Nederlandse Modelbouw en Luchtvaartsite

Dutch Modelling and Aviation

In Memoriam

Klaas Willem Jonker
(Wilko)
† April 30, 2018

On Monday 30 April 2018, Wilko Jonker died after a long illness at the age of 58. He leaves behind a wife and two children. The Dutch military aviation and plastic modeling were his hobby and on this website he shared all the knowledge he has collected over the years. His hobby has been able to distract him from the persistent disease in his body until the last week of his life. The contacts with other hobbyists were a major support for him.

This website will be maintained by different people for as long as possible, so that other enthusiasts can continue to benefit from extensive content.

(Glenn-)Martin B.10 (139/166)

History

Like the MB during the 1920s and early thirties of the twentieth century the Martin B-10 series set standard for land bombers. The design was the first successful military application of the new airframe technology and had a streamlined monocoque fuselage, propellers with variable pitch adjustment, thick metal wings with lift enhancing flaps, integral fuel tanks and a retractable landing gear.

The B-10 was designed in response to an Air Corps bomber specification from late 1929. Besides Martin also Fokker, Keystone, Douglas, Ford and Boeing, presented a design or prototype.

The first Martin's proposal for a conventional biplane was rejected by the USAAC Equipment Division with a range of suggestions for improvement. In February 1932 Martin built for his own account, a new model of the 123 with two Wright R-1820 Cyclone engines. It had a speed of 317 km/h (197 mph), which was faster than competing aircraft. With the designation XB-907, the prototype was tested on Wright Field.

Several problems occurred, such as vibrations from the engines, instability during flight and furthermore the landing speed was too high; this turned out to be 146 km/hr (91 mph). So it was sent back to the Martin factory with a list of suggestions for improvement.

Partly due to the impact of the stock market crash of 1929 the design had now become vital for the survival of the Martin factory. Martin went to work on the results of the tests to improves the Martin 123.

The Martin 123 received extended wings, integrated with the hull and more powerful Cyclone engines mounted in new streamlined NACA caps.

The landing gear was changed and a new nose turret was developed.

 

In October 1932, the XB-907A was ready. The device was not only faster than the competing Boeing XB-9 and Douglas XB-7, but was also just as fast as the latest fighter aircraft of the USAAC from that time.

In January 1933 an order for 48 aircraft was scooped.

The XB-907A, was now referred to as XB-10 and 13 similar YB-10's had to be delivered plus one YB-10A for testing Wright engines with turbo compression had to be delivered.

Seven YB-12s were to be built for testing with Pratt & Whitney R-1690 Hornet engines, followed by 25 ordinary B-12A with the same engines, but equipped with extra fuel tanks and floating chambers and finally an experimental XB-14 with new Pratt & Whitney R-1830 Twin Wasps.

The YB-10 and YB-12 were delivered in early 1934 and were soon deployed for an unusual mission. All airmail contracts were cancelled due to corruption, and airmail now had to be taken care of by the USAAC.

The large, fast aircraft proved to be a godsend because of their reliability and security.

After these successes, Martin was actually expecting more large orders. Despite discussions Martin received contracts for 103 aircraft, in the final B-10B version with Wright R-1820/33 engines, spread over fiscal years 1934 and 1935.

The B-10's did service in every bombardment group of the Air Corps. In 1935 some were used for tests of Norden precision bomb sights.

The success stimulated the development of larger, long-range bombers which would replace the B-10, especially the Boeing B-17 Flying Fortress.

Already in 1936the USAAC lost interest in B-10 bomber. A few were tested as attack and observation plane, referred to as A-15 and D-45.

  Despite a number of disputes with Martin about the design and occurring construction defects in the B-10 series, in the spring of 1940, yet 119 of the 151 aircraft were still in service. Most were used as target tugs, and for training as a B-10M and B-12AM, though seventeen aircraft were still in operational service in the Philippines.

In 1936, the Martin 139 was released for export and 189 aircraft were eventually sold abroad.

The Soviets were in the summer of 1936, the first with the purchase of a single copy and blueprints, soon followed by the Netherlands East Indies, China, Siam, Argentina and Turkey with various orders.

The Dutch were the best customers with the purchase of a total of 120 aircraft in four different versions for the defence of the Dutch East Indies.

