The H225M (previously known as EC 725) medium-sized (11t), twin-engine helicopter is a member of the Cougar helicopter family developed by Eurocopter. The helicopter has been developed in the military H225M version and in a civil EC 225 version.
The helicopter completed its first flight in November 2000 and is now in service in ten countries worldwide. The French Air Force, the launch customer, ordered six H225Ms for use in a combat search-and-rescue (CSAR) role. The first was delivered in February 2005 and deliveries concluded in May 2007. The French Special Operations Command ordered eight H225M helicopters in November 2002.
French H225M helicopters were deployed in 2006 in Lebanon to aid evacuation of personnel, as well as in Afghanistan. Two helicopters have been stationed in Kabul since the beginning of 2007, in support of the Nato International Security Force. The H225M is used for more than 95% of operations in Kabul.
Orders and deliveries of Eurocopter’s helicopter
In April 2009, an additional five H225M helicopters were ordered by the French Defence Ministry as part of the government’s €220m ($314m) economic recovery plan. The first of five H225M helicopters was delivered in June 2011. The remaining four are scheduled for delivery in 2012.
Two H225M helicopters have also been ordered by Dirgantara for the Indonesian Air Force. In April 2012, Eurocopter received an order from PT Dirgantara Indonesia / Indonesian Aerospace to supply six additional helicopters for the Indonesian Air Force. The delivery of first helicopter was concluded in November 2014.
In September 2008, Malaysia announced the selection of the H225M for an initial order of 12 helicopters. However, the contract award has been indefinitely delayed due to budgetary constraints. Eurocopter signed a cooperation contract with the Malaysian Ministry of Defence at the 49th Paris air show in June 2011, related to the supply of the 12 H225M helicopters to the Royal Malaysian Air Force (RMAF) for search and rescue (SAR) operations.
These new aircraft replaced the existing fleet of Sikorsky S-61 Sea King rotorcraft. The first two helicopters were delivered in December 2012 and the remaining were delivered between 2013 and 2014.
In December 2008, Brazil placed a €1.9bn ($2.72bn) order for 50 H225M helicopters; 16 for the navy, 16 for the army and 18 for the air force. The helicopters are being manufactured in Brazil by Eurocopter’s subsidiary Helibras. The first three H225M helicopters were delivered to Brazil in December 2010. The first indigenously-built H225M helicopter was delivered to Brazilian Navy in June 2014. Deliveries are scheduled for completion by 2016.
Brazilian Navy H225M in naval combat version
- Helibras presents the first H225M in naval combat version, developed for the Brazilian Navy
- Advanced anti-surface warfare and tactical capabilities open new mission capabilities for the multirole H225M utility helicopter.
- Flight-test will pave the way for military certification in 2018.
Helibras and Airbus Helicopters have opened a new chapter in the history of the H225M multirole utility helicopter with the official presentation of the first aircraft in naval combat configuration. Developed and assembled locally by Helibras, Airbus Helicopters’ subsidiary in Brazil, this new H225M version is designed to meet the demanding requirements of the Brazilian Navy, with mission capabilities including anti-surface warfare and maritime surveillance.
This evolution of the H225M is built around a Helibras-developed tactical mission system including an APS-143 surveillance radar, advanced self-protection systems as well as signals intelligence capabilities. The helicopter is also equipped with two AM39 Exocet anti-ship missiles, while the cargo bay accommodates a dedicated sensor operator console providing the mission commander with an overview of the tactical situation. An automatic identification system (AIS) will also allow crew members to gather information on surface vessels.
“I am particularly proud to present this new version”, said Helibras president Richard Marelli. “This latest and unique version of the H225M is a testimony of the hard work our teams have been doing here in Brazil in close collaboration with Brazilian military customers. It also demonstrates our ability to effectively transfer technology, skills and know-how to Brazil, and our commitment to support the development of the country’s aerospace industry”.
