Wednesday, September 28, 2011

A guided tour through an Arduino board

A guided tour through an Arduino board. Amazing!!.

Via make.

Saturday, August 13, 2011


Today we will talk about one of the most elegant fighter planes ever built. I have a very special memory of this aircraft because it has accompanied me since when being a kid I saw the movie "Top Gun"

F-14 principal role was fleet air defence, designed as an air superiority fighter and long range interceptor it was a large high performance carrier-borne.

The F-14 was the second american variable-sweep wing fighter aircraft after F-111. This variable-sweep wings allowed F-14 low speed approaches to carriers and manouvers with the wings swept forward and high speed interception and climb with swept back wings. Variable-sweep mechanism was fully automated so controlling the aircraft was much easier and pilot could concentrate on other more important tasks.

The F-14 was two-seated aircraft in all versions as its predecessor the F-4 Phantom II. F-14 operated with a crew fo two, a pilot and a radar officer known as RIO (Radar Interceptor Officer) who was in charge of radar, intelligence and weapon systems.

F-14 SuperTomcat en el Intrepid Air and Space Museum
One of the main weapons of the F-14 was the long range AIM-54 Phoenix missile which can destroy an enemy aircraft at 100 nautical miles. This missile was initially developed to be carried by the sea-borne version of the USAF F-111 (F-111 B) which finally never enter into service and also provided its AWG-9 radar to the F-14.
AIM-54A (left) on F-14 at NAS Pax 1984
Misil AIM-54 Phoenix
 The initial target of this long range missile was the defense of carrier battle groups from soviet Tu-4 armed with KS-1 (NATO designation AS-1 "Komet") antiship missiles which later were replaced by Tu-16 "Badger" and Tu-22 "Badger" armed with K-10S (NATO designation AS-2 "Kipper"), Kh-20 (NATO designation AS-3 Kangaroo) and Kh-22 (NATO designation AS-4 Kitchen) antiship missiles. The two later missiles were typically armed with a nuclear warhead.

Kh-22 under a Tu-22M2

AWG-9 radar could track up to 24 airborne targets, display 18 of them on the cockpit displays, and fire AIM-54 Phoenix missiles against 6 of them at the same time.The accuracy of this weapon systems was estimated on the 80%.
AN/AWG-9 Radar (via
F-14 A suffered a lot of problems during its development initial stage mainly related with the reliability of its TF-30 jet engines as the compressor failed on high angles of attack. These engines also didn't give the F-14 the expected performance as Navy expected a 1:1 weight/thrust ratio, later version B and D were fitter with the new F110-GE-400 engines that provided more than 1:1 weight/thrust ratio and allowed take-off from carriers without using the afterburner.

F-14 Tomcat intercepting a Tu-95 "Bear".
F-14 users were U.S. Navy an Iranian Air Force. It seems a bit weird that a high performance jet as the F-14 was used by the Iranian Air Force because nowadays this country is considered as a threat to U.S. Before the Islamic Revolution in 1979, Iran under the rule of the Sha Reza Palevi was a key ally for U.S. in the Middle East. In 1974 the Sha purchased an order of 30 F-14 aircraft to the U.S. and after some months the order was increased up to 80 fighters.The F-14 pruchase decission was made after a simulated combat exercise between the F-14 and F-15 that lead to the Sha's final preference for the F-14. Only 79 aircraft from the 80 initially requested were finally purchased as the last unit was retained by U.S. due to the weapon embargo declared after the kidnapping of U.S. Emabassy in Teheran. This embargo also affected spare parts and maintenance of those aircraft so at the moment the operational status of Iranian F-14 is not clear as much of the aircraft were canibilized in order to provide spare parts.
Sidra Gulf Incidents
The F-14 has been involved in two incidents with Lybian to over the Sidra Gulf. The first one took place on August 19th 1981 when two Lybian Su-22 "Fitter" attacked with an AA-2 "Atoll" air-to-air missile two F-14's of VF-41 squadron based on USS Nimitz carrier. The missile was dodged by the F-14 after which the F-14 open fire. After launching the missile both Su-22 lead to their air base trying being both of them destroyed by a AIM-9 Sidewinder missiles launched by the F-14's. According to the U.S. Navy official briefing both Lybian pilots ejected and were safely rescued.

On January 4th 1989 another combat between F-14 and Lybian aircraft ocurred over the Gulf of Sidra. This time the Lybian aircraft were soviet made MIG-23 "Flogger". At this confrontation F-14 were cleared for firing before being fired as they felt hostigated by the MIG's. After the launch of two AIM-7 "Sparrow" radar guided missiles that couldn't track their targets the U.S. aircraft fired two more missiles another AIM-7 and one AIM-9 "Sidewinder" which finally detroyed both MIG's-

General characteristics (Via Wikipedia)
Performance (Via Wikipedia)
Armament (Via Wikipedia)
Related Posts

Monday, August 1, 2011

Apart of my Universe now in English

Today starts a new stage in Apart of my Universe blog with the translation to English of some of the most visited post of the spanish version.

