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[Herra Tohtori]

B-25 destroying Japanese shipping on Pacific Islands. The 75mm cannon is quite effective but needs some sort of sound effect to indicate when it is loaded so pilot knows when it's available after firing it...

[S3231541]

You want it to appear as a HUD message or integrated in the cockpit?

[Herra Tohtori]

You want it to appear as a HUD message or integrated in the cockpit?

I was thinking of making a sound effect of the shell being removed from the breech, new shell being loaded and the breech being closed. I can't remember if these cannons had autoloaders though, or if they had to be manually loaded by crew after each shot (I think they were modified versions of the gun used in Sherman tanks). If they were loaded by crew, they would have used the intercom to call out when they were loading and when the gun was loaded, like they do in tanks. Problems I see with this is that it may be difficult to sync the audio with the time when the cannon loading is actually finished, and secondly if the sound effect included a crew member calling something like "Ready to fire" every time after loading, it could get old fairly soon.

A visual indicator is certainly another option. I expect a HUD message would be somewhat easier to make, perhaps just with a message like "Cannon: Loading" and "Cannon: Ready". It would definitely be functional, with no added cockpit indicators to complicate things.

From simulation perspective though, an indicator integrated to the cockpit would be absolutely brilliant. It could be as simple as an indicator light that shows when cannon is ready to fire. However I'm not sure how accurate such an indicator would be in the B-25 cockpit. I seem to also recall that the B-25 variants used against shipping had a radar ranging gunsight to make the cannon effective beyond AAA range of the Japanese ships, and I'm sure this instrumentation also included a way for pilot/gunner to know when the cannon could be fired.

[S3231541]

I won't do it, to be honest but if you or anyone want to try edit java to enable this, just contact me, I have a few idea that could enable all the above that you want.

[Herra Tohtori]

I won't do it, to be honest but if you or anyone want to try edit java to enable this, just contact me, I have a few idea that could enable all the above that you want.

Well the simplest way I was thinking of doing it was to lengthen the weapon's internal firing sound (heard in cockpit) to include the necessary information for the gun operator/pilot. If it's an autoloader, I would include some mechanical clinking and whirring with some sort of clank at the end, if it's crew-loaded, include some bangs and clanks and possibly a crew member saying "gun ready" or whatever seems suitable. All I'd need is a few sound effects and I'd need to know the weapon's loading cycle time (it seems to be 12 seconds between shots).

I have no required skills to add this kind of thing through java coding and precious little time to dedicate to learning new things. So other things sort of take priority from my time. I could make a new request thread about this, in case someone interested in B-25's would like to add the rangefinder gunsight or the visual loading indicators.

[S3231541]

I don't have much time myself too since I'm doing a lot of projects right now. I can split this thread to make it a new topic in the request section.

[Herra Tohtori]

Thanks for transferring the posts into a new thread, I was sort of contemplating on making a request post to get the discussion out of the screenshot thread but you did the job for me :3

~S~

[Herra Tohtori]

Here's some information I found out:

-the 75mm cannon was hand-loaded by navigator
-the B-25H variants used a lighter version of the gun but it used same ammunition, same muzzle velocity and presumably same loading speed
-the loading cycle for the weapon seems to be approximately 12 seconds in IL-2 (not sure how that reflects hand-loading speed of the actual gun).


Source: http://home.mchsi.com/~anderson.kevin/b25h_pictures.html

The site is scheduled for removal, so I'll quote the relevant bits here:

A Photo Tribute to the B-25H Series

By Kevin Anderson, Dubuque, Iowa

The H series of the B-25 (and its Navy PBJ-1H equivalent) was an awesome airplane.

Built by North American Aviation (NAA) and used primarily during World War II from mid-1944 and into 1945, this series of the B-25 contained a 75-mm cannon in the nose, hand-loaded by the navigator-cannoneer, that was fired by the pilot simultaneously along with four .50-cal. machine guns also mounted in the nose (each with 400 rounds per gun), plus either two or four more machine guns mounted in blister packages on the sides of the cockpit (also with 400 rounds per gun). Designed primarily to be used for interdiction work against shipping and other fortified targets where a cannon could be deadly, the H series was the final development of testing begun by "Pappy" Gunn in the Pacific and first implemented in the B-25C1 "Commerce Strafers." The production B-25G that followed first employed the 75-mm cannon (the M-4) and was initially known as a fighter-bomber, before the AAF adopted that term for bombing fighters. The later B-25H retained the cannon, albeit a lighter version (the T13E1), which allowed for more forward-firing machine guns, plus additional armor plating to protect the crew.

