technees

RC aircrafts

2011-10-14T02:07:00.000-07:00

Here we are with the rc planes.one of the most important emerging technologies nowadays.the purpose is to make the user,most probably a beginner,familiar with the parameters to fabricate an efficient rc aircraft.
forces acting on an aircraft are depicted as under.

weight accounts for the weight of the engine,the payloads and fuel.as the weight changes as fuel is consumed so centre of mass of aircraft also changes so we have to adjust it as per our demands.

second comes lift which is compensating the weight.and it depends on the velocity,size and shape of the aircraft.thrust is provided by the engines to overcome the drag force.

The basic principle on which all aircrafts are working at is Lift/Drag ratio.as is patent from formula the lower the drag the higher will be the lift and consequently ull be able to achieve higher altitudes.but this doesnt work for aircrafts travelling at lower speed because less drag will add to less stability and hence will result in landing problems.on the other hand if we increase the drag the aircraft will become stable but with a side effect of reduce in maximum attainable altitude and also to some extent cause takeoff problems.
the parts of an aircraft are defined here:

FUSE LAGE

the function of fuse lage is to hold the structure together.

WINGS

Wings generate lift and control the airflow while flying. Wing design is a crucial factor in aviation: a wing is designed to reduce drag at the leading edge, generate lift by its crescent and manage airflow using the rear edge.

SLAT

Slats adjust the angle of attack of the wings, increasing lift. Slats are fitted at the leading edges of the wings, and deploying them increases the angle of attack of the wings, allowing the pilot to increase the lift generated by the wings

FLAP

Flaps adjust the camber of the wings, increasing lift. Flaps are normally fitted at the trailing edge of the wings. Extending the flaps increase the camber of the wings airfoil, thus increasing lift at lower speeds, an important feature for landing

AILERON

Ailerons increase or decrease lift asymmetrically, in order to change roll and, thus, move the aircraft left or right while flying. Ailerons are hinged sections fitted at the rear of each wing. Ailerons work asymmetrically as a pair: as the right aileron goes up, the left one comes down and viceversa, thus making the aircraft roll right or left, respectively

HORIZONTAL STABILIZER

The horizontal stabiliser helps maintain an airplane's equilibrium and stability in flight. It does so by providing a mini wing at a certain distance from the main wings (typically at the back, although it can also be positioned at the from of the aircraft). This smaller wing produces enough lift to control the pitch of the aircraft and maintain its stability. Although an aircraft without a horizontal stabiliser could, in principle, fly with wings only, controlling its pitch and airspeed would be difficult, as pitch and, subsequently, airspeed can be easily disturbed by air conditions: as soon as the aircraft pitches up, the tendency is to continue pitching up even further and decrease airspeed; and as soon as the aircraft pitches down, the tendency then is to continue pitching down even further and increase airspeed. An aircraft with a horizontal stabiliser, however, could be flown hand-offs (once correctly trimmed) without affecting its pitch and speed

ELEVATORS

Elevators increase or decrease lift on the horizontal stabiliser symmetrically in order to control the pitch motion of an airplane. Elevators are hinged surfaces fitted at the rear of the horizontal stabiliser. They work symmetrically as a pair: when the elevators are up, the aircraft ascends; when the elevators are down, the aircraft descends, and when the elevators are horizontal, the aircraft flies straight

VERTICAL STABILIZER

The vertical stabiliser prevents lateral movements of the airplane. Without a vertical stabiliser, most aircraft would lose lateral control, tend to slip, increase drag and become uncontrollable

RUDDER

The rudder controls the yaw motion of an airplane. The rudder is a hinged surface fitted to the vertical stabiliser. When the rudder is turned to the left, the aircraft turns to the left in the horizontal plane; when the rudder is turned to the right, the aircraft turns to the right. The rudder is used to turn the aircraft left or right on the ground. In the air, however, the rudder is primarily used to coordinate left and right turns (the turns themselves are done with the ailerons) or to counter adverse yaw (e.g. when crosswinds pushes the airplane sideways).

