Mitsubishi C5M2 BABS

[Fatboy Coxy]

Hi all, I'm looking for information on the Mitsubishi C5M2 BABS, the last operational IJN version, which had a 950 hp Nakajima Sakae 12 engine fitted. Despite the increase in power, this model was, I read, a bit slower that the Mk I, due to extra equipment added.

 

[Wurger]

To begin with .. The C5M1 and C5M2 were the IJN designations for the Ki-15-I (Army Type 97 Command Reconnaissance Aircraft Model 1) and Ki-15-II (Army Type 97 Command Reconnaissance Model 2). The data below denies the C5M2 was slightly slower than the C5M1.

C5M1
Engine: Mitsubishi Zuisei 12 fourteen-cylinder air-cooled radial
Power: 780hp at take-off, 875hp at 11,810ft
Crew: 2 (pilot and radio-operator/ observer/ gunner)
Wing span: 39ft 4 7/16 in
Length: 28ft 6 17/32 in
Height: 11ft 4 13/32 in
Empty Weight: 3,538lb
Loaded Weight: 4,844lb
Max Speed: 291 mph at 14,040ft
Climb to 9,845ft in 4 min 51 sec
Service Ceiling: 27,000ft
Range: 725 miles
Armament: One flexibly mounted rear-firing 7.7mm Type 92 machine-gun

C5M2
Engine: Nakajima Sakae 12 fourteen-cylinder air-cooled radial
Power: 940hp at take-off, 950hp at 13,780ft
Crew: 2 (pilot and radio-operator/ observer/ gunner)
Wing span: 39ft 4 7/16 in
Length: 28ft 6 17/32 in
Height: 11ft 4 13/32 in
Empty Weight: 3,781lb
Loaded Weight: 5,170lb
Max Speed: 303mph at 14,930ft
Climb to 9,845ft in 3 min 58 sec
Service Ceiling: 31,430ft
Range: 691 miles
Armament: One flexibly mounted rear-firing 7.7mm Type 92 machine-gun

the info source: Mitsubishi C5M

 

[Fatboy Coxy]

Hi Wurger, thank you for this.

I also understand the C5M2 has the same engine as the A6M2 model 21, which must have helped with their logistics and maintenance.

I'm always confused by what the range of an aircraft is, my understanding is how far can it fly, but operationally you obviously want to return (hopefully), and so we would discuss its radius of operations. This then becomes quite fuzzy with whether we have maximum fuel, or maximum payload, and also how fuel efficient an aircraft can fly to and from target area. Oh and we haven't discussed loiter time over target.

The History of War web site Wurger has linked shows a range of 691 miles for the C5M2, but I know that flying out of Soc Trang, south French Indo-China (Vietnam) they were doing recon missions over Singapore, a distance of 580 odd miles. Does anyone know if the C5M2 operate with drop tanks or extra fitted tanks, or is 691 miles an operational radius.

 

[Wurger]

The Wikipedia site suggests the range: 2400 km what is about 1500 miles or 1300 NM. Judging by the info , the 691 miles is the operational range.

 

[Fatboy Coxy]

Aah, that makes a lot more sense.

 

[Shinpachi]

The C5M2 or its equivalent Ki-15-II could narrowly fly between Saigon and Singapore without the drop tank but it would be safer with it.

Ki-15-II_spec(fuel tank)

Source: Ki-15-II manual

 

[Wurger]

 

[Fatboy Coxy]

Hi Shinpachi, thank you for this, but as you mention the drop tanks, I have a question. The C5M1/2 originated from the Army Ki-15, did the Naval version use the same drop tank as the Army version, and were they the same tanks as those used by the Ki-27 Fighter. The reason why I ask is I am working through the Japanese Monograph 55, South East Area Air Operations Phase I, Nov-1941 - Feb-1942. The 3rd Air Brigade was tasked with attacking the airfields in Kelantan, Malaya, including Kota Bharu. The 59th Sentai equipped with Ki-27 fighters, was operating out of Konpong Trach, a distance of about 340 miles. I think they may have been using drop tanks, but there were concerns among the 3rd Air Division, as the numbers of drop tanks were low.

 

[Shinpachi]

Hi Shinpachi, thank you for this, but as you mention the drop tanks, I have a question. The C5M1/2 originated from the Army Ki-15, did the Naval version use the same drop tank as the Army version, and were they the same tanks as those used by the Ki-27 Fighter. The reason why I ask is I am working through the Japanese Monograph 55, South East Area Air Operations Phase I, Nov-1941 - Feb-1942. The 3rd Air Brigade was tasked with attacking the airfields in Kelantan, Malaya, including Kota Bharu. The 59th Sentai equipped with Ki-27 fighters, was operating out of Konpong Trach, a distance of about 340 miles. I think they may have been using drop tanks, but there were concerns among the 3rd Air Division, as the numbers of drop tanks were low.