The helicopter unveiled this week in Itajubá will be the first H225M in naval combat version to be delivered to the Brazilian Navy in 2018, after the end of military certification trials. It is part of a global order for 50 H225Ms for the Brazilian armed forces, 26 of which have already been delivered to the Brazilian Air Force, Navy and Army. Helibras is in charge of the complete assembly of H225Ms in Itajubá, including integration of mission equipment, flight line activities and industrial acceptance. With a target to achieve 50% of national content by 2020, Helibras has developed a local supply chain which includes more than 37 Brazilian companies. Source airbushelicopters.com
In March 2010, the Mexican Air Force ordered six H225M helicopters from Eurocopter. These helicopters will be used for transport and civil security missions. Another six H225M rotorcraft were ordered by the Mexican Air Force in September 2010, increasing the total number of aircraft orders to 12. The Mexican Navy ordered nine H225M helicopters to carry out CSAR, medical evacuation (MEDEVAC) and troop transport missions.
In July 2009, the H225M was presented on the static display at the Royal International Air Tattoo, at RAF Fairford. In September 2009, it was displayed at Defence Systems & Equipment International event, held in London.
The new H225M is based on the proven fuselage and structural design of the Cougar mk2, with a new five-bladed main rotor and reinforced main gearbox. The helicopter also has a new integrated display suite and piloting system. The new H225M version is able to carry a much higher military payload at a faster speed, while it also has an increased range.
In May 2012, Eurocopter received a letter of intent (LoI) from the Republic of Kazakhstan to deliver 20 H225M helicopters.
In September 2012, the Royal Thai Air Force ordered four H225M search and rescue helicopters. Deliveries were concluded in August 2015. Two more helicopters were ordered in 2014 for delivery in 2016.
Capabilities of the H225M Cougar
The aircraft is suitable for a wide range of missions such as tactical troop transport, special operations, SAR, CSAR, maritime surveillance, humanitarian support logistic ground support, medical evacuation and shipborne operations. The ferry flight range is more than 1,200nm.
In the tactical troop transport role, the helicopter can carry 19 troops over a 250nm radius of action. In the CSAR role, the H225M is able to rescue a downed crew at a radius of action of 280nm.
Design features of the twin-engine helicopter
The fuselage is of light alloy material with a large composite intermediate structure and cowlings. The machine-milled frames are strengthened for crashworthiness. The crew and troops are protected by removable armour plating. The maximum seat capacity is two crew and 29 troops.
The helicopter is fitted with a dual hoist system and has a sling capacity of 5t.
The helicopter is equipped with new ‘Spheriflex’ main and tail rotorheads. The diameter of the main rotor system is 16.2m. The five-bladed main rotor is fully composite, with a composite spar, multiple box structure and anhedral tipcaps. The five-blade arrangement provides a very low level of vibration. The rotors and horizontal stabiliser can be equipped with an anti-icing and de-icing system.
Helicopter cockpit and weapon systems
The H225M is equipped with an all-glass cockpit, with new avionics and a new integrated display system, including a digital map.
The display suite includes seven active matrix liquid crystal displays: four multifunction 6in x 8in displays and two 4in x 5in helicopter parameter displays.
The advanced helicopter cockpit and avionics system (AHCAS) includes an automatic flight control system developed by SAGEM, integrating the flight, navigation and tactical mission data.
The helicopter is equipped with radar and FLIR (forward-looking infrared) for day and night-time SAR capabilities. The navigation suite includes Doppler radar, global positioning system and inertial navigation system.
Euroflir™ 350: Long-range electro-optical system
The Euroflir™ 350 provides long-range observation and targeting capabilities enabling unsurpassed image quality thanks to advanced local image processing within a compact and lightweight system.
The combat-proven Euroflir™ 350 is already used on many French Army and other nations’s rotary-wings (H125M Fennec, AS350 Ecureuil, AS532 Cougar, H225M Caracal, etc.) deployed in today’s most demanding theaters. Source: safran-electronics-defense.com
Brazilian Air Force H225 operate Star SAFIRE III
Star SAFIRE III Features
- Multi-mission capable
- High-resolution color spotter scope
- Matched multi-FOV optics
- Image intensified low-light camera
- Image blending
- Reliable 24/7 operation
- Optimized usability
- Multiple laser payloads
- Maintain Star SAFIRE family compatibility
- Commercially developed, MIL qualified
- Can be used in applications as diverse as land force protection, shipboard open ocean and littoral patrol, and long range airborne reconnaissance
- Extends identification range performance by providing maximum detail from covert stand-off distances
- All cameras feature multiple FOVs maintaining situational awareness while also achieving long range performance and enabling Image Blending
- Brings true all day and all night imaging capability in multiple wavebands, and forms the basis for image blending
- Combine critical spectral information from IR imager with image intensified low-light camera or long range spotter scope
- High MTBF and proven combat survivability in demanding arctic and desert environments
- View and track ground locations using the fully-embedded IMU; follow moving targets with the multi-mode Autotracker
- Covertly illuminate wide areas, point out distant targets to other forces, and determine target distance and location
- Total cable compatibility allows operators to upgrade existing Star SAFIRE family installations with plug-and-play simplicity
- All-weather design is qualified to the most demanding requirements of MIL-STD-810 and 461
Star SAFIRE III Source flir.com
Sigma 95N Inertial Navigation System
Sigma 95N is a high-performance navigation system designed for most demanding aeronautic applications that require high navigation and guidance accuracy.
