BO105 Milestones from 1963 until Today

1963 until 1969

1963, May

First public information about the light-twin-engine helicopter BO105 have been given by Prof. Dr. Ludwig Bölkow during Le Bourget Air show. Remark: BO105 stands for: BO = Bölkow, 105 was a running project number.

 


1966, January

First Flight of hingeless rotor “System Bölkow” on Alouette II helicopter at Ottobrunn / Munich.

 

 

 

 

1966, August

BO105 V1 (1st prototype) Ground Test Vehicle at Ottobrunn / Munich.

 


1967, Feb. 16th

BO105 V2 (2nd prototype) Maiden Flight by Bölkow test pilot Wilfried von Engelhardt. This first flight took 18 minutes and the project manager Mr. Emil Weiland stated in his report that the helicopter performed as expected. The V2 was equipped with 2 Allison T63 engines, the military variant of the later civil variant Allison 250 C18 / 20.

 


1967, Dec 20th

 

BO105 V3 (3rd prototype) First flight equipped with 2 BMW 6022 engines. The BO105 V3 was equipped with 2 BMW 6022 – A3 (2x MTU 6022 –A3) engines. The BO105 V3 is now exhibited at the Hubschraubermuseum in Bückeburg / Germany.



Turboshaft Engine BMW 6022 – MAN Turbo 6022 – MTU 6022

On the basis of the experience with the 6002 and 6012 small gas turbines, the MTU 6022 shaft power engine was developed in the mid-60s. Its power range comprised 192 to 276 kW (220 to 375 HP).

Its wide power range and very low proneness to malfunction made the MTU 6022 a multi-purpose engine which was, for example, used in cable skips on a delta dike-building in the Netherlands and as generator drive unit for the Spica II fast patrol boats of the Swedish Navy.

The MTU 6022 – A3 was also successfully tested as a power system in the prototype of the MBB BO105 V3 helicopter.

A modified version of the engine served as power system for a MAN experimental truck. Production of the engine has now ceased.

(Reference: MTU Aero Engines Germany)



Description & technical Data of BMW 6022 – A3 / MTU 6022 – A3

The engine comprises a single-shaft compressor with two radial stages, a single-tube combustion chamber and a three-stage axial turbine. The reduction gearbox is flanged to the compressor casing. Via two auxiliary shafts and a common idles gear, the turbine drives the power output gear.


 

Max. power (100%)

Specific fuel consumption (100%)

Airflow

Pressure ratio

Take-off speed

Turbine speed

 

Dimensions:

Length

Max. diameter

Weight

kW 276 / HP 375

g/kW h 424

kg/s 1,91

6,4 : 1

1/min 6000

1/min 41900

 

 

mm 1194

mm 670

kg 83

 

Many thanks to the PR Department of MTU Aero Engines Germany for providing me with this information.


1968

All together 6 prototype helicopters have been manufactured in order to fulfil the necessary certification requirements of the Luftfahrt Bundesamt (LBA) in Germany and Federal Aviation Authorities (FAA) in USA.

With prototype BO105 V6 the required crash test has successfully performed.




 

1969, May 1st

neu

First Flight of BO105V4

Took place at the company MBB helipad at Munich-Ottbrunn.

 

1969

BO105 – The first German Series Helicopter

Increasing activities at the MBB Heliport at Ottobrunn shows the big interest for the world’s first light twin helicopter, the BO105.


 

The picture shows from the left to the right: In the Air the first series helicopter, purchased by the Vertol Division of Boeing (USA) and the BO105 V3. On Ground: The BO105 V2 and BO105 V4. Have a close look the V4, it shows the helicopter has vertical fins on the horizontal stabilizer. Many thanks to the colleague of mine from which I received this very interesting Picture.



1970 until 1979

 

1970, Oct 13th

BO105 A - LBA Certification No. 3025

  • LBA TCDS-No. and Approval-No. 3025
  • Maximum Gross Weight 2,100 KGs
  • 2 x Rolls Royce Allison 250-C18 Engines
  • Main Rotor Transmission ZF – FS 72A
  • Hingeless Rotor System with Composite Rotor Blades
  • Modular Fuselage Design with Use of Composite Material (valid for all Versions)
  • Fail Safe and System Redundancy Design (valid for all versions)

 

 

1971

BO105 with tail rotor blades and horizontal stabilizer made of carbon fiber

In the early 70s MBB experimented with carbon fiber, a strong, lightweight but high-strength material. The picture shows the BO105 C, SN0001, equipped with tail rotor blades and horizontal stabilizer made of carbon fiber composite material.

