Thread: High Power Rockets

Originally Posted by Phrank

Welcome to the forum!

Sheesh, and I thought I was a poet trapped in the body of a wrestler at 6'4"...me and some friends used to hack around with the rocket kits, smaller one with the D engines, they were an awful lot of fun!

So is the launch area free of airplane routes or do you have to let the local airports know you're launching...I remember we had to if we had any rockets that could get up above certain level.

It all starts with the small rockets... the first one is free so to speak. An Estes D engine has about 20 ns (Newton Seconds) of total impulse. This motor has 35,000ns of total impulse. Yes the launch area is free of airplanes and no where near commercial routes. We work closely with the FAA to get permission to fly. Smaller rocket launches will get a Waiver from the FAA and a NOTAM is posted inform pilots in the area of the activity that is going on. This launch is able to get the airspace restricted and as such, air traffic will be diverted around the area if need be. But at the end of the day, if you can see a plane or there is cloud cover to prevent you from seeing planes, you simply do not fly.

Originally Posted by Tripoli3

No, AP is has a very consistent burn rate but you do have to characterize every formula for burn rate vs pressure. AP is what the shuttle used. Yes I do use metals as well. AL and Mg in this case but fairly low percentages. You may be confusing AP with potassium perchlorate.

I had to check some papers, we used it with different catalysts and at pressures no one wants in a rocket, but then it "stepped" thru about 20 different levels of deflagration and ended up at full detonation.
For us it wasn't of any practical use, more of a curiosity, I just helped when they tried some new stuff out.

Found this old doc on burn rate for AP, not sure if it covers the "jumps" but it was good enough to be my night reading;

www.dtic.mil/dtic/tr/fulltext/u2/688944.pdf

Originally Posted by Tripoli3

No, AP is has a very consistent burn rate but you do have to characterize every formula for burn rate vs pressure. AP is what the shuttle used. Yes I do use metals as well. AL and Mg in this case but fairly low percentages. You may be confusing AP with potassium perchlorate.

Could very well be...was a long time ago, you built the rockets, you could get the single, double or even triple staged rockets, and the engines were solid propellant. The last one we used was a three stager, went up and just disappeared. It had a shute, but the thing just went, "zip" straight up and was gone!! The others we could at least hear the small pop as the chute was deployed and find the rocket in the adjoining field. That was like 25 years ago...lots of fun!!!

Originally Posted by Lemur

I had to check some papers, we used it with different catalysts and at pressures no one wants in a rocket, but then it "stepped" thru about 20 different levels of deflagration and ended up at full detonation.
For us it wasn't of any practical use, more of a curiosity, I just helped when they tried some new stuff out.

Found this old doc on burn rate for AP, not sure if it covers the "jumps" but it was good enough to be my night reading;

www.dtic.mil/dtic/tr/fulltext/u2/688944.pdf

Thank you! I have not read that paper so I am looking forward to it. Just in a quick skim it does not cover HTPB but does cover PBAN which is used in the hobby. Interesting research you got to do. Up until the PEPCON accident it was not thought that AP could detonate unaccelerated. There was quite a bit of research after that funded to find out how that accident could happen.

Jeeze, I can't even make scales correctly..... much less a rocket....

Yes, that paper was fun, they are on the right track and can see something is going on.
Ammonium nitrate also has those "steps", perhaps it's the breaking up of the Ammonia part that messes with the enthalpy.
I know Fluoride (as in Teflon) in rocket engines can speed them up but they are a mess when you try to figure them out.

I worked with explosives mainly but rocket fuel sometimes overlap, mostly by accident!

Play safe and post more rocket stuff, they sure are fun!

Originally Posted by Wintchase

Jeeze, I can't even make scales correctly..... much less a rocket....

Thanks!!! Needed that...that was truly a coffee through the nose experience!!!

Originally Posted by Tripoli3

Yes this was at Balls.. top two are Balls 2009.. Bottom one is from Balls 2011 when it flew for the Carmack 100k challenge. I built this rocket again and had it at Balls this year as well but was unable to fly it due to my GPS transmitter failed so I would not be able to recover it with a predicted altitude North of 100,000 ft AGL. The rocket is a clone of a Super Loki Dart with 36 lbs of propellant in it. The propellant is APCP (Ammonium Perchlorate Composite Propellant) Ammonium Perchlorate is the oxidizer, HTPB (Hydroxyl-terminated polybutadiene) is the binder. It is a room temperature curable liquid rubber along with a few other ingredients to adjust the burn characteristics and physical properties of the finished propellant. Yes the rockets are fully recoverable. I'll fly this rocket next at Balls this year. Balls is the name of one event where people go to fly these rockets, the club works with the FAA to secure the airspace and have permission to fly these rockets.

I fly hybrids. I like the "additional" challenge and lesser fuel cost. Granted the Ground support equipment is a larger upfront...and keeping the Nitrous at proper temp/pressure is a challenge but a friend and I put together and insulated jacket, temp sensor and peltier device to heat/cool the tank as necessary for proper operating pressures for the oxidizer. Of course visiblity of the vent plume is a challenge in very dry environments so another circuit board there and thermistor to detect the temp drop of the "tank is full" plume. Mid summer launches or dead of winter are non issues now.

I crashed my last "big" rocket. It went land shark, and deployed its drogue at apogee of about 3000' (and 700 fps) and shredded. I looked for it 3 days running in the plane before I found it. The only loss were the chutes and airframe!

Do you ever go to Plaster Blaster? 25K waiver there...

Originally Posted by Splashone

I fly hybrids. I like the "additional" challenge and lesser fuel cost. Granted the Ground support equipment is a larger upfront...and keeping the Nitrous at proper temp/pressure is a challenge but a friend and I put together and insulated jacket, temp sensor and peltier device to heat/cool the tank as necessary for proper operating pressures for the oxidizer. Of course visiblity of the vent plume is a challenge in very dry environments so another circuit board there and thermistor to detect the temp drop of the "tank is full" plume. Mid summer launches or dead of winter are non issues now.

I crashed my last "big" rocket. It went land shark, and deployed its drogue at apogee of about 3000' (and 700 fps) and shredded. I looked for it 3 days running in the plane before I found it. The only loss were the chutes and airframe!

Do you ever go to Plaster Blaster? 25K waiver there...

I don't fly Hybrids anymore but have in the past. I still have a Ratt I80 laying around that I have not flown in years. I did certify L3 with a Hypertech M in 2003. In fact.. here is a video of it:



I fly mainly at Blackrock as it is only a 4 hour drive. Short by Blackrock standards. I sometimes go down to Dairyaire and have done ROC launches a few times the last being LDRS when it was in Vegas. Balls is the one launch I never miss since I exclusively fly EX anymore due toe the cost savings. I can make a M for ~$35.

What a great thread. My son and I always have an Estes model in progress, and we've started into scratch builds. We haven't attended a high-powered launch yet.