled. I defer starting the clock by leaving out the BP and/or igniter--both of which are included, essential components of the motor--until I'm sure I'll be using the motor.

That's my story and I'm sticking to it.

 

[Sooner Boomer]

I prefer to assemble my motors sitting on the couch rather than out in the field where the wind fights you and blows stuff around. I place the assembled RMS (without the BP) in an appropriate sized zip lock bag (usually sandwich or snack sized) drop in a dessicant pack (I get several a month in medication), and seal the bag. When I get to the field, I add the BP (and red cap), stick an igniter in (and red cap). Now it's ready to fly!

 

[beeblebrox]

Just to be safe, disassemble the motor, inspect the grain(s), if crusted over, like white lightning and redline are sometimes, clean out the core with a drill bit, you can do it by hand. lightly sand the ends with coarse sandpaper. (No need to mess with the delay charge.) Re-grease the o-rings and reassemble shortly before flying. Note: White lightning is greenish, blue thunder is brown, redline is a light greyish green. might be enough info to figure out what it is from the AeroTech motor matrix. Post photos if not sure.

 

[bronicabill]

In a related vein, by the letter of the law, the (unreasonable, in my view) warranty on Aerotech RMS motors (of any size) expire just 12 hours after they're assembled. I defer starting the clock by leaving out the BP and/or igniter--both of which are included, essential components of the motor--until I'm sure I'll be using the motor.

That's my story and I'm sticking to it.

View attachment 487701

I don't use BP in mine, and I never install the igniter until I'm ready to walk it to the flight line, so will assume mine are not "assembled" yet either!

 

[jimzcatz]

I am sorry guys, but you CANNOT leave motors stored in casing for a long time. The ACPC will eat through the casings. I just by chance have a Hazmat disposal site near me. I would be more than happy to dispose of them for you, at no charge. You will also need to send me the casing. Please PM me for shipping info.Your welcome, Dave

I gotta call bull on this. I have had loads in cases for years. Besides the propellant is in a liner so there is no contact .
Oh,wait...I get it...Nicely done!!

 

[John Taylor]

On my last club launch, I had pre-loaded two 29/40-120 motor casings with G76 reloads. I flew one of them but then began to feel really poorly and left the field before flying the second one.

What do you guys feel I should do with the motor hardware and reload; just leave it loaded until the next launch, or disassemble it and put the reload in a zip-lock bag until time to fly again? If it matters any, I do NOT use motor ejection, so there is no BP charge in the forward end cap, and certainly no igniter installed!

Thanks!

It's fine to leave them assembled. Think of DMS and SU motors. They can remain assembled for years.

 

[kjhambrick]

Here is one ...

I've been doing an inventory of what I have from 2000 or so,

I found a loaded motor my Motor Box in an RMS 29/240 Casing that was stored in a ZipLock Baggie a VERY long time ago.

The Motor is completely assembled except for the BP which is still in the two plastic caps and the old copperhead is also there in the cardboard tube.

The paperwork is in the baggie with the Motor Casing and it says the motor is a G75-J Long from Batch DEC 13 1999.

Dooh !

Hint: A G75 goes in an RMS 29/180 Case !

Dumb A** !!

I popped the Nozzle and checked -- the casing is 'full' of Propellant and it looks like Black Jack so it is definitely not a G75 in there ...

Maybe time for a static test ?

-- kjh oh well atleast DEC 13 1999 was a Monday and not a Friday

 

[John Taylor]

Here is one ...

I've been doing an inventory of what I have from 2000 or so,

I found a loaded motor my Motor Box in an RMS 29/240 Casing that was stored in a ZipLock Baggie a VERY long time ago.

The Motor is completely assembled except for the BP which is still in the two plastic caps and the old copperhead is also there in the cardboard tube.

The paperwork is in the baggie with the Motor Casing and it says the motor is a G75-J Long from Batch DEC 13 1999.

Dooh !

Hint: A G75 goes in an RMS 29/180 Case !

Dumb A** !!

I popped the Nozzle and checked -- the casing is 'full' of Propellant and it looks like Black Jack so it is definitely not a G75 in there ...

Maybe time for a static test ?

-- kjh oh well atleast DEC 13 1999 was a Monday and not a Friday

I'm not sure how BJ acts with age but WL will swell with age. I would say if the grains are not deformed, and you can get an igniter in there it's probably fine.
Since you loosened the closure the o rings may have been compressed for too long. I personally would take it apart, inspect everything and replace all o rings.
If it had been left assembled it would probably have been fine.

 

[kjhambrick]

John --

Yes, I planned on setting the propellant grains aside for now so I could use the RMS 29/240 for a newer Batch of get-up-n-go-juice

My real point ( one that I didn''t even make ) was: Label your pre-assembled motors ACCURATELY

-- kjh

 

[terryg]

Sounds like it could be an H97J. The copperhead ignitor is strange though. Were copperheads ever used for HP motors?

 

[Pem Tech]

So leaving a loaded casing on the stove-top behind the bacon grease crock for a few years is not a good thing?

 

[kjhambrick]

Sounds like it could be an H97J. The copperhead ignitor is strange though. Were copperheads ever used for HP motors?

Yes they were in the Olden Days when this motor was batched up.

-- kjh

 

[VTS SkunkWorks]

I'm not sure how BJ acts with age but WL will swell with age. I would say if the grains are not deformed, and you can get an igniter in there it's probably fine.
Since you loosened the closure the o rings may have been compressed for too long. I personally would take it apart, inspect everything and replace all o rings.
If it had been left assembled it would probably have been fine.

I was told by Gary, as I recall, that you need to loosen the closures for storage or the o rings will deform and not seal.