How High Do Model Rockets Go? Guide to Engine Types

Model rocket surrounded by smoke with fire shooting out of the bottom just before takeoff.

Model rockets are fascinating to children and adults of any age. If you’re looking to get started with model rockets, you probably have a few questions about how they work and the heights they can achieve.

How high do model rockets go? The answer depends on a couple of factors: the weight of your rocket and the motor you’re using. Motors are commonly black powder engines that range in class from A to F. Each class is two times as powerful as the one before it. The more powerful the engine you have, the higher your rocket will be able to go.

Are you looking for a couple of beginner model rocket recommendations and an easy-to-understand explanation of engines and their power? Let’s get started.

What Are Some Examples of Beginner Model Rockets and Heights?

It’s important to start out with a simple rocket that’s easy to construct. You should use something with a basic motor while you are still learning about them.

Here are a couple of recommended beginner rockets that are easy to use.

Estes 1491 Taser Rocket Launch Set

Estes 1491 Taser Rocket Launch Set,Brown/A

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This model rocket is recommended for beginners because it’s easy to build and launch. It takes about an hour to assemble, not including time for the glue to dry. 

How high will it reach? That depends on the motor.

This model doesn’t come with an engine, so you will get to decide which one you want. With a C6-5 engine, this model rocket can reach an altitude of about 1,100 feet (335 meters).

Recommended engines for this model are:

  • A8-3
  • B4-4
  • B6-4
  • C6-5
  • C6-7

If you’re brand new to model rockets, it’s probably best for you to start off with the weakest engine. The Estes A8-3 Engine Pack is a good place to start.

It’s a 3-pack, so you can practice using it several times, and it allows you to try again if something goes wrong.

Apogee Apprentice

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This model rocket is listed as a skill level 1, so it’s guaranteed to be simple to use for beginners.

The rocket only weighs 1 ounce (28.35 grams), so most engines will be able to work with it.

Some engines have weight limits, especially if they are low powered, so it’s something you should pay attention to so the rocket and engine will function correctly.

The engine power will determine how high the rocket will go.

This chart shows the estimated height an engine will propel the Apogee Apprentice model rocket.

Engine Engine Manufacturer Engine Size (mm) Altitude




1/2A3-2T Estes 13 87 27
1/2A6-2 Estes 18 69 21
A3-4 Quest 18 247 75
A3-4T Estes 13 274 84
A8-3 Estes 18 240 73
A10-3T Estes 13 273 83
B4-4 Estes 18 606 185
B4-4 Quest 18 716 218
B4-6 Quest 18 716 218
B6-4 Estes 18 635 194
B6-6 Estes 18 635 194
C6-7 Estes 18 1,455 443

This chart lists two different sizes of engines: 13 mm and 18 mm. You can buy an adapter to fit the 13-mm engine in an 18-mm casing.

This can be pretty useful if you’re only able to find 13-mm engines and you have an 18-mm rocket. 

Be sure to read about my other model rocket recommendations for more advice for beginners.

What Are the Different Classes of Model Rocket Engines and What Do the Letters Mean?

The engine numbers can seem a little confusing at first. Surely “A8-3” means something, right? Turns out, it does.

This section will go into full detail because it can seem a little complicated at first.

Here’s a super simple chart you can refer back to later:

A 8 3
Power Rating Average Thrust   Delay Time
Size of the fuel tank How fast it burns up inside, or speed   When the parachute ejects (measured in seconds)

Power Rating

The power rating is the first letter in the engine number. The letters range from A to F.

A is the least powerful and F is the most powerful.

The power of each rating is twice the size of the letter before it. So, one C engine has the power of two B engines or four A engines.

What exactly is a power rating, and what does it do?

The power rating determines the altitude that your rocket will be able to reach.

So, a C engine will be able to go higher than an A engine. It’s like a gas tank. The more fuel you have, the further you’re able to drive.

It’s possible for an engine to be smaller than A. You might see engines that are labeled as 1/2A, 1/4A, or 1/8A.

Those are just fractions, meaning that the 1/2A has half the amount of power as the typical A engine. 

Earlier it was mentioned that they’re labeled A to F, but that’s not entirely true.

A through F are the most common rocket sizes used for model rockets, but, if you have the money and space, there are engines that are labeled with a P!

That would take about 32,000 A-sized engines and will cost hundreds of dollars. 

Average Thrust

The number following the letter determines the average thrust. In the chart, this number is the 8 in A8-3.

The easiest way to understand this is to think of it as the speed it goes up into the air.

In the first chart, notice that there is a B4 and a B6 engine. B means they have the same power (or altitude), so they will go about the same height in the air.

The key word is “about.” The B4 engine is faster than the B6 engine, so the B4 will go slightly higher.

How so? It’s because of something called drag force. It’s a pretty technical concept, so the best way to understand it is with a visual.

Imagine you have two carts.

One has old wheels, but the other has new wheels that allow it to go about twice the speed of the old cart. However, the cart with the new wheels is filled with bricks.

The weight of the bricks will cause the cart to slow down because of the weight. The cart with the old wheels will be able to catch up to the new cart because it’s not weighed down.

The B4 and B6 engines don’t exactly work this way because the drag force is about force and not weight, but the visual does give an idea of what makes the two engines different.

Delay Time

The delay time is the number that comes after the dash.

This number determines when the parachute will be released. So, in the A8-3 engine, there will be a delay of 3 seconds.

The delay is measured from the time the propellant inside the engine is completely burned up and stops thrusting the rocket upwards to when the ejection charge is activated.

You don’t want to release the parachute while the rocket is still being forced upwards because the speed and force will cause the parachute cords to rip off the rocket.

You might never see your rocket again!

If you have a powerful rocket that has a rather large average thrust, say, a B4 or C6 engine, you will want a long delay because it takes some time for the rockets to slow down if they had a lot of power boosting them into the sky.

The A8-3 engine has a short delay because A means low power and 8 is a relatively slow average thrust.

Wrapping It Up: Which Engine Should I Get?

Now that you have some model rocket recommendations and a basic understanding of engines, you can put your knowledge to work.

The engine you should get depends on what you’re looking for. 

If you want the rocket to reach high altitudes, you’ll want a C or higher engine. If you want the rocket to have speed, the average thrust number should be small.

Remember that smaller delay times are good for smaller engines and the bigger delay times are good for bigger engines. 

One final note: make sure you have sufficient space to use your rocket. Powerful engines with large average thrusts mean it might travel quite the distance on its way down. 

Last update on 2023-05-31 at 05:18 / Affiliate links / Images from Amazon Product Advertising API

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I'm a hobby enthusiast with a real love for painting miniatures. I also happen to run this site and write the majority of its content!