Salam 1 malaysia,
Selamat kembali semula ke sekolah bagi pelajar2 n guru2. Saya percaya bulan jun dan julai merupakan bulan yang sibuk bagi peminat2/peserta2 pertandingan roket air dan juga guru pembimbing. Kebiasaannya pertandingan roket air akan di adakan pada bulan jun/julai bagi peringkat daerah/negeri.
Daerah segamat akan mengelolakan pertandingan roket air semasa FST pada awal bulan julai nanti (7 dan 8 julai 2010- rabu/khamis). Diharapkan kepadan semua peserta dapat bersedia daripada sekarang.
Tahniah saya ucapkan kepada 2 org peserta sekolah maokil( hanafizi dan wan md nizam-pelajar ting 2) yang bertungkus lumus berlatih sepanjang cuti persekolahan yang lepas dan keputusannya amat membanggakan. Mereka telah dapat menghasilkan satu model roket air versi terbaru iaitu V7 (gambar roket akan di muatnaik selepas FST berlangsung....takut bocor rahsia...hahahahaha...) yang menepati sasaran 100 m, Daripada 10 kali pelancaran hanya beberapa kali sahaja roket air tersebut terkeluar daripada bulatan sasaran.
Syabas saya ucapakan. Semoga tahun ini kita masih lagi dapat mewakili daerah segamat ke pertandingan negeri pada pertengahan bulan julai nanti......insyallah.....
Ahad, 20 Jun 2010
Ahad, 13 Jun 2010
Sabtu, 12 Jun 2010
Jumaat, 4 Jun 2010
Mekanisma utk mengeluarkan payung terjun/paracut : Bendera peka kelajuan-
Saya telah kemukakan satu tajuk dalam blog ini berkaitan dengan penggunaan jangka spring iaitu cara untuk mengeluarkan payung terjun/paracut pada bahagian puncak ketinggian semasa pelancaran. Selain daripada cara di atas ada satu cara lagi yang boleh di cuba oleh peminat2 roket air iaitu melalui bendera peka/sensitif kelajuan .
Bagi mengatasi masalah kegagalan roket air mengeluarkan paracut dan kembang di udara, saya bersama pelajar sekarang sedang mencuba satu teknik/kaedah bendera sensitif/peka kelajuan. Idea bagi membolehkan paracut kembang di udara ini juga diperolehi daripada pembacaan saya dari laman web yang berkaitan dengan roket h2o.
Untuk mengetahui:
Bagaimana bendera sensitive kelajuan berfungsi?
Bagaimana langkah2 yang perlu dilakukan untuk menghasilkan bendera sensitif/peka kelajuan?
Sila berkunjung ke laman blog ini sedikit masa lagi.....
terima kasih....
Bagi mengatasi masalah kegagalan roket air mengeluarkan paracut dan kembang di udara, saya bersama pelajar sekarang sedang mencuba satu teknik/kaedah bendera sensitif/peka kelajuan. Idea bagi membolehkan paracut kembang di udara ini juga diperolehi daripada pembacaan saya dari laman web yang berkaitan dengan roket h2o.
Untuk mengetahui:
Bagaimana bendera sensitive kelajuan berfungsi?
Bagaimana langkah2 yang perlu dilakukan untuk menghasilkan bendera sensitif/peka kelajuan?
Sila berkunjung ke laman blog ini sedikit masa lagi.....
terima kasih....
Khamis, 3 Jun 2010
Nose Cones
Nose cones, along with fins, are one of the most critical aerodynamic components of a rocket. A simple paper cone taped on top of the rocket is enough to significantly reduce the rocket's coefficient of friction, however more complex shapes may be used to further improve a rocket's performance (and some are surprisingly easy to make). There are three common shapes used for nose cones: conical, ogive and parabolic, as shown in the diagram below.
A common misconception is that the most aerodynamis is the conical shaped nose cone. This probably comes from the fact that frequently space-going vehicles have nose cones this shape (for example the space shuttle's solid rocket boosters). However this shape is only suitable for supersonic flights (above the speed of sound). For water rockets, which only achieve a speed of about 1/4 to 1/3 the speed of sound, a parabolic shape turns out to be the most efficient. Similarly, you often see model rockets (the pyrotechnic type) with parabolic nose cones as well. Several methods exist to construct nose cones of this shape. The simplest and quickest is to use the top of another bottle cut off and taped or glued (or attached some other way) to the top of the rocket. Another technique that is used is guppying. This involves heating the bottom of a pressurised bottle so that it expands into a rounded shape. While this method does give very good results, it takes a lot of practice to get right.
A guppied bottle (picture courtesy Clifford Heath; http://polyplex.org/cjh/rockets/)
However, to be perfectly honest, while aerodynamics are quite important in water rocketry, the difference between a conical nose cone and a parabolic nose cone is not that significant. With this in mind, you often come across people who make conical paper nose cones, for example Robert Youens' Coney design (note however that the very long cone is also an integral part of the overall design in order to make the rocket backslide).
Another common type of nose cone is one made out of foam. Using a nicely shaped end of a 'foam noodle' (those cylindrical shaped foam 'toys' used for floating in pools) can be very effective - they are lightweight, aerodynamic and allow you to use 'bounce' recovery (where the nose cone compresses and absorbs the rocket's energy upon impact). Have a look at Lonnie's page for more information on making one of these nose cones. For some theory about bounce recovery and crush zones, take a look at my crush zone theory page.
A common misconception is that the most aerodynamis is the conical shaped nose cone. This probably comes from the fact that frequently space-going vehicles have nose cones this shape (for example the space shuttle's solid rocket boosters). However this shape is only suitable for supersonic flights (above the speed of sound). For water rockets, which only achieve a speed of about 1/4 to 1/3 the speed of sound, a parabolic shape turns out to be the most efficient. Similarly, you often see model rockets (the pyrotechnic type) with parabolic nose cones as well. Several methods exist to construct nose cones of this shape. The simplest and quickest is to use the top of another bottle cut off and taped or glued (or attached some other way) to the top of the rocket. Another technique that is used is guppying. This involves heating the bottom of a pressurised bottle so that it expands into a rounded shape. While this method does give very good results, it takes a lot of practice to get right.
A guppied bottle (picture courtesy Clifford Heath; http://polyplex.org/cjh/rockets/)
However, to be perfectly honest, while aerodynamics are quite important in water rocketry, the difference between a conical nose cone and a parabolic nose cone is not that significant. With this in mind, you often come across people who make conical paper nose cones, for example Robert Youens' Coney design (note however that the very long cone is also an integral part of the overall design in order to make the rocket backslide).
Another common type of nose cone is one made out of foam. Using a nicely shaped end of a 'foam noodle' (those cylindrical shaped foam 'toys' used for floating in pools) can be very effective - they are lightweight, aerodynamic and allow you to use 'bounce' recovery (where the nose cone compresses and absorbs the rocket's energy upon impact). Have a look at Lonnie's page for more information on making one of these nose cones. For some theory about bounce recovery and crush zones, take a look at my crush zone theory page.
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