What is the Grob G 109 and who manufactured it?

The Grob G 109 is a light aircraft developed by Grob Aircraft AG, a company based in Mindelheim Mattsies, Germany. It is classified as a motor glider.

When did the Grob G 109 first fly, and what were its initial variants?

The Grob G 109 prototype first flew on March 14, 1980. The production G 109A form followed shortly after, with the G 109B variant introduced in 1984.

What is the seating configuration and visibility like in the Grob G 109?

The Grob G 109 features side-by-side seating for the pilot and a passenger or student. It offers good visibility through large windows.

What was the role of the Grob G 109 in the Royal Air Force (RAF)?

The Grob G 109, specifically the G 109B variant, was used by the Royal Air Force Volunteer Gliding Squadrons (VGS) to train air cadets in basic gliding and flying skills. It was used for gliding induction and scholarship courses.

What was the RAF's designation for the Grob 109B, and when was it retired from service?

The Grob 109B was known in RAF service as the Vigilant T1. It was retired from service on May 5, 2018.

What was notable about the Grob G 109's construction materials?

The Grob G 109 was the first motor glider constructed using composite materials, specifically glass-reinforced plastic, to receive approval from the Federal Aviation Administration (FAA).

How did the G 109B's design address issues found in the earlier G 109A?

The G 109B incorporated several improvements based on operational experience with the G 109A. These included increased power (95 hp compared to 80 hp), better performance in wet conditions, improved crosswind handling, and increased cockpit space.

Describe the basic airframe configuration of the G 109B.

The G 109B is a low-wing cantilever motor glider featuring a T-tail, wings that can fold and be detached, and side-by-side seating with dual controls. It is primarily constructed from glass-reinforced plastic and has a taildragger undercarriage arrangement.

How did the cockpit entry system differ between the G 109A and the G 109B?

The G 109B features two individual perspex doors that open upwards for cockpit entry and exit. This was a modification from the original G 109A's one-piece canopy.

What features contribute to pilot comfort in the G 109B's cockpit?

The cockpit of the G 109B can be heated when the engine is running, and the seat backs are adjustable. Cushions of varying thickness can also be inserted to accommodate different body sizes.

What is the typical empty weight and maximum takeoff weight of the G 109B?

The typical empty weight of the G 109B is around 1,870 pounds (850 kg), with a maximum load capacity that varies but is often around 200 kg. The maximum takeoff weight is specified as 850 kg (1,874 lb).

What specific modification did the RAF obtain regarding the G 109B's weight?

The RAF obtained a dispensation from Grob to operate the military variant, the Vigilant T1, at a Maximum All Up Weight (AUW) of 908 kg, which provided an additional 59 kg of useful load. This was permissible without structural changes as center of gravity constraints were not exceeded.

What is the typical cruising speed range and top speed of the Grob G 109B?

The G 109B has a cruising speed in the range of 60–100 knots (110–190 km/h) with its 95 horsepower engine. Its top speed can reach up to 130 knots (240 km/h).

What is the origin of the G 109B's engine, and what are its capabilities?

The engine is based on a Porsche air-cooled car unit. Grob increased its cylinder bore to a 2.5-liter capacity. The engine can be shut down in flight, and its propeller blades can be feathered, allowing the aircraft to function as a pure glider.

What is the maximum glide ratio of the Grob G 109 when operating as a glider?

When the engine is shut down and the propeller feathered, the Grob G 109 can achieve a best glide ratio of approximately 1:28.

What is the Time Before Overhaul (TBO) for the Porsche-derived engine used in the G 109B?

The TBO for the modified Porsche-derived engine has been increased to 1,600 hours. Many examples have exceeded 4,000 hours in service when operated on condition.

How is the Grob G 109B classified under UK Civil Aviation Authority (CAA) regulations?

Under the UK CAA LASORS document, the G 109B can be classified as either a touring motor glider (TMG) or a self-launching motor glider (SLMG).

What specific engine powers the G 109B, and what is its output?

