What exactly is “High Power Model Rocketry”?

In the broadest of definitions used today, means rockets powered by motors more powerful than “D” type motors. For years, the Estes D12 was the most powerful motor most people could purchase. With the advent of propellants more powerful than black powder, new E, F, and G type motors appeared. We generally use the term “high power model rocketry” to describe E, F, and G powered models weighing less than 3.3 lbs. High power model rockets do not require special licenses or permits to be flown legally. Due to the rise in popularity of H, I and J powered rockets, this class is often referred to as “mid-power rocketry” as well.

How high do they go?

Below is a range of possible altitudes, depending on the motor type used and the lift-off weight of the model:

D12 250’- 1,200’
E15 350’- 2,700’
F30 500’- 3,500’
G50 500’- 4,500’

How fast do they go?

Well designed high power model rockets are capable of speeds in excess of the speed of sound (that is, greater than 600 mph). However, typical flights are in the 200-500 mph range.

How much does it cost?

Surprisingly, high power model rocketry is not that expensive.  Most kits can run between $60 and $120, depending on the complexity of the kit. Launch support equipment can costs about  $100. The biggest cost that jumps out at people is the cost per flight.  The cost per flight can be from $15 to $25 per flight for F to G type motors.  When you compare the power and price to Estes engines, you’ll see that the cost is comparable  (cost per Newton-second of impulse). In terms of delivered power , the high power rocket motors are no more expensive than black powder motors.

Are the kits hard to build?

If you have experience building Estes kits, you will find that most high power rocket kits are not difficult to construct. The biggest differences between North Coast Rocketry kits and Estes kits are the materials used. Typical differences are illustrated below:

Component Estes North Coast
Body Tube thin paper tube thick paper tube
Fins balsa plywood
Centering Rings paper plywood
Parachutes plastic nylon cloth
Shock Cord rubber elastic
Shock Cord Mount paper steel cable
Adhesive white glue/CA epoxy

Other than the material differences, the assembly, operation and use of NCR rockets is similar to Estes rockets.

What is a composite rocket motor?

A composite rocket motor is a rocket motor that uses a “composite” propellant, rather than the “black powder” propellant commonly found in Estes engines. Composite motors, as a rule of thumb, are considerably more powerful when the same weight of propellant is used. They use the same technology as modern solid rocket motors.

What is composite propellant?

Composite propellant is an advanced rocket propellant formulation currently used in most solid propulsion rocketry and missile systems today. It is called a composite because it combines a solid fuel with an oxidizer in a rubber binder. This is radically different than black powder, which is a loose powder that is rammed under high pressure to become a solid grain.

How are composite motors different than black powder motors?

Composite motors use a more powerful propellant than black powder. The comparative measure of power is called specific impulse. Composite propellants have a specific impulse nearly three times greater than black powder, ounce for ounce.

How are rocket motors classified?

Motors that can be sold to the general public, without the need for specialized tests or a license are called “model rocket motors”. Rocket motors are classified in a manner that assigns a letter prefix to the motor designation to indicate the power class of the engine. Each class can be twice as powerful as the class before it. The measure of power for each motor is called “total impulse” and is the measurement of force over time. Because model rocket motors use the metric system, the measure of total impulse is in Newton-seconds. The current model rocket motor classes are:

 Type  Total Impulse (Power)
1/4A  0-0.625 n-sec
1/2A 0.626-1.25 n-sec
1.26-2.50 n-sec
2.51-5.00 n-sec
C 5.01-10.00 n-sec
D 10.01-20.00 n-sec
E 20.01-40.00 n-sec
F 40.01-80.00 n-sec
G 80.01-160.00 n-sec

(Rocket motor types larger than G are restricted in their sale and use)

What are the requirements to fly high power model rockets?

There are no special licenses required to fly rockets up to and including G power provided that you follow the  National Association of Rocketry (NAR) Safety Code. Modelers need to be 18 years or older to purchase G motors nationwide. California is more restrictive, requiring purchases for F motors to 18 or older as well.

Is high power model rocketry safe?

One of the things that model rocket enthusiasts are most proud of is the hobby’s outstanding safety record. Since the inception of model rocketry in 1957, there has never been a fatal accident, despite over 600 million rocket flights!  That is a much better track record than football, biking, fishing, golf, or many other recreational activities. The NAR conducted an in-depth study of the safety of high power model rocketry before approving increases in liftoff weight and propellant masses.  Additionally, there have been independent assessments by government consultants that have also concluded that high power model rockets are indeed safe.

What kind of equipment do I need?

Generally, high power rockets are larger and heavier than A-D powered model rockets.  As a result they require larger,  more robust launch pads.  For high power model rockets, a 1/4” diameter launch rod is suggested, preferably 5’ long. Do not attempt to use the small Estes Porta-pad or similar launcher!  The small size will not support the rocket properly: a fact you’re sure to learn the first time the breeze blows the launch pad and the rocket over! Also, your high power rocket will require a launch controller with longer wires. The Safety Code is pretty specific about the lengths; for models E power or greater, leads of 30’ are required.  There is an additional benefit to this distance;  the farther back you are, the easier it is to see and follow the rocket during its flight.

What kind of flying field do I need?

As a good rule of thumb, you should find a flying field at least 1,000 feet square, without building, trees, power lines, roads, etc. across it.  Most of the North Coast kits do not drift as far as Estes rockets (due to their higher weight), so field size for rockets up to G power  is not as important as it may seem.  In a pinch, a large, open athletic  field can be used for E and F powered flights. We would suggest that the field be as long and as wide as the expected altitude of the rocket. So,  for 1500’ flights, the field should be at least 1500’ square or larger.

What about weight limitations?

The Federal Aviation Administration (FAA) regulates the way that we fly our rockets. Currently, if you  fly a rocket that complies with the following conditions:

  • It weighs 53 ounces (1500 grams) or less;
  • It contains less than 4 ounces (113 grams) of propellant;
  • It uses a motor certified by the NAR;

Then there are no restrictions on your flights. These are called “model rockets” in the FAA regulations and are unrestricted, provided that you follow local regulations and the safety code.