Capacity of the drop tank for IJN aircraft like A6Ms was 330L (later 320L for wooden tank)
200L wooden wing drop tank was common between IJN and IJA.
They did not drop tanks if not necessary to do so.

 

[Shinpachi]

The first step of Malaya Campaign for IJA ground forces was to occupy the airfield in Singora, Thai.
Ki-27's flight range was 627 km (392 miles) with a drop tank or 350 km(219 miles) without it.
Distance between Kampong Trach FIC and Singora is about 573 km(358 miles).
They would not fly without drop tanks.

 

[Fatboy Coxy]

Hi Shinpachi, working from JM 55

page 20 of the PDF

I'm guessing they were flown in by transport plane

 

[Shinpachi]

I have not heard that they flew in by transport plane.
They only had to fly to Singora to gather for the next step in Malaya.

One way flight to Singora

Source: Aviation Fortress (航空要塞 1945)

 

[Fatboy Coxy]

Hi Shinpachi, thank you for this, but as you mention the drop tanks, I have a question. The C5M1/2 originated from the Army Ki-15, did the Naval version use the same drop tank as the Army version, and were they the same tanks as those used by the Ki-27 Fighter. The reason why I ask is I am working through the Japanese Monograph 55, South East Area Air Operations Phase I, Nov-1941 - Feb-1942. The 3rd Air Brigade was tasked with attacking the airfields in Kelantan, Malaya, including Kota Bharu. The 59th Sentai equipped with Ki-27 fighters, was operating out of Konpong Trach, a distance of about 340 miles. I think they may have been using drop tanks, but there were concerns among the 3rd Air Division, as the numbers of drop tanks were low.

Hi Shinpachi, I think I have misled us all, what I posted in bold is incorrect, I think the 59th Sentai was equipped with Ki-43 Hayabusa, and flying from Phu Quoc Island, and had to provide fighter cover over Kota Bharu. I also think the 64th Sentai, also out of Phu Quoc, but a different airfield, provided cover over Singora. The 1st and 11th Sentai, equipped with Ki-27, were either also at Phu Quoc, or staged out of there to land at Singora as soon as it was captured. I'm not sure about where the 77th Sentai operated, I need to research more on that.

 

[Shinpachi]

The 77th Sentai did not appear in Siemrea(JP pronunciation) of FIC until December 15, 1941

 

[JoeP]

Fatboy Coxy,
Hi, a friend highlighted your post for me this week and I thought I would post a response.
Data for the C5M2 is very convoluted and miss-understood.
The furthest documented "straight line" flight of a C5M2 is in excess of 2,606km (1,620miles) and this does not take into consideration typical operation parameters such as detours for weather, danger zones, loiter time over the target or possible alternate landing options, etc. The actual range of the C5M2 was far in excess of of this document figure, with a maximum range most likely greater than 3,250km with a drop tank.
Also, the statement that the C5M1 was a version of the Army Ki-15-I, and C5M2 was a version of the Ki-15-II is wholly inaccurate. While the C5M1 was a navailised version of the Ki-15-II airframe, the C5M2 was a wholly new variant of the airframe, far beyond that of the Ki-15-II.
In fact while the Army officially sanctioned Mitsubishi's development of the Ki-15-I into the Ki-15-II in December 1937, but the Army showed little interest in moving forward with the project as the performance of the Ki-15-I was so far ahead of all of its opponents at that time. This was a shortsighted decision and the Navy would in fact be the first service to adopt the improved aircraft into service as the C5M1 in April 1939, some 5 months before the Army accepted the Ki-15-II in to service.
I cover the whole development of the Babs family of aircraft in my 2 books ("Mitsubishi Babs Vol.I - the worlds first high-speed strategic reconnaissance aircraft" and "Mitsubishi Babs Vol.2 - the worlds first high-speed strategic reconnaissance aircraft", published in 2023 and 2024 respectively. These two volumes (over 438 pages) include 80 pages on the operational history and technical development of the C5M1 and C5M2 airframes, including details of the range and performance and a list of 19 units and higher organisations that operated the C5M.
Reviews of the books can be found at:

Mitsubishi Babs: The World's First High-Speed Strategic Reconnaissance Aircraft, Volume 1

Stratus and MMP Books are two closely cooperating publishing houses offering history and modeling books. In their range you will find publications in English (some of them with a Polish insert) and in Polish.

reviews.ipmsusa.org

Mitsubishi Babs: The World’s First High Speed Strategic Reconnaissance Aircraft, Volume 2

IntroductionThis book is the second volume on the history and development of the Mitsubishi Ki-15/C5M high speed reconnaissance aircraft, which was used by the Japanese Army and Navy in numerous roles before and during the course of World War II.Volume 1, which has already appeared in review on...