 

 

1971, Aug 23rd

BO105 C - LBA Certification

  • Maximum Gross Weight 2,100 KGs
  • 2x Rolls Royce Allison 250-C20 Engines

 

 

1971, Dec 22nd

BO105 C23 – LBA Certification

  • increased Maximum Gross Weight 2,100 to 2,300 KGs

 

 

1972, April

BO105 C - FAA Certification

  • Maximum Gross Weight 2,100 KGs
  • 2 x Rolls Royce Allison 250-C20 Engines
  • Main Rotor Transmission ZF – FS 72A

 

 

1972, June

BO105 Production Agreement Philippines

Contract with Philippine Aerospace Development Corporation (PADC) for total 40 BO105 helicopters (complete, semi-know-down and know- down configuration).

 

 

1972, June 30th

BO105 – Handover of 4 Helicopters to the German Border Police (Bundesgrenzschutz)

Within the frame of a big ceremony, on June 30th 1972, MBB handed over four BO105 C helicopters to the German Border Police. The following serial number have been delivered::

·         D-HGSA – SN 0012

·         D-HGSB – SN 0013

·         D-HGSC – SN 0014

·         D-HGSD – SN 0015

The German Border Police was beside the Federal Police of Bavaria and der German Automobile Club (ADAC) one of the launch customers.

 

1972, July

BO105 D – CAA Certification

  • Maximum Gross Weight 2,300 KGs
  • 2 x Rolls Royce Allison 250-C20 Engines
  • Modified electrical wiring according to CAA requirement for IFR

 

 

1972, October

BO105 C23 - FAA Certification

  • Maximum Gross Weight 2,300 KGs
  • 2 x Rolls Royce Allison 250-C20 Engines

 

1973, September

BO105 V4 – HGH reached 200 kt

In the time between 1973 and 1975 MBB conducted a High Speed Research Programme with the BO105. On September 25th 1973 the modified BO105 HGH reached a speed of 200 kt. HGH stands for Hoch-Geschwindigkeits-Hubschrauber (High Speed Helicopter).

The below picture shows the first version of the HGH, the BO105 V4, without wings.


1973, September

BO106 – SN 84 – Maiden Flight

On September 25th 1973 the Chief Test Pilot Mr. Siegfried Hoffmann and the Chief Flight Test, Mr. Hans Glöckl, conducted the first flight on the BO106. The BO106 is the enlarged version of the BO105. The helicopter was extended in the front section of the cabin, whereby the structure behind the rear cabin wall as well as the rotor system and drive system remain unchanged.

The technical data of the BO106:

  • Max Take off Weight: 2,300 kg
  • 1 pilot / 6 passengers
  • 2 RR Allison 250-C20B engines
  • Main Rotor Gear Box ZF – FS 72
  • Range 560 km


 

The below picture shows the airframe just coming out of the production. Many thanks to Franz Paula from whom I received the picture.



Remark:

In 1981 I sold the BO106 to the DRF. The DRF converted the BO106 back to a normal BO105.

On November 18th 1993 this helicopter with the serial number SN 84 went out of service with a total of 2.292 flight hours.


1974, April 20th

BO105 C, S1, - D-HABV - Non-Stop Long-Distance Record Flight

On April 20th 1974 Chief Pilot Siegfried Hoffman and Flight Test Engineer Adam Teleki performed within the frame of the 1,000 hours endurance test a Non-Stop Long-Distance Flight over 1.714,537 km from Munich / Germany to Spain with the standard BO105 C, S-1, powered with two Allison 250-C18 engines.
The BO105, S1, was equipped with 2 long range fuel tanks (standard optional equipment), each with a capacity of 200 litres, mounted in the rear cargo compartment and 2 long range fuel tanks mounted in the rear cabin, instead of the 3-pax seat bench, with special mountings.

With this arrangement the standard fuel capacity of 640 litres was increased by another 800 litres, totally to 1,440 litres.

The flight routing was:

From Munich-Ottobrunn / Germany via St. Gallen /Switzerland – Geneva / Switzerland - Pyreneans /Spain passed by Madrid Spain to Hinohoja del Duque / Spain (the alternative landing place to scheduled Seville / Spain).