The B-25H ended up not being used as much as planned. This was in principle due to its configuration as an attack bomber and changes in AAF tactics, its lack of factory dual controls, higher maintenance due to the wear and tear caused by the cannon, and a widespread lack of targets of the type needing the cannon (such as low altitude bombing missons common in mid- and late-1944 in the Pacific). Although tested by a variety of combat groups in mid-1944, those B-25H models that remained in combat were used by a few squadrons who specialized in this type of use, particularly in the South and Southwest Pacific and in Southeast Asia. The units that made more extensive use of the B-25H include: the 100th BS of 42nd BG (13th Air Force); the 498th BS of the 345th BG, squadrons of the 38th BG, plus the 418th Night Fighter Squadron, all of the 5th Air Force; squadrons of the 341st BG of the 10th and 14th Air Forces in Southeast Asia, plus the 1st Air Commando Group of the 10th Air Force; and by the Marine Corps in the Central Pacific.

Only 1,000 B-25H planes were manufactured (including the Navy variant, the PBJ-1H), all built at the Inglewood factory of North American Aviation and assigned sequential tail numbers from 43-4105 through 43-5104. When there was a shortage of the newer light-weight cannon, Republic Aviation (of Evansville) finished several H-1 planes with the original heavier cannon as used in the G series; for these planes, the extra weight also meant a reduction of the nose guns by half. [See this webpage, http://home.att.net/~jbaugher2/b25_15.html, for details about the H series. Or for a summary on all the B-25 versions, try this webpage, http://www.vectorsite.net/avb25.html.]

Besides personally believing this series to be the best looking of all the B-25 production types, the H series also holds a particular interest for me due to two personal connections:

    First, the B-25H was the type of plane my uncle, 2LT Roy L. Anderson, AC, trained to fly for combat and was the type in service with the 100th Bombardment Squadron, 42nd Bombardment Group (Medium), 13th Air Force, when Roy first started combat flying with the squadron in June 1944. The 100th BS flew the H series briefly, from June through mid-September 1944, after which they were replaced with the newer J-1's finding their way to the Pacific. [At the time, in later 1944, most of the activity of the 13th AF was shifting away from interdiction against shipping toward that of medium-altitude bombing, which was totally inappropriate for a cannon-firing strafer such as the H. It wasn't until 1945 in the Philippine campaigns that strafing again took on widespread importance with the 13th AF, which by then could be handled quite nicely by the newer and more flexible solid-nose 8-gun strafing and rocket-firing versions of the B-25J that were then available.]

    And second, it was while flying as a flight engineer/crew chief on a TB-25H, tail number 43-4241, that another uncle of mine, CPL Chester S. Anderson, AC (an older brother of Roy's), lost his life in a stateside airplane crash on November 10, 1945, in marginal weather amongst hills along the Kentucky-Tennessee border.

Below is a series of photographs that I've collected from various places on the web to both illustrate and pay tribute to this lesser known series of the B-25, followed by further data on wartime allocation of the H series. I will continue to add information and pictures as they become available. Enjoy!

Photo Sources:

    [1] Donald Robertson, Jr., son of 1LT Donald C. Robertson, pilot with the 100th BS(M)
    [2] National Museum of the USAF, Factsheet and photos on the B-25H [http://www.nationalmuseum.af.mil/]
    [3] B-25H/PBJ-1H Pilot's Manual (the photos from which were provided in a forum discussion on this website: http://www.netwings.org/dcforum/DCForumID43/1300.html
    [4] Pictures of a modern-day "Barbie III," the only known flyable B-25H, including this site, http://www.midwaysailor.com/photos/mitchell-barbie3.html, and this site, http://www.webshots.com/search?query=B-25-H+'Barbie+III'. And here is a link to photos on the website of the owners of the modern-day Barbie III, the Warbirds Unlimited Foundation: http://www.warbirdsunlimited.org/aircraft_gallery.htm
    [5] A History of the 42nd Bombardment Group, Authors: Cohn, Maj R. H. and Wachs, Capt Marvin C. and Strong, Cpl. Charles W. Copyright 1946 by the Crusader, 42nd Bomb Group, Typography, engravings and printing by Army and Navy Pictoral Publishers, Army and Navy Publishing Company Building, 234 Main St., Baton Rouge, LA, 205 pages.
    [6] http://www.vectorsite.net/avb25.html
    [7] http://www.chindits.info/Thursday/AirCommando.htm
    [8] http://uboat.net/allies/aircraft/b25.htm
    [9] http://www.ferreamole.it/images/m24/b25.htm
    [10] http://www.acepilots.com/planes/b25.html
    [11] http://www.bamfbamrs.be/B25/B25-en.htm
    [12] A forum discussion about the 75mm cannon of the G and H models on the resource site, armyairforces.com.
    [13] http://www.aerofiles.com/b25-cannon.jpg
    [14] Pictures I personally received in 1975 from the Public Relations office of Rockwell International, successor company to North America Aviation.
    [15] Pictures originally from North American Aviation, which I received from Tony Strotman, who similarly earlier had a photo tribute to the B-25H/PBJ-1H.
    [16] Widipedia (http://en.wikipedia.org/wiki/File:PBJ-1H_VMB-613_open_bomb_bay.JPG)
    [17] Diagrams scanned from B25 manuals by Yves Marino.

I must give due credit to Phil Marchese for his important contributions to the above description of the H series, which also includes information from Joe Baugher's webpage, plus from other sources here and there on the B-25H and PBJ-1H.

A picture from the pilot's manual, showing the instrument panel and cockpit of the B-25H/PBJ-1H. What distinguished the H series from all other B-25s was the lack of factory installed dual controls for a co-pilot. This was a very controversial design desision made by the higher brass in the War Department, right up to General "Hap" Arnold himself, chief of the Army Air Force, which was another reason why the combat folks didn't particularly like the H model. In place of the co-pilot was a jump seat intended to be used by the navigator, but in reality often used by a second pilot, as the 100th BS and other groups in the Pacific still flew with a co-pilot who traded places with the pilot on long flights. Dual controls were added back to the production J and later types, but apparently many H's were also field and depot modified to include dual controls. [3]


The gun sight used by the pilot to target the machine guns and cannon, as well as for skip bombing. This particular sight, the N-3B, had to be manually adjusted by the pilot as the plane approached the target to account for the decreasing range and effects of gravity. The War Department also experimented with a forward-looking radar gun sight, the AN/APG-13 "Falcon," that could remotely adjust the sight based on adjustments made by the radar operator sitting to the pilot's right. Used by the Navy/Marine Corps, and also by the 14th Air Force, the radar gun sight worked best against shipping targets without a "cluttered" background to confuse the operator. To the best of my knowledge, none of the 13th and 5th Air Force units in the South Pacific used the radar sight, whereas it was used by both the 341st BG of the Army Air Force and VMB-613 Squadron of the Marine Corps. (If you are curious about the radar gun sight, see this webpage: http://www.riemarfamily.com/falcon%20in%20action.html.) [3]

The link to the Falcon radar can be accessed via the Wayback Machine:

http://web.archive.org/web/20110516142042/http://www.riemarfamily.com/falcon%20in%20action.html

I'm not really seeing any visual indicators dedicated to gun status, but then again I wouldn't know what to look for.

Most likely crews communicated the gun status from navigator/loader to pilot via intercom.

The biggest problem with my idea of adding the gun status announcement as a spoken message as a lengthened firing sound is that the "gun ready" message would then also play when the gun is out of ammunition. However, it would be better than nothing for sure.

[Fly!]

try: https://www.mediafire.com/?bqub0iul27khpgu
If interval is not right, let me know what u need in seconds.

[RooMan296]

Which B25 has the 75mm?? I'm still trying to locate it!

[wb21]

B-25G-1NA and B-25H-1NA, if I'm correct.

[RooMan296]

Thanks, I'll check em out! BTW, the new K109 has a load/reload sfx for it's killer cannon.