reviews.ipmsusa.org

Aviation of Japan æ¥æ¬ã®èªç©ºå²

A site dedicated to information and discussion about the history of aviation and aeroplanes in Japan and the Far East. æ¥æ¬ã¨æ±æ´ã®èªç©ºå²ã¨èªç©ºæ©ã«é¢ããå°éãµã¤ããçæ§ããã®æå ±ãã³ã¡ã³ãããå¾ã¡ãã¦ã¾ããï¼æ¥æ¬èªã§ãå¯ï¼

www.aviationofjapan.com

Regards,
Joe

 

[Fatboy Coxy]

Fatboy Coxy,
Hi, a friend highlighted your post for me this week and I thought I would post a response.
Data for the C5M2 is very convoluted and miss-understood.
The furthest documented "straight line" flight of a C5M2 is in excess of 2,606km (1,620miles) and this does not take into consideration typical operation parameters such as detours for weather, danger zones, loiter time over the target or possible alternate landing options, etc. The actual range of the C5M2 was far in excess of of this document figure, with a maximum range most likely greater than 3,250km with a drop tank.
Also, the statement that the C5M1 was a version of the Army Ki-15-I, and C5M2 was a version of the Ki-15-II is wholly inaccurate. While the C5M1 was a navailised version of the Ki-15-II airframe, the C5M2 was a wholly new variant of the airframe, far beyond that of the Ki-15-II.
In fact while the Army officially sanctioned Mitsubishi's development of the Ki-15-I into the Ki-15-II in December 1937, but the Army showed little interest in moving forward with the project as the performance of the Ki-15-I was so far ahead of all of its opponents at that time. This was a shortsighted decision and the Navy would in fact be the first service to adopt the improved aircraft into service as the C5M1 in April 1939, some 5 months before the Army accepted the Ki-15-II in to service.
I cover the whole development of the Babs family of aircraft in my 2 books ("Mitsubishi Babs Vol.I - the worlds first high-speed strategic reconnaissance aircraft" and "Mitsubishi Babs Vol.2 - the worlds first high-speed strategic reconnaissance aircraft", published in 2023 and 2024 respectively. These two volumes (over 438 pages) include 80 pages on the operational history and technical development of the C5M1 and C5M2 airframes, including details of the range and performance and a list of 19 units and higher organisations that operated the C5M.
Reviews of the books can be found at:

Mitsubishi Babs: The World's First High-Speed Strategic Reconnaissance Aircraft, Volume 1

Stratus and MMP Books are two closely cooperating publishing houses offering history and modeling books. In their range you will find publications in English (some of them with a Polish insert) and in Polish.

reviews.ipmsusa.org

Mitsubishi Babs: The World’s First High Speed Strategic Reconnaissance Aircraft, Volume 2

IntroductionThis book is the second volume on the history and development of the Mitsubishi Ki-15/C5M high speed reconnaissance aircraft, which was used by the Japanese Army and Navy in numerous roles before and during the course of World War II.Volume 1, which has already appeared in review on...

reviews.ipmsusa.org

Aviation of Japan æ¥æ¬ã®èªç©ºå²

A site dedicated to information and discussion about the history of aviation and aeroplanes in Japan and the Far East. æ¥æ¬ã¨æ±æ´ã®èªç©ºå²ã¨èªç©ºæ©ã«é¢ããå°éãµã¤ããçæ§ããã®æå ±ãã³ã¡ã³ãããå¾ã¡ãã¦ã¾ããï¼æ¥æ¬èªã§ãå¯ï¼

www.aviationofjapan.com

Regards,
Joe

Hi JoeP, thank you for your reply. Articles on the web covering the Bab's variants don't do enough justice to the naval versions, especially the C5M2. I also think the arrival of the superb Mitsubishi Ki-46 then overshadowed it as a reconnaissance aircraft. I've read through your reviews and in all honestly, the depth of information you have provided on this aircraft looks like a work of love, and I wish you well with the books success.

 

[JoeP]

Hi JoeP, thank you for your reply. Articles on the web covering the Bab's variants don't do enough justice to the naval versions, especially the C5M2. I also think the arrival of the superb Mitsubishi Ki-46 then overshadowed it as a reconnaissance aircraft. I've read through your reviews and in all honestly, the depth of information you have provided on this aircraft looks like a work of love, and I wish you well with the books success.

Thanks for the kind words and I will be producing 2 volumes on the Dinah at some point, as I was the advisor to the RAF Museum Ki-46-III restoration many moons ago.
In the meantime, I am working on the Ohka book.
All the best.
Joe

 

[Musec04]

I really loved the two Ki-15 volumes Joe and something along the same lines for the Dinah already has me salivating.

Regards,

Clint