Foreign orders for Model 139 Martin kept the factory busy until 1939. One of the Argentine Martins is the only survivor of the type and was completely restored in the pre-war Air Corps colours and can be seen in the Air Force Museum at Wright-Patterson Air Force Base.

 

Technical information Glenn Martin WH-1
Dimensions:
Length: 13,6 m Wing span: 21,5 m
Height: 4,7 m Wing area: 63 m2
Weights:
Empty weight: 4391 kg Max. start weight: 6680 kg
Performance:
Cruising speed: 310 km/hr Max. speed: 343 km/hr
Climbing speed: 420 m/min    
Service Ceiling: 7380 m Range: 1996 km
Miscellaneous:
Engine type: Two Wright Cyclone R-1820-F53 rated 750 hp
Crew: Three men
Armament: Three 7.62 mm machine guns; 1000 kg bombs

 

Technical information Glenn Martin WH-2
Dimensions:
Length: 13,6 m Wing span: 51,5 m
Height: 4,7 m Wing area: 63 m2
Weights:
Empty weight: 4391 kg Max. start weight: 6680 kg
Performance:
Cruising speed: 310 km/hr Max. speed: 343 km/hr
Climbing speed: - m/min    
Service Ceiling: 7380 m Range: 1996 km
Miscellaneous:
Engine type: Two Wright Cyclone R-1820-G3 rated 840 hp
Crew: Three men
Armament: Three 7.62 mm machine gun; 1000 kg bombs

 

Technical information Glenn Martin WH-3 / WH-3A
Dimensions:
Length: 13,6 m Wing span: 51,5 m
Height: 4,7 m Wing area: 63 m2
Weights:
Weight (empty) - kg Weight (maximum) - kg
Performance:
Cruising speed: 310 km/hr Max. speed:  > 343 km/hr
Climbing speed: - m/min    
Service Ceiling: 7380 m Range: 1996 km
Miscellaneous:
Engine type: Two Wright Cyclone R-1820G-102 rated 900 hp each
Crew: Three men
Armament: Three 7.62 mm machine gun; 1000 kg bombs

 


In the mid thirties of the twentieth century several ideas were circulating about the defence and the rather young air force. One of these ideas was that an attack with bombers was the best way to defend.
The staff of the NEIAF supported this idea and asked several aircraft factories for an offer.
Fokker offered the Fokker T-V, which was still in development at that time. The American Martin company offered model 139, a version of the all metal Martin B-10. The B-10 was faster than the fighters in operational use at that time.
Finally the Martin 139 was selected and a series of 13 examples was ordered under the designation WH-1 as a replacement of the old Fokker C.V. [WH means Wright-Holland]

The planning foresaw the delivery of 39 aircraft, to be built under license in the Netherlands. Due to shortage of building capabilities it was decided to have the aircraft being built by the Martin aircraft factory. March 1937 a second series of 26 aircraft under the designation WH-2 was ordered.

The first WH-1, registered M-501, c/n 656, was handed over to the NEIAF on September 2, 1936. M-501 and M-502 arrived in December in the Dutch East Indies. M-502 made its first flight in January 1937 from air base Andir.

The second series was improved in several ways: more powerful Wright Cyclone G-3 engines rated 875 hp each., the Hamilton Standard–propeller with two positions was replaced with a Curtiss Electric ‘constant speed’ propeller. Furthermore the cowling was improved and more streamlined, a NSF VR-34B radio and also an auto-pilot was added.
The maximum speed was about 40 km/hr higher, the range was enlarged with about 10 % and the bomb load was about 20 % larger.
The first WH-2, serial M-514, construction nr. 717 was handed over in December 1937. All WH-2's were delivered in October 1938, so three divisions each with thirteen bombers (two spare, two in maintenance and nine operational) were operational.

The Martin 139 was developed to the Martin 166. This model had one single canopy, the cross section of the fuselage was enlarged, so more bombs could carried. The wings were slightly oblique backwards and the engines were replaced with the more powerful Wright Cyclone GR-1820-G5 rated 1000 hp each. For commercial reasons this model was called Glenn Martin 139 WH-3.

By the end of December 1937 a third contract for the delivery of 39 WH-3 was signed. The acceptance of the first WH-3, registered M-540, construction nr. 775, was may 1938.