The Sigma 95N INS is based upon three highly accurate digital laser gyroscopes. It is equipped with a GPS or GPS/Glonass receiver and makes use of a powerful multimode Kalman filter to optimize performance by hybridizing inertial and satellite data. It can also integrate NATO’s new Selective Availability/Anti-Spoofing Module (SAASM) and in the close future, the Europe’s upcoming Gallileo system. Its open design and versatile interfaces (Mil-Std-1553B, Arinc, Gost, etc.) allow easy integration in all types of avionic configurations and platforms.
The SAR system can be programmed to provide automatic search patterns, transition and hover.
The helicopter can carry side-firing armaments, such as two 7.62mm general purpose machine guns and a 20mm cannon. The helicopter can also be fitted with axial pods, such as two 68mm rocket launchers or two 20mm cannons.
7.62 mm FN MAG machine gun
|Operating principle||Gas operated, open breech|
|Overall length||1260mm (49.6″)|
|Weapon width||118.7mm (4.67″)|
|Weapon width with bipod extended||408mm (16.1″)|
|Weapon width with bipod folded||160mm (6.3″)|
|Weapon height||263mm (10.35″)|
|Weapon height with bipod extended||318mm (12.5″)|
|Weapon height with bipod folded||225mm (8.86″)|
|Weapon weight||11,8 kg (26.01 lb)|
|Barrel weight||3.05 kg (6.75 lb)|
|Barrel length||630mm (24.80″)|
|Cyclic rate of fire||650 to 1,000 RPM|
|Firing mode||Full auto|
|Role||General Purpose Machine Gun|
Dillon Aero M134D
The Dillon M134D Gatling Gun is the finest small caliber, defense suppression weapon available. It is a six barreled, electrically driven machine gun chambered in 7.62mm NATO and fires at a fixed rate of 3,000 shots per minute. Gatling Guns typically feed from a 3,000 or 4,000 round magazine. They are capable of long periods of continuous fire without threat or damage to the weapon making them an excellent choice for defensive suppression.
Dillon Guns are reliable. The M134D has system life in excess of 1,500,000 rounds and an average time between stoppage greater than 30,000 rounds. In the unlikely event of a stoppage the weapon can be serviced and made operational again in under one minute. The multi barrel design means that each barrel only experiences a 500 round per minute rate of fire. This allows for repeated long bursts of fire and a barrel group life of 200,000 rounds. Source: dillonaero.com
|Magazine||Belt fed, 4.000 rounds|
|Operation||Gatling principle, externally powered|
|Rate of fire||3.000 rpm|
|Barrel length||559 mm|
|Muzzle velocity||869 m/s|
|Sights||Various optional optical sights|
Two 70mm rocket launchers or two 20mm cannons
NC 621 cannon pod
The NC 621 cannon pod extends the range of missions (attack, close fire support, protection, self-defence) of the helicopters and lightest aircrafts. It provides airplanes with 20mm firepower previously restricted to 0.50 weapons. The NC 621 has been developed around the 20 M 621 cannon which is well known for its high accuracy, for simplicity (operation and maintenance) and which fires the 20mm x 102 NATO standard ammunition. The effectiveness and reliability of the NC 621 has been widely proven on various platforms.
– Gaz operated,
– Average firing rate: 750 rounds per minute,
– Ammunition stowage capacity: 180 or 250 ammunition
– Effective range: up to 2,000m
70 mm rocket system FZ225
FZ225 is a lightweight composite material high-drag, straight cylindrical 19-tube reusable launcher designed for helicopter use. The FZ225 is equipped with removable universal dual purpose FZ125 detent mechanism enabling to fire FFAR and WA rockets.
