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How does the parachute ejection with a reloadable casing work?

Thanks.
 
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ScrapDaddy

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Assemble as per instructions, and everything will work like a BP motor
 

MarkII

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How does the parachute ejection with a reloadable casing work?

Thanks.
Some types of reloadable motors feature sections to hold delay grains along with ejection charge wells built into the forward enclosure. A delay grain and a small amount of BP are included in the reload kit. This is common in reloadable motor sizes up through 54mm.

Other types of reloadable motors, particularly larger ones (75mm and up), are plugged (i.e., the forward enclosures do not contain delay grain compartments and are not drilled in order to permit a delay grain to ignite an ejection charge). If you use those motors, you have to equip your rocket with electronics to trigger the deployment of the recovery system.

Mark K.
 

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Assemble as per instructions, and everything will work like a BP motor
I haven't bought one yet. I was hoping to learn how things worked so I know what to look for and what I'm talking about when I go to buy one. I don't even know what a BP motor is.

I used to launch rockets lots when I was a kid and have built many from scratch, even some cluster and multi stage cluster rockets.

I'm not a complete noob, I just got bored with store bought. I'm 47 now and would like to get past the toy store level. I'm looking at the different assosciations available in my area and have only found one (NAR) that doesn't fly anything past an E. Where does that regulation come from?
 

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Some types of reloadable motors feature sections to hold delay grains along with ejection charge wells built into the forward enclosure. A delay grain and a small amount of BP are included in the reload kit. This is common in reloadable motor sizes up through 54mm.
Mark K.
Nothing that big, I'm going to stick with 38 or smaller until I know what I'm doing.

So I would imagine these casings are multi-piece that screw together in sections and have small holes in each section to transfer ignition?

I don't want to get into electronics right now. And before I get that fancy, I'll probably try just a camera first.

Thanks!
 
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MarkII

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I haven't bought one yet. I was hoping to learn how things worked so I know what to look for and what I'm talking about when I go to buy one. I don't even know what a BP motor is.
BP = black powder. The type of motors that Estes makes.

I used to launch rockets lots when I was a kid and have built many from scratch, even some cluster and multi stage cluster rockets.

I'm not a complete noob, I just got bored with store bought. I'm 47 now and would like to get past the toy store level. I'm looking at the different assosciations available in my area and have only found one (NAR) that doesn't fly anything past an E. Where does that regulation come from?
Field size, usually. Larger motors require larger stand-off distances and tend to fly higher. Higher flights require larger recovery areas. Both of these mean that larger fields are required. Getting access to fields has become a problem all over the country, but it is particularly acute in the east. With that being said, there are still a number of clubs in the eastern US that host high power launches. To be able to purchase high power motors (large Gs and up), you have to be a member of one of the national rocketry organizations (National Association of Rocketry or the Tripoli Rocketry Association) and follow procedures to obtain certification in high power. The details of high power certification can be found at NAR's and TRA's websites.

Mark K.
 

MarkII

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Nothing that big, I'm going to stick with 38 or smaller until I know what I'm doing.

So I would imagine these casings are multi-piece that screw together in sections and have small holes in each section to transfer ignition?

I don't want to get into electronics right now. And before I get that fancy, I'll probably try just a camera first.

Thanks!
A reloadable motor consists of a strong tube (usually aluminum) and, in most versions, two end pieces - a forward closure and an aft closure. The tube is threaded at each end and the closures screw onto it. Here is a picture of a 29mm Aerotech "hobbyline" RMS motor. This motor (the 29/40-120) has reloads ranging from E to G in impulse.

\

At the top is the forward closure (the portion above the upper yellow stripe). The narrow cylinder is hollow and it is where the delay grain is inserted. The very small cylinder at the top is the delay charge well. The gold-colored ring at the bottom is the aft closure. You can find out much more about RMS motors, including a short video demonstrating the assembly of of a reloadable motor, at Aerotech's website.

There are other brands that employ the same principle but use a different style of rear closure (Loki, Gorilla). Finally, there is another major brand (Cesaroni Technologies, or CTI) that has a slightly different approach to reloadable motors. Most of their reloads are pre-assembled into modules that are screwed into a simple metal tube.