November the same year a fourth contract was singed for the delivery of 40 Wh-3A’s. This type was identical to the WH-3, except that it was equipped with two Wright Cyclone R1820-G102 engines rated 1200 pk each.

The first WH-3A, serial M-579, construction nr. 837 was handed over in December 1938. April 1939 the third and last bomber division, VlG-III was operational at air base Tjililitan.

By the end of 1939 seven Martins were lost, 2 WH-1, 2 WH-2 and 3 WH-3’s.

When the Japanese attacked the Dutch East Indies the following units were operational:

Andir: 1-VlG-I and 2-VlG-I 9 Wh3/Wh-3A’s each plus 2 spare aircraft
Singorasi 1-VlG II with 3 Wh2’s; 9 Wh-3/Wh-3A’s plus two spare aircraft
Tjililitan 1-VlG II and 3-VlG III each 9 Wh3/Wh-3A’s plus 2 spare aircraft
Kalidjati 7e division with 1 HW-1, 2 Wh-3 and 6 Wh-3A
WH-1-patrouille with 3 WH-1 plus one spare aircraft

At the end of November 1941 so still operational:

  • three examples of the WH-1 plus one reserve;
  • Thirteen examples WH-2 plus 2 reserve;
  • Thirty-five examples of the WH-3 / WH-3A plus 5 reserve.
  • Not operationally deployable by maintenance or used for instruction, were 4 examples WH-1; six WH-2 and two WH-3 and three WH-3A.

DUTCH AIR FORCE IN BURMA - 1942; Kallang Airfield, Singapore 1941

So at the end of November 1941 operational were 3 WH-1's plus 1 spare; 13 WH-2's plus 2 spare; 35 WH-3/WH-3A plus 5 spare. Further, because of maintenance or training 4 WH-1s ; 6 WH-2s and 2 WH-3s and 3 WH-3As were not in operational use.

The first actions with the Martins were in the Borneo area. The Japanese were eager to conquer the oil fields. Soon the day light attacks were very hazardous. Alas the crews were hardly trained in night attacks.
During the three months of war many aircraft were lost in action.
(Via P. Guit) B.Guit flew with pilot officer Yland on Martin M-611. This aircraft was shot down on January 24, 1942 during the landing on Samarinda II together with two other aircraft. They came from Singosari (Singorasi as mentioned is not correct spelled). On January 25, 1942 they were evacuated in a Lodestar with a total of 30 men to Java , because not enough aircraft were available at Samarinda II.
By the end of February one succeeded to fly with the only Martin, M-585, left to Broome, Australia. The Martin was handed over to the USAF, which used it registered 42-68358.
The other aircraft probably eighteen examples were captured by the Japanese. Fifteen aircraft could be repaired to airworthy condition and several were handed over to Thailand. Thailand had bought six Martin 139’s in 1937. After the war about five Martins were left, which were in use until 1949.

Luitenant-vlieger P.G. Tideman (1933-1985) looking over his shoulder to the airgunner- co-pilot behind him in a Glenn Martin 139 WH-3 bomber.
[Enclosed photo from BeeldBank NIMH. Click on photo for ordering information]

 


The WH-3A’s were originally registered by the Martin factory M-579 till M-620. Because the serials in the M-600 range were not correct, these numbers were changed in August 1940 in M5100 till M5120.

An explanation of the registration system used: The NEIAF used a system in which the letter was a code for the aircraft factory and the first number referred to the purpose of the aircraft.
So M meant Martin and "5" meant bomber. The other numbers were in fact the aircraft number.

The serials were applied in white on the sides of the fuselage and the numbers were applied, in black on the front of the wing.

Glenn Martin 139 WH-1

Serial
Serial
Constr. nr.
Constr. nr.
Date in service
Date in service
Date out of service
Date out of service
Notes
notes
M-501 664 02-09-1936 09-03-1942 Captured by the Japanese at Andir.
M-502 665   09-03-1942 Captured by the Japanese at Andir.
M-503 666      
M-504 667   09-03-1942 Captured by the Japanese at Andir.
M-505 668      
M-506 669      
M-507 670   09-03-1942 Captured by the Japanese at Andir.
M-508 671   09-03-1942 Captured by the Japanese at Andir.
M-509 672   09-03-1942 Captured by the Japanese at Andir.
M-510 673   25-01-1942 Emergency landing in sea near Biliton
M-511 674   09-03-1942 Captured by the Japanese at Andir.
M-512 675      
M-513 676   09-03-1942 Captured by the Japanese at Andir.

