# 57300 Motor Documentation

[ToC]

## Overviews


### Revision

#### V1

- Minimal design
- Nozzle
- Lid
- Tube
- Propellent

### Parameters

- Peak Pressure: 1.89MPa
- Total Impuse: 1264Ns
- ISP: 110.24s
- Classification: J
- Peak Thrust: 370N

## Nozzle


### Parameters

- Material: Stainless Steel
- Throat Diameter: 14mm
- Exit Diameter: 28mm
- Convergence Half Angle: 60°
- Divergence Half Angle: 15°
- O-Ring: AS568-033 FKM
- Fixed by 4 M4 12.9 metric coarse pitch thread

### Saftey

Nozzle's Area

$$
A = ((\frac{57mm}{2})^2\cdot\pi) - ((\frac{14mm}{2})^2\cdot\pi) = 2.3978 \times 10^{-3} m^2
$$

Force on the nozzle

$$
F_{nozzle} = P \cdot A = 1.89MPa \cdot 2.3978 \times 10^{-3} m^2 = 4531.84N
$$

#### Bolt Saftey Factor

M4 12.9 Shear Proof Load

$$
F_p = 8520N \\
F_{p\tau} = Fp \cdot 0.57 = 4856.4N
$$

Using 4 M4 12.9 screws

$$
SF = 4 \cdot F_{p\tau}/F_{nozzle} = 19425.6N/4531.84N = 4.28
$$

## Lid

### Parameters

- Material: Stainless Steel
- Thickness: 15mm
- Diameter: 57mm
- O-Ring: AS568-033 FKM
- Fixed by 5 M4 12.9 metric coarse pitch thread

### Saftey

Lid's Area

$$
A = ((\frac{57mm}{2})^2\cdot\pi) = 2.5517 \times 10^{-3} m^2
$$

Force on the lid

$$
F_{lid} = P \cdot A = 1.89MPa \cdot 2.5517 \times 10^{-3} m^2 = 4822.71N
$$

#### Bolt Saftey Factor

M4 12.9 Shear Proof Load

$$
F_p = 8520N \\
F_{p\tau} = Fp \cdot 0.57 = 4856.4N
$$

Using 5 M4 12.9 screws

$$
SF = 5 \cdot F_{p\tau}/F_{lid} = 24282N/4822.71N = 5.03
$$

## Tube

### Parameters

- Material: 6061 aluminum alloy tube
- Tube Length: 300mm**
- Burning Grain Length: 300mm
- Thickness: 3.15mm
- Inside Diameter: 57.2mm
- Outside Diameter: 63.5mm

### Saftey

#### Barlow's formula

$$
P = \frac{2\sigma_{\theta} s}{D}
$$

- $P$ Internal Pressure
- $\sigma_{\theta}$ Allowable stress
- $s$ Wall thickness
- $D$ Outside diameter

#### Saftey Factor

6061 aluminum alloy 3mm thick tube has yield tensile strength $F_{ty}=16ksi\approx 110.31MPa$

$$
P = \frac{2 \cdot 110.31MPa \cdot 3.15mm}{63.5mm} = 10.94MPa
$$

$$
SF = P / P_{peak} = 10.94MPa/1.89MPa = 5.78
$$

## Grains


### Parameters (Pre Grain)

- Propellant: KNSB (65wt% KNO3 35wt% sorbitol)
- Port Diameter: 20mm
- Port Offset: 18mm
- Segment Length: 150mm
- Quantity of grain: 2
- Total length: 300mm
- Grain Diameter: 57mm

### Area Graph


### Manufacturing Process

## Reference

- MIL-HDBK-5H: https://ssrl-uark.com/MILHDBK5H.pdf
- Rocket motor classification: https://en.wikipedia.org/wiki/Model_rocket_motor_classification
- O-Ring Spec: https://www.yuenchin.com/uploads/catalog/5ebea0601e9d2fe060ced486833820b0.pdf
- ISO 898-1: http://fpg-co.com/Standards/ISO898-1.pdf