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Burn rate isn't really an open air/enclosed type of question. Its actually very dependent on several items...one of them being pressure, so your equation ends up being recursive. The math for burn rate is below. Burn rate = c+ap^n but can be simplified to burn rate=ap^n, it gives a close approximati...

The epoxy reaction is an exothermic one, as you have found out. Nothing went wrong, the faster curing epoxies will naturally generate the heat in a shorter period of time. When you concentrate the heat by placing it in a cup or "confined area" it will heat much faster, there just isn't the surface a...

as far as I know they do allow sugar motors at their launches...I've been to several where they have launched sugar motors... I saw a large percentage of them CATO on the pad...somthing about cracked grains...You shouldn't store sugar grains for very long...I have heard about guys sealing them up in...

I'll check with some of my buddies to find if there is a simple way to test for KNO3... In the mean time, check the side of the container, if it says it contains Potasium Nitrate, its most likely ALL KNO3...virtually all of the brands that I have looked at are fairly high purity, not lab grade, 98% ...

Let me add just a few things. I keep hearing people say that rocket propellant is low energy (rocket candy in particular). Rocket propellant *is* low energy when compared to other energetic chemistry mixtures...Burn rate is the defining factor. Rocket propellants burn at less than 1ips, while thing...

Much better, read the sticky...start with Nakka's page...

All the stuff you want is there.

well if you combine wood and Oxegen you'll get fire...careful, you can get burned. combine charcoal brickettes, lighter fluid and atmoshperic oxegen you can get steaks...careful, you can get blocked arteries from this mixture... Combine coffee and steamed milk, you'll get a latte'. Careful contents ...

In model rocketry, there isn't such a thing as an optimal L/D ratio...I've seen rockets that are very very long for their diameter and rockets that are very, very short for their diameter...in fact, I've flow both. CG must be at least one body diameter in front of CP, except when it doesn't have to ...

well, in general, given a "standard" core, the length is about 1.5 times the diameter.

You don't have to be precise, 1.5 times will get you close. If you model the motor in BurnSim or a spreadsheet from Nakka (on his D/L page) you can tweek to make a neutral burn profile.

It was an amazing trip. 30 hours of drive time over 4 days with 3 good friends. I had several motors prepared for this event. A 6 grain 75mm "M" class motor 2-5 grain 75mm "M" class motors a 2 grain 75mm "L" motor and a 7 grain 54mm "L" motor. All of them burned flawlessly. I started flying with a c...

This is about as simple as you can get...works fine for small motors. It only requires some lumber and a video camera.

Good luck.

The vent hole is very small, the injector inside the combustion chamber is larger. You fill until the nitrous tank is full of liquid. The small vent at the top will vent gas until the tank is full. Nitrous self pressurizes, the gas at the top will push the liquid nitrous into the combustion chamber,...

OK, now it seems like you are getting upset. I am trying to help. Ask what you mean, you'll get answers you can use. You ask about a purge valve, its common nomenclature around the flight line that this means the solenoid that dumps the tank in the event of a misfire. Its part of the GSE. The vent h...

Sorry, lost track of the conversation

Pratt Hobbies has a full launch control system for hybrids.

GSE for hybrids is expensive...get ready for the sticker shock. They can be built cheaper, I think he even has the requirments on his website.

its not really a valve. Its just a bulkhead that has been drilled through, tapped for a pipe fitting and installed in the center of the motor, above the fuel grain. A fill hose is attached, the motor is filled on the pad, ignitor is fired, fill hose burns through and the nitrous starts to flow into ...