The Fédération Aéronautique Internationale confirmed this Non-Stop Long-Distance Flight Record with the Diplôme de Record.


1974, December

BO105 CB - RNLAF -Netherlands

Contract between RNLAF and MBB for 30 BO105 CB helicopters.


1975, January

BO105 CB Licence Production Agreement Indonesia

Contract with Pertamina followed by PT Nurtanio in Bandung for 121 BO105CB helicopters.

  • The Production Agreement was signed between Prof. Dr.-Ing. Habibie and Prof. Dr. Ludwig Bölkow
  • This agreement was the essential milestone to built up the Indonesian Aircraft Industry


1975, March

BO105 V4 – HGH reached 400km/h

On March 4th 1975 the modified BO105 HGH, reached the record speed for of 404 km/h. The BO105 HGH had a main rotor head with a cowling and wings with a total span of 6,20 m.


 

Remark:

After these successful experimental flights the BO105 HGH has been converted back to the previous BO105 V4.


1976, November

BO105 CB - LBA Certification

  • Maximum Gross Weight 2,300 KGs
  • 2x Rolls Royce Allison 250-C20B Engines

 


1977, January

BO105 CB - FAA Certification

  • Maximum Gross Weight 2,300 KGs
  • 2x Rolls Royce Allison 250-C20B Engines

 

 

1977, May

BO105 CS - LBA Certification

  • Maximum Gross Weight 2,300 KGs
  • Stretched Airframe by 10 inches (25cm)


1977, September

BO105 CS – FAA Certification

  • Maximum Gross Weight 2,300 KGs
  • Stretched Airframe by 10 inches (25cm)


1977, December

BO105 M (VHB)

Contract between the German Ministry of Defence and MBB over 100 Verbindungshubschrauber - VBH (Light Observation Helicopter)



1978, Dec 12th

BO105 P (PAH 1)

Contract between the German Ministry of Defence and MBB over 212 Panzerabwehrhubschrauber –PAH1 (Anti-Tank Helicopter)

1979, April

BO105L – S-423 – Maiden Flight

On April 12th 1979 the MBB Test Pilot Udo Hausen and the Flight Test Engineer Dieter Bender conducted the first flight on the BO105L. The BO105L was designed to compete with the French “Lama”. The BO105L was equipped with the stronger RR-Allison 250 C28 engines instead of the C20 engines and the FS112 main gear box coming from the BO105 P - PAH 1, the German Anti Tank Helicopter.


1979, June

BO105 Purchase and Licence Agreement Spain

Contract between the Spain Ministry of Defence and MBB covering 60 BO105 helicopters for FAMET. Licence Partner war the company CASA (Construcciones Aeronauticas S.A.). Today CASA is integrated in Eurocopter Spain.

 

 

1979, October

BO105 M (VBH)

1st Delivery of the Light Observation Helicopter for the German Army Aviation (100 a/c in total)

  • Maximum Gross Weight 2,300 KGs
  • Main Rotor Transmission ZF - FS 110
  • Special Electric and Wiring according to Army Aviation’s Requirements

 

 

1979, November

BO105 P (PAH 1)

1st Delivery of the Anti Tank Helicopter for the German Army Aviation (212 a/c in total)

  • Maximum Gross Weight 2,400 KGs
  • 2 MTU Licence Production Engines of the Rolls Royce Allison 250-C20B Engines
  • Main Rotor Transmission ZF – FS 112
  • YAW Stability Augmentation System (YAW SAS)
  • HOT Anti-Tank Missile System
  • APX Sighting System



1980 until 1989

1980, February

BO105 CB/CBS - LBA Certification

  • Maximum Gross Weight 2,400 KGs
  • 2 x Rolls Royce Allison 250-C20B Engines
  • Main Rotor Transmission ZF – FS 72B
  • Stretched Airframe by 10 inches (25cm) at CBS Version

 

 

1980, November

BO105 CB/CBS - FAA Certification

  • Maximum Gross Weight 2,400 KGs
  • 2 x Rolls Royce Allison 250-C20B Engines
  • Main Rotor Transmission ZF – FS 72B
  • Stretched Airframe by 10 inches (25cm) at CBS Version


1981, August

BO105 M - Free-Style World Championship

At the 4th World Helicopter Championships in Piotrkow Trybunalski (Poland), from August 10th – 23rd 1981, Captain Karl Zimmermann from the Army Flight Regiment No. 16 in Celle, Germany, won the title in the free-style discipline with his BO105 M (scout helicopter).