The G 109B is powered by a Grob 2500 E1 engine. This is a horizontally opposed, four-cylinder, air-cooled petrol engine that produces approximately 95 bhp (71 kW) at 2,950 rpm.

Describe the propeller system used on the G 109B.

The aircraft uses a two-bladed, manually operated variable-pitch propeller driven directly by the engine. It features three pitch settings: 'Fine' for takeoff and general flying, 'Coarse' for cruising, and 'Feathered' for gliding with the engine off.

What is the purpose of the carburettor heat system on the G 109B?

Carburettor heat can be supplied to the twin carburettors on the G 109B's engine to prevent or mitigate icing conditions.

What type of flight controls are used in the Grob G 109, and are they duplicated?

The G 109 utilizes conventional flight controls, which are duplicated for both seats, ensuring that both the pilot and co-pilot have access to essential controls.

What other functions do the rudder pedals in the G 109 control?

In addition to controlling the rudder, the rudder pedals in the Grob G 109 also operate the wheel brakes. They are also adjustable forward and backward to accommodate pilots of different leg lengths.

How are airbrakes used in the Grob G 109?

Airbrakes are employed in the G 109 to increase the aircraft's rate of descent during the landing approach. They can also be used to limit the airspeed to the never-exceed (Vne) speed if necessary.

When was the Vigilant T1 introduced into RAF service, and what aircraft did it replace?

The Vigilant T1 variant was introduced into RAF service in 1991, replacing the Slingsby Venture aircraft.

What was the role of the Royal Air Force Central Gliding School in relation to the Vigilant T1?

The Central Gliding School, located at RAF Syerston, was responsible for training Volunteer Gliding Squadron (VGS) instructors. It also provided standards checking, developed syllabi, and offered engineering support for the Vigilant T1 fleet.

When did the Australian Air Force Cadets begin using the Grob 109 for pilot training?

The Australian Air Force Cadets adopted the Grob 109 for pilot training purposes during the early 2000s, and the type remains in use there.

What led to the grounding of the RAF Vigilant fleet in April 2014?

The RAF Vigilant fleet was grounded starting in April 2014 due to ongoing maintenance issues related to airworthiness certification.

What was the outcome of the recovery plan for the Vigilant fleet in 2016?

In 2016, a recovery plan was implemented, reducing the operational Vigilant fleet to 15 aircraft nationwide. These aircraft were operated from 'regional hubs' by four VGS units.

What happened to the majority of the RAF's Vigilant T1 fleet after its retirement?

Following the retirement of the Vigilant T1 from RAF service on May 5, 2018, two aircraft were retained by the RAF for specific purposes. The remaining fleet was transferred to the Defence Equipment Sales Authority, deregistered, and sold to the civilian operator Aerobility in 2020.

What distinguished the initial G 109 prototype aircraft from later production models?

The first two prototype aircraft, designated G 109, had a shorter wingspan of 15 meters (49 ft) compared to the later production aircraft.

What engine and propeller configuration characterized the G 109A variant?

The G 109A was equipped with a 2,000 cc Limbach Flugmotoren flat-four engine producing 80 horsepower (60 kW) at 3,400 rpm. Its wingspan was increased to 16.6 meters (54 ft).

Why were some G 109A airframes fitted with a different engine and propeller system?

The initial 80 hp engine had marginal power reserves in hot conditions or when flying through rain. To address this, approximately 30 G 109A airframes were fitted with a larger 2,400 cc, 90 hp Limbach engine and an electrically controlled variable-pitch propeller.

How many G 109A motor gliders were produced in total?

A total of 151 G 109A motor gliders were manufactured.

What was the G 109Ar modification, and what engine did it utilize?

The G 109Ar was a modification applied to two Grob 109A aircraft by the Aero Club Valkenburg. These were fitted with a Rotax boxer-type engine to enhance performance, particularly on short runways, and improve reliability. Three G 109A aircraft were converted to the G 109Ar standard.

