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  #1  
Old 07-29-2010, 09:19 AM
tgienger tgienger is offline
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Default RMS engines

Just ordered my first Aerotech RMS casing and reloads. Are these something you can rebuild in the field? Or do most of you have multiple casings and do the reloads at home?

Any tricks that I should know about with them?

Thanks.
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Old 07-29-2010, 09:26 AM
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gpoehlein gpoehlein is offline
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Yes, they can be assembled at the field (and must be if used in NAR competition as you have to check in the reload before assembling it). Only other tip I can give, since I haven't used them very much, is to clean them immediately. If you clean them after use you can use baby wipes to clean all the residue out. If you let them sit for a couple days, you'll have to used vinegar and really scrub them.

Greg
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Old 07-29-2010, 09:40 AM
Ltvscout Ltvscout is offline
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Hoppe's #9 works great for cleaning cases as well. Plus, the nitro smell is awesome!
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  #4  
Old 07-29-2010, 09:59 AM
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Quote:
Originally Posted by Ltvscout
Hoppe's #9 works great for cleaning cases as well. Plus, the nitro smell is awesome!

Gotta love Hoppes #9, great stuff!
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Old 07-29-2010, 10:20 AM
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GregGleason GregGleason is offline
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Quote:
Originally Posted by Ltvscout

Hoppe's #9 works great for cleaning cases as well. Plus, the nitro smell is awesome!



+2 on Hoppe's #9.

Yes, you can assemble them at the field and that is my practice most of the time. It helps to have a space set aside to do this. My "space" is the top of a copy paper box.

If you choose to do build in the field, it wouldn't hurt to review the instructions and the parts the night before. You can even go through a mock motor build to simulate what you will do the next day.

Key points for the AeroTech RMS:

1. Take as much time as you need. Don't rush. Your first RMS may take a while, since it is unfamiliar. Just keep focused and start your work.

2. Make sure you use all the parts. Something left over (unless it is a 3-pack) means you left something out.

3. Don't get any grease on the delay grain, as it can add a second or more to the delay.

4. Only put enough silicon grease on the O-rings to make them shiny (don't overdo).

5. Make sure the forward and aft closure are on tight. You will feel resistance on the last little bit as the propellant and parts are compressed.

6. DON'T forget to add the red cap with the black powder (I have almost done this). Tap the top of the cap to make sure the BP travels down into the well.

7. When you place the igniter into the motor, make sure the igniter is all the way at the top most part of the propellant, but don't go beyond it. That is why I often will place a strip of masking tape over the top of the upper propellant grain so that the igniter will stop. Once ignition happens, the tape is consumed by the heat and does not impede the delay grain progress.

8. Sometimes the igniter will fail to light the motor. It happens. Sometimes often. Just try again. Some have had success with Quest Q2G2 igniters, but not all ignition systems are compatible with these igniters.

REMEMBER: enjoy the moment! Have your "mind recorder" going so that you can enjoy it in the future.

Greg
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Old 07-29-2010, 10:41 AM
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Doug Sams Doug Sams is offline
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Quote:
Originally Posted by GregGleason
If you choose to do build in the field, it wouldn't hurt to review the instructions and the parts the night before. You can even go through a mock motor build to simulate what you will do the next day.
I like to tape the instructions down to the table top and build on top of them. It keeps them from getting taken by the wind.


Quote:
2. Make sure you use all the parts. Something left over (unless it is a 3-pack) means you left something out.
I split the 3-packs into three zip-lock snack baggies (before heading to the field). Then, rule #2 applies without qualification


Quote:
3. Don't get any grease on the delay grain, as it can add a second or more to the delay.
4. Only put enough silicon grease on the O-rings to make them shiny (don't overdo).
I keep some baby wipes handy while building. These are the unscented, lotion-free kind. I thoroughly clean my hands after lubing the o-rings and other bits that get lubed before handling the delay grain.

Doug...adding to Greg's excellent summary

.
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Old 07-29-2010, 11:51 AM
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ghrocketman ghrocketman is offline
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As an addition to Greg's above procedure, make sure the propellant grains do not show a LOT of oxidation as this will make them extremely hard to ignite.
This most often happens with "White Lightning" propellant and shows up as crusty white residue on the slot and ends of the grain(s). If this is present (most likely on older loads or 3-paks of 24mm reloads that have been opened for a while), use an emery board to lightly sand the slot of the grain, which will improve ignition reliability at least 5-fold.
Otherwise you may get either zero ignition or several seconds of propellant consuming "chuffs" that can reduce the in-flight impulse by 50%.
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Old 07-29-2010, 12:11 PM
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Quote:
Originally Posted by gpoehlein
Yes, they can be assembled at the field (and must be if used in NAR competition as you have to check in the reload before assembling it). Only other tip I can give, since I haven't used them very much, is to clean them immediately. If you clean them after use you can use baby wipes to clean all the residue out. If you let them sit for a couple days, you'll have to used vinegar and really scrub them.

Greg
I've always made a point of cleaning them right after use with baby wipes because I was told they would be hard to clean if I didn't. When I get home from a launch, I will clean them with dish soap and water using an old toothbrush.

But last year at one of our launches, I had one of my rockets spit the case and I couldn't find it even after a long methodical search.

At the next launch, 2 weeks later, I just happened to walk over in that area to recover my first launch of the day and the case was sitting on the ground not more than 20 ft from where my rocket landed.

I took it apart, cleaned it with baby wipes and it looked good to me so I loaded it up and used it for 2 (or 3, I can't remember) launches that day.

After each launch I cleaned it in the field and when I got it home, it didn't look any dirtier than after any other days launch and cleaned up with soap and water like usual..

EDIT: I don't know if the type of propellant makes a difference.. I lost it using Blue Thunder propellant and it's usually not very dirty when I use an F39-4T but is very dirty after using an F12-5J for example.
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Last edited by Bob H : 07-29-2010 at 12:28 PM.
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  #9  
Old 07-29-2010, 01:36 PM
Mikus Mikus is offline
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Quote:
Originally Posted by GregGleason
Just keep focused...


Excellent tips. This one is very important as the penalty for screwing up can be high.

Heh, I don't like people even talking to me when I assemble them.
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  #10  
Old 07-29-2010, 01:40 PM
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ghrocketman ghrocketman is offline
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Blackjack tends to be the dirtiest propellant BY FAR when it comes to cleaning cases.
White Lightning is not too bad.
Blue Thunder is the cleanest, with Redline and Mohave Green just slightly dirtier.
I have not flown Warp 9, but expect it is even cleaner than Blue Thunder.
Seems that the faster the propellant is, the less residue/crud it leaves to be cleaned.
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Yes, there is such a thing as NORMAL
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ALL systems are GO for MAYHEM, CHAOS, and HAVOC !
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