 

Glenn Martin 139 WH-2

Serial
Serial
Constr. nr.
Constr. nr.
Date in service
Date in service
Date out of service
Date out of service
Notes
notes
M-514 717      
M-515 727      
M-516 728   21-01-1942 Destroyed during Japanese bombardment.
M-517 729      
M-518 730      
M-519 731      
M-520 732   05-03-1942 Damaged due to air attack Andir; used for spare parts.
M-521 733   05-03-1942 Damaged due to air attack Andir; used for spare parts.
M-522 734      
M-523 735   09-03-1942 Captured by the Japanese at Andir..
M-524 736   24-02-1942 Written off after emergency landing because of engine failure.
M-525 737      
M-526 738      
M-527 739      
M-528 740      
M-529 741      
M-530 742      
M-531 743   16-02-1942 Emergency landing (in swamps) after being shot at by FLAK. Located in 1985 and parts of wing and other parts were preserved and sent to Militaire Luchtvaart Museum Soesterberg.
M-532 744      
M-533 745      
M-534 746      
M-535 747      
M-536 748      
M-537 749   09-02-1942 Shot down near Tjililitan
M-538 750   09-02-1942 Shot down near Tjililitan
M-539 751      

 

Glenn Martin 166 WH-3 and Wh-3A

Serial
Serial
2nd Serial
2nd Serial
Constr. nr.
Constr. nr.
Date in service
Date in service
Date out of service
Date out of service
Notes
notes
Serial2nd SerialConstr. nr.Date in serviceDate out of serviceNotes
Glennn-Martin WH-3
M-540   775   20-02-1942 Destroyed due to Japanese attack of Kalidjati
M-541   776      
M-542   777   09-03-1942 Partly destroyed by ML-KNIL; captured by Japanese
M-543   778      
M-544   779   20-02-1942 Destroyed due to Japanese attack of Kalidjati
M-545   780   24-02-1942 Destroyed during Japanese bombardment of Andir
M-546   781   20-02-1942 Destroyed due to Japanese attack of Kalidjati
M-547   782   10-01-1942 Written of after emergency landing
M-548   783      
M-549   784   09-03-1942 Partly destroyed by ML-KNIL; captured by Japanese
M-550   785      
M-551   786   28-12-1941 Shot down near Miri
M-552   787   12-01-1942 Written off after nightly emergency landing
M-553   788      
M-554   789   05-02-1942 Crashing during take off from Pameumpeuk
M-555   790   23-12-1941 Crashed
M-556   791   15-02-1942 Captured by Japanese, after conquering of Singapore.
M-557   792      
M-558   793   27-01-1942 Destroyed during Japanese air attack of Oelin
M-559   794   24-12-1941 Burned during bombardment
M-560   796   20-02-1942 Destroyed due to Japanese attack of Kalidjati
M-561   797      
M-562   798      
M-563   799      
M-564   800   27-01-1942 Destroyed near Japanese air attack of Oelin
M-565   801      
M-566   802      
M-567   803      
M-568   804   03-03-1942 Shot to fire
M-569   805      
M-570   806      
M-571   807   18-12-1941 Shot down near Miri
M-572   808   19-01-1942 Emergency landing Zuid-Malakka after being attacked
M-573   809      
M-574   810      
M-575   811      
M-576   812   15-02-1942 Captured by Japanese, after conquering of Singapore.(was under repair)
M-577   813      
M-578   814   16-02-1942 Shot down near Palembang
Glenn-Martin WH-3A
M-579   837   25-01-1942 Destroyed during Japanese attack of Samarinda II
M-580   838   20-02-1942 Destroyed during Japanese attack of Kalidjati
M-581   839   13-01-1942 Shot down over Tarakan
M-582   840      
M-583   841      
M-584   842      
M-585   843   08-03-1942 Escaped to Australia; handed over to USAAF
M-586   844   01-01-1942 Shot down near Penang
M-587   845      
M-588   846   20-01-1942 Destroyed by own personnel at Manggar
M-589   847      
M-590   848      
M-591   849      
M-592   850   05-03-1942 Shot down near Kalidjati
M-593   851      
M-594   852      
M-595   853      
M-596   854      
M-597   855   01-01-1942 Shot down near Penang
M-598   856   09-03-1942 Partly destroyed at Tasikmajala by own personnel. Captured by the Japanese
M-599   857   26-02-1942 Shot down near Banka
M-5100 M-600 858      
M-5101 M-601 859      
M-5102 M-602 860   09-03-1942 Partly destroyed at Tasikmajala by own personnel. Captured by the Japanese
M-5103 M-603 861   13-01-1942 Shot down over Tarakan
M-5104   862      
M-5105   863   09-03-1942 Captured by the Japanese at Andir. Was under repair.
M-5106   864      
M-5107   865      
M-5108   866   03-03-1942 Shot down over Kalidjati
M-5109   867      
M-5110   868   24-01-1942 Shot to fire during landing at Samarinda II-West
M-5111 M-611 869   24-01-1942 Shot to fire during landing at Samarinda II-West
M-5112 M-612 870      
M-5113 M-613 871      
M-5114 M-614 872   01-03-1942 Captured by the Japanese at Kalidjati
M-5115 M-615 873   28-12-1941 Shot down near Miri
M-5116 M-616 874      
M-5117 M-617 875      
M-5118 M-618 878      
M-5119 M-619 1094      
M-5120 M-620 1095   12-01-1942 Emergency landing Barisan mountains