AIRFOILS

there are many types of airfoilsbut in my opinion if u r looking for an airfoil dat can provide the best lift then you should opt for M06-13-128 .according to my survey this airfoil provide maximum lift when applied at an angle of attack 12-15 and Re number 2*10^5.another better option is FX63-137.this airfoil provide maximum lift at angle of attack 15 and Re number 2*10^5.Anyhow the type of airfoil you are using depends on your requirements.

PROPELLOR

propellor is used to provide forward thrust to the aircraft to overcome the drag force.

hope that the above information will to some extent give you the basic knowledge about designing an aircraft.

source:http://www.grc.nasa.gov/WWW/k-12/airplane/forces.html

wikipedia.org

apple iphone 4s

2011-10-13T15:34:00.000-07:00

so the new iphone is here;featuring the siri voice recognition system,icloud capability,an 8 mp cam(shoots video at 1080 p) and sprint availibility...it pretty much looks like an iphone 4...the device starts at $ 199 and will be available for preorder on Oct 7 and in stores on Oct 14.

the device features:

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Cellular and Wireless	World phone UMTS/HSDPA/HSUPA (850, 900, 1900, 2100 MHz); GSM/EDGE (850, 900, 1800, 1900 MHz) CDMA EV-DO Rev. A (800, 1900 MHz)⁴ 802.11b/g/n Wi-Fi (802.11n 2.4GHz only) Bluetooth 4.0 wireless technology
Location	Assisted GPS Digital compass Wi-Fi Cellular
Display	Retina display 3.5-inch (diagonal) widescreen Multi-Touch display 960-by-640-pixel resolution at 326 ppi 800:1 contrast ratio (typical) 500 cd/m2 max brightness (typical) Fingerprint-resistant oleophobic coating on front and back Support for display of multiple languages and characters simultaneously
Camera, Photos, and Video	8-megapixel camera Autofocus Tap to focus Face detection in still images LED flash Video recording, HD (1080p) up to 30 frames per second with audio Video stabilization Front camera with VGA-quality photos and video at up to 30 frames per second Photo and video geotagging
External Buttons and Connectors	External Buttons and Controls Connectors and Input/Output
Power and Battery⁵	Built-in rechargeable lithium-ion battery Charging via USB to computer system or power adapter Talk time: Up to 8 hours on 3G, up to 14 hours on 2G (GSM) Standby time: Up to 200 hours Internet use: Up to 6 hours on 3G, up to 9 hours on Wi-Fi Video playback: Up to 10 hours Audio playback: Up to 40 hours
Audio Playback	Frequency response: 20Hz to 20,000Hz Audio formats supported: AAC (8 to 320 Kbps), Protected AAC (from iTunes Store), HE-AAC, MP3 (8 to 320 Kbps), MP3 VBR, Audible (formats 2, 3, 4, Audible Enhanced Audio, AAX, and AAX+), Apple Lossless, AIFF, and WAV User-configurable maximum volume limit
TV and Video	AirPlay Mirroring to Apple TV support at 720p Video mirroring and video out support: Up to 1080p with Apple Digital AV Adapter or Apple VGA Adapter (adapters sold separately) Video out support at 576p and 480p with Apple Component AV Cable; 576i and 480i with Apple Composite AV Cable (cables sold separately) Video formats supported: H.264 video up to 1080p, 30 frames per second, High Profile level 4.1 with AAC-LC audio up to 160 Kbps, 48kHz, stereo audio in .m4v, .mp4, and .mov file formats; MPEG-4 video up to 2.5 Mbps, 640 by 480 pixels, 30 frames per second, Simple Profile with AAC-LC audio up to 160 Kbps per channel, 48kHz, stereo audio in .m4v, .mp4, and .mov file formats; Motion JPEG (M-JPEG) up to 35 Mbps, 1280 by 720 pixels, 30 frames per second, audio in ulaw, PCM stereo audio in .avi file format
