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Registered Member #902
Joined: Sun Jul 15 2007, 08:17PM
Location: Pacific Northwest USA
Posts: 1042
[sorry if this is considered thread jacking, I will make a new one if I have too] I recently started making my own motors, after years of my half mile G motor rockets, I wanted to expand my scope... One thing I found pretty interesting while trying to keep the fuel lit... I added some Yttrium metal [powder] and got it to light much easier... I start full static testing [with measurements] soon... and yes, I am using a thick walled engine casing, and I have a rocket nozzle mix from unitednuclear.com.... the pipe measures 5/8" I.D. and about 4" long... as a safety consideration, I will make the test holes in the nozzle get smaller as testing goes on until a reasonable amount of power is achieved without coming close to catastrophic failure... I am using a 60:40 ratio of KNO3 to Sugar... and the amount of yttrium has yet to be determined [BTW, I used yttrium instead of magnesium like suggested due to ease of availability without breaking down one of those blocks which I do not find efficient...] I also might experiment with some other additives I am using a remote electronic ignition system, the battery is a Husky Power Pack (I am not using the 120AC or the 12V lighter socket, but the jump starter) which runs through a control panel... the NiChrome ignites a fuse or if I have any at the launch time, I will use an aerotech copperhead igniter...
Registered Member #1083
Joined: Mon Oct 29 2007, 06:16PM
Location: Upland, California
Posts: 256
You could use a lot more propellant if you used the entire casement as the motor. Just make sure the tubing has a lapp weld or is seamless tubing. Butt weld tubing has a much lower pressure rating. It's also the most common type. For extra thrust, you could do the math and calculate and machine your own precision De Laval nozzle.
Registered Member #902
Joined: Sun Jul 15 2007, 08:17PM
Location: Pacific Northwest USA
Posts: 1042
Andyman wrote ...
You could use a lot more propellant if you used the entire casement as the motor. Just make sure the tubing has a lapp weld or is seamless tubing. Butt weld tubing has a much lower pressure rating. It's also the most common type. For extra thrust, you could do the math and calculate and machine your own precision De Laval nozzle.
there is a legal limit on propellant if I recall...
Registered Member #1438
Joined: Sat Apr 12 2008, 12:57AM
Location: Canada
Posts: 218
I would say that the 60/40 mix isnt the best to choose. I tried 70/30 mix which seems to work better (Expecially my cold and dry city)
I've tried coating the combustion tube with about a 2mm thick layer of KN03 grade black powder to let all the motor to be used at once (A very strong casing is usually needed). I also add a second motor on top connected by a 15 second fuse, so one the main motor runs out, the second motor comes online, seperating the main motor for maximum lift.
Registered Member #1630
Joined: Sat Aug 09 2008, 11:36AM
Location: Seoul Korea
Posts: 115
DaJJHman wrote ...
Andyman wrote ...
You could use a lot more propellant if you used the entire casement as the motor. Just make sure the tubing has a lapp weld or is seamless tubing. Butt weld tubing has a much lower pressure rating. It's also the most common type. For extra thrust, you could do the math and calculate and machine your own precision De Laval nozzle.
there is a legal limit on propellant if I recall...
Yes for store bought rocket engines there is a limit, and then you are in the high power class which requires a permit (special DOT class) . For homemade it's your own experimental propellant.
Registered Member #902
Joined: Sun Jul 15 2007, 08:17PM
Location: Pacific Northwest USA
Posts: 1042
Seoul_lasers wrote ...
DaJJHman wrote ...
Andyman wrote ...
You could use a lot more propellant if you used the entire casement as the motor. Just make sure the tubing has a lapp weld or is seamless tubing. Butt weld tubing has a much lower pressure rating. It's also the most common type. For extra thrust, you could do the math and calculate and machine your own precision De Laval nozzle.
there is a legal limit on propellant if I recall...
Yes for store bought rocket engines there is a limit, and then you are in the high power class which requires a permit (special DOT class) . For homemade it's your own experimental propellant.
not QUITE right, legally, without any form of permits, NO ONE may transport homemade rocket fuel based on what the BATFE deems an explosive micture (or store it, without an approved magazine), and the COMMERCIAL rockets do not really apply by the limits as they havethe licenses to make the fuel and do not even want to add too much or the engine will be more powerful than one wants, I was reffering to the MAKING of engines only... and unless there is some SERIOUS power in the enginges you buy commercially, normally you do not need a permit as they are commercially manufactured...
Registered Member #1630
Joined: Sat Aug 09 2008, 11:36AM
Location: Seoul Korea
Posts: 115
Well, not quite in Canada. Engines over size F are licencable and need a wavier from the ministry of energy and mines. G and greater are considered high power model rocket engines.
Homemade propellant is restricted by weight of fuel, but often they don't care as long as the rocket is intented to be tested in an area without airtraffic and that the conditions on the ground are such that there will not be a fire hazard.
Registered Member #1062
Joined: Tue Oct 16 2007, 02:01AM
Location:
Posts: 1529
Old thread =)
In the U.S its legal to make your own weapons (but you have to comply with other rules such as you can't pack gunpowder in enclosed spaces) but itls illegal to transport or sell them. Off topic but somewhat relavent (ile hijack my own thread if i want to =) ).
Registered Member #1630
Joined: Sat Aug 09 2008, 11:36AM
Location: Seoul Korea
Posts: 115
rp181 wrote ...
Old thread =)
In the U.S its legal to make your own weapons (but you have to comply with other rules such as you can't pack gunpowder in enclosed spaces) but itls illegal to transport or sell them. Off topic but somewhat relavent (ile hijack my own thread if i want to =) ).
No, it's not hijacking and perfectly relevaent to the discussion. Canada has quite different laws regarding firearms and explosives or here we are discussing(propellants). In Canada it is prohibited by law to make your own firearms unless you are given permission by a firearms officer and you cannot transport them unless a ATT is given (Authorization to transport) but propellants and some explosives maybe transported to and from a "worksite".
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