Prepacking RMS motors?

The Rocketry Forum

Help Support The Rocketry Forum:

DynaSoar

Well-Known Member
Joined
Mar 15, 2004
Messages
3,022
Reaction score
0
I've been keeping all my reloads in their packages until I'm ready to use them. But I'm looking at prepping 10 birds. Seems to me that prepping the motors when I buy them, and storing them that way, would save some time come night before launch day. Is it OK to load the motors and let them sit in storage, or are they better left in the package?
 

jrogers

Well-Known Member
Joined
Jan 18, 2009
Messages
498
Reaction score
0
It depends on the motors, the Aerotech RMS motors can be stored assembled as long as the closures are not tightened all the way, AMW motors ( with the paper liners ) on the other hand is a different "animal", the grease will soak into the paper and you could have serious problems ( Motors with the phenolic liner "may" not soak the grease )

Joel
77267
9848
L3
 

BlueNinja

Well-Known Member
Joined
Jan 18, 2009
Messages
2,701
Reaction score
1
If you're using whitelightning, it will probably oxidize a lot. I once stored an F40 in a ziploc bag (dunno why) and it got all condensed inside, I'm gonna use it for igniters in a while if it burns OK.
 

Ryan S.

Well-Known Member
Joined
Mar 24, 2003
Messages
3,553
Reaction score
0
you will probably be okay, if you do end up loading them a while in advance, put them in a ziploc batg a remove as much air as possible, especially with WL and RL
 

loopy

Well-Known Member
Joined
Dec 13, 2009
Messages
4,586
Reaction score
2
Don't tighten the closures all the way if you're storing them, even overnight. Loosen the closures to take pressure off of the O-rings, and seal them as close to air tight as possible.

Loopy
 

loopy

Well-Known Member
Joined
Dec 13, 2009
Messages
4,586
Reaction score
2
Wait - wasn't there something awhile back about delays shortening in burn time when exposed too closely to the BT propellant? I don't know if that would matter too much in this situation...
 

n3tjm

Papa Elf
Joined
Jan 21, 2009
Messages
7,575
Reaction score
463
Location
Penns Creek, PA
It would not matter becasue in a loaded RMS, the delay grain never comes in contact with the propellant.

The new RMS+ motors can be loaded indefiantly. The problem with the old delay system was the delay o-ring sat on top of the delay grain. With the closures tightened, the o-ring is compacted into the delay element. Over time, the delay would settle (get used to it), so the seal will not be as good.

With the new RMS+ Delay... this is no longer a problem. The o-ring sits outside the delay element, and its tight squeze between the wall of the delay well and the rubber casting of the delay grain creates the seal.

AMW loads, I have loaded and kept them loaded for a while. I don't think I ever had a problem of the grease soaking throught the liner... I guess it dpnds on the grease you used.
 

solrules

Well-Known Member
Joined
Dec 30, 2003
Messages
366
Reaction score
0
Originally posted by Loopy
Wait - wasn't there something awhile back about delays shortening in burn time when exposed too closely to the BT propellant? I don't know if that would matter too much in this situation...
I remember at Rockets for Schools 2004, thre were about 7 flights of large rockets on 54mm blue thunder with medusea type nozzle (don't know exact designation). The motors were left over from the last rockets for schools, where the weather was bad but the motors were already prepped. They got recycled to the 2004 launch. I believe the motors all had long delays. Every single flight on the old blue thunder motors had a very early ejection. The rockets were fine, but they could have had about 700' more altitude if they did not eject so soon.

Oh yeah, I believe AT now packages the delay in a seperate section than the propellant in the 29mm high power loads.
 

jetra2

Well-Known Member
Joined
Jan 25, 2009
Messages
2,795
Reaction score
2
Originally posted by n3tjm
The new RMS+ motors can be loaded indefiantly. The problem with the old delay system was the delay o-ring sat on top of the delay grain. With the closures tightened, the o-ring is compacted into the delay element. Over time, the delay would settle (get used to it), so the seal will not be as good.
That is VERY good, from what I see. According to the new ruling from the judge, that means you could buy the motor on site a month or more before the next launch, have a LEUP person load the motor, and then keep the motor loaded at your residence for as long as you want!

Jason
 

llickteig1

KLOUDBusters Chief Logistician
Joined
Jan 23, 2009
Messages
1,692
Reaction score
407
Location
Wichita, KS
Originally posted by DynaSoar
But I'm looking at prepping 10 birds.
Wow, you have 10 sets of RMS hardware? I'm jealous. :)

Your worst enemies will be moisture and poor o-ring seals, so as has been stated, when assembling the motors leave the closures a little loose and after loading the motors, carefully seal them in air tight bags until time to burn them. Do not load the BP ejection charges until flight time. To be on the safe side, store the bags of assembled motors in a dry place.

Make sure you don't forget to tighten the closures completely before flying or bad things will happen. Then after retightening, add the BP and go.

--Lance.
 

DynaSoar

Well-Known Member
Joined
Mar 15, 2004
Messages
3,022
Reaction score
0
Originally posted by llickteig1
Wow, you have 10 sets of RMS hardware? I'm jealous. :)

Your worst enemies will be moisture and poor o-ring seals, so as has been stated, when assembling the motors leave the closures a little loose and after loading the motors, carefully seal them in air tight bags until time to burn them. Do not load the BP ejection charges until flight time. To be on the safe side, store the bags of assembled motors in a dry place.

Make sure you don't forget to tighten the closures completely before flying or bad things will happen. Then after retightening, add the BP and go.

--Lance.
Actually I only have 4 sets of hardware, but 10 birds to fly. Most will get S/U motors, which I can prep ahead (except I'll wait to put in the ignitors so they don't get bumped in transport). I'm just trying to minimize the time in the field spent prepping.

Considering the fact that humidity is a problem for this, and we're having a great deal of that, perhaps it's best I just plan to do them in the field.

And considering the fact that chasing down that many birds could result in several miles total walking in a hot, humid hayfield, maybe I'll just rethink the whole thing. Like either stop building them faster than I can fly them, or arrange with some other folks for launches between our monthlies. I'll lanch LPR birds by myself all day long, since I can afford to decide it's not worth wading through a mile of tall grass for $10 model, but the big ones I can't do that with.

Thanks for the tips, folks.
 
Top