I hope more people could enjoy with this new release.

Saturn V


Saturn V was designed by controversial Wenher Von Braun who started his career as a rocket engineer in Nazi Germany and lately became responsible of the fearsome V-2 development program in Peenemunde facilities, the program who started modern rocketry.

The goal of Saturn V was to carry Apollo space vehicles to the Moon and it was one of most powerful rockets ever built.

Today I want to start talking about rocket engines. Space rocket engines use two different
elements: oxidizer and fuel. Both elements compound propellant which itself is an energetic source independent from the surrounding environment. This means that the rocket engine could work in vacuum of the space without any other oxygen supply.
Hypergolic propellants are those whose components ignite on contact without any other external energetic supply, this is the case of liquid hydrogen and oxygen (a.k.a LH2 and LOX).

 Liquid fuel rocket schema

Rockets could be categorized depending on the type of fuel used:
  • Liquid fuel rockets
  • Solid fuel rockets
Solid fuel rockets are much more stables and simple than liquid fuel ones but normally their overall performance is lower and could not be shut down as reactions are self-sustaining. One example of solid fuel rockets are the space shuttle boosters (those large rockets place at both sides of the central tank).

Saturn V was a liquid fuel rocket and was composed by three stages:
  • S-IC. 
  • S-II
  • S-IV B 


The first Saturn V stage was thrusted by 5 F1 rocket engines burning liquid oxygen (LOX) and RP-1 rocket fuel. These engines were developed by Rocketdyne company back in 1955. 4 of the 5 engines were placed in the outer part of the rocket and one more in a central position. The 4 outer engines rotatedby means of a hidraulic system in order to provide stability to the rocket. Propellant and oxidizier were inyected into the combustion chamber using a turbopump. This turbopump had to resist a very wide temperature range from 816 ºC in the gas inlet to -184 ºC in the liquid oxygen tank. Building F-1 engines was a very demanding activity and new materials were needed to be developed in order to cope with the violent shaking of engine startup and the temperatures generated within the engines. The temperature could reach up to 3200 ºC in the gas outlet.

F-1 rocket engine schema (Via Wikipedia)
F-1 engine testing facility picture
This stage burned out more than 8000 l. of propellant per second during 2,30 minutes and raising the rocket up to 70 km at 1500 m/s generating a total thrust of 33,85 MN where each F-1 engine provided 6,77 MN. This stage was built by Boeing company in their New Orleans facilities.

 F-1 engine schema

Saturn V first stage schema (S-IC)

Saturn V S-II stage schema
The second stage of Saturn V was developed by North American Aviation and built in California. This stage was powered by 5 J2 engines burning liquid oxygen (LOX) and liquid hydrogen (LH2) generating a thrust of 4,4 MN. J-2 engines were also built by Rocketdyne. Second stage engines where placed in the same way as the first stage engines. The development of this stage was the most complicated and suffered from several delays.

J-2 engine schema.

In order to reduce the weight of this stage, instead of using two tanks for liquid hydrogen and oxygen a unique tank for both liquid oxygen and hydrogen was developed. This tank had two separate storage parts divided by an insulating phenolic resin honeycomb to maintain the temperature gradient between liquid hydrogen and oxygen (70º C). This improvement reduced in 3,6 tons the weight of the stage.

J.2 engine picture

Stage S-II fully loaded with fuel weighed 481 tons of which 92,4% was propellant (LOX and LH2). Second stage worked for 6 minutes raising the rocket up to 174 km.

In the following map, the location of all S-II stages could be found:


Third stage of Saturn V was developed and built by Douglas Aircraft in California, it was thrusted by one J-2 engine which used the same fuel than the previously described stage. J-2 engine of this third stage was programmed for two ignitions, the first one to enter in orbit with a duration of 165 s and the second of 335 s for translunar injection where impulsed the lunar and command module to the Moon. This stage provided a thrust of 1 MN.

Saturn V S-IV B stage

During translunar injection, third stage reached an speed near to Earth's escape velocity (11,2 km/s) impulsing Saturn V to the Moon orbit. Following translunar injection there was a 40 minute journey, after which third stage was released from payload which continued its journey to the Moon.

Saturn V S-IV stage
Final assembly of Saturn V was done within Vehicle Assembly Building in Cape Canaveral space station ( later known as Cape Kennedy ). The rocket was moved to the launch pad using Crawler Transporter which was later used for transporting the Space Shuttle.

Vehicle Assembly Building
S-IC and S-II  stages were so large that the only way to transport them was by barge. S-II stage was moved from California to Florida through Panama Canal. The third stage transport could be done by plane due to the smaller dimensions of the stage but an special Guppy transport was needed.


Saturn V was responsible for the launch of the following missions:
  • Apollo 4
  • Apollo 6
  • Apollo 8
  • Apollo 9
  • Apollo 10
  • Apollo 11
  • Apollo 12
  • Apollo13
  • Apollo 14
  • Apollo 15
  • Apollo 16
  • Apollo 17
  • Skylab 1    
between November 9th 1967 and May 14th 1973.