Headphones	Apple Earphones with Remote and Mic Frequency response: 20Hz to 20,000Hz Impedance: 32 ohms
Mail Attachment Support	Viewable Document Types .jpg, .tiff, .gif (images); .doc and .docx (Microsoft Word); .htm and .html (web pages); .key (Keynote); .numbers (Numbers); .pages (Pages); .pdf (Preview and Adobe Acrobat); .ppt and .pptx (Microsoft PowerPoint); .txt (text); .rtf (rich text format); .vcf (contact information); .xls and .xlsx (Microsoft Excel)
Sensors	Three-axis gyro Accelerometer Proximity sensor Ambient light sensor
System Requirements	Mac System Requirements Mac computer with USB 2.0 port OS X v10.5.8 or later iTunes 10.5 or later (free download from www.itunes.com/download) Apple ID (required for some features) Internet access PC System Requirements PC with USB 2.0 port Windows 7; Windows Vista; or Windows XP Home or Professional with Service Pack 3 or later iTunes 10.5 or later (free download from www.itunes.com/download) Apple ID (required for some features) Internet access
Environmental Requirements	Operating temperature: 32° to 95° F (0° to 35° C) Nonoperating temperature: -4° to 113° F (-20° to 45° C) Relative humidity: 5% to 95% noncondensing Maximum operating altitude: 10,000 feet (3000 m)
Languages	Language Support English (U.S.), English (UK), Chinese (Simplified), Chinese (Traditional), French, German, Italian, Japanese, Korean, Spanish, Arabic, Catalan, Croatian, Czech, Danish, Dutch, Finnish, Greek, Hebrew, Hungarian, Indonesian, Malay, Norwegian, Polish, Portuguese, Portuguese (Brazil), Romanian, Russian, Slovak, Swedish, Thai, Turkish, Ukrainian, Vietnamese Keyboard Support English (U.S.), English (UK), Chinese - Simplified (Handwriting, Pinyin, Wubihua), Chinese - Traditional (Handwriting, Pinyin, Zhuyin, Cangjie, Wubihua), French, French (Canadian), French (Switzerland), German (Germany), German (Switzerland), Italian, Japanese (Romaji, Kana), Korean, Spanish, Arabic, Bulgarian, Catalan, Cherokee, Croatian, Czech, Danish, Dutch, Emoji, Estonian, Finnish, Flemish, Greek, Hawaiian, Hebrew, Hindi, Hungarian, Icelandic, Indonesian, Latvian, Lithuanian, Macedonian, Malay, Norwegian, Polish, Portuguese, Portuguese (Brazil), Romanian, Russian, Serbian (Cyrillic/Latin), Slovak, Swedish, Thai, Tibetan, Turkish, Ukrainian, Vietnamese Dictionary Support (enables predictive text and autocorrect) English (U.S.), English (UK), Chinese (Simplified), Chinese (Traditional), French, French (Canadian), French (Switzerland), German, Italian, Japanese (Romaji, Kana), Korean, Spanish, Arabic, Catalan, Cherokee, Croatian, Czech, Danish, Dutch, Estonian, Finnish, Flemish, Greek, Hawaiian, Hebrew, Hindi, Hungarian, Indonesian, Latvian, Lithuanian, Malay, Norwegian, Polish, Portuguese, Portuguese (Brazil), Romanian, Russian, Slovak, Swedish, Thai, Turkish, Ukrainian, Vietnamese Siri Languages English (U.S., UK, and Australian), French, German
In the Box	iPhone 4S Apple Earphones with Remote and Mic Dock Connector to USB Cable USB Power Adapter Documentation

source:http://store.apple.com/us/browse/home/shop_iphone/family/iphone/iphone4s

technees

RC aircrafts

apple iphone 4s

Cellular and Wireless

Location

Display

Camera, Photos, and Video

External Buttons and Connectors

Power and Battery5

Audio Playback

TV and Video

Headphones

Mail Attachment Support

Viewable Document Types

Sensors

System Requirements

Mac System Requirements

PC System Requirements

Environmental Requirements

Languages

Language Support

Keyboard Support

Dictionary Support (enables predictive text and autocorrect)

Siri Languages

In the Box

Power and Battery⁵