What were the primary design changes implemented in the G 109B variant compared to the G 109A?

The G 109B featured an increased wingspan to 17.4 meters (57 ft), replaced the G 109A's single-piece canopy with opening doors for easier cockpit access, and repositioned the main landing gear rearward to improve weight distribution on the tailwheel.

What modifications have been made to some G 109B aircraft in Germany?

Some G 109B aircraft in Germany have been fitted with turbocharged engines and structural strengthening to the fuselage, adapting them for aero-towing gliders.

What is the 'Ranger' variant of the Grob G 109?

The Ranger variant is an increased Maximum Takeoff Weight (MTOW) utility version. It is equipped with cameras in extended leading edge root fairings and has provisions for a ventral pannier to carry search and rescue equipment.

What specific modifications were made to the Grob 109B to create the Vigilant T1 for the RAF?

The Vigilant T1 modifications included the addition of a landing light, an increase in the maximum all-up mass (AUM) to 908 kg, and the installation of a throttle control in the left-hand seat.

What is the 'G 109 Able' designation?

The G 109 Able refers to the Vigilant T1 when equipped with a Rotax 912is3 engine, as modified by the charity Aerobility.

What is the Thai military designation for the Grob G 109?

The Royal Thai Armed Forces use the designation B.R.2 for the Grob G 109.

Which organizations currently operate the Grob G 109?

As of 2014, the Australian Air Force Cadets operate the Grob G 109. Historically, the Royal Air Force in the UK was a primary user, and the Royal Thai Air Force also operates the type.

What are the dimensions of the Grob G 109B?

The G 109B has a length of 8.1 meters (26 ft 7 in), a wingspan of 17.4 meters (57 ft 1 in), and a height of 1.8 meters (5 ft 11 in).

What is the wing area and airfoil used on the Grob G 109B?

The G 109B has a wing area of 19 square meters (200 sq ft) and utilizes the Eppler E 580 airfoil, which has a thickness of 16.1%.

What is the maximum takeoff weight and empty weight of the G 109B?

The maximum takeoff weight for the G 109B is 850 kg (1,874 lb), while its empty weight is 620 kg (1,367 lb).

What is the fuel capacity of the Grob G 109B?

The Grob G 109B has a fuel capacity of 100 liters (26 US gallons or 22 imperial gallons).

What is the maximum range of the Grob G 109B?

The G 109B has a maximum range of 1,500 kilometers (930 miles or 810 nautical miles) when flown at economical cruise speed with maximum fuel.

What is the service ceiling and never-exceed speed (Vne) of the Grob G 109B?

The service ceiling for the G 109B is 6,000 meters (20,000 ft), and its never-exceed speed (Vne) is 240 km/h (150 mph or 130 knots).

What is the maximum glide ratio and rate of climb for the G 109B?

The G 109B has a maximum glide ratio of 28, achieved at 115 km/h. Its rate of climb is 3.3 meters per second (650 ft/min).

What are the listed avionics for the Grob G 109B?

The avionics listed for the Grob G 109B include VOR, DME, ADF, a Variometer, and a Transponder.

What is the takeoff and landing run required for the Grob G 109B?

The takeoff run for the Grob G 109B is approximately 196 meters (643 ft), and the landing run is around 200 meters (656 ft).

What is the power-to-mass ratio of the Grob G 109B?

The power-to-mass ratio for the Grob G 109B is 0.079 kW/kg (or 0.048 hp/lb).

Grob G 109 Wiki: Grob G 109: The Composite Glider's Ascent

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Overview

A Pioneering Motor Glider

The Grob G 109 is a distinguished light aircraft developed by Grob Aircraft AG in Germany. First taking flight in 1980, it represents a significant advancement in aviation design, particularly for its innovative use of composite materials. This two-seat, self-launching motor glider is characterized by its side-by-side seating arrangement, offering excellent visibility for both pilot and passenger.