 


1/72nd Scale

Kits

  • William Brothers
    • Kit 72-210: a kit of a Martin B.10B

Modelling add-on

  • Falcon
    • VAX30: Canopies of US Aircraft in foreign Service (T6, Baltimore, Maryland, Hudson, Ventura, B10, Vengeance)
  • Aeroclub
    • Set E021: Wright Cyclone 1820 F Srs (Curtiss Condor etc)
    • Set E025: Wright Cyclone 1820 G Srs (Curtiss SC1, etc)
  • Aires
    • Set 7092: Wright R1820 cyclone engine
  • Red Roo
    • RRR72114: Lockheed Hudson Engines (Wright Cyclone)

Decals

  • Superscale
    • Set 72-127: A set decals for Martin B10 (7BG,Al.FLT,US Mail,9BG,Turkey,KNIL). Note that the paint scheme for the NEIAF is not correct.
  • Dutch Decal
    • Set 72020: decals for several aircraft such as Wh-1 M507 and M505 (yellow/blue paint scheme)
    • Set 72043: decals for several aircraft such as WH-1 M502 and Wh-2 M514
    • Set 72068: decals voor verschillende toestellen zoals Dornier Do-215B ML (LVA - what if); DeHavilland DH-85 LVA, 961; Martin WH-2 M515; Douglas DB-7B, Consolidated PBY-5/A Y38; Y-39 en Y-75;  Brewster B-340 (Ml-KNIL - what if), Ryan STM RO65; Fokker D.XXIII ( ter vervanging van de onjuiste driehoeken van de recent uitgegeven RS kit).
  • FlevoDecal
    • Set FD72-012 ML KNIL 1939-1942:A set decals containing decal for five different Brewster Buffaloes plus Curtiss Hawk 75, Curtis CW-22, Curtiss CW-22, Lockheed Lodestar, Ryan STM; Lockheed 12, Bücker Bu131 Messerschmitt Me-108 and Martin WH-1 and WH-2.

 

1/48th Scale

Kits

  • --
    • Kit --: --

Modellig add-on

  • --
    • Kit --: --

Decals

  • --
    • Kit --: --

 


First scheme:

At delivery the aircraft were in standard USAAC colour scheme of a blue fuselage, Light Blue Shade 23, and yellow wings and tail units, Yellow Shade 4. The rudder was in red, white and blue, but painted over in 1939. It is unlikely that this colour scheme had also the orange triangle applied, which were in use from the second half of 1939.

Second scheme:

During 1940 all remaining aircraft were sprayed in Olive Drab, Shade 41 (called "Old Blad" (old leave)); the under side was sprayed with aluminium dope. Also the Dutch roundels were replaced with the orange triangles in four positions, not on the undersides of the wings! Initially the rudder was also painted orange, but soon the rudder was painted in Olive Drab. Uncertain is whether the triangles were reduced in size like the RNlNAS did. I haven't seen any photo's of this.