 

 

1984, March

BO105 CB-4/CBS-4 - LBA Certification

  • Maximum Gross Weight 2,500 KGs
  • 2 x Rolls Royce Allison 250-C20B Engines
  • Main Rotor Transmission ZF – FS 72B
  • Stretched Airframe by 10 inches (25cm) at CBS Version


1984, May

BO105 CB-4/CBS-4 - FAA Certification

  • Maximum Gross Weight 2,500 KGs
  • 2 x Rolls Royce Allison 250-C20B Engines
  • Main Rotor Transmission ZF – FS 72B
  • Stretched Airframe by 10 inches (25cm) at CBS Version

 

 

1984, June

BO105 M (VBH)

  • 100th Delivery of the VBH (Light Observation Helicopter)


1984, June

BO105 CB-3 – ATH Sweden

Contract for Anti-Tank-Helicopter (ATH) with the Swedish Army

  • HELITOW Weapon System including
  • Stabilized Sight System
  • Missile Launching and Guidance System

 

 

1984, September

BO105 P (PAH 1)

On September 7th the last of a total 212 Anti-Tank-Helicopter of the first generation (PAH 1) of the type BO105 P was handed over to the German Army Aviation at the MBB facility in Ottobrunn in the presence of numerous guests of honour from politics, Ministry of Defence, representatives from the Armed Forces and from Industry.


1984, October until

March 1985

 

Ice Age for PolarHeli 1 – BO105 CB

The MBB helicopter BO105 CB, christened “PolarHeli 1” carried out transfer, exploration, supply and measurement flights in the Antarctic as a part of the Antarctic Research Program, supported by the Federal Ministry for Research and Technology. The BO105 CB was specially equipped for its role with emergency floats, a litter, a rotor blade folding kit, a long-range fuel tank as well as special navigation and communication systems. Its “home base” during this expedition was the German research vessel “Polarstern”.

 


1990 until 1999

1991

BO105 P (PAH 1) - KWS 1 Programme

Combat Improvement Programme for ATH of the German Army Aviation

  • New Main Rotor Blades Advanced Technology
  • HOT-2 Anti-Tank Missile System including Digital Weapon System, Light Weight Launching System and HOT-2 Missiles with greater Armorpiercing Performance
  • Improved Engine Air Intake and Oil Cooling System

1991 September

BO105 PolarHeli

The helicopter operator Helicopter-Service-Wasserthal has stationed a BO105 helicopter, called “PolarHeli” on Forschungsschiff Poloarstern. Between August 1st and October 15th ,1991 the International Arctic Ocean Expedition has been realized. During that this period the BO105 PolarHeli crossed the North Pole on

September 7th 1991.

Deutsche Schiffspost FS Polarstern Polarexpeditionen dated September 7th, 1991


1992, February

25th Anniversary of the BO105

In February 16th, 1967 the maiden flight took place. Today, 25 years later, over 1,300 BO105 helicopters have been produced and delivered. The BO105 fleet had accumulated over 2,5 million flight hours (status per September 1991).


1993

BO105 CB-5/CBS-5 “EC Super Five” - LBA Certification

  • Upgraded BO105 CBS Version including
  • New Main Rotor Blades Advanced Technology
  • Upgraded Main Rotor Transmission ZF – FS 72E
  • Increased Performances especially at Hover and Single Engine Operation
  • Noise Reduction through new Main Rotor Blades

2000 until today

2001

BO105 Series Production finished after more than 30 Years

With the delivery of the last 17 BO105 CBS-5 helicopters to the Bundesgrenzschutz and furthermore 12 BO105 CBS-5 helicopters to South Korea the successful story of the production of the BO105 has been stopped in favour to the follower, the EC135. In more than 30 year of production 1,404 BO105 helicopters have been produced and delivered.


2003, Feb 27th

BO105 CB-5/CBS-5 Category “A” equivalent - LBA Certification

On February 27th 2003 the LBA granted the “Category A equivalent Certification for the BO105 CB-5/CBS-5, the basis for further EMS Operation.