Historical Significance

The G 109 was the first motor glider constructed with composite materials to achieve approval from the Federal Aviation Administration (FAA). This technological leap underscored its importance in the evolution of light aircraft manufacturing, paving the way for future designs prioritizing strength, lightness, and aerodynamic efficiency.

Global Reach and Service

Beyond its civilian applications, the Grob G 109, specifically the G 109B variant known as the Vigilant T1 in Royal Air Force (RAF) service, played a crucial role in training. It was instrumental in educating air cadets in the UK and was also adopted by the Australian Air Force Cadets, demonstrating its versatility and reliability across different operational contexts.

Design Philosophy

Composite Construction

The G 109's primary structure is predominantly composed of glass-reinforced plastic (GRP), a composite material offering a superior strength-to-weight ratio compared to traditional metal construction. This choice significantly contributes to the aircraft's performance and handling characteristics.

Aerodynamic Configuration

The aircraft features a low-wing cantilever design, a T-tail configuration for stability, and wings that can be folded and detached for ease of storage and transport. This adaptability enhances its utility for private owners and flight schools.

Ergonomic Cockpit

The G 109B variant introduced significant cockpit improvements over the earlier G 109A. Notably, the original one-piece canopy was replaced with individual upward-opening doors, enhancing accessibility. The cockpit is heated, and the seat backs are adjustable, allowing for greater pilot and passenger comfort during extended flights.

Technical Details

G109B / Vigilant T1 Configuration

The G 109B is a low-wing cantilever motor glider. Its design includes a T-tail, folding wings, and a taildragger undercarriage arrangement. The cockpit accommodates two occupants side-by-side, with dual controls available. Entry is facilitated by two upward-opening perspex doors, a notable improvement for ease of access.

Weight and Load Capacity

The typical empty weight of the G 109B is approximately 620 kg (1,367 lb). While the standard maximum takeoff weight is 850 kg (1,874 lb), the RAF variant, Vigilant T1, received specific modifications allowing for an increased maximum all-up mass (AUM) of 908 kg, providing an additional 59 kg of useful load without compromising the center of gravity limits.

Landing Gear and Handling

The aircraft utilizes a conventional taildragger landing gear configuration. The rudder pedals are adjustable to accommodate pilots of varying leg lengths. Airbrakes are incorporated to manage descent rates during landing approaches and to limit airspeed to V_ne (velocity never exceed) when necessary.

Propulsion System

The Grob 2500E1 Engine

The G 109B is powered by a Grob-built 2,500 cc, four-cylinder, air-cooled, horizontally-opposed piston engine, designated the Grob 2500E1. This unit, derived from a Porsche automotive engine, produces approximately 95 horsepower (71 kW) at 2,950 rpm. The engine's time before overhaul (TBO) has been extended through technical notes, with many units exceeding 4,000 hours in service.

Variable-Pitch Propeller

A two-bladed, manually operated variable-pitch propeller is driven directly by the engine. This system allows for three pitch settings: 'Fine' for takeoff and general flying, 'Coarse' for cruising, and 'Feathered' for gliding with the engine shut down. Carburetor heat is available for the twin carburetors to mitigate icing risks, and an electric fuel pump is utilized.

Flight Controls

Duplicated Systems

The G 109 employs conventional aircraft flight controls, which are duplicated for both the pilot and passenger seats. This includes the primary flight controls and, in most production G 109s, the throttle, which is accessible from the left-hand seat in the Vigilant T1 variant.

Airbrakes and Speed Management

The aircraft is equipped with airbrakes, which serve a dual purpose: increasing the rate of descent during landing approaches and limiting airspeed to V_ne (velocity never exceed) if required. This feature enhances the aircraft's operational flexibility and safety margins.

Operational History

Royal Air Force Vigilant T1

The Vigilant T1 variant was introduced into RAF Volunteer Gliding Squadrons (VGS) in 1991, succeeding the Slingsby Venture. It was used to train Air Training Corps and Combined Cadet Force cadets, bringing them to solo standard. The Central Gliding School at RAF Syerston also utilized the Vigilant for instructor training and support.

