Search found 187 matches
- Thu Dec 07, 2006 4:14 pm
- Forum: Rocket forum
- Topic: Physics xtra credit project: Build two 1-time-use candyrocks
- Replies: 29
- Views: 31671
Re: re: Physics xtra credit project: Build two 1-time-use ca
You will notice that almost all manufactured G motors have less than 62.5G of propellant (2 exceptions come to mind and they require a LEUP to own/use). Not true. ATF requires a LEUP for APCP propellants over 62.5 grams. Sugar motors, Hybrid motors, BP motors do not fall under this rule. I'm not su...
- Wed Dec 06, 2006 11:46 pm
- Forum: Rocket forum
- Topic: Physics xtra credit project: Build two 1-time-use candyrocks
- Replies: 29
- Views: 31671
re: Physics xtra credit project: Build two 1-time-use candyr
ISP will be down a bit for a 60/40 mix (fuel rich). Even if you assume an ISP of 100 you are in "H" class impulse.
Anything over 125g of propellant or 1500g liftoff weight needs a full waiver from the FAA.
Anything over 125g of propellant or 1500g liftoff weight needs a full waiver from the FAA.
- Wed Dec 06, 2006 7:58 pm
- Forum: Rocket forum
- Topic: Rocket parachute ejection
- Replies: 28
- Views: 37135
re: Rocket parachute ejection
Wondering how you'd keep the pin cocked in an acceleration rich environment? 10 g's is normal, 20 g's is common, 30 g's isn't unheard of...I've had flights in excess of 70 g's. Would take a pretty robust pin system to stay together. An ematch or christmas tree bulb etc, with a bit of black powder wo...
- Wed Dec 06, 2006 1:42 pm
- Forum: Rocket forum
- Topic: How Many Joules Through The Coil?
- Replies: 1
- Views: 5375
re: How Many Joules Through The Coil?
Estes has...minus the capacitor. BP is tough to make into a rocket motor. It needs to be very finely ground and packed at a high pressure. All of this makes it rather dangerous to do. Shocks aren't good for it, it can ignite. Once the motor is made there is a high likelihood that it'll have voids in...
- Thu Nov 30, 2006 2:16 am
- Forum: Off topic forum
- Topic: perchlorate cell
- Replies: 3
- Views: 4545
re: perchlorate cell
by perchlorate cell, do you mean a battery?
I can check with the two chemists that I know, but a bit more detail on the end game are in order...
Are you going for safety concerns?
How about suitability in the application?
I just don't know. PM me if you don't want the details public.
I can check with the two chemists that I know, but a bit more detail on the end game are in order...
Are you going for safety concerns?
How about suitability in the application?
I just don't know. PM me if you don't want the details public.
- Wed Nov 22, 2006 6:27 pm
- Forum: Rocket forum
- Topic: Nozzle Question
- Replies: 11
- Views: 12656
re: Nozzle Question
Copper doesn't work well as a nozzle, it melts at too low of a temp.
Its a bitch to machine too...sticky and work hardens very quickly.
If you want a green flame, barium nitrate is what you want...careful, its toxic.
Copper will give you a blue flame.
Its a bitch to machine too...sticky and work hardens very quickly.
If you want a green flame, barium nitrate is what you want...careful, its toxic.
Copper will give you a blue flame.
- Wed Nov 22, 2006 5:58 pm
- Forum: Rocket forum
- Topic: Nozzle Question
- Replies: 11
- Views: 12656
re: Nozzle Question
I've seen them work with solids...if you do it right, there aren't a lot of solids in the exhaust.
- Sat Nov 18, 2006 4:07 pm
- Forum: Rocket forum
- Topic: 1st Static test
- Replies: 5
- Views: 8706
re: 1st Static test
It had the right sound for a sugar motor...
So share the details, like Greg ask...Interested minds want to know.
So share the details, like Greg ask...Interested minds want to know.
- Sat Nov 18, 2006 1:07 am
- Forum: Rocket forum
- Topic: Rocket calc ?'s
- Replies: 16
- Views: 16955
re: Rocket calc ?'s
The formula seems OK, but particle sizes aren't listed. Particle size is critical to the mix... I would stay away from the Mg though. Its tougher to get, and it can be a bit nasty to work with in small particle sizes. You can use aluminum instead. Whether you use Mg or Al, remember to wet the metals...
- Fri Nov 17, 2006 8:16 pm
- Forum: Rocket forum
- Topic: Rocket calc ?'s
- Replies: 16
- Views: 16955
re: Rocket calc ?'s
The mesh size is going to be dependent on the oxidizer...and the effect you are going for. I work with AP most often, so I'll speak from that perspective, I am most familiar with it. I think the finest I would go on AP would be around 60 micron. Most of the stuff I've done is with 200 micron, but yo...
- Fri Nov 17, 2006 4:31 pm
- Forum: Rocket forum
- Topic: Rocket calc ?'s
- Replies: 16
- Views: 16955
re: Rocket calc ?'s
Get the biggest scale you can afford. I have a 4000g 0.1g resolution Ohous digital balance. I also have a 7000g 1g resolution generic scale. The Ohous was expensive the generic scale was not. I use the fine balance for the small value measurements, and the generic scale for the bulk items (AP in par...
- Fri Nov 17, 2006 1:58 am
- Forum: Rocket forum
- Topic: Rocket calc ?'s
- Replies: 16
- Views: 16955
re: Rocket calc ?'s
Re-reading this I realized that I didn't answer some of the questions you ask...so here goes. The altitude you get with the sugar motor on your rocket should be better than the estes BP motor, and should be less than your Aerotech reload. The ISP of the BP is lower than the sugar motor, but the suga...
- Fri Nov 17, 2006 12:06 am
- Forum: Rocket forum
- Topic: Rocket calc ?'s
- Replies: 16
- Views: 16955
re: Rocket calc ?'s
Another way you can approach it is to burn some motors at pressures you believe will be "safe", be very conservative. Measure the internal pressures, and burn times. Plug the numbers into the spreadsheet from the OTHER book you bought (McCreary) and you'll get an approximation of the a, n and Isp* v...
- Thu Nov 16, 2006 11:13 pm
- Forum: Rocket forum
- Topic: Rocket calc ?'s
- Replies: 16
- Views: 16955
re: Rocket calc ?'s
Sorry, updated my previous post...added some things...
I've managed to push one of my rockets (26 lbs) to 14,631 ft on a motor I've built. It was a 5 grain 75mm APCP motor.
A couple of my friends have gotten about the same altitude with some of the motors I've built.
I've managed to push one of my rockets (26 lbs) to 14,631 ft on a motor I've built. It was a 5 grain 75mm APCP motor.
A couple of my friends have gotten about the same altitude with some of the motors I've built.
- Thu Nov 16, 2006 10:52 pm
- Forum: Rocket forum
- Topic: Rocket calc ?'s
- Replies: 16
- Views: 16955
re: Rocket calc ?'s
There really isn't a good way to guess on the burn rate in a motor. As far as I know the only way to find out burn rate is to burn a motor, time it with reasonable accuracy, then calculate it based on web thickness. You want to do it in a ballistic motor for the greatest accuracy, for even better ac...