It can be fitted with an optional removable rear fairing.
The FZ225 rocket launcher system includes a nineteen (19) tube rocket composite central section with equipped with a Launcher Interface Unit (LIU).
- Outer diameter : 402 mm
- Overall length : 1668 mm
- Total mass (empty) : 45 kg
- 14” NATO standard suspension lugs
FZ275 LGR : Semi-Active Laser (SAL) Guided Rocket
The FZ275 LGR guided rocket closes the gap between the long-range high-value missiles and the shorter range guns/cannon and unguided rockets, thus affording a full range of precision effects from a platform to defeat soft and light armoured targets.
This rocket complies with the armies’ requirement for precise and reliable ammunitions capable of reducing exposure to danger and avoiding collateral damage which nowadays causes injuries to civilians.
- Calibre : 2.75” (70mm)
- Nominal length : ~1800mm
- All up round weight : 12.5 kg (before burn)/9.1 kg (after burn)
- Guidance : SAL (Semi-Active Laser)
- Steering type : 4 folding canards
- Laser : compatible with STANAG 3733 or used defined code
- Range : 1500m up to 6000m
- CEP<1m (at 6km range)
The SAL-Laser Guided Rocket FZ275 LGR requires designation of the target by a laser designator.
The rocket has an in-built laser seeker that can read a specially coded laser being reflected off a target. This target can be marked either before launching the rocket (LOBL), after launch (LOAL) or even by a remote source, such as a soldier on the ground or another second flying platform. This versatility provides the helicopter with a far greater survivability and the ability to attack without moving into a target’s vision.
FZ has developed 2 different configurations for its laser guided rocket :
- stand alone : easy and quick implementation of laser guided rocket FZ275LGR on platforms with FZ rocket system requiring any major modification
- integrated : full integration with full functionality increasing the capability envelope of FZ275LGR guided rocket :
The helicopter’s electronic warfare systems include a radar warning receiver, laser warning receiver, missile approach warner and chaff and flare dispensers.
System IDAS / CIDAS SAAB (Brazilian Air Force)
The Integrated Defensive Aids Suite (IDAS) or S uite Auxiliary Equipment Integrated Defense Swedish of SAAB , is responsible for peripheral self-protection H-225M and aims to increase their ability to survive in modern conflict scenarios, consisting of sensors working alerting with advance to the crews of radar, laser emission and hostile missile threats.
MAW-300 (Missile Aproach Warning)
The missile approach, works the UV spectrum (Ultra Violet), through special filters with capacity to “capture” photons (wavelength) at long distance. Using what the manufacturer calls the “neural classifier network,” it works with the positioning of the platform in space with respect to its in-flight displacement, using the aircraft’s native INS / GPS data, allows, once a threat is detected , its discard when it is a false alarm, or when valid, it classifies its degree of risk, projecting, by probability, the future trajectory of the missile, being able to trigger defensive measures with Flare / Chaff directing to the threat. Each sensor that has a field of action in 110º, has its own processor, uses digital signal with hierarchical architecture of data processing, to optimize information in real time. The data of each sensor, which can detect and process multiple potential targets, is transferred to a digital control unit (MAW controller) in the Electronic Warfare Controller (EWC). Four sensors are used in each quadrant of the helicopter, providing 360º coverage, two front and one above the pilot / co-pilot window and two behind, at the end of the main landing gear fairing in a triple conjugate station with two more sensors ( LWS-310 / RWS-300).
LWS-310 (Laser Warning System)
System laser Alert , is operable using four sensors connected to EWC (Electronic Warfare Controller), hardware responsible for processing data obtained by sensors. The LWS-310 sensor is an arc-shaped cube containing eight multidirectional mini-windows with a large angular aperture and capable of reading 0.5-1.7 μm (microns) wavelength , with high sensitivity to various lasers. It can classify threats as laser rangefinders , designators and lasers used for missile guidance with an embedded system that has data library. Like the MAW-300, the LWS-310 is installed in the quadrants of the H-225M, being in the back in the triple station, in the front is in dual station conjugated with the RWS-300 sensor on the sides near the junction of the radar dome.