Australian Air Force Cadets

In the early 2000s, the Australian Air Force Cadets adopted the Grob 109 for their pilot training programs. The type remains in service with this organization, highlighting its enduring utility in cadet aviation training.

Service Pause and Retirement

The RAF Vigilant fleet experienced operational pauses due to airworthiness certification issues. A recovery plan in 2016 reduced the fleet to 15 aircraft. The Vigilant T1 was officially retired from RAF service on May 5, 2018, with most of the remaining fleet transferred to the Defence Equipment Sales Authority and sold to the charity Aerobility in 2020.

Key Variants

G 109 / G 109A

The initial prototypes were designated G 109, featuring a shorter wingspan of 15 meters. The G 109A followed, with an increased wingspan of 16.6 meters and powered by a 80 hp Limbach engine. Some G 109A models were later upgraded with a 90 hp engine and a variable-pitch propeller for improved performance.

G 109B / Vigilant T1

The G 109B represented a significant evolution, featuring a further increased wingspan of 17.4 meters, improved cockpit access via doors, and revised landing gear placement. It was powered by the 95 hp Grob 2500E1 engine. The RAF's Vigilant T1 is a modified version of the G 109B, incorporating features like a landing light and a throttle for the left-seat instructor.

Other Designations

The 'Ranger' variant was an increased MTOW utility version, often equipped for surveillance. The 'G 109 Able' is a Vigilant T1 modified with a Rotax 912is3 engine by the charity Aerobility. The Royal Thai Armed Forces designated the G 109 as the 'B.R.2'.

Operators

Australia

The Australian Air Force Cadets have operated the Grob 109 for pilot training purposes since the early 2000s and continue to utilize the type.

United Kingdom

The Royal Air Force (RAF) historically operated the Vigilant T1 variant through its Volunteer Gliding Squadrons (VGS) and the Central Gliding School. The fleet was retired in 2018.

Thailand

The Royal Thai Armed Forces have utilized the Grob G 109, designating it as the B.R.2.

Specifications

Performance and Dimensions

The G 109B showcases impressive performance metrics for its class:

Characteristic	Specification
Crew	2
Length	8.1 m (26 ft 7 in)
Wingspan	17.4 m (57 ft 1 in)
Height	1.8 m (5 ft 11 in)
Wing Area	19 m² (200 sq ft)
Airfoil	Eppler E 580 (16.1%)
Empty Weight	620 kg (1,367 lb)
Max Takeoff Weight	850 kg (1,874 lb)
Fuel Capacity	100 L (26 US gal; 22 imp gal)
Powerplant	1 × Grob 2500E1, 71 kW (95 hp)
Propellers	Hoffmann HO-V 62 R/L 160 BT, 2-bladed variable-pitch
Cruise Speed (Max)	205 km/h (127 mph, 111 kn)
Cruise Speed (Economical)	180 km/h (110 mph, 97 kn)
Stall Speed	73 km/h (45 mph, 39 kn)
Never Exceed Speed (V_ne)	240 km/h (150 mph, 130 kn)
Range	1,500 km (930 mi, 810 nmi)
Service Ceiling	6,000 m (20,000 ft)
g limits	+5.3 / -2.65
Max Glide Ratio	28 at 115 km/h (71 mph, 62 kn)
Rate of Climb	3.3 m/s (650 ft/min)
Rate of Sink	1.1 m/s (220 ft/min) at 105 km/h (65 mph, 57 kn)
Wing Loading	44.7 kg/m² (9.2 lb/sq ft)
Power/Mass	0.079 kW/kg (0.048 hp/lb)
Take-off run	196 m (643 ft)
Landing run	200 m (656 ft)

Avionics Suite

The standard avionics fit for the Grob G 109 typically includes:

VOR (VHF Omnidirectional Range)
DME (Distance Measuring Equipment)
ADF (Automatic Direction Finder)
Variometer (Vertical Speed Indicator)
Transponder