During 1941 several Martins had a two tone camouflage pattern applied on the upper surfaces of the wings, colours used were "Oud Blad" and "Jong Blad" (Olive Drab, shade 41 and Medium Green, shade 42).

February 1942 the remaining aircraft had the triangles replaced with the Dutch flag.

SchemeColour nameFS numberANAHumbrolXtraColorVallejo Model ColorValejo Model Air
Standard #1: Delivery schemeFuselage Blue Shade 23 15109 501   X124    
Wings etc. Yellow Shade 48 13538 50 154 X213 70.953 71.078
From midst of 1940 all remaining aircraft. Some aircraft had a camouflage pattern applied with "Jong Blad" (= Med. Green 42)
 Standard #2Uppersides
Oud Blad & Jong Blad ( on some aricraft)
Olive drab shade 41 33070 613 66 X114 70.889 71.034
Medium Green shade 42 34092 612 149   70.885 71.014
Undersides Aluminium     191 / 56 X126 70.864 71.062

Check www.paint4models.com for an extensive conversion table with lots of colour and paint systems.

 

Martin 139 WH-1

GlennMartin WH1 1 SMALL
Delivery scheme Martin 139 WH-1.
GlennMartin WH1 1 SMALL
Second colour scheme of the Martin WH-1: 'Jong Blad' on upper surfaces and bare metal on lower surfaces.

 

Martin 139 WH-2

GlennMartin WH2 1 SMALL
Delivery scheme Martin 139 WH-2.
GlennMartin WH2 2 SMALL
Second colour scheme of the Martin WH-2: Jong Blad on upper surfaces and bare metal on lower surfaces.
GlennMartin WH2 3 SMALL
Third colour scheme Martin 139 WH-2: A pattern of 'Jong Blad' and 'Oud Blad' on upper surfacess and bare metal on lower surfaces.
As a source for this scheme I used the scheme published by Peter C. Boer on "Mars et historia" .

 

Martin 166 WH-3 and WH-3A

GlennMartin WH2 1 SMALL
Delivery scheme Martin 166 WH-3.
GlennMartin WH2 1 SMALL
Colour scheme Martin 166 WH-3: camouflaged ('jongblad') with oranje triangles as national markings.

 

GlennMartin WH2 1 SMALL
Delivery scheme Martin 166 WH-3A.
GlennMartin WH2 1 SMALL
Colour scheme Martin 166 WH-3a: camouflaged ('jongblad') with oranje triangles as national markings.
GlennMartin WH2 1 SMALL
Colour scheme Martin 166 WH-3A: camouflaged ('jongblad' with a pattern of "oud blad") with oranje triangles as national markings.

 


Literature.

Militaire Luchtvaart in Nederlandsch-Indië in beeld. Deel 1 Hugo Hooftman Pag. 108 - 114 1978 Uitgever: Europese Bibliotheek, Zaltbommel
Militaire Luchtvaart in Nederlandsch-Indië in beeld. Deel 1 Hugo Hooftman Pag. 115 - 132 1978 Uitgever: Europese Bibliotheek, Zaltbommel
Air Enthusiast 22: Batavia's big sticks, the story of the Martin 139 bombers Gerard Casius Pag. 1 - 20 1983 Uitgever: Pilot Press Ltd., Bromley, Kent
AVIA: 42e jaargang nummer 10: Luchtvloot van Plastic: De ML-KNIL Martin bombswerper Hans Loeber Pag. 345 - 347 1983 Uitgevers Wyt, Rotterdam
Air Enthusiast 22: Batavia's big sticks, the story of the Martin 139 bombers Gerard Casius Pag. 1 - 20 1983 Uitgever: Pilot Press Ltd., Bromley, Kent
40 Jaar luchtvaart in Indië Gerard Casius & Thijs Postma Pag. 4; 50; 52; 66 - 67 1986 Uitgeverij De Alk, Alkmaar
De Luchtstrijd rond Borneo P.C.Boer   1987 Uitg. Van Holkema & Warendorf
De Luchtstrijd om Indië P.C.Boer e.a.   1990 Uitg. Van Holkema & Warendorf
Squadrons van de Koninklijke Luchtmacht (derde herzien druk) Willem Helfferich Pag. 18 - 1994 Uitgevers Wyt, Rotterdam

 

Websites.

Special thanks to mr M.T.A. Schep en M. Schonfeld for their information regarding the differences of the various types.