Water rocket Parachute

 

Intro

Once our water rocket has been propelled into the sky it will need a way to stay as one, we have decided to put a parachute into our design to ensure the safety of the rocket allowing it to land on the ground after being launched. The parachute will be folded into the nose cone to be deployed after the rocket has reached its max altitude.

Research into shape design

To gain additional knowledge before testing materials and shapes we researched into pre-existing parachute design shapes.

Parachute types:

o Round

Round parachutes simply rely on drag to slow a descent, rather than having any lift, the dome-shaped canopies are not frequently used by modern jumpers due to their inability to steer and a low probability of a slow landing

o Cruciform

Cruciform parachutes provide a steady descent by reducing oscillation, This chute is rarely used outside of military manoeuvres

o Rogallo

Rogallo parachutes are used to increase forward speed while decreasing landing speed, this kind of chute has been heavily experimented on in the world of sport parachuting. A main disadvantage f this particular shaped design is the build difficulty.

o Ram air

The most modern parachute type is the Ram-air design, the self-inflating parafoils give the jumper greater control of speed and direction, while also being relatively robust by spreading the stress of being deployed each ‘run’. The two layers of fabric allow air to penetrate from vents in the front and form cells.

In conclusion, the best shaped parachute to meet the needs and requirements of the water rocket is the Round shaped chute. The round shaped chute provides a suitable landing technique, not allowing the rocket to travel further, the descent is vertical, while maintaining the ability to be pressed into a smaller shape to fit into the nose cone.

The design is reliable if made and designed from an appropriate material.

Research into water rocket kits

Kit 1

The cheaper version of our parachute kit will provide the buyer with:

· A list of appropriate household materials that can be easily used for the chute

· A template that can be downloaded and printed for the user to produce the parachute

Kit 2

This kit will be the most expensive out of the kits available, this particular kit will provide the buyer with:

· A premade parachute, tested and guaranteed to meet the needs of the user’s water rocket

· A downloadable template allowing the user to create their own chutes

Testing

Firstly, to determine what material to use for our parachute we needed to implement some small tests to see what material would be the most effective, we picked five household materials to test the velocity of the fall, damage taken to the object being propelled and the weight of the material.

 

Firstly, to determine what materials would work effectively as a parachute testing and research is needed. The following list provides advantages and disadvantages of household items that work well as a chute for a water rocket, as these materials will be provided as a list in both kits, they must be eco-friendly, cost-effective and easy to obtain. The Pre-made Parachute provided in kit 2 will be made of a material that is not as common in the household therefore will be priced higher while incorporating the labour price.

A PVC shopping bag

Advantages

· Cost-effective and easy to obtain

· Light-weight

· The material itself allows it to be folded and pressed down into a smaller space

· Partially weather resistant

Disadvantages

· The material is torn/ripped easily is it gets snagged on something

· Single use plastics are not eco-friendly and are hard to recycle

· The properties can change with time, due to plasticizer migration

A recycled cotton t shirt

Advantages

· Easy to obtain while being cheap and cost-effective

· Can withstand wear and tear

· Staple fibre traps air

Disadvantages

· Absorbent

· Poor elasticity

Paper/Card

Advantages

· Easy to obtain and cost effective

· Easy to machine into shaped

· Can fold/bend

· Reusable

· lightweight

Disadvantages

· Weather dependant

· May get deformed

A linen tea Towel

Advantages

· Strength

· Easy to machine into shapes

· Environmentally friendly

· Durable for reuse

Disadvantages

· Weight

· Liquid absorption rate is high

A recycled Polyester item

Advantages

· Strong

· Lightweight

· Wrinkle resistant

· Cost-effective

Disadvantages

· Designed for indoor use

Testing

To test these materials, we prototyped chutes with each one and recorded how they performed, we were looking for time taken to descend from a set height.

For a material to be applicable for use the speed of descent must be > 0.65s from the moment it is let go from the set height.

Material Descent time, s

PVC 0.96

Cotton 0.68

Paper/card 0.87

linen 0.73

polyester 0.79

These tests have shown that all of these 5 materials are suitable for use as parachutes as they all descended in the required time zone. Although some may be slower or faster than others, the user will have a wide variety if they choose to make their own parachute from our given template.

 

 

Pre-Made Parachute

The option to receive a pre-made parachute will be manufactured from Nylon.

Nylon is approximately £2.93 per square meter so is cost-effective in batch production, Nylon is versatile, has exceptional weather resistance, very strong, elastic and does not absorb water.

This Material is widely used in the larger scale Parachute production so we know that it is reliable and safe to use while meeting all of the requirements needed