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Reloadable Casings

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Mad Rocketeer

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OK, I've never used a reloadable casing, but I plan to use them in my LOC Graduator, once I break it out and build it. I've got a book that shows examples of reloading them, but I'd like to see a basic exposition on the selection and use of casings, the marking code, selection of loads. You see explanations of the C6-5 type markings absolutely everywhere, but I've seen much less about the Aerotech / Dr. Rocket style stuff and markings. Does Aerotech publish anything on that? Other source?
 

JDcluster

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If your are talking about Motor coding, than it's pretty much the same. Just a few more rungs up the same ladder.
A "D" motor is twice the power of a "C" motor so on & so forth.

For instance an AT G80-10T would be a motor with a Ns Ranging from 80.1Ns to to 160.0 Ns. 80 is the average thrust. The 10 is the timed delay from motor burn out (even though it starts burn at motor ignition) The "T" stands for the type or formulation of propellant that the motor contains, in this case it is a Blue Thunder. It usually give a High thrust for a short duration & produces a blue colored flame.

See this link for details:
http://www.aerotech-rocketry.com/customersite/products/products.html


JD
 

BlueNinja

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OK, reload casings


29/40-120


The 29 is the motor diameter in millimeters.

40-120 is the range of Ns that can be used with that specific case. As I under stand it, when you get up into HPR, the casings have a VERY limited load selection. This means if you see, say (this isn't an accurate number, just a random shot) 98/9000-10250, this will mean that it comes with ONE set of closures and several casings. The 29/40-120 is the odd one out, it is probably the most versatile and has a semi-wide range of Ns in one package. I believe it has 3 different W loads, a T load ocming out (or already in production) and one or 2 blackjacks (G33 for one)
 

r1dermon

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if you want to know what reloads are compatable with what casings, magnum has the whole list on their catalog. www.magnumrockets.com for the graduator, you're definately going to want the 29/40-120. its the most versatile casing out there. you can use D reloads in it, all the way up to G's. the only bad thing about it is, the closures arent interchangeable with any other 29mm hardware. so if you wanted to get a cert on an H motor, and you got a 29/180 casing, the closures wouldnt fit on it, so you'd need to buy a whole new complete motor. when you start buying higher power casings definately buy them in sets, they're a lot cheaper. like the 38/240-480 for instance. buying them individually is not cost effective.;)
 

Mad Rocketeer

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Ahhh! Dawn begins to break. :) I knew about the extension of the motor total impulse - average thrust - delay codes. Info on the casing codes, like the 29/40-120 that was mentioned, was what I was specifically seeking. I knew about the diameter part and had read that the part after the / was a total impulse limit. But I had no idea what 40-120 might mean. How would that differ from just 120, etc.? Now I get it. That would be a set of 2 or more casings, covering that range. Seems interesting that the limits would indicate total impulse (which is related to fuel volume) but not peak thrust (which should be related to max internal pressure and thus to casing strength). I guess the casings must have quite a bit of extra strength as a margin of error, making any reasonable loading in the total impulse range workable in terms of peak internal pressures. Thanks for the links. I'll dig further from there. Any additional tutorial comments folks might want to contribute to my education here would be appreciated too. There's bound to be a lot of others who'd like to understand the ins and outs of reloadables better too, so you'll help more than just me.
 

r1dermon

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the 29/40-120 is a single casing that covers that entire range. its weird, because the other sets like the one i mentioned, the 38/240-480, thats 3 casings. the reasons are varied, but the 29/40-120 is like the case that does it all. from D loads to G loads. the 38/240 case can't handle the length of I loads, so the 360 comes in, so does the 480. in that SET. however, for 29mm hardware, the 29/40-120 is not even half of the impulse range as the highest 29mm hardware, however, a 29/360 is a LOT longer than a 29/40-120, so with the bigger motors comes the bigger loads, and to add extra volume and subsequent power without comprimising the minimum diameter(29mm) you lengthen the case, which is what aerotech did with their I200.
 

cjl

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No, the 29 40-120 only does E, F and G (40 is the top of an E, 120 is midsize G). It does have 7 reloads, however. Everything from an E16W to a G64W. It has two e's (one white lightining, one blue thunder), three f's (one of each propellant), and two g's (one black jack, one white lightining). If you want D's as well, get the three casing set with the 18, 24, and 29 40-120 casings.
 

r1dermon

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woops, my B, sorry man. i thought that it had 2 D's, lol, thats what the 24/40 casing is for. heh. the D9 and the D15. that case also has quite a few reloads for it. 1 more reload than the 29/40-120, at least according to magnum. sorry for the mixup
 

Mad Rocketeer

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Is there really an advantage to using reloadable casings in the 18 or 24 mm sizes? E.g., how many launches (assuming single motor) does it take for an 18mm reloadable casing and loads to be cheaper than just using Estes or Quest single use motors? Is it mainly done in order to get different motor characteristics not covered by the single use stuff? Factoring in the potential to lose the casing and the extra weight and possible resulting stability issues in small rockets, I'm thinking that my reloadable stuff should start at 29mm.
 

r1dermon

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no way man, look, an estes D12 retails for about 13 bucks for 3, thats more than 4 bucks a pop. plus, you need a 24mm MMT to use it. however, an aerotech D13 is 10 bucks for 3 which is about 3.33 per load. so its about 70 cents cheaper. not only that, but it IS lighter than the casing for the estes motors. so, if you have a severely underpowered rocket with an 18mm motor mount, then its great, or, if you would just like to bust mach in a little beta rocket, thats also cool too. 30 bucks for the casing, not only that, but it looks cool too. i can see your point, but the D13 and D24 are the 2 loads available, estes doesnt make ANYTHING with that much impulse. even the D13 beats their highest impulse rocket, on average. im not sure about peak. but i'd guess that the D13 also beats the peak impulse. a REALLY good case to get is the 24/40 and the 29/40-120. very versatile. plus, there's no hazmat fee for any of the reloads.
 

Flyingiazzi

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It is true that you can save money using reloadable motors. I use the 29/40-120 RMS, and it is quite a bit cheaper per flight. A reloadable G64W retails for about $12; a simililar single use motor, the G80T, is about $20. Another reason I like to load my own motors is that it is fun. You are more involved in the launch of your rocket. To find out more about loading motors, Aerotech's website has several video clips demonstrating the assembly procedure, and you can also download the instructions. It is a very good idea to go over them several times before loading your motor. Have fun!!!
 
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