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Apogee is important

Why is apogee important in model rockets? Apogee is pivotal in the timing of the deployment of the parachute which allows the rocket to find its way to the ground safely, without damaging the rocket or the devices inside it. Timely parachute deployment from apogee ensures that the parachute will not tear mid-flight, so the rocket will be easier to track by eye on its way to the ground; this way fewer rockets will be lost on their way down from a flight. Late or early parachute deployment results in net forces acting against the parachute (in addition to the force of gravity it already has to act against) in flight, causing a larger strain on the parachute and rocket frame. In relation to the rocket apogee, a one second difference in the deployment of a parachute translates roughly to a change in 32 feet/second in velocity. While it is possible to create rockets and even possibly parachutes that can withstand theses forces, it is ideal to minimize these stresses wherever possible. These extra forces can cause rips and tears to less hardy parachutes or damage to the rocket frame, causing the rocket to plummet downwards rather than parachuting slowly down. Without optimal parachute deployment, the recovery stage of the rocket’s flight will fail. Exploring rocket apogee detection methods, and in particular the use of the Kalman filter in rocket apogee detection, helps optimize performance while minimizing costs and disadvantages.

Current mechanical methods

Current methods used to deploy the parachute are completely mechanical and are not completely electronic. The most often used method as well as the most primitive method of deploying the parachute is to make use of a second ignition to push the components of the rocket out and towards the nosecone. The maker of the model rocket will usually drill a hole into a tube, and pack a certain amount of charge powder (the amount depending on the length and area of the hole). After the thrust and consequent burnout of the rocket engine, the last of the burnout sets a second ignition that blasts the charge up the body tube towards the nosecone. The force of the blast splits the rocket and sends the parachute components out into the air to catch wind resistance. The recovery wadding (Figure 1) must be placed in order to protect the parachute from the explosive charge. As seen in Figure 3, the whole system relies on the original ignition to relay through the electrical leads to the ignition charge.

Components of parachute ejection system

deployment system diagram
A diagram depicting an example of a non-electronic parachute deployment system. From: http://www.nakka-rocketry.net/parasys.html

This method, rather than rely on any sort of data, relies on the pre-computed estimates of apogee and when it happens. The length of the tube that sends the ignition charge can only be adjusted in steps of about two seconds. Those two seconds could end up being the difference between late deployment or early deployment, and on-time deployment. In addition to the large source of error introduced by the lack of precision of the apogee-predicting parachute fuse, it can be difficult to pre-calculate the timing of apogee. Without relying on any real-time rocket data, this non-electronic method of parachute deployment is can be unreliable. Accurate digital detection of apogee, is therefore key to an electronic method of parachute deployment.

Questions & Answers

Is there any normative that regulates the use of silver nanoparticles?
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biomolecules are e building blocks of every organics and inorganic materials.
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research.net
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Introduction about quantum dots in nanotechnology
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nano basically means 10^(-9). nanometer is a unit to measure length.
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characteristics of micro business
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there is no specific books for beginners but there is book called principle of nanotechnology
NANO
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Devang Reply
are you nano engineer ?
s.
fullerene is a bucky ball aka Carbon 60 molecule. It was name by the architect Fuller. He design the geodesic dome. it resembles a soccer ball.
Tarell
what is the actual application of fullerenes nowadays?
Damian
That is a great question Damian. best way to answer that question is to Google it. there are hundreds of applications for buck minister fullerenes, from medical to aerospace. you can also find plenty of research papers that will give you great detail on the potential applications of fullerenes.
Tarell
what is the Synthesis, properties,and applications of carbon nano chemistry
Abhijith Reply
Mostly, they use nano carbon for electronics and for materials to be strengthened.
Virgil
is Bucky paper clear?
CYNTHIA
carbon nanotubes has various application in fuel cells membrane, current research on cancer drug,and in electronics MEMS and NEMS etc
NANO
so some one know about replacing silicon atom with phosphorous in semiconductors device?
s. Reply
Yeah, it is a pain to say the least. You basically have to heat the substarte up to around 1000 degrees celcius then pass phosphene gas over top of it, which is explosive and toxic by the way, under very low pressure.
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s.
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for screen printed electrodes ?
SUYASH
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s. Reply
of graphene you mean?
Ebrahim
or in general
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in general
s.
Graphene has a hexagonal structure
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Source:  OpenStax, Digital detection of rocket apogee. OpenStax CNX. Dec 18, 2013 Download for free at http://cnx.org/content/col11599/1.1
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