Level 1 Motors
For level 1 you are required to fly a rocket powered by an H or I class motor.
What is a Motor
A motor consist of a reusable casing and a reload kit which supplies the propellant for the motor to function, different compositions of oxidiser and fuel provide different thrust characteristics and or exhaust effects.
Were do I start
I suppose the first thing to consider in choosing a motor for Level 1 is whether to go with 29 mm or 38 mm motors. My choice is go with the 38mm Motors, why? Well if you look at the tables below you will see if you rocket has a 38mm motor mount you will have a much larger choice of motors, and you can always get a motor adaptor to fly on 29mm motors if you wished to.
Motor Manufacture’s
There are a number of manufacture’s who make motor cases suitable for level 1, I will cover the two which I believe are the most used in the UK, Areotech/Rouse Tech & Cesaroni
Areotech/Rouse Tech Case’s are supplied as a casing and two end closures, when you buy you reload kit you will get the propellant and the seals to complete the motor. The table below shows cases and the reloads suitable for Level 1 and their costs
No |
Rouse Tech |
Casing Cost |
Areotech |
Reload cost |
Total Motor Cost |
1 |
29/180 |
46.45 |
H128W |
17.45 |
63.90 |
2 |
29/180 |
46.45 |
H238T |
18.45 |
64.90 |
3 |
29/240 |
54.45 |
H97J |
21.95 |
76.40 |
4 |
29/240 |
54.45 |
H180W |
21.95 |
76.40 |
5 |
29/240 |
54.45 |
H220T |
23.95 |
78.40 |
6 |
29/360 |
61.45 |
I200w |
31.95 |
93.40 |
7 |
38/240 |
55.95 |
H73J |
21.95 |
77.90 |
8 |
38/240 |
55.95 |
H123W |
21.95 |
77.90 |
9 |
38/360 |
57.95 |
H112J |
30.95 |
88.90 |
10 |
38/360 |
57.95 |
I161W |
33.95 |
91.90 |
11 |
38/360 |
57.95 |
I357J |
36.95 |
94.90 |
12 |
38/480 |
64.95 |
I154J |
36.95 |
101.90 |
13 |
38/480 |
64.95 |
I211W |
39.95 |
104.90 |
14 |
38/480 |
64.95 |
I300T |
39.95 |
104.90 |
15 |
38/600 |
66.95 |
I195J |
41.95 |
108.90 |
16 |
38/600 |
66.95 |
I284W |
41.95 |
108.90 |
17 |
38/600 |
66.95 |
I435T |
45.95 |
112.90 |
Cesaroni Pro 38 Case’s are Cheaper than the Rouse Tech but you will also need a ProDat delay adjustment tool and this must be added to the cost of buying the motor. Cesaroni motors are undoubtedly the easiest to prep for flight. Again the table below shows cases and the reloads suitable for Level 1 and their costs
No |
Pro 38 |
Casing Cost |
Areotech |
Reload cost |
Total Motor Cost |
1 |
2G |
28.95 |
H153C |
28.95 |
57.90 |
2 |
|
28.95 |
H143.SS |
28.95 |
57.90 |
3 |
|
28.95 |
H400V |
29.95 |
58.90 |
4 |
3G |
33.95 |
I205C |
36.95 |
70.90 |
5 |
|
33.95 |
I212SS |
37.95 |
71.90 |
6 |
|
33.95 |
I566V |
37.95 |
71.90 |
7 |
4G |
39.95 |
I285C |
43.95 |
83.90 |
8 |
|
39.95 |
I287SS |
45.95 |
85.90 |
9 |
|
39.95 |
I800V |
44.95 |
84.90 |
|
ProDat |
12.95 |
|
|
|
From the tables above you can see that there is a wide selection of motors to choose from for your Level 1 Flight.
Not all of the above motors may be suitable for your rocket, before you chose your motor you will need to do a few calculations to ensure your rocket will be safe to fly and your motor choice is not underpowered therefore making your rocket unstable.
Thrust to Weight Ratio
As a guide your motor should always provide a thrust to weight ratio of 5:1
You can calculate the thrust to weight ratio of a motor by this simple equation:
Thrust to weight ratio = rocket weight X Ratio X 4.45
So to get find what motors you rocket can fly on you multiply your rockets weight by 5 then multiply the result by 4.45, this is the number of Newton's in a pound, this will give you the minimum average thrust for stable flight.
So if your rocket weights in at 4 Lb. then multiply it by 5 and then again by 4.45 you want and you'll get the average thrust of a motor. Any motor with an average thrust greater than the value you calculate should be suitable.
So 4lb x 5 = 20 x 4.45 = 89 therfore any motor with an average thrust of 89 newtons or more sould be suitable for this 4lb rocket.