RWS-300 (Radar Warning System)
System Radar Warning is composed of the RWS-300 sensor, it is the antenna (SAM Spiral Antenna Module) card , an antenna spiral shape covered by a cylindrical hood, is capable of approved varying electro-magnetic emissions simultaneously with set range between 0.7-40 GHz (pulse radar) and 0.7-18 GHz (counter measures) frequency. It has the same operating principle of the MAW system using the EWC (Electronic Warfare Controller) can trigger the defensive systems of the helicopter in case of detection of threats.
BOP-L (Countermeasures-dispensing function)
Dispensador Counter-measures , shaped device shelter (box) that is installed on each side of the helicopter tail cone. In an internal drawer is the pyrotechnic ejection loads of CHAFF and FLARE, electronically driven. CHAFF has the function of trying to confuse the firing radar system that makes up the ground anti-aircraft batteries or guidewires that are embedded in the missiles that are engaging the helicopter. When a critical radar threat is detected (missile coming in), shelter charges that blow up in the air are ejected, releasing up to thousands of ultra thin blades forming a cloud, made up of metals or special material with properties to better reflect radar waves, can to simulate fake targets for an acquisition system, with a great chance of diverting the radar-guided missile into the aircraft. FLARE is intended to attract and divert missiles with heat guidance (IR). Composed of white phosphorus (WP) material, when ejected from its capsule and due to its chemical properties, it is in high combustion in contact with oxygen, producing intense heat, the heat produced can confuse the IR missile seeker in pursuit by diverting it, in evasive maneuver, several charges are launched simultaneously to increase the chances of success. The BOP-L can be easily replenished by changing the drawer, has a low weight, can be pre-programmed in the sequence, BIT (check ground), and can carry up to 32 loads. Source portaldefesa.com
HForce GWC modular weapons system
Option 0 – the helicopter is provisioned for the HForce GWC for later retrofit, but not yet equipped with it.
Option 1 – Ballistic firing with HMSD. This includes pilot HMSD, plus the integration of a combination of 12.7 mm HMPs, 20 mm cannons, and unguided rockets.
Option 2 – Ballistic firing with HMSD and electro-optical/infrared (EO/IR) targeting. This includes Option 1, plus pilot and co-pilot/gunner HMSD, and EO/IR targeting.
Option 3 – Ballistic firing with HMSD and EO/IR and guided weapons. This includes Option 2, plus air-to-surface and air-to-air missiles, and laser-guided rockets.
Thales Scorpion Helmet Mounted Cueing Systems (HMCS)
Thales to supply Scorpion® helmet display
- This is the first helmet mounted display that features colour symbology and video imaging for both daytime and nighttime missions.
- Thales will be responsible for the viability study, testing phase, integration with test aircraft, qualification support and integration in the fleet.
Thales will also be responsible for the development and production of the specific configuration for the Spanish Air Force EF-18. The system is already operational in multiple platforms in the United States
Scorpion® is a ‘force multiplier’ system offering full colour symbology (navigation, intelligence, combat, etc.) for both nighttime and daytime missions, in addition to target cueing in potentially degraded visual environments, therefore easily allowing target designation and allocation of points of interest with the aircraft’s sensors. Scorpion® is fully interchangeable between helmets/pilots as it is installed directly over standard helmets, allowing the total amount of equipment necessary for the fleet to be reduced, thus favouring maintenance and reducing life-cycle costs.
Thales will be responsible for the viability study, testing phase, integration with test aircraft, qualification support and integration in the fleet. Thales will also be responsible for the development and production of the specific Scorpion® configuration for the Spanish EF-18 including ejection safety analysis. The qualification phase includes inter-operability with the IRIS-T missile and the daytime/ nighttime-imaging pod for cueing lightening targets.
Note to editors
The HMCS uses the patented and innovative HObIT (Hybrid Optical based Inertial Tracking) technology, the hybrid reference system that warrants high precision with minimum cabin intrusion. For nighttime missions, Scorpion can be operated with standard unmodified night vision goggles (NVG), therefore offering the same quality colour/video imaging symbol combination.
The system is already operational on multiple platforms in the United States such as the F16 Block 30/32 and the A10 ‘Thunderbolt II’ and has been flight tested on the F-22, the NH-90 and many other platforms. At present, the system is being actively evaluated by other clients globally. Source thalesgroup.com
Turbomeca Makila 2A turboshaft engines
The helicopter is powered by two Turbomeca Makila 2A turboshaft engines, each providing 1,800kW of power, an increase of 14% over the previous 1A2 engine version.