Related Aircraft & Concepts

Comparable Aircraft

The Grob G 109 shares design principles and operational roles with other notable aircraft:

Diamond HK36 Super Dimona
Fournier RF-9
Valentin Taifun

Gliding Concepts

Understanding the G 109 also involves familiarity with core aviation principles:

Gliding
Motor Gliders
Composite Aircraft Construction

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References

Grob website Retrieved 23 August 2008

Rotax Aero Club Valkenburg

A full list of references for this article are available at the Grob G 109 Wikipedia page

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Disclaimer

Important Notice

This page has been generated by an Artificial Intelligence, drawing upon publicly available data from Wikipedia. It is intended for educational and informational purposes only, providing a comprehensive overview of the Grob G 109 motor glider.

This is not professional aviation advice. The information presented here is not a substitute for official aircraft documentation, pilot training, or consultation with certified aviation professionals. Always adhere to manufacturer guidelines, regulatory standards, and expert advice for all aviation-related activities.

The creators of this page are not liable for any inaccuracies, omissions, or consequences arising from the use of this information. Aviation safety is paramount; always prioritize certified training and official resources.

Grob G 109: The Composite Glider's Ascent

💡 Dive in with Flashcard Learning! 💡

Overview ℹ️

✈️ A Pioneering Motor Glider

📜 Historical Significance

🌍 Global Reach and Service

Design Philosophy 📐

🏗️ Composite Construction

🛩️ Aerodynamic Configuration

💺 Ergonomic Cockpit

Technical Details ⚙️

🎛️ G109B / Vigilant T1 Configuration

⚖️ Weight and Load Capacity

🛬 Landing Gear and Handling

Propulsion System ⚙️

🚀 The Grob 2500E1 Engine

🔄 Variable-Pitch Propeller

Flight Controls 🕹️

🎛️ Duplicated Systems

💨 Airbrakes and Speed Management

Operational History 📈

🇬🇧 Royal Air Force Vigilant T1

🇦🇺 Australian Air Force Cadets

⚠️ Service Pause and Retirement

Key Variants 🗂️

➡️ G 109 / G 109A

➡️ G 109B / Vigilant T1

➡️ Other Designations

Operators 🌍

🇦🇺 Australia

🇬🇧 United Kingdom

🇹🇭 Thailand

Specifications 📏

🧮 Performance and Dimensions

📡 Avionics Suite

Related Aircraft & Concepts 🔗

🛩️ Comparable Aircraft

🪶 Gliding Concepts

Teacher's Corner 🧑‍🏫

Edit and Print this course in the Wiki2Web Teacher Studio

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❓ Test Your Knowledge! ❓

Gamer's Corner 🎮

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References

📜 References

Feedback & Support 👍

To report an issue with this page, or to find out ways to support the mission, please click here.

Disclaimer ⚠️

📜 Important Notice

Dive in with Flashcard Learning!

Overview

A Pioneering Motor Glider

Historical Significance

Global Reach and Service

Design Philosophy

Composite Construction

Aerodynamic Configuration

Ergonomic Cockpit

Technical Details

G109B / Vigilant T1 Configuration

Weight and Load Capacity

Landing Gear and Handling

Propulsion System

The Grob 2500E1 Engine

Variable-Pitch Propeller

Flight Controls

Duplicated Systems

Airbrakes and Speed Management

Operational History

Royal Air Force Vigilant T1

Australian Air Force Cadets

Service Pause and Retirement

Key Variants

G 109 / G 109A

G 109B / Vigilant T1

Other Designations

Operators

Australia

United Kingdom

Thailand

Specifications

Performance and Dimensions

Avionics Suite

Related Aircraft & Concepts

Comparable Aircraft

Gliding Concepts

Teacher's Corner

True or False?

Test Your Knowledge!

Gamer's Corner

Discover other topics to study!

References

Feedback & Support

Disclaimer

Important Notice