2005

 

BO105 Flying Red Bull

The two Red Bull BO105 helicopters in Europe were produced in 1974. The BO105 D-HAYA (SN 126) and D-HAYE (SN 140) went first into service with the Police Helicopter Squadron Rheinland - Pfalz. In 2002 the SN 140 and in 2004 the SN 126 have been bought by Action Concept for movie production. In 2005 both helicopters have been bought by Red Bull.

If the Red Bull Helicopters are not on tour, they can be visited at:

Red Bull Hangar-7

Salzburg Airport

Wilhelm-Spazier-Str. 7A

5020 Salzburg / Austria

Phone: +43/662/2197

Email: office@hangar-7.com


2006, September

60th  Anniversary of the Eurocopter Deutschland Plant at Donauwörth

During this event the whole Eurocopter Helicopter palette was shown in the static and the flying Display.

One of the highlights was the breath taking aerobatic show of the BO105 CB, SN 0126, D-HSDM, in the colours of Flying Red Bulls, performed by Captain Rainer Wilke.


2006, November

BO105 CBS with CHARM

On November 23rd 2006 the “Gesellschaft von Freunden des Zentrums für Luft- und Raumfahrt e.V.” awarded the CHARM with the “DLR-Innovationspreis 2006”.

CHARM is a helicopter based remote sensing system. The companies involved in this project are: E.ON Ruhrgas AG, ADLARES and DLR. The whole test programme was performed on a BO105 CBS, SNxxx , D-HBWH provided by Air Lloyd

The BO105 with its clamshell doors is perfect to carry the container mounted CHARM system. (Reference: DLR).


2007, January

BO104 E-4, SN 5087, - Maiden Flight

On January 25th 2007 the Eurocopter test pilot Captain René Nater and the flight inspector Bernhard Röper conducted the first flight on the BO105 E-4. The BO105 E-4 is the modernized and converted version of the former BO105 M – VBH, whose performances are close to those of the civil CB-4 version. The BO105 E-4 is developed for governmental customers.


2007, February

40th Anniversary of the BO105 – A Legend

On February 16th 1967, the BO105 took off for its maiden flight in Ottobrunn near Munich, flown by MBB Chief Test Pilot Baron Wilfried von Engelhardt. The BO105 was the world’s first light twin-engine helicopter and the world’s first helicopter with a hingeless titanium main rotor and composite blades, the “Bölkow-Rotor-System.

With more than 1400 produced helicopters and nearly 7 million accumulated flight hours the BO105 became a legend in the world of helicopters.


2007, March

ADAC honoured its BO105 Helicopters “The Yellow Angels”

After 35 years the ADAC-Rettungsflugwacht (German Automobile Association) retired the last of its four BO105 helicopters and replaced them by the newer type of helicopters the BK117, EC135 and EC145. The new generation of helicopters are compliant with the regulations of the JAR OPS 3 (Joint Aviation Requirements Operations).

The BO105 was over the years a reliable working horse in EMS operation, well known under the brand “Yellow Angel”. (Reference: Eurocopter Deutschland)


2007, April

The Uruguayan Navy received 6 BO105

On April 18th 2007 the Uruguayan Navy received the first of 6 BO105 M helicopters from the BWB (Procurement Branch of the Bundeswehr). The event took place at the Airfield in Faßberg / Germany. (Reference: German Air Force).


2007, April

Delivery of the first 2 BO105 E-4 for the Albanian Defence Ministry

On April 18th 2007 the first 2 BO105 E-4 landed in Tirana / Albania.

The helicopters are a gift from the German Government to the Albanian Government. They have been modernized at Eurocopter Deutschland at Donauwörth and converted from BO105M VBH into BO105 E-4 version, whose performances are close to those of the civil CB-4 version.

The helicopters will be operated in emergency medical services (EMS), search and rescue (SAR) and VIP transport missions.


2007, May

BO105 M joins The Helicopter Museum in UK

The Helicopter Museum at Weston-super-Mare in Sommerset has taken delivery of its newest exhibit on 2nd May 2007, a BO105 M helicopter built by former Messerschmitt Bölkow Blohm (MBB) company in Germany.

