I don't know the entire history of reloadable motors, heck I'm not even sure if they should be called motors or engines. But they are one of the things that got me interested in the hobby again, and there are a lot of questions about them. So for anyone who isn't familiar with reloadable I'm going to share my experiences.
The basic reloadable casing consists of a casing, a forward closure, and an aft closure. The casing is filled with fuel, a cardboard liner, and sometimes a cardboard spacer. The forward closure is filled with delay material and a small container of loose black poweder snaps onto the top for ejection. The aft closure then holds a nozzle on. Throw in a bunch of O rings to seal the whole thing up and you have a reload!
The problems with RMS are mainly with the ejection charge. I've heard many complains that the charges are too large and come too late. Some people are even known to "trim" their delay element to shorten the time before their chute ejects. I don't see anything wrong with this, but it is against the saftey rules (No modification of engines. Many people apparently also feel the need to remove some of the BP from the actual charge espically when using rockets smaller than the largest body tube the casing is normaly used with.
I'm happy with my system. I currently have a 24/40 casing and closures, and a 29/240 casing and closures. By the way, that first number is the diameter of the casing in milimeters the second number is the maximum thrust the casing is rated for. With the 24mm system you can use anything from D through F engines, very nice for getting a little extra power into your Estes D kits. The 29mm system uses reloads E through G for those larger models.
US Rockets have their own line of "reusable" motors, but I have no experience with them. I'm looking forward to them coming back into production and based on the conversations I've heard on R.M.R they are probably a lot like the Kosdon reloadables.
The USR reloadables appear to be available in higher thrusts in even the smaller sizes. This and their "firestarter" propelent have me really excited. I plan on trying their system out as soon as I can afford it. I'll update this when I know more!
The Kosdon reloadables look nice. The price on reloads is lower than Aerotech reloads, but there are a few catches. Kosdon dosen't include igniters (Not that copperheads count) or an ejection charge. Also the Kosdon casing requires a pair of snap ring pliers to assemble. Finally there are allegations that the Kosdon design was stolen from US Rockets a few years ago. I don't like getting into the politics of any hobby but it sounds like a nasy situation I don't want to get into.
Becuase of the special tools, and things that aren't included I'm not that inclined to try Kosdon reloads. They also don't offer nearly the range of reloads that US Rockets will once they are back in production.
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Jason Hitesman
All text, images, ideas, and whatknot © 1996 Jason Hitesman