Each engine, complete with systems and accessories, is independent. An infrared suppression system is installed to reduce the thermal signature of the helicopter.
The engines are equipped with dual-channel full authority digital engine control (FADEC), while protective air intake grids prevent ingestion of debris into the engines. The free turbine features blade shedding architecture for high reliability and safety.
2 × Turboméca Makila 2A1 turboshaft engine
Launched at the end of the 90s, the Makila 2A features a new, higher-performing compressor module as well as dual-channel Full Authority Digital Engine Control (FADEC). The Makila 2A powers the EC225 and H225M Caracal helicopters manufactured by Airbus Helicopters.
The Makila 2A is fourteen per cent more powerful than the 1A. It delivers a take-off power of 2,101 shp and a cruising power of 1,970 shp. Maximum power using the One Engine Inoperative (OEI) rating is 2,415 shp. Time Between Overhaul (TBO) is 3,500 hours. It was certified in 2004.
In 2014, Safran Helicopter Engines launched the Makila 2B, a revision of the 2A, intended for the H225 helicopter manufactured by Airbus Helicopters. The 2B has a new combustion chamber and new high-pressure turbine blades for increased take-off performance and, in particular, payload. The Makila 2B underwent initial flight testing in 2014 and progress in ongoing. Source safran-helicopter-engines.com
ART2 units are installed on EC 225 and EC 725 Caracal helicopters.
- MTR390 control unit:
- for the turbine engine of the same name produced by the MTR consortium (MTU, Turbomeca, Rolls Royce),
- modular control unit,
- embedded system that monitors the craft’s operation status.
The main fuel tanks, with a capacity of 2,539l, are installed beneath the floor of the cabin. Auxiliary tanks can be installed in the cargo hook well (capacity of 324l) or at the rear of the cabin (990l). The helicopter can be equipped with a probe for air-to-air refuelling. The refuelling system has already been validated on the Cougar mk2.
Saphir 20 APU
The Saphir 20 Auxiliary Power Unit has been designed to meet the on-board power requirements of the Super Puma multi-role helicopter.
With its excellent compactness-weight-power ratio, the Saphir 20 makes the aircraft totally self-sufficient for starting and ground operation through the supply of 30 kVA of electrical power.
It powers several systems through the helicopter’s batteries in complete safety.
ts reliability allows it to operate in severe conditions.
The electrical power delivered by the Saphir 20 can supply the following ground functions:
- Air conditioning including cockpit heating
- Power generation for:
- starting the main engines
- supplying equipment (standby, verification and maintenance phases)
- Back-up electricity generation
- Hydraulic power for flight controls
Main gearbox and landing gear of Eurocopter’s H225M Cougar
The H225M main gearbox is reinforced for compatibility with the increased turbine engine power and the increase in the helicopter’s maximum weight. The helicopter uses the gear train identical to that of the Cougar mk2. An emergency lubrication spray is installed in the gearbox to allow a 30-minute flight with no oil.
The helicopter has retractable crashworthy tricycle-type landing gear supplied by Messier-Bugatti. Each unit retracts rearward and is fitted with dual chamber oleo pneumatic shock absorbers. Emergency floatation units can be installed on the main landing gear fairings and on the forward section of the fuselage.
Performance of the Cougar-family helicopter
The H225M can climb at the rate of 3.6m/s. The maximum and cruise speeds of the aircraft are 324km/h and 277km/h respectively. The range is 1,482km and service ceiling is 6,095m.
|long-range tactical transport helicopter|
|Brazil, France, Indonesia, saudi Arabia, malaysia, Mexico|
|1 or 2 pilot|
|2 × Turbomeca Makila 2A1 turboshafts, 1,776 kW (2,382 shp) each|
|Maximum speed: 262 km/h|
|1,339 km maximum|
|5,330 kg empty|
|Advanced helicopter cockpit and avionics system (AHCAS), radar and FLIR (forward-looking infrared) for day and night-time search and rescue capability, Doppler radar, global positioning system and inertial navigation system.|
|Length: 19.50 m; Rotor Diameter: 16.2 m;
Height: 4.6 m
Technical data airrecognition.com
Main material source airforce-technology.com
Images are from public domain unless otherwise stated
Revised Nov 26, 2017
Updated Feb 16, 2020