Aerotech, Apogee Components and Roadrunner also make single-use composite propellant motors, too. (Actually, Apogee's motors are made under contract by Aerotech.) These are fully assembled motors that are, as the name implies, used once and then discarded. Most of Aerotech's, and all of Apogee's, SU motors are 18mm to 29mm in diameter and are in the D to G range and do not require high power certification to purchase. Roadrunner makes 29mm diameter F and G motors that also do not require HP certification. (One or two of Aerotech's G impulse SU motors have average thrusts that are greater than 80 Newton-seconds or contain more than 62.5 grams of propellant, and are thus classified as high power motors, requiring certification to purchase.)

Finally, there is another type of high power rocket motor, called a hybrid motor, that is used in our hobby. These utilize a whole different technology, and I don't have the room here to go into all of it (nor am I all that well-informed about them anyway).

Hope this helps. And, by the way, welcome back to the hobby and welcome to TRF!

Mark K.
 
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KennB

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Nothing that big, I'm going to stick with 38 or smaller until I know what I'm doing.

So I would imagine these casings are multi-piece that screw together in sections and have small holes in each section to transfer ignition?

I don't want to get into electronics right now. And before I get that fancy, I'll probably try just a camera first.

Thanks!
Looking at the pictures on the club's website, I'd agree with MarkII that your field size is probably limiting motor selection to E-impulse. That would put your reload selection to 29 mm or less.

As I am someone who is finally dipping his toe into the mid-power part of our sport, I'd recommend building your models and starting with single-use motors instead of reloads and moving up from there.

We have a member of our club (CMASS) that loves to fly mid-power saucers on our smaller fields. These are a real crowd pleaser and always recover well.
 

dave carver

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I would also recommend the 24 40 version of the AeroTech motor. D-E-F are avalable for this motor with a F39 Blue Thunder load capable of ripping the fins off of most Estes D-motor rockets. Two of the loads for this motor you kinda have to watch for though. The D15-4 can be...problematical. The delays CAN not function correctly. I've had lots of problems with the Black Jack loads for the 24mm case and no longer use them. YMMV.

Plus at Hobbylinc the reload kits for the 24 mm motor run approx. $15 for 3 reloads, same as Estes D's these days and if I could burn a D or an F for the same price.... 29 mm loads around $10-12 each and up.

Many of the lighter 29 mm motored rockets are flown quite well on the 24mm version with an adapter. Many, many will say that they wished they'd built with a larger motor mount and used an adapter for smaller motors.
 

qquake2k

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I haven't bought one yet. I was hoping to learn how things worked so I know what to look for and what I'm talking about when I go to buy one. I don't even know what a BP motor is.

I used to launch rockets lots when I was a kid and have built many from scratch, even some cluster and multi stage cluster rockets.

I'm not a complete noob, I just got bored with store bought. I'm 47 now and would like to get past the toy store level. I'm looking at the different assosciations available in my area and have only found one (NAR) that doesn't fly anything past an E. Where does that regulation come from?
Instructions for Aerotech's RMS reloadable motors can be found on their website:
http://www.aerotech-rocketry.com/resources.aspx?id=4
 

hardinlw

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Nothing that big, I'm going to stick with 38 or smaller until I know what I'm doing.

So I would imagine these casings are multi-piece that screw together in sections and have small holes in each section to transfer ignition?

I don't want to get into electronics right now. And before I get that fancy, I'll probably try just a camera first.

Thanks!
The typical reloadable engine consists of a tube with forward and aft closures. There may be multiple propellent "grains" (cast segments) inside the tube, but there are no dividers. The composite propellent burns so slowly that almost all of the engines are core-burners to get sufficient burn area to produce reasonable thrust.

The aft closure is pretty much a threaded ring that holds the nozzle in place. It is usually larger in diameter than the engine casing and butts up against the back end of the motor tube to keep the engine from flying forward. For that reason, these rockets do not need an engine block and can thus use engines of different lengths.

The forward closure will usually have a cylindrical cavity where you install a smoke/delay element that is smaller in diameter than the propellent grains. This starts burning at the same time as the propellent. (Estes black powder engines were typically end-burners and lit the delay after the propellent was expended.) The top of the forward closure generally has an ejection well where you put the black powder ejection charge. There is a small hole connecting to the top of the delay cavity so that the ejection charge is ignited as the delay element burns through the top.
 
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