The aircraft, a BO105 M, is the world’s first light twin-engined helicopter. Donated by Eurocopter Deutschland (successor company of MBB), the BO105 M, SN 81+00, in service with the German Army Aviation, was handed over to THM Chairman, Capt. Elfan ap Rees, on 19th April in a ceremony at Donauwörth/Germany. (Reference: Eurocopter Deutschland / The Helicopter Museum)


2007, November

BO105 serves EMS in Israel

On 5th November 2007, after intensive training of pilots, mechanics, doctors and medical crews, Lahak Aviation Ltd started successfully the first civil Emergency Medical Service in Israel with two BO105 CBS helicopters. Its first EMS helicopter the BO105 CBS-4, SN 341, already flew two EMS missions, taking two critically injured accident victims to Haifa Trauma Centre. (Reference: Lahak Aviation Ltd.) Foto below: Lahak Aviation Ltd.


2007, November


 

The BO105 celebrates 7 Million Flight Hours on its fleet

40 Year after the maiden flight of the BO105, on February 16th 1967, the BO105 fleet has accumulated over 7 million flight hours. From the very beginning the BO105 was designed as a light twin-engine helicopter and serves in EMS -, Police -, Military -, Off-Shore -, Rescue – and VIP operation with its 1344 delivered helicopters in more than 45 countries worldwide under all climatically conditions.


2010, January

The BO105 as Symbol of Partnership

The BO105 is a donation of Eurocopter Deutschland GmbH to the City of Donauwörth. It symbolizes the long tradition between the company and the city. The new town’s landmark has been unveiled in presence of the Lord Mayor of Donauwörth, Mr. Armin Neudert, Managing Director of Eurocopter Deutschland, Dr. Wolfgang Schoder, the designer Mr. Volker Scupin and some 100 spectators.


2014, May

The BO105 clock up a total of 8 million flight hours

During ILA on 21st May 2014, Airbus Helicopters celebrated with its BO105 customers 8 million flight on the BO105. Since the maiden flight on 17th February 1967, the BO105 has its place in the world of helicopters. The twin-engine light helicopter, with its rigid Bölkow –Rotor-System and the composite rotorblades, the BO105 prove its reliability under tough conditions worldwide.

 

 

2016, June

MBB BO105 – The universal Lightweight

In June 2016 appeared at Motorbuch Verlag the Evolution of the MBB BO105. The authors Bernd Vetter / Frank Vetter have collected and described many unknown details of the MBB BO105. Furthermore many pictures are going with the description, pictures which have never been published before.

The book “MBB BO105” can be purchased under ISBN 978-3-613-03854-7.

 

 

February 16th 2017

new

A look back at the success of the BO105

50 years after the first flight of the BO105 V2 on February 16, 1967, the Royal Aeronautical Society, Munich Branch, held a review of the success story of the BO105 in the premises of the Deutsche Museum at the Flugwerft Oberschließheim.

The event was accompanied by lectures by

·         Dipl. Ing. Josef Unterhitzenberger, Manager of Helicopter Structures i.R. (Formerly MBB)

·         Prof. Dr. Manfred Hajek, EADS Foundation Chair for Helicopter Technology (TUM)

·         Dipl. Kaufmann Andreas Kesselkaul, BO105 Program (Airbus Helicopters Deutschland GmbH)

The BO105, with its innovative technical concept, has become the worldwide sales base with more than 1400 helicopters built. More than 400 BO105s are still in use today.

The service BO105 flies on the Falkland Islands and performs their assignments there. To date, the BO105 fleet has flown more than eight million flights worldwide.

 

 

February 22nd 2017

new

BO105 celebrates Birthday of its first flight

on the occasion of the 50th anniversary of the first flight of the BO105, Airbus Helicopters Deutschland GmbH held a special exhibition in Donauwörth.

In the open-air area, 4 BO105 were shown:

·         BO105 SN 206 - Airbus Helicopter IFR Training Helicopter

·         BO105 - in the painting of the world champion machine by Hptm Charly Zimmermann

·         BO105 - the Flying Bulls from Salzburg

·         BO105 - Special paint on the 50th anniversary of the first flight

In the conference room, the trainees of Airbus Helicopters presented the technical development of the BO105 with diagrams and exhibits.

A special highlight of the exhibition was the authentic replica of the BO103a. The trainees, with their instructor, Volker Eisenhofer, have imitated this model in 15 months. To you, my full appreciation for this unique, successful work.